Competitive adsorption of strontium and fulvic acid at the muscovite–solution interface observed with resonant anomalous X-ray reflectivity

Lee, Sang Soo; Park, Changyong; Fenter, Paul; Sturchio, Neil C.; Nagy, Kathryn L.

doi:10.1016/j.gca.2009.12.010

Cited by 48 publications

(77 citation statements)

References 60 publications

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“…Recent advances in surface-specific experimental techniques, such as sum frequency generation vibrational spectroscopy (SFG) [17], surface force apparatus (SFA) [28 -30], Fourier transform infrared spectroscopy (FTIR) [18], and synchrotron X-ray reflectivity [1,5,9,15,16,31] provide indispensable information on the structure of interfacial aqueous films. However, the results obtained from these experiments are often difficult to interpret on the molecular scale to quantify the underlying physico-chemical processes.…”

Section: Introductionmentioning

confidence: 99%

On the Hydrogen Bonding Structure at the Aqueous Interface of Ammonium-Substituted Mica: A Molecular Dynamics Simulation

Loganathan

2013

Zeitschrift Für Naturforschung A

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Dedicated to Professor Alfred Klemm on the occasion of his 100th birthday.Molecular dynamics (MD) computer simulations were performed for an aqueous film of 3 nm thickness adsorbed at the (001) surface of ammonium-substituted muscovite mica. The results provide a detailed picture of the near-surface structure and topological characteristics of the interfacial hydrogen bonding network. The effects of deuterium/hydrogen isotopic substitution in N(H/D) 4 + on the dynamics and consequently on the convergence of the structural properties have also been explored. Unlike many earlier simulations, a much larger surface area representing 72 crystallographic unit cells was used, which allowed for a more realistic representation of the substrate surface with a more disordered distribution of aluminium/silicon isomorphic substitutions in muscovite. The results clearly demonstrate that under ambient conditions both interfacial ammonium ions and the very first layer of water molecules are H-bonded only to the basal surface of muscovite, but do not form H-bonds with each other. As the distance from the surface increases, the H-bonds donated to the surface by both N(H/D) 4 + and H 2 O are gradually replaced by the H-bonds to the neighbouring water molecules, with the ammonia ions experiencing one reorientational transition region, while the H 2 O molecules experiencing three such distinct consecutive transitions. The hydrated N(H/D) 4 + ions adsorb almost exclusively as inner-sphere surface complexes with the preferential coordination to the basal bridging oxygen atoms surrounding the aluminium/silicon substitutions.

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Section: Introductionmentioning

confidence: 99%

On the Hydrogen Bonding Structure at the Aqueous Interface of Ammonium-Substituted Mica: A Molecular Dynamics Simulation

Loganathan

2013

Zeitschrift Für Naturforschung A

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“…Thus, the coating of HA on discrete inorganic colloids has been widely studied. Several adsorption mechanisms of HA on clay minerals have been proposed, such as ligand exchange, hydrophobic effects and electrostatic interaction (Arnarson & Keil, 2000;Chen, Koopal, Xiong, Avena, & Tan, 2017;Lee, Park, Fenter, Sturchio, & Nagy, 2010). Because HA in the aqueous phase tends to be both polydisperse and multifunctional, and minerals often have surfaces with different charge properties, several adsorption mechanisms may operate simultaneously (multimode adsorption).…”

Section: Highlightsmentioning

confidence: 99%

Selective adsorption of soil humic acid on binary systems containing kaolinite and goethite: Assessment of sorbent interactions

