Antibacterial thin film nanocomposite reverse osmosis membrane by doping silver phosphate loaded graphene oxide quantum dots in polyamide layer

Abstract

The development of thin film nanocomposite (TFN) reverse osmosis (RO) membranes has promoted the membrane technology for desalination. Novel nanocomposites are urgently being explored to develop superior performance TFN RO membranes. Graphene oxide quantum dots (GOQD) is considered to be an ideal nanofiller for improving membrane permeability due to its rich hydrophilic groups, uniform dispersion and small nanosheet shape. As a silver ion (Ag+) compound, silver phosphate (AP) possesses higher bactericidal effect than silver particle in membrane application. Accordingly, we synthesized the multifunctional nanocomposite of AP loaded GOQD by a facile electrostatically driven method. Subsequently, GOQD/AP was embedded into the dense polyamide (PA) layer via interfacial polymerization reaction. The GOQD/AP incorporated TFN membrane possessed a high flux of 39.6 L·m−2·h−1 at 16 bar, which was 1.5-fold higher than that of the pristine TFC membrane. Meanwhile, the salt rejection was maintained at 98.4%. Noteworthy, the TFN-GOQD/AP membrane exhibited strong bactericidal property against E. coli with a sterilization rate of 99.9% and good stability as well as excellent antifouling performance during RO process. This work provides a feasible strategy to prepare high permselective and anti-bacterial TFN RO membranes for desalination and wastewater reclamation.