Imad Ahmed

Imad Ahmed

Visiting Fellow
Tel: +44 (0)1865 272053

Research Profile

I am an experienced researcher with an established track record in environmental nano-biogeochemistry. Coming from a physical chemistry background, I have a keen interest in understanding interfacial redox reactions at the molecular level in geoenvironmental and engineering systems. Specifically, I am interested in how redox-active nano-materials (e.g., iron oxyhydroxides) form and transform and how their crystalline structure and size define their stability, chemical and biological reactivity in natural systems. My most recent research focuses on constraining iron chemistry on early Earth and Mars where a variety of geochemical processes are investigated especially those involving electron-transfer reactions. Interdisciplinarity is a key feature of my research where analytical, electrochemical and in situ time-resolved synchrotron and neutron-based scattering approaches are implemented and integrated with geochemical speciation models and ab initio molecular dynamics computations.

Recent Research Highlights:

Illustration-1
Tiny magnetic nanoparticles from air pollution have been discovered lodged in the frontal lobes of the cerebral cortex in the human brain. We hypothesized that inhaled airborne pollution particles find their way into the cerebral cortex, cerebellum, the lining surrounding the brain and the spinal cord via the olfactory nerves located in the roof of the nasal cavity.

 

Illustration-2
(a) Parallelepiped and hexagonal projections of peudohexagonal prismatic cuboctahedral magnetite crystals found in bacteria (curtesy Faivre et al., 2005) (b) Bio-magnetite in human brain (curtesy Kirschvink et al., 1992) (c) Brain magnetites discovered by Maher et al., 2016 which resemble the morphology of magnetite particles formed at high temperatures (d).

www.pnas.org/cgi/content/short/1605941113.
See also related news on The University of Oxford website.
Images credit: Imad Ahmed©2016.

 

    1. Maher, B., Ahmed, I.A.M., Karloukovski, V., MacLaren, D.A., Foulds, P.G., Allsop, D., Mann, D.M.A. Torres-Jardón,R. and Calderon-Garciduenas, L.C. (2016) Magnetite pollution nanoparticles in the human brain. PNAS (Full Text) (Abstract)
    1. Ahmed, I.A.M., Taylor, J.H., Bieroza, M., Zhang, H., and Davison, W. (2014) Improving and testing geochemical speciation predictions of metal ions in natural waters. Water Research, 67, 276-291. (Full Text)
    1. Maher, B.A., Ahmed, I.A.M., Davison, B., Karloukovski, V., and Clarke, R. (2013) Impact of roadside tree lines on concentrations of traffic-derived particulate pollutants. Sci. Technol., 47 (23), 13737-13744. (Full Text).
      Highlighted in BBC Two program ‘Trust me I’am a doctor’.
    1. Taylor, J.H., Ahmed, I.A.M., Zhang, H., and Davison, W. (2011) How well can we measure and predict in situ metal speciation in freshwaters? Environmental Chemistry, 8(5) 461-465. (Full Text) (Editor’s highlighted article).
    1. Ahmed, I.A.M., Benning, L.G., Kakonyi, G., Sumoondur, A.D., Terrill, N.J. and Shaw, S. ( 2010 ) Formation of green rust sulfate: a combined in situ time-resolved X-ray scattering and electrochemical study. Langmuir, 26(9), 6593-6603 (Full Text).
    1. Ahmed, I.A.M., Young, S.D., and Crout, N.M.J. (2006) Time-dependent sorption of Cd2+ on CaX zeolite: Experimental observations and model predictions, Cosmochim. Acta, 70, 4850-4861. (Full Text).


