Enhancing hydrophilicity and permeation flux of chitosan/kaolin composite membranes by using polyethylene glycol as porogen

A novel chitosan/kaolin composite membrane with high flux and enhanced hydrophilicity was prepared by solvent casting and evaporation process in the presence of polyethylene glycol (PEG). The characterization of the as-fabricated membranes indicated that the combined effect of kaolin as reinforcing agent and PEG as porogen into a chitosan matrix showed significant influence on the morphology and hydrophilicity. Highly porous membranes with finger-like structure were obtained. Both size and density of the pores increased with increasing the PEG content from 0 to 3 wt%. The incorporation of the hydrophilic polymeric additive constructed a water channel network and increased the free volume within the composite matrix, contributing to the enhanced filtration performance of the resulting membrane. Additionally, their mechanical, thermal and chemical stability showed a large improvement compared to the unmodified one.