碳酸钙改性硅藻土处理电解锌漂洗废水实验研究

铅锌矿在我国储存量大,电解法生产锌过程中可产生含Zn~(2+)、Pb~(2+)、Cd~(2+)、As5+和Cu~(2+)等重金属离子的漂洗废水。以硅藻土精土为基体,用碳酸钙作为改性剂制备改性硅藻土,对电解锌漂洗废水进行吸附实验研究。结果表明:在反应时间为150 min,碳酸钙改性硅藻土用量为3 g/L,pH为5.46,温度为25℃条件下,对废水进行吸附实验,吸附后废水中的Cu~(2+)和As5+离子浓度低于仪器检测线(0.01 mg/L和0.09 mg/L),Pb~(2+)浓度为0.16 mg/L,吸附后废水中Cu~(2+)、As5+和Pb~(2+)离子浓度均满足GB 25466—2010《铅锌工业污染物排放标准》的排放要求。同时,采用SEM、FTIR、XRD等对碳酸钙改性硅藻土进行表征,进一步探讨了碳酸钙改性硅藻土对重金属的吸附机理。

EXPERIMENTAL STUDY ON THE TREATMENT OF ELECTROLYTIC ZINC RINSING WASTEWATER BY USING CALCIUM CARBONATE MODIFIED DIATOMITE

The reserves of lead and zinc deposits is large in China.The rinsing wastewater produced in the electrolytic process for the production of zinc contained Zn2+,Pb2+,Cd2+,As5+,Cu2+ and other heavy metal ions.Modified diatomite was prepared by calcium carbonate based on pure diatomite,and was used to the experimental study on the adsorption.The optimum conditions of adsorption were that the calcium carbonate modified diatomite dosage was 3 g/L,the reaction time was 150 min,the pH was 5.46,and the temperature was 25 ℃.Under the optimum conditions,the concentration of Cu2+ and As5 + were under detection line (0.01,0.09 mg/L).The concentrationof Pb2 + was 0.16 mg/L,and all the concentration was lower than the "Emission Standard of Pollutants for Lead and Zinc Industry" (GB 25466-2010).The modified diatomite was characterized by SEM,XRD,and FT-IR.The adsorption mechanism of calcium carbonate modified diatomite on heavy metals was further investigated.