印刷电路板含铜配离子复杂废水脱铜研究

Decoppering of copper-complexing wastewater from printed circuit boards

应用有关热力学数据,对Cu2+-EDTA-S2-H2O系的热力学行为进行研究,并对印刷电路板含铜配离子复杂废水的处理进行实验研究。研究结果表明:采用中和沉淀法处理含铜配离子废水难以达到国家电镀污染物排放标准(GB21900—2008),通过添加硫化物可以破坏离子的配合平衡,使铜以硫化物形式沉淀;硫化沉淀法处理印刷电路板废水的最佳工艺参数如下:用Ca(OH)2将pH值调到12.5,反应温度为25℃,水解时间为30min,n(Na2S):n(Cu)=1:1,硫化沉淀时间50min,PAM质量浓度为6mg/L,残余Cu2+质量浓度低于0.2mg/L。在此最佳工艺参数下,实验结果与理论分析结果相吻合。

The thermodynamics behavior of Cu2＋-EDTA-S2-H2O system was studied by means of calculating the thermodynamic data. The experimental study of treating the printed circuit boards wastewater with sulfide precipitation method was conducted. The results show that the content of copper-complexes in wastewater treated with the simple neutralization precipitation fails to attain the Emission Standard of Pollutants for Electroplating （GB 21900—2008）. However, sulfide precipitation method can be used to remove Cu as sulfide precipitate since the coordination equilibrium is destroyed. The optimal technical parameters are as follows： pH value is 12.5, the temperature is 25 ℃, hydrolyzed time is 30 min, n（Na2S）：n（Cu）=1：1, sulfide precipitation time is 50 min, PAM mass concentration is 6 mg/L, and the residual Cu2＋ concentration in treated water is lower than 0.2 mg/L. In the optimal condition, the experimental results are consistent with the theoretic results.