Poly[bis(p -methyl phenyl) phosphazene] pervaporative membranes for separating organosulfur compounds from n -heptane and its surface functionalization

This work investigates the application of poly[bis(p-methyl phenyl) phosphazene] (PMePP) for separating organosulfur compounds from n-heptane. PMePP was synthesized and characterized by NMR, X-ray photo spectroscopy, thermogravimetric analysis, scanning electron microscopy, and Fourier transformed infrared spectroscopy. Membranes based on PMePP were fabricated and investigated for desulfurization of FCC (fluid catalytic cracking) model gasoline by pervaporation. The effects of operating temperature, feed composition, and feed sulfur content on the performance of PMePP membranes were investigated. The experimental results showed that the PMePP-based membranes are effective for FCC gasoline pervaporative desulfurization. To provide active spots for future grafting modification, the surface functionalization of PMePP was carried out to convert the methyl units into carboxylic units. The surface-functionalized membrane was also investigated for its pervaporation performance, and results showed the increased in enrichment factor and less temperature dependence.