International Journal of Bio-Inorganic Hybrid Nanomaterials

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 5-13

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Review on Graphene FET and its Application in Biosensing Mohammad Bashirpour Ph.D., Department of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran

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ABSTRACT *UDSKHQH DIWHU LWV ÂżUVW SURGXFWLRQ LQ KDYH UHFHLYHG ORWV RI DWWHQWLRQV IURP UHVHDUFKHUV EHFDXVH RI LWV XQLTXH SURSHUWLHV +LJK PRELOLW\ KLJK VHQVLWLYLW\ KLJK VHOHFWLYLW\ DQG KLJK VXUIDFH DUHD PDNH JUDSKHQH H[FHOOHQW FKRLFH IRU ELR DSSOLFDWLRQ 2QH RI SURPLVLQJ JUDSKHQH EDVH GHYLFH WKDW KDV DPD]LQJO\ KLJK VHQVLWLYLW\ LV JUDSKHQH ÂżHOG HIIHFW WUDQVLVWRU *)(7 7KLV UHYLHZ VHOHFWLYHO\ VXPPDUL]HV WKH UHFHQW SURJUHVV LQ IDEULFDWLRQ DQG DSSOLFDWLRQ RI *)(7 IRU YDULRXV ELRVHQVRUV 7KLV DUWLFOH EHJLQV ZLWK VKRUW GHVFULSWLRQ DQG KLVWRU\ RI LRQ VHQVLWLYH ÂżHOG HIIHFW WUDQVLVWRU ,6)(7 $IWHU WKDW DGYDQWDJHV RI JUDSKHQH ,6)(7 ZLOO EH VXPPDUL]HG 7KHQ *)(7 IDEULFDWLRQ SURFHVV LQFOXGLQJ JUDSKHQH VKHHW JURZWK GLIIHUHQW PHWKRGV GUDLQ VRXUFH HOHFWURGH GHSRVLWLRQ DQG OLWKRJUDSK\ DQG SDVVLYDWLRQ ZLOO EH GLVFXVVHG )LQDOO\ GLIIHUHQW DSSOLFDWLRQ RI *)(7 LQ GHWHFWLRQ RI 'HR[\ULERQXFOHLF DFLG '1$ S+ DQG SURWHLQ ZLOO EH SUHVHQW DQG TXDOLW\ RI *)(7 ELRVHQVRU ZLOO EH H[DPLQHG Keyword: *UDSKHQH ,6)(7 *)(7 '1$ 3URWHLQ %LRDSSOLFDWLRQ

1. INTRODUCTION Nowadays, the technologies that are applicable to detect protein, DNA (Deoxyribonucleic acid), antigenantibody and etc are time consuming, complex and expensive. For example, detecting DNA sequence with modern techniques needs several processing step. BioPROHFXOH FRQFHQWUDWLRQ DPSOLÂżFDWLRQ E\ 3&5 3RO\PHUDVH &KDLQ 5HDFWLRQ DQG ODEHOLQJ DUH ÂżUVW VWHS Microarrays of different cells utilize to detect different type of solute biomolecule. After that, expensive microarray laser beams are used to read cells [1]. In the past few years, researchers have introduces new electrical signal to eliminate these complex procedures. (*) Corresponding Author - e-mail: m.bashirpour@ut.ac.ir

Electrical detection methods exhibit highly sensitive detection of chemical and biological species because the surface analyte or analyte-analyte bindings occur very close to the channel. ISFET (Ion-Sensitive Field Effect Transistor) has received lots of attention due to their cheap price, small size, fast answer and the possibilities for mass production [2, 3]. ISFET needs no optical reading and abeles to sense biomolecules withRXW WKH QHHG RI 3&5 7KHUHIRUH ,6)(7 PLFURDUUD\V FDQ be used outdoors to control the spread of diseases and environmental pollution. Compatibility of ISFET with Modern microelectronics makes it possible to use am-

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 5-13

plifying and analyzing circuits with ISFET die on the VDPH FKLS ZLWKRXW H[WUD HIIRUW > @ 7KH SULQFLSOH RI DQ LRQ VHQVLWLYH ÂżHOG HIIHFW WUDQVLVWRU ,6)(7 ZDV ÂżUVW LQWURGXFHG E\ %HUJYHOG > @ LQ 7KH 6WUXFWXUH RI ,6)(7 ZDV EDVHG RQ LRQ VHQVLWLYH JDWH PHWDO R[LGH VHPLFRQGXFWRU ÂżHOG HIIHFW WUDQVLVWRU 026)(7 +RZHYHU WKH JDWH PHWDO FRQQHFWLRQ was intentionally removed exposing gate oxide. Different experiments by Bergveld illustrated that concentration of sodium chloride (NaCl) in solution results in variation of current between drain and source. ,Q QH[W ZRUNV 0DWXVR HW DO IRXQG WKH 026)(7 QDWLYH VLOLFRQ GLR[LGH 6L22) used as the ion-sensing membrane to be sensitive to concentration of sodium (Na+) as well as hydrogen (H+) ions in the analyte solution [6].

Silicon transistor, because of their simplicity and well known fabrication process primarily used as ISFET until recently that new low-dimensional structures such as graphene nanoribbon, Si nanowires [7] and carbon nanotubes [8], have been applied. This is because of their size, large surface to volume ratio, DQG SRWHQWLDOO\ KLJKHU VHQVLWLYLW\ 2QH RI SURPLVLQJ alternative for silicone ISFET is graphene based ISFET that has really unique characteristics [9]. Since, graphene sheet electrical characteristics are sensitive WR VXUIDFH FRQGLWLRQV JUDSKHQH ÂżHOG HIIHFW WUDQVLVtors (GFETs) have been reported in many research as biosensor for different analyte such as H+ ions, small molecules, proteins, DNA, viruses and cells [9].

Detection process takes place in ambient conditions where the analyte is in its reference condition. The analyte changes some properties in recognition layer

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that is detectable with transducer. Graphene ISFET ÂżUVW LQWURGXFHG E\ 'DV HW DO > @ LQ /DWHU WKH performance of such a device was studied by Ang et DO > @ DQG 2KQR HW DO > @ Graphene is a single layer of carbon atoms with hexagonal lattice. Electrons in graphene act like relativistic particles without mass, which contribute to very unique thermal and electrical properties. Its properties like high mobility, high saturation velocity for electrons and holes, good mechanical strength, high thermal conductance and ballistic transport made graphene attractive research area since its discovery in > @ 5HFHQWO\ EHFDXVH RI LWV JRRG ELRFRPSDWibility, graphene based biosensors received lots of attentions from researchers hoping to create devices that are smaller in size, cheaper in price and more reliable than other systems using current technology. Mechanism of this kind of sensors is that graphene channel conductance changes with different biological or chemical species adsorption on surface of channel.

Change in conductance results change in I-V characteristics. Biomolecules on the surface of the graphene act as electron donors or acceptors. The long HOHFWURQLF PHDQ IUHH SDWK LQ JUDSKHQH > @ RUGHU RI micrometers) implies that electrons can travel large distances through a device without being restricted.

These properties can be very useful in biosensors to make very sensitive devices. Although graphene ISFET possess high performances, there is lots of work needs to be done to conquest practical issues such as nanostructures uniformity and stability in fabrication SURFHVV > @ ,Q WKLV SDSHU ÂżUVW EDVLF SULQFLSOHV RI JUDSKHQH ,6)(7

Figure 1: Schematic diagram of a graphene based ISFET. Positive (or negative depending on the applied liquid-gate voltage) ions near the surface of the graphene make up the Debye layer [13].

6

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performance and fabrication process has been explained. After that, interface between electrolyte/graphene is investigated in detail. At the end, graphene ISFET application in wide range of biosensors like DNA, cell and protein sensors has been reviewed.

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 5-13

higher charge carrier mobility (material parameter) and the higher interfacial capacitance (depend on the device design).

3. GRAPHENE FET FABRICATION 2. GRAPHENE FET PERFORMANCE AND CHARACTRIZATION Graphene ISFET is like silicon ones with little difference that has huge effect on characteristics of transistor. The difference is graphene channel that makes device faster and more sensitive than typical silicon ,6)(7 ,Q WKH JUDSKHQH ,6)(7 FRQÂżJXUDWLRQ UHJXODtion of the channel conductance is controlled by gate voltage from a reference electrode placed on top of the channel, across an electrolyte and electrolyte acts as the dielectric [16]. The gate voltage compels ions at the graphene/electrolyte interface, which in turn derive charge carriers by capacitive charging of the ideally polarizable interface. In particular, it has been shown that, because of the ambipolar nature of graphene, adVRUEHG K\GUR[LGH 2+-) and hydronium (H32+) ions are able to regulate the channel conductance by inducing holes and electrons, respectively. Figure 2 shows a typical conductivity vs. electrochemical gate potential plot obtained in an ionic liquid. The reaction between solution with different pH values and the surface of JUDSKHQH KDV D VLJQLÂżFDQW HIIHFW RQ WKH FRQGXFWLYLW\ It is obvious that device conductivity reaches a minimum value at charge neutral point [16].

Higher conductance graphene FET is because of

Figure 2: Comparison of the transconductance of graphene and Si ISFET [16].

Typically, the procedure of transistors fabrication is complicated, including preparation of substrate grown graphene, fabrication of electrode through photolithography and lift-off processes and deposition of source, drain and gate electrode. The most important part of graphene FET fabrication among several steps, is graphene sheet. Quality of 2-dimensional layer has huge effect on sensitivity and performance of biosensor. Fabrication of high-quality graphene in large volumes is vital for high performance and commercial devices. There are several major processes to achieve high quality graphene layer such as chemical vapor deposition (CVD) [17], mechanical exfoliation [18], thermal decomposition [19] and unzipping carbon QDQRWXEHV > @ At its initial discovery, graphene was made with simple scotch tape. In this mechanical exfoliation PHWKRG D Ă&#x20AC;DNH RI JUDSKLWH ZDV SXW RQ D SLHFH RI WDSH and then the tape was stuck together many times, VSUHDGLQJ WKH Ă&#x20AC;DNH RYHU WKH VXUIDFH RI WKH WDSH > @ Since bulk graphite is simply many layers of the hexagonal graphene lattice, when it is spread out over a large area, some spots will be one atom thick and exhibit the properties of graphene. This method produces best quality graphene layer. The primary disadvantage of this method is weak control on layer and small area (<1mm2) production that makes it inappropriate method for mass production [18].

Thermal decomposition of silicon carbide (SiC), although more costly than exfoliation methods, but can make large area graphene layer. As described in recent reviews, one approach is epitaxial growth of graphene layers on the basal faces of single-crystal silicon carELGH KHDWHG WR DERYH Â&#x192;& LQ DQ XOWUDKLJK YDFXXP The resulting graphene layers, which grow as silicon evaporates from the crystal, tend to show various defects such as substrate-induced corrugations [19].

For mass production, full sheet of graphene is necessary. It is achievable by CVD method. This process 7

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Figure 3: Graphene oxide reduction process steps [21].

Table 1: Main methods of producing graphene.

Method

3LRQHHUV

Description

3HHOLQJ 'UDZLQJ

1RYHVHORI HW DO > @

Mechanical exfoliation (repeated peeling) of 3D graphite crystals with Scotch tape.

Epitaxial Growth

Berger et al. [19]

Thermal decomposition of SiC in high vacuum and at high temperature

CVD

/L HW DO > @

Using the atomic structure of a metal substrate to seed the growth of the graphene

Chemical Method

Choucair et al. [21]

A direct chemical synthesis of graphene Nano sheets in a bottom-up approach based on ethanol and sodium reagents.

Unzipping Nanotube

Koshynkin et al. [22]

Unzipping multiwall carbon nanotubes by plasma etching

catalyzes a reaction between substrate and gases under certain conditions [16, 17]. First of all, copper foil loads to containing chamber that is pumped down to SUHVVXUH LQ RUGHU RI P7RUU $IWHU WKDW VPDOO DPRXQW RI K\GURJHQ JDV HQWHUV WKH YDFXXP FKDPEHU DW Â&#x192;& WR UHPRYH FRSSHU R[LGH P7RUU

In the next step, methane gas enters vacuum chamber at higher pressure (6 mTorr). With help of hydrogen gas as a catalyzer, decomposed carbon from methane deposits on copper foil. This reaction begins in isolated areas on the surface of the copper, DQG FRQVWUXFWV QXFOHDWLRQ VLWHV /DWWLFH VWUXFWXUH LV not perfect at these points. Carbon starts to assemble itself hexagonally from these sites until two domains DUH HQFRXQWHUHG 5HDFWLRQ EHWZHHQ PHWKDQH DQG copper foil can no longer occur as soon as the lattice of carbon covers a section of copper. The result is a one-atom thick layer of carbon, which has automatically structured itself into the hexagonal lattice of graphene [22]. So far, we introduced three different method of graphene fabrication. In table.1 main methods are summarized.

Consequently, the graphene has to be removed from 8

the copper and transferred to an insulating substrate. $V GHSLFWHG LQ )LJXUH D OD\HU RI SRO\ PHWK\O PHWK\OSURSHQRDWH 300$ LV VSLQ FRDWHG RQ WKH graphene/copper stack to provide mechanical stability to the graphene layer. This stack is placed on the surface of an iron (III) chloride solution, which etches the copper under the graphene. After diluting, the graSKHQH 300$ OD\HU LV ÂżVKHG RQ WKH ÂżQDO VXEVWUDWH DQG

Figure 4: Graphene transfer process. (a) Graphene is grown via CVD on copper foil. (b) PMMA is spun on top of graphene. (c) Copper foil is removed with an etchant bath. (d) Graphene with PMMA is transferred to Si/SiO2 substrate. (e) PMMA is removed [15].

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 5-13

Figure 5: Graphene FET fabrication process. (a) PMMA Spin Coating on Si/SiO2. (b) Photoresist patterning. (c) Metal deposition and photoresist removing. (d) Graphene growth on Si/SiO2 substrate and PMMA spin coating on it. (e)Graphene channel patterning. (f) Photoresist removing. (g) PMMA spins coating. (h) Electrode patterning. (i) Metal

Figure 6: Transfer characteristics for the graphene tran-

deposition and photoresist removing [23].

sistors before adding DNA, after immobilization with probe DNA, and after reaction with complementary [24].

WKH 300$ LV UHPRYHG E\ GLVVROYLQJ LW LQ VROYHQWV $ ÂżQDO DQQHDOLQJ VWHS FDQ EH XVHG WR IXUWKHU UHPRYH UHVLGXHV IURP WKH 300$ > @ 7R GHÂżQH DFWLYH DUHD DQG FRPSOHWHO\ ÂżQLVK WKH IDErication process of GFET, multiple steps have to be GRQH )LJXUH )LUVW SKRWRUHVLVW KDV WR EH VSXQ RQ 6L 6L22 substrate then patterns for alignment marks. After that, chrome alignment marks have to be deposited via e-beam metal evaporation and remaining metal and photoresist has to strip. In next step, graphene has WR WUDQVIHU WR 6L 6L22 VXEVWUDWH $IWHU 300$ UHPRYing, photoresist has to spin on top of graphene and patWHUQHG *UDSKHQH KDV WR EH UHPRYHG ZLWK 22 plasma etching and remaining photoresist has to be stripped to make channel of device. For creating ohmic metal electrodes, same lithography like channel patterning DQG H EHDP HYDSRUDWLRQ KDV WR EH XVHG > @ After devise fabrication, a passivation layer has to spin coated and patterned on GFET. Channel is the only part of transistor that can be in contact with analyte and metal electrodes has to be insulated. The device have to wire-bonded so can be characterized.

The bonding wires have to cover with silicone glue to insulate them from the analyte [23].

4.GRAPHENE FET BIO APPLICATION a) DNA Sensor 0RKDQW\ HW DO LQ SXEOLVKHG ÂżUVW VLJQLÂżFDQW LQ-

vestigation on graphene and DNA interaction. They VKRZHG WKDW FKHPLFDOO\ PRGLÂżHG JUDSKHQH LV H[FHOlent device for biocellular and bimolecular scale. They have investigated single bacterium and DNA interaction with graphene sheet [23]. First, they had immobilized single strand DNA on graphene sheet. After that, FRPSOHPHQWDU\ '1$ WDJJHG ZLWK Ă&#x20AC;XRUHVFHQW DQG DW the end hybridized with target DNA. They saw this SURFHVV DIIHFWV FXUUHQW DQG HOHFWULFDO ÂżHOG WKDW PDNHV method feasible for DNA sequencing detection. ,Q RWKHU ZRUN 'RQJ HW DO > @ KDYH XVHG WUDQVIHU CVD graphene from Ni substrate to glass to fabricate graphene transistor. Their device detects hybridization of target DNAs to the probe DNAs pre-immobilized RQ JUDSKHQH ZLWK Q0 VHQVLWLYLW\ 7KH\ GHFRUDWed the Au nanoparticles on graphene sheet and could LQFUHDVH XSSHU OLPLW RI GHWHFWLRQ IURP WR Q0 [22]. According to Dong et al. research, device conductance shows amipolar behavior subjecting to applied gate voltage. They have showed that Vg-min is sensitive to probe DNAs immobilization and hybridization. As shown in Figure 6, increasing in analyte concentration shifts minimum gate voltage (Vg-min) to the left and decreases GFET current for the same applied gate voltage.

Chen et al. [23] fabricated low noise GFET on large area graphene. Their GFET sensitivity achieves the concentration as low as to 1 pM. They investigated graphene surface cleanness effect on interaction be9

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Figure 7: Graphene FET array and experimental set up [26].

tween DNA and graphene. They have used gold transIRUPDWLRQ LQVWHDG RI 300$ WR LPSURYH *)(7 HOHFWULFDO SURSHUWLHV > @ Most of methods are using single graphene ISFET RQ FKLS IRU GHWHFWLQJ '1$ VWUDQGV 5HFHQWO\ ;X HW al. [26] have introduced new multiplexed DNA array Graphene ISFET. They have created 8-FET DNA sensor array based on CVD-graphene with maximum senVLWLYLW\ RI S0 ,WV VHQVLWLYLW\ ZDV WLPHV EHWWHU than other state-of-the-art CVD graphene FET [27].

It also better than commercial optical DNA sensing that has sensitivity in order of 1 pM [28]. They have used graphene in two different functions as a site speFLÂżF GHWHFWLRQ RI WDUJHW '1$ DQG DV DQ HOHFWURSKRUHWLF HOHFWURGH IRU VSHFLÂżF VLWH SUREH '1$ LPPRELOL]DWLRQ (Figure 7).

E 3+ 6HQVRU 2QH RI WKH ÂżUVW DSSOLFDWLRQV RI VROXWLRQ JDWHG *)(7 was to sense pH of a solution. First pH sensor was in-

troduced with multilayer graphene sheet as a channel that was grown on SiC substrate [11]. According to that research sensitivity was 99 mV/pH and difference in graphene layer number had almost no effect on sensitivity. Ag/AgCl was used as gate electrode.

