实验室重金属废水处理研究

根据实验室废水中Hg2+和Cr3污染特点,以硫酸亚铁、硫化钠作为还原剂,将废水中的Cr6+还原为Cr3+,Hg2+和Cr3+以沉淀的形式混凝去除。分别考察pH值、反应时间及还原剂投加量对两种重金属去除率的影响,结果表明过低的反应时间不利于Cr6+和Hg2+的去除,pH2.0时,Cr6+和Hg2+的还原效率较高,FeSO4和Na2S加量分别在1 000 mg/L和667 mg/L时,Cr6+和Hg2+具有较高的去除效率。利用正交实验对污染物去除条件进行优化,结果表明,两种无机还原剂投加比例对铬、汞两种重金属离子的去除率影响大,pH值次之,反应时间对去除率的影响最小,在pH为2.0、FeSO4和Na2S加量分别在1 000 mg/L和667 mg/L,反应时间为30 min时,废水中Hg2+和Cr6+的去除率最高,分别达到98.23%、95.97%,处理后废水达到国家污水排放标准。

Study on Treatment of Heavy Metal Sewage from Labs

According to characteristics of Hg2＋ and Cr3＋ in lab wastewater, the study researches on the process to restore Cr6 ＋ to Cr3＋ using FeSO4 and Na2 S as a reducing agent, and then removed in the form of coagulation with Hg2＋ . The influence of pH, reaction time, and dosage were investigated. The results show that adequate time is conducive to Cr6＋ and Hg2＋ removal,＋ and when pH 〈 2. 0, there was the high removed efficiency for Cr6＋ and Hg . FeSO4 and NazS, respectively, in 1 000 mg/L and 667 mg/L time, there was a high removal efficiency for Cr＋6 and Hg2＋. Treatment conditions were optimized by orthogonal experimental for the removal of pollutants, and the results showed that the proportion of both inorganic chromium reducing agent dosing was more important for the removal of heavy metal, when pH was 2. 0, FeSO4 and Na2S was 1 000 mg/L and 667 mg/L re- spectively, and reaction time was 30 min, the wastewater Hg2＋ and Cr6＋ removal highest, respectively, 98.23% , 95.97%, trea- ted wastewater meet national effluent standards.