PROGRAM 3: SUMMARIES New Engineered Biopolymers and Synthetic Polymers

NO TITLE LEADER & KEY PERSONNEL PROJECT SUMMARIES

P3.1 Engineering of Selective Polypeptide and RAFT Polymers

45 Development of bio-polymer collectors for selective flotation of specific minerals

Leader: Prof Chun-Xia Zhao (UoA)

Key Personnel:

Prof David Beattie (UniSA)

Dr Susana Brito Abreu (UQ)

A/Prof Marta Krasowska (UniSA)

PhD Student: Rupinder Kaur (UniSA)

Highly metal/mineral specific chemicals are not available to the minerals industry. There is potential to achieve this specificity using peptides. A series of peptide variants (monomers, dimers with different linkers) were designed and synthesised based on the phage display method. Silver and silica were used as a model system to demonstrate the binding specificity. The silver binding peptides have binding affinity not only to silver ions, but also to silver particles. Therefore, a separation assay was developed by mixing silver particles and silica particles. The addition of the silver peptide led to the aggregation and sedimentation of silver particles but not silica particles, achieving an exceptionally high separation factor (>1400). The UniSA team studied the silver-binding peptides using a QCM. The adsorption of peptides was evaluated by determining the reversibility of adsorption on silver, giving a hierarchy of binding affinity. Studies were also performed for the peptides on silica, to investigate adsorption selectivity and to assist in interpretation of settling data from UoA.

47 Development of bio-polymer reagents for achieving hydrophobic flocs from hydrophilic clays

Leader: Prof Grant Webber (UON)

Key Personnel: Prof Chun-Xia Zhao (UoA)

Prof George Franks (UOM)

PhD Student: Matthias Orchard (UoA)

This project seeks to develop novel bio-inspired polymers for the processing of waste clay-based suspensions. A protocol has been developed to measure adsorption isotherms on particles using sub-gram quantities of reagent. The synthesis of bio flocculants using a bacteria cell factory has begun and preliminary studies investigating their interactions with model clays systems undertaken. The performance of these bio flocculants for clay agglomeration will now be investigated by measuring adsorption isotherms, dewatering rates, and rheological properties.

46 Development of RAFT polymer collectors for selective flotation of specific minerals

Leader: Prof San H. Thang (Monash)

Key Personnel: Prof Erica Wanless (UON)

A/Prof Liza Forbes (UQ)

PhD Student: Sonia Khandaker (UON)

Bio-inspired collectors based on cardanol, and α -tocopherol (Vitamin E) as new reagents have been designed and synthesised with the aim of improving the froth flotation processes. All these collectors were found to have dual properties - foaming and selectivity for binding specific minerals offering the beneficiation of minerals using fewer reagents. Small-scale qualitative experiments were conducted using xanthate functionalised α -tocopherol-poly(ethylene glycol) (PEG) derivatives. The target mineral (chalcopyrite particles in this instance) was found to attach to the collectors and floated without the addition of frother. The foaming property of α -tocopherol-PEG derivatives was further investigated in a collaboration with UON. The α -tocopherolPEG derivatives as surfactants were applied in the research by UOM on emulsion stabilising studies, UniSA for QCM studies, and UON as reagents for lithium-ion recovery.

48 Development of RAFT polymer reagents for achieving hydrophobic flocs from hydrophilic clays

Leader: Prof San H. Thang (Monash)

Key Personnel: Prof Grant Webber (UON)

Prof George Franks (UOM)

PhD Student: Danesh Perera (Monash)

This project focuses on the synthesis of well-defined RAFT polymers as novel reagents for use in aggregation, agglomeration and flotation in several projects within the Centre. In addition, the project involves the synthesis of new cardanol-based polymer collectors targeting copper-bearing minerals, especially chalcopyrite. Studies on RAFT polymers with xanthate functional groups showed that these polymers were effectively bound not only to the chalcopyrite but also to pyrite surfaces. To improve the selectivity towards chalcopyrite, a novel acyl-thiourea (R-CO-NH-CS-NR1R2) small molecule collector based on cardanol were synthesised and evaluated. The attachment of acyl-thiourea functionality to RAFT polymers is being explored as a comparison to xanthate-based collectors.

Graphic Featured in: RAFT-mediated polymerization-induced self-assembly (RAFTPISA): current status and future directions