改进硫化物沉淀法处理氨羧配位剂电镀镉废水的研究

摘要

Na2S-Al2 (SO4)3-PAM system is adopted to deal electroplating wastewater containing cadmium by ammonia complexing agent directly.The effects of initial pH value of wastewater,the dosage of Na2S,the dosage of Al2 (SO4)3 · 18H2O and reaction time on the treatment efficiency were studied.Experimental results show that at pH =7,when the dosage of Na2S is 5 mL/L,after stirring reaction 20 min at room temperature,8 mL/L Al2 (SO4)3 · 18H2O and 3 mL/L PAM were added,continue stirring reaction 5 min,and then put it aside for 15 min.The mass concentration of residual Cd2+ in the supernatant was 0.03 mg/L,which reaches the requirement of no more than 0.05 mg/L in GB 21900-2008,and the removal rate of Cd2+ reached 99.9 ％.%采用Na2S-Al2(SO4)3-PAM体系直接处理氨羧配位剂电镀镉废水,并考察了废水初始pH值、Na2S的投加量、Al2(SO4)3·18H2O的投加量及反应时间对处理效果的影响.结果表明:废水初始pH值为7、Na2S的投加量为5 mL/L,在常温下搅拌反应20 min;再投加絮凝剂Al2(SO4)3·18H2O8 mL/L及PAM 3 mL/L,继续搅拌反应5 min后静置15 min.上清液中残余Cd2+的质量浓度为0.03 mg/L,达到《电镀污染物排放标准》(GB 21900-2008)中规定的不大于0.05 mg/L的要求,同时Cd2+的去除率达到99.9％.