Donkerl et al. have used epitaxial graphene on 6H-SiC substrate to fabricate ion solute gate FET array for pH sensing. They have investigated charge carrier mobility and concentration as a function of electrolyte gate potential. They have used UVOLWKRJUDSK\ WR IDEULFDWH XP XP JDWH OHQJWK transistor [29].

Wang et al. have fabricated oxide on graphene bioFET for pH sensing. They passivated graphene chanQHO ZLWK QP 6L22 +I2 UHVSHFWLYHO\ DV D VHQVing/immobilizing and protection layer. In this research VXUIDFH RI 6L22 IXQFWLRQDOL]HG ZLWK $3706 $PLnopropyl) trimethoxysilane) as a pathway for DNA and protein immobilization. They have investigated VHQVLWLYLW\ RI GHYLFH RQ 3%6 3KRVSKDWH EXIIHUHG VDOLQH VROXWLRQ S+ %HVW VHQVLWLYLW\ ZDV P9 S+ > @ .ZDN HW DO > @ KDYH XVHG Ă&#x20AC;H[LEOH *)(7 RQ 3(7 as a glucose sensor. Fabricated sensors sensitivity was LQ WKH UDQJH RI P0 7KLV DFFXUDF\ LV HQRXJK for reference examination or screen test for diabetes diagnostic.

The sensor uses detection of H222 as a function of glucose. They saw that, as the H222 concentration inFUHDVHV L H IURP P0 WR PP WKH 'LUDF SRLQW where the channel conductance is minimized was shifted towards lower value of Vg [31].

In Table 2, voltage sensitivity of different GFET pH sensors report in literature is compared. Main reason for huge difference in sensitivity is not been well unGHUVWRRG XQWLO SUHVHQW EXW GHIHFWV FRQWDPLQDWLRQV and unintentional chemical functionalizations have an important role in GFET quality and so sensitivity.

Table 2: Comparison of graphene PH Sensor sensitivity according to different graphene sheet fabrication process.

Ang et al. [11]

2KQR HW DO > @

Fu et al. [32]

Cheng et al. [33]

Sensitivity (mV/pH)

99

27

6

18

Graphene source

Epitaxial

Exfoliation

CVD

Exfoliation

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Figure 8: Dynamic response of the VG sensor exposed to different concentrations of IgG (a) with and (b) without probe SURWHLQV )RU DOO PHDVXUHPHQWV WKH GUDLQ VRXUFH YROWDJH 9G ZDV Âż[HG DW RU 9 F &RPSDULVRQ RI WKH VHQVRU VHQsitivity in response to complementary IgG (2 ng/mL), mismatched IgM (0.2 mg/mL), and mismatched HRP (0.2 mg/mL).

(UURU EDUV ZHUH REWDLQHG IURP ÂżYH VDPSOHV WHVWHG IRU HDFK DQDO\WH > @

c) Protein Sensor GFETs, because of their large area and high mobility are really excellent device for protein, anti body and antigen detection. In recent years, there has been lots of research for improving sensitivity of GFET biosenVRUV ,Q D UHFHQW UHVHDUFK 0DR DQG KLV FRZRUNHUV > @ investigated vertically aligned graphene FET grown on JROG HOHFWURGH ZLWK 3(&9' PHWKRG 7KH VHQVRU VHQsitivity was 12 pM and showed really good selectivity for Immunoglobulin G (IgG) protein. They showed that vertically-oriented graphene (VG) facilitates the deposition of gold nanoparticle-antibody conjugates on transistor. In other work they showed that attaching

gold nanoparticle-antibody will decrease transistor current. They have used thermally reduced graphene FET to investigate immune system of human body.

Binding of antibody and antigen can be detected with I-V characteristics of vertically aligned GFET (FigXUH > @ 2NDPRWR HW DO XVHG JUDSKHQH Ă&#x20AC;DNH DV D channel for GFET for detection of heat shock protein +63 7KH\ FRXOG UHDFK JRRG VHQVLWLYLW\ RI S0 In other work, Kim et al. reported self aligned reduced graphene oxide FET for label free detection of

Figure 9: Schematic of R-GO FET fabrication and detection

Figure 10: Current-gate voltage characteristic (I-VG) of gra-

of PSA-ACT complex. (a) Self-assembly of GO nanosheet.

phene FET after each step required for functionalization with

(b) Formation of Ti/Au source and drain electrodes. (c)

fusion protein GST-BT5: as prepared (black), after diazoni-

Functionalization of R-GO channel by linker molecules. (d)

um treatment (red dashed), after Ni-NTA attachment (green

Illustration of R-GO FET immunosensor with Pt reference

dotted), and after incubation in protein (GSTBT5) solution

electrode in the analyte solution [36].

(blue dot-dash) [36].

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prostate cancer [36]. They showed that analyte concentration has linear effect on gate minimum voltage DQG FRQGXFWLYLW\ 7KH\ XVHG 36$ $&7 RQ WR GLIIHUHQW S+ HQYLURQPHQW )RU S+ LQFUHDVLQJ LQ DQDO\WH concentration makes Vg-min shift to left and for pH= 6.2, increasing in analyte concentration results in Vg-min shift to right. In addition to gate voltage, conductivity LQFUHDVHV IRU S+ DQG GHFUHDVHV IRU S+ ZLWK analyte concentration increase (Figure 9). /X HW DO > @ UHSRUWHG UREXVW PHWKRG WR ELQG SRO\hictidine-tagged protein to graphene FET and used Ă&#x20AC;XRUHVFHQW SURWHLQ WR LQYHVWLJDWH SKRWRHOHFWULF HIfect in device. They have applied three different light EHDPV ZLWK DQG QP ZDYH OHQJWK 7KH\ VDZ WKDW RQO\ QP OLJKW KDV LPSDFW RQ , 9 FKDUDFWHULVWLFV RI GHYLFH 7KH\ VDZ VLJQLÂżFDQW , 9G shift is observed only for violet illumination, with negligible change for green or red light. They conclude that curUHQW GHFUHDVH PD\ UHĂ&#x20AC;HFW D QHW GLSROH DVVRFLDWHG ZLWK FKDUJH UHGLVWULEXWLRQ LQ *)3 XSRQ SKRWR H[FLWDWLRQ RU *)3 *)(7 FKDUJH WUDQVIHU VLQFH *)3 LV UHSRUWHG WR EH D OLJKW LQGXFHG HOHFWURQ GRQRU )LJXUH > @ ,W can be concluded that GFETs device may be superior to electrode device in certain aspect.

5. CONCLUSIONS In this review, fabrication, characterization and application of GFET has been discussed in biosensor deYLFH DSSOLFDWLRQ 2XU IRFXV ZDV LQ '1$ DQG SURWHLQ detection for new methods of cancer detection. Due to excellent electrical and mechanical properties like high carrier mobility and capacity graphene has shown really amazing exclusivity in bio area. Along with its great results, GFET has shown numerous challenges for mass production. First one is large area production of high quality graphene. Nowadays most promising method to achieve high surface area graphene is CVD method. Another challenge is graphene tendency to absorb hydrocarbons that contaminates the surface of GHYLFH DQG GHJUDGHV LWV SHUIRUPDQFH 2QH RI WKH IDEULcation steps that introduce contamination in graphene VKHHW LV OLWKRJUDSK\ 3KRWRUHVLVW LV WKH PDLQ UHDVRQ of contamination in this step. With these advantages consideration, it is obvious that graphene will brings 12

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amazing future for electronic and biosensor future application.

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31. Kwak Y.H., Choi D.S., Kim Y.N., Kim H., Yoon D.H., Ahn S.S., Seo S., Biosens Bioelectron, 37

)X : 1HI & .QRSIPDFKHU 2 7DUDVRY $ Weiss M., Calame M., Scheonenberger C., Nano Lett., 11

&KHQJ = /L 4 /L = =KRX 4 )DQJ < Nano Lett., 10

0DR 6 <X . &KDQJ - 6WHHEHU ' $ 2FROD / ( &KHQ - Sci. Rep., 3

0DR 6 <X . /X * &KHQ - Nano Res., 4

.LP ' - 6RKQ , < -XQJ - + <RRQ 2 - /HH 1 ( 3DUN - 6 Biosens Bioelectron, 41

621. /X < /HUQHU 0 % 4L = - 0LWDOD -U - - /LP J.H., Discher B.M., Johnson A.C., Appl. Phys.

Lett., 100

13

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Synthesis Silver Nanoparticles by Recovery Silver from Anode Slime of Kerman Sarcheshmeh Cooper Complex Hojat Zahedi1, Afsaneh Mollahosseini2*, Ebrahim Noroozian3 1 2

M.Sc., Department of Chemistry, Iran University of Science and Technology, Tehran, Iran

Assistant Professor, Department of Chemistry, Iran University of Science and Technology, Tehran, Iran 3

Associate Professor, Department of Science, Shahid Bahonar University of Kerman, Kerman, Iran

5HFHLYHG 2FWREHU $FFHSWHG 'HFHPEHU

ABSTRACT $FFRUGLQJ WR FLUFXPVWDQFH RI NHUPDQ VDUFKHVKPHK FRRSHU FRPSOH[ WKDW LWV DQRGH VOLPH LV PDLQO\ FRQVLVWHG RI &X $J $X 3E DQG 6H ,Q WKLV ZRUN UHFRYHU\ RI VLOYHU IURP DQRGH VOLPH DQG VXEVHTXHQW V\QWKHVLV RI VLOYHU QDQRSDUWLFOHV IURP OHDFKLQJ VROXWLRQ ZDV PDGH 6LOYHU ZDV VHSDUDWHG IURP DQRGH VOLPH E\ XVLQJ RI +123 DQG +&O ; 5D\ Ã&#x20AC;XRUHVFHQFH VSHFWURVFRS\ ;5) ZDV XVHG WR FKDUDFWHUL]H DQRGH VOLPH FRPSRQHQWV 6LOYHU QDQRSDUWLFOHV 613V ZLWK DYHUDJH VL]H RI QP ZHUH REWDLQHG WKURXJK VRQLFDWLRQ DTXHRXV VROXWLRQ RI VLOYHU QLWUDWH LQ WKH SUHVHQFH RI GH[WURVH DQG SRO\YLQ\O S\UUROLGRQH 393 DV UHGXFWLRQ DQG VWDELOL]LQJ DJHQW UHVSHFWLYHO\ 613V ZHUH FKDUDFWHUL]HG E\ VXUIDFH SODVPRQ UHVRQDQFH 635 DQG 8OWUDYLROHW 9LV LEOH 89 9LV VSHFWUXP ; 5D\ GLIIUDFWLRQ ;5' SDWWHUQ FRQ¿UPHG WKH FXELF PRUSKRORJ\ RI PHWDOOLF 613V DQG HQHUJ\ GLVSHUVLYH ; 5D\ VSHFWURVFRS\ ('6

VSHFWUXP VKRZHG SHDNV RI VLOYHU IUHH RI LPSXULW\ 6L]H DQG GLVWULEXWLRQ RI 613V ZHUH GHWHUPLQHG E\ G\QDPLF OLJKW VFDWWHULQJ DQDO\VLV '/6 DQG VFDQQLQJ HOHFWURQ PLFURVFRS\ 6(0

Keyword: 6LOYHU 1DQRSDUWLFOHV 6RQL¿FDWLRQ .HUPDQ 6DUFKHVKPHK &RRSHU &RPSOH[ $QRGH 6OLPH /HDFKLQJ 1DQRWHFKQRORJ\

1. INTRODUCTION Nanotechnology has had an immense impact on nearly DOO H[LVWLQJ VFLHQWL¿F GLVFLSOLQHV 1DQRSDUWLFOHV KDYH unique physiochemical and optical properties due to VXUIDFH DQG ¿QLWH VL]H HIIHFW 0HWDO QDQRSDUWLFOHV DUH DW the top of the rapidly increasing list of materials being investigated in the nanostructured [1]. In recent years, UHVHDUFKHUV LQ WKH ¿HOG RI QDQRWHFKQRORJ\ DUH ¿QGLQJ that there is an expanding research in the synthesis of (*) Corresponding Author - e-mail: amollahosseini@iust.ac.ir

613V GXH WR WKH SRWHQWLDO DSSOLFDWLRQ IRU WKH GHYHORSment of novel technologies [1, 2] Silver nanoparticles 613V KDYH EHHQ SDLG HQRUPRXV DWWHQWLRQ LQ YDULRXV areas, such as, catalysts [2], because of their morphology play important role in controlling the physical, chemical, optical, and electronic properties of these nanoscopic materials [3]. In this work, copper anode slime of Kerman Sarcheshmeh cooper complex that

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19

is in south east of Iran was under analyzing. Anode Slime is characterized by higher amount of Ag, Se, 3E DQG &X FRPSDUHG WR RWKHU PHWDOV ZLWK YHU\ ORZ amount of Au. There is interest in studying methods for recovery of these metals from anode slime. Impurities must also be removed from anode slime before UHFRYHU\ RI YDOXDEOH PHWDOV OLNH $J > @ 8VLQJ RI chemical route, since discovered, has been studied for yielding kinds of nanomaterials, especially noble metal nanoparticles, such as silver, gold and platinum [6, 7]. Among these researches, chemical method under sonication has been applied widely due to the relatively high reductive ability of it [8, 9].

Mollahosseini A at al

separated from the solution by vigorous centrifugation DW USP IRU PLQ WR UHPRYH DQ\ H[FHVV SURWHFWing agent and then re-dispersed in distilled water. In RUGHU WR REWDLQ 613V SRZGHU WKH VLOYHU FROORLGV ZHUH VHW LQ RYHQ DW Â&#x192;& IRU KRXUV WR VROYHQW HYDSRUDWLRQ $Q XOWUDVRQLF EDWK (/0$ +] 8OWUDYLROHW 9LV LEOH 89 9LV 7 ; 5D\ Ă&#x20AC;RXUFHQFH VSHFWURVFRS\ $5/ ;5) ; 5D\ SRZGHU GLIIUDFWLRQ ;5'

3: DQG HQHUJ\ GLVSHUVLYH ; 5D\ VSHFWURVFRS\ ('; ;*7 ZHUH XVHG WR SUHSDUDWLRQ DQG FRQÂżUPDWLRQ WKH PRUSKRORJ\ DQG SXULW\ RI PHWDOOLF 613V 6L]H DQG GLVWULEXWLRQ RI 613V ZHUH GHWHUPLQHG E\ G\QDPLF OLJKW VFDWWHULQJ DQDO\VLV '/6 =(1 DQG scanning electron microscopy (SEM) SBC12.

2. EXPERIMENTAL 3. RESULTS AND DISCUSSION 0DWHULDOV XVHG LQ WKH V\QWKHVLV RI 613V LQYROYHG QLWULF DFLG K\GURFKORULF DFLG DPPRQLD GH[WURVH sodium hydroxide and polyvinyl pyrrolidone were obtained from Merck.

All glassware were washed with deionized water DQG GULHG EHIRUH XVH $Q DOLTXWH RI J DQRGH VOLPH ZDV XVHG LQ H[SHULPHQW P/ QLWULF DFLG ZDV DGGHG WR J DQRGH VOLPH $IWHU ÂżOWHULQJ P/ +&O ZDV added and AgCl was obtained from the leach solution.

Silver chloride was collected and dissolved in ammoQLD VROXWLRQ 0 DQG WKLV VROXWLRQ DQG ZW SYS ZDV PL[HG LQ URRP WHPSHUDWXUH DQG 1D2+ ZDV DGGHG drop by drop for obtain pH 12. In this time solution FRORXU FKDQJH WR \HOORZ $IWHU PLQ VROXWLRQ RI GH[WURVH 0 UDSLGO\ ZDV DGGHG DQG FRORXU FKDQJHG from yellow to dark brown. This solution immediately was transferred to ultrasonic bath and sonicated for PLQ DW Â&#x192;& 7KH REWDLQHG VLOYHU FROORLGV ZHUH

In order to characterize silver percent in anode slime, ;5) DQDO\VLV ZDV DSSOLHG DQG WKH REWDLQHG UHVXOW VKRZHG WKDW DERXW DQRGH VOLPH LV $J22 To separate silver from anode slime, acid leaching was used. The anode slime was leached with nitric DFLG DW Â&#x192;& ,Q WKLV FRQGLWLRQ &X 3E 6H LV OHDFKHG DV well as Ag. In order to Ag separation from other component, HCl was added and silver was precipitated as $J&O DQG 3E&O2 that both of them were white solid.

3E&O2 was removed by washing hot water. $QRGH V OLP H +123 o $J123 &X 123 2 3E 12 6H 12 2WKHU VROLG

(1)

$J 2 2 +123 o $J123 + 2 2

(2)

&X2 +123 o &X 123 2 + 2 2

(3)

Table 1: XRF analysis of anode slime.

16

Composition

:HLJKW

Composition

:HLJKW

Composition

:HLJKW

Al223

As223

Fe223

7H22

6L22

2.6

6H22

13.7

Ag22

3.8

Sb223

6Q22

Au

/D2

1

Cl

&X2

7.2

6U2

&D2

3E2

3.6

%D2

37.32

622

22.7

Mollahosseini A at al

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19

Figure 1: UV-Vis absorption spectra for SNPs powder without sonication and after sonication with 2 hours.

3E2 +123 o 3E 123 2 + 2 2

6H2 +12 o 6H 12 + 2

1LWUDWH VROXWLRQ +&O o $J&O 3E&O2

(6)

$J&O 3E&O2 :DVKLQJ ZLWK KRW ZDWHU o 2QO\ $J&O p (7) AgCl 2NH 3 o [Ag(NH 3 ) 2 ]Cl

(8)

$J 1+ 3 2 393 o $J 393 1+ 3

(9)

&+ 2+ &+2+ &+2 $J 393 2+ o

&+2+ &+2+ &22+ $J 393 + 2

&+ 2+ &+2+ &+2 $J 2+ o &+2+ &+2+ &22+ $J + 2

(11)

According to previous study alkaline solution for synWKHVLV RI 613V LV PRUH HIIHFWLYH WKDQ SXUH VROXWLRQ > @ $V 2+- injected to solution makes accelerate the reaction and help dextrose and pvp to converted

Ag+ WR $JÂ&#x192; PRUH DQG EHWWHU 7R VWXG\ WKH DEVRUEDQFH RI 613V LQ 89 9LV VSHFWUXP '56 LV DSSOLHG 7KHUH LV D EDQG DURXQG QP WKDW LV UHODWHG WR 613V Scanning electron microscopy (SEM) image in )LJXUH FRQÂżUPHG WKH PRUSKRORJ\ RI 613V QDQRVWUXFWXUH 6(0 LPDJHV VKRZHG WKDW WKH VL]H RI 613V in nanosize and their spherical morphology that was prepared by this method. '/6 SORW VKRZHG WKH GLVWULEXWLRQ RI 613V IRU VDPSOH LQ )LJXUH 5HVXOW VKRZHG WKDW 613V LQ UDQJH RI QP '/6 SORW IRU VL]H GLVWULEXWLRQ RI 613V E\ YROXPH LQ )LJXUH ZDV VKRZQ WKDW WKH UHODWLRQ EHWZHHQ QXPEHU of particles and volume of particles that was occupied.

