DOI•
Studies of Mineral Nucleation and Growth Across Multiple Scales: Review of the Current State of Research Using the Example of Barite (BaSO4)
02 Nov 2021-
About: The article was published on 2021-11-02 and is currently open access. It has received 8 citations till now. The article focuses on the topics: Nucleation.
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TL;DR: In this paper , a coupling of pore-scale reactive transport modeling with the Arbitrary Lagrangian-Eulerian approach for tracking evolution of explicit solid interface during mineral precipitation is presented.
Abstract: A fundamental understanding of mineral precipitation kinetics relies largely on microscopic observations of the dynamics of mineral surfaces exposed to supersaturated solutions. Deconvolution of tightly bound transport, surface reaction, and crystal nucleation phenomena still remains one of the main challenges. Particularly, the influence of these processes on texture and morphology of mineral precipitate remains unclear. This study presents a coupling of pore-scale reactive transport modeling with the Arbitrary Lagrangian-Eulerian approach for tracking evolution of explicit solid interface during mineral precipitation. It incorporates a heterogeneous nucleation mechanism according to Classical Nucleation Theory which can be turned “on” or “off.” This approach allows us to demonstrate the role of nucleation on precipitate texture with a focus at micrometer scale. In this work precipitate formation is modeled on a 10 micrometer radius particle in reactive flow. The evolution of explicit interface accounts for the surface curvature which is crucial at this scale in the regime of emerging instabilities. The results illustrate how the surface reaction and reactive fluid flow affect the shape of precipitate on a solid particle. It is shown that nucleation promotes the formation of irregularly shaped precipitate and diminishes the effect of the flow on the asymmetry of precipitation around the particle. The observed differences in precipitate structure are expected to be an important benchmark for reaction-driven precipitation in natural environments.
4 citations
TL;DR: In this article , the nucleation and growth of barium sulfate in nanoporous silica was investigated using in situ small-angle X-ray scattering and Xray pair distribution function analysis, together with ex situ transmission and scanning transmission electron microscopy (TEM and STEM) imaging.
Abstract: The nucleation and growth of barium sulfate in nanoporous silica was investigated using in situ small-angle X-ray scattering and X-ray pair distribution function analysis, together with ex situ transmission and scanning transmission electron microscopy (TEM and STEM) imaging. We found that crystalline barite formation in micropores is likely preceded by a nonbulk barite phase in the nanopores, indicating a possible nonclassical nucleation pathway for barium sulfate under confinement. The nucleation of barium sulfate inside the nanopores stopped at ∼12% of the pores filled and was seemingly limited by the formation of crystals near the exterior of the silica particles, which likely blocked subsequent solute transport into the interior of the nanopores. The growth rate of barium sulfate was fit using the Johnson–Mehl–Avrami–Kolmogorov equation and constrained using a growth rate of barite of ∼1.0 × 10–7 mol/m2/s, obtained from previous studies, but is consistent with TEM and STEM observations made here. The inferred nucleation rate of barium sulfate inside nanopores is estimated to be on the order of 1.0 × 109 nuclei/m2/s, which is 2 orders of magnitude higher than previous measurements on a planar silica substrate (∼1.0 × 107 nuclei/m2/s). This implies that the ability of silica nanopores to promote barium sulfate nucleation is sufficiently high as to create a potentially self-limiting condition, where the nucleation reaction is shut down prematurely because rapid growth blocks reactant transport.
2 citations
TL;DR: In this paper , the authors observed synergistically enhanced uptake of lead and selenate on the barite surface through two sorption mechanisms: lattice incorporation and two-dimensional monolayer growth.
Abstract: The interactions of heavy metals with minerals influence the mobility and bioavailability of toxic elements in natural aqueous environments. The sorption of heavy metals on covalently bonded minerals is generally well described by surface complexation models (SCMs). However, understanding sorption on sparingly soluble minerals is challenging because of the dynamically evolving chemistry of sorbent surfaces. The interpretation can be even more complicated when multiple metal ions compete for sorption. In the present study, we observed synergistically enhanced uptake of lead and selenate on the barite (001) surface through two sorption mechanisms: lattice incorporation that dominates at lower coverages and two-dimensional monolayer growth that dominates at higher coverages. We also observed a systematic increase in the sorption affinity with increasing co-sorbed ion coverages, different from the assumption of invariant binding constants for individual adsorption processes in classical SCMs. Computational simulations showed thermodynamically favorable co-incorporation of lead and selenate by simultaneously substituting for barium and sulfate in neighboring sites, resulting in the formation of molecular clusters that locally match the net dimension of the substrate lattice. These results emphasize the importance of ion-ion interactions at mineral-water interfaces that control the fate and transport of contaminants in the environment.
