Based on a plethora of experiments and advanced geochemical analysis techniques, Hussein Kanbar in the Holmboe group (Department of Chemistry/UMU), in a collaboration with PhD student Fredrik Olajos and Professor Göran Englund from the Department of Ecology and Environmental Sciences/UMU, has published a paper in the Journal of Soils and Sediments, detailing the mineral and geochemical characteristics of Holocene lake sediments from the Hotagen lake in west Sweden (Jämtland). Read more here:
Kanbar, H.J., Tran Le, T., Olajos, F. et al. Tracking mineral and geochemical characteristics of Holocene lake sediments: the case of Hotagen, west-central Sweden. J Soils Sediments (2021). https://doi.org/10.1007/s11368-021-03012-y
Our planet has more organic carbon in its fragile soil layers than all the carbon on land and atmosphere combined. The Holmboe group is now hiring a PhD student (4 year minimum) and offering one postdoc fellowship (2 years) for two separate but similar projects focusing on the molecular interactions between natural organic molecules and mineral surfaces.
In order to focus on the molecular scale, the research will utilize various experimental methods and molecular dynamics simulations (extracting for instance free energy profiles as shown below), and why not also virtual reality!
To apply for the PhD position, please visit this link.
To apply for the postdoc fellowship financed by the Kempe Foundations, please visit this link.
Hussein Kanbar and Michael Holmboe has collaborated with EMG/UMU Prof. Göran Englund and PhD student Fredrik Olajos, on the faith of (ancient)DNA adsorbed onto minerals in 10,000 y old Swedish lake sediments. Their first publication is now available online at: doi.org/10.1016/j.apgeochem.2020.104728.
- Lake sediment geochmemistry plays a significant role in the sorption.
- Clays were the main sedimentary components to host DNA.
- Both clay-mineral and organo-clay complexes govern the sorption of DNA.
- A DNA infrared fingerprint was determined in sediments via spectral subtraction.
- DNA-hotspots in lake sediments were revealed using geochemical approaches.
Michael Holmboe which initially joined the Chemistry Dept. at Umeå University in 2015 as an assistant professor, has now been appointed to associate professor (universitetslektor) in inorganic chemistry!
Thanks to recent grants from SSM and VR, his groups research is set to start two new projects regarding radiation-induced redox effects in clay minerals and organic/minerals interactions using molecular simulations!
The Swedish Radiation Safety Authority, or SSM in short, are funding a 1-year project in the Holmboe group!
In the context of nuclear waste disposal in Sweden and many other countries, this project will investigate the effects of redox and physicochemical changes induced by gamma (γ) irradiation on compacted Bentonite clay and its main component montmorillonite. This is relevant since in nuclear waste repository concepts such as the Swedish KBS-3, the compacted and water saturated Bentonite clay buffer will unavoidably be exposed to significant doses (40-200kGy) of ionizing 137-Cs radiation, which may induce redox-changes in the structural Fe(II)/Fe(III) sites in the clay mineral lattice.
A recent article in NyTeknik (link) highlights recent findings in a US study funded by the DOE titled ‘Self-accelerated corrosion of nuclear waste forms at material interfaces’. In the NyTeknik article associate prof. Michael Holmboe is interviewed and comments on the relevance of the results for the planned nuclear waste disposal in Sweden.
The Swedish Research Council (Vetenskapsrådet, VR) has awarded Michael Holmboe a 4-year research project grant, for a project focusing on adsorption of biogeochemical organics to clays and similar minerals!
Deconvolution of Smectite Hydration Isotherms
Authors: Jerry Lindholm, Jean-Francois Boily and Michael Holmboe.
Sorption isotherm models have traditionally served as an invaluable tool to characterize synthesized and natural mineral particles, but often fail to describe the behavior of swelling materials. This research presents a novel composite isotherm model that describes water uptake by adsorption, step-wise intercalation, and condensation.
Michael Holmboe’s collaboration with researchers (Ruth Tinnacher, CSUEastBay and Christophe Tournassat, LBNL, BRGM) in the US focusing on uranyl complex – clay transport and interactions was highlighted in the evening newspaper Expressen, forskning.se and (initially) by the faculty news.
Michae Holmboe gave an invited talk on the characterization of clay microstructure and molecular dynamics simulations – at the workshop “Clays, New Perspectives, Challenges & Opportunities”, May 2-3 2019, hosted by Prof Andrew Whittle and his postdoc Ali Seiphoori at the Massachusetts Institute of Technology (MIT). Read more here: clays.mit.edu