1
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Dick L, Kirchner B. CONAN─Novel Tool to Create and Analyze Liquids in Confined Space. J Chem Inf Model 2023; 63:6706-6716. [PMID: 37907068 PMCID: PMC10649805 DOI: 10.1021/acs.jcim.3c01075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 11/02/2023]
Abstract
Modeling of complex liquids at solid surfaces and in confinement is gaining attention due to an increase in computer power and advancement of simulation techniques. Therefore, tools to set up structures and for analysis are needed. In this paper, we present CONAN─a Python code designed to facilitate the study of liquids interacting with solid structures, such as walls or pores. Among other things, the program provides the option to generate a variety of different structures, including carbon walls and nanotubes and their boron nitride analogs, as well as the ability to analyze various structural properties of confined and interfacial liquids. In the case of the ionic liquid 1-butyl-3-methylimidazolium acetate in carbon nanotubes of different sizes, we demonstrate the abilities of our tool. The average density within the confinement highly depends on the carbon nanotube size, and it is generally lower than the density of the bulk liquid. The arrangement of the individual species within the tube also depends on size, with radial layers forming within the tubular confinement. The density is largely increased in the respective layers, while it is drastically reduced between the layers.
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Affiliation(s)
- Leonard Dick
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
| | - Barbara Kirchner
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
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2
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Mendonça BHS, de Moraes EE, Kirch A, Batista RJC, de Oliveira AB, Barbosa MC, Chacham H. Flow through Deformed Carbon Nanotubes Predicted by Rigid and Flexible Water Models. J Phys Chem B 2023; 127:8634-8643. [PMID: 37754781 DOI: 10.1021/acs.jpcb.3c02889] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
In this study, using nonequilibrium molecular dynamics simulation, the flow of water in deformed carbon nanotubes is studied for two water models TIP4P/2005 and simple point charge/FH (SPC/FH). The results demonstrated a nonuniform dependence of the flow on the tube deformation and the flexibility imposed on the water molecules, leading to an unexpected increase in the flow in some cases. The effects of the tube diameter and pressure gradient are investigated to explain the abnormal flow behavior with different degrees of structural deformation.
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Affiliation(s)
- Bruno H S Mendonça
- Departamento de Física, ICEX, Universidade Federal de Minas Gerais, CP 702, Belo Horizonte 30123-970, MG, Brazil
| | - Elizane E de Moraes
- Instituto de Física, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador 40210-340, BA, Brazil
| | - Alexsandro Kirch
- Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo 05315-970, SP, Brazil
| | - Ronaldo J C Batista
- Departamento de Física, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto 35400-000, MG, Brazil
| | - Alan B de Oliveira
- Departamento de Física, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto 35400-000, MG, Brazil
| | - Marcia C Barbosa
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970, RS, Brazil
| | - Hélio Chacham
- Departamento de Física, ICEX, Universidade Federal de Minas Gerais, CP 702, Belo Horizonte 30123-970, MG, Brazil
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3
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R Leivas F, Barbosa MC. Functionalized carbon nanocones performance in water harvesting. J Chem Phys 2023; 158:2890471. [PMID: 37184010 DOI: 10.1063/5.0142718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/30/2023] [Indexed: 05/16/2023] Open
Abstract
In this work, we investigate the water capture process for functionalized carbon nanocones (CNCs) through molecular dynamic simulations in the following three scenarios: a single CNC in contact with a reservoir containing liquid water, a single CNC in contact with a water vapor reservoir, and a combination of more than one CNC in contact with vapor. We found that water flows through the nanocones when in contact with the liquid reservoir if the nanocone tip presents hydrophilic functionalization. In contact with steam, we observed the formation of droplets at the base of the nanocone only when hydrophilic functionalization is present. Then, water flows through in a linear manner, a process that is more efficient than that in the liquid reservoir regime. The scalability of the process is tested by analyzing the water flow through more than one nanocone. The results suggest that the distance between the nanocones is a fundamental ingredient for the efficiency of water harvesting.
