Abstract

This paper presented the effect of Ce doping on the structure, morphology and CO₂ adsorption performances of MgO-based adsorbents. Nano MgO-based adsorbents were synthesized by citric acid complexation method using Mg(NO₃)₂·6H₂O and Ce(NO₃)₃·6H₂O as the precursors, and characterized by XRD, SEM, N₂ adsorption/desorption and FT-IR techniques, respectively. The results demonstrated that with Ce incorporation, the crystal sizes of the adsorbents were obviously reduced, and a large number of micropores and mesopores were formed. The CO₂ adsorption of the samples was carried out on a thermogravimetric analyzer, and the adsorption data were fitted by the first-order kinetic equation, the pseudo second-order kinetic equation and the intra-particle diffusion model, respectively. It can be concluded after Ce doping, the adsorption capacity of the adsorbent was greatly improved, due to good dispersity of MgO particles and well-developed porosity, and the increase of the surface reaction rate could be attributed to the increase of BET surface area and the alkaline sites of the Ce-incorporated adsorbents, while the increase of the rate in the diffusion stage was caused by the formation of the porous structure. Therefore, the smaller the crystal size of MgO, the more favorable it was for CO₂ capture. This work provided the inspiration of MgO-based adsorbent for improving CO₂ adsorption.

摘要

本文介绍了Ce掺杂对MgO基吸附剂的结构、形貌和CO ₂吸附性能的影响。以Mg(NO ₃ ) ₂ ·6H ₂ O和Ce(NO ₃ ) ₃ ·6H ₂ O为前驱体，采用柠檬酸络合法合成了纳米MgO基吸附剂，并通过XRD、SEM、N ₂吸附/解吸等手段对其进行了表征。和 FT-IR 技术。结果表明，随着Ce的掺入，吸附剂的晶体尺寸明显减小，形成了大量的微孔和介孔。二氧化碳₂样品的吸附在热重分析仪上进行，吸附数据分别用一级动力学方程、拟二级动力学方程和颗粒内扩散模型拟合。可以得出结论，Ce掺杂后，由于MgO颗粒分散性好，孔隙度发达，吸附剂的吸附能力大大提高，表面反应速率的增加可归因于BET表面积的增加和Ce 吸附剂的碱性位点，而扩散阶段速率的增加是由多孔结构的形成引起的。因此，MgO的晶体尺寸越小，对CO ₂越有利捕获。该工作为基于MgO的吸附剂改善CO ₂吸附提供了启示。