1
|
Ge Y, Zhu S, Wang K, Liu F, Zhang S, Wang R, Ho SH, Chang JS. One-step synthesis of a core-shell structured biochar using algae (Chlorella) powder and ferric sulfate for immobilizing Hg(II). JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133991. [PMID: 38492405 DOI: 10.1016/j.jhazmat.2024.133991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/06/2024] [Accepted: 03/06/2024] [Indexed: 03/18/2024]
Abstract
Mercury (Hg) pollution poses a significant environmental challenge. One promising method for its removal is the sorption of mercuric ions using biochar. FeS-doped biochar (FBC) exhibits effective mercury adsorption, however may release excess iron into the surrounding water. To address this issue, a novel magnetic pyrrhotite/magnetite-doped biochar with a core-shell structure was synthesized for the adsorption of 2-valent mercury (Hg(II)). The proposed synthesis process involved the use of algae powder and ferric sulfate in a one-step method. By varying the ratio of ferric sulfate and alga powder (within the range of 0.18 - 2.5) had a notable impact on the composition of FBC. As the ferric sulfate content increased, the FBC exhibited a higher concentration of oxygen-containing groups. To assess the adsorption capacity, Langmuir and Freundlich adsorption models were applied to the experimental data. The most effective adsorption was achieved with FBC-4, reaching a maximum capacity (Qm) of 95.51 mg/g. In particular, at low Hg(II) concentrations, FBC-5 demonstrated the ability to reduce Hg(II) concentrations to less than 0.05 mg/L within 30 min. Additionally, the stability of FBC was confirmed within the pH range of 3.8 - 7.2. The study also introduced a model to analyze the adsorption preference for different Hg(II) species. Calomel was identified in the mercury saturated FBC, whereas the core-shell structure exhibited excellent conductivity, which most likely contributed to the minimal release of iron. In summary, this research presents a novel and promising method for synthesizing core-shell structured biochar and provides a novel approach to explore the adsorption contribution of different metal species.
Collapse
Affiliation(s)
- Yiming Ge
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Shishu Zhu
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China
| | - Ke Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Feiyu Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Shiyu Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Rupeng Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Shih-Hsin Ho
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
| | - Jo-Shu Chang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China; Department of Chemical and Materials Engineering, College of Engineering, Tunghai University, Taichung, Taiwan; Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan; Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li, Taiwan.
| |
Collapse
|
2
|
Tsikas D. GC-MS Studies on Nitric Oxide Autoxidation and S-Nitrosothiol Hydrolysis to Nitrite in pH-Neutral Aqueous Buffers: Definite Results Using 15N and 18O Isotopes. Molecules 2023; 28:molecules28114281. [PMID: 37298756 DOI: 10.3390/molecules28114281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/19/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
Nitrite (O=N-O-, NO2-) and nitrate (O=N(O)-O-, NO3-) are ubiquitous in nature. In aerated aqueous solutions, nitrite is considered the major autoxidation product of nitric oxide (●NO). ●NO is an environmental gas but is also endogenously produced from the amino acid L-arginine by the catalytic action of ●NO synthases. It is considered that the autoxidation of ●NO in aqueous solutions and in O2-containing gas phase proceeds via different neutral (e.g., O=N-O-N=O) and radical (e.g., ONOO●) intermediates. In aqueous buffers, endogenous S-nitrosothiols (thionitrites, RSNO) from thiols (RSH) such as L-cysteine (i.e., S-nitroso-L-cysteine, CysSNO) and cysteine-containing peptides such as glutathione (GSH) (i.e., S-nitrosoglutathione, GSNO) may be formed during the autoxidation of ●NO in the presence of thiols and dioxygen (e.g., GSH + O=N-O-N=O → GSNO + O=N-O- + H+; pKaHONO, 3.24). The reaction products of thionitrites in aerated aqueous solutions may be different from those of ●NO. This work describes in vitro GC-MS studies on the reactions of unlabeled (14NO2-) and labeled nitrite (15NO2-) and RSNO (RS15NO, RS15N18O) performed in pH-neutral aqueous buffers of phosphate or tris(hydroxyethylamine) prepared in unlabeled (H216O) or labeled H2O (H218O). Unlabeled and stable-isotope-labeled nitrite and nitrate species were measured by gas chromatography-mass spectrometry (GC-MS) after derivatization with pentafluorobenzyl bromide and negative-ion chemical ionization. The study provides strong indication for the formation of O=N-O-N=O as an intermediate of ●NO autoxidation in pH-neutral aqueous buffers. In high molar excess, HgCl2 accelerates and increases RSNO hydrolysis to nitrite, thereby incorporating 18O from H218O into the SNO group. In aqueous buffers prepared in H218O, synthetic peroxynitrite (ONOO-) decomposes to nitrite without 18O incorporation, indicating water-independent decomposition of peroxynitrite to nitrite. Use of RS15NO and H218O in combination with GC-MS allows generation of definite results and elucidation of reaction mechanisms of oxidation of ●NO and hydrolysis of RSNO.
