Separation of sulfoether compounds in garlic oil by integrated membrane technologies

This study investigated an integrated process to separate sulfoether compoundsfrom garlic oil. The garlic oil was pretreated by vapor distillation and the oil–watermixture was treated with the combination of ceramic membrane microfiltration(MF) and poly(dimethylsiloxane)/poly(vinylidene fluoride) composite membranepervaporation (PV). The optimum operating conditions with respect to sulfoethercompounds’ re covery were determined to be 1.8% feed concentration, 30C and0.10 MPa for ceramic membrane MF; and 40C, 5 h, 0.24 MPa and 0.32 L/min forPV. It was found that the emulsified oil was effectively separated by ceramic MFmembranes, and the rejection rates of diallyl sulfide (DAS), diallyl disulfide(DADS) and diallyl trisulfide (DATS) were 91.11, 99.8 and 100%, respective ly. Inthe subsequent process, PV membrane was used to recover the dissolved oil. PVmembrane had a good enrichment effect on DAS and DADS in the penetrant per-meate fluid, with separation factors of 6.31 and 5.45, respectively. Compared w ithoil–water mixture by vapor distillation, the yield of garlic oil is 99.6%. This studyshowed that MF and PV processes were attractive technologies for the recovery ofgarlic sulfoether compounds as they yield good separation and operate under mildconditions.