ABSTRACT
The increasing environmental concern has enforced to suppress the discharge of industrial wastes into the environment across the world. There has been a nutritional interest and the need for an efficient and cost effective process either for removal of toxic species or for the selective extraction and recovery of valuable species. Solvent extraction technology came into existence in the late 1940s. With the ever-increasing needs of separation engineering and the continuing evolution of new extractants, solvent extraction technology developed rapidly and has played a pinnacle role in diversified engineering fields. In the last few decades, the compounding of solvent extraction with other processes has created a number of new separation processes, which are solvent tinctured resins, extraction chromatography, electrostatic extraction, supercritical extraction and membranebased extraction. These membrane-based separation techniques are emerging as promising avenue in economizing energy compared to formal and traditional separation processes like packed bed absorption, adsorption, distillation, cryogenic separation, etc. Membrane-based technology has incurred appreciable attention because of its low energy consumption, capability of integration with other processes, easy scaling up and adjustable characteristics of the membrane. Membrane separation processes, in general, differ based on size (viz., microfiltration, ultrafiltration, nanofiltration), affinity (viz., reverse osmosis, pervaporation, gas separation), charge (viz., dialysis, electrodialysis), and chemical nature (viz., carrier-mediated separation) of the separated particles (Mulder, 1991; Pinnau and Freeman, 1999). It also differs based on the membranes materials such as solid
15.1 Introduction .......................................................................................................................... 255 15.2 Transport Mechanism through LM ......................................................................................256
