Amino acid-imprinted polymers as highly selective CO2 capture materials

Abstract

The recent atmospheric concentration of CO2 increase to 400 ppm is a cause of global climate change. There is therefore an urgent need for selective and cost-effective CO2 capture technologies. Fossil fuel consumption during energy production and transportation are two major sources of CO2 emission into the atmosphere. The capture of CO2 selectively from gaseous mixtures using reusable adsorbent is thus a challenge. In this article, we report that nanoparticles functionalized with imprinting of amino acids exhibit a significant increase in the selective adsorption capacities of CO2 in a gaseous mixture. Molecular imprinting of taurine in the vinylbenzyl chloride-co-divinyl benzene polymer formed cavities of 1–3 nm size and introduced –SOOH and –N–H functionalities, resulting in a very high CO2 adsorption capacity of 5.67 mmol g−1 at 30 °C/1 bar. The selectivity of CO2 over N2 and CH4 was 87–91% and 83–87%, respectively. The isosteric heat of adsorption (Qst) for CO2 at 298 and 303 K showed an increase in Qst from 36.8 to 47.6 K kJ mol−1, and this would be responsible for high CO2 adsorption energies and faster kinetics. This study reports first-time imprinting of CO2-philic templates in the polymers to capture small gas molecules at ambient conditions, and the results demonstrated that the polymers have a wide scope for real-life applications of CO2 capture.