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

MgO has broad application potential in CO₂ capture at intermedium temperatures. In this paper, the effects of NaNO₃ doping on the properties of MgO prepared by using waste bischofite as the raw material were investigated to improve the performance of the CO₂ capture. MgO-doped NaNO₃ exhibited excellent CO₂ capture performance at 320 °C with a maximum adsorption capacity of 36.62 wt %. MgO-doped NaNO₃ has good cycling stability after 10 adsorption-desorption cycle experiments. In addition, CO₂ adsorption on pure MgO and MgO-NaNO₃ surfaces was investigated in accordance with density functional theory. Calculation results show that doping with NaNO₃ allows more electrons to be transferred from the MgO substrate to the CO₂ molecule. MgO-doped NaNO₃ 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.