Enhanced performance polyamide membrane by introducing high-porosity SOD/GO composite interlayer to tailor the interfacial polymerization process

Abstract

Controllable preparation of high-performance polyamide nanofiltration (NF) membranes that can be used in various applications such as seawater desalination and wastewater treatment is very promising. In this work, a high-performance polyamide NF membrane was designed using high-porosity hydroxy sodalite/graphene oxide (SOD/GO) composite interlayer to slow down the diffusion of amine monomer and control the interfacial polymerization (IP) process. The unique tortuous effect and hydrogen bonds with amine monomers caused by the dense interlayer significantly inhibit the diffusion of amine monomers (reduction of 50 % in diffusion rate), thereby resulting in the controllable slow IP process. The slowing IP process facilitates the formation of thinner dense polyamide (PA) layer with stripe morphology and narrow pore size. Consequently, the optimal polyamide membrane with composite interlayer possesses a superior water permeability of 22.05 L m-2h−1⋅bar−1, nearly 2.5 fold that of the controlled one, while retaining an excellent rejection of Na2SO4 (97.25 ± 0.81 %). Moreover, the polyamide membrane depicts outstanding antifouling propensity (flux-recovery ratio (FRR) = 82 %), long-term stability (80 h) and pressure resistance (9 bar). This work provides a novel strategy for controllable construction of high-performance NF membrane and deepens the slights into the interlayer influences IP process.