Iron-bearing mineral phases are ubiquitous in natural environments where they heavily influence several key biogeochemical processes. Their high surface area and (redox) reactivity allow Fe-bearing minerals to control nutrient availability and contaminants mobility through adsorption or structural incorporation. It is therefore important to understand how Fe-bearing minerals interact with nutrients or contaminants when they form or transform in nature, and determine the key geochemical parameters that affect these mineral reactions.
Our current research is mainly focused on the formation and/or transformation of Fe-bearing minerals (e.g., (oxyhydr)oxides, carbonates, phosphates, sulfates) in the presence of co-existing nutrients (e.g., Corg, P, Si) and contaminants (e.g., As, Cr, Pb, Se). Specifically, we synthesize Fe mineral analogues and test them in the laboratory under simulated environmental conditions. We are therefore able to quantify how these elements affect the structure, morphology, phase stability and reactivity of Fe mineral phases; and conversely, how Fe mineral phases impact the speciation and distribution of these elements in the natural environment. In addition to lab-based studies, we also study Fe mineral reactions in natural environments such as in (sub)Arctic soils, wetlands and contaminated soils and groundwater.
(authors from the group in bold)
Perez, J.P.H., Schiefler, A.A., Navaz Rubio, S., Reischer, M., Overheu, N.D., Benning, L.G., Tobler, D.J. (2021): Arsenic removal from natural groundwater using ‘green rust’: Solid phase stability and contaminant fate. Journal of Hazardous Materials, 401, 123327. DOI: 10.1016/j.jhazmat.2020.123327.
Perez, J.P.H., Freeman, H.M., Brown, A.P., van Genuchten, C.M., Dideriksen, K., Tobler, D.J., Benning, L.G. (2020): Direct visualization of arsenic binding on green rust sulfate. Environmental Science & Technology, 4, 6, 3297-3305. DOI: 10.1021/acs.est.9b07092.
Füllenbach, L.C., Perez, J.P.H., Freeman, H.M., Thomas, A.N., Mayanna, S., Parker, J.E., Göttlicher, J., Steininger, R., Radnik, J., Benning, L.G., Oelkers, E.H. (2020). Nanoanalytical identification of siderite dissolution coupled Pb removal mechanisms from oxic and anoxic aqueous solutions. ACS Earth and Space Chemistry, 4, 11, 1966-1977. DOI: 10.1021/acsearthspacechem.0c00180.
Wang, H., Byrne, J., Perez, J.P.H., Thomas, A., Göttlicher, J., Höfer, H., Mayanna, S., Kontny, A., Kappler, A., Guo, H., Benning, L.G., Norra, S. (2020): Arsenic sequestration in pyrite and greigite in the buried peat of As-contaminated aquifers. Geochimica et Cosmochimica Acta, 284, 107-119. DOI: 10.1016/j.gca.2020.06.021.