1
|
Hunvik KWB, Seljelid KK, Wallacher D, Kirch A, Cavalcanti LP, Loch P, Røren PM, Michels-Brito PH, Droppa-Jr R, Knudsen KD, Miranda CR, Breu J, Fossum JO. Intercalation of CO 2 Selected by Type of Interlayer Cation in Dried Synthetic Hectorite. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4895-4903. [PMID: 36989083 PMCID: PMC10100549 DOI: 10.1021/acs.langmuir.2c03093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 03/14/2023] [Indexed: 06/19/2023]
Abstract
Clay minerals are abundant in caprock formations for anthropogenic storage sites for CO2, and they are potential capture materials for CO2 postcombustion sequestration. We investigate the response to CO2 exposure of dried fluorohectorite clay intercalated with Li+, Na+, Cs+, Ca2+, and Ba2+. By in situ powder X-ray diffraction, we demonstrate that fluorohectorite with Na+, Cs+, Ca2+, or Ba2+ does not swell in response to CO2 and that Li-fluorohectorite does swell. A linear uptake response is observed for Li-fluorohectorite by gravimetric adsorption, and we relate the adsorption to tightly bound residual water, which exposes adsorption sites within the interlayer. The experimental results are supported by DFT calculations.
Collapse
Affiliation(s)
- Kristoffer W. Bø Hunvik
- Department
of Physics, Norwegian University of Science
and Technology, N-7491 Trondheim, Norway
| | | | | | - Alexsandro Kirch
- Departamento
de Física dos Materiais e Mecânica, Instituto de Física, Universidade de São Paulo, 05508-090 São
Paulo, SP Brazil
| | | | - Patrick Loch
- Bavarian
Polymer Institute and Department of Chemistry, University of Bayreuth, 95447 Bayreuth, Germany
| | - Paul Monceyron Røren
- Department
of Physics, Norwegian University of Science
and Technology, N-7491 Trondheim, Norway
| | | | - Roosevelt Droppa-Jr
- Universidade
Federal do ABC (UFABC), Av. dos Estados, 5001 - Santa Terezinha, Santo
André, SP CEP 09210-580, Brazil
| | - Kenneth Dahl Knudsen
- Department
of Physics, Norwegian University of Science
and Technology, N-7491 Trondheim, Norway
- Institute
for Energy Technology (IFE), 2007 Kjeller, Norway
| | - Caetano Rodrigues Miranda
- Departamento
de Física dos Materiais e Mecânica, Instituto de Física, Universidade de São Paulo, 05508-090 São
Paulo, SP Brazil
| | - Josef Breu
- Bavarian
Polymer Institute and Department of Chemistry, University of Bayreuth, 95447 Bayreuth, Germany
| | - Jon Otto Fossum
- Department
of Physics, Norwegian University of Science
and Technology, N-7491 Trondheim, Norway
| |
Collapse
|
2
|
Cunniff SS, Schaef HT, Burton SD, Walter ED, Hoyt DW, Loring JS, Bowers GM. Interlayer Cation Polarizability Affects Supercritical Carbon Dioxide Adsorption by Swelling Clays. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15540-15551. [PMID: 36469510 DOI: 10.1021/acs.langmuir.2c02139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Several strategies for mitigating the build-up of atmospheric carbon dioxide (CO2) bring wet supercritical CO2 (scCO2) in contact with phyllosilicates such as illites and smectites. While some work has examined the role of the charge-balancing cation and smectite framework features on CO2/smectite interactions, to our knowledge no one has examined how the polarizability of the charge-balancing cation influences these behaviors. In this paper, the scCO2 adsorption properties of Pb2+, Rb+, and NH4+ saturated smectite clays at variable relative humidity are studied by integrating in situ high-pressure X-ray diffraction (XRD), infrared spectroscopic titrations, and magic angle spinning nuclear magnetic resonance (MAS NMR) methods. The results are combined with previously published data for Na+, Cs+, and Ca2+ saturated versions of the same smectites to isolate the roles of the charge-balancing cations and perform two independent tests of the role of charge-balancing cation polarizability in determining the interlayer fluid properties and smectite expansion. Independent correlations developed for (i) San Bernardino hectorite (SHCa-1) and (ii) Wyoming montmorillonite (SWy-2) both show that cation polarizability is important in predicting the interlayer composition (mol% CO2 in the interlayer fluid and CO2/cation ratio in interlayer) and the expansion behavior for smectites in contact with wet and dry scCO2. In particular, this study shows that the charge-balancing cation polarizability is the most important cation-associated parameter in determining the expansion of the trioctahedral smectite, hectorite, when in contact with dry scCO2. While both independent tests show that cation polarizability is an important factor in smectite-scCO2 systems, the correlations for hectorite are different from those determined for montmorillonite. The root of these differences is likely associated with the roles of the smectite framework on adsorption, warranting follow-up studies with a larger number of unique smectite frameworks. Overall, the results show that the polarizability of the charge-balancing cation should be considered when preparing smectite clays (or industrial processes involving smectites) to capture CO2 and in predicting the behavior of caprocks over time.
