Tags

Type your tag names separated by a space and hit enter

Comparison of two sequential extraction procedures for heavy metal partitioning in mine tailings.
Chemosphere. 2010 Mar; 78(11):1393-402.C

Abstract

This study aimed at elucidating the fractionation of Cd, Zn and Pb in mine tailings and evaluating the extraction selectivity of different extractants--and thus the efficiency of two sequential extraction procedures. For the purpose of figuring out the applicability of different sequential extraction procedures (SEP's) in Cd, Zn and Pb fractionation in mine tailings, two SEP's (i) modified BCR and (ii) Tessier's scheme were applied to mine tailings (new as well as old). To compare the results obtained by two methods having different number of fractions (four and five respectively), the fractions were rearranged into four "equivalent fractions" defined as acid soluble, reducible, oxidisable and residual. Systematic variations in the "reducible" fraction, i.e. the content of metal in the reducible fractions obtained by Tessier's procedure were, in general, higher than those obtained by BCR scheme. This may be attributed to stronger conditions used in Tessier's scheme to extract this fraction. This shows that the fractions are only empirically (operationally) defined and are not totally exclusive to the specified mineral phase. Percentages of Cd, Zn and Pb extracted in the organic fraction by modified BCR scheme were always higher than those obtained by Tessier's scheme. Based on the fractionation results by both the schemes, it appears that as compared to Cd and Zn, Pb has lower extraction yield in old tailings as compared to new tailings in organic/sulphides bound fraction. This can be explained by the formation of secondary Pb minerals of low solubility, formed by the oxidation of sulphides in old tailings as a result of weathering. Speciation data indicate that Cd has the greatest affinity in the acid soluble fraction, Pb is associated with the reducible fraction and Zn is incorporated into the residual fraction (crystalline silicate matrices) irrespective of the solid matrix type. The metal associations in the oxidizable fraction appear to be matrix specific, i.e., Zn dominates this fraction in new tailings and Pb in old tailings.

Authors+Show Affiliations

School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India. anjumalik27@yahoo.comNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20106503

Citation

Anju, M, and D K. Banerjee. "Comparison of Two Sequential Extraction Procedures for Heavy Metal Partitioning in Mine Tailings." Chemosphere, vol. 78, no. 11, 2010, pp. 1393-402.
Anju M, Banerjee DK. Comparison of two sequential extraction procedures for heavy metal partitioning in mine tailings. Chemosphere. 2010;78(11):1393-402.
Anju, M., & Banerjee, D. K. (2010). Comparison of two sequential extraction procedures for heavy metal partitioning in mine tailings. Chemosphere, 78(11), 1393-402. https://doi.org/10.1016/j.chemosphere.2009.12.064
Anju M, Banerjee DK. Comparison of Two Sequential Extraction Procedures for Heavy Metal Partitioning in Mine Tailings. Chemosphere. 2010;78(11):1393-402. PubMed PMID: 20106503.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparison of two sequential extraction procedures for heavy metal partitioning in mine tailings. AU - Anju,M, AU - Banerjee,D K, Y1 - 2010/01/27/ PY - 2009/06/24/received PY - 2009/12/23/revised PY - 2009/12/26/accepted PY - 2010/1/29/entrez PY - 2010/1/29/pubmed PY - 2010/6/23/medline SP - 1393 EP - 402 JF - Chemosphere JO - Chemosphere VL - 78 IS - 11 N2 - This study aimed at elucidating the fractionation of Cd, Zn and Pb in mine tailings and evaluating the extraction selectivity of different extractants--and thus the efficiency of two sequential extraction procedures. For the purpose of figuring out the applicability of different sequential extraction procedures (SEP's) in Cd, Zn and Pb fractionation in mine tailings, two SEP's (i) modified BCR and (ii) Tessier's scheme were applied to mine tailings (new as well as old). To compare the results obtained by two methods having different number of fractions (four and five respectively), the fractions were rearranged into four "equivalent fractions" defined as acid soluble, reducible, oxidisable and residual. Systematic variations in the "reducible" fraction, i.e. the content of metal in the reducible fractions obtained by Tessier's procedure were, in general, higher than those obtained by BCR scheme. This may be attributed to stronger conditions used in Tessier's scheme to extract this fraction. This shows that the fractions are only empirically (operationally) defined and are not totally exclusive to the specified mineral phase. Percentages of Cd, Zn and Pb extracted in the organic fraction by modified BCR scheme were always higher than those obtained by Tessier's scheme. Based on the fractionation results by both the schemes, it appears that as compared to Cd and Zn, Pb has lower extraction yield in old tailings as compared to new tailings in organic/sulphides bound fraction. This can be explained by the formation of secondary Pb minerals of low solubility, formed by the oxidation of sulphides in old tailings as a result of weathering. Speciation data indicate that Cd has the greatest affinity in the acid soluble fraction, Pb is associated with the reducible fraction and Zn is incorporated into the residual fraction (crystalline silicate matrices) irrespective of the solid matrix type. The metal associations in the oxidizable fraction appear to be matrix specific, i.e., Zn dominates this fraction in new tailings and Pb in old tailings. SN - 1879-1298 UR - https://www.unboundmedicine.com/medline/citation/20106503/Comparison_of_two_sequential_extraction_procedures_for_heavy_metal_partitioning_in_mine_tailings_ DB - PRIME DP - Unbound Medicine ER -