PDMS/PEI复合膜对FCC汽油的脱硫性能(Ⅲ)Ag_2O载体促进传递

Pervaporation performance of polydimethylsiloxane/polyetherimide composite membrane for separation of thiophene/heptane mixture(Ⅱ) Facilitated transport by Ag_2O

以聚醚酰亚胺(PEI)超滤膜为支撑层,聚二甲基硅氧烷(PDMS)为复合层,制备PDMS/PEI渗透汽化催化裂化(FCC)汽油脱硫复合膜.实验选择Ag2O作为促进添加剂,利用可逆化学作用强化物质在膜内的传递过程,使膜分离兼具高通量和高选择性的特点,突破Robeson上限的限制,解决通量和选择性两者的矛盾.通过傅立叶红外光谱仪(FTIR-ATR)对PDMS/PEI复合膜表面进行结构分析,对比Ag2O填充前后官能团的变化.通过扫描电子显微镜(SEM)分析复合膜表面的形态.考察了添加剂的填充比例及料液温度等对渗透汽化脱硫性能的影响,讨论了固定载体促进传递的机理.

Crosslinked PDMS/PEI composite membranes were prepared for gasoline sweetening by using PEI UF membrane as the mieroporous supporting layer and PDMS as the composite membrane. Ag2O powder was taken as the fillers for preparation of the fixed - site carrier PDMS membranes, in which the facilitated transport of thiophenes was expected. Membrane process enhanced by reversible chemical reaction offers possibilities of high mass transfer rates and selective separation, which can break the limitation of Robeson, especially at low partial pressures of permeant species. The compositions of the PDMS/PEI composite membrane were characterized by reflection FTIR. The morphologies of the surface and cross - section of PDMS/PEI composite membrarte were investigated by scanning electron microscope （SEM）. The pervaporation performances of the PDMS/PEI composite membranes for the separation of thiophene/heptane mixtures were studied. The effects of Ag2O concentration and feed temperature on the separation efficiency of n - heptane/thiophene mixtures were investigated experimentally, and the swelling degree of the composite membranes was also studied. In addition, the facilitat- ed transport mechanism and the models of facilitated transport process were discussed.