11 - Metal-organic frameworks (MOFs) based membranes for water treatment applications

Abstract

Global environmental challenges, especially water scarcity due to the rapid development of industrialization and the ever-increasing world population, have become one of the most dangerous threats humankind is currently facing. Compared to the conventional separation technologies, membrane-based separations have gained considerable attention in water purification due to its excellent performance in the removal of contaminants in a low cost and environmentally friendly way. However, polymer-based membranes are still disadvantaged by several challenges such as low fouling resistance toward contaminants and microorganisms present in the polluted water, which eventually affects the membrane performance in terms of permeability and selectivity. Off-late, metal-organic frameworks (MOFs) are materials of extensive interests, because of their fascinating chemistry, for instance, intrinsic and highly designable porous characteristics, high surface area, abundant adsorption functionalities (sites), etc., These above advantages of MOFs are made their attraction in wide range of industrial scale applications, including membrane-based water treatment processes. In this chapter, we plan to examine the usage of MOFs for the membrane-based water treatment, a relatively narrow yet ever more important part of MOFs application. We explored the role of MOFs in the enhancement of porosity and interconnectivity of water treatment membranes which has been reported by worldwide researchers as a potential pathway for effective water purification. Further, the applications of MOFs when incorporated into various membrane-based water treatment processes such as forward osmosis (FO), reverse osmosis (RO), membrane distillation (MD), nanofiltration (NF) and ultrafiltration (UF) using different experimental techniques have been discussed. In conclusion, some future prospects and challenges to be faced and measures that need to be taken into consideration for wide range applicability of MOFs to remove the contaminants effectively from aqueous environments have been discussed.