Collapse
Affiliation(s)
- Sydney S Cunniff
- Department of Chemistry and Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland20686, United States
| | - H Todd Schaef
- Pacific Northwest National Laboratory, Richland, Washington99352, United States
| | - Sarah D Burton
- William R. Wiley Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington99352, United States
| | - Eric D Walter
- William R. Wiley Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington99352, United States
| | - David W Hoyt
- William R. Wiley Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington99352, United States
| | - John S Loring
- Pacific Northwest National Laboratory, Richland, Washington99352, United States
| | - Geoffrey M Bowers
- Department of Chemistry and Biochemistry, St. Mary's College of Maryland, St. Mary's City, Maryland20686, United States
| |
Collapse
|
3
|
Xi C, Zheng F, Gao G, Song Z, Zhang B, Dong C, Du XW, Wang LW. Ion Solvation Free Energy Calculation Based on Ab Initio Molecular Dynamics Using a Hybrid Solvent Model. J Chem Theory Comput 2022; 18:6878-6891. [PMID: 36253911 DOI: 10.1021/acs.jctc.1c01298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Free energy calculation of small molecules or ion species in aqueous solvent is one of the most important problems in electrochemistry study. Although there are many previous approaches to calculate such free energies, they are based on ab initio methods and suffer from various limitations and approximations. In the current work, we developed a hybrid approach based on ab initio molecular dynamics (AIMD) simulations to calculate the ion solvation energy. In this approach, a small water cluster surrounding the central ion is used, and implicit solvent model is applied outside the water cluster. A dynamic potential well is used during AIMD to keep the water cluster together. Quasi-harmonic approximation is used to calculate the entropy contribution, while the total energy average is used to calculate the enthalpy term. The obtained solvation voltages of the bulk metal agree with experiments within 0.3 eV, and the simulation results for the solvation energies of gaseous ions are close to the experimental observations. Besides the free energies, radial pair distribution functions and coordination numbers of hydrated cations are also obtained. The remaining challenges of this method are also discussed.
Collapse
Affiliation(s)
- Cong Xi
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States.,Institute of New Energy Materials, School of Materials Science and Engineering, Tianjin University, Tianjin30072, People's Republic of China
| | - Fan Zheng
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Guoping Gao
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Zhigang Song
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Buyu Zhang
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Cunku Dong
- Institute of New Energy Materials, School of Materials Science and Engineering, Tianjin University, Tianjin30072, People's Republic of China
| | - Xi-Wen Du
- Institute of New Energy Materials, School of Materials Science and Engineering, Tianjin University, Tianjin30072, People's Republic of China
| | - Lin-Wang Wang
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| |
Collapse
|
4
|
Loring JS, Qafoku O, Thompson CJ, McNeill AS, Vasiliu M, Dixon DA, Miller QRS, McGrail BP, Rosso KM, Ilton ES, Schaef HT. Synergistic Coupling of CO 2 and H 2O during Expansion of Clays in Supercritical CO 2-CH 4 Fluid Mixtures. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:11192-11203. [PMID: 34342971 DOI: 10.1021/acs.est.1c00275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We used IR and XRD, with supporting theoretical calculations, to investigate the swelling behavior of Na+-, NH4+-, and Cs+-montmorillonites (SWy-2) in supercritical fluid mixtures of H2O, CO2, and CH4. Building on our prior work with Na-clay that demonstrated that H2O facilitated CO2 intercalation at relatively low RH, here we show that increasing CO2/CH4 ratios promote H2O intercalation and swelling of the Na-clay at progressively lower RH. In contrast to the Na-clay, CO2 intercalated and expanded the Cs-clay even in the absence of H2O, while increasing fluid CO2/CH4 ratios inhibited H2O intercalation. The NH4-clay displayed intermediate behavior. By comparing changes in the HOH bending vibration of H2O intercalated in the Cs-, NH4-, and Na-clays, we posit that CO2 facilitated expansion of the Na-clay by participating in outer-sphere solvation of Na+ and by disrupting the H-bond network of intercalated H2O. In no case did the pure CH4 fluid induce expansion. Our experimental data can benchmark modeling studies aimed at predicting clay expansion in humidified fluids with varying ratios of CO2 and CH4 in real reservoir systems with implications for enhanced hydrocarbon recovery and CO2 storage in subsurface environments.
