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| Optimization of Technological Conditions for Remediation of Heavy Metal Contaminated Soil by Rhamnolipid Washing |
| Received:March 01, 2015 |
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| KeyWord:soil;heavy metals;rhamnolipid;soil washing;speciation;technological conditions |
| Author Name | Affiliation | E-mail | | LI You | Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China
University of Chinese Academy of Science, Beijing 100049, China | | | LIAO Xiao-yong | Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China | liaoxy@igsnrr.ac.cn | | YAN Xiu-lan | Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China | | | GONG Xue-gang | Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China
University of Chinese Academy of Science, Beijing 100049, China | |
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| Abstract: |
| Rhamnolipid biosurfactant has showed to be effective in removing heavy metals from soils. Here a study was initiated to optimize pH, temperature and washing time for removal of heavy metals and arsenic by rhamnolipid from contaminated soil collected from a smeltery in Hunan. At solution pH 2, the extraction of Zn, Cd, and As was the greatest, which was 397, 30, and 21 mg·kg-1, respectively. However, the washing rates of Cu increased with increasing pH values. At the temperature of 40 ℃, the maximum elution for Cd, Zn, Cu, and As was obtained, which was 36, 438, 33, and 29 mg·kg-1, respectively, whereas the highest leaching concentration of Pb(54 mg·kg-1) was obtained at 30 ℃. Three successive washing cycles with the mixture solutions of rahmnolipid and HCl were shown to remove 23.10% of Pb, 53.78% of Cd, 44.74% of Zn, 63.19% of Cu, and 34.37% of As. Successive washing resulted in significant declines in acid extractable, oxides bound and organic bound heavy metals, while in residual and oxides bound arsenic. The present results could provide a technical guidance for remediation of heavy metal contaminated soils by rhamnolipid washing. |
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