This study aimed to evaluate the possibility of using iron filling from machine shops as a low- cost reactive medium for treating groundwater contaminated by trichloroethylene (TCE) and czs-1,2-dichloroethylene (cis-DCE) The efficiency of reductive dechlorination of trichioroethylene and czs-1,2-dichloroethylene (cis-DCE) by iron filling were further studied in different concentrations at pH 5. The initial TCE and cis-DCE concentrations ranged from 1 to 1000 mg/L. The results showed that the degradation rates of these contaminants were rapid at low concentration and relatively slow at high concentration. At day 7, the removal was 100% with the initial TCE concentrations of 1 and 10 mg/L and with the initial DCE concentrations of 1, 10, 25, 50 and 100 mg/L. The observed pseudo-first order rate constants for TCE and DCE degradations were 0.29 to 0.94 day and 0.33 to 1.39 day1, respectively. The result showed that the rate constant of cis-DCE was higher than TCE. The major products in the dechlorination of TCE were ethylene and chloride The concentrations of cis-DCE and vinyl chloride (VC) were detected in small amounts in the reductive dechlorination of TCE at day 7. In addition, with the high concentration of initial cis-DCE and TCE of 1000 mg/L, the VC accumulated in the system with concentration of 28.0 and 3.47 mg/L found at day 7, respectively The increase of chloride in the aqueous solution indicated that the degradation of contaminants was the result of its reductive dechlorination which occurred by transferring electrons from the surface of metallic iron to the contaminants. These results elucidated that Iron fillings from machine shops could served as an alternative reactive medium for the remediation of groundwater contaminated with chlorinated contaminants.
2008 International Conference on Environmental Quality Concern,Control and Conservation，起迄日：2008/5/23~2008/5/24，地點：Chia Nan University of pharmacy and Science