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Effect of Fe-metabolizing bacteria and humic substances on magnetite nanoparticle reactivity towards arsenic and chromium

DOI: 10.1016/j.jhazmat.2019.121450 DOI Help

Authors: Anneli Sundman (University of Tuebingen) , Anna-Lena Vitzhum (University of Tuebingen) , Konstantin Adaktylos-Surber (University of Tuebingen) , Adriana I. Figueroa (Diamond Light Source) , Gerrit Van Der Laan (Diamond Light Source) , Birgit Daus (Helmholtz Centre for Environmental Research - UFZ) , Andreas Kappler (University of Tuebingen) , James M. Byrne (University of Tuebingen)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Hazardous Materials

State: Published (Approved)
Published: October 2019
Diamond Proposal Number(s): 9565

Abstract: Magnetite is a magnetic, Fe(II)-Fe(III)-mineral formed through abiogenic and biogenic pathways. It constitutes an attractive material for remediation due to its reactivity, large surface-area-to-volume ratio when present as nanoparticles, and magnetic recoverability. Magnetite can be repeatedly microbially oxidized or reduced, but it is unclear how this influences the reactivity of magnetite towards toxic metal or metalloid contaminants. In this study, magnetite (both abiogenic and biogenic) was exposed to microbial Fe(II) oxidation and Fe(III) reduction, before reacted with hexavalent chromium (Cr(VI)) or pentavalent arsenic (As(V)). Results showed microbial reduction of both magnetite types improved the removal rate of Cr(VI) from solution, though surprisingly microbial Fe(II)-oxidation also showed enhanced reactivity towards Cr(VI) compared to un-treated magnetite. Synchrotron based analysis confirmed the formation of Cr(III) at the surface of the magnetite. Reactivity with As was less dramatic and showed un-treated material was able to remove As(V) from solution faster than microbially Fe(III)-reduced and Fe(II)-oxidized magnetite. The presence of humic substances was also shown to lead to a decreased reactivity of biogenic and abiogenic magnetite towards As(V) and Cr(VI). Our results imply that Fe-metabolizing bacteria influence the immobilization of contaminants and should be considered when evaluating remediation schemes, especially where Fe-metabolizing bacteria are active.

Journal Keywords: remediation; pollution; redox cycling; microbes; iron minerals

Diamond Keywords: Bioremediation; Bacteria

Subject Areas: Materials, Environment, Earth Science

Instruments: I10-Beamline for Advanced Dichroism - scattering

Added On: 21/10/2019 14:47

Discipline Tags:

Desertification & Pollution Earth Sciences & Environment Mineralogy Materials Science Geology

Technical Tags:

Spectroscopy Circular Dichroism (CD) X-ray Magnetic Circular Dichroism (XMCD)