In this study, soil washing is applied for the remediation of heavy-metal (Pb, Cu and Zn) contaminated paddy soil located near an abandoned mine area. FeCl₃ washing solutions were used in bench-scale soil washing experiments at concentrations in the range of 0.1 to 1 M. The strong acid, HCl was also used in this study for comparison. The washing process was performed at room temperature, mixing at 200 RPM for 1 h and a liquid to solid ratio of 2. A sequential extraction technique was performed to evaluate the chemical fractions of Pb in the soils. The soil washing effectiveness was evaluated and compared against regulations applicable to residential districts (Korean warning standards). The soil washing results showed that the heavy metal concentrations were reduced with increasing concentrations of FeCl₃. Moreover, the lowest heavy metal concentrations were obtained with a 1 M FeCl₃ washing solution. In the case of Pb removal, a 0.3 M FeCl₃ washing solution was required to comply with the Korean warning standard of 200 mg/kg. The lowest Pb concentration of 117 mg/kg was obtained with 1 M FeCl₃. Similar washing results were also obtained with HCl. The initial total concentrations for Cu and Zn were below the Korean warning standards of 150 and 300 mg/kg, respectively. Consequently, the reduction in Cu and Zn from the contaminated paddy soil using FeCl₃ washing solutions was rather limited. The sequential extraction results showed that the exchangeable and weak acid-soluble fractions of Pb were significantly reduced upon FeCl₃ washing.

在这项研究中，土壤清洗用于修复位于废弃矿区附近的重金属（Pb、Cu 和 Zn）污染的稻田土壤。FeCl ₃洗涤液用于实验室规模的土壤洗涤实验，浓度范围为 0.1 到 1 M。强酸 HCl 也用于本研究进行比较。洗涤过程在室温下进行，以 200 RPM 的速度混合 1 小时，液固比为 2。采用连续提取技术评估土壤中 Pb 的化学成分。对土壤清洗效果进行了评估，并与适用于住宅区的法规（韩国警告标准）进行了比较。土壤冲洗结果表明，重金属浓度随着 FeCl 浓度的增加而降低₃ . 此外，使用 1 M FeCl ₃洗涤溶液获得最低的重金属浓度。在去除 Pb 的情况下，需要 0.3 M FeCl ₃洗涤液以符合韩国 200 mg/kg 的警告标准。使用 1 M FeCl ₃获得了 117 mg/kg 的最低 Pb 浓度。用 HCl 也获得了类似的洗涤结果。Cu 和 Zn 的初始总浓度分别低于韩国警告标准 150 和 300 mg/kg。因此，使用 FeCl ₃减少受污染稻田中的 Cu 和 Zn洗涤液相当有限。连续萃取结果表明，FeCl ₃洗涤后，Pb 的可交换组分和弱酸溶组分显着减少。