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Comparison of several amendments for in-situ remediation of lead-and cadmium-contaminated farmland soil |
Received:May 07, 2018 Revised:July 09, 2018 |
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KeyWord:lead;cadmium;farm soil;remediation effectiveness;clay minerals;biochar |
Author Name | Affiliation | E-mail | WANG Jian-le | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China | | XIE Shi-bin | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China | | TU Guo-quan | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China | | FANG Zhan-qiang | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China Technical Innovation Alliance of Guangdong Environmental Restoration Industry, Guangzhou 510006, China | zhqfang@scnu.edu.cn |
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Abstract: |
Cost-efficiency of in-situ remediation of lead (Pb)- and cadmium (Cd)-contaminated farm soil using amended materials was assessed. The effects of ordinary diatomite (D), bentonite (BE), sepiolite (S), artificial zeolite (AZ), and hydroxyapatite (HA)were compared against those of biochar (B), diatomite/biochar (DB), bentonite/biochar (BEB), sepiolite/biochar (SB), artificial zeolite/biochar (AZB), and hydroxyapatite/biochar (HAB)on the immobilization of Pb- and Cd-contaminated farmland soil. After 21 d of remediation by these methods, experiments with diethylenetriaminepentaacetic acid (DTPA)showed that Pb and Cd bioaccessibilities decreased by 25.7%~83.4% and 8.4%~34.2% respectively. The order of Pb immobilization was found to be HA > D > AZ > BE > S > DB > BEB > AZB > SB > HAB > B, and the order of Cd immobilization was found to be SB > AZB > B > HAB > BEB > D > S > BE > AZ > HA > DB. Moreover, the sequential extraction procedure indicated that all of the above materials could increase the proportion of Pb and Cd residual states. HA, which is a clay mineral, had a distinct advantage in in-situ remediation of Pb-contaminated farmland soil, whereas the same was true for clay minerals and biochar with regard to the in-situ remediation of Cd-contaminated farmland soil. SB and AZB showed distinct advantages in the in-situ remediation of Pb- and Cd-contaminated farmland soil. After treatment, the farm soils'physical and chemical properties did not change significantly. |
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