电催化氧化-化学沉淀耦合工艺处理化学镀镍废水

采用电催化氧化-化学沉淀耦合工艺处理化学镀镍废水。正交实验结果表明,电催化氧化优化条件为:槽电压17.5 V,初始pH为7,NaCl投加量为17 g/L,反应时间为90 min;单因素实验结果表明化学沉淀优化条件:不用调节pH,以CaO为沉淀剂,CaO投加量为3 g/L,反应时间30 min。在此工艺条件下,COD、镍离子、总磷去除率分别为94.48%、99.89%、99.96%,最终出水COD为43 mg/L,镍离子质量浓度为0.08 mg/L,总磷质量浓度为0.24 mg/L,可达到《电镀污染物综合排放标准》(GB 21900—2008)表3中水污染物特别排放限值的要求。

Study on the electrocatalytic oxidation-chemical precipitation coupled process for the advanced treatment of electroless nickel-plating wastewater

The electrocatalytic oxidation-chemical precipitation coupled process has been used for treating electro-less nickel-plating wastewater. The orthogonal test analyses show that the optimum conditions of electrocatalytic oxi-dation are as follows:the cell voltage is 17.5 V,initial pH is 7,NaCl dosage 17 g/L,and reaction time 90 min. The single-factor experiments show that the optimum conditions of chemical precipitation reactions are as follows:without using pH adjustment;while CaO is used as precipitant,the optimum CaO dosage is 3 g/L,and the reaction time 30 min. Under the above operation conditions,the removing rates of COD,nickel ions and total phosphorus could reach 94.48%,99.89%,and 99.96%,respectively,and the final effluent COD is 43 mg/L,mass concentration of nickel ions 0.08 mg/L,and mass concentration of total phosphorus 0.24 mg/L,achieving the special discharge limit values of water pollutants specified in Table 3 of the Comprehensive Discharge Standard for Pollutants from Electroplating (GB 21900—2008).