Facile Preparation of a Laponite/PVA Mixed Matrix Membrane for Efficient and Sustainable Pervaporative Dehydration of C1-C3 Alcohols.

Abstract

The exfoliation method was applied for the preparation of high-water selective mixed matrix membranes (MMMs), especially for the dehydration of C1–C3 alcohol–water solutions. Herein, a facile and easy method was employed to fabricate physically cross-linked Laponite nanosilicate clay–PVA MMMs without additional cross-linking by a one-step synthesis route for water dehydration from methanol, ethanol, and isopropanol aqueous solutions. The morphologies, chemical structures, thermal stabilities, and surface hydrophilicity of Laponite–PVA MMMs were investigated properly by different characterization techniques. The Laponite concentration has affected the fractional free volume of the membranes, as proven by positron annihilation lifetime spectroscopy analysis. The MMMs displayed both a significant improvement in the separation factor and remarkable enhancement in the permeation fluxes for the three alcohol systems. The influence of the operating temperature on the MMM performance was investigated for the methanol/water solution. The methanol permeability was 100-fold lower than that of the water, indicating that the membranes are more water selective. Particularly, the Laponite–PVA membrane with 5 mg/mL Laponite loading exhibits excellent separation efficiency for C1–C3 dehydration having water permeabilities higher than most other polymeric membranes from the other literature studies of 2.82, 2.08, and 1.56 mg m–1 h–1 kPa–1 for methanol, ethanol, and isopropanol/water systems, respectively. This membrane development allows a more efficient and sustainable separation of aqueous alcoholic mixtures.