Arab, KAH, Thompson, DF and Oliver, IW (2021) Evaluation and characterisation of metal sorption and retention by drinking water treatment residuals (WTRs) for environmental remediation. International Journal of Environmental Science and Technology. ISSN 1735-1472

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Drinking water treatment residuals (WTRs) are wastes generated when water is clarified using aluminium or iron salts. They are increasingly being considered as a resource with potential reuse value, particularly in relation to soil or water remediation. Adsorption–desorption capacity of Al-based (Al-WTR) and Fe-based (Fe-WTR) materials was investigated here for Pb and Zn, both separately and in combination, as a preliminary trial to assess their utility for immobilising contaminant metals in environmental settings. Maximum adsorption observed at the highest test solution concentrations imposed (400 mg/L) was similar for each WTR type and each metal; Al-WTRs sorbed Zn at 3579 mg/kg and Pb at 4025 mg/kg, while Fe-WTRs sorbed Zn and Pb at 3579 mg/kg and 3980 mg/kg, respectively. Equilibrium adsorption data were tested against Langmuir, Freundlich, and Temkin isotherm models, which indicated a substantial reserve capacity for further Pb sorption and that multiple sorption mechanisms were involved. Subsequent desorption tests with 0.001 M CaCl<jats:sub>2</jats:sub> solution indicated that &gt; 89.76% of sorbed metal remained sorbed. When in solution together, both metals were strongly sorbed by WTRs, but a slight preference for Pb was observed. The results indicate that WTRs would be very effective immobilising agents if placed in contaminated soil or if used to treat contaminated waters.

Item Type: Article
Additional Information: Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit
Uncontrolled Keywords: Water treatment residuals · Adsorption · Isotherms · Remediation · Lead · Zinc
Subjects: G Geography. Anthropology. Recreation > G Geography (General)
G Geography. Anthropology. Recreation > GE Environmental Sciences
Q Science > QE Geology
Divisions: Faculty of Natural Sciences > School of Geography, Geology and the Environment
Depositing User: Symplectic
Date Deposited: 04 Nov 2021 15:10
Last Modified: 30 Nov 2021 09:41

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