Metal-organic framework/poly(vinyl alcohol) nanohybrid membrane for the pervaporation of toluene/n-heptane mixtures

As a new type of filler for nanohybrid membranes, metal organic frameworks (MOFs) have attracted intense interest in recent years. In this work, MOF-based Cu-3(BTC)(2)/PVA (BTC=benzene-1,3,5-tricarboxylate, PVA=poly(vinyl alcohol)) nanohybrid membranes were fabricated on a ceramic tubular substrate by using a pressure-driven assembly method. The morphology and structure of the resulting membranes were characterized by scanning electron microscope, energy dispersive X-ray spectrometer, and powder Xray diffraction. The Cu3(BTC)2/PVA membranes were then used in separating 50 wt% toluene/n-heptane mixtures through pervaporation. The effects of PVA concentration, Cu-3(BTC)(2) loading, teed composition, and operating temperature on membrane performances were explored. The results indicate that, compared with pristine PVA membrane, the separation factor and permeate flux of optimized Cu-3(BTC)(2)/PVA membranes are improved from 8.9 and 14 g/(m(2) h) to 17.9 and 133 g/(m(2) h), respectively. A speculation of the transport process of permeating components in the selective layer of Cu-3(BTC)(2)/PVA membrane was proposed. Enhanced affinity between toluene and the membrane through incorporating Cu-3(BTC)(2) particles plays a key role in improving separation performances. (C) 2015 Elsevier BM. All rights reserved.