Collapse
Affiliation(s)
- Dimitrios Tsikas
- Core Unit Proteomics, Institute of Toxicology, Hannover Medical School, 30625 Hannover, Germany
| |
Collapse
|
3
|
Sartori A, Giri RP, Fujii H, Hövelmann SC, Warias JE, Jordt P, Shen C, Murphy BM, Magnussen OM. Role of chemisorbing species in growth at liquid metal-electrolyte interfaces revealed by in situ X-ray scattering. Nat Commun 2022; 13:5421. [PMID: 36109498 PMCID: PMC9477831 DOI: 10.1038/s41467-022-32932-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/22/2022] [Indexed: 11/22/2022] Open
Abstract
Liquid-liquid interfaces offer intriguing possibilities for nanomaterials growth. Here, fundamental interface-related mechanisms that control the growth behavior in these systems are studied for Pb halide formation at the interface between NaX + PbX2 (X = F, Cl, Br) and liquid Hg electrodes using in situ X-ray scattering and complementary electrochemical and microscopy measurements. These studies reveal a decisive role of the halide species in nucleation and growth of these compounds. In Cl- and Br-containing solution, deposition starts by rapid formation of well-defined ultrathin (∼7 Å) precursor adlayers, which provide a structural template for the subsequent quasi-epitaxial growth of c-axis oriented Pb(OH)X bulk crystals. In contrast, growth in F-containing solution proceeds by slow formation of a more disordered deposit, resulting in random bulk crystal orientations on the Hg surface. These differences can be assigned to the interface chemistry, specifically halide chemisorption, which steers the formation of these highly textured deposits at the liquid-liquid interface. Growth at liquid-liquid interfaces differ inherently from that on solids, making it attractive for nanomaterial formation. Here, the authors use X-ray scattering to derive a detailed microscopic picture of lead-halide growth on liquid mercury that reveals the key importance of anion adsorption.
Collapse
|
4
|
Li C, Wang Y. A Combination Method of Quantum Chemistry and Its Application to the Study of the Effects of Mercury on the Formation of Sulfuric Acid Aerosol. ACTA CHIMICA SINICA 2021. [DOI: 10.6023/a21040147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
5
|
Amaro-Estrada JI, Hernández-Cobos J, Saint-Martin H, Maron L, Ramírez-Solís A. Hydration of CH3HgOH and CH3HgCl compared to HgCl2, HgClOH, and Hg(OH)2: A DFT microsolvation cluster approach. J Chem Phys 2018; 149:144301. [DOI: 10.1063/1.5038418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | | | | | - Laurent Maron
- Université de Toulouse, INSA Laboratoire de Physicochimie de Nano-Objets, 135 Avenue de Rangueil, F31077 Toulouse, France
| | - Alejandro Ramírez-Solís
- Depto. de Física, Centro de Investigación en Ciencias-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209, Mexico
| |
Collapse
|
6
|
León-Pimentel CI, Amaro-Estrada JI, Hernández-Cobos J, Saint-Martin H, Ramírez-Solís A. Aqueous solvation of Mg(ii) and Ca(ii): A Born-Oppenheimer molecular dynamics study of microhydrated gas phase clusters. J Chem Phys 2018; 148:144307. [PMID: 29655339 DOI: 10.1063/1.5021348] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The hydration features of [Mg(H2O)n]2+ and [Ca(H2O)n]2+ clusters with n = 3-6, 8, 18, and 27 were studied by means of Born-Oppenheimer molecular dynamics simulations at the B3LYP/6-31+G** level of theory. For both ions, it is energetically more favorable to have all water molecules in the first hydration shell when n ≤ 6, but stable lower coordination average structures with one water molecule not directly interacting with the ion were found for Mg2+ at room temperature, showing signatures of proton transfer events for the smaller cation but not for the larger one. A more rigid octahedral-type structure for Mg2+ than for Ca2+ was observed in all simulations, with no exchange of water molecules to the second hydration shell. Significant thermal effects on the average structure of clusters were found: while static optimizations lead to compact, spherically symmetric hydration geometries, the effects introduced by finite-temperature dynamics yield more prolate configurations. The calculated vibrational spectra are in agreement with infrared spectroscopy results. Previous studies proposed an increase in the coordination number (CN) from six to eight water molecules for [Ca(H2O)n]2+ clusters when n ≥ 12; however, in agreement with recent measurements of binding energies, no transition to a larger CN was found when n > 8. Moreover, the excellent agreement found between the calculated extended X-ray absorption fine structure spectroscopy spectra for the larger cluster and the experimental data of the aqueous solution supports a CN of six for Ca2+.
