In-situ assembled amino-quinone network of nanofiltration membrane for simultaneously enhanced trace organic contaminants separation and antifouling properties

Abstract

Nanofiltration has attracted extensive attention in surface water purification and wastewater reclamation with its high permeance and effective interception of dissolved organic matter. However, the poor removal of trace organic contaminants and membrane fouling still limit its application, resulting in the potential health risk and excess energy consumption, respectively. Herein, an amine-quinone networks (AQN) coating coordinated by the 5-hydroxy-1,4-naphthoquinone (HNQ) and polyethyleneimine (PEI) was simply and facilely assembled on a commercial nanofiltration membrane. The optimum modified membrane conferred a significant increase in the rejection of trace organic contaminants (e.g., over 99% for ofloxacin). Simultaneously, the permeance of the modified membrane exhibited a slight enhancement (10%) over that of the pristine membrane thanks to the greater hydrophilicity of AQN coating without blocking pores of the polyamide layer. Static adsorption of BSA indicated that the NF-AQN membrane had excellent fouling resistance against proteins. In addition, after several cycles of dynamic fouling experiment, the higher flux recovery after physical cleaning and lower flux decline during filtration further demonstrated the outstanding antifouling property of the modified membrane. This study presents a low-cost, facile and scalable method using AQN coating for improving the performance of existing commercial nanofiltration membranes and alleviating their fouling in operation.