School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
School of Life Sciences, Central South University, Changsha 410083, China.
Chemosphere. 2021 Jan;263:127833. doi: 10.1016/j.chemosphere.2020.127833. Epub 2020 Aug 15.
Comprehensive utilization of tailings is not only conducive to ensuring the sustainable use of resources but also can reduce the related environmental pollution. In the present work, a new utilization way of copper tailings was proposed and a novel composite (OMT-6) was prepared by modification of tailings with oxalic acid. The composite had super high Pb adsorption capacity with the maximal Pb removal capacity of 862.07 mg/g. Its Pb removal behaviours followed pseudo-second-order kinetic equation and Langmuir model, suggesting that Pb removal depended on monolayer adsorption. The surface of OMT-6 was rough and a lot of nanospheres were loaded on its surface. The composite had mesoporous structure and a larger specific surface area compared with tailings, the above characteristics of which facilitated Pb removal. The major crystal structures of OMT-6 were transformed to CaCO•HO and FeCO•2HO after oxalic acid modification and Pb could be removed by the ions exchange between Ca, Fe and Pb. Pb removal mechanisms of OMT-6 involved ion exchange, surface complexation and electrostatic attraction interaction, among which ion exchange played a key role. These results indicated that the prepared OMT-6 composite from copper tailings was an ideal material for Pb removal from aqueous solution.
尾矿的综合利用不仅有利于保障资源的可持续利用，还可以减少相关的环境污染。在本工作中，提出了一种利用铜尾矿的新方法，即用草酸对尾矿进行改性制备了一种新型复合材料（OMT-6）。该复合材料对 Pb 的吸附容量极高，最大 Pb 去除容量为 862.07mg/g。其 Pb 去除行为遵循准二级动力学方程和 Langmuir 模型，表明 Pb 的去除取决于单层吸附。OMT-6 的表面粗糙，表面负载了大量纳米球。与尾矿相比，该复合材料具有介孔结构和更大的比表面积，这些特性有利于 Pb 的去除。OMT-6 的主要晶体结构在草酸改性后转化为 CaCO•HO 和 FeCO•2HO，Pb 可以通过 Ca、Fe 和 Pb 之间的离子交换去除。OMT-6 的 Pb 去除机制涉及离子交换、表面络合和静电吸引相互作用，其中离子交换起着关键作用。这些结果表明，由铜尾矿制备的 OMT-6 复合材料是一种从水溶液中去除 Pb 的理想材料。
