Preparation and Characterization of Sulfonated Polymer/Non-Woven Composite Membrane for Biodiesel Production

摘要

A novel composite catalytic membrane as the heterogeneous acid catalyst for biodiesel production in flow-through catalytic membrane reactor (FTCMR) was prepared from sulfonated polyethersulfone (SPES) and polyethersulfone (PES) lined or inner supported with non-woven fabrics (NWF) by the phase inversion method. The effects of different solvents of the solution, coagulation bath and polymer concentration on membrane morphologies were investigated. Membrane structure was characterized by Field Emission scanning electron microscope (FESEM) and pore size distribution and porosity were measured by Micromeritics. FESEM pictures showed SPES/PES wrapped on the fibers of the NWF to form sponge-like structure with very high porosity under the optimum preparation condition of the catalytic membrane of 10 wt% concentration of SPES/PES solution, NMP as the solvent and ethanol as the coagulation. The catalytic membranes with different porosities were obtained by control of ethanol concentration in ethanol/acetone coagulation bath. The conversion obtained increased from 25.2% to 58.8% with an increase in the porosities of membranes from 32% to 68% at the residence time of 32 s. The membrane performance showed that the conversion reached 98.1% with the acid amount of 15.80 mmol (H+) at the residence time of 162 s in the FTCMR. In comparison, the reaction rate with the composite membrane as the catalyst is eight times higher than that with sulfuric acid under the same acid amount. The conversion was markedly increased from 58.8% to 98.2% with the increase of membrane layers from one to six. The catalytic membrane show very high conversion and excellent catalytic stability.