Polyamide Thin Film Nanocomposite Membranes with In-Situ Integration of Multiple Functional Nanoparticles for High Performance Reverse Osmosis

Abstract

Polyamide (PA) thin film nanocomposite (TFN) reverse osmosis (RO) membranes have been vigorously developed, which could be used in saline water desalination, wastewater treatment and chemicals separation and purification. Aiming at further improving the TFN RO membrane comprehensive performances, such as the perm-selectivity, stability and anti-fouling/-microbial properties remains a great challenge. Herein, we proposed a biomimetic nanoreactor redox strategy to in-situ integration of multiple functional nanoparticles, i.e., biomimetic nanoreactor particles (BNPs) and silver (Ag) nanoparticles into the PA matrix for simultaneously regulating the membrane interior micropores and optimizing the surface property. A much hydrophilic selective layer with interior transporting channel structure renders the resultant RO membrane PA-BNP-Ag with an enhanced water flux of ~64.2 L·m-2·h-1 (1.55 MPa, 25 °C) without sacrificing NaCl rejection (~98.1%). The BNPs induce Ag nanoparticles uniformly distributed within the PA matrix, which significantly improves the membrane anti-fouling/-bacterial property. The water flux recovery ratio of PAM-BNP-Ag was improved to be higher than 96% during several cycles filtration of saline solution containing bovine serum albumin foulants. More importantly, the membrane sterilization rate against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) achieves nearly 100%. This work provides a new strategy for the construction of advanced PA TFN membranes with both high perm-selectivity and anti-fouling/-microbial property in RO desalination.

Keywords: reverse osmosis membrane, in-situ integration, multiple functional nanoparticles, anti-fouling/-microbial, high perm-selectivity