A5012559481- Calcium Carbonate Crystallization and Inhibition
- Geology and Paleoclimatology Research
- Minerals Flotation and Separation Techniques
- Iron oxide chemistry and applications
- Mine drainage and remediation techniques
- Paleontology and Stratigraphy of Fossils
- Arsenic contamination and mitigation
- Geochemistry and Elemental Analysis
- CO2 Sequestration and Geologic Interactions
- Crystallization and Solubility Studies
- Ocean Acidification Effects and Responses
- Marine Biology and Ecology Research
- Groundwater flow and contamination studies
- Methane Hydrates and Related Phenomena
- Marine and coastal ecosystems
- Hydrocarbon exploration and reservoir analysis
- Enhanced Oil Recovery Techniques
- Coral and Marine Ecosystems Studies
- Spectroscopy and Quantum Chemical Studies
- Clay minerals and soil interactions
- Marine and environmental studies
- Isotope Analysis in Ecology
- Heavy metals in environment
- Electrostatics and Colloid Interactions
- Metal Extraction and Bioleaching
Utrecht University
2013-2025
Imperial College London
2022-2024
Centre de Recherche et d’Enseignement de Géosciences de l’Environnement
2023
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2023
Institut de Recherche pour le Développement
2023
Centre National de la Recherche Scientifique
2023
University College London
2011-2016
Université Grenoble Alpes
2005-2009
Laboratoire des Écoulements Géophysiques et Industriels
2005
Minerals can precipitate from aqueous solutions via a fascinating variety of pathways. Classically, these pathways were thought to be initiated by single-step nucleation mechanism. Over the past two decades, several investigations revealed that minerals form through multi-step processes, dissolved single ions final stable crystal. Depending on mineral system under investigation and its environment, alternative mechanisms are possible, including ion-by-ion aggregation agglomeration clusters...
Synthetic Fe2+ monosulfide, FeSam, displays a disordered tetragonal mackinawite structure. It is nanocrystalline, with an average primary particle size equivalent to crystallite of 4 nm and corresponding specific surface area 350 m2/g. can be described in terms mixture two end-member phases different long-range ordering, which we refer as MkA MkB. has 2.2 × 1.7 lattice parameters = b 4.0 Å, c 6.6 ± 0.1 Å. MkB 7.4 2.9 3.7 5.5 0.2 A typical precipitate consist 30% 70% the proportion decreases...
The Charge Distribution MUltiSite Ion Complexation or CD–MUSIC modeling approach is used to describe the chemical structure of carbonate mineral-aqueous solution interfaces. new model extends existing surface complexation models minerals, by including atomic scale information on lattice and adsorbed water layer. In principle, can account for variable proportions face, edge kink sites exposed at mineral surface, formation inner- outer-sphere complexes. simulate development charges potentials...
Studies of phosphorus (P) dynamics in surface sediments lakes and coastal seas typically emphasize the role coupled iron (Fe), sulfur (S) P cycling for sediment burial release. Here, we show that anaerobic oxidation methane (AOM) also may impact such systems. Using porewater profiles sites an oligotrophic basin (Bothnian Sea), provide evidence formation Fe-bound (possibly vivianite; Fe3(PO4)2.8H2O) below zone AOM with sulfate. dissolved Fe2+ released from oxides is no longer scavenged by...
Calcite-water interactions are important not only in carbon sequestration and the global cycle, but also contaminant behaviour calcite-bearing host rock many industrial applications. Here we quantify effect of variations surface structure on calcite reactivity. Firstly, employ classical Molecular Dynamics simulations surfaces containing an etch pit a growth terrace, to show that local environment water around structurally different sites is distinct. In addition observing expected formation...
Abstract In the open ocean, calcium carbonates are mainly found in two mineral forms. Calcite, least soluble, is widespread at seafloor, while aragonite, more rarely preserved marine sediments. Despite its greater solubility, research has shown that whose contribution to global pelagic calcification could be par with of calcite, able reach deep-ocean. If large quantities aragonite settle and dissolve this represents a source alkalinity buffers deep ocean favours preservation less soluble...
Abstract. Salinity and temperature determine seawater density, differences in both thereby control global thermohaline circulation. Whereas numerous proxies have been calibrated applied to reconstruct temperature, a direct independent proxy for salinity is still missing. Ideally, new should target one of the constituents dissolved salt, such as [Na+] or [Cl−]. This study investigates impact on foraminiferal Na/Ca values by laser ablation ICP-MS analyses specimens benthic...
Although [Ni(S2CNBui2)2] is stable at high temperatures in a range of solvents, solvothermal decomposition occurs 145 °C oleylamine to give pure NiS nanoparticles, while n-hexylamine 120 mixture Ni3S4 (polydymite) and results. A combined experimental theoretical study gives mechanistic insight into the process can be used account for observed differences. Upon dissolution primary amine, octahedral trans-[Ni(S2CNBui2)2(RNH2)2] result as shown by situ XANES EXAFS confirmed DFT calculations....
The effects of pH and phosphate on the precipitation calcium carbonate polymorphs from aqueous solution were investigated. Experiments carried out at near-freezing temperature two different conditions (pH 13.4 9.0). At each condition, solutions having concentrations CaCl2 NaHCO3 mixed to achieve Ca/CO3 ratios 1:1 10:1 pumping rates with without phosphate. Results showed that, 13.4, only ikaite was formed, independent rate, ratio, 9.0, precipitate predominantly vaterite in absence presence...
Abstract. Expanding hypoxia in the Baltic Sea over past century has led to development of anoxic and sulfidic (euxinic) deep basins that are only periodically ventilated by inflows oxygenated waters from North Sea. In this study, we investigate potential consequences expanding for manganese (Mn) burial using a combination pore water sediment analyses dated cores eight locations. Diffusive fluxes dissolved Mn sediments overlying at oxic, hypoxic euxinic sites consistent with an active release...
Enhanced recycling of phosphorus as ocean deoxygenation expanded under past greenhouse climates contributed to widespread organic carbon burial and drawdown atmospheric CO 2 . Redox-dependent was more efficient in such ancient anoxic marine environments, compared modern settings, for reasons that remain unclear. Here, we show low rates apatite authigenesis organic-rich sediments can explain the amplified settings reflected highly elevated ratios total phosphorus. We argue may be partly...
FeS nucleation is generally more favourable in excess of sulphide compared to iron.
Abstract. A partition coefficient for copper (DCu) in foraminiferal calcite has been determined by culturing individuals of two benthic species under controlled laboratory conditions. The a trace element (TE) is an emperically relation between the TE/Ca ratio seawater and established many divalent cations. Despite its potential to act as tracer human-induced, heavy metal pollution, data not yet available copper. Since coefficients are usually function multiple factors (seawater temperature,...
It is becoming increasingly clear that the rate of crystal growth, even at constant saturation, varies with pH, ionic strength, and solution stoichiometry. Here, we contribute to limited data set on experimentally obtained calcite step velocities from solutions strictly controlled parameters. We measured growth obtuse acute edges in five Ca2+:CO32– activity ratios (r): 0.1, 1.0, 10, 25, 50, three saturation indices: SI = 0.6, 0.8, 1.0. The curve describing as a function r not centered 1,...
Abstract Carbon dioxide entering and acidifying the ocean can be neutralized by dissolution of calcium carbonate, which is mainly found in two mineral forms. Calcite more stable form often deep‐sea sediments, whilst aragonite soluble therefore rarely preserved. Recent research shows may account for a much larger portion marine carbonate export to interior via biological pump than previously thought, that does reach deep sea seafloor despite being buried. If present dissolving at it will...