Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, New York 13699, United States.
Department of Physics, Clarkson University, Potsdam, New York 13699, United States.
ACS Appl Mater Interfaces. 2020 Nov 25;12(47):52788-52796. doi: 10.1021/acsami.0c16477. Epub 2020 Nov 16.
Phosphate removal has become a critical need to mitigate the negative effect of water eutrophication, which is responsible for the overgrowth of toxic algal blooms and the significant ecological harm generated to aquatic ecosystems. However, some of the currently available adsorbents have low removal capacity and function optimally at specific pH ranges. Here, we present an example of a cerium-based metal-organic framework (MOF) as a high-capacity sorbent for phosphate removal from eutrophic waters. Specifically, a Ce(IV)-based UiO-66 analogue, Ce 1,4-benzenedicarboxylate (Ce-BDC), was selected due to its water stability, high surface area, microporous structure, and the high binding affinity of phosphate with its open metal sites. Mechanistic studies supported by density functional theory (DFT) calculations indicate the formation of a Ce-O-P bond through ion exchange between the terminal (nonbridging) hydroxyl groups at the missing linker sites and the phosphate adducts. Experimental results demonstrate that Ce-BDC is highly selective for phosphates over other common anions (Cl, Br, I, NO, HCO, SO) and stable in a broad pH range of (2-12), covering the relevant range for the treatment of contaminants in aquatic systems. The sorbent shows a fast removal rate, capturing significant amounts of phosphate within 4 min with a maximum adsorption capacity of 179 mg·g, outperforming other porous materials. These results show a remarkable adsorption capacity and fast kinetics compared with the current state-of-the-art crystalline porous materials. This study may advance the design of new microporous materials with high adsorption capabilities, good stability, and make a significant contribution to the development of future generation technology to mitigate the negative effects of water eutrophication.
去除磷酸盐已成为减轻水体富营养化负面影响的关键需求，水体富营养化会导致有毒藻类大量繁殖，并对水生态系统造成重大生态危害。然而，一些现有的吸附剂去除能力较低，并且在特定的 pH 值范围内才能发挥最佳作用。在这里，我们提出了一种基于铈的金属有机骨架（MOF）作为从富营养水中去除磷酸盐的高容量吸附剂的示例。具体来说，选择了基于 Ce(IV)的 UiO-66 类似物，Ce1,4-苯二甲酸酯（Ce-BDC），因为它具有水稳定性、高表面积、微孔结构以及磷酸盐与开放金属位的高结合亲和力。密度泛函理论（DFT）计算支持的机理研究表明，通过在缺失连接体位点的末端（非桥接）羟基与磷酸盐加合物之间的离子交换，形成了 Ce-O-P 键。实验结果表明，Ce-BDC 对磷酸盐具有高度选择性，优于其他常见阴离子（Cl、Br、I、NO、HCO、SO），并且在宽 pH 范围（2-12）内稳定，涵盖了处理水系统中污染物的相关范围。该吸附剂具有快速的去除速率，在 4 分钟内可捕获大量的磷酸盐，最大吸附容量为 179 mg·g，优于其他多孔材料。与当前最先进的结晶多孔材料相比，这些结果显示出了显著的吸附能力和快速的动力学性能。这项研究可能会推动具有高吸附能力、良好稳定性的新型微孔材料的设计，并为开发未来减轻水体富营养化负面影响的新一代技术做出重要贡献。
