(351at) Anti-Bacterial Chitosan-Copper Supramolecular Assembly for Coating Thin-Film Composite Membranes

Membrane-based desalination has become a standard practice for providing water for the growing demand. Membranes used in water desalination are prone to Biofouling and approach to mitigate membrane biofouling is at high demand. To impart antibiofouling properties to membranes various approaches has been used. Among these approach metallic biocides, such a silver and copper nanoparticles, has shown promising results. Nonetheless, these particles are prone to dissolution in water. Here we demonstrate the immobilization of copper on Thin Film Composite Reverse Osmosis membrane surface by including copper ions in chitosan complex deposited on the surface. The chitosan-copper chelate was formed by dissolving different concentrations of Copper sulfate in 1000 mg/L Chitosan solution at pH 2.85. The Commercial Thin Film Composite Reverse Osmosis was subjected to oxidizing agent, creating active sites on polyamide for binding with the chitosan-copper complex. After immobilizing the supramolecular complex on membranes, they were cured at 80^oC for 30 minutes. Subsequently, the excess Copper was removed by putting the membrane in 0.1M Sodium hydroxide overnight. The film uniformity, metal ion concentration, metal ion leaching rate, antibacterial performance, and transport properties of the membrane were evaluated. The modified membrane demonstrated anti-bacterial properties, proving that the current scheme is successful in introducing biocides into TFC membranes. Our data suggests that copper ions leach out from the surface, results in the loss of antibacterial activity. Thus, we developed a process for rejuvenation of the surface through post-treatment.

Acknowledgement: Authors acknowledge Indo-US Science and Technology Forum - Water Advanced Research and Innovation Fellowship under which the research work was undertaken and University of Nebraska Lincoln, the host university.