7KLV UHODWLRQ ZDV GLUHFWO\ GXH WR RXU 613V ZDV VSKHUical and the formula of spherical volume that is V= ŕ­&#x17E; U3, so as particles in a space or volume be more

Table 2: Band Gap Energy.

K 3ODQNV FRQVWDQW

[ Joules

C = Speed of light

[ 8 meter/sec

Č&#x153; &XW RI ZDYHOHQJWK

[ -9 meter

( K & Č&#x153;

[ -19 Joules

H9 [ -19

3.21 eV

Figure 2: SEM image of SNPs after 2 hours sonicating.

17

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19

Mollahosseini A at al

Figure 3: DLS analysis for SNPs size distribution by number.

Figure 4: DLS analysis for SNPs size distribution by volume.

the plot of these particles is more too. For this reason DQG WKH YROXPH LQ UDQJH RI WLOO QP LV ELJJHU WKDQ RWKHUV EHFDXVH WKH QXPEHU RI 613V LQ WKLV UDQJH is more.

Energy dispersive spectroscopy (EDS) was used to analyze the chemical composition of a material. EDS IRU 613V IURP SRZGHU VDPSOHV VKRZQ LQ )LJXUH WKH peak of silver in their plot in 3, 23 and 26 KeV. The SXULW\ RI VLOYHU ZDV VKRZQ LQ 7DEOH WKDW ZDV 18

Figure 5: EDS spectra for SNPs under 2 hours sonicated.

Mollahosseini A at al

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19

Table 3: Output results of EDS analysis of SNPs under 2 hours sonicate.

Elem.

/LQH

0DVV

$WRPLF

Intensity

Formula

0DVV

16 S 22 Ti 26 Fe

K K K

2.12

1.77

S 7L22 Fe223

29 Cu

K

3.31

&X2

6H

K

7.83

6H22

$J

K

97.39

Ag

3E

/

3E

3.77

2

QRWLFHDEOH IRU V\QWKHVL]H RI 613V ; 5D\ GLIIUDFWLRQ ZDV XVHG WR LGHQWLI\ FU\VWDOOLQH SKDVHV )LJXUH VKRZV ; 5D\ GLIIUDFWLRQ SDWWHUQV RI WKH SRZGHU 0RUSKRORJ\ RI 613V ZHUH FXELF WKH H[KLELWHG SLFNV FRUUHVSRQG WR WKH DQG LQ ÔŚ DQG RI D FXELF VWUXFWXUH LV LGHQWLÂżHG E\ XVLQJ RI the standard data.

4. CONCLUSIONS In summary in this work leaching of anode slime showed that almost all of silver could be separated IURP DQRGH VOLPH E\ QLWULF DFLG 613V ZDV \LHOGHG ZLWK KLJK SXULW\ DW Â&#x192;& XQGHU VRQLFDWLRQ ZLWK using of dextrose and pvp in the role of reduction and VWDELOL]HU QP GLDPHWHU 613V ZHUH REWDLQHG the concentration of silver cation in proportion to the concentration of pvp was kept constant during all the H[SHULPHQWV 2+ KDV WKH HIIHFWV RI KHOSLQJ WR \LHOG the nucleation sites and acting as surfactant. This FRPELQHG PHWKRG WR V\QWKHVL]H 613V KDYH VPDOO GLDPHWHU DQG EHWWHU SXULW\ RI 613V LW FDQ EH DSSOLHG LQ fabricating composite because of simple process and condition.

ACKNOWLEDGEMENT :H DUH JUDWHIXO IRU WKH ÂżQDQFLDO VXSSRUW IURP 5Hsearch Council of Kerman Sarcheshmeh Copper Complex and Iran University of Science and Technol-

ogy (IUST).

REFERENCES %DUGDMHH * 5 3RXUMDYDGL $ 6RO\PDQ 5 3rd Conference on Nanostructures .LVK ,VODQG , 5 ,UDQ

2. Khaleghi A., Ghader S., Afzali D., Int. J. Mining Sci. Technol., 24

3. Das S., Motiarkhan M., Guha A., Das A., Mandal A., Bioresource Technol., 124

5LPDO ,VDDF 5 6 6DNWLYHO * 0XUWK\ & J. Nanotechnology, 6

&KDRGRQJ + /DQODQ / =HJXR ) -LD / -LQEDR G., Jie W., Ultrason. Sonochem., 21

/X < & &KRX . 6 J. Chin. Inst. Chem. Eng., 39

.KDQ = 6LQJK 7 +XVVDLQ - <RXVLI 2EDLG $ $/ 7KDEDLWL 6 0RVVDODP\ ( + Colloids surf.

B, 102

8. Norouzi M., Soleimani M., National Conference on Nanotechnology and Green Chemistry, Tehran, ,UDQ

&KRX . /X < /HH + Mater. Chem. Phys., 94

6LQJK 0 6LQJK $ . 0DQGDO 5 . 6LQKD , Colloids Surf. A: Physicochem. Eng. Aspects, 390

:DQJ + 4LDR ; &KHQ - :DQJ ; 'LQJ 6 Mater. Chem. Phys., 94

/HL 6 /LQ / )DQJ[LDR - -LDQPLQ 6 Catal. Sci. Technol., 4

19

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 21-24

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials ,QÃ&#x20AC;XHQFH RI 6ROXWLRQ 7HPSHUDWXUH DQG S+ RQ 6L]H DQG Morphology Improvement of Chitosan Nanoparticles as Protein Delivery Vehicles Nasim Kiaie1, Rouhollah Mehdinavaz Aghdam2*, Hossein Ahmadi Tafti3**, Shahriyar Hojati Emami4, Jalal Izadi Mobarakeh5 1

M.Sc., Department of Tissue Engineering, AmirKabir University of Technology, Tehran, 15875, Iran 2

Ph.D., Tehran Heart Hospital Research Center & Nanotechnology Department, Space Transportation Research Institute, Tehran, Iran 3

Professor, Tehran Heart Hospital Research Center, Tehran, Iran

4

Ph.D., Department of Tissue Engineering, AmirKabir University of Technology, Tehran, 15875, Iran

5

Ph.D., Department of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, 13164, Iran

5HFHLYHG 1RYHPEHU $FFHSWHG -DQXDU\

ABSTRACT ,Q UHFHQW \HDUV XWLOL]DWLRQ RI FKLWRVDQ WULSRO\SKRVSKDWH QDQRSDUWLFOHV KDV EHHQ FRQVLGHUHG JUHDWO\ DV SURWHLQ GHOLYHU\ YHKLFOHV (IIHFWV RI D YDULHW\ RI IDFWRUV RQ ¿QDO FKDUDFWHULVWLFV RI QDQRSDUWLFOHV KDYH EHHQ VWXGLHG E\ PDQ\ LQYHVWLJDWRUV $OWKRXJK WKH REMHFWLYH RI WKLV VWXG\ ZDV WR DFKLHYH VPDOOHU FKLWRVDQ QDQR FDUULHUV YLD FKDQJLQJ IDEULFDWLRQ SDUDPHWHUV VXFK DV S+ DQG WHPSHUDWXUH DQG WR HOXFLGDWH WKHLU HIIHFW RQ WKH VL]H DQG SRO\GLVSHUVLW\ RI QDQRSDUWLFOHV 1DQRSDUWLFOHV ZHUH SURGXFHG E\ LRQLF JHOODWLRQ PHWKRG DQG SDUWLFOH¶V PRUSKRORJ\ ZDV VKRZQ E\ ¿HOG HPLVVLRQ VFDQQLQJ HOHFWURQ PLFURVFRS\ )( 6(0 7KH UHVXOWV VKRZ WKDW ZLWK LQFUHDVLQJ S+ YDOXH IURP WR HLWKHU SRO\ GLVSHUVLW\ RU K\GURG\QDPLF GLDPHWHU GHFUHDVHG VLJQL¿FDQWO\ LQ D OLQHDU WUHQG 5 IRU VL]H DQG IRU SG, GDWD 5HVXOWV RI WKLV VWXG\ FRXOG EH XVHG IRU SUHSDULQJ SURWHLQ ORDGHG FKLWRVDQ QDQRSDUWLFOHV ZLWK VPDOO VL]HV LQ WKH UDQJH RI EHORZ QDQRPHWHUV ZKLFK LV V\PSDWKHWLF IRU GUXJ GHOLYHU\ DSSOLFDWLRQV

Keyword: +\GURG\QDPLF GLDPHWHU 3URWHLQ &KLWRVDQ 3RO\PHULF QDQRSDUWLFOHV ,RQLF JHODWLRQ

1. INTRODUCTION Biodegradable polymeric nanoparticles have attracted interests in a broad range of applications in nanotechnological devices. They could be utilized as peptide and protein delivery vehicles and desirably preserve WKHLU DFWLYLW\ WKURXJK UHVWULFWLQJ SHUPHDWLRQ RI VSHFL¿F enzymes into polymeric matrix.

In drug delivery systems having a monodisperse colloid of nanoparticles or achieving minimum polydis-

SHUVLW\ LV RI RXWPRVW VLJQL¿FDQFH WR NHHS GUXJ UHOHDVH UDWH FRQVWDQW $GGLWLRQDOO\ SDUWLFOH VL]H FDQ LQÃ&#x20AC;XHQFH the nanoparticle distribution and thus bioavailability.

The sizes of nanoparticles determine their penetration into cell membranes, binding and stabilization of proteins, and lysosomal escape after endocytosis. They are also better suited for intravenous (i.v.) delivery.

Chitosan, a linear aminopolysaccharid composed

&RUUHVSRQGLQJ $XWKRU H PDLO PHKGLQDYD]#DXW DF LU &R &RUUHVSRQGLQJ $XWKRU H PDLO DKPDGLWD#VLQD WXPV DF LU

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 21-24

Table 1: Samples and experiments conditions.

Sample

pH

pdI

A B C

6

Hydrodynamic diameter (nm)

Ch concentration 0.16% (w/v), BSA concentration 0.88% (w/v, Ch:TPP 5, solution temperature 60°C. R2= 0. 94for size and R2= 0.99 for polydispersity.

RI UDQGRPO\ GLVWULEXWHG OLQNHG G JOXFRVDPLQH and N-acetyl-d-glucosamine units, gained increased attention for drug delivery systems in view of its biocompatibility, non toxicity, low immunogenicity, biodegradability and cationic properties [1-3].

Several methods have been used for chitosan particle preparation including emulsion, ,solvent evaporation, iontotropicgellation, spray drying, reverse micelODU FRDFHUYDWLRQ DQG FLHYLQJ PHWKRGV > @ $PRQJ the mentioned methods, ionic gellation method has JDLQHG VLJQLÂżFDQW PRPHQWXP IRU WKH SXUSRVH RI SURtein delivery because of non toxicity, being organic solvent free controllablity, being convenient, mild and in a sense protein friendly [6]. In this method, interaction of amino groups of chitosan with negatively FKDUJHG SKRVSKDWHV RI WULSRO\SKRVSKDWH 733 LV UHsponsible for ionic crosslinking [7].

Nanoparticle formation seems to be very sensitive to processing conditions such as ambient and chitosan solution temperature [6, 8], stirring rate [6, 8], ultrasonic exposure [8], crosslinking time [9], molecular weight, degree of deacetylation and concentration of FKLWRVDQ > @ FKLWRVDQ WR 733 PDVV UDWLR 3(* DGGLWLRQ > @ GUXJ FRQFHQWUDWLRQ > @ 733 FRQcentration [6, 9, 16 and 17], pH of chitosan solution > DQG @ DQG DFHWLF DFLG FRQFHQWUDWLRQ [16]. This paper will focus on varying processing conditions in order to achieve the best morphology and size of nanoparticles made from chitosan as peptide delivery vehicles.

2. MATERIALS AND METHOD 0HGLXP PROHFXODU ZHLJKW FKLWRVDQ GHDFHW\ODW22

Mehdinavaz Aghdam R et al

HG FS VRGLXP WULSRO\SKRVSKDWH DFHWLF DFLG and BSA were purchased from Sigma-Aldrich chemiFDO &R /WG 1DQR FKLRVDQ ZDV SURGXFHG XVLQJ DQ LRQLF JHODWLRQ PHWKRG > @ We determined the hydrodynamic diameter of QDQRSDUWLFOHV XVLQJ D =HWDVL]HU 1DQR =6 0DOYHUQ Instruments, UK).

The shape and morphology of the nanoparticles ZHUH REVHUYHG E\ ÂżHOG HPLVVLRQ VFDQQLQJ HOHFWURQ PLFURVFRS\ )( 6(0 3KLOLSV ;/ Âą1HWKHUODQGV

P/ RI QDQRSDUWLFOHV VXVSHQVLRQ ZDV WKLQO\ VSULQkled onto a glass slide and after complete drying was mounted on an SEM stub and sputter-coated with gold in an argon atmosphere. The coated samples were exDPLQHG E\ 6(0 &KLWRVDQ VROXWLRQV RI Z Y

were prepared in acetic acid aqueous solution at room temperature and stirred for 2 h at high speed to obWDLQ D FOHDU GLVSHUVLRQ Z Y %6$ ZDV DGGHG WR FKLWRVDQ VROXWLRQ DQG VWLUUHG ZHOO 733 VROXWLRQ PJ P/ ZDV DGGHG GURS ZLVH ZLWK &KLWRVDQ WR 733 UDWLR RI 7KHVH VROXWLRQV ZHUH NHSW XQGHU FRQVWDQW PDJQHWLF VWLUULQJ USP IRU PLQ $OO RI WKH solutions were ultralsonicated for 1 min and formed nanoparticles were concentrated by centrifugation at USP RQ D P/ JO\FHURO EHG Â&#x192;& PLQ

and were re-suspended in ultrapure water.

3. RESULTS AND DISCUSSION As it is mentioned before, size and polydispersity of nanoparticles are important for drug delivery sysWHPV /RDGLQJ GUXJV VSHFLDOO\ PDFURPROHFXOHV VXFK as proteins leads to higher amounts of size. Control of process parameters such as chitosan concentration, GUXJ FRQFHQWUDWLRQ DQG FKLWRVDQ WR 733 UDWLR FRXOG GHFUHDVH WKH ÂżQDO VL]H ,Q WKLV VWXG\ ZH NHSW FKLWRVDQ WR 733 UDWLR FRQVWDQW ZKLOH PDGH FKDQJHV LQ S+ DQG FKLWRVDQ VROXWLRQ WHPSHUDWXUH 5HVXOWV DUH VKRZQ LQ 7Dble 1. It is evidence from Table 1 that with increasing pH more compact and smaller nanoparticles formed.

Also, polydispersity values were reduced with increasing pH amounts.

Noteworthy, achieving narrow distribution for chiWRVDQ QDQRSDUWLFOHV LV GLIÂżFXOW VLQFH FKLWRVDQ LV FRPposed of a wide distribution of low, medium and high

Mehdinavaz Aghdam R et al

D:' QP nm

) QP F:

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 21-24

E:( QP nm

G:* QP nm

Figure 1: Effect of chitosan solution temperature on hydrodynamic diameter. Ch concentration 0.16% (w/v), BSA concentration 0.88% (w/v), Ch:TPP 5. D and E at pH= 4.5, F and G at pH= 6.

molecular weights.

This observation stems from ionic gellation concept.

In this process, electro-positive amino hydrogen of FKLWRVDQ DQG WKH HOHFWUR QHJDWLYH DQLRQ RI 733 OLQN each other electrostatically [11] admittedly, increasing pH may decrease protonation of molecules. In conclusion, less NH3+ Binding sites on chitosan molecules exist.

Also, Mi et al. [12] illustrated that in the aqueous 733 VROXWLRQ WKHUH H[LVW WULSRO\SKRVSKRULF LRQV VXFK DV 332 Ă­, H2332 Ă­ DQG +332 Ă­ varying according to pH alterations in solution. pH increase leads to

OHVV ELQGLQJ RI SRO\SKRVSKRULF LRQV WR FKLWRVDQ 7KXV smaller nanoparticles are formed.

In higher solution temperatures viscosity of chitosan increase and consequently molecules approach each other, attractive forces get on the top of repulsive ones between NH3+ sites causing small and compact nanoparticles as it is presented in Figure 1.

In this study, morphology of nanoparticles as it is depicted in Figure 2 is favorably smooth and spherical in shape which is in accordance with Brittoâ&#x20AC;&#x2122;s results [13].

In this picture spherical nanoparticles are ranging 23

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 21-24

Mehdinavaz Aghdam R et al

(chitosan solution temperature and pH increasement) might have a linear relationship with size and narrow down polydispersity. Seemingly, we are able to present that nanoparticles morphologies were spheriFDO DQG SRO\ GLVSHUVLW\ UDQJHG LQ WR DURXQG DQG PHDVXUHG K\GURG\QDPLF GLDPHWHU UDQJHG LQ WR QP 7KLV VWXG\ FRXOG EH XVHG IRU UHDFKLQJ D favorable size in the case of protein loaded chitosan nanoparticles.

D

E

Figure 2: Above: SEM picture of nanoparticles at pH= 4.5 and solution temperature of 25°C. Below: FE-SEM of nanoparticles at pH= 6 and solution temperature of 60°C. (Chitosan concentration 0.16% (w/v), BSA concentration 0.88% (w/v), Chitosan: TPP= 5).

IURP WR QP ,Q VRPH FDVHV ELJJHU VSKHUHV of clusters of several nanoparticles comes into beLQJ 3LFWXUHV ZLWK KLJK PDJQLÂżFDWLRQV JLYH PRUH GHtails of these features. It is evident that The size of the nanoparticles based on the FE-SEM micrographs DUH VPDOOHU WKDQ WKH VL]H 0HDVXUHG E\ '/6 EHFDXVH the second is hydrodynamic diameter which is larger due to the ability of chitosan to swell in contact with ZDWHU ZKLFK LV GLVSHUVDQW SKDVH LQ '/6 H[SHULPHQWV > @

4. CONCLUSIONS According to our study it shows that varying the SUHSDUDWLRQ FRQGLWLRQV RI FKLWRVDQ 733 QDQRSDUWLFOHV

REFERENCES 1. Kumari A., Yadav S. K., Yadav S.C., Colloids Surf., B., 75

2. Amidi M., Mastrobattista E., Jiskoot W., Hennink W.E., Adv. Drug Delivery Rev., 62

6LQKD 9 5 6LQJOD $ . :DGKDZDQ 6 .DXVKLN 5 .XPULD 5 %DQVDO . 'KDZDQ 6 Int. J. Phytorem., 274

$JQLKRWUL 6 $ 0DOOLNDUMXQD 1 1 $PLQDEKDYL T. M., J Control Release, 100

3DUN - + 6DUDYDQDNXPDU * .LP . .ZRQ , C., Adv. Drug Delivery Rev., 62

)DQD : <DQ : ;XE = 1L + Colloids Surf., B., 90

%RGPHLHU 5 &KHQ + * 3DHUDWDNXO 2 Pharm.

