Polyacrylonitrile-based block copolymer ultrafiltration membranes with enhanced antifouling and pollutants removal efficiency

Abstract

Block copolymer-based porous materials have found extensive applications across a broad spectrum of industries. Their customized structures and scalable production capabilities have provided numerous possibilities to design membranes with precise separation properties. In this study, mPEGx-b-PAN block copolymers have been synthesized by incorporating mPEG of varying molecular weights in order to improve the selectivity and the antifouling properties of the resulting ultrafiltration membranes. Microphase separation within mPEG and PAN blocks was dependent on mPEG chain length and block concentration, ultimately leading to the controlled creation of pores in the mPEGx-b-PAN ultrafiltration membrane. Simultaneously, the surface layer thickness of the composite membrane was considerably reduced after adding the block copolymer. The optimized UF_2000–1.0 membrane, prepared by blending 1 % mPEG₂₀₀₀-b-PAN with PAN, exhibited a high permeability of 340.75 ± 22.17 L m⁻² h⁻¹ bar⁻¹ and a BSA rejection rate of over 99 %, effectively separating organic pollutants such as HA, CR, and CB-G250. Furthermore, antifouling tests showed that the mPEG₂₀₀₀-b-PAN/PAN composite membranes exhibited a gradual degradation of permeability during the antifouling stage, with high permeability recovery after backwashing. Therefore, mPEGx-b-PAN block copolymers demonstrate promising potential for membrane separation applications and pave the way for significant advancements in filtration technology.