Photocatalytic microbial removal and degradation of organic contaminants of water using PES fibers

Photocatalytic bacterial removal and dye degradation by polyethersulfone (PES) fibers under visible light is reported here. PES fibers were arranged in a random mesh structure using electro-spinning technique that allows utilization of maximum surface area of the fibers. The influence of concentration of PES polymer, type of solvent and surface chemistry of the fibers on their mechanical properties and photocatalytic activities was investigated. Ratio of solvent (DMF (Dimethylformamide) to NMP (N-Methyl-2-pyrrolidone)) while preparing the PES fibers was found to be crucial in terms of the PES fiber thickness, fluid flux, mechanical strength and hydrophobicity of the fibers. The as-prepared PES fibers showed considerable amount of OH[rad] radical generation under visible light excitation resulting in efficient degradation of model dye contaminant methylene blue (MB) and disinfection of model bacterium Escherichia coli (E. coli). However increased hydrophilicity of the fibers using oxidation treatment resulted in reduction in the generation of OH[rad] radicals showing less photocatalytic activity by the PES fibers. FTIR investigations confirmed no self-destruction of the PES fibers due to the generation OH[rad] radicals indicating potential application of PES fibers as a useful photocatalytic polymer material for bacterial removal and decontamination of water.