Collapse
Affiliation(s)
- John S Loring
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Odeta Qafoku
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | | | - Ashley S McNeill
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Monica Vasiliu
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - David A Dixon
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Quin R S Miller
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - B Peter McGrail
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Kevin M Rosso
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Eugene S Ilton
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Herbert T Schaef
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| |
Collapse
|
5
|
Dissolution behaviors of alkyl block polyethers in CO2: Experimental measurements and molecular dynamics simulations. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2020.115953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
6
|
Rimsza JM, Kuhlman KL. Surface Energies and Structure of Salt-Brine Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2482-2491. [PMID: 32097016 DOI: 10.1021/acs.langmuir.9b03172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Permeability of salt formations is controlled by the equilibrium between the salt-brine and salt-salt interfaces described by the dihedral angle, which can change with the composition of the intergranular brine. Here, classical molecular dynamics (MD) simulations were used to investigate the structure and properties of the salt-brine interface to provide insight into the stability of salt systems. Mixed NaCl-KCl brines were investigated to explore differences in ion size on the surface energy and interface structure. Nonlinearity was noted in the salt-brine surface energy with increasing KCl concentration, and the addition of 10% KCl increased surface energies by 2-3 times (5.0 M systems). Size differences in Na+ and K+ ions altered the packing of dissolved ions and water molecules at the interface, impacting the surface energy. Additionally, ions at the interface had lower numbers of coordinating water molecules than those in the bulk and increased hydration for ions in systems with 100% NaCl or 100% KCl brines. Ultimately, small changes in brine composition away from pure NaCl altered the structure of the salt-brine interface, impacting the dihedral angle and the predicted equilibrium permeability of salt formations.
Collapse
Affiliation(s)
- Jessica M Rimsza
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87123, United States
| | - Kristopher L Kuhlman
- Applied Systems Analysis & Research, Sandia National Laboratories, Albuquerque, New Mexico 87123, United States
| |
Collapse
|
7
|
Cavalcanti LP, Kalantzopoulos GN, Eckert J, Knudsen KD, Fossum JO. A nano-silicate material with exceptional capacity for CO 2 capture and storage at room temperature. Sci Rep 2018; 8:11827. [PMID: 30087394 PMCID: PMC6081458 DOI: 10.1038/s41598-018-30283-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 07/26/2018] [Indexed: 11/09/2022] Open
Abstract
In order to mitigate climate change driven by the observed high levels of carbon dioxide (CO2) in the atmosphere, many micro and nano-porous materials are being investigated for CO2 selectivity, capture and storage (CCS) purposes, including zeolites, metal organic frameworks (MOFs), functionalized polymers, activated carbons and nano-silicate clay minerals. Key properties include availability, non-toxicity, low cost, stability, energy of adsorption/desorption, sorbent regeneration, sorption kinetics and CO2 storage capacity. Here, we address the crucial point of the volumetric capture and storage capacity for CO2 in a low cost material which is natural, non-toxic, and stable. We show that the nano-silicate Nickel Fluorohectorite is able to capture 0.79 metric tons of CO2 per m3 of host material - one of the highest capacities ever achieved - and we compare volumetric and gravimetric capacity of the best CO2 sorbent materials reported to date. Our results suggest that the high capture capacity of this fluorohectorite clay is strongly coupled to the type and valence of the interlayer cation (here Ni2+) and the high charge density, which is almost twice that of montmorillonite, resulting in the highest reported CO2 uptake among clay minerals.
Collapse
Affiliation(s)
| | - Georgios N Kalantzopoulos
- Centre for Materials Science and Nanotechnology (SMN), Department of Chemistry, University of Oslo, Oslo, Norway
| | | | - Kenneth D Knudsen
- Institute for Energy Technology (IFE), Kjeller, Norway.,Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Jon Otto Fossum
- Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
| |
Collapse
|
8
|
Keshri S, Tembe B. Ion association in binary mixtures of water-CO2 in supercritical conditions through classical molecular dynamics simulations. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.02.052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
9
|
Ho TA, Ilgen A. Density Fluctuation in Aqueous Solutions and Molecular Origin of Salting-Out Effect for CO 2. J Phys Chem B 2017; 121:11485-11491. [PMID: 29072910 DOI: 10.1021/acs.jpcb.7b09215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using molecular dynamics simulation, we studied the density fluctuations and cavity formation probabilities in aqueous solutions and their effect on the hydration of CO2. With increasing salt concentration, we report an increased probability of observing a larger than the average number of species in the probe volume. Our energetic analyses indicate that the van der Waals and electrostatic interactions between CO2 and aqueous solutions become more favorable with increasing salt concentration, favoring the solubility of CO2 (salting in). However, due to the decreasing number of cavities forming when salt concentration is increased, the solubility of CO2 decreases. The formation of cavities was found to be the primary control on the dissolution of gas, and is responsible for the observed CO2 salting-out effect. Our results provide the fundamental understanding of the density fluctuation in aqueous solutions and the molecular origin of the salting-out effect for real gas.
