羟基乙叉二膦酸镀铜废液的处理及Cu~(2+)的高附加值资源化回收

采用Na BH4还原法将羟基乙叉二膦酸(HEDP)镀铜废液中的Cu~(2+)制备成纳米铜粉,并采用聚丙烯酰胺(PAM)对还原反应后的废液进行絮凝处理。研究了n(Cu~(2+))∶n(Na BH4)、还原反应温度、还原反应时间及PAM添加量对废液中剩余Cu~(2+)质量浓度的影响,并对回收的纳米铜粉进行了XRD和TEM表征。实验结果表明:当n(Cu~(2+))∶n(Na BH4)=4∶6、还原反应温度为50℃、还原反应时间为2 h时,废液中剩余Cu~(2+)质量浓度降低至1.1 mg/L,Cu~(2+)还原率达99.99%;可获得粒径为20~45 nm的近球型、高纯度、由多晶组成的纳米铜粉;当PAM添加量为10 mg/L时,废液中剩余Cu~(2+)质量浓度降至0.35 mg/L以下,达到GB 21900—2008《电镀污染物排放标准》(小于0.5 mg/L)的要求。

Treatment of HEDP copper plating effluent and recovery of Cu2+ with high added value

Cu²⁺ was recoved from the HEDP copper plating effluent by NaBH₄ reduction method to prepare copper nanoparticle. The wastewater after reduction reaction was further treated by polyacrylamide（PAM）flocculant. The effects of n（Cu²⁺）:n（NaBH₄）,reduction reaction temperature,reduction reaction time and PAM amount on the residual Cu²⁺mass concentration of the wastewater was studied,and the prepared copper nanoparticles were characterized by XRD and TEM. The experimental results showed that：Under the conditions of n（Cu²⁺）:n（NaBH₄）= 4:6,reduction reaction temperature 50 ℃ and reduction reaction time 2 h,the residual Cu²⁺ mass concentration of the wastewater was dropped below 1.1 mg/L,the Cu²⁺ reduction rate was 99.99%;The obtained copper nanoparticles were high-purity spheroidal powders with 20-45 nm of size and consisted of polycrystals;When the PAM addition was 10 mg/L,the residual Cu²⁺ mass concentration of the wastewater was decreased to below 0.35 mg/L,which met the national discharge standard of GB 21900-2008（less than 0.5 mg/L）.