Res., 6

7VDL 0 / %DL 6 : &KHQ 5 + Carbohydr.

Polym., 71

.R - $ 3DUN + - +ZDQJ 6 - 3DUN - % /HH J.S., Int. J. Pharm., 249

&DOYR 3 5HPXQDQ /RSH] & 9LOD -DWD - / Alonso M. J., Pharm. Res., 14

11. Sun Y., Wan A., J. Appl. Polym. Sci., 105

0L ) / 6K\X 6 6 /HH 6 7 :RQJ 7 % J. Polym. Sci. Part B: Polym. Phys., 37

'H %ULWWR ' 'H 0RXUD 0 5 $RXDGD ) $ 0DWWRVRD / + & $VVLV 2 % * Food Hydrocolloid, 27

3DSDGLPLWULRX 6 $ $FKLOLDV ' 6 %LNLDULV ' 1 Int. J. Pharm., 430

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Synergistic Effects of Taxus baccata Extract Mixtures with Silver Nanoparticles against Bacteria and Fungal Mehrorang Ghaedi1 0DVRPHK <RXVH¿ 1HMDG2, Leila Delshad3* 1 2

Professor, Department of Chemistry, Yasouj University, Yasouj , Iran

Assistant Professor, Department of Biology, Yasouj University, Yasouj , Iran 3

M.Sc. Department of Chemistry, Yasuj University, Yasouj, Iran

5HFHLYHG 1RYHPEHU $FFHSWHG -DQXDU\

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axus baccata L. ,Q WKLV VWXG\ WKH XVH ZLWK +\GURDOFRKOLF H[WUDFW Taxus baccata L. RI PHWKRG PDFHUDWLRQ VRDNLQJ ZDV SUHSDUHG $OVR DQWLEDFWHULDO DQWLIXQJDO DFWLYLWLHV RI &RPSRXQGV H[WUDFW $J13V PL[WXUH RI H[WUDFW ZLWK $J13V ZHUH WHVWHG DJDLQVW WKUHH *UDP QHJDWLYH EDFWHULD Escherichia coli $7&& Acinetobacter baumannii $7&& DQG Klebsiella pneumoniae $7&& DQG *UDP SRVLWLYH EDFWHULD Staphylococcus aureus $7&& DQG DOVR IXQJL Aspergillus oryzae $7&& 7KLV UHVHDUFK FRPELQHV WKH LQKHUHQW DQWLPLFURELDO DFWLYLW\ RI VLOYHU PHWDOV ZLWK WKH Taxus baccata H[WUDFW \LHOGLQJ DQWLEDFWHULDO DFWLYLW\ HQKDQFHG $J13V Keyword: 6LOYHU QDQRSDUWLFOHV 1DQRWHFKQRORJ\ Taxus baccata H[WUDFW $QWL EDFWHULDO $QWL IXQJDO 6\QHUJLVWLF HIIHFWV

1. INTRODUCTION Fundamental and applied physico-chemical research in WKH ¿HOG RI QDQR PDWHULDOV KDV ZLWQHVVHG UDWKHU JUHDW boom in the last few years. Nano materials attract attention due to their unique physico-chemical properties that are rooted in their diameter, eventually in their large surface area. These unique properties cannot be additionally found for the chemically identical material LQ LWV EXON IRUP 7KH QDQRSDUWLFOHV 13V DUH QRW QRZD(*) Corresponding Author - e-mail: l.delshad63@gmail.com

GD\V RQO\ WKH WDUJHW RI VFLHQWL¿F UHVHDUFK EXW WKH\ FDQ be continuously more and more frequently found not RQO\ LQ VFLHQWL¿F ODERUDWRULHV LQGXVWULDO DSSOLFDWLRQV and chemical technologies but also as a part of common life due to their usage in commercially available products [1, 2]. Silver ions and silver-based compounds are highly toxic to microorganisms. Thus, silver ions have been used in many kinds of formulations [3], and

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30

recently it was shown that hybrids of silver nanoparticles with amphiphilic hyperbranched macromolecules H[KLELW HIIHFWLYH DQWLPLFURELDO VXUIDFH FRDWLQJ > @ 6LOYHU 13V FDQ HIIHFWLYHO\ HOLPLQDWH EDFWHULD DQG \HDVWV HYHQ DW UDWKHU ORZ FRQFHQWUDWLRQV LQ XQLWV RI PJ / > 6]. These low concentrations are not additionally toxic DJDLQVW KLJKHU RUJDQLVPV > @ 7KH VLOYHU 13V FDQ be, due to its high antibacterial activity, low toxicity against higher organisms and unproved bacterial resistance, considered one of the greatest antibacterial agents for the treatment of burns [8] or for the prevention of bacterial colonization on catheters, prosthetics DQG GHQWDO PDWHULDOV > @ Antibiotics are one of our most important weapons LQ ÂżJKWLQJ EDFWHULDO LQIHFWLRQV DQG KDYH JUHDWO\ EHQHÂżWHG WKH KHDOWK UHODWHG TXDOLW\ RI KXPDQ OLIH VLQFH their introduction. However, over the past few deFDGHV WKHVH KHDOWK EHQHÂżWV DUH XQGHU WKUHDW DV PDQ\ commonly used antibiotics have become less and less effective against certain illnesses not only because many of them produce toxic reactions but also due to emergence of drug resistant bacteria. It is essential to investigate newer drugs with lesser resistance. Systematic studies among various pharmacological compounds have revealed that any drug may have the possibility of possessing diverse functions and thus may have useful activity in completely different spheres of medicine. Drugs derived from natural sources play D VLJQLÂżFDQW UROH LQ WKH SUHYHQWLRQ DQG WUHDWPHQW RI human diseases. In many developing countries, traditional medicine is one of the primary health care systems [16, 17]. Herbs are widely exploited in the traditional medicine and their curative potentials are well documented [18]. Taxus baccata or the European yew is distributed throughout the temperate zones of the northern hemisphere. It is a small to mediumsized evergreen tree that historically has been used for weapon-making and medicine, and is poisonous except for the fruit [19]. The genus Taxus belongs to WKH &ODVV 3LQRSVLGD WKH 2UGHU 7D[DOHV DQG WKH )DPLO\ Taxaceae. As the species are highly similar, they are often easier to separate geographically than morphoORJLFDOO\ 7\SLFDOO\ HLJKW VSHFLHV DUH UHFRJQL]HG > @ The genus Taxus has generated considerable interest due to its content of diterpene alkaloids, particularly taxol (known also as the generic drug paclitaxel and 26

Delshad L et al

by the registered trade name TaxolÂŽ BMS [BristolMyers Squibb]). The anticancer properties of taxol were discovered in T. brevifolia extracts in 1971 [21].

This plant is used traditionally for the treatment of KLJK IHYHU DQG SDLQIXO LQĂ&#x20AC;DPPDWRU\ FRQGLWLRQV 7KH leaves of this plant are used to make herbal tea for LQGLJHVWLRQ DQG HSLOHSV\ 3UHYLRXVO\ SXEOLVKHG OLWHUDtures on T. wallichiana have reported immunomodulatory, anti-bacterial, anti-fungal, analgesic, anti-pyretic and anti-convulsant activities [22, 23].

2. MATERIALS AND METHODS 2.1. Plant material Fresh leaves of the forests of northern Iran were collected. Then plant was washed thoroughly with tap water followed with sterilized distilled water for the UHPRYDO RI GXVW DQG VDQG SDUWLFOHV 7KH Ă&#x20AC;RZHUV ZHUH shade dried in the dark at room temperature for few GD\V DQG WKHQ KRPRJHQL]HG WR ÂżQH SRZGHU E\ D PHFKDQLFDO JULQGHU WKH SRZGHUHG PDWHULDOV ZHUH SDVVHG WKURXJK VLHYH QXPEHU DQG VWRUHG 2.2. Preparation of plant extracts 3ODQW H[WUDFWV ZHUH SUHSDUHG DFFRUGLQJ WR D VWDQGDUG SURWRFRO 3UHSDUHG SODQW PDWHULDO J ZDV WUDQVIHUUHG WR GDUN FRORXUHG Ă&#x20AC;DVNV DQG PL[HG ZLWK GLIIHUHQW VROYHQW ZDWHU DQG HWKDQRO HWKDQRO DQG distilled water) respectively and stored at room temSHUDWXUH DQG LQ WKH GDUN $IWHU K LQIXVLRQV ZHUH ÂżOWHUHG WKURXJK :KDWPDQ 1R ÂżOWHU SDSHU DQG UHVLdue was re-extracted with equal volume of solvents. $IWHU K WKH SURFHVV ZDV UHSHDWHG &RPELQHG VXpernatants were evaporated to dryness under vacuum DW Â&#x192;& DQG ZLWK USP XVLQJ 5RWDU\ 1 6 +6 South Korea) evaporator. The obtained extracts were kept in sterile sample tubes and stored in a refrigeraWRU DW Â&#x192;& $IWHU HYDSRUDWLRQ RI WKH VROYHQW WKH FUXGH extract was subjected to subsequent analysis. Silver QDQRSDUWLFOHV ZHUH V\QWKHVL]HG LQ WKH /DERUDWRU\ RI 3K\VLFV 8QLYHUVLW\ <DVRXM DQG VL]H RI QDQRSDUWLFOHV ZDV FRQÂżUPHG E\ 6(0 DQG ;5' PHDVXUHPHQWV 2.3. Antibacterial activity (in vitro) 7KH &RPSRXQGV H[WUDFW $J13V PL[WXUH RI H[WUDFW

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30

Table 1: Antibacterial activities of constructed disks soaked in 80, 40 and 20 mg/mL of compounds (extract, AgNPs, mixture of extract with AgNPs) in diameter zone (mm) on various bacterial strains.

*UDP QHJDWLYH EDFWHULD PJ P/ Compounds

Escherichia coli

Klebsiella pneumoniae

Acinetobacter baumannii

Gram positive EDFWHULD PJ P/ Staphylococcus aureus

Extract

11.73

9.33

9.72

8.63

$J13V

13.72

11.23

16.12

Mixture

12.62

11.83

16.82

ZLWK $J13V ZHUH DSSUDLVHG IRU WKHLU DQWLEDFWHULDO activities by disk diffusion method at Muller Hinton agar medium (Merck, Germany) against three Gramnegative bacteria such as E. coli (ATCC33218), and Acinetobacter baumannii $7&& Klebsiella pneumoniae (ATCC1827) and also Gram-positive bacteria including S. aureus $7&& > @ )RU WKLV PHDQ P/ RI WKH DJDU PHGLXP ZDV SRXUHG LQWR D VHULHV RI VWHULOH SHWUL SODWHV 7KHQ P/ RI WKH VSHFLÂżF EDFWHULXP LQFOXGLQJ QHDUO\ 6 colonyIRUPLQJ XQLWV &)8 P/ HTXDO WR 0F)DUODQG VWDQGDUGV ZDV LQRFXODWHG IRU K ROG RQ WKH VXUIDFH of the plates and then swabbed and kept for adsorpWLRQ DERXW PLQ > @ 6WHULOH SDSHU GLVNV PP LQ diameter) were loaded with trial samples which had EHHQ SUHSDUHG RQ GLIIHUHQW FRQFHQWUDWLRQV PJ P/ LQ '062 SODFHG RQ WKH DJDU PHGLXP $OO WKH SODWHV ZHUH LQFXEDWHG DW Â&#x192;& IRU K $QWLEDFWHrial activities of compounds were evaluated based on diameter of zone of inhibition (mm) and tabulated in 7DEOH $FFRUGLQJ WR SUHYLRXV UHSRUWV > @ WKHUH LV QR QRWDEOH HIIHFW IRU '062 RQ WKH ELRORJLFDO HQYLronment. Gentamicin and for Gram-positive bacteria, Cephalexin were used as reference bactericidal drugs (positive controls).

0LQLPXP LQKLELWRU\ FRQFHQWUDWLRQ 0,&

The lowest concentration that prevents the growth of bacteria is considered as MIC. The MIC of the FRPSRXQGV ZDV DVVHVVHG DJDLQVW D VSHFLÂżHG EDFWHrium based on a broth dilution method (Table 2). In this method, various concentrations of compounds Âą PJ P/ ZHUH SUHSDUHG LQ WKH VWHULOH WHVW WXEHV XVLQJ WKH VHULDO GLOXWLRQ PHWKRG 7KHQ P/

9.22

12.33 13.32

RI VWHULOH 0XOOHU +LQWRQ EURWK PHGLXP DQG P/ RI EDFWHULXP ZHUH DGGHG WR WHVW WXEHV DQG LQ ÂżQDO WKH VHWV ZHUH LQFXEDWHG DW Â&#x192;& IRU K 0HDVXUHG PLQLPXP EDFWHULFLGDO FRQFHQWUDWLRQ 0%&

0%& RI &RPSRXQGV H[WUDFW $J13V PL[WXUH RI H[WUDFW ZLWK $J13V ZHUH LQYHVWLJDWHG E\ VXE FXOWXUing a loop full of broth dilution MIC tests to Muller Hinton Agar medium on a plate and then incubated at Â&#x192;& IRU K > @ ,Q WKLV PHWKRG FRXOG REVHUYH EDFterial growth on the surface of agar medium (Table 2).

2.6. Antifungal effects $QWLIXQJDO DFWLYLWLHV RI &RPSRXQGV H[WUDFW $J13V PL[WXUH RI H[WUDFW ZLWK $J13V ZHUH FKHFNHG DJDLQVW two fungal strains such as A. oryzae. For activity measurement, the prepared discs (that had been soaked in WKH YDULRXV FRQFHQWUDWLRQ RI FRPSRXQGV PJ P/ LQ '062 ZHUH SODFHG DW GLIIHUHQW SRVLWLRQV on a surface of petri plates covered by Sabouraud dexWURVH DJDU 6'$ PHGLXP 2[RLG +DPSVKLUH (QJODQG ZKLFK KDYH EHHQ IHFXQGDWHG ZLWK P/ &)8 P/ RI IXQJDO VSRUH VXVSHQVLRQV 7KH SODWHV ZHUH LQFXEDWHG DW Â&#x192;& IRU GD\V IRU A. oryzae (Table

> @ $ FRPPHUFLDO DQWLELRWLF WR FRQWURO WKH $Pphotericin B was chosen.

3. RESULTS AND DISCUSSION 3.1. Antibacterial bioassay (in vitro) The antimicrobial activity of Compounds (extract, $J13V PL[WXUH RI H[WUDFW ZLWK $J13V ZHUH VWXG27

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30

D

Delshad L et al

E

F

Figure 1: Zone of the inhibition of the growth of constructed disks (soaked in 80, 40 and 20 mg/mL) of compounds against four bacteria.

LHG LQ GLIIHUHQW FRQFHQWUDWLRQV PJ P/

against four pathogenic bacterial strains Gram positive S. aureus $7&& WKUHH *UDP QHJDtive E. coli (ATCC33218), Acinetobacter baumannii $7&& Klebsiella pneumoniae (ATCC1827).

The results of the antibacterial activities are presented in Table 1 and Figure 1. The acquired results revealed WKDW WKH HIÂżFLHQF\ RI WKHVH FRPSRXQGV DV FRPSDUHG WR

standard antibiotics (Gentamicin and Cephalexin) in our conditions the antibacterial activity of the ComSRXQGV H[WUDFW $J13V PL[WXUH RI H[WUDFW ZLWK $J13V LQFUHDVHG OLQHDUO\ ZLWK LQFUHDVH LQ FRQFHQWUDWLRQ RI &RPSRXQGV PJ P/ 7KH H[WUDFW H[KLELWV WKH KLJKHVW DFWLYLW\ DW WKH ORZHVW FRQFHQWUDWLRQ RI PJ P/ VKRZHG ZKLFK LV HTXDO WR PP DJDLQVW E. coli, while extract had lowest effect against S. aureus. For

Table 2: Antibacterial activity (MBC and MIC in mg/mL) Taxus baccata L. extract and silver nanoparticles and their combination microdilution method.

Extract and synthesized silver nanoparticles

28

Bio Silver nanoparticles

extract Taxus baccata Bacteria

MIC

MBC

MIC

MBC

MIC

MBC

S. aureus E.coli

Acinetobacter baumannii

Klebsiella pneumoniae

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30

Table 3: Antifungal activities of constructed disks (soaked in 80, 40 and 20 mg/mL of compounds (extract, extract with AgNP, AgNP) based on diameter zone (mm) against fungal Aspergillus oryzae.

Compounds

Aspergillus oryzae PJ P/

Extract $J13

6.23

8.12 9.87

Mixture

9.21

$J13V H[KLELWV WKH KLJKHVW DFWLYLW\ LQ WKLV FRQFHQWUDtion showed which is equal to 13.22 mm against Klebsiella pneumoniae and for the bacterial extract when mixed with silver nanoparticle inhibition zone diameWHU PP UHVSHFWLYHO\ 7KHVH UHVXOWV GHPRQVWUDWH that the synergistic combination of the antibacterial DFWLYLW\ RI WKH H[WUDFW ZLWK $J13V HQKDQFHV WKH DQtimicrobial effects. As it was noted above, the determination of the bactericidal effect of the Compounds H[WUDFW $J13V PL[WXUH RI H[WUDFW ZLWK $J13V WR the reference strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii was achieved by means of the dilution method MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration). MIC of Taxus baccata L. H[WUDFWV ZDV WKH OHDVW PJ P/

for inhibition of growth of Acinetobacter baumannii, 0,& DQG 0%& IRU $J13V PJ P/ DJDLQVW Escherichia coli. MIC and MBC mix Taxus baccata L. exWUDFW ZLWK $J13V ZDV PJ P/ DJDLQVW Staphylo-

coccus aureus. In the case of Acinetobacter baumannii EDFWHULXP WKH ORZHVW 0%& ZDV REWDLQHG PJ P/ belonged to Taxus baccata L. activity of the medicinal SODQW ZLWK $J13V HQKDQFHV WKH DQWLPLFURELDO HIIHFWV 3.2. Antifungal bioassay (in vitro) In addition to antibacterial activities, compounds (exWUDFW $J13V PL[WXUH RI H[WUDFW ZLWK $J13V ZHUH subjected to antifungal activities against A. oryzae fungal strain and the zone diameters of inhibition (mm) have been summarized in Table 3. Also for a clear comparison, the zone of the inhibition of the JURZWK IRU GLVNV FRQVWUXFWHG E\ VRDNLQJ LQ PJ P/ RI FRPSRXQGV H[WUDFW $J13V PL[WXUH RI H[WUDFW ZLWK $J13V LQ '062 KDV EHHQ GHSLFWHG DV FROXPQ FKDUW LQ )LJXUH LQYHVWLJDWLRQV UHYHDOHG WKDW $J13V has excellent antifungal activity on used funguses with respect to extract and mixture extract with Ag13V )LQDOO\ LW LV WR EH QRWHG WKDW WKH UHVXOWV LQ DQWLPLFURELDO ELRDVVD\ LQGLFDWH WKDW WKH PL[WXUH RI $J13V WR H[WUDFW LPSURYHV VLJQLÂżFDQWO\ LWV DQWLEDFWHULDO DQG antifungal activity.

