Research Of The Preparation And The CO₂ Adsorption Performance Of Hollow Spheres Oxide Adsorbents

In recent years,greenhouse effect on the environment which caused by CO2 is becoming increasingly serious,but the capture and storage technology for CO2 has also made great progress.Alkaline metal oxides are extensively studied because they are rich in alkaline sites that can interact with acidic carbon dioxide gases.Among them,magnesium oxide as an adsorbent in the mediate temperature zone(adsorption temperature of 200??400?)with an advantage of high stability and low regeneration temperature,but the adsorption capacity is low;Calcium oxide treated as an adsorbent in the high temperature zone(adsorption temperature>400?)has a high adsorption capacity,but the cycle stability is poor.These defects constrain the application of alkaline metal oxides in the field of carbon dioxide adsorption.In this paper,alkaline metal oxides are prepared into hollow spheres to increase the adsorption capacity of CO2,and the adsorption capacity of the adsorbent in the middle temperature zone and the cycling stability of the adsorbent in the high temperature zone were improved by doping MgO with CaO.In the preparation of hollow spheres oxides,colloidal carbon balls as the template were firstly synthesis by hydrothermal reaction of the glucose solution for 10h;MgO hollow spheres adsorbents and different Mg-Ca ratios(Mg/Ca=1,14,19,24,49)of MgO/CaO hollow spheres adsorbents are prepared with colloidal carbon balls as the template.The morphology and structure of the adsorbents were characterized by SEM,TEM and XRD,and it was found that Ca2+ was more easily adsorbed on the surface of colloidal carbon spheres than Mg2+,but the ratio of Mg2+ and Ca2+ had no significant effect on the morphology of hollow spheres.The adsorption performance of hollow spheres oxide adsorbents were tested by TGA.The results show that the adsorption capacity of CO2 with MgO hollow spheres is 2.54%at the best temperature of 350?,which is nearly 5 times higher than that of ordinary MgO(0.55%).For the mixed oxide adsorbents,in the mediate temperature zone,the best adsorption performance is showed under the conditions of 300?,the heating rate of 10?/min and Mg/Ca ratio of 19,and the maximum adsorption capacity of 3.67%;In the high temperature zone,the best adsorption performance is showed under the conditions of 700?,the heating rate of 10?/min and Mg-Ca ratio of 14,and the maximum adsorption capacity of 38.92%,the descent is only 1.31%after 30 cycles.