Ke Wang,Pengfei Zhao,Ting Zhou,Yanjun Wu,Tianyu Wang,Paul S. Fennell,Edward J. Anthony
CO 2 capture and utilization to produce value-added fuels and chemicals offers a promising avenue to assist in the mitigation of the global warming crisis. However, there are economic challenges for the regeneration of some sorbents used in CO 2 capture, owing to sorbent sintering and high energy requirements, while direct conversion processes are hindered by the lack of cost-effective, efficient, selective, and stable catalysts. We demonstrate the use of sodium zirconate-looping (NaL) with the reverse-Boudouard (RB) reaction enabling high-temperature CO 2 capture and in-situ CO 2 conversion operating in a single isothermal reactor operating at 800 °C. While employing a mild combustion synthesis method, the dual-function material Na 2 ZrO 3 exhibited a high and stable CO 2 uptake capacity of 4.9 mmol CO 2 /g without the use of Ni catalysts. This is due to its fine particle size, macroporous structure, and well-dispersed ZrO 2 stabilizer within the Na 2 O matrix. The resulting Na 2 CO 3 -ZrO 2 and regenerated Na 2 ZrO 3 phases (as synergistic self-catalysts) mixed with renewable and cost-effective biochar (as a reductant) facilitated exceptional in-situ CO 2 conversion efficiency (~90 %), as well as high CO selectivity (approaching 100 %), and relative stability (~80 %) even after multiple cycles. Importantly, theoretical calculations aligned with mechanistic studies revealed that the activation energy barriers at two specific oxygen sites for the monatomic C-assisted CO 2 dissociation/gasification were lower than the desorption energy of CO 2 on the Na 2 ZrO 3 (101) surface, demonstrating the self-catalytic mechanism. Thus, this cost-effective and energy-efficient strategy provides a compelling prospect to make local emissions from large stationary sources CO 2 neutral without requiring carbon sequestration.
Weidong Wang,Ying Gao,Meijie Sun,Zhiqiang Xu,Yanan Tu
Coal gasification fine slag (CGFS) is a solid waste produced during the gasification process, and its high carbon content limits its large-scale utilization. However, the preparation of amine modified hierarchical porous carbon adsorbents (HPCs) from CGFS not only reduces the production costs of matrix materials but also achieves high-value utilization. In this study, the high-carbon component of CGFS was utilized as the raw material to successfully synthesize an amine-modified HPCs for coupled CO 2 capture and mineralization via pre-impurity removal, chemical activation, and amine impregnation. Results demonstrated that HPCs exhibited excellent CO₂ adsorption performance. Specifically, the CO₂ adsorption capacities of 20 % PEI@HPC and 10 % TEPA@HPC with optimal amine loading reached 2.11 mmol/g and 1.62 mmol/g at 298 K, respectively. Both demonstrated outstanding CO₂ adsorption-desorption cycling performance and stability after 10 cycles. Furthermore, the amine-modified HPCs effectively enhanced the carbonation efficiency of desilicated slag, with 20 % PEI@HPC and 30 % TEPA@HPC increasing the mineralization efficiency of the desilicated slag from 28.68 % to 75.01 % and 82.69 %, respectively. Finally, this study elucidated the mechanism of coupled CO₂ capture and mineralization with amine-modified HPCs. The adsorption isotherm models revealed that CO₂ adsorption on the amine-modified HPCs was influenced not only by physical adsorption but also through chemical adsorption dominated by amine functional groups. In this study, a cost-effective CGFS was used as the raw material to synthesize amine-modified HPCs with excellent CO 2 adsorption performance. This approach was expected to address the issues of single-source and expensive matrix materials and had some potential for industrial- scale utilization.
危险品化学品经营许可证（带存储）