Collapse
Affiliation(s)
- Tuan Anh Ho
- Geochemistry Department, Sandia National Laboratories , Albuquerque, New Mexico 87185, United States
| | - Anastasia Ilgen
- Geochemistry Department, Sandia National Laboratories , Albuquerque, New Mexico 87185, United States
| |
Collapse
|
10
|
Schaef HT, Loganathan N, Bowers GM, Kirkpatrick RJ, Yazaydin AO, Burton SD, Hoyt DW, Thanthiriwatte KS, Dixon DA, McGrail BP, Rosso KM, Ilton ES, Loring JS. Tipping Point for Expansion of Layered Aluminosilicates in Weakly Polar Solvents: Supercritical CO 2. ACS APPLIED MATERIALS & INTERFACES 2017; 9:36783-36791. [PMID: 28952722 DOI: 10.1021/acsami.7b10590] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Layered aluminosilicates play a dominant role in the mechanical and gas storage properties of the subsurface, are used in diverse industrial applications, and serve as model materials for understanding solvent-ion-support systems. Although expansion in the presence of H2O is well-known to be systematically correlated with the hydration free energy of the interlayer cation, particularly in environments dominated by nonpolar solvents (i.e., CO2), uptake into the interlayer is not well-understood. Using novel high-pressure capabilities, we investigated the interaction of dry supercritical CO2 with Na-, NH4-, and Cs-saturated montmorillonite, comparing results with predictions from molecular dynamics simulations. Despite the known trend in H2O and that cation solvation energies in CO2 suggest a stronger interaction with Na, both the NH4- and Cs-clays readily absorbed CO2 and expanded, while the Na-clay did not. The apparent inertness of the Na-clay was not due to kinetics, as experiments seeking a stable expanded state showed that none exists. Molecular dynamics simulations revealed a large endothermicity to CO2 intercalation in the Na-clay but little or no energy barrier for the NH4- and Cs-clays. Indeed, the combination of experiment and theory clearly demonstrate that CO2 intercalation of Na-montmorillonite clays is prohibited in the absence of H2O. Consequently, we have shown for the first time that in the presence of a low dielectric constant, gas swelling depends more on the strength of the interaction between the interlayer cation and aluminosilicate sheets and less on that with solvent. The finding suggests a distinct regime in layered aluminosilicate swelling behavior triggered by low solvent polarizability, with important implications in geomechanics, storage, and retention of volatile gases, and across industrial uses in gelling, decoloring, heterogeneous catalysis, and semipermeable reactive barriers.
Collapse
Affiliation(s)
- Herbert T Schaef
- Pacific Northwest National Laboratory , Richland, Washington 99356, United States
| | - Narasimhan Loganathan
- College of Natural Science, Michigan State University , East Lansing, Michigan 48824, United States
| | - Geoffrey M Bowers
- Department of Chemistry and Biochemistry, St. Mary's College of Maryland , St. Mary's City, Maryland 20686, United States
| | - R James Kirkpatrick
- College of Natural Science, Michigan State University , East Lansing, Michigan 48824, United States
| | - A Ozgur Yazaydin
- College of Natural Science, Michigan State University , East Lansing, Michigan 48824, United States
- Department of Chemical Engineering, University College London , London WC1E 7JE, United Kingdom
| | - Sarah D Burton
- William R. Wiley Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99356, United States
| | - David W Hoyt
- William R. Wiley Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99356, United States
| | - K Sahan Thanthiriwatte
- Department of Chemistry, The University of Alabama , Tuscaloosa, Alabama 35487, United States
| | - David A Dixon
- Department of Chemistry, The University of Alabama , Tuscaloosa, Alabama 35487, United States
| | - B Peter McGrail
- Pacific Northwest National Laboratory , Richland, Washington 99356, United States
| | - Kevin M Rosso
- Pacific Northwest National Laboratory , Richland, Washington 99356, United States
| | - Eugene S Ilton
- Pacific Northwest National Laboratory , Richland, Washington 99356, United States
| | - John S Loring
- Pacific Northwest National Laboratory , Richland, Washington 99356, United States
| |
Collapse
|
11
|
Keshri S, Mandal R, Tembe B. Solvation structures and dynamics of alkaline earth metal halides in supercritical water: A molecular dynamics study. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2016.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
12
|
Lee MS, Peter McGrail B, Rousseau R, Glezakou VA. Structure, dynamics and stability of water/scCO2/mineral interfaces from ab initio molecular dynamics simulations. Sci Rep 2015; 5:14857. [PMID: 26456362 PMCID: PMC4600984 DOI: 10.1038/srep14857] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/28/2015] [Indexed: 11/29/2022] Open