4. CONCLUSIONS

Figure 2: Zone of the inhibition of the growth of constructed disks (soaked in 80 mg/mL) of compounds against fungal Aspergillus oryzae.

%DVHG RQ WKHVH ÂżQGLQJV WKH VLOYHU 13V GR QRW UHSUHsent any risk for human beings, when used in medical applications and commercially available products, but only under the condition that the silver concentration LV UHWDLQHG DW XQLWV RI PJ / ZKLFK LV VXIÂżFLHQW IRU WKH suppression of bacterial and yeast growth. Antimicrobial properties of medicinal plants are being increasingly reported from different parts of the world. The world health organization estimates that plant extract or their active constituents are used as folk medicine 29

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30

LQ WUDGLWLRQDO WKHUDSLHV RI RI WKH ZRUGV SRSXODtion. In the present work, extracts obtained from Taxus baccata L. shows strong activity against most of the tested bacteria and fungal strains. The results were compared with standard antibiotic drugs. From the above results the activities of hydroalcohol extracts of Taxus baccata L. VKRZV VLJQL¿FDQW DQWLEDFWHULDO DQG antifungal activity. The results showed that the Taxus baccata L. extract against bacteria and fungus inhibiting effect was tested. Applications of Ag nanoparticles EDVHG RQ WKHVH ¿QGLQJV PD\ OHDG WR YDOXDEOH GLVFRYHULHV LQ YDULRXV ¿HOGV VXFK DV PHGLFDO GHYLFHV DQG DQWLmicrobial systems.

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9. Gosheger G., Hardes J., Ahrens H., Streitburger A., Buerger H., Erren M., Gunsel A., Kemper

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ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Synthesis of Nano-Sized Titania Particles by Hydrolysis of Titanium Tetrachloride Majid Farahmandjou1*, Mahbobeh Ramazani2 1

Associate Professor, Department of Physics, Varamin-Pishva Branch, Islamis Azad University, Varamin, Iran 2

M.Sc., Department of Physics, Varamin Pishva Branch, Islamis Azad University, Varamin, Iran

5HFHLYHG 1RYHPEHU $FFHSWHG -DQXDU\

ABSTRACT 1DQR VL]HG WLWDQLXP GLR[LGH 7L2 SRZGHU ZDV VXFFHVVIXOO\ SUHSDUHG IURP LWV SUHFXUVRU WLWDQLXP ,9 FKORULGH E\ D VLPSOH DQG QHZ ZHW FKHPLFDO PHWKRG 7L&O ZHUH XVHG DV SUHFXUVRU LQ K\GURJHQ SHUR[LGH + 2 DQG HWKDQRO 7KLV VROXWLRQ ZDV WKHQ SHSWL]HG XVLQJ QLWULF DFLG DQG KHDWHG XQGHU UHĂ&#x20AC;X[ DW Â&#x192;& 7KHLU SK\VLFR FKHPLFDO SURSHUWLHV ZHUH WKHQ FKDUDFWHUL]HG E\ WUDQVPLVVLRQ HOHFWURQ PLFURVFRS\ 7(0 VFDQQLQJ HOHFWURQ PLFURVFRS\ 6(0 DQG ; 5D\ GLIIUDFWLRQ ;5' 7KH 7(0 UHVXOWV VKRZHG WKDW WKH VL]H RI DV V\QWKHVL]HG 7L2 QDQRSDUWLFOHV ZHUH LQ WKH UDQJH RI QP 7KH 6(0 LPDJHV VKRZHG WKDW WKH VL]H RI QDQRSDUWLFOHV LQFUHDVHG ZKHQ WKH QDQRSDUWLFOHV SUHSDUHG LQ SUHVHQFH RI QLWULF DFLG 7KH 6(0 LPDJHV VKRZHG WKDW WKH TXDOLW\ RI DQQHDOHG 7L2 QDQRDSUWLFOHV LQFUHDVHG ZKHQ WKH QDQRSDUWLFOHV V\QWKHVL]HG ZLWKRXW QLWULF DFLG 7KH FU\VWDO VWUXFWXUH RI WKH QDQRSDUWLFOHV EHIRUH DQG DIWHU DQQHDOLQJ ZDV GRQH E\ ;5' DQDO\VLV ,W ZDV UHDOL]HG WKDW WKH UXWLOH SKDVH ZDV IRUPHG DIWHU KHDW WUHDWPHQW DW Â&#x192;& ;5' SDWWHUQ DOVR VKRZHG WKDW WKH VL]H RI DQQHDOHG 7L2 QDQRSDUWLFOHV LQFUHDVHG IURP WR QP ZKHQ WKH QDQRSDUWLFOHV SUHSDUHG ZLWK QLWULF DFLG Keyword: 7LWDQLXP GLR[LGH 1DQRSDUWLFOHV &KHPLFDO V\QWKHVLV &U\VWDO VWUXFWXUH 5XWLOH SKDVH $QDWDVH SKDVH &KDUDFWHUL]DWLRQ

1. INTRODUCTION 1DQRFU\VWDOOLQH VHPLFRQGXFWRU 7L22 particles are of interest due to their unique properties and several potential technological applications such as photocatalyVLV VHQVRUV VRODU FHOOV DQG PHPRU\ GHYLFHV > @ 7L22 exists in three polymorphic phases: rutile (tetragonal GHQVLW\ J FP3 DQDWDVH WHWUDJRQDO J FP3) DQG EURRNLWH RUWKRUKRPELF J FP3). Both anatase and rutile have tetragonal crystal structures but belong

(*) Corresponding Author - e-mail: farahmandjou@iauvaramin.ac.ir

to different space groups. Anatase has the space group , 1/amd with four formula units in one unit cell and ruWLOH KDV WKH VSDFH JURXS 3 2 PQP ZLWK WZR 7L22 formuOD XQLWV LQ RQH XQLW FHOO > @ 7KH ORZ GHQVLW\ VROLG phases are less stable and undergo transition rutile in the solid state. Among the three above mentioned crysWDO VWUXFWXUHV RI 7L22, anatase owing to its higher photocatalytic activity is commonly used for photocataly-

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 31-34

sis [11]. This higher photocatalytic activity is related to its lattice structure. Each Ti atom is coordinated to six oxygen atoms in anatase tetragonal unit cell. The RFWDKHGURQ LQ DQDWDVH LV VLJQLÂżFDQWO\ GLVWRUWHG VR WKDW its symmetry is lower than orthorhombic. The Ti-Ti GLVWDQFH LQ DQDWDVH LV JUHDWHU ZKHUHDV WKH 7L 2 GLVtances are shorter than in rutile. In the rutile structures HDFK RFWDKHGURQ LV LQ FRQWDFW ZLWK QHLJKERU RFWDKHdrons, while in the anatase structure each octahedron is in contact with eight neighbors. These differences in lattice structures cause different mass densities and electronic band structures between the two forms of 7L22. The low-density solid phases are less stable and undergo transition rutile in the solid state. The transformation is accelerated by heat treatment and occurs DW WHPSHUDWXUHV EHWZHHQ DQG Â&#x192;& > @ 7KLV transformation is dependent on several parameters such as initial particle size, initial phase, dopant concentration, reaction atmosphere and annealing temSHUDWXUH HWF > @ 7L22 nanoparticles can be synthesized using variRXV PHWKRGV VXFK DV VXOIDWH SURFHVV > @ FKORULGH SURFHVV > @ LPSUHJQDWLRQ > @ FR SUHFLSLWDWLRQ > @ hydrothermal method [18, 19], direct oxidation of TiCl > @ PHWDO RUJDQLF FKHPLFDO YDSRU GHSRVLWLRQ method, etc. [1, 21]. Wet chemical method has novel features which are of considerable interest due to its low cost, easy preparation and industrial viability.

Anatase phase are commonly obtained by hydrolysis of titanium compounds, such as titanium tetrachloride (TiCl ) [22]. In this study, we report the synthesis of 7L22 nanoparticles system by wet chemical route. AnDWDVH DQG UXWLOH SKDVHV RI 7L22 are obtained by TiCl precursor. The morphology of the nanoparticles has EHHQ FKDUDFWHUL]HG E\ ;5' 7(0 DQG 6(0 DQDO\VHV

2. EXPERIMENTAL DETAIL The titania nanoparticles were synthesized by drop wise addition of titanium tetrachloride: TiCl P/ LQ HWKDQRO VROXWLRQ P/ 7KH UHDFWLRQ ZDV SHUIRUPHG at room temperature while stirring under a fume hood due to the large amount of Cl2 and HCl gases evolved in this reaction. The resulting yellow solution was allowed to rest and cool back to room temperature as the 32

Farahmandjou M & Ramazani M

gas evolution ceased. The suspensions obtained were GULHG LQ DQ RYHQ IRU VHYHUDO KRXUV DW Â&#x192;& XQWLO DPRUSKRXV DQG GULHG 7L22 particles were obtained. After WKDW P/ K\GURJHQ SHUR[LGH +222 was added to the solution. The light yellow colored solution changed to red colored. The total volume of the solution was DGMXVWHG WR P/ E\ DGGLQJ HWKDQRO VROXWLRQ 7KLV VROXWLRQ ZDV WKHQ SHSWL]HG XVLQJ QLWULF DFLG P/

DQG KHDWHG XQGHU UHĂ&#x20AC;X[ DW Â&#x192;& IRU KRXU LQ D FORVHG vessel. The obtained powder samples were calcined IRU KRXUV LQ D ER[ IXUQDFH DW WHPSHUDWXUH Â&#x192;& LQ an ambient atmosphere. The morphology of the asV\QWKHVLV DQG DQQHDOHG 7L22 nanoparticles were done. ; 5D\ GLIIUDFWRPHWHU ;5' ZDV XVHG WR LGHQWLI\ WKH crystalline phase and to estimate the crystalline size.

7KH ;5' SDWWHUQ ZHUH UHFRUGHG ZLWK Č&#x2122; LQ WKH UDQJH RI Â&#x192; ZLWK W\SH ; 3HUW 3UR 03' &X .ÄŽ Č&#x153; c 7KH PRUSKRORJ\ ZDV FKDUDFWHUL]HG E\ ÂżHOG HPLVsion scanning electron microscopy (SEM) with type .<.< (0 N9 DQG WUDQVPLVVLRQ HOHFWURQ PLFURVFRS\ 7(0 ZLWK W\SH =HLVV (0 N9

3. RESULTS AND DISCUSSION ; 5D\ GLIIUDFWLRQ ;5' DW .Y ZDV XVHG WR LGHQWLI\ crystalline phases and to estimate the crystalline sizHV )LJXUH D VKRZV WKH ;5' PRUSKRORJ\ RI 7L22 nanoparticles and indicates the structure of tetragonal DQDWDVH SKDVH 7KH ;5' SDWWHUQV VKRZHG WKLV VDPSOH KDYH IRXU VKDUS SHDNV Č&#x2122; DQJOH DW WKH SHDN SRVLWLRQ DW Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; DQG Â&#x192; ZLWK

DQG

diffraction planes, respectively are in accordance with WKH 7L22 anatase phase. It can be seen the peak posiWLRQ DW R FRUUHVSRQGV WR WKH SODQH RI UXWLOH IRUP 7KH PHDQ VL]H RI WKH RUGHUHG 7L22 nanoparticles has been estimated from full width at half maximum (FWHM) and Debye-Sherrer formula according to equation the following: D

O Bcos T

(1)

ZKHUH LV WKH VKDSH IDFWRU Č&#x153; LV WKH ; 5D\ ZDYHlength, B is the line broadening at half the maximum LQWHQVLW\ ):+0 LQ UDGLDQV DQG Č&#x2122; LV WKH %UDJJ DQ-

Farahmandjou M & Ramazani M

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 31-34

Figure 1: XRD pattern of TiO2 nanoparticles (a) as-prepared (red line) (b) annealed at 600°C without nitric acid (blue line) (c) annealed at 600°C with nitric acid (green line).

JOH 7KH PHDQ VL]H RI DV SUHSDUHG 7L22 nanoparticles was 7 nm from this Debye-Sherrer equation.

The crystal structure of the nanoparticles before (red OLQH DQG DIWHU EOXH OLQH DQQHDOLQJ ZDV GRQH E\ ;5' analysis. It is realized that in the rutile phase the size RI DQQHDOHG 7L22 QDQRSDUWLFOHV LQFUHDVH IURP WR nm when the nanoparticles prepared with nitric acid (green line).

Scanning electron microscope (SEM) was used for

WKH PRUSKRORJLFDO VWXG\ RI QDQRSDUWLFOHV RI 7L22.

These Figures show that high homogeneity emerged in the samples surface by increasing annealing temperature. The results show that with increasing annealing temperature the morphology of the particles changes to the spherical shape and nanopowders are less agglomerated. Figure 2(a) shows the SEM images RI WKH DV SUHSDUHG 7L22 nanoparticles with spherelike shaped prepared by wet chemical method. FigXUH E VKRZV WKH 6(0 LPDJHV RI WKH DQQHDOHG 7L22 nanoparticles prepared in presence of nitric acid at & IRU KRXUV )LJXUH F VKRZV WKH DQQHDOHG 7L22 nanoparticles prepared in absence of nitric acid. ,W FDQ EH VHHQ WKDW WKH 7L22 nanoparticles are not agglomerated. In this Figure, the spherical shaped particles with clumped distributions are visible through the SEM analysis. The average crystallite size of annealed QDQRFU\VWDOV LQFUHDVHG IURP QP ZKHQ WKH SDUticles synthesized in presence of nitric acid.

The transmission electron microscopic (TEM) anal\VLV ZDV FDUULHG RXW WR FRQ¿UP WKH JURZWK SDWWHUQ RI the particles. Figure 3 shows the as-synthesized TEM image of titanium dioxide prepared by wet synthesis.

(b)

(a)

(c)

Figure 2: SEM images of the TiO2 nanoparticles (a) as-prepared (b) annealed at 600°C in presence of nitric acid (c) annealed at 600°C in absence of nitric acid.

33

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 31-34

Figure 3: TEM images of the as-prepared TiO2 nanoparticles.

7KH VL]H RI DV SUHSDUHG DQDWDVH 7L22 nanoparticles is about 7 nm in diameter.

4. CONCLUSIONS ,Q VXPPDU\ DQDWDVH DQG UXWLOH 7L22 nanoparticles were successfully synthesized via a simple and new wet FKHPLFDO V\QWKHVLV URXWH $QDWDVH 7L22 was obtained from wet synthesis method. TEM results showed that WKH VL]H RI DV V\QWKHVL]HG 7L22 nanoparticles was deWHUPLQHG LQ WKH UDQJH RI QP 6(0 LPDJHV VKRZHG WKDW WKH VL]H RI DQQHDOHG 7L22 nanoparticles increased IURP QP ZKHQ WKH QDQRSDUWLFOHV SUHSDUHG ZLWK QLWULF DFLG ;5' SDWWHUQ RI 7L22 nanoparticles indicated the structure of rutile phase with annealing process DW Â&#x192;& ;5' SDWWHUQ DOVR FRQÂżUPHG WKH LQFUHDVLQJ VL]H RI 7L22 nanoparticles in presence of nitric acid.

ACKNOWLEDGMENT 7KH DXWKRUV DUH WKDQNIXO IRU WKH ÂżQDQFLDO VXSSRUW RI varamin pishva branch at Islamic Azad University for analysis and the discussion on the results.

REFERENCES /L : ,VPDW 6KDK 6 +XDQJ & 3 -XQJ 2 1L & Mater. Sci. Eng. B, 96

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5HLG\ ' - +ROPHV - ' 0RUULV 0 $ J. Eur. Ceram. Soc., 26

5DKLP 6 5DGLPDQ 6 DQG +DP]DK $ Sains Malaysiana, 41

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/HH & + 5KHH 6 : &KRL + : Nanoscale Res. Lett., 7

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$QZDU 1 6 .DVVLP $ /LP + / =DNDU\D 6 $ Huang N.M., Sains Malaysiana, 39

:DQJ : 1 /HQJJRUR : 7HUDVKL < .LP 7 2 2NX\DPD . Mater. Sci. Engineering B, 123

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=KDQJ + %DQÂżHOG - ) Am. Mineral., 84 (1999),

/LDQJ < *DQ 6 6FRWW $ Phys. Rev. B, 63

7VHYLV $ 6SDQRV 1 .RXWVRXNRV 3 * J. Chem.

Soc. Faraday Trans, 94

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+RZH 0 *UDQW (G .LUN 2WKPHU Encyclopedia of Chemical Technology, John Wiley & Sons, Inc. /LWWHU 0 , 1DYLR - $ J. Photochem. Photobiol.

