title: Enhanced pervaporative desulfurization by polydimethylsiloxane membranes embedded with silver/silica core-shell microspheres.
abstract: Pervaporative desulfurization based on membrane technology provides a promising alternative for removal of sulfur substances (as represented by thiophene) in fluid catalytic cracking (FCC) gasoline. The present study focused on the performance enhancement of polydimethylsiloxane (PDMS) membrane by incorporation of core-shell structured silver/silica microspheres. A silane coupling agent, N-[3-(trimethoxysily)propyl]-ethylenediamine (TSD), was used to chelate the Ag(+) via its amino groups and attach the silver seeds onto the silica surface via condensation of its methoxyl groups. The resultant microspheres were characterized by Zeta-positron annihilation lifetime spectroscopy (ZetaPALS), inductively coupled plasmaoptical emission spectrophotometer (ICP), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Ag(+)/SiO(2)-PDMS composite membranes were prepared by blending PDMS with the as-synthesized silver/silica microspheres. PALS analysis was used to correlate the apparent fractional free volume with permeation flux. The sorption selectivity towards thiophene was enhanced after incorporation of silver/silica microspheres due to the π-complexation between the silver on the microsphere surface and the thiophene molecules. The pervaporative desulfurization performance of the composite membrane was investigated using thiophene/n-octane mixture as a model gasoline. The composite membrane exhibited an optimum desulfurization performance with a permeation flux of 7.76 kg/(m(2)h) and an enrichment factor of 4.3 at the doping content of 5%.
authors.affiliation: Key Laboratory for Green Chemical Technology, Ministry of Education of China, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
authors.forename: Ruijian
authors.initials: R
authors.lastname: Cao
authors.forename: Xiongfei
authors.initials: X
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Wu
authors.forename: Jingtao
authors.initials: J
authors.lastname: Wang
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Liu
authors.forename: Zhongyi
authors.initials: Z
authors.lastname: Jiang
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D008567:Membranes, Artificial; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D004129:Dimethylpolysiloxanes; D008567:Membranes, Artificial; D012834:Silver; C013830:baysilon; D013455:Sulfur; D012822:Silicon Dioxide