GAS PERMEATION PARAMETERS OF MIXED MATRIX MEMBRANES BASED ON COMPOSITE FILLER PANI/UIO-66 IN PEBAX POLYMER

Abstract

Nowadays global warming is a significant concern for the human being. Efforts have been done worldwide to develop technologies for the reduction of CO2 from atmosphere. For gas separation, mixed matrix membranes (MMMs) have received great attention which are prepared from different inorganic fillers and polymers. In this work, MMMs were prepared through solution casting method in which Uio-66 and PANI@Uio-66 were incorporated into poly (ether-block-amide) PEBAX matrix. . Good polymer-filler interaction and filler dispersion were observed by X-ray diffraction (XRD), glass transition temperature (Tg) measurement, activation energies and thermogravimetric analysis (TGA). An X-Ray diffraction (XRD) spectrum of UiO-66 shows two high peaks at position (2θ) 7° and 9° but these two peaks have been disappeared in the composite of PANI@UiO-66 which shows that crystallanity has been decreased due to polymerization of polyaniline into UiO-66. Successful doping of polyaniline (PANI) was confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Scanning electron microscope (SEM) results showed that all membranes have smooth structure. The gas separation results of Uio-66/PEBAX showed that all CO2 permeabilities increased as compared to the pure PEBAX membrane. Generally incorporation of UiO-66 increased the diffusion of the molecules of the gas because of the creation of large pores in the membrane which provide easy way for the penetrant gases. The ideal selectivity of Uio-66/PEBAX based MMMs decreased for CO2/CH4 and CO2/N2 as compared to unfilled membrane. CO2 permeability up to 30 wt% loading increased by 193% and 180% and ideal selectivity was decreased by 70.6% and 76.9%, respectively for CO2/CH4 and CO2/N2 gas mixtures in comparison to unfilled PEBAX membrane. The selectivity is increased by incorporating the PANI@Uio-66 in PEBAX matrix because of the amine group present in polyaniline. The permeability of PANI@Uio-66/PEBAX based MMMs is decreased as compared to Uio-66/PEBAX based MMMs. CO2 permeability up to 30 wt% loading increased by 147.2% and 151.2% combined with increased selectivity by 130.2% and 111%, respectively for CO2/CH4 and CO2/N2 gas mixtures in comparison to unfilled PEBAX membrane. The increase in selectivity is due to amine group present in polynailine.