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'LQJ = +X ; /X * 4 <XH 3 / *UHHQÂżHOG 3 ) Langmuir, 16

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 35-38

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Preparation and Characterization of ZrO2/ZnO Nanocomposite under Ultrasonic Irradiation via Sol-gel Route Shokufeh Aghabeygi1*, Maryam Zare-Dehnavi2, Ali Farhadyar3, Nazanin Farhadyar4 1

Assistant Professor, Department of Chemistry, East Tehran Branch, Islamic Azad University, Tehran, Iran 2

Instructor, Department of Chemistry, East Tehran Branch, Islamic Azad University, Tehran, Iran 3

4

Ph.D., Agribusiness Department, Armenian State Agrarian University, IRAN

Assistant Professor, Department of Chemistry, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran

5HFHLYHG 1RYHPEHU $FFHSWHG -DQXDU\

ABSTRACT 1DQRFRPSRVLWH RI =U2 =Q2 ZDV SUHSDUHG XQGHU XOWUDVRQLF LUUDGLDWLRQ E\ VRO JHO SURFHVV IURP GLUHFWO\ PL[LQJ =LUFRQLXP DQG =LQF JHOV DQG WKH PL[WXUH ZDV SODFHG XQGHU XOWUDVRQLF LUUDGLDWLRQ IRU KRXUV WKHQ DJLQJ WLPH WKH ÂżOWUDWHG FRPSRVLWH JHO ZDV FDOFLQDWHG DW Â&#x192;& IRU K LQ IXUQDFH 7KH SUHFXUVRU VRO RI ]LUFRQLXP ZDV SUHSDUHG IURP DQ DTXHRXV VROXWLRQ RI =U&O DQG ]LQF DFHWDWH GLK\GUDWHG ZDV GLVVROYHG LQ GH LRQL]HG ZDWHU 7KH )7 ,5 DQDO\VLV DQG WKH ;5' VWXG\ ZHUH H[KLELWHG WKDW WKH FU\VWDO VWUXFWXUH DQG SXULW\ RI WKH =U2 =Q2 QDQRFRPSRVLWH )(6(0 LPDJHV ZDV LQGLFDWHG WKH PRUSKRORJ\ DQG WKH DYHUDJH VL]H RI WKH 13V 7KH DYHUDJH VL]H RI WKH =U2 =Q2 QDQRFRPSRVLWH ZDV GHWHUPLQHG QP Keyword: =LUFRQLD =Q2 1DQRFRPSRVLWH 3DUWLFOH VL]H 6RO JHO 8OWUDVRQLF LUUDGLDWLRQ

1. INTRODUCTION In recent years, there has been increasing interest in WKH DSSOLFDWLRQ RI QDQR VL]H =LUFRQLD DQG =LQF R[LGH for catalysts and supports, ceramics, inorganic memEUDQHV JDV VHQVLQJ ZDWHU SXULÂżFDWLRQ DQG VRODU HQHUJ\ FRQYHUVLRQ > @ =U22 has unique characteristics, such as weak acidity, basicity, redox and high thermal staELOLW\ 6LQFH WKH EHQHÂżFLDO SK\VLFDO FKHPLFDO SURSHUWLHV strongly depend on the particle size, the controlled and reliable preparation of nano-ranged materials represents D SDUWLFXODU FKDOOHQJH EHLQJ UHĂ&#x20AC;HFWHG E\ QXPHURXV DS(*) Corresponding Author - e-mail: saghabeygi@yahoo.com

SURDFKHV IRU LQVWDQFH Ă&#x20AC;DPH V\QWKHVLV > @ FKHPLFDO YDSRU GHSRVLWLRQ > @ 6RO JHO SURFHVVHV > @ K\GURWKHUPDO synthesis [6], sonocation [7] and polyol synthesis [8].

'XH WR LWV XQLTXH SURSHUWLHV =U22 is widely used for gas VHQVRUV FHUDPLFV VRUEHQWV DQG FDWDO\VWV FRQFHUQLQJ WKH ODWWHU =U22 is particularly employed as catalyst carULHU LQ WKH VHOHFWLYH FDWDO\WLF UHGXFWLRQ RI 12[ E\ 1+3 6&5 > @ ,Q PRVW FDVHV WKH SUHFXUVRUV DUH VROXEOH ]LUFRQLXP VDOWV OLNH =U2 123)2.xH22 =U 123) =U2Cl2.xH22 DQG =U&O > @ ZKHUHDV RUJDQLF ]LUFRQL-

Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 1 (2015), 35-38

um compounds have been used as well [16,17].

Moreover, the sol-gel method allows for the homogeneous mixing of transition-metal cations at a molecular level, which enhances the formation of polycrystalline particles with special properties [18]. The FU\VWDOOLQH SKDVH RI =U22 VWURQJO\ LQĂ&#x20AC;XHQFHV LWV FDWDO\WLF DFWLYLW\ DQG VHOHFWLYLW\ > @ 0RUH DWWHQWLRQ KDV EHHQ SDLG WR =Q2 QDQRVWUXFWXUHV EHFDXVH =Q2 LV DQ LPSRUWDQW ORZ FRVW EDVLF ,,Âą9, wide band gap semiconductor material which is used considerably for its catalytic, electrical, photoelectriFDO DQG SKRWRGHJUDGDWLRQ SURSHUWLHV > @ 5HFHQWO\ using of ultrasonic irradiation has been employed of synthesis and sono-catalyst properties of many nano materials [21, 22].

We have been synthesized the binary nanocomposLWH RI =U22 =Q2 E\ XVLQJ XOWUDVRQLF LUUDGLDWLRQ WKH XOtrasonic probe is very effective in preparation process.

2. EXPERIMENTAL

Aghabeygi S et al

DFKLHYH D =Q2 KRPRJHQRXV JHO 3UHSDUDWLRQ RI =LUFRQLXP JHO )LUVWO\ =U&O J P/ ZDV GLVVROYHG LQ SURSDQRO P/ WR JHW D SUHFXUVRU VROXWLRQ $ VROXWLRQ of H222 P/ Y Y ZDV WKHQ GURSSHG LQWR WKH precursor solution under stirring. The pH of mixture was adjusted 9 by adding ammonium solution 2M XQWLO =LUFRQLXP JHO =U 2+ ) was prepared and the produced gel was aged and stirring for 2 days, Then WKH SUREH RI XOWUDVRQLF ZDV LQWURGXFHG LQ =U22 gel and LW ZDV LUUDGLDWHG IRU PLQ 3UHSDUDWLRQ RI =U22 =Q2 QDQRFRPSRVLWH 7KH =LUFRQLXP DQG =LQF JHOV ZHUH PL[HG WRJHWKHU then the mixture gels were irradiated by the probe of ultrasonic instrument for 2 h. The mixture was stirred IRU K WKHQ LW ZDV ÂżOWUDWHG DQG ZDVKHG VHYHUDO WLPHV After drying at room temperature, the white precipiWDWHG ZDV FDOFLQDWHG DW Â&#x17E;& IRU K LQ IXUQDFH =Q &+ &22 1+ 2+ o =Q 2+ 1+ &+ &22

3UHSDUDWLRQ RI =LQF JHO J PRO =Q &+3&22 2.2H22 ZDV ÂżUVWO\ GLVVROYHG LQ ', ZDWHU P/ DQG VWLUUHG WR JHW D SUHFXUVRU VROXWLRQ P/ 0 1+ 2+ VROXWLRQ ZDV then dropped into the precursor solution until pH of mixture was adjusted 9 and the white suspension of =Q 2+ 2 was appeared. After that, the mixture was continuously stirred for 2 days then the tip of ultrasonic probe was introduced into the mixture and it was LUUDGLDWLRQ XQGHU XOWUDVRQLF LUUDGLDWLRQ IRU PLQ WR

' =U&O + 2 o =U 2+ &O

=U 2+ =Q 2+ o =U2 =Q2 + 2

3. RESULTS AND DISCUSSION )(6(0 LPDJH Surface and morphology of the synthesized nanocomposite have been studied and the FESEM images are

Figure 1: FESEM images of ZrO2/ZnOnanocomposite.

36

Aghabeygi S et al

Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 1 (2015), 35-38

VKRZQ LQ )LJXUH 7KH =U22 =Q2 QDQRSDUWLFOHV DUH VHHQ XQLIRUP 7KH VL]H RI SDUWLFOHV LV QP 3.2. XRD diffraction 7KH ;5' SDWWHUQ RI WKH =U22 =Q2 QDQRFRPSRVLWH LV shown in Figure 2. The distinct peaks corresponding to =Q2 DQG =U22 are observed. It is concluded that both the materials exist in perfect crystalline phases and reWDLQ WKHLU SK\VLFDO VWUXFWXUH DQG KHQFH FRQÂżUPHG WR IRUP D =U22 =Q2 QDQRFRPSRVLWH DFFRUGLQJ WR FDUG QR IRU =U22 DQG FDUG QR IRU =Q2 -RLQW &RPPLWWHH RQ 3RZGHU 'LIIUDFWLRQ 6WDQGDUGV -&3'6

7KH =U22 =Q2 QDQRSDUWLFOHV DUH VHHQ SXUH The average particle size Dv of crystallites in the composite was also roughly calculated based upon the ;5' VSHFWUD IRU TXDQWLWDWLYH SXUSRVH XVLQJ WKH 6FKHUrer equation: Dv

KO E cos T

where: Dv is the â&#x20AC;&#x153;volume weightedâ&#x20AC;? crystallite size = ž d (crystallite diameter) K is the â&#x20AC;&#x153;Scherer constantâ&#x20AC;?

DURXQG Č&#x153; LV WKH ZDYHOHQJWK RI WKH ; 5D\V KHUH is O , CuKD c Č&#x2122; LV WKH %UDJJ DQJOH IRU WKH SHDN DW Č&#x2122; Č&#x2022; LV WKH ÂłLQWHJUDO EUHDGWK´ RI WKH SHDN DW Č&#x2122; 7KH Č&#x2022; Ę&#x152; ):+0 IXOO ZLGWK DW KDOI PD[Lmum) for a Gaussian shaped peak. The crystallite size RI =U22 =Q2 QDQRFRPSRVLWH DFFRUGLQJ WR ;5' 3DWtern is estimated to be 37 nm.

Figure 2: XRD patterns of the ZrO2/ZnO nanocomposite powder.

3.3. FT-IR analysis )7 ,5 VSHFWUXP RI WKH =U22 =Q2 QDQRFRPSRVLWH LV shown in Figure 3, in the wave number range from WR FP-1 7KH SHDNV DW DQG FP-1 can be attributed to symmetric and asymmetry stretchLQJ YLEUDWLRQ RI WKH =UÂą2Âą=U ERQG DQG 2Âą=UÂą2 Ă&#x20AC;H[ion, .The peaks at 869 cm-1 were attributed to the viEUDWLRQ PRGH RI =QÂą2Âą=U 7KH SHDNV DW DQG cm-1 FDQ EH DVVLJQHG WR VWUHWFKLQJ YLEUDWLRQ RI WKH =Q 2 =Q ERQG DQG 2 =Q 2 ERQG UHVSHFWLYHO\ 7KH SHDN DW FP-1 resulted from bending vibration of the adsorbed H22 PROHFXOHV ZKLFK ZHUH QRW UHPRYHG completely after Sol-gel synthesis. The wide peak at

Figure 3: FT-IR spectra of the ZrO2/ZnO nanocomposite powder.

37

Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 1 (2015), 35-38

FP-1 KDV EHHQ DVVLJQHG WR WKH 2+ V\PPHWU\ DQG asymmetry stretching vibration of surface hydroxyl group.

4. CONCLUSIONS =U22 =Q2 QDQRFRPSRVLWH KDV EHHQ V\QWKHVL]HG E\ a facile Sol-gel method using ultrasonic irradiation. =Q &+3&22 2.2H22 DQG =U&O have been used as VWDUWLQJ PDWHULDOV 7KH QDQRFRPSRVLWH RI =U22 =Q2 PRODU UDWLR ZDV FDOFLQDWHG DW Â&#x17E;& &RPSDULVRQ RI WKH )7 ,5 VSHFWUD RI =U22 =Q2 QDQRFRPSRVLWH ZLWK WKH SXUH =U22 DQG =Q2 QDQRSDUWLFOHV KDYH EHHQ VKRZHG IRUPDWLRQ RI =U22 =Q2 QDQRFRPSRVLWH &U\VWDO SKDVH DQG SDUWLFOH VL]H RI 13V FDQ EH GHWHFWHG E\ ;5' $FFRUGLQJ WR ;5' 3DWWHUQV WKH FDOFXODWHG YDOXH DV FU\VWDOOLWH VL]H RI =U22 =Q2 QDQRFRPSRVLWH ZDV obtained around 37 nm.

ACKNOWLEDGEMENT The authors thank the research and technology section of Islamic Azad University East Tehran Branch.

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+HUQDQGH] $ 0D\D / 6DQFKH] ( 0 J. Solâ&#x20AC;&#x201C;Gel Sci. Technol., 42

5KRGHV 0 ' %HOO $ 7 J. Catal., 233

198. /L : +XDQJ + /L + =KDQJ : /LX + Langmuir, 24

21. Huang M.H., Mao S., Feick H., Yan H.Q., Wu < < .LQG + :HEHU ( 5XVVR 5 <DQJ 3 ' Science, 292

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ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials A Theoretical Study of H2S and CO2 Interaction with the SingleWalled Nitrogen Doped Carbon Nanotubes Mohsen Oftadeh1, Morteza Rezaeisadat2*, Alimorad Rashidi3 1

Ph.D., Chemistry Department, Payame Noor University, Tehran 19395-4697, I. R. of Iran

2

M.Sc., Chemistry Department, Payame Noor University, Tehran 19395-4697, I. R. of Iran 3

Ph.D., Nanotechnology Group, Research Center of Tehran Oil Technique, Tehran, Iran

5HFHLYHG 'HFHPEHU $FFHSWHG )HEUXDU\

ABSTRACT 7KH SK\VLFDO DGVRUSWLRQ RI K\GURJHQ VXO¿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¿GH DQG FDUERQ GLR[LGH JDVHV $GVRUSWLRQ RI K\GURJHQ VXO¿GH RQ WKH QDQRWXEHV LV PRUH HIIHFWLYH WKDQ FDUERQ GLR[LGH 0RUHRYHU IRU ERWK JDVHV WKH DGVRUSWLRQ SURFHVVHV DUH WKHUPRG\QDPLFDOO\ IDYRUDEOH 7KHVH QDQRWXEHV FDQ EH HFRQRPLFDOO\ XVHG WR VHSDUDWH VRXU JDVHV IURP QDWXUDO JDVHV DQG WR UHFRYHU WKH VXOIXU Keyword: 'HQVLW\ IXQFWLRQDO WKHRU\ (QHUJ\ DGVRUSWLRQ 6LQJOH ZDOO FDUERQ QDQRWXEH GRSHG ZLWK QLWURJHQ +\GURJHQ VXO¿GH &DUERQ GLR[LGH

1. INTRODUCTION Today nanotechnology is a matter of concern for all SHRSOH DURXQG WKH ZRUOG *UHDW DQG XQLTXH VSHFL¿cations of these modern and new structures lead to a VLJQL¿FDQW UHYROXWLRQ LQ WKH LQGXVWULDO ZRUOG > @ 2QH of the most commonly used structures, which is of a great importance in nanotechnology, is carbon nanoWXEHV &17 6LJQL¿FDQW VSHFL¿FDWLRQV RI &17 DUH

(*) Corresponding Author - e-mail: mory_rezaie@yahoo.com

available from different sources [2]. These characteristics include thermal, chemical and structural properWLHV > @ 1DQRWXEH VWUXFWXUHV FDQ EH GLYLGHG LQWR WKUHH main groups namely, zigzag, armchair and chiral strucWXUHV > @ %HFDXVH RI LWV GLIIHUHQW VWUXFWXUHV DQG YDULous applications, CNT is being increasingly applied in GLIIHUHQW LQGXVWULHV DQG VFLHQFHV > @ 2QH WKH PRVW

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important industries which has been paying so much DWWHQWLRQ WR WKH DSSOLFDWLRQV RI &17 DUH RLO UHÂżQHPHQW and process industry. These structures are so noteworthy due to having high values of length to diameter ratios, low density, homologous porosity and relative high structural stability in adsorption and storage of gases [8-11]. Crude natural gas which is generally extracted from gas wells and crude oil wells consist large amounts of methane, ethane, propane, butane and small amounts of heavier hydrocarbons. In addition to the above mentioned compounds, some other impurities such as carbon dioxide and hydrogen sulÂżGH DUH SUHVHQW LQ WKH QDWXUDO JDV > @ $PRQJ WKHVH LPSXULWLHV FDUERQ GLR[LGH DQG K\GURJHQ VXOÂżGH DUH of a great importance. These are named acidic gases because they react with water and result in acidic compounds. Existence of the acidic gases in the gas pipeline will result in the corrosion and erosion of pipelines [13]. H2S is one of the most harmful environmental pollutants. The crude natural gases are named sour gases due to having sulfur compounds specially H26 > @ 7KH DERYH PHQWLRQHG LVVXHV VKRZ WKH VLJQLÂżFDQFH RI VHSDUDWLQJ &22 from H2S. The process LQ ZKLFK &22 and H2S impurities are separated from the crude natural gas is called sweetening of sour gas.

The most common used methods of sweetening are amine and Klaus methods [16].

Common theoretical methods consist of process simulations, and have relatively lower costs in comparison to the experimental methods. Because nitrogenized compounds have a long history in the adsorption and sweetening of sour gases, the present study sought to analyze and study different structures of single wall nitrogen doped carbon nanotubes (NCNT) in terms of stability, synthesis feasibility and their abundances [17-21]. Having selected the proper structure, the interactions between H26 DQG &22 gases adjacent to NCNT and the pathway of adsorption on the nanotubes were studied. Finally a comparison was done between the adsorption of acidic gases on NCNT and CNT [22].

2. COMPUTATIONAL METHOD Due to the large number of constituent atoms, quan

Rezaeisadat M et al

tum calculations in nanotube structures could be WLPH FRQVXPLQJ WKHUHIRUH LQ WKLV UHVHDUFK TXDOLWDtive surveys were considered in order to accelerate these calculations, an average base set is used in this VWXG\ $FFRUGLQJO\ % /<3 * ZDV XVHG LQ RUGHU to optimize the structures, stability of wave function, frequency, Energy correction to the basis set superposition error (BSSE) and thermochemistry of calculations, for the purpose of these calculations, Gaussian VRIWZDUH IRU /LQX[ RSHUDWLQJ V\VWHP DQG D TXDG FRUH &38 HTXLSSHG 3& ZHUH XVHG > @ In this article, nitrogen-doped single wall zigzag QDQRWXEHV ZHUH DSSOLHG WR WKH VWXGLHV DQG DQDO\ses. The structure is drawn by HyperChem software.

In order to prevent the effect of open end of single wall carbon nanotubes, both ends of the nanotubes were saturated by hydrogen atoms, to prevent any errors in complete optimization and frequency calculaWLRQV > @ 0DMRU FDOFXODWLRQV DUH DERXW RSWLPL]DWLRQ of various CNT structures and the CNT adjacent to H26 DQG &22 gases which lead to interactional energy calculations for adsorption. Adsorption energy calcuODWLRQV IRU HDFK VLWH LV GHÂżQHG DV IROORZV E ads

E (gas nanotube) E gas E nanotube

(1)

From among the calculations, electrical conductivity calculation can be mentioned. Energy gap can be a criteria and indicator of electrical conductivity, which is GHÂżQHG DV 'E

E /802 E +202

(2)

A less energy gap leads to a more electrical property.

