INDIA WATER WEEK 2013 SESSION
“WASTEWATER MANAGEMENT - RECYCLING AND REUSE” PAPER TITLE
“CHLOROPHENOLICS OXIDATION FROM PULP BLEACHING EFFLUENTS USING PHOTOCATALYSIS”
CONTRIBUTORS PARVEEN KUMAR, SATISH KUMAR, NISHI KANT BHARDWAJ e-mail: parveenenv@gmail.com AMITY UNIVERSITY HARYANA , GURGAON (MANESAR)
INTRODUCTION INTRODUCTION Pulp bleaching Use of chlorine – AOX (chloro-organics) Pollution prevention measures:
Pulp bleaching technology improvement Biological treatment Advanced oxidation treatment
(Photocatalysis: UV/TiO2, UV/TiO2/H2O2 , UV/O3/TiO2 etc.)
OBJECTIVES OBJECTIVES Characterization of chlorophenolics generated during bleaching of mixed hardwood kraft pulp using DEPD sequence. Photocatalytic
oxidation
of
chlorophenolics
by
effluent treatment with UV/TiO2 and UV/TiO2/H2O2 processes.
EXPERIMENTAL EXPERIMENTAL Mixed hardwood kraft pulp (K.N. 15) ClO2 produced in-situ from NaClO2 pH adjusted: 1M H2SO4 / 1M NaOH solution NaOH solution: alkaline extraction of pulp Target brightness: 87% ISO with DEPD sequence Chlorine demand (%) = K.N. × K.F. Bleaching performed: 200 g O.D. pulp TiO2 (Fisher Scientific): Anatase (99.97 wt.%), BET surface area - 26.11 m2/g, Particle size - 50-150 nm)
PHOTOCATALYTIC PHOTOCATALYTIC REACTOR REACTOR
RESULTS RESULTS AND AND DISCUSSION DISCUSSION ANALYTICAL CHARACTERISTICS OF THE EFFLUENTS D1 Stage
EP Stage
COD (mg/L)
813
673
BOD (mg/L)
212
168
BOD/COD
0.26
0.25
Color (mg/L Pt-Co)
980
1113
pH
3.3
10.5
AOX (mg/L)
18
15.3
Parameters
CHLOROPHENOLICS CHLOROPHENOLICS OXIDATION OXIDATION FROM FROM DD11 AND AND EEPP STAGE STAGE EFFLUENTS EFFLUENTS USING USING UV/TiO UV/TiO22 AND AND UV/TiO UV/TiO22/H /H22O O22PROCESSES PROCESSES
Chlorophenolics
Initial con. (µg/L)
Removal (%) UV/TiO2
UV/TiO2/H2O2
D1
EP
D1
EP
D1
EP
3-chlorophenol
0.11
1.35
92
56
97
64
4-chlorophenol
0.04
0.02
81
87
96
ND
2,6-dichlorophenol
0.04
ND
86
-----
ND
-----
2,5-dichlorophenol
0.13
0.61
93
89
89
92
2,4-dichlorophenol
0.01
0.02
84
92
91
ND
3,4-dichlorophenol
0.04
0.04
77
75
79
81
4-chloroguaiacol
1.56
4.39
58
52
65
59
2,4,5-trichlorophenol
0.09
0.07
86
87
93
97
4,5-dichloroguaiacol
4.12
6.00
47
46
54
55
CONTINUED…….. CONTINUED……..
Chlorophenolics 2,3,4-trichlorophenol 4,6-dichloroguaiacol 3,6-dichlorocatechol 3,5-dichlorocatechol 3,4,5-trichloroguaiacol 4,5,6-trichloroguaiacol 5,6-dichlorovanillin Tetrachlorocatechol 2,6-dichlorosyringaldehyde Total
Initial con. (µg/L)
Removal (%) UV/TiO2
UV/TiO2/H2O2
D1
EP
D1
EP
D1
EP
0.06 0.03 2.14 0.62 0.01 ND ND 0.25 ND 9.3
0.06 0.06 ND ND ND 0.05 0.06 0.18 0.22 13.1
79 ND 59 83 82 --------83 ----57
84 90 ------------ND 74 90 83 53
93 ND 66 91 ND --------88 ----64
95 95 ------------ND 78 ND 86 61
Removal (%) of chlorophenolics by chemical family for D1 stage effluent
Removal (%) of chlorophenolics by chemical family for EP stage effluent
CHLOROPHENOLICS CHLOROPHENOLICS
REMOVAL REMOVAL
BY BY
CHEMICAL CHEMICAL
Removal (%) of chlorophenolics by number of attached chlorine atoms for D1 stage effluent
Removal (%) of chlorophenolics by number of attached chlorine atoms for EP stage effluent
CHLOROPHENOLICS CHLOROPHENOLICS REMOVAL REMOVAL BY BY NUMBER NUMBER OF OF ATTACHED ATTACHED CHLORINE CHLORINE ATOMS ATOMS
CONCLUSIONS CONCLUSIONS
The experimental findings show that TiO2 photocatalysis is an attractive technique for the oxidation of chlorophenolics from pulp bleaching effluents.
Higher pollutants removal efficiency was achieved with UV/TiO2/H2O2 process as compared with UV/TiO2.
The biodegradability of the effluents improved after photocatalytic oxidation with both the processes. This indicates easy removal of the degradation products during biological treatment.
The photocatalysis, using solar light as an economical light source, may be a potential technology in future for remediation of biorecalcitrant pollutants.
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