The University of Southampton
University of Southampton Institutional Repository

Structural and magnetic studies on heavy-metal-adsorbing iron sulphide nanoparticles produced by sulphate-reducing bacteria

Structural and magnetic studies on heavy-metal-adsorbing iron sulphide nanoparticles produced by sulphate-reducing bacteria
Structural and magnetic studies on heavy-metal-adsorbing iron sulphide nanoparticles produced by sulphate-reducing bacteria
In previous and in work to be published, it has been shown that iron sulphide material, produced by sulphate-reducing bacteria (SRB), is an excellent adsorbent for a wide range of heavy metals. The material adsorbs between 100 and 400 mg g?1 and residual levels in solutions can be of the order of pg per litre. Further, strongly magnetic forms of this material can now be produced which can be effectively and cheaply removed from suspension together with the adsorbate by magnetic separation. This paper examines the structure of weakly magnetic and strongly magnetic iron sulphide material produced by SRB with a view to increasing the understanding of its adsorbent and the magnetic properties. The structural properties have been examined using high-resolution imaging and electron diffraction in a transmission electron microscope (TEM), the measurements of magnetisation versus field and temperature, extended X-ray absorption fine-structure (EXAFS) spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy and neutron diffraction. Before drying the surface area of both the weakly magnetic and the strongly magnetic iron sulphide is of the order of 400–500 m2 g?1 as revealed by the magnetic properties, neutron scattering and the adsorption of a number of heavy metals. After freeze-drying the surface area falls to between 18 and 19 m2 g?1. The initial inocula came from a semi-saline source and when fed with nutrient containing Fe2+ and Fe3+ produced a weakly magnetic iron sulphide (Watson et al., Minerals Eng. 8 (1995) 1097) and a few % of a more strongly magnetic material. Further work using a novel method (Keller-Besrest, Collin, J. Solid State Chem. 84 (1990) 211) produced a strongly magnetic iron sulphide material. EXAFS and XANES spectroscopy revealed (Keller-Besrest and Collin, 1990) that the weakly magnetic iron sulphide material had the Ni–As structure in which the Fe is tetrahedrally coordinated with the composition Fe1?xS. The strongly magnetic iron sulphide was composed of some greigite (Fe3S4) and mackinawite (Fe1+xS), however, the bulk of the material at room temperature probably consists of disordered greigite and mackinawite. The weakly magnetic and strongly magnetic iron sulphide are good adsorbents for heavy metals and halogenated hydrocarbons.
Sulphate-reducing bacteria, Iron sulphides, Nanoparticles, Magnetic properties, Structure
0304-8853
13-30
Watson, J.H.P.
e4f7e9d2-6299-4626-bc44-1ee8545899e6
Cressey, B.A.
55c72b25-9179-4338-ac8f-c71f7613d44e
Roberts, A.P.
4497b436-ef02-428d-a46e-65a22094ba52
Ellwood, D.C.
a7dc8f2a-f392-42b4-a022-fa5a58cf6be6
Charnock, J.M.
d00ebdb2-43da-40a5-82e1-655bf8a09230
Soper, A.K.
7903185f-a643-445a-8a39-9a59bcffab9b
Watson, J.H.P.
e4f7e9d2-6299-4626-bc44-1ee8545899e6
Cressey, B.A.
55c72b25-9179-4338-ac8f-c71f7613d44e
Roberts, A.P.
4497b436-ef02-428d-a46e-65a22094ba52
Ellwood, D.C.
a7dc8f2a-f392-42b4-a022-fa5a58cf6be6
Charnock, J.M.
d00ebdb2-43da-40a5-82e1-655bf8a09230
Soper, A.K.
7903185f-a643-445a-8a39-9a59bcffab9b

Watson, J.H.P., Cressey, B.A., Roberts, A.P., Ellwood, D.C., Charnock, J.M. and Soper, A.K. (2000) Structural and magnetic studies on heavy-metal-adsorbing iron sulphide nanoparticles produced by sulphate-reducing bacteria. Journal of Magnetism and Magnetic Materials, 214, 13-30. (doi:10.1016/S0304-8853(00)00025-1).

Record type: Article

Abstract

In previous and in work to be published, it has been shown that iron sulphide material, produced by sulphate-reducing bacteria (SRB), is an excellent adsorbent for a wide range of heavy metals. The material adsorbs between 100 and 400 mg g?1 and residual levels in solutions can be of the order of pg per litre. Further, strongly magnetic forms of this material can now be produced which can be effectively and cheaply removed from suspension together with the adsorbate by magnetic separation. This paper examines the structure of weakly magnetic and strongly magnetic iron sulphide material produced by SRB with a view to increasing the understanding of its adsorbent and the magnetic properties. The structural properties have been examined using high-resolution imaging and electron diffraction in a transmission electron microscope (TEM), the measurements of magnetisation versus field and temperature, extended X-ray absorption fine-structure (EXAFS) spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy and neutron diffraction. Before drying the surface area of both the weakly magnetic and the strongly magnetic iron sulphide is of the order of 400–500 m2 g?1 as revealed by the magnetic properties, neutron scattering and the adsorption of a number of heavy metals. After freeze-drying the surface area falls to between 18 and 19 m2 g?1. The initial inocula came from a semi-saline source and when fed with nutrient containing Fe2+ and Fe3+ produced a weakly magnetic iron sulphide (Watson et al., Minerals Eng. 8 (1995) 1097) and a few % of a more strongly magnetic material. Further work using a novel method (Keller-Besrest, Collin, J. Solid State Chem. 84 (1990) 211) produced a strongly magnetic iron sulphide material. EXAFS and XANES spectroscopy revealed (Keller-Besrest and Collin, 1990) that the weakly magnetic iron sulphide material had the Ni–As structure in which the Fe is tetrahedrally coordinated with the composition Fe1?xS. The strongly magnetic iron sulphide was composed of some greigite (Fe3S4) and mackinawite (Fe1+xS), however, the bulk of the material at room temperature probably consists of disordered greigite and mackinawite. The weakly magnetic and strongly magnetic iron sulphide are good adsorbents for heavy metals and halogenated hydrocarbons.

Full text not available from this repository.

More information

Published date: 2000
Keywords: Sulphate-reducing bacteria, Iron sulphides, Nanoparticles, Magnetic properties, Structure

Identifiers

Local EPrints ID: 13530
URI: https://eprints.soton.ac.uk/id/eprint/13530
ISSN: 0304-8853
PURE UUID: f377af52-588b-4a55-befc-f1b0f777fcde

Catalogue record

Date deposited: 08 Dec 2004
Last modified: 17 Jul 2017 17:02

Export record

Altmetrics

Contributors

Author: J.H.P. Watson
Author: B.A. Cressey
Author: A.P. Roberts
Author: D.C. Ellwood
Author: J.M. Charnock
Author: A.K. Soper

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×