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.
Sci Total Environ. 2021 Mar 10;759:143483. doi: 10.1016/j.scitotenv.2020.143483. Epub 2020 Nov 10.
Through swelling/restoration reaction, benzamidoxime (BAO) is introduced into MgAl-LDH interlayers to assemble a new composite of MgAl-BAO-LDH (abbr. BAO-LDH). Wet samples of the BAO-LDH obtained by washing with diverse solvents are present in colloidal state, which facilitates the fabrication of thin film adsorbents convenient for actual application. After drying, the assembled sample exhibits floral morphology composed of thin nanosheets, much different from hexagonal morphology of NO intercalated MgAl-LDH precursor (NO-LDH), demonstrating a phenomenon rarely found in swelling/restoration. The BAO-LDH depicts an extremely large maximum sorption capacity (q) of 327 mg·g and ultra-high selectivity for U. At low U concentrations (5-10 ppm), nearly complete capture (~100%) is achieved in a wide pH range of 3-11, while at high U concentrations (110 ppm), quite high U removals (≥93.0%) are obtained at pH = 6-8, meaning perfect suitability for trapping U from seawater. For natural seawater containing trace amounts of U (3.93 ppb) coexisting with high concentration of competitive ions, the BAO-LDH displays significantly high U removal (87%). Complexation between interlayer BAO (N and O as ligands) with UO and synergistic interactions of LDH layer hydroxyls with UO contribute to the highly effective uranium capture. All results demonstrate the BAO-LDH is a promising adsorbent applied in seawater uranium extraction and nuclear wastewater disposal.
通过肿胀/恢复反应，苯甲脒肟（BAO）被引入 MgAl-LDH 夹层中，组装成一种新的 MgAl-BAO-LDH（简称 BAO-LDH）复合材料。用不同溶剂洗涤得到的 BAO-LDH 的湿样品呈胶体状态，便于制备便于实际应用的薄膜吸附剂。干燥后，组装后的样品呈现出由薄纳米片组成的花朵形态，与 NO 插层 MgAl-LDH 前体（NO-LDH）的六边形形态有很大的不同，这在肿胀/恢复反应中很少见。BAO-LDH 表现出极高的最大吸附容量（q）为 327 mg·g，对 U 具有超高选择性。在低 U 浓度（5-10 ppm）下，在 3-11 的宽 pH 范围内几乎可以实现完全捕获（~100%），而在高 U 浓度（110 ppm）下，在 pH = 6-8 时可以获得相当高的 U 去除率（≥93.0%），非常适合从海水中捕获 U。对于含有痕量 U（3.93 ppb）的天然海水和共存的高浓度竞争离子，BAO-LDH 显示出非常高的 U 去除率（87%）。夹层 BAO（N 和 O 作为配体）与 UO 之间的络合以及 LDH 层羟基与 UO 之间的协同相互作用有助于实现高效的铀捕获。所有结果都表明，BAO-LDH 是一种很有前途的吸附剂，可用于海水铀提取和核废水处理。
