Yang Lixiao, Wang Qian, Yao Huiqin, Yang Qishuo, Lu Xiao, Wu Zhenglong, Liu Rong, Shi Keren, Ma Shulan
Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, China.
School of Basic Medical Sciences, Ningxia Medical University, Yinchuan 750004, China.
Dalton Trans. 2022 May 31;51(21):8327-8339. doi: 10.1039/d2dt01278b.
Oxygen-rich pyromellitic acidic anions (PMA) have been intercalated into MgAl-layered double hydroxides to fabricate the MgAl-PMA-LDH (abbr. PMA-LDH) composite exhibiting excellent adsorption performance toward uranium (U(VI)). Benefiting from the large number of functional groups of -COO, the PMA-LDH displays an extremely large maximum U adsorption capacity (Um) of 352 mg g and an ultra-fast sorption rate, reaching uptakes of ∼97% within 30 min and >99% in 1 h at the initial U concentration (U0) of 113 ppm. Over a very wide pH range of 5-11, high U removals (>93%) are achieved at U0 = 105 ppm. Moreover, in the presence of highly concentrated competitive ions, ultra-high selectivity of UO is observed, giving a very large distribution coefficient () of ∼10 mL g. Moreover, the PMA-LDH exhibits effective capture of UO in contaminated simulated seawater, showing high uptakes of >93% at U0 ∼ 10 ppm and >98% at U0 ∼ 100 ppm. The dispersion effect of LDH layers may contribute to the increase of U adsorption capacity, and the confinement effect of LDH is conducive to the improvement of sorption selectivity toward U. The exploration of the interaction mechanism of UO with PMA confined within the LDH gallery offers an important basis for the fabrication of new kinds of organic/inorganic hybrid materials. The PMA-LDH is a highly effective adsorbent which can be applied to uranium extraction from seawater and uranium disposal in nuclear wastewater.
富氧均苯四甲酸酸性阴离子（PMA）已插入到MgAl层状双氢氧化物中，以制备对铀（U(VI)）表现出优异吸附性能的MgAl-PMA-LDH（简称PMA-LDH）复合材料。得益于大量的-COO官能团，PMA-LDH显示出极大的最大铀吸附容量（Um），为352 mg/g，且吸附速率超快，在初始铀浓度（U0）为113 ppm时，30分钟内吸附量达到约97%，1小时内超过99%。在5-11的很宽pH范围内，当U0 = 105 ppm时，铀去除率很高（>93%）。此外，在存在高浓度竞争离子的情况下，观察到对UO的超高选择性，分配系数（）非常大，约为10 mL/g。此外，PMA-LDH在受污染的模拟海水中对UO表现出有效的捕获能力，在U0约为10 ppm时吸附量>93%，在U0约为100 ppm时>98%。LDH层的分散效应可能有助于提高铀吸附容量，而LDH的限域效应有利于提高对铀的吸附选择性。探索UO与限制在LDH层间的PMA的相互作用机制为新型有机/无机杂化材料的制备提供了重要依据。PMA-LDH是一种高效吸附剂，可应用于从海水中提取铀以及处理核废水中的铀。
