Preparation of thin-film nanocomposite membrane with alkali-treated nanozeolite to improve the dehydration performance of alcohol solution

Abstract

BackgroundThin-film nanocomposite (TFN) membrane separates water from alcohols effectively. However, during fabrication of TFN membrane, the dispersion of inorganic nanoparticle in the solvent media limits its used. MethodsNanozeolite, a natural inorganic particle, was modified through alkaline treatment using NaOH or NaHCO3. Both alkaline indeed improved the dispersion of nanozeolite in trimesoyl chloride (TMC)/n-hexane solution. TFN membrane had been prepared through interfacial polymerization of diethylenetriamine (DETA) and TMC, forming a thin selective polyamide layer on top of hydrolyzed polyacrylonitrile (mPAN) support. Significant findingsThe pore size of the nanozeolite was also enlarged due to the etching by the alkaline. Nanozeolite modified with NaHCO3 was dispersed well in the membrane surface, thus increasing its membrane efficiency. At the optimum preparation condition, 0.2 wt% NZ-NaHCO3 treated using 1 M NaHCO3, the TFNNZ-NaHCO3 exhibited the highest flux of 1,869 g∙m2∙h−1 with 99% water concentration in permeate. Furthermore, the modified membrane had a stable performance for long-term, as well as at different operating temperature and alcohol concentration in the feed. Therefore, the right concentration and type of alkaline could improve the property of nanozeolite for preparing high pervaporation membrane.