1. School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050081,China ;2. Hebei Yu huan Environmental Technology Corporation Ltd., Shijiazhuang 050010,China
The chromium contaminated soil in the Da Tong Chemical Corporation Ltd. was used as the research object, the removal effects for hexavalent chromium and total chromium in chromium contaminated soil of six kinds of leaching agent were studied to select the optimum leaching agent. Through orthogonal experiment, the optimum leaching conditions of the optimum leaching agent were determined. And the removal effects for hexavalent chromium and total chromium in chromium contaminated soil of complex leaching agents were also investigated. Ultimately the optimum washing times of the optimum leaching agent were determined. The results show that citric acid has the highest leaching removal efficiency of hexavalent chromium and total chromium,and the optimum leaching conditions of citric acid were 0.5 mol/L of citric acid concentration, 4 h of washing time, 2.0 of pH value, and 1∶10 of the solid-liquid ratio under which the removal rate of hexavalent chromium and total chromium reach 100% and 93.03% after 4 times washing, respectively. And the total chromium concentration in soil reduces from 2 630 mg/kg to 183.4 mg/kg, which can meet the secondary standard of site remediation requirements of "Soil Environmental Quality Standards".
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