State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China.
State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China.
Sci Total Environ. 2023 Jul 10;881:163525. doi: 10.1016/j.scitotenv.2023.163525. Epub 2023 Apr 15.
A novel dopamine-supported Mg(Ca)Al layered double hydroxide composite was synthesized by co-precipitation method. The existence of Ca and dopamine could promote the capture of uranium on the layered double hydroxides. In batch experiments, the composite exhibited good uranium removal performance, including high adsorption capacity (687.3 mg/g), strong anti-interference and good reusability (the removal percentage was still higher than 90 % after five cycles). At low initial uranium concentration, the uranium removal percentage on the composite exceeded 99.7 % and the residual concentration of uranium in the solution was <0.03 mg/L, reaching the limited standard of the World Health Organization. The studies of adsorption kinetics and isotherm indicated that the uranium adsorption behavior on the composite conformed to the pseudo-second-order kinetic and Langmuir isotherm models, suggesting that the process was a monolayer adsorption dominated by chemical adsorption. Furthermore, the high-efficiency uranium adsorption on the Mg(Ca)Al layered double hydroxide was mainly attributed to the strong complexation between the active sites (-OH and -NH) and uranium, the precipitation of interlayer intercalation ions (CO and OH) to uranium and the ion exchange of Ca to uranium. Due to these advantages, the dopamine-supported Mg(Ca)Al layered double hydroxide composite is expected to be used as fine adsorbent to remove uranium from wastewater.
一种新型多巴胺支持的 Mg(Ca)Al 层状双氢氧化物复合材料通过共沉淀法合成。Ca 和多巴胺的存在可以促进铀在层状双氢氧化物上的捕获。在批实验中，该复合材料表现出良好的铀去除性能，包括高吸附容量（687.3mg/g）、强抗干扰性和良好的可重复使用性（经过五次循环后去除率仍高于 90%）。在初始铀浓度较低的情况下，复合材料对铀的去除率超过 99.7%，溶液中铀的残留浓度<0.03mg/L，达到世界卫生组织的限量标准。吸附动力学和等温线研究表明，铀在复合材料上的吸附行为符合拟二级动力学和 Langmuir 等温线模型，表明该过程是一种单层吸附，主要由化学吸附主导。此外，Mg(Ca)Al 层状双氢氧化物对铀的高效吸附主要归因于活性位点（-OH 和 -NH）与铀之间的强络合、层间插入离子（CO 和 OH）对铀的沉淀以及 Ca 对铀的离子交换。由于这些优势，多巴胺支持的 Mg(Ca)Al 层状双氢氧化物复合材料有望用作精细吸附剂，从废水中去除铀。