JIF = Journal’s 5-years impact factor

    1. Maher, B., Ahmed, I.A.M., Karloukovski, V., MacLaren, D.A., Foulds, P.G., Allsop, D., Mann, D.M.A. Torres-Jardón,R. and Calderon-Garciduenas, L.C. Magnetite pollution nanoparticles in the human brain. PNAS (In review).
    1. Ahmed, I.A.M., Taylor, J.H., Bieroza, M., Zhang, H., and Davison, W. (2014) Improving and testing geochemical speciation predictions of metal ions in natural waters. Water Research, 67, 276-291. (Full Text) JIF = 6.1.
    1. Ahmed, I.A.M, Acero Salazar, P. and Auqué Sanz, L. Modelling approaches of biogeochemical redox processes at the water-mineral interface. In Redox-active materials: properties, reactions and applications in clean technologies, Ahmed, I. & Hudson-Edwards, K. (Eds.). EMU notes in Mineralogy, Vol 16. The Mineralogical Society, London. Accepted for publication.
    1. Maher, B.A., Ahmed, I.A.M., Davison, B., Karloukovski, V., and Clarke, R. (2013) Impact of roadside tree lines on concentrations of traffic-derived particulate pollutants. Sci. Technol., 47 (23), 13737-13744. (Full Text) Highlighted in a recent BBC Two program ‘Trust me I’am a doctor’. JIF = 5.3
    1. Rogers, C.M., Burke, I.T., Ahmed, I.A.M., and Shaw, S. (2013) Immobilization of Chromate in Hyperalkaline Waste Streams by Green Rusts and Zero-Valent Iron. Environmental Technology, 35 (4), 508-513. (Full Text). JIF = 1.6
    1. Ahmed, I.A.M., Taylor, J.H., Lofts S., Meeussen, J.C.L., Lin C., Zhang, H., and Davison, W. (2013) Testing Copper-Speciation Predictions in Freshwaters over a Wide Range of Metal-Organic Matter Ratios. Sci. Technol., 47 (3), 1487-1495. (Full Text). JIF = 5.3
    1. Ahmed, I.A.M. (2012) Vanadium and Chromium Groups. In Encyclopedia of Environmental Management; S.E. Jorgensen, ed. Taylor & Francis: New York, Vol. IV, pp. 2582-2594. ISBN 9781439829271. (Full Text)
    1. Kakonyi, G. and Ahmed, I.A.M. (2012) Cadmium and Lead: Contamination. In Encyclopedia of Environmental Management; S.E. Jorgensen, ed. Taylor & Francis: New York, Vol. I, pp. 446-452. ISBN 9781439829271. (Full Text)
    1. Taylor, J.H., Ahmed, I.A.M., Zhang, H., and Davison, W. (2011) How well can we measure and predict in situ metal speciation in freshwaters? Environmental Chemistry, 8(5) 461-465. (Full Text) (Editor’s highlighted article). JIF = 2.7
    1. Ahmed, I.A.M., Shaw, S., Benning, L.G., and Kakonyi, G. (2010) In situ studies of green rust formation using synchrotron-based X-ray scattering: helping to develop a new range of environmental materials. ECG Bulletin. ISSN 1758-6224 (Print) 3-5 (Full Text)
    1. Ahmed, I.A.M., Young, S.D., and Crout, N.M.J. (2010) Ageing and structural effects on the sorption characteristics of Cd2+ by clinoptilolite and Y-type zeolite studied using isotope exchange technique. Journal of Hazardous Materials, 184(1-3), pp. 574-584 (Full Text). JIF = 4.7
    1. Ahmed, I.A.M., Benning, L.G., Kakonyi, G., Sumoondur, A.D., Terrill, N.J. and Shaw, S. ( 2010 ) Formation of green rust sulfate: a combined in situ time-resolved X-ray scattering and electrochemical study. Langmuir, 26(9), 6593-6603 (Full Text). JIF = 4.6
    1. Ahmed, I.A.M. (2010) The formation and stability of Green Rust: Developing nanomaterials for environmental cleanup. Diamond Light Source, Annual Science Report 2009/2010 (Full Text; Website)
    1. Ahmed, I.A.M., Bailey, E.H., Young, S.D., Mosselmans, J.F.W., and Crout, N.M.J. (2009) Coordination of Cd2+ ions in the internal pore system of zeolite-X: A combined EXAFS and isotopic exchange study. Cosmochim. Acta, 73(6), 1587-1577 (Full Text). JIF = 4.5
    1. Ahmed, I.A.M., Shaw, S., and Benning, L.G. (2008) Formation of hydroxysulphate and hydroxycarbonate green rusts in the presence of zinc using time-resolved in situ small and wide angle X-ray scattering. Mineralogical Magazine, 72(1), 1-4 (Full Text). JIF = 2.2
    1. Sumoondur A., Shaw, S., Ahmed, I.A.M., and Benning L.G. (2008) Green rust a precursor for magnetite: an in situ synchrotron based study. Mineralogical Magazine, 72(1), 43-46. (Full Text). JIF = 2.2
    1. Ahmed, I.A.M., and Shaw, S. (2008) Can green rust save the day? Synchrotron Radiation Department, Daresbury Laboratory – Annual Science Report 2007-2008, pp 10-11. (Full Text)
    1. Ahmed, I.A.M., Young, S.D., and Crout, N.M.J. (2008) Kinetics of Cd sorption, desorption and fixation by calcite: A long-term radiotracer study. Cosmochim. Acta, 72, 6, 1498-1512. (Full Text). JIF = 4.5
    1. Ahmed, I.A.M., Young, S.D., and Crout, N.M.J. (2006) Time-dependent sorption of Cd2+ on CaX zeolite: Experimental observations and model predictions, Cosmochim. Acta, 70, 4850-4861. (Full Text). JIF = 4.5

