Constructing Microstructures of Chlorinated Polyvinyl Chloride Microporous Membranes by Non-solvent Induced Phase Separation for High Permeate Flux and Rejection Performance

To obtain the excellent permeate flux, rejection performance and mechanical properties, the chlorinated polyvinyl chloride (CPVC) porous membrane was fabricated on the polyethylene terephthalate (PET) non-woven fabric by non-solvent induced phase separation (NIPS), using Tween80 (polyoxyethylene sorbitan monooleate) as a hydrophilic surfactant to regulate the microstructure of the membrane. Porous skin layer and sub-layer were achieved when 3 wt.% Tween80 was added with a small amount of deionized water as additive, and internal layer consisted of various finger-like holes. The forming mechanism of microstructures was investigated according to the effects of Tween80 molecular chain structure on the viscosity and surface tension of casting solution. Significantly, the modified membranes obviously exhibited higher pure water flux, which was increased by 257 % compared with the pristine membrane. The rejection to ink suspension was over 99 %. Furthermore, the antifouling performance of modified membrane was also greatly improved on account of the above microstructure and more hydrophilic surface. This study provides a new idea for the construction of membrane microstructure and the hydrophilic modification.