Construction of nanoparticle array membranes by tumour metastasis-inspired self-seeded phase inversion for microplastic wastewater treatment

Abstract In a typical phase inversion-fabricated membrane, the arrangements and sizes of polymers are random, which generates a wide pore size distribution. Larger pores in the membrane result in inadequate rejection of pollutants; therefore, the designed membrane must feature a mean pore size smaller than the theoretical size to achieve high rejection of pollutants. However, the flow resistance of the membrane significantly increases with a reduction in the mean pore size, which considerably decreases the membrane flux. Herein, inspired by tumour metastasis, we present “self-seeded phase inversion (SSPI)”. This technique utilises partial dissolution of polyvinylidene fluoride nanoparticles to produce seed crystals that are uniformly distributed by vacuum filtration to induce non-solvent induced phase inversion (NIPS). Using this process, nanoparticle array membranes with uniform sizes and regular arrangements can be prepared in a simple, controllable, and practical mannerviafiltration at room temperature and NIPS. Because of their narrow pore-size distributions, low pore tortuosities, and low thicknesses, the obtained membranes demonstrate higher fluxes and rejection of microplastics with sizes similar to the pore sizes of the membranes. SSPI provides a facile way to overcome the current constraints of water-treatment membrane technology, which can facilitate the sustainable development of water-treatment membrane technology and has the potential for wider applications.