Multi-component Transport Through Crosslinked Acrylate Based Side Chain Containing Membranes

Abstract

A typical CO2 reduction process includes two half-cells separated by the ion exchange membrane that occurs with the help of suitable cathode catalysts. Being an extremely complicated reaction process, CO2 reduces to a mixture of valuable products such as methanol, ethanol, formate, acetate, etc. One major limitation of this technique is the crossover of those products through the membrane to the anode from the cathode. Here, a significant role is played by the ion exchange membrane, which needs to be selective towards the pertinent ion transport for the reactions to continue, and at the same time, obstruct the transport of CO2 reduction products. The motivation to improve ion exchange membranes for CO2 reduction application is the baseline this dissertation stands upon. This work has investigated the fundamental role of different side chain comonomers in PEGDA-based membranes to mitigate some of the CO2 reduction products transport. In this study, long pendant side chain comonomer, poly (ethylene glycol methyl acrylate) PEGMA’s (n=9) role in altering the PEGDA-based membrane's physiochemical properties, and co-transport of most reported CO2 reduction products is explored both for charge-neutral and cation exchange membranes. This thesis also includes a comparative study about the contribution of other side chain comonomers such as poly (ethylene glycol methyl ether acrylate) (PEGMEA), and poly (ethylene glycol methyl ether methacrylate) (PEGMEMA) in varying the membrane’s important physiochemical properties, and transport behavior of the CO2 reduced products. Also, the different carboxylate salts of increasing hydrophobic chain length’s transport through polyether-based membrane at various upstream salt concentrations is investigated here. The long-term applicability of this dissertation is to add new insights into designing improved ion exchange membranes for CO2 reduction fuel cells, or in applications like membrane-based bioreactors that involve removing volatile fatty acids (VFAs).