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In situ fixation of metals using bauxite residue: chemical assessment.

Lombi, Enzo and Zhao, Fang Jie and Zhang, Gangya and Sun, Bo and Fitz, Walter and Zhang, Hao and McGrath, Steve P. (2002) In situ fixation of metals using bauxite residue: chemical assessment. Environmental Pollution, 118 (3). pp. 435-444. ISSN 0269-7491

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Abstract

Contamination of soils with heavy metals and metalloids is a widespread problem all over the world. Low cost, non-invasive, in situ technologies are required for remediation processes. We investigated the efficiency of a bauxite residue (red mud) to fix heavy metals in two soils, one contaminated by industrial activities (French soil), and one by sewage sludge applications (UK soil). This Fe-oxide rich material was compared with lime, or beringite, a modified aluminosilicate that has been used for in situ fixation processes. Four different crop species were successively grown in pots. Metal concentrations in the soil pore waters were analyzed during the growing cycles. At the end of the experiment fluxes of heavy metals were measured using a diffusive gradient in thin film technique (DGT). Furthermore, a sequential extraction procedure (SEP) and an acidification test were performed to investigate the mechanisms of metal fixation by different soil amendments. In both soils, the concentrations of metals in the soil pore water and metal fluxes were greatly decreased by the amendments. An application of 2% red mud performed as well as beringite applied at 5%. Increasing soil pH was a common mechanism of action for all the amendments. However, the red mud amendment shifted metals from the exchangeable to the Fe-oxide fraction, and decreased acid extractability of metals. The results suggest that specific chemisorption, and possibly metal diffusion into oxide particles could also be the mechanisms responsible for the fixation of metals by red mud.

Item Type: Article
Journal or Publication Title: Environmental Pollution
Uncontrolled Keywords: In situ fixation ; Remediation ; Heavy metals ; Red mud ; Beringite ; Contaminated soils
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 21478
Deposited By: ep_ss_importer
Deposited On: 15 Jan 2009 10:54
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 15:47
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/21478

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