This study firstly reported a novel nano humboldtine/almandine composite (NHLA composite) prepared directly from almandine through one-pot method based on the interaction of almandine and oxalic acid. The formation of humboldtine/almandine binary phase from natural almandine was determined by X-ray diffraction. Analysis of scanning & transmission electron microscope showed that large amount of nano humboldtine with uniform size (average size of 15.59 nm) were loaded on the almandine sheets. Compared with raw minerals, Pb(Ⅱ) removal capacity of synthesized composite was significantly increased, demonstrating that the main active ingredient for Pb(Ⅱ) removal was humboldtine phase rather than almandine itself. Pb(Ⅱ) adsorption capacity was increased with the increasing of initial pH value or temperature. Langmuir isotherm and Pseudo-second order kinetic equation were well fitted with experimental results and the maximum Pb(Ⅱ) adsorption capacity from Langmuir isotherm was 574.71 mg/g at temperature of 25 °C. In addition, heavy metal removal experiments in coexisting systems of multiple heavy metal ions manifested that the composite had a high selectivity for Pb(Ⅱ) adsorption. Ion exchange, surface complexation and electrostatic interaction have involved in the Pb(Ⅱ) adsorption. The synthesized composite was considered as a low cost, high efficiency, super selectivity and easy to mass production material for Pb(Ⅱ) adsorption from solution.

中文翻译：

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新型吸附剂：天然金刚烷胺制备的纳米金刚烷/金刚烷复合物对Pb（Ⅱ）具有高吸附能力和超高选择性。

这项研究首先报道了一种新的纳米金刚烷/金刚烷复合物（NHLA复合物），该合成物是基于金刚烷胺与草酸的相互作用，通过一锅法直接从金刚烷胺制备的。通过X射线衍射确定由天然金刚烷形成的洪博定/金刚烷二元相。扫描和透射电镜分析表明，大量的具有均一尺寸（平均尺寸为15.59 nm）的纳米金刚烷被装载在铝金刚烷片上。与原始矿物相比，合成的复合材料对Pb（Ⅱ）的去除能力显着提高，表明去除Pb（Ⅱ）的主要活性成分是洪博定相而不是金刚烷胺本身。随着初始pH值或温度的升高，Pb（Ⅱ）的吸附容量增加。Langmuir等温线和伪二级动力学方程与实验结果吻合得很好，在25°C的温度下，Langmuir等温线的最大Pb（Ⅱ）吸附容量为574.71 mg / g。此外，在多种重金属离子共存体系中的重金属去除实验表明，该复合材料对Pb（Ⅱ）的吸附具有很高的选择性。离子交换，表面络合和静电相互作用都参与了Pb（Ⅱ）的吸附。该合成物被认为是一种低成本，高效率，高选择性，易于大规模生产从溶液中吸附Pb（Ⅱ）的材料。在多种重金属离子共存体系中进行重金属去除实验表明，该复合材料对Pb（Ⅱ）的吸附选择性高。离子交换，表面络合和静电相互作用都参与了Pb（Ⅱ）的吸附。该合成物被认为是一种低成本，高效率，高选择性，易于大规模生产从溶液中吸附Pb（Ⅱ）的材料。在多种重金属离子共存体系中进行重金属去除实验表明，该复合材料对Pb（Ⅱ）的吸附选择性高。离子交换，表面络合和静电相互作用都参与了Pb（Ⅱ）的吸附。该合成物被认为是一种低成本，高效率，高选择性，易于大规模生产从溶液中吸附Pb（Ⅱ）的材料。