Chen

Koopal

et al. 2019

European J Soil Science

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Inorganic colloids are ubiquitous in soils and coexist as simple mixtures or as strong associations of particles. The coexisting inorganic colloids with a variety of active sites can selectively adsorb humic substances and thus affect the availability and mobility of organic matter. To investigate the selective adsorption of organic matter by coexisting inorganic colloids, humic acid (JGHA) extracted from soil, a kaolinite and goethite synthetic association (KGA) and a kaolinite and goethite mixture (KGM) were prepared and studied. With the adsorption expressed in μmol m−2, the adsorption affinity of JGHA on KGA (initial slope of isotherms) was slightly higher than that on KGM, although KGM could adsorb more JGHA molecules at larger JGHA concentrations. At pH 4, JGHA was adsorbed on the kaolinite edges and goethite through electrostatic attraction and ligand exchange, and on the kaolinite siloxane plates through hydrophobic interaction. At pH 6 and 8, the adsorption occurred only on the kaolinite siloxane plates and goethite. The overall average adsorption Gibbs energies were moderately negative, and comprised a strongly negative average overall molar entropy and a negative average overall molar entropy contribution. Thus, overall JGHA adsorption on KGA and KGM was enthalpy controlled. The large exothermic enthalpy gains and entropy losses were a result of electrostatic attraction and ligand exchange. The entropy gains because of hydrophobic attraction between JGHA and the kaolinite siloxane plates are masked by the larger entropy loss of adsorption on the hydrophilic surfaces. The fractions of JGHA with molar mass >~12.9 kDa (1 Da = 1 g mol−1) were adsorbed selectively by KGM, whereas the fractions <~12.9 kDa were selectively adsorbed by KGA. High molar mass and hydrophobic fractions adsorb selectively on the kaolinite siloxane plates, whereas low molar mass fractions with hydrophilic groups adsorb selectively on goethite and the kaolinite edges. Highlights Selective adsorption behaviour of HA on binary systems containing kaolinite and goethite. High molar mass and hydrophobic HA fractions selectively adsorb on kaolinite siloxane plates. Low molar mass and hydrophilic HA fractions selectively adsorb on kaolinite edges and goethite. Binding affinity of HA to KGA is stronger than to KGM; mineral associations are more beneficial for fixing OM in soil.

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“…While spectroscopic methods have been used to investigate the structure of NOM adsorbed on mineral surfaces [66][67][68][69][70][71][72][73][74], using simple organic acids as proxies for NOM can provide valuable insight into possible adsorption mechanisms [75,76]. Carboxylic functional groups are particularly relevant, not only to NOM but also as ligands responsible for binding and transporting potentially toxic elements, owing to many mineral surfaces carrying areas of net positive charge and poly-carboxylate species bridging between these surfaces and dissolved metals during flocculation processes.…”

Section: Experimental Studies Of Natural Organic Matter-mineral Strucmentioning

confidence: 99%

Interaction of Natural Organic Matter with Layered Minerals: Recent Developments in Computational Methods at the Nanoscale

2014

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Abstract:The role of mineral surfaces in the adsorption, transport, formation, and degradation of natural organic matter (NOM) in the biosphere remains an active research area owing to the difficulties in identifying proper working models of both NOM and mineral phases present in the environment. The variety of aqueous chemistries encountered in the subsurface (e.g., oxic vs. anoxic, variable pH) further complicate this field of study. Recently, the advent of nanoscale probes such as X-ray adsorption spectroscopy and surface vibrational spectroscopy applied to study such complicated interfacial systems have enabled new insight into NOM-mineral interfaces. Additionally, due to increasing capabilities in computational chemistry, it is now possible to simulate molecular processes of NOM at multiple scales, from quantum methods for electron transfer to classical methods for folding and adsorption of macroparticles. In this review, we present recent developments in interfacial properties of NOM adsorbed on mineral surfaces from a computational point of view that is informed by recent experiments.

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Competitive adsorption of strontium and fulvic acid at the muscovite–solution interface observed with resonant anomalous X-ray reflectivity

Cited by 48 publications

References 60 publications

On the Hydrogen Bonding Structure at the Aqueous Interface of Ammonium-Substituted Mica: A Molecular Dynamics Simulation

On the Hydrogen Bonding Structure at the Aqueous Interface of Ammonium-Substituted Mica: A Molecular Dynamics Simulation

Selective adsorption of soil humic acid on binary systems containing kaolinite and goethite: Assessment of sorbent interactions

Interaction of Natural Organic Matter with Layered Minerals: Recent Developments in Computational Methods at the Nanoscale

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