出版社：Korean Society of Environmental Health and Toxicology
摘要：Heavy metals produced by metal plating industries have long been a nuisance because of their potential adverse effect. Among possible treatment processes,many of the metal plating industries often imploy oxidation-reduction technique due to the cost problem is involved. When cyanide and hexavalent chromium are present in waste-water,however,the process may be complexed and ineffective. In this study,a commercially developed precipitant was applied to the removal of heavy metals and the optimum process condition was investigated using several operating parameters such as pH,precipitant and sodium sulfide dosages. The precipitant,which consists of ferrous sulfate,tannic acid,and chelating agent has advantages over conventional precipitants. Cyanide and hexavalent chromium can be removed along with other heavy metals without their reduction. The precipitation of heavy metals cannot be re-extracted. The analysis of supernatant after the precipitation of heavy metals showed that ion concentrations of heavy metals were under regulatory limit at optimum operating condition. The observed condition was pH of about 8,the precipitant and sodium sulfide dosage of 20,000ppm and 0.7g/l respectively. However,sufficient removal of unprecipitated cyanide was reached after using ion exchange process as metal complexes.
