Accelerating CO2 Absorption in Aqueous Amine Solutions at High Temperature with Carbonic Anhydrase in Magnetic Nanogels

Abstract We report a facile method for encapsulation of carbonic anhydrase (CA) with magnetic nanogel (MNP-CA nanogel), in which amino and vinyl groups are first grafted onto the surface of magnetic Fe 3 O 4 nanoparticles (MNP) using 3-aminopropyltriethoxysilane (APTES) and N -acryloylsuccinimide (NAS), followed by CA attachment with glutaraldehyde and in situ polymerization with acrylamide. The MNP-CA nanogel shows much improved thermostability at elevated temperatures, e.g. staying unchanged at 60 °C for 80 min, owing to multiple linkage with the hydrophilic polymer network coated at the MNP surface. Addition of the MNP-CA nanogel into a methyldiethanolamine (MDEA) solution at an ultralow mass ratio (1:10 4 ) is able to enhance the CO 2 absorption rate at 60 °C by 1.45 fold. The CA-enhanced mass transport of the absorbate has been demonstrated in a wetted-wall column, in which the MNP-CA nanogel increases the total mass transfer coefficient in the gas phase (K G ) by 4.61 fold compared with that determined in the MDEA solution. The greatly increased absorption performance and much enhanced stability make MNP-CA nanogel appealing for industrial applications. Graphical Abstract