Alkali Nitrates Molten Salt Modified Commercial MgO for Intermediate-Temperature CO2 Capture: Optimization of the Li/Na/K Ratio

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• 作者：Yaqian Qiao ; Junya Wang ; Yu Zhang ; Wanlin Gao ; Takuya Harada ; Liang Huang ; T. Alan Hatton ; Qiang Wang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2017
• 出版时间：February 15, 2017
• 年：2017
• 卷：56
• 期：6
• 页码：1509-1517
• 全文大小：652K
• ISSN：1520-5045

文摘

The promoting effect of alkali nitrates molten salt on the CO₂ capture capacity of a commercial MgO was investigated in detail. In particular, the ratio of Li/Na/K nitrates and the loading of the molten salt mixture on the MgO particles were optimized, and the influence of calcination and adsorption temperatures was evaluated. The MgO sample doped with 10 mol % (Li_0.3Na_0.6K_0.1)NO₃ was demonstrated to possess the highest CO₂ uptake (up to 16.8 mmol g^–1), which is the highest value reported for MgO based adsorbents in the literature. The CO₂ adsorption/desorption cycling stability was studied using both temperature swing adsorption (TSA) and pressure swing adsorption (PSA). The morphology and structure of the optimized adsorbent, 10 mol % (Li_0.3Na_0.6K_0.1)NO₃·MgO, were characterized thoroughly using XRD, SEM, FTIR, and BET analyses. The thermal stability of doped alkali nitrates was investigated via temperature program desorption and XRD analysis, which indicated that the phase status of the molten salts is crucial for the marked improvement in CO₂ capture capacity of MgO.