Ferroelectric membrane for water purification with arsenic as model pollutant

Membrane filtration is widely applied, but often subject to a trade-off between permeability and selectivity, an inherent challenge in membrane processes. Charged membranes are a promising alternative to address this challenge. Here, ferroelectric BaTiO3 nanoparticles, with a spontaneous electric polarization, were assembled into the traditional polyamide nanofiltration membranes by interfacial polymerization then charged by corona poling. Importantly, charges of ferroelectric BaTiO3 nanoparticles sealed in polymers were hardly affected by ambient aqueous environment. The polarized ferroelectric membrane (TFN-mBTO-E) showed higher permeability (2.4 and 1.5 times) and favorable rejection ratio about 97% for arsenic removal, a strictly controlled contaminant, compared with common membranes and unpolarized TFN-mBTO membranes, due to strong hydrophilicity and increased surface potential derived from ferroelectric charges. Thereby, it could provide new insight into charged membrane, laying a foundation for the application of ferroelectric materials in membrane filtration.