Preparation And Modification On Desulfurization Performance Study Of PDMS Membrane

The organic sulfurs from fluid catalytic cracking gasoline(FCC gasoline),which take up to 75%of total sulfur in China's motor gasoline.The combustion of sulfur in the motor gasoline can produce toxic SOx compounds which cause serious environment pollutions.Therefore,it is very important to reduce the sulfur content from FCC gasoline.Pervaporation(PV),as a new separation technology,has been widely used in gasoline desulfurization due to its high efficiency,less energy consumption and environmentally friendly.The PV membrane plays the most important role in PV desulfurization.Polydimethylsiloxane(PDMS),as one of the typical membrane,has been widely applied in gasoline desulfurization.In this article,the desulfurization performance of PDMS/PVDF composite membranes were studied systematically with three different cross-linking agents firstly and then improved by the CPO-27-Ni metal organic framework(MOF)incorporated into PDMS matrix.The PDMS/PVDF composite membranes were prepared by curing PDMS with three different cross-linking agents.They were 3-Aminopropyltrimethoxylsilane(APTMS),3-Glycidyloxypropyltrimethoxylsilane(GPTMS)and 3-Mercaptopropyltrimethoxylsilane(MPTMS),respectively-These PDMS/PVDF composite membranes were characterized by Fourier Transform infrared spectroscopy(FTIR-ATR),X-ray photoelectron spectroscopy(XPS),Scanning electron microscopy(SEM),and then evaluated by static tensile test,swelling degree test and surface detach experiment.The results showed that A-PDMS membrane had highest cross-linking density,best anti-swelling ability and excellent combination between the separation layer and support layer.Moreover,the effect of operation temperature and the feed sulfur content on separation performance were investigated systematically.Experimental results indicated that PDMS membrane crosslinked with APTMS presented the highest enrichment factor with 3.46 at 45 ?,and PDMS membrane crosslinked with MPTMS presented the highest permeation flux with 21.19 kg/m2 h at 45 ?.Then,the MOF/PDMS mixed matrix membranes(MMMs)were prepared for pervaporation desulfurization with the APTMS cross-linking agent.SEM,X-ray diffraction(XRD)and nitrogen adsorption were used to study the structure of CPO-27-Ni particles.The structural morphology,thermal properties,crystallinity and swelling behavior of all PDMS MMMs were systematically investigated by SEM,thermo gravimetric analyzer(TGA),XRD and swelling test.The effect of CPO-27-Ni on pervaporation performance of membranes were evaluated by pervaporation experiment.Compare with pure PDMS membrane,both total flux and enrichment factor of the CPO-27-Ni/PDMS MMMs were increased remarkably.This phenomenon can be ascribed to the good compatibility between PDMS and CPO-27-Ni particles and thiophene-selective sorption of CPO-27-Ni.When the loading of CPO-27-Ni was 6%,the optimal pervaporation performance was achieved with a flux 5.92 kg/(m2�h)and an enrichment factor of 4.05,which increased by 68.7%and 23.7%versus pristine PDMS membrane,respectively.