Studies on Chloroacylation Reaction Process of Crosslinked Polystyrene Microspheres with ω-Chloroacyl Chloride as Reagent

Quaternary functionalized mesoporous adsorbents for ultra-high kinetics of CO2 capture from air

Obstacles to widespread deployments of direct air capture of CO2 (DAC) lie in high material and energy costs. By grafting quaternary ammonium (QA) functional group to mesoporous polymers with high surface area, a unique DAC adsorbent with moisture swing adsorption (MSA) ability and ultra-high kinetics was developed in this work. Functionalization is designed for efficient delivery of QA group through mesopores to active substitution sites. This achieved ultra-high kinetics adsorbent with half time of 2.9 min under atmospheric environment, is the highest kinetics value reported among DAC adsorbents. A cyclic adsorption capacity of 0.26 mmol g-1 is obtained during MSA process. Through adsorption thermodynamics, it is revealed that adsorbent with uniform cylindrical pore structure has higher functional group efficiency and CO2 capacity. Pore structure can also tune the MSA ability of adsorbent through capillary condensation of water inside its mesopores. The successful functionalization of mesoporous polymers with superb CO2 adsorption kinetics opens the door to facilitate DAC adsorbents for large-scale carbon capture deployments.

Synthesis of thiourea-immobilized polystyrene nanoparticles and their sorption behavior with respect to silver ions in aqueous phase

Although a thiourea-immobilized polystyrene sorbent has been reported to exhibit high Ag⁺ sorption capacity (135mg/g), it is not stable under the acidic conditions commonly employed for desorption. In this research, we synthesized novel thiourea-immobilized polystyrene (TA-PS) nanoparticles to be highly acid resistant via a two-step procedure from polystyrene nanoparticles: acetylation and the subsequent immobilization of thiourea. We investigated the influences of pH, contact time, and initial concentration of AgNO₃ solution on the Ag⁺ sorption of the polymer nanoparticles and estimated the maximum Ag⁺ sorption capacity to be 190±5mg/g at a pH of 6. The sorption performance did not significantly decrease in tap water containing competing ions. The sorption kinetic data were well fitted to the pseudo-second-order kinetic model. Overall, the TA-PS nanoparticles exhibited a high Ag⁺ sorption capacity and high selectivity against alkaline and alkaline earth-metal ions. In particular, their high acid resistance allows them to be used for long time periods in sorption-desorption processes.