Abstract
The boundary layer at solid-liquid interfaces is a unique reaction environment that poses significant scientific challenges to characterize and understand by experimentation alone. Using ab initio molecular dynamics (AIMD) methods, we report on the structure and dynamics of boundary layer formation, cation mobilization and carbonation under geologic carbon sequestration scenarios (T = 323 K and P = 90 bar) on a prototypical anorthite (001) surface. At low coverage, water film formation is enthalpically favored, but entropically hindered. Simulated adsorption isotherms show that a water monolayer will form even at the low water concentrations of water-saturated scCO2. Carbonation reactions readily occur at electron-rich terminal Oxygen sites adjacent to cation vacancies that readily form in the presence of a water monolayer. These results point to a carbonation mechanism that does not require prior carbonic acid formation in the bulk liquid. This work also highlights the modern capabilities of theoretical methods to address structure and reactivity at interfaces of high chemical complexity.
Collapse
Affiliation(s)
- Mal-Soon Lee
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - B. Peter McGrail
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Roger Rousseau
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | | |
Collapse
|
13
|
Yazaydin AO, Bowers GM, Kirkpatrick RJ. Molecular dynamics modeling of carbon dioxide, water and natural organic matter in Na-hectorite. Phys Chem Chem Phys 2015; 17:23356-67. [PMID: 26286865 DOI: 10.1039/c5cp03552j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular dynamics (MD) modeling of systems containing a Na-exchanged smectite clay (hectorite) and model natural organic matter (NOM) molecules along with pure H2O, pure CO2, or a mixture of H2O and CO2 provides significant new insight into the molecular scale interactions among silicate surfaces, dissolved cations and organic molecules, H2O and CO2 relevant to geological C-sequestration strategies. The simulations for systems containing H2O show the following results; (1) Na(+) does not bridge between NOM molecules and the clay surface at protonation states comparable to near neutral pH conditions. (2) In systems without CO2 the NOM molecules retain charge balancing cations and drift away from the silicate surface. (3) In systems containing both H2O and CO2, the NOM molecules adopt equilibrium positions at the H2O-CO2 interface with the more hydrophilic structural elements facing the H2O and the more hydrophobic ones facing the CO2. In systems with only CO2, NOM and Na(+) ions are pinned to the clay surface with the hydrophilic structural elements of the NOM pointed toward the clay surface. Dynamically, in systems with only CO2, Na(+) diffusion is nearly eliminated, and in systems with a thin water film on the clay surface diffusion perpendicular the surface is greatly reduced relative to the system with bulk water. Energetically, the results for the systems with only H2O show that hydration of the net charge neutral Na-NOM molecule outweighs the sum of its Coulombic and dispersive interactions with the net charge-neutral Na-clay particle and the interactions of the water molecules with the hydrophobic structural elements of the NOM. The aggregation of NOM molecules in solution appears to be driven not by Na(+) bridging between the molecules but by hydrophobic interactions between them. In contrast, for the systems with only CO2 the interaction between the Na-NOM molecules and the CO2 is outweighed by the interaction of NOM with the clay particle. With both H2O and CO2 present, the energetic interactions leading to the hydration of the Na-clay surface and the hydrophilic structural elements of the Na-NOM molecule and the hydrophobic interactions between the CO2 and the hydrophobic aromatic and aliphatic structural elements of the NOM can both be satisfied, leading to the Na-NOM molecules migrating away from the surface and residing at the H2O-CO2 interface. The MD results suggest some alternative explanations for the previously observed (23)Na NMR behavior of Na-hectorite at elevated temperatures and CO2 pressures.
Collapse
Affiliation(s)
- A Ozgur Yazaydin
- Department of Chemical Engineering, University College London, London, WC1E7JE, UK.
| | | | | |
Collapse
|
14
|
Capobianco RM, Gruszkiewicz MS, Bodnar RJ, Donald Rimstidt J. Conductivity Measurements on H2O-Bearing CO2-Rich Fluids. J SOLUTION CHEM 2014. [DOI: 10.1007/s10953-014-0219-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|