1 citations
TL;DR: In this paper , Baclofen and Phenibut with dicarboxylic acid co-formers are discussed and the influence of different solution and milling environments during crystallization on the outcome is studied.
Abstract: Crystallization and multicomponent crystal formation of active pharmaceutical ingredients Baclofen and Phenibut with dicarboxylic acid co-formers are discussed. The crystallization process of several crystalline entities is elucidated via single crystal—as well as powder X-ray—diffraction, followed by thermal analysis and phase stability studies over time. Both APIs form increasingly complex crystalline phases with co-formers malic and tartaric acid, where phase purity of a desired compound is not necessarily a given. Therefore, the influence of different solution and milling environments during crystallization on the outcome is studied. Emphasis is laid on how molecular influences such as the chirality, propensity to form hydrates as well as low solubility of Baclofen and Phenibut impede attempts to gather high-quality single crystals. The results highlight that targeted crystallization of these compounds with dicarboxylic acids can be difficult and unreliable.
1 citations
TL;DR: Peters et al. as mentioned in this paper highlighted key research outputs across Dr. Peters' career, including mineralogical and morphological characterization of complex geomaterials, reactive transport of biogeochemical contaminants ranging from polycyclic aromatic hydrocarbons to arsenic and strontium, and reactive evolution of fractured and porous media.
Abstract: Dr. Catherine A. Peters’ research has advanced various topics in hydro-biogeochemistry. This paper highlights key research outputs across Dr. Peters’ career. Throughout her research endeavors, Dr. Peters has distinguished herself and her research portfolio via integration of experimental, theoretical and modeling approaches to tackle research questions at the intersection of hydrology and environmental geochemistry. Her work encompasses topics from mineralogical and morphological characterization of complex geomaterials, reactive transport of biogeochemical contaminants ranging from polycyclic aromatic hydrocarbons to arsenic and strontium, and reactive evolution of fractured and porous media with chemical and physical heterogeneities. Her work has advanced our fundamental understanding of complex geochemical reactions and their impacts on fracture alteration, the fate and transport of contaminants, and the stability of subsurface energy and resources systems. These findings have helped inform applications regarding bio-remediation, heavy metal removal by mineralization, and geological carbon storage. The methods and findings showcased here have broad scientific and engineering impacts and have benefitted other emerging research topics in hydrology and related topics (e.g., Earth’s critical zone). Along her scientific journey, Dr. Peters has uplifted and empowered many graduate and undergraduate students with her kindness, encouragement, and confidence in them. These students are now at different stages of their scientific careers and are following her steps in nurturing the next generation of scientists with diverse backgrounds in various types of institutions.
1 citations
References
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TL;DR: High-resolution transmission electron microscopy of biomineralization products of iron-oxidizing bacteria revealed an alternative coarsening mechanism in which adjacent 2- to 3-nanometer particles aggregate and rotate so their structures adopt parallel orientations in three dimensions.
Abstract: Crystals are generally considered to grow by attachment of ions to inorganic surfaces or organic templates. High-resolution transmission electron microscopy of biomineralization products of iron-oxidizing bacteria revealed an alternative coarsening mechanism in which adjacent 2- to 3-nanometer particles aggregate and rotate so their structures adopt parallel orientations in three dimensions. Crystal growth is accomplished by eliminating water molecules at interfaces and forming iron-oxygen bonds. Self-assembly occurs at multiple sites, leading to a coarser, polycrystalline material. Point defects (from surface-adsorbed impurities), dislocations, and slabs of structurally distinct material are created as a consequence of this growth mechanism and can dramatically impact subsequent reactivity.
1,620 citations
Pacific Northwest National Laboratory1, University of Washington2, University of Wisconsin-Madison3, Radcliffe Institute for Advanced Study4, Eindhoven University of Technology5, University of Minnesota6, Lawrence Berkeley National Laboratory7, Northwestern University8, University of California, Berkeley9, University of Houston10, University of California, Davis11, University of Delaware12, Virginia Tech13, University of Leeds14, University of Konstanz15
TL;DR: The current understanding of CPA is described, some of the nonclassical thermodynamic and dynamic mechanisms known to give rise to experimentally observed pathways are examined, and the challenges to the understanding of these mechanisms are highlighted.