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Affiliation(s)
- Fernanda R Leivas
- Instituto de Física, Universidade Federal do Rio Grande do Sul, CP 15051, 91501-970 Porto Alegre, RS, Brazil
| | - Marcia C Barbosa
- Instituto de Física, Universidade Federal do Rio Grande do Sul, CP 15051, 91501-970 Porto Alegre, RS, Brazil
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4
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Bang KR, Kwon C, Lee H, Kim S, Cho ES. Horizontally Asymmetric Nanochannels of Graphene Oxide Membranes for Efficient Osmotic Energy Harvesting. ACS NANO 2023. [PMID: 37196224 DOI: 10.1021/acsnano.2c11975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Reverse electrodialysis (RED) directly harvests renewable energy from salinity gradients, and the achievable potential power heavily relies on the ion exchange membranes. Graphene oxides (GOs) are considered a solid candidate for the RED membrane because the laminated GO nanochannels with charged functional groups provide an excellent ionic selectivity and conductivity. Yet, a high internal resistance and poor stability in aqueous solutions limit the RED performance. Here, we develop a RED membrane that concurrently achieves high ion permeability and stable operation based on epoxy-confined GO nanochannels with asymmetric structures. The membrane is fabricated by reacting epoxy-wrapped GO membranes with ethylene diamine via vapor diffusion, overcoming the swelling properties in aqueous solutions. More importantly, the resultant membrane exhibits asymmetric GO nanochannels in terms of both channel geometry and electrostatic surface charges, leading to the rectified ion transport behavior. The demonstrated GO membrane exhibits the RED performance up to 5.32 W·m-2 with >40% energy conversion efficiency across a 50-fold salinity gradient and 20.3 W·m-2 across a 500-fold salinity gradient. Planck-Nernst continuum models coupled to molecular dynamics simulations rationalize the improved RED performance in terms of the asymmetric ionic concentration gradient within the GO nanochannel and the ionic resistance. The multiscale model also provides the design guidelines for ionic diode-type membranes configuring the optimum surface charge density and ionic diffusivity for efficient osmotic energy harvesting. The synthesized asymmetric nanochannels and their RED performance demonstrate the nanoscale tailoring of the membrane properties, establishing the potentials for 2D material-based asymmetric membranes.
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Affiliation(s)
- Ki Ryuk Bang
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Choah Kwon
- Department of Nuclear Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Ho Lee
- Department of Nuclear Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Sangtae Kim
- Department of Nuclear Engineering, Hanyang University, Seoul 04763, Republic of Korea
- Department of Materials Science and Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Eun Seon Cho
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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5
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Leivas FR, Barbosa MC. Atmospheric water harvesting using functionalized carbon nanocones. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2023; 14:1-10. [PMID: 36703909 PMCID: PMC9830493 DOI: 10.3762/bjnano.14.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 12/14/2022] [Indexed: 05/28/2023]
Abstract
In this work, we propose a method to harvest liquid water from water vapor using carbon nanocones. The condensation occurs due to the presence of hydrophilic sites at the nanocone entrance. The functionalization, together with the high mobility of water inside nanostructures, leads to a fast water flow through the nanostructure. We show using molecular dynamics simulations that this device is able to collect water if the surface functionalization is properly selected.
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Affiliation(s)
- Fernanda R Leivas
- Instituto de Física, Universidade Federal do Rio Grande do Sul, CP 15051, 91501-970, Porto Alegre, RS, Brazil
| | - Marcia C Barbosa
- Instituto de Física, Universidade Federal do Rio Grande do Sul, CP 15051, 91501-970, Porto Alegre, RS, Brazil
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Arya V, Chaudhuri A, Bakli C. Coupling solute interactions with functionalized graphene membranes: towards facile membrane-level engineering. NANOSCALE 2022; 14:16661-16672. [PMID: 36330851 DOI: 10.1039/d2nr05552j] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Optimizing ion transport through nanoporous graphene membranes with intricate engineering at nanoscale levels finds applications ranging from ion segregation to desalination. Such membrane-level engineering often requires futuristic and state-of-the-art micro- and nanofabrication infrastructure making it less accessible to widespread applications. In this study, the effective membrane pore size is modulated using macroscopic membrane functionalization, which, when combined with the solute concentration, can prove to be facile nanoscale engineering towards achieving selectivity. By performing robust molecular dynamics (MD) simulations of aqueous NaCl solution through a nanoporous graphene membrane, we demonstrate that varying membrane wettability influences the structural organization of ions and water molecules both in the vicinity and inside the nanopore, which is manifested in the form of altered permeation characteristics. Moreover, the disparate solvation characteristics of the ionic species in conjunction with the variable van der Waals interactive forces affect the ion-selective nature (Cl- over Na+) of the membrane. The relative hydrophilization, resulting from the effective functionalization of the nanoporous graphene membrane, not only allows greater control over the permeation characteristics of ions and water molecules mediated by an altered depletion ratio but also gives rise to the ion-selective nature of the membrane, thus providing a sound understanding of the transport properties of ion-water solutions through nanoporous materials.
