Simulating the pH and pCO2 Dependence of Uranium(VI) Adsorption by a Weathered Schist with Surface Complexation Models

2015 ◽  
pp. 61-86 ◽  
Author(s):  
James A. Davis ◽  
Timothy E. Payne ◽  
T. David Waite
Keyword(s):  
Surface Complexation

Interaction of cyclosporin A molecules with alkali and transition metal atoms on Cu(111)

2021 ◽  
Vol 57 (23) ◽  
pp. 2923-2926
Author(s):  
Yuanyuan Guo ◽  
Li Jiang ◽  
Ari Paavo Seitsonen ◽  
Bodong Zhang ◽  
Joachim Reichert ◽  
...  
Keyword(s):  
Transition Metal ◽  
Cyclosporin A ◽  
Surface Complexation ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Natural Peptide

Discriminatory on-surface complexation by the natural peptide CsA: up to two K atoms within its macrocycle, Co to residue 9 and the macrocycle, Fe non-selectively.

Ultrafast and highly capture of U(VI) by hierarchical mesoporous carbon

2020 ◽  
Vol 108 (9) ◽  
pp. 717-726 ◽  
Author(s):  
Han Guo ◽  
Ying Li ◽  
Huihui Wang ◽  
Ning Zhang ◽  
Alhadi Ishag ◽  
...  
Keyword(s):  
Mesoporous Carbon ◽  
Surface Complexation ◽  
Batch Adsorption ◽  
Layer Model ◽  
Environmental Cleanup ◽  
Triple Layer ◽  
High Efficient ◽  
Diffuse Layer Model ◽  
Capture Capacity ◽  
Inner Sphere Complexes

AbstractIn this study, the hierarchical mesoporous carbon (HMC) was synthesized by the hydrothermal method. The batch adsorption experiments showed that HMC exhibited the ultrafast equilibrium fate (80 % U(VI) capture efficiency within 5 min), high UO22+ capture capacity (210 mg/g, pH = 4.5) and well recyclability. The investigations of XPS techniques indicated the oxygen-containing functional groups were responsible for high efficient UO22+ adsorption. The pH-dependent adsorption was simulated by three surface complexation modellings, revealing that UO22+ adsorption on HMC was excellently fitted by triple layer model using two inner-sphere complexes (i. e. SOUO2+ and SOUO2(CO3)35− species) compared to constant capacitance model and diffuse layer model. These findings are crucial for expanding actual applications of HMC towards the removal of radionuclides under environmental cleanup.

Comparison of a Non Electrostatic Surface Complexation Model and Surface Phase Theories for Prediction of Future Sorption Properties.

2004 ◽  
Vol 824 ◽  
Author(s):  
Allan T. Emrén ◽  
Anna-Maria Jacobsson
Keyword(s):  
Aqueous Solution ◽  
Chemical Potential ◽  
Surface Complexation ◽  
Sorption Properties ◽  
Phase Method ◽  
Detailed Knowledge ◽  
Surface Phase ◽  
Surface Complexation Model ◽  
Advantages And Disadvantages ◽  
The One

AbstractIn performance assessments, sorption of radionuclides dissolved in groundwater is mostly handled by the use of fixed Kd values. It has been well known that this approach is unsatisfying. Only during the last few years, however, tools have become available that make it possible to predict the actual Kd value in an aqueous solution that differs from the one in which the sorption properties were measured.One such approach is surface complexation (SC) that gives a detailed knowledge of the sorption properties. In SC, one tries to find what kinds of sorbed species are available on the surface and the thermodynamics for their formation from species in the bulk aqueous solution. Recently, a different approach, surface phase method (SP), has been developed. In SP, a thin layer including the surface is treated as a separate phase. In the bulk aqueous solution, the surface phase is treated as a virtual component, and from the chemical potential of this component, the sorption properties can be found.In the paper, we compare advantages and disadvantages of the two kinds of models. We also investigate the differences in predicted sorption properties of a number of radionuclides (Co, Np, Th and U). Furthermore, we discuss under which circumstances, one approach or the other is preferable.

Measurements of Metal Adsorption in Oxide-Clay Mixtures: “Competitive-Additivity” Among Mixture Components

1992 ◽  
Vol 294 ◽  
Author(s):  
V. S. Tripathi ◽  
M.D. Siegel ◽  
Z. S. Kooner
Keyword(s):  
Surface Complexation ◽  
Particle Interactions ◽  
Complexation Constants ◽  
Lead Adsorption ◽  
Adsorption Sites ◽  
Adsorption Behaviors ◽  
Limited Success ◽  
Ph Dependent ◽  
Waste Repositories ◽  
Zinc Adsorption

ABSTRACTAn important question concerning the transport of radionuclides from nuclear waste repositories is whether the adsorption of metals by rocks and soils can be predicted from the properties of the constituent minerals. Attempts by previous researchers to use sorption models based on linear adsorption or weighted "sorptive additivity" have met with limited success. In this study, a “competitive-additivity” model based on surface complexation theory was used to model the pH-dependent adsorption of lead by goethite/Ca-montmorillonite mixtures using complexation constants obtained from single sorbent systems. Measurements of lead adsorption by goethite, Ca-montmorillonite, and goethite-Ca-montmorillonite mixtures (and similar studies of copper and zinc adsorption) demonstrate that the two adsorbents compete for adsorption of metals over wide ranges of pH and concentrations of adsorbents and metals. The adsorption behaviors of the mixtures are determined by the relative concentrations of the adsorbents and their respective affinities for the adsorbate metal. Particle-particle interactions such as heterocoagulation of the oxide and clay do not appear to be significant for the majority of the adsorption sites in this system.

Sorption Profile of Hg(II) onto Mixed Phase of Copper Sulphide and Copper Sulphate

2011 ◽  
Vol 356-360 ◽  
pp. 537-546
Author(s):  
Yow Loo Au Yoong ◽  
Pei Lay Yap ◽  
Muralithran G. Kutty ◽  
Olaf Timpe ◽  
Malte Behrens ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Copper Sulphate ◽  
Surface Complexation ◽  
Mixed Phase ◽  
Copper Sulphide ◽  
Reaction Parameters ◽  
Sorption Behaviour ◽  
Maximum Sorption Capacity ◽  
Maximum Sorption ◽  
Equilibrium Data

The use of surface oxidized covellite (CuS), namely mixed phase copper sulphide (CuS and CuSO4) was studied for the removal of mercury from aqueous solution under the effect of various reaction parameters (pH, time, Hg(II) concentration). From batch sorption studies, the equilibrium data revealed that the sorption behaviour of Hg(II) onto mixed phase copper sulphide follows well with Langmuir isotherm and the maximum sorption capacity (Qmax) determined ≈ 400mg Hg(II) /g of sorbent. Meanwhile, all the unreacted and reacted mixed phase copper sulphides were also characterized by Powder XRD, SEM and XPS techniques. The results indicated that the sorption of Hg(II) onto mixed phase copper sulphide occurs initially through the dissolution of surface oxidized CuSO4layer. After that, the surface complexation product formed and sorbed onto the surface of CuS. These outcomes suggest the potential ability of CuS in removing Hg(II) even if the CuS layer is being surrounded by oxidized layer of CuSO4.

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