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| Remediation of Soils Co-contaminated with Cd-Zn and Cd-Ni by Washing with Oranic Acids |
| Received:January 22, 2015 |
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| KeyWord:heavy metals;soil washing;tartaric acid;ultrasonic wave |
| Author Name | Affiliation | E-mail | | WU Jian | School of Environmental and Energy, South China University of Technology, China
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education
Engineering and Technology Research Centre of Guangzhou Water Resource and Water Environment, Guangzhou 510006, China | | | PAN Wei-bin | School of Environmental and Energy, South China University of Technology, China
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education
Engineering and Technology Research Centre of Guangzhou Water Resource and Water Environment, Guangzhou 510006, China | ppwbpan@scut.edu.cn | | LIN Rui-cong | School of Environmental and Energy, South China University of Technology, China
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education
Engineering and Technology Research Centre of Guangzhou Water Resource and Water Environment, Guangzhou 510006, China | | | LAI Cai-xiu | School of Environmental and Energy, South China University of Technology, China
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education
Engineering and Technology Research Centre of Guangzhou Water Resource and Water Environment, Guangzhou 510006, China | | | ZHAN Shu-wei | School of Environmental and Energy, South China University of Technology, China
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education
Engineering and Technology Research Centre of Guangzhou Water Resource and Water Environment, Guangzhou 510006, China | |
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| Abstract: |
| Soil flushing is one of remediation techniques for metals contaminated soils. Here an effective soil washing process was studied in two metal-contaminated sites, namely soil A, which was polluted by Cd and Zn, and soil B, which was polluted by Cd and Ni. A two-step washing method using oxalic acid combined with four different acids, such as acetic acid, citric acid, tartaric acid and succinic acid, was evaluated in terms of removal of bioavailable portion of heavy metals. In addition, soil washing with citric acid or tartaric acid alone was conducted. Enhancing effect of ultrasonic wave on metal washing by tartaric acid was also investigated. Results showed that the removal efficiencies of two-step washing process using citric acid or tartaric acid(0.1 mol·L-1, for 16 h) and oxalic acid(0.2 mol·L-1, for 16 h) sequentially were the highest. Under tartaric acid alone(0.1 mol·L-1, t=2 h), the removal of Cd, Zn and Ca was respectively 30.74%, 25.59%, and 15.86% for soil A, while that of Cd, Ni and Ca was respectively 47.36%, 6.89%, and 23.92% for soil B. Tartaric acid was an efficient washing agent with high heavy metals removal capacity but low Ca leaching. The introduction of ultrasonic wave enhanced the removal efficiencies of heavy metals in tartaric acid washing system, which shortened the washing time from 2 h to 30 min. The findings show that it is possible to develop an environmentally friendly soil washing technique for heavy metals contaminated soils. |
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