Kobylinska Natalia, Puzyrnaya Liubov, Pshinko Galina
Dumansky Institute of Colloid and Water Chemistry, National Academy of Sciences of Ukraine 42 Akad. Vernadsky Blvd. Kyiv 03142 Ukraine
RSC Adv. 2022 Nov 9;12(50):32156-32172. doi: 10.1039/d2ra05503a.
The efficient removal of U(vi) ions from contaminated natural waters and wastewaters of industrial processing plants by novel magnetic nanocomposites based on magnetite and Zn,Al-layered double hydroxides intercalated with citric and EDTA groups (FeO/Zn,Al-LDH/Cit and FeO/Zn,Al-LDH/EDTA) was shown. These adsorbents were obtained using co-precipitation and ion-exchange techniques. The infrared spectroscopy confirmed the existence of O-containing groups on the surfaces of FeO/Zn,Al-LDH/Cit and FeO/Zn,Al-LDH/EDTA, which could provide active sites in the interlayer of the adsorbents for the pollutants removal. The intercalation of Zn,Al-LDH with chelating EDTA-groups significantly increased the adsorption capacity toward U(vi) ions (131.22 mg g) compared to citric moieties in a wide range of pH (3.5-9.0). The maximum adsorption capacities of U(vi) at pH 7.5 were 81.12 mg g for FeO/Zn,Al-LDH/EDTA and 21.6 mg g for FeO/Zn,Al-LDH/Cit. The higher adsorption capacity of FeO/Zn,Al-LDH/EDTA the citric sample might be explained by high affinity of LDH-supports and high-activity of the chelating groups in formation of the complexes in the interlayer space of the magnetic nanocomposite. The removal of U(vi) by the magnetic nanocomposites occurred due to interlayer complexation and electrostatic interactions. The cations (Na, K, Ca), HCO and fulvic acid anions being typical for natural waters were practically not affected upon the removal of U(vi) from aqueous media. The adsorption performance of FeO/Zn,Al-LDH/EDTA nanocomposites was evaluated in the analysis of environmental and wastewater samples with recoveries in the range of 95.8-99.9%. This superior intercalation performance of LDH-supports provides simple and low-cost adsorbents, providing a strategy for decontamination of radionuclides from wastewater.
研究表明，基于磁铁矿以及插层有柠檬酸根和乙二胺四乙酸根（FeO/Zn,Al-LDH/Cit和FeO/Zn,Al-LDH/EDTA）的Zn,Al层状双氢氧化物的新型磁性纳米复合材料，能够有效地从受污染的天然水和工业加工厂废水中去除U(vi)离子。这些吸附剂是通过共沉淀和离子交换技术制备的。红外光谱证实了FeO/Zn,Al-LDH/Cit和FeO/Zn,Al-LDH/EDTA表面存在含O基团，这些基团可为吸附剂层间提供活性位点以去除污染物。与柠檬酸部分相比，插层有螯合乙二胺四乙酸根的Zn,Al-LDH在较宽的pH范围（3.5 - 9.0）内显著提高了对U(vi)离子的吸附容量（131.22 mg/g）。在pH 7.5时，FeO/Zn,Al-LDH/EDTA对U(vi)离子的最大吸附容量为81.12 mg/g，FeO/Zn,Al-LDH/Cit为21.6 mg/g。FeO/Zn,Al-LDH/EDTA比柠檬酸样品具有更高的吸附容量，这可能是由于LDH载体的高亲和力以及螯合基团在磁性纳米复合材料层间空间形成配合物时的高活性。磁性纳米复合材料对U(vi)的去除是由于层间络合和静电相互作用。天然水中典型的阳离子（Na、K、Ca）以及HCO和富里酸阴离子在从水介质中去除U(vi)时几乎不受影响。在环境和废水样品分析中评估了FeO/Zn,Al-LDH/EDTA纳米复合材料的吸附性能，回收率在95.8 - 99.9%范围内。LDH载体这种优异的插层性能提供了简单且低成本的吸附剂，为从废水中去除放射性核素提供了一种策略。
