Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
Nanotechnology and Functional Materials Division, Department of Materials Science and Engineering, The Ångström Laboratory, Uppsala University, 752 37 Uppsala, Sweden.
Int J Mol Sci. 2023 Jan 24;24(3):2321. doi: 10.3390/ijms24032321.
For the first time, the use of stannate-based sorbents was investigated as high temperature CO sorption to evaluate their potential to contribute towards reducing carbon emissions. The sorption capacity and kinetics of commercial tin oxide, sodium, potassium and calcium stannates and lab synthesised potassium stannates were tested using thermogravimetric analysis. Commercial KSnO was found to possess the largest CO uptake capacity (2.77 mmol CO/g or 12.2 wt%) at 700 °C, which is among the highest for potassium sorbents, but the CO desorption was not successful. On the contrary, the in-house synthesised K-stannate (K-B) using facile solid-state synthesis outperformed the other sorbents, resulting in a CO uptake of 7.3 wt% after 5 min, an adsorption rate (0.016 mg/s) one order of magnitude higher than the other stannates, and stability after 40 cycles. The XRD and XPS analyses showed that K-B contains a mixture of KSnO (76%) and KSnO (21%), while the Scherrer crystal sizes confirmed good resistance to sintering for the potassium stannates. Among the apparent kinetic model tested, the pseudo-second order model was the most suitable to predict the CO sorption process of K-B, indicating that chemical adsorption is dominant, while film-diffusion resistance and intra-particle diffusion resistance governed the sorption process in K-B. In summary, this work shows that solid-state synthesised potassium stannate could be an effective sorbent for high temperature separation, and additional work is required to further elucidate its potential.
首次研究了基于锡酸盐的吸附剂在高温 CO 吸附中的应用，以评估其在减少碳排放方面的潜力。使用热重分析测试了商业氧化锡、氧化钠、氧化钾和氧化钙锡酸盐以及实验室合成的氧化钾锡酸盐的吸附容量和动力学。在 700°C 下，商业 KSnO 具有最大的 CO 吸收容量（2.77 mmol CO/g 或 12.2 wt%），这在钾吸附剂中是最高的之一，但 CO 解吸并不成功。相比之下，使用简便的固态合成法合成的内部 K-锡酸盐（K-B）表现优于其他吸附剂，在 5 分钟后 CO 吸收量为 7.3 wt%，吸附速率（0.016 mg/s）比其他锡酸盐高一个数量级，经过 40 次循环后仍保持稳定。XRD 和 XPS 分析表明，K-B 含有 KSnO（76%）和 KSnO（21%）的混合物，而谢乐晶体尺寸证实了钾锡酸盐对烧结的良好抗性。在所测试的明显动力学模型中，准二级模型最适合预测 K-B 的 CO 吸附过程，表明化学吸附占主导地位，而膜扩散阻力和内颗粒扩散阻力控制了 K-B 中的吸附过程。综上所述，这项工作表明，固态合成的钾锡酸盐可能是一种有效的高温分离吸附剂，需要进一步研究以阐明其潜力。
