Pervaporation of dichloromethane from multicomponent aqueous systems containing n-butanol and sodium chloride

In this paper, pervaporation (PV) of dichloromethane (DCM) from binary and multicomponent systems at different feed concentrations and temperatures using a commercial hydrophobic membrane CMX-GF-010-D (CELFA AG, Switzerland) is reported. Coupling effects are studied by permeating DCM/n-butanol/water ternary mixtures. The effect of sodium chloride on the process performance is also evaluated by PV of ternary DCM/sodium chloride/water and quaternary DCM/n-butanol/sodium chloride/water mixtures. PV performance was evaluated by permeate flux and enrichment factor. Further, permeance was calculated for pure water, DCM/water and DCM/n-butanol/water systems at 40 °C. Partial fluxes were promoted with temperature in all the systems studied. The activation energy values for the permeation of volatile organic compounds (VOCs) in all the systems studied were higher than that of water. The PV of ternary DCM/n-butanol/water mixtures indicated that there was no coupling effect between the VOCs. The membrane presented higher fluxes of water than of VOCs. Further, the membrane exhibited about three times higher permeation flux and enrichment factor towards n-butanol than to DCM at equal VOCs concentration. The addition of electrolyte did not influence the membrane performance, neither the Arrhenius behaviour and no salting phenomena were observed. The calculated overall permeances indicate a faster transport of water through the membrane than of VOCs. Further, the permeance towards the transport of n-butanol was smaller than of DCM.