| People | Locations | Statistics |
|---|---|---|
| Naji, M. |
| |
| Motta, Antonella |
| |
| Aletan, Dirar |
| |
| Mohamed, Tarek |
| |
| Ertürk, Emre |
| |
| Taccardi, Nicola |
| |
| Kononenko, Denys |
| |
| Petrov, R. H. | Madrid |
|
| Alshaaer, Mazen | Brussels |
|
| Bih, L. |
| |
| Casati, R. |
| |
| Muller, Hermance |
| |
| Kočí, Jan | Prague |
|
| Šuljagić, Marija |
| |
| Kalteremidou, Kalliopi-Artemi | Brussels |
|
| Azam, Siraj |
| |
| Ospanova, Alyiya |
| |
| Blanpain, Bart |
| |
| Ali, M. A. |
| |
| Popa, V. |
| |
| Rančić, M. |
| |
| Ollier, Nadège |
| |
| Azevedo, Nuno Monteiro |
| |
| Landes, Michael |
| |
| Rignanese, Gian-Marco |
|
Shaw, Samuel
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (9/9 displayed)
- 2022Hydrotalcite colloid stability and interactions with uranium(VI) at neutral to alkaline pH.citations
- 2021A spectroscopic study of trivalent cation (Cm3+ and Eu3+) sorption on monoclinic zirconia (ZrO2)citations
- 2019U(VI) sorption during ferrihydrite formation: Underpinning radioactive effluent treatmentcitations
- 2019A spectroscopic study of trivalent cation (Cm3+ and Eu3+) sorption on monoclinic zirconia (ZrO2)citations
- 2018Stability, composition and core-shell particle structure of uranium(IV)-silicate colloidscitations
- 2016Release of Ni from birnessite during transformation of birnessite to todorokite: Implications for Ni cycling in marine sedimentscitations
- 2014Nucleation and growth of todorokite from birnessite: Implications for trace-metal cycling in marine sedimentscitations
- 2013Partitioning of Pb(II) during goethite and hematite crystallization: Implications for Pb transport in natural systemscitations
- 2006The rate of ferrihydrite transformation to goethite via the Fe(II) pathwaycitations
Places of action
| Organizations | Location | People |
|---|
article
Nucleation and growth of todorokite from birnessite: Implications for trace-metal cycling in marine sediments
Abstract
The phyllomanganate birnessite is the main Mn-bearing phase in oxic marine sediments, and through coupled sorption and redox exerts a strong control on the oceanic concentration of micronutrient trace metals. However, under diagenesis and mild hydrothermal conditions, birnessite undergoes transformation to the tectomanganate todorokite. The mechanistic details of this transformation are important for the speciation and mobility of metals sequestered by birnessite, and are necessary in order to quantify the role of marine sediments in global trace element cycles. Here we transform a synthetic, poorly crystalline, hexagonal birnessite, analogous to marine birnessite, into todorokite under a mild reflux procedure, developed to mimic marine diagenesis and mild hydrothermal conditions. We characterize our birnessite and reflux products as a time series, employing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET surface area analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and extended X-ray absorption fine structure spectroscopy (EXAFS). We provide new insight into the crystallization pathway and mechanism of todorokite formation from birnessite under conditions analogous to those found in marine diagenetic and hydrothermal settings. Specifically we propose a new four-stage process for the transformation of birnessite to todorokite, beginning with todorokite nucleation, then crystal growth from solution to form todorokite primary particles, followed by their self-assembly and oriented growth via oriented attachment to form crystalline todorokite laths, culminating in traditional crystal ripening. We suggest that, contrary to current understanding, trace metals like Ni might retard the transformation of birnessite to todorokite and be released to marine sedimentary pore-waters during this diagenetic process, thus potentially providing a benthic flux of these micronutrients to seawater.