Inorganic Particles Filled Polyether Block Amide (Pebax) Membrane And Enrichment Of Thiophene Via Pervaporation

In recent years, the development of effective and economic motor gasoline desulfurization method is increasingly valued. This research according to solubility parameter theory, polyether block amide(PEBAX2533) was chosen as a pervaporation membrane material for removal of thiophene from model gasoline system composed of thionphene and n-heptane. Bentonite was modified by Hexadecyl trimethyl ammonium bromide (CTAB) and HZSM-5zeolite with higher silicon aluminum as a filling materials, filled membrane and composite membrane were prepared, respectively. The structure and crystalline nature of filled membrane were characterized by FTIR、XRD and SEM, respectively. XRD and FTIR show that the CTAB-modified bentonite is only physically blended with the polymer matrix without chemical interactions. It can be observed that the membrane is dense with no appreciable voids and dispersed uniformly in the PEBAX matrix. In addition, separation layer and supporting layer combaine together tight from the images of SEM. Through the swelling experiment in thiophene and n-heptane mixtures, it can be found that membrane has a good adsorption capacity for thiophene, the swelling degree of membrane is associated with filling amount of the particle, with CTAB-modified bentonite and HZSM-5zeolite content in the membranes increase to20%and10%respectively, the swelling of degree was reached maximum; the swelling degree also increased with the increasing of thiophene concentration and operation temperature. Investigation of the membrane separation performance by pervaporation experiments, the results showed that the total permeation flux increased and enrichment factor decreased with the increasing of operation temperature and the concentration of thiophene. Under the thiophene concentration1100μg·g-1and at30℃, both CTAB modified bentonite filled PEBAX filled membrane and composite membrane, with the bentonite20wt%, their separation performance were best, the total flux were2.93kg·m-2·h-1and2.81kg·m-2·h-1respectively, and the corresponding enrichment factor of thiophene were3.75and4.65; the membrane with HZSM-5zeolite10wt%, the pervaporation performance has best, total permeation flux and enrichment factor of thiophene1.58kg·m-2·h-1and4.25in the composited membrane with different HZSM-5zeolite contents.According to the above experiments of pervaporation for removal of thiophene from model gasoline with filled and filled-composited membranes, the results show that both the filled and filled-composited membranes have good separation performances for thiophene; the pervaporation performance of modified bentonite filled-composited membrane was better than that of HZSM-5zeolite filled-composited membrane; and the filled-composited membrane enrichment factor of thiophene is superior to filled membrane.