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Affiliation(s)
- Vinay Arya
- School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, India.
| | - Abhirup Chaudhuri
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, India
| | - Chirodeep Bakli
- School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, India.
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7
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Liu D, Li J, Wu J, Lu D. Ab Initio Molecular Dynamics Simulation of Water Transport through Short Carbon Nanotubes. ACS OMEGA 2022; 7:40466-40479. [PMID: 36385899 PMCID: PMC9647839 DOI: 10.1021/acsomega.2c05588] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Water transport through short single-walled (6, 6) carbon nanotubes (CNTs) was investigated with ab initio molecular dynamics (AIMD) simulation at different temperatures. The water molecules under extreme confinement present a one-dimensional jagged pattern owing to hydrogen bonding, with the near-perfect alignment of the dipole orientations. CNTs ending with dangling bonds can promote water dissociation near the entrance and the occurrence of dipole flipping along the water wire at high temperatures, accompanied by the formation of D defects and L defects in the hydrogen-bond network. In contrast, dissociation of water molecules rarely takes place if the dangling bonds at the ends of the CNTs are terminated with H atoms. Angular jumps of water molecules are commonplace inside the narrow CNTs, implying a low-energy barrier for hydrogen-bond exchange among water molecules in narrow CNTs. The simulation results demonstrate the high activity of dangling bonds at the ends of short CNTs, accompanying passivation processes and their profound impact on water structure and transport, which is important for diverse technological applications.
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Affiliation(s)
- Dongfei Liu
- Department
of Chemical Engineering, Tsinghua University, Beijing100084, P. R. China
| | - Jipeng Li
- School
of Materials Science and Engineering, Hainan
University, Haikou570228, P. R. China
| | - Jianzhong Wu
- Department
of Chemical and Environmental Engineering, University of California, Riverside, California92521, United States
| | - Diannan Lu
- Department
of Chemical Engineering, Tsinghua University, Beijing100084, P. R. China
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8
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Yamaoka S, Chang IY, Hyeon-Deuk K. Flow-Induced Autonomic Ordering of Hydrogen Molecules under a Non-Equilibrium Flow. J Phys Chem Lett 2022; 13:3579-3585. [PMID: 35426681 DOI: 10.1021/acs.jpclett.2c00914] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A non-equilibrium molecular flow through a carbon nanotube (CNT) serves as a key system for revealing molecular transport and establishing nanofluidics. It has been challenging to simulate a non-equilibrium flow of hydrogen molecules exhibiting strong nuclear quantumness. Taking advantage of the quantum molecular dynamics method that can calculate real-time trajectories of hydrogen molecules even under a non-equilibrium flow, we found that the non-equilibrium flow makes hydrogen molecules more condensed and accelerates their adsorption near a CNT surface, letting the molecules flow more smoothly by propagating velocity momenta more efficiently along the CNT axis and by suppressing transverse molecular dynamics on the CNT cross section. Such flow-induced autonomic ordering indicates the importance of monitoring and investigating dynamics and adsorption of hydrogen molecules under a non-equilibrium circumstance as well as in a quiet equilibrium state, opening a new strategy for efficient hydrogen liquefaction and storage.