The value of enthalpy changes in the physical surface DGVRUSWLRQ LV FRPPRQO\ LQ WKH UDQJH RI WR NFDO PRO ZKLFK LV VLPLODU WR WKH YDOXH RI JDV OLTXLGLW\ > @ 7KLV TXDQWLW\ LV GHÂżQHG DV 'H q298

ÂŚ 'H

3U RG

q f

ÂŚ 'H

5HDF

q f

(3)

In summary, the structures of NCNT, formed by the substitution of one nitrogen atom with one of the carbon atoms in CNT, was analyzed. Then the interaction between acidic gases and NCNT was studied through selection of a proper structure.

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Figure 1: a) (Structure 1): nitrogen is located in up-edge position; b) (Structure 2): nitrogen is substituted beWZHHQ FDUERQ DWRPV LQVLGH WKH QDQRWXEH F 6WUXFWXUH 6WRQH :DOO GHÂżFLW > @ G 6WUXFWXUH

nitrogen is located in down-edge.

3. RESULTS AND DISCUSSION 3.1. Evaluation of different structures for NCNT With regard to different positions of carbon atoms on nanotube and also energy of nitrogen ions in substitution, six different structures were obtained for NCNT [26]. Among these structures, four main structures have been considered. These four structures are shown in Figure 1 for NCNT [27].

Structural optimization calculations are made for all WKH VWUXFWXUHV LQ )LJXUH 7KHQ WKH FKDQJHG DQG transformed properties such as Energies of Structures were analyzed and evaluated. Table 1 presents a summary of some electron properties such as total energy, relative energy, energy gaps and dipoles moment for NCNT and their differences with CNT. Nitrogen LV PRUH HOHFWURQHJDWLYH WKDQ FDUERQ DERXW DQG because of this fact, some changes are found in bond length and bond angles in NCNT, and its structure is going to be changed from the initial structure. These changed and transformed structures, due to adding Nitrogen atom, are called Bamboo like structures, which

are apparent especially in the structures of NCNT [27]. $FFRUGLQJ WR WKH GHÂżQLWLRQ RI HQHUJ\ FRQWHQW WKH ORZer the level of energy for a structure, the more stable is that structure, and it is considered as the main and optimum structure. According to Table 1, structure 1 has the lowest energy content, so it is the most stable structure. The highest level of energy and therefore the most unstable structure belongs to structure 3. In order WR ÂżQG WKH GHVLUHG VWUXFWXUH ZLWK WKH KLJKHVW OHYHO RI stability and synthesis feasibility, more detailed calFXODWLRQV DUH UHTXLUHG 2QH RI WKH PRVW LPSRUWDQW DQG XVHIXO FDOFXODWLRQV LQ WKLV ÂżHOG LV WKH IUHTXHQF\ DQG thermochemistry calculation. After calculation, there was no imaginary frequency, so these structures do not belong to transition states, and all of the structures are stable and feasible. In Table 2, a summary of results obtained from frequency calculations is provided. In empirical syntheses, obtained values for abundance of WKHVH VWUXFWXUHV VKRZV WKDW SHUFHQWV RI WKHVH VWUXFWXUHV UHODWHV WR VWUXFWXUH VWUXFWXUH LQFOXGHV SHUFHQWV VWUXFWXUH FRQVLVWV RI SHUFHQWV DQG DERXW percent belongs to other types of structure [28]. With

Table 1: 6XPPDU\ RI SURSHUWLHV DQG VSHFLÂżFDWLRQV DERXW 1&17 VWUXFWXUHV DQG &17

Structure

Total Energy (Hartree)

5HODWLYH Energy

Dipole Moment (Debye)

+202 (Hartree)

/802 (Hartree)

Energy Gap (eV)

Structure 1

Structure 2 Structure 3 6WUXFWXUH &17

-1926.779 -1926.797

3.31 2.16

1.117

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Table 2: Summary of results obtained from frequency calculation.

Structure

Î&#x201D;UÂ&#x192;tot

Î&#x201D;HÂ&#x192;tot

Î&#x201D;GÂ&#x192;tot

Structure 1

Structure 2

-1926.3818

Structure 3

6WUXFWXUH

+\GURJHQ 6XOÂżGH Carbon Dioxide NCNT & H2S 1&17 &22

-399.3379

regard to the high abundance of structure 2 and its low energy difference with structure 1, structure 2 is considered as the main and optimum structure in order to evaluate the interactions between acidic gases and this structure.

3.2. Different positions of gases adjacent to NCNT *DV Ă&#x20AC;RZ D FRPSOHWHO\ DFFLGHQWDO PRYHPHQW VR LW LV not possible to say exactly in what positions the gasHRXV PROHFXOHV DUH ORFDWHG 3DVVLQJ JDVHV WKURXJK internal or external wall of the CNTs, their accidental movements, as well as the existence of different atoms such as carbon, nitrogen, sulfur and oxygen

D

will lead to different and various interactions between them [29]. So in order to have a detailed calculation all possible positions were considered. hydrogen sulÂżGH JDVHRXV PROHFXOHV ZLWK & Y V\PPHWU\ ZKLFK LWV PDLQ D[LV QDPHO\ & D[LV LV DORQJ ZLWK = D[LV ZLOO make three main positions for interaction with the main axis of nano tube which pass through the center of nano tube. Figure 2-a depicts these positions as well as the three main interactions between H2S and 1&17 LQ WZR YLVLRQV > @ &DUERQ GLR[LGH JDVHRXV PROHFXOH ZLWK 'Â&#x2019;K V\PPHWU\ LV OLQHDU VR WKHUH DUH two main interaction positions as shown in Figure 2-b. :LWK UHJDUG WR WKH & D[LV D Â&#x192; URWDWLRQ DURXQG WKLV

E

Figure 2: a) Three main positions of interactions between H2S and structure 2 of NCNT; b) Two main interaction positions between CO2 and structure 2 of NCN.

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axis will lead to the formation of the initial structure of WKH PROHFXOH VR WKH URWDWLRQ UDQJH VKRXOG EH GHÂżQHG EHWZHHQ Â&#x192; DQG Â&#x192; 7KHUHIRUH WKH VWUXFWXUHV RI WKH URWDWLRQ DQJOHV RI Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; Â&#x192; DQG Â&#x192; ZHUH FRQVLGHUHG LQ WKLV VWXG\ ,Q RUGHU WR HYDOXDWH WKH YDULRXVO\ GHÂżQHG SRVLWLRQV LW ZDV necessary to do a complete optimization by a proper method in order to obtain the balanced distances of gaseous molecules from nanotubes. Then, in order to evaluate the rotations and consider different interacWLRQ SRVLWLRQV VLQJOH SRLQW 63 HQHUJ\ FDOFXODWLRQ was used which did not change the structure. Therefore, it was possible to rotate the gaseous molecule in proper directions and to calculate their related energies for their positions. +2S data analyses 2EWDLQHG GDWD IURP WKH 63 URWDWLRQ HQHUJ\ FDOFXODWLRQV IRU GLIIHUHQW SRVLWLRQV RI K\GURJHQ VXOÂżGH DGMDFHQW WR NCNT are shown in Figure 3. The main parameter in this evaluation is the corrected adsorption energy, Figure 3-a. The corrected adsorption energy includes adsorption energy and correction of energy obtained from the superposition error of the basis set (BSSE).

3RVLWLRQV KDYH SRVLWLYH DGVRUSWLRQ YDOXHV LQ DOO DQJOHV VR WKH\ DUH D OLWWOH XQVWDEOH 3RVLWLRQ LQ Â&#x192; WR Â&#x192; KDYH D JRRG DGVRUSWLRQ YDOXH DQG SRVLWLRQ LQ Â&#x192; WR Â&#x192; KDYH VWDEOH OHYHOV RI DGVRUSWLRQ *HQHUDOO\ energy differences between different positions and energy barrier in rotations are low. Figure 3-d shows the values of energy gaps for adsorptions in different positions. Energy gaps are close in all the three positions, but in general the energy gaps for position 2 are less and the one for position 3 is more than other positions.

So the electrical conductivity in position 2 is more than the other two positions. The changes in dipole moment has been shown in Figure 3-e. Generally the value of dipole momentum for position 2 is more than the other positions. Data obtained from the changes in the distance of H2S gas from NCNT, is provided in Figure 3-f. The most stable energy belongs to a balDQFHG GLVWDQFH HTXDO WR c ZKLFK KDV DERXW D difference from the obtained value for complete optiPL]DWLRQ DQG LI WKH SRLQWV DUH FRQVLGHUHG ZLWK VKRUWHU GLVWDQFHV WKHQ WKLV HUURU ZLOO GHFUHDVH WR 7KLV Figure shows the potential energy curve used in the

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geometrical optimization of molecule. A useful comparison is conducted between adsorption energy of H2S on CNT and NCNT, which is provided in Figure 3-c. Adsorption is more stable in NCNT than in CNT. 5HVXOWV REWDLQHG IURP WKH HYDOXDWLRQ RI DGVRUSWLRQ from internal rotation of the gas molecule in NCNT are shown in Figure 3-b. Adsorption of H2S in external wall of NCNT is more effective in comparison to its adsorption in internal wall.

3.4. CO2 data analyses )LJXUH D VKRZ WKH 'DWD REWDLQHG IURP WKH FRUUHFWHG adsorption energy calculations for different positions of carbon dioxide adjacent to NCNT. The lowest level of adsorption energy belongs to position 2 which HTXDOV WR NFDO PRO 7KH WUHQG RI FKDQJHV RI WKH DGVRUSWLRQ HQHUJ\ LQ SRVLWLRQ LV VLJQLÂżFDQW ZKLFK LV due to the change in the interaction of oxygen and nitrogen in different rotations. For both of the positions the most stable condition was obtained when there was an interaction between carbon and nitrogen. In the rotations of both positions, no negative stable adsorpWLRQ ZDV IRXQG )LJXUH G SUHVHQWV WKH GDWD REWDLQHG from the energy gaps. The lowest energy gap is in Â&#x192; DQG WKH KLJKHVW HQHUJ\ JDS LV LQ Â&#x192; LQ SRVLWLRQ 7KH FKDQJHV PDGH LQ SRVLWLRQ DUH VLJQLÂżFDQW EHFDXVH of the interactions between oxygen and nitrogen atRPV $FFRUGLQJ WR )LJXUH H GLSROH PRPHQWV IRU DOO of angles in position 1 are more than dipole moments LQ SRVLWLRQ )LJXUH E VKRZV WKH GDWD REWDLQHG IURP FKDQJHV LQ WKH GLVWDQFHV EHWZHHQ &22 and NCNTs. the lowest energy found in the balanced distance equals to c ZKLFK KDV DERXW HUURU LQ FRPSDULVRQ WR WKH GDWD REWDLQHG IURP FRPSOHWH RSWLPL]DWLRQ )LJXUH F provides a comparison between adsorption energy on &22 RQ &17 DV ZHOO DV 1&17V $GVRUSWLRQ RI &22 is more stable in NCNTs than in CNT. According to FigXUH I DGVRUSWLRQ RI &22 inside the NCNTs is often neither effective nor useful. &RPSDULVRQV RI +2S and CO2 adsorptions Does NCNT as a separator catalyst show a better reaction to the separation of H26 RU WKDW RI &22 from sour gases in the sweetening process? The answer to this question is obtained from the analysis and evaluation of the comparison between adsorption energy of

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Figure 3: The changes of corrected adsorption energy versus the rotations of H2S at different positions on a) the external; b) the internal walls of the structure 2 of NCNT; c) The comparison between adsorption energies of H2S on external wall of CNT and NCNT; the changes of d) energy gap; e) dipole moment versus the rotations of H2S at different positions on the external walls of the structure 2 of NCNT and f) The changes of adsorption energy of H2S vs. the distance of the molecule from NCNT.

the desired gases. For H26 DQG &22 the best adsorpWLRQV ZHUH IRXQG LQ SRVLWLRQ ,Q )LJXUH D LQGLFDWHV a comparison between the adsorption energy of both gaseous molecules on NCNTs resulting from the rotation. Generally, the adsorption of H2S on NCNT is PRUH HIIHFWLYH WKDQ WKDW RI &22. There is a negligible 1 kcal/mol difference between the adsorption energies for both gases. A comparison between the adsorption energies of these two gaseous molecules on normal &17 LV SURYLGHG LQ )LJXUH E $GVRUSWLRQV RI ERWK

gases on CNT are weak and unstable. Therefore, existence of nitrogen in the structure of CNT leads to an increase in the adsorption of H26 DQG &22 gases. The YDOXH RI Çť+ Â&#x192; IRU WKH DGVRUSWLRQ RI +26 DQG &22 is DQG NFDO PRO UHVSHFWLYHO\ $GVRUSWLRQ SURcess is thermodynamically desirable.

3.6. Electrostatic potential Electrostatic potential or electric potential energy surIDFH (3(6 LQGLFDWHV WKH HOHFWULF FKDUJH GLVWULEXWLRQ

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Figure 4: The changes of corrected adsorption energy versus the rotations of CO2 at different positions on a) the external; b) the internal walls of the structure 2 of NCNT; c) The comparison between adsorption energies of CO2 on external wall of CNT and NCNT; The changes of d) energy gap; e) dipole moment versus the rotations of CO2 at different positions on the external walls of the structure 2 of NCNT and f) The changes of adsorption energy of CO2 vs the distance of the molecule from NCNT.

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Figure 5: The Comparison between adsorption energies of H2S and CO2 on a) NCNT and b) CNT.

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Figure 6: A feature of the EPES for bare NCNT obtained from MultiWFN.

around the system. This knowledge instruct to identify the probable positions for interaction or/and reaction. $ IHDWXUH RI WKH (3(6 IRU EDUH 1&17 KDV EHHQ GHSLFWed in Figure 6 which shows the positive electrostatic potential dominates around the tube and the minimum electrostatic potential presents on the nitrogen atom.

So this area has more willing for interaction with the acidic gases from the positive electrostatic potentials zoon. This zoon is from the hydrogen atoms for H2S DQG IURP WKH FDUERQ DWRP IRU &22.

static, and about H2S/NCNT because of more negative YDOXH IRU + LQ WKH %&3 WKDQ &22/NCNT, the interaction is Vander Waals.

3.8. Density of states 7KH FRPSDULVRQ RI WKH GHQVLW\ RI VWDWHV '26 IRU CNT and NCNT has been presented in Figure 7-a. This FDOFXODWLRQ LV GRQH E\ WKH 0XOWL:)1 VRIWZDUH 2SHQ VRXUFH VRIWZDUH RQ /LQX[ 7KH )LJXUH VKRZV WKH '26 between the valance bond and conduction bond is not zero and states that both structures are semiconducWRUV 7KH HQHUJ\ JDS IRU WKH V\VWHPV LV DQG ev, respectively, which put on for the semiconductor ranges. In the present of nitrogen atom in the tube the HQHUJ\ JDS GHFUHDVHV DERXW HY PHDQV PRUH HOHFWULF FRQGXFWLYLW\ WKDQ &17 EXW QR FKDQJHV LQ WKH '26 LQ YDODQFH ERQG DQG PRUH '26 LQ WKH FRQGXFWLRQ ERQG So it is expected that NCNT has less electric conductivity than CNT. Fig 7-b shows that the present of the acidic gases on the CNT nanotubes causes to decrease WKH HQHUJ\ JDS DERXW HY DQG FKDQJH WKH '26 LQ the conduction bond. In addition the differences be-

47$,0 DQDO\VLV 7KH REWDLQHG UHVXOWV DERXW WKH LGHQWLÂżFDWLRQ RI WKH FULWLFDO SRLQWV &3 DQG ERQGLQJ SDWKZD\ WKURXJK $,0 VRIWZDUH LQFOXGLQJ WKH W\SH RI FULWLFDO SRLQW electron density (U /DSODFLDQ '2U) and electron Hamilton (H) have been collected in Table 3 [31]. By SD\LQJ DWWHQWLRQ WR WKH SRVLWLYH YDOXHV IRU WKH /DSODcian it can be predicted the weak interactions between both H26 DQG &22 gases with the NCNT. In other words because of low values for U and H for the two FULWLFDO SRLQWV RI &22/NCNT the interaction is electro-

Table 3: Results of atoms in molecule (AIM) calculations about the critical points for H2S/NCNT and CO2/NCNT systems.

System H2S/NCNT &22/NCNT

AIM NCNT C C N C

&3 gas H H C 2

type (3, -1) (3, -1) (3, -1) (3, -1)

name %&3 %&3 %&3 %&3

Ď

â&#x2C6;&#x2021;2Ď

H

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Figure 7: Density of states (DOS) for the CNT and NCNT bare and the adsorbed gases systems.

WZHHQ WKH '26 IRU EDUH &17 DQG JDV &17 DUH KLJK ZKLFK OHDGV WR XVH WKH V\VWHP IRU WKH LGHQWLÂżFDWLRQ RI the gases. Because of the similar differences for the '26 RI &22/CNT and H2S/CNT they canâ&#x20AC;&#x2122;t be used WKH WXEH IRU LGHQWLÂżFDWLRQ RI WKH JDV VLPXOWDQHRXVO\ 7KH FDOFXODWHG RI '26 IRU EDUH 1&17 DQG JDV 1&17 has been shown in Figure 7-c which differs from the gas/CNT systems. All of the three systems have similar energy gap and the differences between them are LQÂżQLWHVLPDO DERXW HY EXW '26 IRU ERWK YDODQFH and conduction bond is about similar. So it canâ&#x20AC;&#x2122;t be XVHG WKH 1&17 IRU LGHQWLÂżFDWLRQ RI WKH DFLGLF JDVHV 7KH SHUIRUPDQFH RI WKH &17 LQ WKH LGHQWLÂżFDWLRQ RI the gases is higher than NCNT.

4. CONCLUSIONS $GVRUSWLRQ RI K\GURJHQ VXOÂżGH DQG FDUERQ GLR[LGH gases on NCNT is more desirable in comparison to WKHLU DGVRUSWLRQV RQ &17 2EWDLQHG UHVXOWV UHYHDO WKDW existence of Nitrogen in the structure of CNT leads to an increase in the adsorption of H26 DQG &22. Ad-

sorption of H26 DQG &22 gases on the external wall of NCNT is better than their adsorptions on the internal wall. Adsorption of H2S gas on the external wall RI 1&17 LV D ELW EHWWHU WKDQ WKDW RI &22 on it. With regard to data obtained from natural bonding orbital 1%2 FDOFXODWLRQV $GVRUSWLRQ RI ERWK JDVHV DUH electrostatic, and there are no bonds between gaseous atoms and NCNT. Adsorption of both gases is desirable in terms of thermodynamic data. Corrections of energy are negligible based on the superposition error of basis set for both gases. It is suggested to consider correction values of energy for a better evaluation of adsorption energies. The frontier orbitals are similar in WKH &17 EDUH DQG &22 &17 KRZHYHU +2S leads to a GHFUHDVH LQ WKH +202 RUELWDO $GVRUSWLRQ RI WKH &22 and H2S gases on the NCNT does not obviously affect WKH RUELWDOV DQG '26 RI WKH EDUH V\VWHPV

ACKNOWLEDGEMENT This research was in full supported by a grant from 3D\DPH 1RRU 8QLYHUVLW\ 318

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/ .RKO 1LHOVHQ *DV 3XULÂżFDWLRQ WK HG +RXVWRQ *XOI 3XEOLVKLQJ &R 3DQ < +DEJRRG + : J. Chem. Eng., 56 (1978), 197.

