Fabrication of Cu-BTC Metal Organic Frameworks on PVDF Hollow Fiber Membrane for Gas Separation via Multiple Reactions

Cu-BTC/PVDF composite membranes were prepared by immersing PVDF hollow fiber supporting membranes into copper acetate aqueous solution and trimesic acid ethanol solution repeatedly. Surface and cross sectional morphologies of Cu-BTC crystals on the supporting PVDF membrane were investigated using SEM. Chemical composition and crystal structure of Cu-BTC were characterized by IR and XRD. Gas permeance and separation factor for CO2 and N-2 of the Cu-BTC/PVDF composite membrane were recorded under different pressures. The results illustrated that with increasing reaction times, the crystal layer became more in density and less in defects, resulting in decrease of gas permeance and the separation mechanism changing from convective flow to Knusen diffusion.