School of Resources & Environmental Engineering, Wuhan University of Technology, 430070, Wuhan, China.
School of Resources & Environmental Engineering, Wuhan University of Technology, 430070, Wuhan, China.
Chemosphere. 2020 Jun;249:126227. doi: 10.1016/j.chemosphere.2020.126227. Epub 2020 Feb 14.
Efficient lead removal from metal-containing wastewater, such as acid mine drainage (AMD), is an important step in environmental purification and secondary resources recovery. In this paper, a novel approach by mechanochemically activating CaCO through simply wet ball milling in metal-containing solution was developed, where selective Pb precipitation in the form of PbCO was achieved based on its reaction with the CO from the activated CaCO. By such milling operation, the removal efficiency of Pb from aqueous solution could reach over 99%, while more than 99% Zn (as well as Mn, Ni and Cd) was remaining in the solutions, demonstrating the feasibility and high effectiveness of precipitating Pb and serving the purpose of recovering other metals without Pb impurity. The solubility differences between Pb carbonate and other carbonates of Zn, Mn, Ni or Cd were understood to be the main pathway and using CaCO would offer an easy operation and environmental friendly process to purify the metals-containing wastewater by precipitating Pb, compared with the difficulties when using alkaline neutralization to treat them. In addition, basic zinc carbonate (a zinc-containing ore waste) as an alternative precipitant to CaCO in the separation process was also confirmed to increase the zinc recovery in the solution while maintaining high Pb removal efficiency.
从含金属废水中（如酸性矿山排水，AMD）高效去除铅是环境净化和二次资源回收的重要步骤。本文提出了一种通过在含金属溶液中简单湿球磨机械化学激活碳酸钙的新方法，其中通过与来自激活碳酸钙的 CO 反应，以 PbCO 的形式实现了 Pb 的选择性沉淀。通过这种研磨操作，水溶液中 Pb 的去除效率可达到 99%以上，而超过 99%的 Zn（以及 Mn、Ni 和 Cd）仍留在溶液中，证明了沉淀 Pb 的可行性和高效性，同时可以回收其他不含 Pb 杂质的金属。理解 Pb 碳酸盐与 Zn、Mn、Ni 或 Cd 的其他碳酸盐之间的溶解度差异是主要途径，与使用碱性中和处理相比，使用 CaCO3 通过沉淀 Pb 来净化含金属废水的操作更容易且对环境更友好。此外，在分离过程中，还确认使用碱性碳酸锌（一种含锌矿石废料）作为 CaCO3 的替代沉淀剂，在保持高 Pb 去除效率的同时，还可以提高溶液中锌的回收率。
