Polyethersulfone mixed matrix membrane with abundant sponge pores for high‐separation performance with high flux retention and cycling stability

Abstract In recent years, a series of high‐performance ultrafiltration membranes have been developed, but maintaining high flux and high pollutant retention rate without sacrificing service life remains a long‐standing challenge. In this study, a porous polyethersulfone ultrafiltration membrane enriched with ZIF‐8 and TiO 2 additives is prepared based on a non‐solvent induced phase separation method. During the phase transition process, the addition of organic nanocrystals ZIF‐8 and inorganic nanocrystals TiO 2 delayed the phase transition rate, resulting in the transformation of the polyethersulfone modified membrane from a finger‐like pore structure to a sponge‐like pore structure. Compared to other structures, the sponge‐like modified membrane has a uniform and narrow pore size distribution, fewer surface defects, stable retention performance, and can simultaneously improve membrane permeability and mechanical strength. Therefore, the polyethersulfone modified membrane with a sponge‐like pore structure prepared in this research exhibits high flux for small molecules and good retention rate for large molecules. Long‐term cycling stability tests of the modified membrane shows high retention rate (over 98%), high flux, long service life, and good cycling stability for solute molecules. The study indicates that the prepared polyethersulfone modified membrane has high potential for application in relevant environmental separation processes.