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| Synthesis of new-type TSADA and its remediation behavior for soil heavy metal pollution |
| Yang Lei, Fu Lijun, Shen Jinrui |
| Environment & Life Science Department, Putian University，351100, Putian,Fujian，China |
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Abstract In order to improve remediation ability of tea-saponin for heavy metal ions in the soil, the new-type green tea-saponin chelant(tea-saponin-1-amide-diethylenetriamine, TSADA) was prepared by tea saponin raw material extracted through aqueous extract-alcohol precipitation from tea seed cake. TSADA’s structure was studied by FT-IR, and its superficial performance was studied as well. Results showed that its critical micelle concentration was lower than the TS’s, but Hydrophile-lipophile Balance value and foaming and stable foam ability were higher than TS’s. Meanwhile the effect of some factors such as oscillation time, chelating agent concentration, pH and ionic strength on removal rate of heavy metal ions in contaminated soil by chelate was investigated. The results showed that the removal rate of heavy metal ions increased with oscillation time, chelating agent concentration increasing, reduced with ionic strength and pH increasing. The optimum technologies of removing Pb2+,Cd2+ ions by chelating agent were as follows: Oscillation time was 12h, chelating agent mass concentration was 7%, pH was 5.0, mole concentration of Ca(NO3)2 was 10mmol/L. Under the conditions, removal rate of Pb2+ and Cd2+ ions in the soil by two chelating agents both reached the maximum. Removal rate of Pb2+ and Cd2+ ions by TSADA was better than tea saponin’s respectively. The maximum removal rate of Pb2+ and Cd2+ ions by TSADA was 67.3% and 99.9% respectively.
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Received: 26 August 2011
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