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Characteristics and Mechanisms of Pb(II) Sorption onto Fe-rich waste Water Treatment Residue (WTR): A potential sustainable Pb immobilisation technology for soils

Findlay, Nina C.; Peacock, Caroline L.; Hudson-Edwards, Karen A.; Johnson, Karen L.

Characteristics and Mechanisms of Pb(II) Sorption onto Fe-rich waste Water Treatment Residue (WTR): A potential sustainable Pb immobilisation technology for soils Thumbnail


Authors

Nina C. Findlay

Caroline L. Peacock

Karen A. Hudson-Edwards



Abstract

Pb contamination of soils is a global problem. This paper discusses the ability of an Fe-rich waste, water treatment residual (WTR), to adsorb Pb(II). This was investigated using batch sorption experiments, X-ray diffraction, electron microprobe microanalysis, PHREEQC modelling and Extended X-ray Absorption Fine Structure (EXAFS) analysis. The WTR is composed of approximately 23 wt. % natural organic matter (NOM), 70 wt. % ferrihydrite and <10 wt. % silicate material. Pb(II) sorption to WTR was dependent on initial Pb(II) load, particle size, time and pH, but not on ionic strength. EXAFS analysis at the Pb LIII-edge confirmed that Pb(II) sorbed to WTR by co-existing bidentate edge-sharing and monodentate or corner-sharing complexes, with 2 O at ∼2.31–2.34 Å, 1 Fe at ∼3.32–3.34 Å, 2 Fe at ∼3.97–3.99 Å and 1 Pb at ∼3.82–3.85 Å. Linear combination showed that the Pb(II)-sorbed spectra were best fit with a ∼0.9 ± 0.1 and 0.1 ± 0.1 contribution from Pb(II)-sorbed ferrihydrite and Pb(II)-sorbed humic acid end members, respectively. Overall, we show that Pb(II) sorbs via strong inner-sphere complexation of Pb(II) to the ferrihydrite component of the WTR, which itself is stable over a wide pH range. Therefore, we suggest that Fe-rich WTR wastes could be used as effective adsorbents in Pb(II)-contaminated soils to help ensure sustainable terrestrial ecosystems.

Citation

Findlay, N. C., Peacock, C. L., Hudson-Edwards, K. A., & Johnson, K. L. (2021). Characteristics and Mechanisms of Pb(II) Sorption onto Fe-rich waste Water Treatment Residue (WTR): A potential sustainable Pb immobilisation technology for soils. Journal of Hazardous Materials, 402, Article 123433. https://doi.org/10.1016/j.jhazmat.2020.123433

Journal Article Type Article
Acceptance Date Jul 6, 2020
Online Publication Date Jul 8, 2020
Publication Date Jan 15, 2021
Deposit Date Jul 9, 2020
Publicly Available Date Mar 29, 2024
Journal Journal of Hazardous Materials
Print ISSN 0304-3894
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 402
Article Number 123433
DOI https://doi.org/10.1016/j.jhazmat.2020.123433

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