A novel poly(dimethyl siloxane)/poly(oligosilsesquioxanes) composite membrane for pervaporation desulfurization

Pervaporation performance of novel poly(dimethyl siloxane) (PDMS)/poly(oligosilsesquioxanes) (POSS) composites was analyzed by measuring solubility and diffusion behavior of a series of solvents in the composites using inverse gas chromatography (IGC) fitted with a packed column. The solubility and diffusion coefficients of thiophene, benzene and toluene at infinite dilution in the composites are greater than the other four solvents (cyclohexane, n-pentane, n-hexane and n-heptane). The PDMS/POSS composite membranes were thus prepared and characterized using scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. The pervaporation separation performance of the composite membranes was evaluated and agreed with the IGC study. The composite membranes are found to have a great promising application in pervaporation separation of thiophene from n-heptane.

Research highlights▶ Novel poly(dimethyl siloxane) (PDMS)/poly(oligosilsesquioxanes) membranes are prepared and evaluated. ▶ Sorption and diffusion behavior of thiophene, benzene, toluene, cyclohexane, n-pentane, n-hexane and n-heptane in the membranes are investigated by IGC. ▶ The additive of poly(oligosilsesquioxanes) into PDMS enhances the solubility coefficient and diffusion coefficient of thiophene, benzene and toluene in the PDMS. ▶ The as-prepared membranes exhibit the best pervaporation performance in separation of thiophene/n-heptane, benzene/n-heptane and toluene/n-heptane.