Synthesis of dual-functionalized APTES-Bentonite/PVDF mixed-matrix membranes for the efficient separation of CO2/CH4 and CO2/N2

Abstract

In response to global climate change, most countries have set carbon reduction targets. Mixed matrix membranes (MMMs), which combine the characteristics of inorganic nanofillers and organic matrices, have received wide attentions because of their good permeability and selective performance for the separation of CO2 from industrial waste gases. However, the poor dispersion, compatibility and interfacial defects often lead to poor gas separation performance. In this paper, according to the dissolution-diffusion and Lewis acid-base theories, inorganic filler of amino-functionalized Bentonite (APTES-Bentonite) with -NH2 was firstly synthesized to improve the affinity of CO2. Then, the dual-functionalized MMMs of APTES-Bentonite/PVDF (A-B/P MMMs) was prepared and adopted for the separation of CO2/CH4 and CO2/N2, showing the increase of 87.76% and 75.31% compared to the pristine PVDF membrane, respectively. These excellent performances were attributed to the synergistic effect of APTES-Bentonite with -NH2 groups and PVDF with -F groups, which provide a dual-functional transport pathway for CO2 molecules due to the interactions of host-guest. Overall, the customized A-B/P MMMs offer superior CO2 separation performance, which provides some valuable references for large-scale CO2 capture studies.