Application of Polyethylenimine-Impregnated Solid Adsorbents for Direct Capture of Low-Concentration CO2

A systematic study of CO2 capture on the amine-impregnated solid adsorbents is carried out at CO2 concentrations in the range of 400-5000 ppm, relating to the direct CO2 capture from atmospheric air. The commercially available polymethacrylate-based HP2MGL and polyethylenimine are screened to be the suitable support and amine, respectively, for preparation of the adsorbent. The adsorbents exhibit an excellent saturation adsorption capacity of 1.96 mmol/g for 400 ppm CO2 and 2.13 mmol/g for 5000 ppm CO2. Moisture plays a promoting effect on CO2 adsorption but depends on the relative humidity. The presence of O-2 would lead to the decrease of adsorption capacity but do not affect the cyclic performance. The diffusion additive is efficient to improve the adsorption capacity and cyclic performance. Moreover, the adsorbents can be easily regenerated under a mild temperature. This study may have a positive impact on the design of high-performance adsorbents for CO2 capture from ambient air. (c) 2014 American Institute of Chemical Engineers AIChE J, 61: 972-980, 2015