Recycling treatment of wastewater containing hexavalent chromium [Cr (VI)] has always been an important environmental issue. In this paper, taking advantage of the natural affinity of CrO₄²⁻ and lead ions, lead carbonate was selected as a precipitant to recover Cr (VI) in the form of chrome yellow (PbCrO₄). Firstly, the variation of Cr (VI) and lead species in K⁺-CrO₄²⁻-Pb²⁺-CO₃²⁻ solution system with pH and PbCO₃ dosage was calculated by Visual MINTEQ. The results show that the treatment effect is better under acidic conditions. Then, the effects of parameters on the removal rate of Cr, including the initial pH of solution, reaction time, reaction temperature, and the dosage of lead carbonate, were studied by batch experiments. Results show that the initial pH of solution, reaction time, and the dosage of lead carbonate have great influence, whereas reaction temperature has slight influence. And the concentration of Cr (VI) could be reduced from 100 mg/L to 0.043 mg/L at an initial pH of 3, a reaction time of 45 min, and the dosage of lead carbonate as n(PbCO₃)/n(K₂CrO₄) = 2. The precipitates are analyzed by XRD, SEM, and EDS，and the results are consistent with the predictions of Visual MINTEQ, that is, the newly produced substance is only PbCrO₄. The reaction mechanism of Cr (VI) on the surface of lead carbonate was studied by the adsorption kinetic model, and the results showed that the reaction was more fit with the pseudo-second-order kinetic model. Density functional theory (DFT) calculations show that CrO₄²⁻ could effectively react with lead atoms with unsaturated coordination bonds on the surface of lead carbonate and free lead ions leached from the surface of lead carbonate to form lead chromate. Under acidic conditions, the removal of Cr (VI) by PbCO₃ may involve two main mechanisms: the mineralization and precipitation of lead and chromate ions dissolved from the surface of cerussite and the chemical adsorption of chromate ions on the surface of cerussite. This study provides a new and efficient strategy for the resource treatment of Cr (VI)-containing wastewater.

含六价铬[Cr(VI)]废水的循环处理一直是一个重要的环境问题。在本文中，利用CrO ₄ ^{2 -}和铅离子的天然亲和力，选择碳酸铅作为沉淀剂以铬黄（PbCrO ₄ ）的形式回收Cr（VI ）。首先，K ⁺ -CrO ₄ ^{2 -} -Pb ²⁺ -CO ₃ ^{2 -}溶液体系中 Cr (VI) 和铅的形态随 pH 值和 PbCO _{3的变化而变化}剂量由 Visual MINTEQ 计算。结果表明，酸性条件下处理效果较好。然后，通过批量实验研究了溶液初始pH、反应时间、反应温度、碳酸铅用量等参数对Cr去除率的影响。结果表明，溶液初始pH值、反应时间、碳酸铅用量影响较大，反应温度影响较小。在初始pH为3、反应时间为45 min、碳酸铅用量为n(PbCO ₃ )/n( K ₂ CrO ₄ ) = 2。通过XRD分析析出物，SEM、EDS，结果与Visual MINTEQ的预测一致，即新生成的物质仅为PbCrO ₄ 。采用吸附动力学模型研究了Cr(VI)在碳酸铅表面的反应机理，结果表明该反应更符合准二级动力学模型。密度泛函理论（DFT）计算表明，CrO ₄ ^{2 -}可以有效地与碳酸铅表面具有不饱和配位键的铅原子和从碳酸铅表面浸出的游离铅离子反应形成铬酸铅。_{在酸性条件下，PbCO 3}去除 Cr(VI)可能涉及两个主要机制：铅和铬酸根离子从白铅矿表面溶解的矿化和沉淀，以及铬酸根离子在白铅矿表面的化学吸附。本研究为含Cr(VI)废水的资源化处理提供了一种新的有效策略。