Cost-Effective Nanoporous Hypercross-linked Polymers Could Drastically Promote the CO2 Absorption Rate in Amine-Based Solvents, Improving Energy-Efficient CO2 Capture

Abstract

Energy-efficient solvents with favorable thermodynamic properties that offer significantly low regeneration energy to the state-of-the-art CO2 capture technologies are typically limited by slow reactivity with CO2. To compensate for low absorption rates, herein, we report that the nonporous hypercross-linked polymeric (HCP) networks as rate promoters are capable of drastically accelerating CO2 absorption in N-methyldiethanolamine (MDEA) sorbents. It is a new topic toward the application of HCPs. Two HCPs were synthesized from cost-effective monomers: polystyrene (HCP-S) and benzene (HCP-B), and then the novel slurry solvents were prepared by suspending HCP-S and HCP-B in MDEA solutions. Benefiting from the inherent properties, HCP-S and HCP-B increased the overall rates of CO2 absorption in the MDEA solution by 253 and 130%, respectively, compared to the blank MDEA. The effect of temperature and amine concentration on the promoting performance of HCP-B was investigated. HCP-B promotes CO2 sorption in the whole temperature range from 25 to 80 °C, and at 2 to 4 molar concentrations of MDEA. The promoting effect of HCP-B was also observed in the DEA solvent, demonstrating that it is not unique to MDEA. Moreover, 13C NMR analysis was used to confirm the promoting effect of the network on CO2 sorption, and a possible mechanism was investigated.