    1. Ahmed, I.A.M. and Hudson-Edwards, K. (Eds.), (2016) Redox-active materials: properties, reactions and applications in natural systems and clean technologies. EMU Notes in Mineralogy, Vol 17. The Mineralogical Society, London. ISBN: 9780903056571.http://www.minersoc.org/EMU-notes-16.html

    1. Ahmed, I.A.M., Keen, D., Tosca, N.J. (2016). Uncovering the structural basis behind the reactivity of white rust: An X-ray and neutron total scattering study. Goldschmidt, Yokohama, Japan. (Full Text)
    1. Tostevin, R., Tosca, N.J., Ahmed, I.A.M. (2016) Bio-Essential Trace Metal Cycling in a Ferruginous, Silica Rich Ocean. Goldschmidt, Yokohama, Japan. (Full Text)
    1. Jiang, C. Z., Ahmed, I.A.M., Tosca, N.J. (2016) Fe(II)-carbonate Precipitation Kinetics and Precambrian Seawater Chemistry. Goldschmidt, Yokohama, Japan. (Full Text)
    1. Ahmed, I.A.M., Taylor, J.H., Zhang, H., and Davison, W. (2012) Testing predictive capabilities of speciation models in freshwaters using a laboratory-assay approach. 4th Congress of the European Association for Chemical and Molecular Sciences, Prague, Czech Republic, August 26 – 30.
    1. Ahmed, I.A.M. (July 2012) Formation of green rust sulfate and carbonate in the presence of Zn using time-resolved in situ Small- and Wide-Angle X-ray Scattering. I09 Workshop on Atomic and Electronic Structures of Surfaces and Interfaces, Diamond Light Source, Oxfordshire, UK.
    1. Rogers C., Shaw, S. Burke, I., and Ahmed, I.A.M. (2010) Cr(VI) Removal from alkaline COPR leachate using green rust. Cosmochim. Acta, 74 (12, Suppl. 1). A843-A896. (Full Text)
    1. Shaw, S., Ahmed, I.A.M., Benning, L.G., Kakonyi, G., Sumoondur, A.D., and Terrill, N.J. (2009), Green rust nanoparticle formation, stability and oxidation, and its role in natural and engineered systems, Eos Trans. AGU, 90(52), Fall Meet. Suppl., Abstract V43C-2270.
    1. Kakonyi, G., Shaw, S., Ahmed, I.A.M., Benning, L.G. (2008) The formation and oxidation of green rust: Mechanisms, kinetics and trace element speciation. Cosmochim. Acta, 72, 12, Suppl. 1, pp. A445 (Full Text)
    1. Shaw, S., Ahmed, I.A.M., Benning, L.G., Kakonyi, G., Behrends, T. (2008) Synchrotron-based X-ray scattering studies of mineral reactions in complex geochemical systems. Cosmochim. Acta, 72, 12, Suppl. 1, pp. A853 (Full Text)
    1. Sumoondur, A.D., Shaw, S., Ahmed, I.A.M., Benning, L.G. (2008) Green rust is a precursor to magnetite: Direct evidence from an in situ diffraction study. Cosmochim. Acta, 72, 12, Suppl. 1, pp. A913 (Full Text)
    1. Ahmed, I.A.M., Kakonyi, G., Benning, L.G., Shaw, S. (2008) An in situ SAXS/WAXS study of sulfate- and carbonate-green rust formation. Cosmochim. Acta, 72, 12, Suppl. 1, pp. A9 (Full Text)
    1. Ahmed, I.A.M., Benning, L.G., Shaw, S. (2008) Formation of sulphate and carbonate green rusts in the presence of zinc using time-resolved in situ Small and Wide Angle X-ray Scattering, Geochemistry of the Earth’s Surface 8 (GES8), Natural History Museum, London.