Principles of Membrane Surface Modification for Water Applications

Membrane technologies offer efficient and reliable solutions to separate components from aqueous media. Among them, pressure driven membrane separation processes namely microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) have been preferred in many industrial operations (food, pharmaceutical, chemical, drinking water, wastewater) due to the intrinsic advantages such as high selectivity, stability, ecocompatibility, scalability, flexibility, small footprint and low operational cost. This chapter will focus on the latest developments of surface modified polymeric membranes via the Layer-by-layer self-assembly approach and incorporation/decoration of nanomaterials. Variable parameters including size and charge of polyelectrolyte, ionic strength of the media, number of bilayers, and different types of nanomaterials on the bulk and surface property, water permeability, selectivity, antifouling, antibacterial, and adsorptive properties of the resultant composite membranes will be reviewed by comparison with the neat membranes. Membrane stability in terms of throughput and rejection characteristics during long-term filtrations will be addressed in this chapter.