Pervaporation separation of thiophene/heptane mixtures with polydimethylsiloxane membrane

摘要

Crosslinked PDMS/PEI composite membranes were prepared, in which asymmetric microporous PEI membrane prepared with phase inversion method was acted as the microporous supporting layer in the flat-plate composite membrane. The different function composition of the PDMS/PEI composite membranes were characterized by reflection FTIR. The surface and section of PDMS/PEI composite membranes were investigated by scanning electron microscope (SEM). The elements of the composite membranes were determined by XPS analyses. The composite membranes prepared in this work were employed in pervaporation separation of n-heptane/thiophene mixtures. Effect of amount of PDMS, crosslinking temperature, amount of crosslinking agent and crosslinking time, on the separation efficiency of n-heptane/thiophene mixtures was investigated experimentally. Experiment results demonstrated that 80-100 ?? Of crosslinking temperature was more preferable for practical application, as the amount of crosslinking agent was up to 20wt%, and 25wt% of PDMS amount was more optimal as far as flux and sulfur enrichment factor were concerned. In addition, the swelling degree of and stableness of composite membrane during long time operation were studied, which should be significant for practical application.