Sunflower oil-based liquid membrane processes for extraction of inorganic and organic compounds

Extraction of inorganic and organic compounds using liquid membrane-based extraction processes offers many advantages over conventional solvent extraction technology. The mechanism in this approach allows the "target" compound (inorganic or organic) to be selectively extracted from the source solution of multi-components into another liquid solution (defined as liquid membrane). This compound can then be recovered in the required phase thus providing the scope for selective recovery. This process when scaled-up using commercially available membrane modules such as hollow-fibre membrane contactors have demonstrated great potential with higher throughput and faster rate of recovery. In the literature the processes were studied with solvents from non-sustainable source; they have hazardous properties (toxic, corrosive and health and safety issues), and produce undesirable environmental impact. In recent years there have been research work to examine the feasibility of other solvents from sustainable source and with good characteristics to overcome or minimize some of the above adverse effects. One such system has been found effective is based on sunflower oil which is considered environmentally-friendly and has the potential to be used in large-scale application. Two parameters: the partition behavior and the overall mass transfer coefficient are important in designing such a process. The determination (or calculation) of these values have to be performed considering various characteristics of the system. The partition behavior are determined experimentally and the overall mass transfer coefficient can be calculated using correlations from the literature. In this chapter, a simplified equation is presented for the determination of overall mass transfer coefficient in the extraction of various compounds using sunflower oil-based liquid membranes in a bench-scale hollowfibre membrane contactor. The compounds considered in this chapter are: (i) extraction of an inorganic solute such as chromium ion (Cr(VI)) from polluted water sources and (ii) selective extraction of an antibiotic Shengjimycin (SJM) from its multicomponent mixture in aqueous media. The main attraction of the process is the success of sunflower oil-based extraction system, which is considered as a "green" solvent system with the benefit of being environmentally friendly, non-toxic, from sustainable source and it provides good selectivity.