Alkali-Doped Lithium Orthosilicate Sorbents for Carbon Dioxide Capture

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• 作者：Xinwei Yang ; Dr. Wenqiang Liu ; Jian Sun ; Yingchao Hu ; Wenyu Wang ; Hongqiang Chen ; Dr. Yang Zhang ; Dr. Xian Li and Prof. Minghou Xu
• 刊名：ChemSusChem
• 出版年：2016
• 出版时间：September 8, 2016
• 年：2016
• 卷：9
• 期：17
• 页码：2480-2487
• 全文大小：2825K
• ISSN：1864-564X

文摘

New alkali-doped (Na₂CO₃ and K₂CO₃) Li₄SiO₄ sorbents with excellent performance at low CO₂ concentrations were synthesized. We speculate that alkali doping breaks the orderly arrangement of the Li₄SiO₄ crystals, hence increasing its specific surface area and the number of pores. It was shown that 10 wt % Na₂CO₃ and 5 wt % K₂CO₃ are the optimal additive ratios for doped sorbents to attain the highest conversions. Moreover, under 15 vol % CO₂, the doped sorbents present clearly faster absorption rates and exhibit stable cyclic durability with impressive conversions of about 90 %, at least 20 % higher than that of non-doped Li₄SiO₄. The attained conversions are also 10 % higher than the reported highest conversion of 80 % on doped Li₄SiO₄. The performance of Li₄SiO₄ is believed to be enhanced by the eutectic melt, and it is the first time that the existence of eutectic Li/Na or Li/K carbonate on doped sorbents when absorbing CO₂ at high temperature is confirmed; this was done using systematical analysis combining differential scanning calorimetry with in situ powder X-ray diffraction.