Application of polyethylenimine‐impregnated solid adsorbents for direct capture of low‐concentration CO2

A systematic study of CO 2 capture on the amine‐impregnated solid adsorbents is carried out at CO 2 concentrations in the range of 400–5000 ppm, relating to the direct CO 2 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 CO 2 and 2.13 mmol/g for 5000 ppm CO 2 . Moisture plays a promoting effect on CO 2 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 CO 2 capture from ambient air. © 2014 American Institute of Chemical Engineers AIChE J , 61: 972–980, 2015