Pervaporation Polyvinyl Alcohol Membranes Modified with Zr-Based Metal Organic Frameworks for Isopropanol Dehydration

Abstract

Metal-organic frameworks (MOFs) are perceptive modifiers for the creation of mixed matrix membranes to improve the pervaporation performance of polymeric membranes. In this study, novel membranes based on polyvinyl alcohol (PVA) modified with Zr-MOFs (MIL-140A, MIL-140A-AcOH, and MIL-140A-AcOH-EDTA) particles were developed for enhanced pervaporation dehydration of isopropanol. Two membrane types (substrateless–freestanding; and formed on polyacrylonitrile support-composite) were prepared. The additional cross-linking of membranes with glutaraldehyde was carried out to circumvent membrane stability in pervaporation dehydration of diluted solutions. The synthesized Zr-MOFs were characterized by scanning electron microscopy, X-ray powder diffraction analysis, and specific surface area measurement. The structure and physicochemical properties of the developed membranes were investigated by Fourier-transform infrared spectroscopy, scanning electron and atomic force microscopies, thermogravimetric analysis, swelling experiments, and contact angle measurements. The PVA and PVA/Zr-MOFs membranes were evaluated in pervaporation dehydration of isopropanol in a wide concentration range. It was found that the composite cross-linked PVA membrane with 10 wt% MIL-140A had optimal pervaporation performance in the isopropanol dehydration (12–100 wt% water) at 22 °C: 0.15–1.33 kg/(m2h) permeation flux, 99.9 wt% water in the permeate, and is promising for the use in the industrial dehydration of alcohols.