TMT类重金属捕集剂处理含Ni^(2+)电镀废水工艺研究

Treatment of Electroplating Wastewater Containing Ni^(2+)with TMT Heavy Metal Trap

电镀废水是重金属废水的重要来源。随着电镀废水排放标准日益严格,废水中的重金属的高效去除成为当前研究的热点。其中镍作为一类污染物,其排放指标更需严格把控。1,3,5-三嗪-2,4,6-三硫醇三钠盐(TMT)类重金属捕集剂,有着较强的螯合能力、较低的生物毒性以及较宽的环境使用条件等优点,逐步成为含Ni^(2+)电镀废水去除重金属离子的首先重金属捕集剂。本文通过研究TMT单组分重金属捕集剂及无机硫(硫化钠)以及络合物(硫代硫酸钠)不同比例组合,组成的复合型重金属捕集剂,对不同条件下含Ni^(2+)电镀废水去除重金属效果进行研究。最终筛选出,最佳重金属捕集剂配方及其最佳使用条件。结果:每100 mL废水,复合型重捕剂(质量分数5%)加入量为1~3 mL,聚合氯化铝(质量分数1%)加入量为2~4 mL,聚丙烯酰胺(质量分数0.02%)加入量为2~3 mL,pH值为10~11.5时,废水中Ni^(2+)的去除率可达到98%以上,经过处理的废水达到电镀污染物排放标准(GB 21900—2008)中表3标准。

Electroplating wastewater is an important source of heavy metal wastewater.With the increasingly strict discharge standard of electroplating wastewater,the efficient removal of heavy metals in wastewater has become a hot research topic.Among them,nickel is a kind of pollutant,and its emission indicators need to be strictly controlled.1,3,5-triazine-2,4,6-trimethanol trisodium salt(TMT)heavy metal collectors,with strong chelating capacity,low biological toxicity,and wide environmental use conditions,have gradually become the first heavy metal collectors to remove heavy metal ions from electroplating wastewater containing Ni^(2+).In this paper,the effect of heavy metal removal from electroplating wastewater containing Ni 2+under different conditions was studied by studying the composite heavy metal catcher composed of TMT single component heavy metal catcher,inorganic sulfur(sodium sulfide)and complex(sodium thiosulfate)in different proportions.Finally,the best heavy metal catcher formula and its best use conditions were screened out.Results:For every 100 mL of wastewater,the addition amount of composite heavy catcher is 1~3 mL(5%),the addition amount of polyaluminum chloride(1%)is 2~4 mL,and the addition amount of polyacrylamide(0.02%)is 2~3 mL.When the pH value is 10~11.5,the removal rate of Ni^(2+)in wastewater can reach more than 98%,and the treated wastewater can meet the standard in Table 3 of the Discharge Standard of Electroplating Pollutants(GB 21900—2008).