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Open AccessArticle

Comparative Activation Process of Pb, Cd and Tl Using Chelating Agents from Contaminated Red Soils

by Lirong Liu 1, Dinggui Luo 1,2,3,4,*, Guangchao Yao 1, Xuexia Huang 1,2,3,4, Lezhang Wei 1,2,3, Yu Liu 1,2,3, Qihang Wu 3,4, Xiaotao Mai 1, Guowei Liu 1 and Tangfu Xiao 1
1
School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
2
Linköping University—Guangzhou University Research Center on Urban Sustainable Development, Guangzhou University, Guangzhou 510006, China
3
Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China
4
Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, Guangzhou University, Guangzhou 510006, China
*
Author to whom correspondence should be addressed.
Int. J. Environ. Res. Public Health 2020, 17(2), 497; https://doi.org/10.3390/ijerph17020497
Received: 14 December 2019 / Revised: 7 January 2020 / Accepted: 8 January 2020 / Published: 13 January 2020
(This article belongs to the Section Environmental Remediation and Management)
Adding chelating agents is a critical technique of heavy metal activation for enhancing phytoextraction through the formation of soluble metal complexes which will be more readily available for extraction. The preliminary, dynamic, equilibrium activation experiments and speciation analysis of Pb, Cd and Tl in contaminated red soils were used to select six chelates with relatively good activation performance from nine chelates, and the effects of dosage and pH on the heavy metals activation were studied systematically. Results showed that the activation of Pb, Cd and Tl by chelates reached equilibrium within 2 h, and the activation process showed three stages. Under neutral conditions, chelates had better activation performance on Pb- and Cd-contaminated soils. Except for S,S-ethylenediamine disuccinic acid (S,S-EDDS) and citric acid (CA), the maximum equilibrium activation effect (MEAE) of ethylenediaminetetraacetic acid (EDTA), N,N-bis (carboxymethyl) glutamic acid (GLDA), diethylenetriaminepentaacetic acid (DTPA) and aminotriacetic acid (NTA) was over 81%. The MEAE of Tl-contaminated soil was less than 15%. The decreasing order of the dosage of chelating agents corresponding to MEAE for three types of contaminated soils was Pb-, Cd- and Tl-contaminated soil, relating to the forms of heavy metals, the stability constants of metal–chelates and the activation of non-target elements Fe in red soil. Under acidic conditions, the activation efficiencies of chelates decreased to differing degrees in Pb- and Cd-contaminated soils, whereas the activation efficiencies of chelating agents in Tl-contaminated soils were slightly enhanced. View Full-Text
Keywords: heavy metal; thallium; chelating agents; phytoextraction; activation; red soil heavy metal; thallium; chelating agents; phytoextraction; activation; red soil
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Liu, L.; Luo, D.; Yao, G.; Huang, X.; Wei, L.; Liu, Y.; Wu, Q.; Mai, X.; Liu, G.; Xiao, T. Comparative Activation Process of Pb, Cd and Tl Using Chelating Agents from Contaminated Red Soils. Int. J. Environ. Res. Public Health 2020, 17, 497.

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