Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM. Universidad Autónoma del Estado de México. Facultad de Química. Paseo Colón intersección Paseo Tollocan S/N. C.P. 50120, Toluca, Estado de México, Mexico.
J Hazard Mater. 2010 Apr 15;176(1-3):418-25. doi: 10.1016/j.jhazmat.2009.11.046. Epub 2009 Nov 13.
The electrochemical reduction of Cr(VI)-Cr(III) in wastewater by iron and copper-iron bimetallic plates was evaluated and optimized. Iron has been used as a reducing agent, but in this work a copper-iron galvanic system in the form of bimetallic plates is applied to reducing hexavalent chromium. The optimal pH (2) and ratio of copper to iron surface areas (3.5:1) were determined in batch studies, achieving a 100% reduction in about 25 min. The Cr(VI) reduction kinetics for the bimetallic system fit a first order mechanism with a correlation of 0.9935. Thermodynamic analysis shows that the Cr(VI) reduction is possible at any pH value. However, at pH values above 3.0 for iron and 5.5 for chromium insoluble species appear, indicating that the reaction will be hindered. Continuous column studies indicate that the bimetallic copper-iron galvanic system has a reduction capacity of 9.5890 mg Cr(VI) cm(-2) iron, whereas iron alone only has a capacity of 0.1269 mg Cr(VI) cm(-2). The bimetallic copper-iron galvanic system is much more effective in reducing hexavalent chromium than iron alone. The exhausted plates were analyzed by SEM, EDS, and XRD to determine the mechanism and the surface effects, especially surface fouling.
电化学还原废水中的六价铬-三价铬（Cr(VI)-Cr(III)），并对其进行评估和优化。铁一直被用作还原剂，但在这项工作中，以双金属板的形式应用铜-铁原电池系统来还原六价铬。通过批处理研究确定了最佳 pH 值（2）和铜铁表面积比（3.5:1），在约 25 分钟内实现了 100%的还原。双金属系统的 Cr(VI)还原动力学符合一级反应机制，相关系数为 0.9935。热力学分析表明，Cr(VI)还原在任何 pH 值下都是可行的。然而，在铁的 pH 值高于 3.0 和铬的 pH 值高于 5.5 时，会出现不溶性物质，表明反应将受到阻碍。连续柱研究表明，双金属铜-铁原电池系统的还原能力为 9.5890 mg Cr(VI) cm(-2)铁，而铁单独的还原能力仅为 0.1269 mg Cr(VI) cm(-2)。与单独的铁相比，双金属铜-铁原电池系统在还原六价铬方面更为有效。通过 SEM、EDS 和 XRD 分析失效的电极板，以确定反应机制和表面效应，特别是表面污垢。