Collapse
Affiliation(s)
- C I León-Pimentel
- Instituto de Ciencias Físicas, Universidad Autónoma de México, Apdo. Postal 48-3, Cuernavaca, Morelos 62251, Mexico
| | - J I Amaro-Estrada
- Instituto de Ciencias Físicas, Universidad Autónoma de México, Apdo. Postal 48-3, Cuernavaca, Morelos 62251, Mexico
| | - J Hernández-Cobos
- Instituto de Ciencias Físicas, Universidad Autónoma de México, Apdo. Postal 48-3, Cuernavaca, Morelos 62251, Mexico
| | - H Saint-Martin
- Instituto de Ciencias Físicas, Universidad Autónoma de México, Apdo. Postal 48-3, Cuernavaca, Morelos 62251, Mexico
| | - A Ramírez-Solís
- Departamento de Física, Centro de Investigación en Ciencias, IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209, Mexico
| |
Collapse
|
7
|
Ramírez-Solís A, Amaro-Estrada JI, León-Pimentel CI, Hernández-Cobos J, Garrido-Hoyos SE, Saint-Martin H. On the aqueous solvation of AsO(OH)3vs. As(OH)3. Born–Oppenheimer molecular dynamics density functional theory cluster studies. Phys Chem Chem Phys 2018; 20:16568-16578. [DOI: 10.1039/c8cp01673a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BOMD simulations were used to reveal the hydration features of As(OH)3 and (for the first time) AsO(OH)3 in aqueous solution.
Collapse
Affiliation(s)
- A. Ramírez-Solís
- Depto. de Física
- Centro de Investigación en Ciencias, IICBA
- Universidad Autónoma del Estado de Morelos
- Cuernavaca
- Mexico
| | - J. I. Amaro-Estrada
- Instituto de Ciencias Físicas
- Universidad Nacional Autónoma de México
- Cuernavaca
- Mexico
| | - C. I. León-Pimentel
- Instituto de Ciencias Físicas
- Universidad Nacional Autónoma de México
- Cuernavaca
- Mexico
| | - J. Hernández-Cobos
- Instituto de Ciencias Físicas
- Universidad Nacional Autónoma de México
- Cuernavaca
- Mexico
| | | | - H. Saint-Martin
- Instituto de Ciencias Físicas
- Universidad Nacional Autónoma de México
- Cuernavaca
- Mexico
| |
Collapse
|
8
|
Hodel FH, Deglmann P, Luber S. Exploring Solvation Effects in Ligand-Exchange Reactions via Static and Dynamic Methods. J Chem Theory Comput 2017; 13:3348-3358. [DOI: 10.1021/acs.jctc.7b00214] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Florian H. Hodel
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Peter Deglmann
- BASF SE, Carl-Bosch-Straße
38, 67056 Ludwigshafen
am Rhein, Germany
| | - Sandra Luber
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| |
Collapse
|
9
|
Manceau A, Enescu M, Simionovici A, Lanson M, Gonzalez-Rey M, Rovezzi M, Tucoulou R, Glatzel P, Nagy KL, Bourdineaud JP. Chemical Forms of Mercury in Human Hair Reveal Sources of Exposure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10721-10729. [PMID: 27676331 DOI: 10.1021/acs.est.6b03468] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Humans are contaminated by mercury in different forms from different sources. In practice, contamination by methylmercury from fish consumption is assessed by measuring hair mercury concentration, whereas exposure to elemental and inorganic mercury from other sources is tested by analysis of blood or urine. Here, we show that diverse sources of hair mercury at concentrations as low as 0.5 ppm can be individually identified by specific coordination to C, N, and S ligands with high energy-resolution X-ray absorption spectroscopy. Methylmercury from seafood, ethylmercury used as a bactericide, inorganic mercury from dental amalgams, and exogenously derived atmospheric mercury bind in distinctive intermolecular configurations to hair proteins, as supported by molecular modeling. A mercury spike located by X-ray nanofluorescence on one hair strand could even be dated to removal of a single dental amalgam. Chemical forms of other known or putative toxic metals in human tissues could be identified by this approach with potential broader applications to forensic, energy, and materials science.
