In situ arsenic oxidation and sorption by a Fe-Mn binary oxide waste in soil

Clare M McCann; Caroline L Peacock; Karen A Hudson-Edwards; Thomas Shrimpton; Neil D Gray; Karen L Johnson

doi:10.1016/j.jhazmat.2017.08.066

In situ arsenic oxidation and sorption by a Fe-Mn binary oxide waste in soil

J Hazard Mater. 2018 Jan 15:342:724-731. doi: 10.1016/j.jhazmat.2017.08.066. Epub 2017 Sep 19.

Authors

Clare M McCann¹, Caroline L Peacock², Karen A Hudson-Edwards³, Thomas Shrimpton¹, Neil D Gray¹, Karen L Johnson⁴

Affiliations

¹ School of Civil Engineering and Geosciences, Newcastle University, Newcastle, NE1 7RU, UK.
² School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
³ Camborne School of Mines and Environment and Sustainability Institute, University of Exeter, Tremough Campus, Penryn TR10 9EZ, UK.
⁴ School of Engineering and Computer Sciences, Durham University, Durham, DH1 3LE, UK. Electronic address: karen.johnson@durham.ac.uk.

PMID: 28918290
DOI: 10.1016/j.jhazmat.2017.08.066

Abstract

The ability of a Fe-Mn binary oxide waste to adsorb arsenic (As) in a historically contaminated soil was investigated. Initial laboratory sorption experiments indicated that arsenite [As(III)] was oxidized to arsenate [As(V)] by the Mn oxide component, with concurrent As(V) sorption to the Fe oxide. The binary oxide waste had As(III) and As(V) adsorption capacities of 70mgg^-1 and 32mgg^-1 respectively. X-ray Absorption Near-Edge Structure and Extended X-ray Absorption Fine Structure at the As K-edge confirmed that all binary oxide waste surface complexes were As(V) sorbed by mononuclear bidentate corner-sharing, with 2 Fe at ∼3.27Ǻ. The ability of the waste to perform this coupled oxidation-sorption reaction in real soils was investigated with a 10% by weight addition of the waste to an industrially As contaminated soil. Electron probe microanalysis showed As accumulation onto the Fe oxide component of the binary oxide waste, which had no As innately. The bioaccessibility of As was also significantly reduced by 7.80% (p<0.01) with binary oxide waste addition. The results indicate that Fe-Mn binary oxide wastes could provide a potential in situ remediation strategy for As and Pb immobilization in contaminated soils.

Keywords: Arsenic; Fe-Mn binary oxide; Lead; Remediation; Soil.