Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin, 541004, Guangxi, People's Republic of China.
Environ Sci Pollut Res Int. 2024 Mar;31(14):21267-21278. doi: 10.1007/s11356-024-32252-x. Epub 2024 Feb 22.
High-temperature solid adsorbent LiSiO has received broad attention due to its high theoretical adsorption capacity, high regeneration capacity, and wide range of raw materials for preparation. In this paper, a LiSiO adsorbent was prepared by MCM-48 as the silica precursor and modified by doping with metal ions (Ca and Na) for high-temperature capture of low-concentration CO. The results showed that the surface of the Ca-doped (or Na-doped) LiSiO adsorbent developed some particles that are primarily composed by LiCaSiO (or LiNaSiO). Furthermore, the grains of the adsorbents became finer, effectively increasing the specific surface area and enhancing adsorption performance. Under 15 vol% CO, the maximum CO adsorption was 25.63 wt% and 32.86 wt% when the Ca doping amount was 0.06 and the Na doping amount was 0.12, respectively. These values were both higher than the adsorption capacity before the metal ion doping. After 10 adsorption/desorption cycles, the adsorption capacity of Na-doped LiSiO increased by 9.68 wt%, while that of Ca-doped LiSiO decreased by 7.98 wt%. This difference could be attributed to the easy sintering of the Ca-containing adsorbent. Furthermore, a biexponential model was used to fit the CO adsorption curve of the adsorbent in order to study the adsorption kinetics. Compared to the conventional LiSiO, the Ca/Na-doped adsorbent offers several advantages, such as a high CO adsorption capacity and stable cycling ability.
高温固体吸附剂 LiSiO 由于其理论吸附容量高、再生容量高以及制备原料范围广而受到广泛关注。本文以 MCM-48 为硅源前驱体制备 LiSiO 吸附剂，并通过掺杂金属离子（Ca 和 Na）进行改性，用于高温捕获低浓度 CO。结果表明，Ca 掺杂（或 Na 掺杂）的 LiSiO 吸附剂表面形成了一些主要由 LiCaSiO（或 LiNaSiO）组成的颗粒。此外，吸附剂的颗粒变得更细，有效增加了比表面积并提高了吸附性能。在 15 vol% CO 下，当 Ca 掺杂量为 0.06 和 Na 掺杂量为 0.12 时，最大 CO 吸附量分别为 25.63 wt%和 32.86 wt%，均高于金属离子掺杂前的吸附容量。经过 10 次吸附/脱附循环后，Na 掺杂 LiSiO 的吸附容量增加了 9.68 wt%，而 Ca 掺杂 LiSiO 的吸附容量减少了 7.98 wt%。这种差异可能归因于含 Ca 吸附剂的易烧结。此外，采用双指数模型对吸附剂的 CO 吸附曲线进行拟合，以研究吸附动力学。与传统的 LiSiO 相比，Ca/Na 掺杂的吸附剂具有高 CO 吸附容量和稳定的循环能力等优点。
