Department of Chemical Engineering, McMaster University, 1280, Main St. W., Hamilton, ON, Canada.
Yagar Technical Services, Canada.
Chemosphere. 2022 Jan;286(Pt 1):131600. doi: 10.1016/j.chemosphere.2021.131600. Epub 2021 Jul 19.
Mixed industrial wastewaters are often highly contaminated with heavy metals and organic pollutants. Treating these mixed wastewaters requires many stagewise unit operations. Our work investigates using an electrochemical oxidation-in-situ coagulation (ECO-IC) process as a pre-treatment step toward the efficient treatment of real mixed industrial wastewater rich with heavy metals and organic contaminants. The process degraded organic contaminants in the wastewater via anodic electrochemical oxidation. Simultaneously, heavy metals were precipitated in the solution by coagulants (iron hydroxides) formed in-situ by cathode-generated hydroxyl ions reacting with the significant amounts of dissolved iron in the wastewater. IrO-RuO mixed metal oxide anodes were identified as the best electrodes for organic compound degradation demonstrating 97% degradation of methyl orange (MO) as a model compound within 15 min. These anodes were used to treat real industrial wastewater produced from the industrial cleaning of train tanker cars transporting industrial solvents. The electrochemical treatment experiments resulted in a treated solution with a lower heavy metal content, achieving 96% reduction in Fe and 30% reduction in As content. Only moderate decreases in organic content were observed up to a maximum of 13% reduction in total organic carbon after 1 h of treatment. Electrochemical treatment of the mixed industrial wastewater produced greater effective diameter of the suspended particles and distinct sediment, liquid, and suspended foam phases that could be easily separated for further treatment. ECO-IC shows promise as an efficient and chemical-free method to coagulate heavy metals in real industrial wastewaters and could be an effective pre-treatment in their separation.
混合工业废水通常受到重金属和有机污染物的严重污染。处理这些混合废水需要许多分步的单元操作。我们的工作研究了将电化学氧化-原位混凝（ECO-IC）工艺作为预处理步骤，用于处理富含重金属和有机污染物的实际混合工业废水的有效方法。该工艺通过阳极电化学氧化降解废水中的有机污染物。同时，阴极产生的羟基离子与废水中大量溶解的铁反应，在溶液中形成铁氢氧化物等混凝剂，将重金属沉淀出来。IrO-RuO 混合金属氧化物阳极被确定为有机化合物降解的最佳电极，可在 15 分钟内将甲基橙（MO）等模型化合物降解 97%。这些阳极用于处理用于清洗运输工业溶剂的火车罐车的工业废水。电化学处理实验得到了重金属含量较低的处理溶液，Fe 的去除率达到 96%，As 的去除率达到 30%。处理 1 小时后，总有机碳的最大减少量仅为 13%，有机含量略有下降。电化学处理混合工业废水产生了更大的悬浮颗粒有效直径，明显的沉淀、液体和悬浮泡沫相，可以很容易地分离进行进一步处理。ECO-IC 作为一种在实际工业废水中有效且无需添加化学物质的混凝重金属的方法具有很大的应用前景，并且可以作为其分离的有效预处理方法。
