Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan, 430074, People's Republic of China.
School of Nuclear Science and Technology, University of South China, Hengyang, 421001, People's Republic of China.
Environ Sci Pollut Res Int. 2023 Feb;30(7):18156-18167. doi: 10.1007/s11356-022-23492-w. Epub 2022 Oct 7.
The production of large amounts of uranium-containing wastewater and its potential hazards has stimulated green and efficient material removal of uranium (VI). Inspired by the natural mineralization of bone, a facile and eco-friendly biomimetic synthesis of nano-hydroxyapatite (HAP) was carried out using chitosan (CS) as a template. It was found that the reaction temperature and the amount of precursors influence the particle size, crystallinity and specific surface area of the CS/HAP nanorods, and consequently their U(VI) adsorption efficiency. Moreover, the synthesized CS/HAP-40 with smaller particle size, lower crystallinity, and larger specific surface area show a more efficient U(VI) removal compared with CS/HAP-55 and CS/HAP-55-AT. It has a maximum adsorption capacity of 294.12 mg·g of the CS/HAP-40. Interestingly, the U(VI) removal mechanism of CS/HAP-40 in acidic (pH = 3) and alkaline (pH = 8) aqueous solutions was found to be different. As one of the main results, the U(VI) adsorption mechanisms at pH 8 could be surface complexation and ion exchange. On the contrary, three different mechanisms could be observed at pH 3: dissolution-precipitation to form chernikovite, surface complexation, and ion exchange.
大量含铀废水的产生及其潜在危害刺激了绿色高效的铀（VI）去除材料的研发。受天然骨矿化的启发，采用壳聚糖（CS）作为模板，通过简便且环保的仿生合成方法制备了纳米羟基磷灰石（HAP）。结果表明，反应温度和前体的用量影响 CS/HAP 纳米棒的粒径、结晶度和比表面积，从而影响其对 U(VI)的吸附效率。此外，与 CS/HAP-55 和 CS/HAP-55-AT 相比，粒径较小、结晶度较低、比表面积较大的合成 CS/HAP-40 对 U(VI)的去除效率更高。其最大吸附容量为 294.12 mg·g 的 CS/HAP-40。有趣的是，在酸性（pH = 3）和碱性（pH = 8）水溶液中，CS/HAP-40 去除 U(VI)的机制不同。作为主要结果之一，在 pH 8 时，U(VI)的吸附机制可能是表面络合和离子交换。相反，在 pH 3 时可以观察到三种不同的机制：形成砷铀云母的溶解-沉淀、表面络合和离子交换。
