Chemically functionalized polyamide thin film composite membranes: the art of chemistry

Abstract

Polyamide thin film composite membranes have been conventionally used for reverse osmosis (RO) and forward osmosis (FO) processes. Despite their high efficiency and reliability, the innovation in design is polyamide thin film composite membrane one of the most sought-after strategies to heighten the performances of the membranes in terms of flux, rejection and antifouling properties. Membrane surface modification and functionalization is imperative to control and fine-tune the surface properties, as well as to confer new functionalities such as hydrophilicity and surface charge to the membranes. Various chemical modification strategies, including direct grafting and surface initiated polymerization, have been attempted for the modifications of RO and FO desalination membranes. This article provides a comprehensive review on the state-of-the-art chemical functionalization of RO and FO desalination membranes. Based on the contemporary work, the modification routes and the effects of chemical modifications on the desalination performances are thoroughly discussed. This review aims to enlighten the readers with deeper understanding on the roles of chemistry in designing and customizing the surface properties of membranes. This article also intends to provide the directions for exploring chemical functionalization to resolve the underlying issues or further heightening the desalination performances of RO and FO.