Octyl silane modified nano alumina-polydimethylsiloxane composite membrane for pervaporative desulfurization of model gasoline

Polydimethylsiloxane (PDMS)-octyl silane modified nano alumina composite membrane was prepared over polyether sulfone (PES) support by varying alumina percentages for pervaporative desulfurisation of model fuel, isooctane with thiophene. Prepared membranes were characterized by FESEM, TEM, XRD, TGA, XPS, contact angle, and tensile strength analysis. The swelling resistance of membranes was verified by the swelling test in model fuel. Desulfurization results were obtained at different initial sulfur (in the form of thiophene) concentrations of 500–2500 ppm in model fuel, temperatures of 30–70 °C, and changing feed flow rates of 8.14–26.22 l/h. The change in total permeate flux (J) and enrichment factor (η) under the varying parameters is discussed. Activation energies of permeation for thiophene and isooctane are reported. The highest η value of 7.32 at 30 °C and the highest J value of 0.051 kg/m2h at 70 °C were obtained using PDMS (1.5) membrane. Temperature is found to have a reverse effect on the enrichment factor, whereas the increase in temperature favors the total flux. As observed from TGA, the prepared PDMS membranes show high thermal stability (stable under 370 °C in N2 environment). Long-term stability performance test proves high stability of the prepared composite membrane in terms of flux and enrichment factor. [Display omitted] •Pervaporative desulfurisation was done using PDMS−silane modified alumina membrane.•Crosslinker APTMS was optimized to increase membrane stability in model fuel.•Modified alumina NPs increase the alumina compatibility with PDMS membrane matrix.•Enrichment factor obtained using PDMS (1.5) is 7.32 at 30 °C.•PDMS−alumina membranes were stable up to 3000 ppm sulfur concentration and 370 °C.