Abstract: The control of CO₂ emission by using sodium-based solid sorbents is receiving attention increasingly because of low reaction temperature and low energy consumption. However, there is a primary drawback for it, i.e. low reactivity with CO₂ during sorption process. So, a modified sodium-based solid sorbent, Na₂CO₃/NaHCO₃ supported on alumina and modified by TiO₂, was proposed for CO₂ capture and characterized by SEM, XRD and TG. The results indicate that TiO₂ is stable in whole range of operation temperature of capturing CO₂ process and after use there is no formation of Ti compounds except TiO₂. More importantly, after dopping TiO₂ the CO₂ capacity of the sorbent increases and its reaction rate with CO₂ goes also up. The reaction products are NaHCO₃ and Na₅H₃(CO₃)₄. However if too much TiO₂ was doped, block of sorbent microstructure could take place, leading to unfavourable effect on the CO₂ capture process.

Key words: CO₂ capture, Na₂CO₃/Al₂O₃, TiO₂, TGA test, dope

摘要： 钠基固体吸收剂脱除燃煤烟气CO₂技术具有反应温度低、能耗低等优点，日益受到学术界的关注。该技术的主要不足是吸收剂的活性成分碳酸钠与CO₂的反应（碳酸化反应）活性较低。针对这一问题，本文旨在研制一种新型改性钠基固体吸收剂，采用活性氧化铝作为载体、TiO₂作为掺杂剂进行改性，利用热重分析装置、XRD、SEM和氮吸附仪研究钠基固体吸收剂的CO₂捕捉性能。结果表明：掺杂TiO₂后，钠基固体吸收剂与CO₂的反应速率加快，CO₂捕捉量增加；反应前后除TiO₂外无其他含Ti化合物生成；碳酸化反应产物为NaHCO₃和Na₅H₃（CO₃）₄；然而TiO₂掺杂过多会堵塞吸收剂的微观孔道，不利于甚至阻碍碳酸化反应的进行，因此，TiO₂的掺杂量应控制在一定的范围内。

关键词: CO₂捕捉, Na₂CO₃/Al₂O₃, TiO₂, 热重, 掺杂