Repairing of graphene oxide membranes based on SPEEK substrate for organic solvents nanofiltration through PEI needle thread method

Owing to the increasing need to mitigate excessive organic solvents waste, the efficient separation and purification of organic solvents have attracted more attention. Carbon nanomaterials have attracted great attention in separation and purification technology. However, fabrication of GO-based organic solvents nanofiltration (OSN) membranes with stable and high effective separation performance is still a challenge due to their tendency to swell and inevitable GO interlaminar defects. In this work, we presented stable and crosslinked GO membranes based on (sulfonated polyether ether ketone) SPEEK substrate via polyethyleneimine (PEI) repairing for the first time. Specifically, the hydrogen bonds between the SPEEK substrate and GO eliminated interface incompatibility. The mitigation of microporous defects via PEI endowed the membranes with good permselectivity. A facile glutaraldehyde (GA) crosslinking restricted the expansion of the GO layer to promise high selectivity and long-term stability in organic solvents. The elemental analysis and Nano IR were used to evaluate the appearance of PEI among the GO interlayer. The resulting membranes exhibited ultrahigh flux for pure solvents (30, 27.16, 13.88, 9.94, 7.42 L m−2h−1bar−1 for water, acetone, methanol, ethanol, and IPA) and good dyes molecular separation performance (over 99%). Meanwhile, the membranes could highly separate mixed dyes with different molecular weights. Most importantly, long-term filtration operation and ultrasonic processing further proved the stability of the membranes. Our technique opens opportunities for fabricating stable and high effective membranes with carbon nanomaterials in organic solvents.