Fabrication and testing of mixed matrix membranes of UiO-66-NH2 in cellulose acetate for CO2 separation from model biogas

Abstract

Mixed Matrix Membranes (MMMs) of UiO-66-NH2 nanoparticles dispersed in Cellulose Acetate (CA) were prepared with filler loading of 2–20 wt%. MMMs were tested for the upgradation of model biogas (60%–40%) mixture of CH4/CO2 at a feed pressure of 2 bar and 1.5 bar. Detailed characterization of MMMs was performed with Fourier transform infrared spectroscopy (FTIR), Thermo-gravimetric analysis (TGA), Differential scanning calorimetry (DSC), and Field emission scanning electron microscopy (FESEM) to investigate the physical and thermal properties. MMMs formed are defects-free, voids-free, and without polymer rigidification, indicating a better filler polymer interface. MMMs showed improved CO2 permeability while retaining the CO2/CH4 selectivity. The 10 wt.% UiO-66-NH2/CA MMM showed optimum gas separation performance with CO2 permeability of 11 Barrer and CO2/CH4 selectivity of 10. The UiO-66-NH2/CA MMMs performed better when compared to the pure CA membrane. The experimental permeability and selectivity data were compared with the predicted data using Maxwell, Lewis–Nielsen, Higuchi, and Bruggeman's model.