Separation of toluene–methanol mixtures by pervaporation using filled elastomeric membranes

• Hybrid type membranes were made by incorporating filler in natural rubbers.
• Carbon black, clay and zeolite were used as filler.
• The membranes were crosslinked with sulfur and accelerator.
• The membranes were used for pervaporative separation of toluene–methanol mixtures.
• These membranes showed high flux and toluene selectivity.

Hybrid type elastomeric membranes were prepared by mixing natural rubber (NR) with 10 wt% of (of rubber) three different types of organophilic fillers, i.e., carbon black, organophilic clay and organophilic zeolite. These elastomeric membranes were cured (crosslinked) by semi efficient vulcanization technique using sulfur (S) and zinc diethyl dithio carbamate (ZDC), an ultra fast room temperature curing accelerator to obtain three membranes designated as NRCB, NRC and NRZ, respectively. The membranes were characterized by crosslink density, FT-IR, SEM analysis, and mechanical properties and used for pervaporative removal of low concentration of toluene from its mixtures with methanol at different feed toluene concentrations and temperatures. The NRCB membrane was found to show the best result with respect to toluene flux and selectivity over the entire feed concentration of 3–40 wt% of toluene in methanol.

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