Pervaporation separation of chlorinated environmental pollutants from aqueous solutions by castor oil based composite interpenetrating network membranes

Castor oil derived polyurethane (PU)-polydimethylsiloxane (PDMS) blends were synthesized to develop novel composite interpenetrating network (CIPN) membranes for improving the efficiency of pervaporation (PV) in selective removal of toxic chlorinated volatile organic compounds (VOCs) such as dichloromethane (DCM), 1,2-dichloroethane (DCE), 1,1,2-trichloroethane (TCE), and 1,1,2,2-tetrachloroethane (TeCE) from dilute aqueous solutions. Structural characterization of the synthesized CIPN membranes was performed by several analytical methods to evaluate thermal stability, swelling characteristics, extent of cross-linking, crystallinity, surface morphology and mechanical strength. Among the CIPNs of varying compositions, the membrane comprising of 8 wt% PDMS in PU exhibited moderate steady state flux values of 0.183, 0.162, 0.060 and 0.082 kgm(-2) h(-1) associated with correspondingly high selectivity values of 672, 1415, 10,901 and 19,407 for different feeds containing w/v % concentrations of 1.33% DCM, 0.84% DCE, 0.44% TCE and 0.28% TeCE in water, respectively. The experimental results have demonstrated that the triglyceride derived PU IPNs have influenced the desirable structural properties along with enhancement in perm-selectivity. The development of high-performance CIPN membranes for PV will certainly stand as a preliminary breakthrough for VOCs removal from aqueous media efficiently.