Cyclic Performance of Waste-Derived SiO2 Stabilized, CaO-Based Sorbents for Fast CO2 Capture

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• 作者：Feng Yan ; Jianguo Jiang ; Kaimin Li ; Sicong Tian ; Zongwen Liu ; Jeffrey Shi ; Xuejing Chen ; Jingyuan Fei ; Yuxiang Lu
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2016
• 出版时间：December 5, 2016
• 年：2016
• 卷：4
• 期：12
• 页码：7004-7012
• 全文大小：509K
• ISSN：2168-0485

文摘

Calcium-looping technology has been identified as one of the most favorable CO₂ capture techniques for the implementation of carbon capture, utilization, and storage (CCUS); however, the rapid deactivation of CaO sorbents due to sintering is currently a major barrier of this technology. We report for the first time an environmentally benign and cost-effective strategy to reduce sintering by adding waste-derived nanosilica, synthesized from photovoltaic waste (SiCl₄), into Cao-based sorbents through a simple dry mixing procedure. The as-synthesized sorbent (90% CaCO₃–W) resulted in final CO₂ uptake of 0.32 g(CO₂) g(CaO)⁻¹ within 5 min of carbonation. Even under the most severe calcination conditions (at 920 °C in pure CO₂), it still maintained a stable capture capacity, with CO₂ uptake of 0.23 g(CO₂) g(CaO)⁻¹ after 30 cycles. Additionally, the CO₂ uptake percentage reached ∼90% in the fast carbonation stage (∼20 s), which is of great significance for real applications. The most likely stabilization mechanism was considered on the basis of N₂ physisorption isotherms and X-ray diffraction patterns. It was concluded that stable and refractory larnite (Ca₂SiO₄) particles were formed during 2-h thermal pretreatment at 900 °C, leading to sintering resistance. This strategy significantly enhanced the cyclic stability and carbonation rate of CaO-based sorbents through the reuse of SiCl₄ and is thus a green technology for scaled-up fast CO₂ capture.