Responsive Polymeric Materials: Advances in Membrane-based Technologies for Water Treatment Processes

Abstract

Owing to their tunable separation selectivity, membrane-based technologies are considered state-of-the-art for water treatment processes. Although these technologies have found practical applications, most are chemical or energy intensive. Thus, there is increasing effort to develop new materials that minimize the chemical and energetic input while extending the membrane lifespan and enhancing its performance. In this context, using responsive materials arises as a feasible alternative. Responsive materials adapt their physicochemical properties in response to changes in the surrounding environment. Responsive polymeric membranes have been developed to respond to changes in pH, temperature, ionic strength, and moisture. Catalytic membranes, another type of responsive membrane, employ catalytic routes to selectively degrade/convert a specific kind of foulant. Amongst all the possibilities, electro-, photo-, and biocatalytic membranes have been proposed where catalysis occurs once the membrane is in contact with the target molecule or exposed to an external stimulus. This chapter addresses recent advances in the development of responsive polymeric membranes for water treatment applications. The discussion is complemented with a summary of recent designs, proposed mechanisms, operating principles, and critical advantages and disadvantages of different responsive materials used for membrane-based technologies. Finally, the challenges and future directions in the field are discussed.