Pbi/Clinoptilolite Mixed-Matrix Membranes For Binary (N-2/Ch4) And Ternary (Co2/N-2/Ch4) Mixed Gas Separation

In this work, polybenzimidazole (PBI)-based mixed matrix membranes (MMMs) with natural zeolite were prepared and their transport properties for binary (N-2/CH4) and ternary (CO2/N-2/CH4) mixed-gas separation were studied. The MMMs, were prepared with PBI as polymeric matrix and Mexican natural zeolite clinoptilolite enriched with cations of Ca2+ as filler. The thermal properties analysis of the PBI and MMMs studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicates that the MMMs membranes have Tg higher than 350 degrees C and decomposition temperatures above 600 degrees C compared with the pristine membranes. PBI membrane and MMMs were analyzed by X-Ray Diffraction (XRD) and the diffraction patterns showed the zeolite signals combine with the amorphous dome from the polymeric matrix. In addition, the perm-selectivity properties of the polymeric membranes and MMMs were tested with binary (N-2/CH4; 10/90 mol%) and ternary (CO2/N-2/CH4; 5/10/85 mol%) gas mixtures at different pressure rates (50, 150 and 300 psi). The perm-selectivity properties of the MMMs membranes show an improvement in their values about 30% higher compared to the PBI polymeric membranes, favoring the permeation of CO2 and N-2.