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Showing 1 to 20 of 33 for “"Surface Complexation"”.
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Organic-inorganic hybrid materials for arsenic adsorption : surface complexation and intraparticle diffusion
… under different pH conditions, respectively. Surface complexation models (SCM) can be developed to simulate the adsorption performance as a function of pH, arsenic concentrations, and ionic strength. And estimation of important adsorption parameters such as surface site density, and adsorption …
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Surface complexation modeling of Pb(II), Cd(II) and Se(IV) onto iron hydroxides in single and bisolute systems
… fate and transport of metal ion contaminants in surface and groundwaters. Surface Complexation Models (SCMs) have emerged as the most promising tools for predicting contaminant ion sorption to iron (hydr)oxides. The reliability of SCMs is highly dependent on the ability to select appropriate …
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Application of surface complexation modeling to the adsorption of uranium(VI) onto hematite in the presence of humic and fulvic acids, The
Includes bibliographical references (pages 154-160).
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The adsorption of Ni, Cu, Zn, Cd and Pb by δ-MnO₂ and its inclusion in an equilibrium model of metal partitioning in soils
… models of metal fate in soil systems. Surface complexation properties of a synthetic manganese dioxide were investigated using glass electrode potentiometry. Experimental data were interpreted according to the surface complexation model in conjunction with the diffuse double layer model …
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Effects of phytic acid sorption on iron polymerization and at the ferrihydrite-water interface
… groups of phytic acid contribute to the surface complexation and/or precipitation processes. In this study, sorption behavior of phytic acid in ferrihydrite was examined using experimental geochemistry, solution 31P nuclear magnetic resonance spectroscopy, X-ray diffraction and scanning …
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Geochemical Behavior of the Rare Earth Elements in Natural Terrestrial Waters
… the geochemical behavior of REEs: (1) solution complexation of REEs with both inorganic and organic ligands in natural terrestrial waters; (2) the geochemical behavior of REEs along the groundwater flow paths in two different aquifer types (i.e., sand vs. carbonate); and (3) surface complexation …
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Interaction of aqueous U(VI) with goethite, montmorillonite, and UO2(s)
<p>Uranium contamination in subsurface environments is a matter of great concern throughout the world. Fate and transport of uranium in the subsurface can be controlled by U(VI) adsorption and reduction onto common iron (oxy)hydroxides and clay minerals. Aqueous U(VI) can also exchange uranium …
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The design, synthesis and characterization of polynuclear materials for applications for catalysis
… and iminophosphine functionalities on the surface. Complexation reactions with [PdCl2(COD)] and [RhCl(CO)2]2 gave the corresponding chitosan-supported complexes (2.5-2.8) and (2.13-2.14). These metal-containing materials and their precursors were isolated as air and moisture stable solids …
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Coupled arsenic, iron, and nitrogen cycling in arsenic-contaminated Upper Mystic Lake
… laboratory studies, and applied mass balance, surface complexation, and thermodynamic modeling to explore As cycling and its links to other elemental cycles (Fe, N, 02) in UML. Nitrate appears to control iron (Fe) and As cycling in the hypolimion of urban, eutrophic UML. In doing so, nitrate …
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Surface Sorption Properties of Halophilic Archaea
… elemental cycling, metal transport in near-surface water-rock systems, sedimentary diagenesis, and soil formation. Archaea are ubiquitous in near-surface water-rock systems and numerous laboratory and field studies have demonstrated that Archaea can facilitate the formation and dissolution …
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Individual and competitive adsorption of MSMA and phosphate onto iron and non-iron soil
… were strongly influenced by pH indicating that surface complexation on amphoteric sorption sites in the soil was responsible for MSMA (V) adsorption.
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Numerical Solution Techniques for Reaction Parameter Sensitivity Coefficients in Multicomponent Subsurface Transport Models
… uranium-quartz system with mass transfer-limited surface complexation reactions. The computed sensitivity coefficients are used to gain insight into the relative significance of reaction processes and to rank individual reaction parameters in terms of importance. Sensitivity coefficients are also …
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Adsorption and co-precipitation of heavy metals on hydrous ferric oxides (HFO) from acidic waters
… computer model PHRHEQC and laboratory-derived complexation constants (K) were used to predict the amount of heavy metals that should be adsorbed on HFO. The predicted values are generally 1 to 2 orders of magnitude greater than measured values. This difference may be due to organic complexation …
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Pore-scale processes : quantification of the controls on the transport of Ra and Cr, and development of a novel geochemical visualization tool
… sorption to minerals and organic matter, and complexation with ligands in solution. Depending on the contaminant of interest, the importance of these different processes will widely vary, and the natural heterogeneity of soil systems all further frustrate modeling of contaminant transport. …
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Contributions to predicting contaminant leaching from secondary materials used in roads
… by Pb(VO4)3 solubility at low pHs and by surface precipitation reactions at high pHs. Leaching of Cd and Zn were controlled by surface complexation and surface precipitation, respectively.</p>
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Application of phosphate and surfactant-modified zeolite for remediation/attenuation of trace elements in soil and coal fly ash
… leachate after SMZ treatment. Batch experiments, surface complexation modeling, and X-ray spectroscopic tools were used to elucidate the kinetics and mechanisms of arsenate (As(V)) and phosphate (Pi) adsorption on ferric hydroxide. Both oxyanions showed similar adsorptions during single-ion …
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Investigating Bisulfide Sorption onto Bentonite through Laboratory Experiments and Numerical Modelling
… through the bentonite buffer to the UFC surface. HS- sorption onto bentonite can reduce the corrosion risk, but its dynamics are not yet well-understood, especially in DGR environments. Hence, this study offers a comprehensive insight into HS- sorption process onto bentonite through …
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Aqueous Silica in the Environment: Effects on Iron Hydroxide Surface Chemistry and Implications for Natural and Engineered Systems
… waters and exhibits a high affinity for the surfaces of iron oxides. Therefore, it is expected to play an important role in environmental systems. Experiments were conducted to investigate the fundamentals of silica sorption onto pre-formed ferric hydroxide at pH 5.0-9.5 and silica …
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The sorption of uranium(VI) and neptunium(V) onto surfaces of selected metal oxides and alumosilicates studied by in situ vibrational spectroscopy
… molecular phenomena such as hydrolysis and complexation reactions in aqueous solutions as well as the diffusion and sorption onto minerals present along groundwater flow paths. These reactions significantly influence the mobility and bioavailability of the metal ions in the environment, in …
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Interaction of fluroquinolone antibiotics with nanophase metal oxide photocatalysts and soil minerals
The contamination of surface waters with pharmaceutical compounds has been recognized as a problem in many regions of the world. These xenobiotic compounds originate from point sources, such as treated wastewater effluent, and also from non-point sources, such as runoff from animal rearing …
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