Collapse
Affiliation(s)
- Alain Manceau
- ISTerre, Université Grenoble Alpes, CNRS, CS 40700, 38058 Grenoble, France
| | - Mironel Enescu
- Laboratoire Chrono Environnement, Université de Franche-Comté, CNRS , 25030 Besançon, France
| | | | - Martine Lanson
- ISTerre, Université Grenoble Alpes, CNRS, CS 40700, 38058 Grenoble, France
| | | | - Mauro Rovezzi
- European Synchrotron Radiation Facility (ESRF), 71 Rue des Martyrs, 38000 Grenoble, France
| | - Rémi Tucoulou
- European Synchrotron Radiation Facility (ESRF), 71 Rue des Martyrs, 38000 Grenoble, France
| | - Pieter Glatzel
- European Synchrotron Radiation Facility (ESRF), 71 Rue des Martyrs, 38000 Grenoble, France
| | - Kathryn L Nagy
- Department of Earth and Environmental Sciences, MC-186, 845 West Taylor Street, University of Illinois at Chicago , Chicago, Illinois 60607, United States
| | - Jean-Paul Bourdineaud
- Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS , 2 rue Escarpit, 33607 Pessac, France
| |
Collapse
|
10
|
Manceau A, Lemouchi C, Rovezzi M, Lanson M, Glatzel P, Nagy KL, Gautier-Luneau I, Joly Y, Enescu M. Structure, Bonding, and Stability of Mercury Complexes with Thiolate and Thioether Ligands from High-Resolution XANES Spectroscopy and First-Principles Calculations. Inorg Chem 2015; 54:11776-91. [DOI: 10.1021/acs.inorgchem.5b01932] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Mauro Rovezzi
- European Synchrotron Radiation Facility (ESRF), 71 Rue des Martyrs, 38000 Grenoble, France
| | | | - Pieter Glatzel
- European Synchrotron Radiation Facility (ESRF), 71 Rue des Martyrs, 38000 Grenoble, France
| | - Kathryn L. Nagy
- Department of Earth and Environmental Sciences, University of Illinois at Chicago, MC-186, 845 West Taylor Street, Chicago, Illinois 60607, United States
| | | | | | - Mironel Enescu
- Laboratoire
Chrono Environnement, Université de Franche-Comté, CNRS, 25030 Besançon, France
| |
Collapse
|
11
|
Manceau A, Lemouchi C, Enescu M, Gaillot AC, Lanson M, Magnin V, Glatzel P, Poulin BA, Ryan JN, Aiken GR, Gautier-Luneau I, Nagy KL. Formation of Mercury Sulfide from Hg(II)-Thiolate Complexes in Natural Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:9787-9796. [PMID: 26168020 DOI: 10.1021/acs.est.5b02522] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Methylmercury is the environmental form of neurotoxic mercury that is biomagnified in the food chain. Methylation rates are reduced when the metal is sequestered in crystalline mercury sulfides or bound to thiol groups in macromolecular natural organic matter. Mercury sulfide minerals are known to nucleate in anoxic zones, by reaction of the thiol-bound mercury with biogenic sulfide, but not in oxic environments. We present experimental evidence that mercury sulfide forms from thiol-bound mercury alone in aqueous dark systems in contact with air. The maximum amount of nanoparticulate mercury sulfide relative to thiol-bound mercury obtained by reacting dissolved mercury and soil organic matter matches that detected in the organic horizon of a contaminated soil situated downstream from Oak Ridge, TN, in the United States. The nearly identical ratios of the two forms of mercury in field and experimental systems suggest a common reaction mechanism for nucleating the mineral. We identified a chemical reaction mechanism that is thermodynamically favorable in which thiol-bound mercury polymerizes to mercury-sulfur clusters. The clusters form by elimination of sulfur from the thiol complexes via breaking of mercury-sulfur bonds as in an alkylation reaction. Addition of sulfide is not required. This nucleation mechanism provides one explanation for how mercury may be immobilized, and eventually sequestered, in oxygenated surface environments.
