Novel TFC membrane with crosslinked PMIA active layer fabricated by the T-FLO technique for dye desalination

Abstract

Poly (m-phenyleneisophthalamide) (PMIA) is a promising candidate for membrane material resulting from its excellent thermal and chemical stability. Being the linear molecular structure, almost all studies have been carried out on PMIA as a substrate material for thin-film composite (TFC) membranes rather than an active layer. Here, amino-epoxide crosslinkers were introduced into the PMIA dope solution to modify the molecular structure for the first time. Employing the casting coupled solvent evaporation deposited the crosslinked PMIA (CPMIA) thin-film. The effect of crosslinker type and concentration on the morphology and the ion permeance have been investigated systematically. That is, achieving the separate optimization of the active layer. Based on the CPMIA thin-film with the best ion permeation, novel TFC membranes (TFC-CPE) with CPMIA active layer were generated successfully via the thin-film liftoff (T-FLO) technique for the first time. Results demonstrated that TFC-CPE had desirable dye desalination performance. For feeding solution containing 100 ppm CR and 1 g L−1 NaCl, the permeance was 25.17 L m−2 h−1 bar−1. CR rejection was 99.88% and NaCl rejection was 6.30%. The selective coefficient α was up to 793.9. It also demonstrated that the TFC-CPE had excellent thermal resistance, anti-fouling capability and long-term stability. In conclusion, the novel TFC membrane has a promising future for in-situ dye wastewater treatment. This work throws light on the PMIA modification and the preparation of the TFC membrane with a novel active layer.