Abstract: Field and laboratory observations show that crystals commonly form by the addition and attachment of particles that range from multi-ion complexes to fully formed nanoparticles. The particles involved in these nonclassical pathways to crystallization are diverse, in contrast to classical models that consider only the addition of monomeric chemical species. We review progress toward understanding crystal growth by particle-attachment processes and show that multiple pathways result from the interplay of free-energy landscapes and reaction dynamics. Much remains unknown about the fundamental aspects, particularly the relationships between solution structure, interfacial forces, and particle motion. Developing a predictive description that connects molecular details to ensemble behavior will require revisiting long-standing interpretations of crystal formation in synthetic systems, biominerals, and patterns of mineralization in natural environments.
1,357 citations
TL;DR: It is demonstrated that dissolved calcium carbonate in fact contains stable prenucleation ion clusters forming even in undersaturated solution, and specified complex crystal structures challenge the classical view on nucleation considering the formation of metastable ion clusters.
Abstract: Calcium carbonate forms scales, geological deposits, biominerals, and ocean sediments. Huge amounts of carbon dioxide are retained as carbonate ions, and calcium ions represent a major contribution to water hardness. Despite its relevance, little is known about the precipitation mechanism of calcium carbonate, and specified complex crystal structures challenge the classical view on nucleation considering the formation of metastable ion clusters. We demonstrate that dissolved calcium carbonate in fact contains stable prenucleation ion clusters forming even in undersaturated solution. The cluster formation can be characterized by means of equilibrium thermodynamics, applying a multiple-binding model, which allows for structural preformation. Stable clusters are the relevant species in calcium carbonate nucleation. Such mechanisms may also be important for the crystallization of other minerals.
1,304 citations
TL;DR: Improved understanding of the fate and transport of contaminants of concern and increased long-term monitoring and data dissemination will help effectively manage water-quality risks associated with unconventional gas industry today and in the future.
Abstract: Unconventional natural gas resources offer an opportunity to access a relatively clean fossil fuel that could potentially lead to energy independence for some countries. Horizontal drilling and hydraulic fracturing make the extraction of tightly bound natural gas from shale formations economically feasible. These technologies are not free from environmental risks, however, especially those related to regional water quality, such as gas migration, contaminant transport through induced and natural fractures, wastewater discharge, and accidental spills. We review the current understanding of environmental issues associated with unconventional gas extraction. Improved understanding of the fate and transport of contaminants of concern and increased long-term monitoring and data dissemination will help manage these water-quality risks today and in the future.
1,263 citations
TL;DR: Analysis of published data reveals evidence for stray gas contamination, surface water impacts in areas of intensive shale gas development, and the accumulation of radium isotopes in some disposal and spill sites.
Abstract: The rapid rise of shale gas development through horizontal drilling and high volume hydraulic fracturing has expanded the extraction of hydrocarbon resources in the U.S. The rise of shale gas development has triggered an intense public debate regarding the potential environmental and human health effects from hydraulic fracturing. This paper provides a critical review of the potential risks that shale gas operations pose to water resources, with an emphasis on case studies mostly from the U.S. Four potential risks for water resources are identified: (1) the contamination of shallow aquifers with fugitive hydrocarbon gases (i.e., stray gas contamination), which can also potentially lead to the salinization of shallow groundwater through leaking natural gas wells and subsurface flow; (2) the contamination of surface water and shallow groundwater from spills, leaks, and/or the disposal of inadequately treated shale gas wastewater; (3) the accumulation of toxic and radioactive elements in soil or stream sediments near disposal or spill sites; and (4) the overextraction of water resources for high-volume hydraulic fracturing that could induce water shortages or conflicts with other water users, particularly in water-scarce areas. Analysis of published data (through January 2014) reveals evidence for stray gas contamination, surface water impacts in areas of intensive shale gas development, and the accumulation of radium isotopes in some disposal and spill sites. The direct contamination of shallow groundwater from hydraulic fracturing fluids and deep formation waters by hydraulic fracturing itself, however, remains controversial.
1,255 citations