Polymeric nanocomposite membranes for water treatment: a review

Abstract

Water scarcity is a pressing global challenge. Filtration with actual polymeric membranes shows good capability for pollutant separation, but broad applications of polymeric membranes are limited. Filtration can be improved using nanocomposite membranes, which are formed by incorporating nanofillers into polymeric membrane matrixes. The most extensively investigated nanofillers are carbon-based nanoparticles and metal/metal oxide nanoparticles. Here, we review the performance of nanocomposite membranes in antifouling and permeability, their physical and chemical properties and we compare nanocomposite membranes with bare membranes. Nanocomposite membranes generally display better antifouling properties due to the antimicrobial properties of nanoparticles and the reduced roughness of membrane. They also demonstrate higher permeability because of the higher porosity and narrower pore size distribution created by nanofillers. The concentration of nanofillers changes membrane performance, and the optimal concentration depends on both the properties of nanoparticles and the membrane composition. Higher concentrations of nanofillers above the optimal value result in poor performance due to nanoparticle aggregation. Despite intensive research in the synthesis of nanocomposite membranes, most previous efforts are limited to laboratory scale, and the long-term membrane stability following nanofiller leakage has not been extensively investigated.