Pedosphere 22(1): 131--136, 2012
ISSN 1002-0160/CN 32-1315/P
©2012 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Chromium extraction from sewage sludge using polyepoxysuccinic acid |
ZHANG Li-Hua1 and ZHU Zhi-Liang2 |
1 Department of Chemistry and Biology Engineering, Sanming University, Sanming 365004 (China)
2 State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China) |
| ABSTRACT |
| An environmentally benign biodegradable chelant,polyepoxysuccinic acid (PESA),was used to separate heavy metals from sewage sludge from the Shanghai Taopu Wastewater Treatment Plant,China,based on chemical extraction technology.The extraction of chromium (Cr) from sewage sludge with an aqueous solution of PESA was studied under various conditions.It was found that the extraction of Cr using PESA was more efficient than that using ethylenediaminetetraacetic acid (EDTA) and S,S-ethylenediaminedisuccinic acid (EDDS) under similar conditions.PESA was capable of extracting Cr from the sewage sludge,and the extraction efficiency was obviously dependent on both the pH and the concentration of the chelating reagent.The extraction efficiency decreased gradually with increasing pH,and the dependence on pH decreased as the concentration of PESA increased.The extraction efficiency reached 58% under conditions of pH = 4 and a ratio of PESA to total heavy metals of 10:1.The extraction efficiency was maintained above 40% within the pH range from 1 to 7 at the high ratio of PESA to total heavy metals of 10:1.Comparing the contents of heavy metals in the sewage sludge before and after the extraction,it was found that the extracted Cr came mainly from the reducible and oxidizable fractions. |
| Key Words: ethylenediaminetetraacetic acid, extraction efficiency, heavy metals, pH, S,S-ethylenediaminedisuccinic acid |
| Citation: Zhang, L. H. and Zhu, Z. L. 2012. Chromium extraction from sewage sludge using polyepoxysuccinic acid. Pedosphere. 22(1): 131-136. |
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