Membrane materials and fabrication for gas separation

Abstract

The objective of this study is to evaluate the use of commercially available polyimides as the precursor to prepare the high performance membranes for gas separation. Various instruments were employed to characterize the separation properties of membranes. Emphases were put on the separation of CO2/CH4, O2/N2 and He/N2. Firstly, cross-linking modification was performed on polymeric membranes. The effects of cross-linking modification on thermal and gas transport properties of membranes were studied. The results showed that the cross-linking modification improved the separation performance of membranes. Secondly, carbon molecular sieve membranes were prepared through pyrolysis of polyimides. Two novel pretreatment approaches, namely cross-linking modification and nonsolvent treatment, were developed. The high productive and selective CMSMs were produced through the proposed pretreatments. Lastly, a new membrane material, carbon-zeolite composite membrane with excellent separation performance was presented. The composite membranes possessed good separation properties with combining the advantages of carbon membranes and zeolite materials.