Investigation on the rejection of mixed salt solution by g-C3N4 functionalized nanofiltration membrane

Abstract

The use of nanofiltration membrane technologies for seawater desalination is one of the effective ways to solve the shortage of water resources. However, traditional commercial membrane cannot maintain the excellent rejection for a variety of salt ions in mixed salt solutions, while ensuring the excellent permeance flux. In this study, g-C₃N₄ functionalized nanofiltration membranes of special charge distribution on the surface were prepared by interfacial polymerization to investigate the rejection performance of mixed salt solution (Na₂SO₄/NaCl, CaCl₂/NaCl). Compared with the traditional commercial nanofiltration membrane, the polyamide nanofiltration membrane intercalated with g-C₃N₄ has excellent rejection performance of a permeance flux of 50.76 L$\bullet$m⁻² h⁻¹ and 50% retention improvement for both monovalent and divalent ions. In addition, the composite membrane has a good anti-fouling performance in both bovine serum albumin and humic acid solutions.