NaNO₃-Promoted MgO-Based Adsorbents Prepared from Bischofite for CO₂ Capture: Experimental and Density Functional Theory Study

Abstract

MgO has broad application potential in CO 2 capture at intermedium temperatures. In this paper, the effects of NaNO 3 doping on the properties of MgO prepared by using waste bischofite as the raw material were investigated to improve the performance of the CO 2 capture. MgO-doped NaNO 3 exhibited excellent CO 2 capture performance at 320 °C with a maximum adsorption capacity of 36.62 wt %. MgO-doped NaNO 3 has good cycling stability after 10 adsorption−desorption cycle experiments. In addition, CO 2 adsorption on pure MgO and MgO−NaNO 3 surfaces was investigated in accordance with density functional theory. Calculation results show that doping with NaNO 3 allows more electrons to be transferred from the MgO substrate to the CO 2 molecule. MgO-doped NaNO 3 can lead to an increase in adsorption energy, resulting in a more stable structure after adsorption and thereby promoting adsorption. The result of this study provides an effective method for the comprehensive utilization of salt lake resources.