Collapse
Affiliation(s)
- Alain Manceau
- †ISTerre, Université Grenoble Alpes, CNRS, 38000 Grenoble, France
| | - Cyprien Lemouchi
- †ISTerre, Université Grenoble Alpes, CNRS, 38000 Grenoble, France
- ‡Institut Néel, Université Grenoble Alpes, CNRS, 38000 Grenoble, France
| | - Mironel Enescu
- §Laboratoire Chrono Environnement, Université de Franche-Comté, CNRS, 25030 Besançon, France
| | - Anne-Claire Gaillot
- ∥Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 Rue de la Houssinière, 44322 Nantes, France
| | - Martine Lanson
- †ISTerre, Université Grenoble Alpes, CNRS, 38000 Grenoble, France
| | - Valérie Magnin
- †ISTerre, Université Grenoble Alpes, CNRS, 38000 Grenoble, France
| | - Pieter Glatzel
- ⊥European Synchrotron Radiation Facility (ESRF), 71 Rue des Martyrs, 38000 Grenoble, France
| | - Brett A Poulin
- #Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 428 UCB, Boulder, Colorado 80309-0428, United States
- ∇U.S. Geological Survey, 3215 Marine Street, Boulder, Colorado 80303, United States
| | - Joseph N Ryan
- #Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 428 UCB, Boulder, Colorado 80309-0428, United States
| | - George R Aiken
- ∇U.S. Geological Survey, 3215 Marine Street, Boulder, Colorado 80303, United States
| | | | - Kathryn L Nagy
- @Department of Earth and Environmental Sciences, University of Illinois at Chicago, MC-186, 845 West Taylor Street, Chicago, Illinois 60607, United States
| |
Collapse
|
12
|
Ramírez-Solís A, Maron L. Aqueous microsolvation of CdCl₂: density functional theory and Born-Oppenheimer molecular dynamics studies. J Chem Phys 2014; 141:094304. [PMID: 25194369 DOI: 10.1063/1.4894286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report a systematic study of aqueous microsolvation of CdCl2. The optimized structures and binding energies of the CdCl2-(H2O)n clusters with n = 1-24 have been computed at the B3PW91/6-31G** level. The solvation patterns obtained at the DFT level are verified at the MP2/AVTZ level for n < 6. Unlike HgCl2-(H2O)n case, where there are at most three Hg-O(w) orbital interactions, Cd also establishes four equatorial orbital interactions with water for n > 6 leading to a planar square bipyramid hexacoordination around Cd. The first solvation shell is fully attained with 12 water molecules. At the same level of theory the water binding energies are much larger than those previously found for HgCl2 due to the stronger Cd-O(w) interactions arising from the smaller core of Cd. For the largest system studied, CdCl2-(H2O)24, both penta- and hexa-coordination stable patterns around Cd are found. However, Born-Opphenheimer molecular dynamics simulations starting from these optimized geometries at 700 K reveal the greater stability of the Cd-pentacoordinated species, where a CdCl2-(H2O)3 trigonal bipyramid effective solute appears. The Cd-O(water) radial distribution function shows a bimodal distribution with two maxima at 2.4 Å and 4.2 Å, revealing the different coordination spheres, even with such a small number of solvating water molecules.
Collapse
Affiliation(s)
- A Ramírez-Solís
- Laboratoire de Physicochimie de Nano-Objets, INSA-IRSAMC, Université de Toulouse III, 135, Avenue de Rangueil, Toulouse, F31077, France
| | - L Maron
- Laboratoire de Physicochimie de Nano-Objets, INSA-IRSAMC, Université de Toulouse III, 135, Avenue de Rangueil, Toulouse, F31077, France
| |
Collapse
|