'HYDL , 'HOXQFH 5 Water Environ. Res., 71

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0 /HRQRU &RQWUHUDV DQG 5 5R]DV Nitrogen-Containing Carbon Nanotubes: A Theoretical Approach ,Q 7HFK 3XEOLVKHU & (ZHOV 0 *OHUXS DQG 9 .UVWLF Nitrogen and Boron Doping in Carbon Nanotubes, AmeriFDQ 6FLHQWLÂżF 3XEOLVKHUV 0 5 6RQDZDQH DQG % - 1DJDUH Study of Adsorption Properties of O2, CO2, NO2 and SO2 on Si-doped Carbon Nanotube Using Density Functional Theory, International Conference on ApSOLHG 3K\VLFV DQG 0DWKHPDWLFV ,&$30

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54

ISSN Print: 2251-8533 ISSN Online: 2322-4142

International Journal of Bio-Inorganic Hybrid Nanomaterials Low Temperature Hydrothermal Synthesis and Characterization and Optical Properties of Sr5Nb4O15 â&#x20AC;&#x201C; Nb2O5 Nanocomposite Shahin Khademinia1, Mahdi Behzad2*, Abdolali Alemi3, Mahboubeh Dolatyari4 1 2

Ph.D., Department of Chemistry, Semnan University, Semnan 35351-19111, Iran

Associate Professor, Department of Chemistry, Semnan University, Semnan 35351-19111, Iran

3

Professor, Department of Inorganic Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran

4

Associate Professor, Laboratory of Nano Photonics & Nano Crystals, School of Engineering-Emerging Technologies, University of Tabriz, Tabriz, Iran

5HFHLYHG 'HFHPEHU $FFHSWHG )HEUXDU\

ABSTRACT 6U 1E 2 Âą 1E 2 QDQRFRPSRVLWHV ZHUH V\QWKHVL]HG LQ DQG 0 .2+ DTXHRXV VROXWLRQV YLD D QRQ VWRLFKLRPHWULF 6U 1E PRODU UDWLR K\GURWKHUPDO PHWKRG DW Â&#x192;& IRU K 6 DQG 6 UHVSHFWLYHO\ 6U 123 DQG 1E 2 ZHUH XVHG DV UDZ PDWHULDOV 7KH V\QWKHVL]HG QDQRPDWHULDOV ZHUH FKDUDFWHUL]HG E\ SRZGHU ; 5D\ GLIIUDFWLRQ 3;5'

WHFKQLTXH ,W ZDV IRXQG WKDW 6U 1E 2 KDV EHHQ FU\VWDOOL]HG LQ KH[DJRQDO FU\VWDO VWUXFWXUH ZLWK VSDFH JURXS 3 P 1E 2 ODWWLFH SDUDPHWHUV ZHUH DOVR IRXQG DV D c E c DQG F c DQG D c E c DQG F c ZLWK J Â&#x192; UHVSHFWLYHO\ IRU WKH RUWKRUKRPELF DQG PRQRFOLQLF FU\VWDO VWUXFWXUHV 7KH PRUSKRORJLHV RI WKH V\QWKHVL]HG PDWHULDOV ZHUH VWXGLHG E\ ÂżHOG HPLVVLRQ VFDQQLQJ HOHFWURQ PLFURVFRSH )(6(0

7KH )(6(0 LPDJHV VKRZHG WKDW WKH 6 DQG 6 QDQRFRPSRVLWHV KDG Ă&#x20AC;RZHU DQG SODWH OLNH VWUXFWXUHV UHVSHFWLYHO\ 8OWUDYLROHWÂą9LVLEOH 89 9LV VSHFWUD DQDO\VHV VKRZHG WKDW WKH V\QWKHVL]HG QDQRFRPSRVLWHV KDG VWURQJ OLJKW DEVRUSWLRQ SURSHUWLHV LQ WKH XOWUDYLROHW OLJKW UHJLRQ )7,5 VSHFWUD RI WKH REWDLQHG QDQRPDWHULDOV ZHUH DOVR VWXGLHG &HOO SDUDPHWHU UHÂżQHPHQWV RI WKH V\QWKHVL]HG QDQRFRPSRVLWHV ZHUH DOVR LQYHVWLJDWHG Keyword: 6U 1E 2 +\GURWKHUPDO 0HWKRG 3;5' 1DQRFRPSRVLWH 2SWLFDO 3URSHUW\ &HOUHI

1. INTRODUCTION Ceramics with general formula A B 2 or AmBPĂ­ 23m represent cubic perovskite structures. They are called FDWLRQ GHÂżFLHQW SHURYVNLWHV DQG DUH VXEMHFW RI LQWHUHVW because of their properties such microwave dielectric [1], high relative permittivity, and low temperature FRHIÂżFLHQW RI UHVRQDWRU IUHTXHQF\ > @ $PRQJ WKHP (*) Corresponding Author - e-mail: mbehzad@semnan.ac.ir

Sr Nb 2 has been investigated for diamagnetic insuODWRU > @ 6HYHUDO PHWKRGV KDYH EHHQ UHSRUWHG IRU WKH synthesis of Sr Nb 2 nanomaterials such as reaction VLQWHULQJ SURFHVV > @ VROLG VWDWH UHDFWLRQ > DQG @ pyrolysis, and calcinations [7]. In the present study, a hydrothermal route was employed successfully for the

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54

synthesis of nanostructured Sr Nb 2 Âą 1E22 comSRVLWHV XVLQJ 6U 123)2, Nb22 DQG .2+ DV UDZ PDWHrials. To the best of our knowledge, there is no report on the synthesis of nanostructured Sr Nb 2 Âą 1E22 FRPSRVLWHV E\ WKLV PHWKRG 7KH HIIHFWV RI .2+ FRQFHQWUDWLRQ RQ WKH ÂżQDO SURGXFWV LQ SKDVH FRPSRVLWLRQ and particle morphology were investigated, and the band gap energy of the as-prepared nanocomposites samples was initially estimated from UV-Visible specWUD %HVLGHV )7,5 VSHFWUD RI WKH V\QWKHVL]HG QDQRcomposites were also studied.

2. EXPERIMENTAL 0DWHULDOV DQG PHWKRGV $OO FKHPLFDOV LQFOXGLQJ 6U 123)2, Nb22 DQG .2+ were of analytical grade and were obtained from commercial sources (Merck, Germany) and were used ZLWKRXW IXUWKHU SXULÂżFDWLRQV 7KH QDQRPDWHULDOV 61 and S2 were synthesized via hydrothermal method in DQG 0 .2+ DTXHRXV VROXWLRQV UHVSHFWLYHO\ 3KDVH LGHQWLÂżFDWLRQV ZHUH SHUIRUPHG RQ D SRZGHU ; 5D\ GLIIUDFWRPHWHU ' 6LHPHQV $* 0XQLFK *HUmany) using CuKÄŽ radiation. The morphology of the REWDLQHG PDWHULDOV ZDV H[DPLQHG ZLWK D ÂżHOG HPLVsion scanning electron microscope (Hitachi FE-SEM PRGHO 6 $EVRUSWLRQ VSHFWUD ZHUH UHFRUGHG RQ D -HQD $QDO\WLN 6SHFRUG $QDO\WLN-HQD 8. :HPEOH\ 8. $OVR )7,5 VSHFWUD ZHUH UHFRUGHG RQ D 7HQsor 27 (Bruker Corporation, Germany). Cell parameWHU UHÂżQHPHQW ZDV UHSRUWHG E\ FHOUHI VRIWZDUH YHUVLRQ /DERUDWRLUH GHV 0DWHULDX[ HW GX *pQLH 3K\VLTXH GH OÂś(FROH 6XSpULHXUH GH 3K\VLTXH GH *UHQREOH

+\GURWKHUPDO V\QWKHVLV RI 6U5Nb4O15- Nb2O5 nanocomposites ,Q W\SLFDO V\QWKHWLF H[SHULPHQWV LQ ERWK PHWKRGV J PPRO RI 6U 123)2 (Mw = 211.62 g mol-1) and J PPRO RI 1E22 0Z J PRO-1) ZHUH XVHG 7KH UDZ PDWHULDOV ZHUH DGGHG WR P/ RI KRW DTXHRXV VROXWLRQV RI RU 0 .2+ 61 and S2 UHVSHFWLYHO\ XQGHU PDJQHWLF VWLUULQJ DW Â&#x192;& 7KH UHVXOWDQW VROXWLRQV ZHUH VWLUUHG IRU IXUWKHU PLQ DQG WUDQVIHUUHG WR D P/ 7HĂ&#x20AC;RQ OLQHG VWDLQOHVV VWHHO DXWRFODYH 7KH DXWRFODYH ZDV VHDOHG DQG KHDWHG DW Â&#x192;&

Behzad M et al

IRU K :KHQ WKH UHDFWLRQ ZDV FRPSOHWHG LW ZDV cooled to room temperature by water immediately.

The prepared powder was washed with distilled water DQG GULHG DW Â&#x192;& IRU PLQ XQGHU QRUPDO DWPRspheric conditions and a cream like powder was collected for further analyses.

3. RESULTS AND DISCUSSION 3.1. Powder X-Ray diffraction analysis 7KH ; 5D\ GLIIUDFWLRQ SDWWHUQV RI WKH 6U Nb 2 Âą 1E22 nanocomposites samples are reported in Figures 1 and )LJXUH VKRZV WKH ; 5D\ GLIIUDFWLRQ ;5' DQDO\sis of Sr Nb 2 VDPSOH REWDLQHG LQ WKH Č&#x2122; Č&#x2122; JHRPetry with Cu-KÄŽ radiation. The results showed that the

Figure 1: PXRD patterns of the S1. The bars show the Bragg's positions for a) Sr5Nb4O15, b) orthorhombic Nb2O5 and c) monoclinic Nb2O5.

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54

Figure 2: PXRD patterns of the S2. The bars show the Bragg's positions for a) Sr5Nb4O15, b) orthorhombic Nb2O5 and c) monoclinic Nb2O5.

pattern had two Sr Nb 2 and Nb22 as main phases.

Sr Nb 2 structure was detected with hexagonal crysWDO VWUXFWXUH ZKLFK KDV EHHQ FU\VWDOOL]HG LQ WKH 3 P space group [1]. Two different crystal structures were observed for Nb22 in both (S1) and (S2 VDPSOHV QDPHly orthorhombic and monoclinic crystal structures.

Nb22 ODWWLFH SDUDPHWHUV ZHUH IRXQG DV D c E c DQG F c DQG D c E c

DQG F c ZLWK Č&#x2013; Â&#x192; UHVSHFWLYHO\ IRU WKH orthorhombic and monoclinic crystal structures. It LV DOVR FOHDU WKDW DFFRUGLQJ WR WKH 3;5' SDWWHUQ WKH Sr Nb 2 phase formation compared to Nb22 phase LV DERXW )LJXUH VKRZV WKDW ZLWK FKDQJLQJ WKH synthesis condition, there is still a mixture of two phases including Sr Nb 2 and Nb22 . The measured ;5' GDWD DUH LQ DJUHHPHQW ZLWK WKRVH RI UHSRUWHG ;5' IRU 6U Nb 2 nanomaterials [1]. According to WKH 3;5' SDWWHUQV LW ZDV IRXQG WKDW WKH 6U Nb 2 phase formation compared to Nb22 LV DERXW 6R it is clear that there is an optimization in Sr Nb 2 SKDVH IRUPDWLRQ ZLWK LQFUHDVLQJ .2+ FRQFHQWUDWLRQ Compared to the nanomaterials of the hydrothermally synthesized Sr Nb 2 (S1), the diffraction lines in the SRZGHU ;5' SDWWHUQV RI WKH 6U Nb 2 Âą 1E22 nanocomposites (S2 KDV VKLIWHG WR ORZHU Č&#x2122; YDOXHV DQG therefore to the higher d values. So, using the peak ZLWK PLOOHU LQGLFHV RI D EOXH GLIIUDFWLRQ OLQH VKLIW RI Çť Č&#x2122; Â&#x192; 6 Âą Â&#x192; 61 Â&#x192; ÇťG c 6 Âą c 61 c DUH FDOFXlated via Braggâ&#x20AC;&#x2122;s equation. So there is an expansion in the unit cell according to the calculated data.

7DEOH VKRZV WKDW UHÂżQHG FHOO SDUDPHWHU GDWD IRU (S1) and (S2), respectively. The data showed that with changing the synthesis rout, the cell parameters for (S2) were larger than those of (S1). So there should be an expansion in the unit cell. It is in agreement with the interplanar spacing data calculated via Braggâ&#x20AC;&#x2122;s equation.

0RUSKRORJ\ RI WKH PDWHULDOV Figure 3 shows typical FESEM images of the hydrothermally synthesized Sr Nb 2 Âą 1E22 nanocomSRVLWHV LQ 0 .2+ VROXWLRQ 61). From the typical FESEM images of S1 DW ORZ PDJQLÂżFDWLRQ LQ )LJXUHV 3a and b, it was found that the morphology of the REWDLQHG PDWHULDOV ZDV LQ Ă&#x20AC;DNH OLNH IRUP $W KLJKHU

Table 1: Cell parameter data for samples 1 and 2.

Cell parameter

Standard Sample [3]

Sr Nb 2 (S1)

Sr Nb 2 (S2)

a

9.9136

b

c

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54

Behzad M et al

Figure 3: FESEM images of S1.

PDJQL¿FDWLRQ LQ )LJXUHV F DQG G LW LV FOHDU WKDW WKH WKLFNQHVV VL]HV RI WKH Ã&#x20AC;DNHV DUH LQ WKH UDQJH RI DERXW WR QP )LJXUH VKRZV W\SLFDO )(6(0 LPDJHV RI WKH K\GURthermally synthesized Sr Nb 2 ± 1E22 nanocom-

SRVLWHV LQ 0 .2+ VROXWLRQ 62). FESEM images of S2 LQ )LJXUHV D DQG E VKRZHG WKDW WKH PRUSKRORJ\ RI WKH REWDLQHG PDWHULDOV ZDV LQ D PL[WXUH RI Ã&#x20AC;RZHU VWUXFWXUHV IURP URGV DV SHWDOV 7KH VPDOO Ã&#x20AC;RZHU VWUXFtures from the very small plates as petals crossed each

Figure 4: FESEM images of S2.

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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54

Figure 5: FTIR spectra of S1 and S2.

RWKHU IRUPHG WKH RWKHU OLNH Ă&#x20AC;RZHU VWUXFWXUHV )LJXUHV F DQG G VKRZ WKDW WKH OHQJWK VL]HV RI WKH URG VWUXFWXUHV ZDV LQ D UDQJH RI DERXW WR QP 7KH WKLFNQHVV VL]H RI WKH URGV ZDV DERXW WR QP 6R the images showed that the size ranges of the obtained materials were nearly non-homogeneous. Also, Figure 3d showed that the thickness size of the very small SODWHV ZDV LQ D UDQJH RI DERXW WR QP )LJXUH VKRZV WKH )7,5 VSHFWUD RI WKH V\QWKHVL]HG S1 and S2 QDQRFRPSRVLWHV 7KH )7,5 VSHFWUD REtained on the samples S1 and S2 show main absorpWLRQV EDQGV DW DURXQG FP-1 DQG FP-1, respectively, that are characteristic for the synthesized Sr Nb 2 Âą Nb22 QDQRFRPSRVLWHV 7KH EDQGV DW DURXQG DQG FP-1 are assigned to monoclinic Nb22 and the EDQGV DW DURXQG FP-1 is attributed to orthorhombic Nb22 > @ ,W LV D FRQÂżUPDWLRQ RI WKH FR H[LVWHQFH of both orthorhombic and monoclinic Nb22 in the synthesized nanocomposite that is in agreement with WKH PHDVXUHG 3;5' GDWD 7KH ZHDN EDQGV DW DURXQG DQG FP-1 are attributed to the bending mode of H22 PROHFXOHV 7KH EDQG DW DURXQG FP-1 is asVLJQHG WR 6U Âą 2 YLEUDWLRQ > @ Figure 6 shows the UV-Vis spectra of the synthesized nanocomposites. The absorption peak positions in both spectra suggest that these materials are wide band gap semiconductors. It is clear in Figure 6a that WKHUH DUH WKUHH DEVRUSWLRQ EDQGV DW DQG D VKRXOGHU DW QP 7KH DEVRUSWLRQ HGJH EDQG LV DW DERXW QP DQG VR WKH FDOFXODWHG EDQG JDS LV DERXW H9 +RZHYHU LQ )LJXUH E WKHUH DUH WKH EDQGV DW DQG D ZHDN EDQG DW QP 7KH DEVRUSWLRQ HGJH EDQG LV DW DERXW QP DQG VR WKH FDOFXODWHG band gap is about 3.22 eV that is smaller than that of

D

E

Figure 6: UV-Vis spectra of S1 (a) and S2 (b).

S1. It is not surprising to observe the difference in the optical property because these two specimens have different constituting crystalline phases. However, it is clear that the absorption spectrum shown in Figure D LV DOPRVW OLNH WKDW RI 1E22 that is because of the very large Nb22 /Sr Nb 2 SKDVH UDWLR > @ $OVR LW LV QHDUO\ OLNH WKH RWKHU 6U 1E 2 PL[HG PHWDO R[LGHV DEsorption spectra. However, the band gaps are different from the calculated data in this work [16].

4. CONCLUSIONS In this work, Sr Nb 2 Âą 1E22 nanocomposites were synthesized successfully via hedrothermal methRG 3;5' SDWWHUQV VKRZHG WKDW WKH V\QWKHVLV ZDV successfull. FESEM images showed that the as-synWKHVL]HG PDWHULDOV ZHUH LQ Ă&#x20AC;DNH OLNH 61) and two kind Ă&#x20AC;RZHU OLNH VWUXFWXUHV 62 89 9LV DQG )7,5 VSHFWUD of the synthesized nanocomposites were also investigated to further support the synthesis of the nanocomSRVLWHV &HOO SDUDPHWHU UHÂżQHPHQWV RI WKH V\QWKHVL]HG nanocomposites were also investigated.

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54

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