Wenying Shi

Biodiesel production from soybean oil by quaternized polysulfone alkali-catalyzed membrane.

A series of alkalized polysulfones (APSF) were synthesized by several chemical reactions (chloromethylation, quaternization and alkalization). Among these reactions, chloromethylation and quaternization are two key reactions and have been studied in detail regarding the optimization of both chloromethylation and quaternization. FTIR and (1)H NMR spectrum confirmed the successful preparation of chloromethylated polysulfone. The best IEC of APSF was obtained for 1.68meqg(-1) under reaction time of 10h and reaction temperature of 45°C. The APSF membrane as a heterogeneous catalyst for the transesterification of soybean oil with methanol was prepared through the method of solvent evaporation phase inversion. The effects of co-solvent types, mass ratios of soybean oil/co-solvent, water content and free fatty acids (FFAs) content in soybean oil on the conversions using the APSF membrane during transesterification were studied. The reusability of the APSF membrane and the kinetics of the reaction catalyzed by the APSF membrane were also investigated.

Effects of zinc oxide Nanospheres on the Separation performance of Hollow fiber poly(piperazine-amide) composite nanofiltration membranes

The inner-skinned hollow fiber composite (HFC) nanofiltration (NF) membranes were modified through the incorporation of zinc oxide nanospheres in the poly(piperazine amide) layer during the interfacial polymerization (IP) process. The active layer was coated on the inner surface of polysulfone (PSF) support membrane via Two-way coating technique. The chemical composition and morphology of HFC membrane surface were evaluated through the Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and Scanning Electronic Microscopy (SEM). The effects of zinc oxide (ZnO) nanospheres on membrane performance including the hydrophilicity, separation performance and chlorine resistance were investigated. The results showed that the modified HFC membranes with low concentration ZnO nanospheres (1.5 wt%) had an improved flux (33.8 L·m-2·h-1) meanwhile the salt rejection of MgSO4 was well maintained (92.2 %) at 0.7 MPa. The introduction of ZnO also dramatically enhanced the chloride resistance of composite NF membranes in comparison with the control membranes prepared without ZnO. Therefore, nano metallic oxide like ZnO could be considered as a potential modifier to improve the performance of HFC nanofiltration membranes.

Preparation and characterization of inner-pressure hollow fiber composite membrane via two-way coating technique for CO2/CH4 separation

High-selectivity inner-pressure hollow fiber composite (HFC) membrane for CO2/CH4 separation was prepared through the Two-way coating (TWC) technique. The blends of poly(vinylamine) (PVAm)/polyvinyl alcohol (PVA) were coated onto porous hollow fiber polysulfone (PSF) ultrafiltration (UF) membrane with an effective membrane area of 0.4 m2. The effects of fabrication parameters on the permselectivity of the resultant HFC membrane were investigated and the optimum preparation conditions were obtained as follows: coating time for 30 min and air blowing time for 30 min after the coating. The prepared HFC membrane showed the typical characteristic of fixed carrier membrane with a high selectivity of CO2 and CH4: the separation factor of CO2/CH4 (40 vol% CO2 at 25 °C and 0.2 MPa) was 36.6 and the CO2 permeability was 56.3 GPU. Field emission scanning electron microscopy (FESEM) images indicated that the HFC membrane prepared by TWC technique had a uniform coating layer along the whole hollow fiber. Membrane permselectivity showed almost no difference between different membrane sections. The HFC membrane showed a good stability during the continuous testing process of 540 h. And the HFC membrane preserved at 30 °C and 40 % humidity exhibited a good durability with a basically unchanged separation factor after 30 days.