With the increasingly serious problem of climate warming in recent years, CO₂ capture technology has been widely concerned by countries all over the world. One of the effective methods to reduce CO₂ emissions is to capture CO₂ after combustion. Alkali metal salt modified MgO-based adsorbents were synthesized by hydration impregnation method to obtain high efficient adsorbents in this study. The CO₂ cyclic adsorption capacity test was carried out in a fixed bed experimental setup. The microstructure of the adsorbent was characterized by XRD, SEM and BET techniques. The adsorption properties and cycle stability of alkali metal salts modified MgO adsorbents were deeply studied. The results show that the adsorbent with 10 wt% K₂CO₃-MgO has the best adsorption performance and cyclic stability. The initial adsorption capacity is 89 mg/g·sorbent, and the adsorption capacity of the 15th cycle is 63 mgCO₂/ g·sorbent. 10 wt% K₂CO₃-MgO adsorbent has the largest specific surface area, and K₂CO₃ doping of alkali metal carbonate can effectively improve the CO₂ adsorption capacity and cyclic stability of the adsorbent.

Keywords: CO₂ adsorbent, MgO, Alkali metal salt, Adsorption capacity, Cyclic stability.