소석회, 포틀랜드 시멘트, FeCl3·6H2O, NaOH를 이용한 비소 오염토양의 안정화

Abstract

The purpose of this study was to investigate the effectiveness of a stabilization treatment for As contaminated soil. A combination of hydrated lime, Portland cement, , and NaOH were used as stabilizing agents. The effectiveness of stabilization treatment was evaluated by the Korean Standard Test (KST) method (1N HCl extraction). Sequential extractions were performed to investigate the As distribution after treatment. Following the application of the treatment, curing periods of up to 7 and 28days were investigated. The experimental results showed that a combination of hydrated lime/Portland cement was more effective than treatments of hydrated lime or Portland cement at immobilizing As in the contaminated soil. The treatment of 25wt% hydrated lime and 5wt% Portland cement was effective in reducing As leachability less than the Korean warning standard of 20 mg/kg. However, the treatments of hydrated lime and Portland cement failed to meet the Korean warning standard even when up to 30 wt% was used. The treatment utilizing hydrated lime and was not effective in properly reducing As leachability. The addition of was negative in terms of pH condition. Moreover, the treatment with hydrated lime/NaOH was effective in reducing As leachability but not as much as hydrated lime/Portland cement. The sequential extraction results indicated that the residual phase was greatly increased upon the treatment of hydrated lime/Portland cement. It was concluded that the hydrated lime/Portland cement treatment was the best among the other combinations studied at achieving trace As concentrations.