Improved filtration performance of dye rejection with a novel polyarylate membrane after Cu+ treatment

In this study, a novel cuprous ion (Cu + ) complexed polyarylate (PAR) membrane was developed. Polymers with vary ratios of cinchoninic unit were prepared by copolymerizing of dibenzoic chloride and bicinchoninic acid (BCA) that can coordinate with Cu + . The resultant functional PARs with differing ratios of BCA unit were casting to form ultrafiltration membranes using non-solvent induced phase transition (NIPs) method, then the membrane was treated with Cu + solution to form a metal cross-linking structure, then the membrane pore size was further shrunk. The coordination between Cu + and the PARs containing BCA units were characterized by X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS), it was also calculated and analyzed by simulations and visualizations. Compared with the un-treated membrane, it can be found that the rejection rate of the membranes treated with Cu + was largely improved (the rejection rates of Methyl Blue (MB), Congo Red (CR) and Evans Blue (EB) were enhanced from 75 % to 93 %, 91 % to 99.99 % and 83 % to 99.99 %, respectively), while exerting a minimal effect on the water permeance. The present work provides a new strategy for the development and application of metal ion complexation in the modification of ultrafiltration (UF) membranes.