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Affiliation(s)
- Shutaro Yamaoka
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan
| | - I-Ya Chang
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan
| | - Kim Hyeon-Deuk
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan
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9
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Mejri A, Mazouzi K, Herlem G, Picaud F, Hennequin T, Palmeri J, Manghi M. Molecular dynamics investigations of ionic conductance at the nanoscale: Role of the water model and geometric parameters. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Robinson F, Park C, Kim M, Kim D. Defect induced deformation effect on water transport through (6, 6) carbon nanotube. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Jia Y, Lu X, Cao Z, Yan T. From a bulk to nanoconfined water chain: bridge water at the pore of the (6,6) carbon nanotube. Phys Chem Chem Phys 2020; 22:25747-25759. [PMID: 33146653 DOI: 10.1039/d0cp02531c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrophobic porous materials with nano-pores are critical in many processes such as water desalination and biological membrane transportation. Herein, we performed molecular dynamics (MD) simulations on a prototypical hydrophobic nanochannel consisting of a (6,6) carbon nanotube (CNT) of 4.12 Å in radius and 13.72 Å in length immersed in water. The simulation shows that there are two major filling numbers of water N = 5 and N = 6, with the former being the most stable one. The confined waters form a single-file water chain with two hydrogen bonds per water. An extending water chain is formed for N = 5, with a bridge water near the pore of the CNT linking the water confined inside the CNT and hydration layer around the pore of the CNT. The bridge water can be considered as intermediate water characterized by three hydrogen bonds that distinguish from the confined water and bulk water. On the other hand, the hydration layer is depleted from the pore when N = 6. The analyses of the correlation of the bond order for the adjacent hydrogen bond pair of the hydration layer around the pore of the CNT does not show apparent difference from that of bulk water, though the former is slightly ordered. van Hove analysis of the bridge water shows that it tends to move inside the CNT when N < 5, in order to maintain the chemical equilibrium between the confined water and bulk water. This study highlights the unique structure of water around the hydrophobic pore of a sub-nanometer nanochannel.
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Affiliation(s)
- Yunzhe Jia
- Institute of New Energy Material Chemistry, School of Materials Science and Engineering, Nankai University, Tianjin 300350, China.
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12
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Ebrahimi F, Maktabdaran GR, Sahimi M. Formation of a Stable Bridge between Two Disjoint Nanotubes with Single-File Chains of Water. J Phys Chem B 2020; 124:8340-8346. [PMID: 32894671 DOI: 10.1021/acs.jpcb.0c05331] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It was recently demonstrated that stable water bridges can form between two relatively large disjoint nanochannels, such as carbon nanotubes (CNTs), under an applied pressure drop. Such bridges are relevant to fabrication of nanostructured materials, drug delivery, water desalination devices, hydrogen fuel cells, dip-pen nanolithography, and several other applications. If the nanotubes are small enough, however, then one has only single-file hydrogen-bonded chains of water molecules. The distribution of water in such nanotubes manifests unusual physical properties that are attributed to the low number of hydrogen bonds (HBs) formed in the channel since, on average, each water molecule in a single-file chain forms only 1.7 HBs, almost half of the value for bulk water. Using extensive molecular dynamics simulations, we demonstrate that stable bridges can form even between two small disjoint CNTs that contain single-file chains of water. The structure, stability, and properties of such bridges and their dependence on the applied pressure drop and the length of the gap between the two CNTs are studied in detail, as is the distribution of the HBs. We demonstrate, in particular, that the efficiency of flow through the bridge is at maximum at a specific pressure difference.
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Affiliation(s)
- Fatemeh Ebrahimi
- Department of Physics, University of Birjand, Birjand 97175-615, Iran
| | - G R Maktabdaran
- Department of Physics, University of Birjand, Birjand 97175-615, Iran
| | - Muhammad Sahimi
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211, United States
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13
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Sam A, Hartkamp R, Kumar Kannam S, Babu JS, Sathian SP, Daivis PJ, Todd BD. Fast transport of water in carbon nanotubes: a review of current accomplishments and challenges. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1782401] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Alan Sam
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
| | - Remco Hartkamp
- Process and Energy Department, Delft University of Technology, Delft, The Netherlands
| | - Sridhar Kumar Kannam
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Australia
| | - Jeetu S. Babu
- Department of Mechanical Engineering, Amrita Vishwa Vidyapeetham, Amritapuri, India
| | - Sarith P. Sathian
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
| | - Peter J. Daivis
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - B. D. Todd
- Department of Mathematics, Swinburne University of Technology, Melbourne, Australia
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Velioğlu S, Karahan HE, Goh K, Bae TH, Chen Y, Chew JW. Metallicity-Dependent Ultrafast Water Transport in Carbon Nanotubes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1907575. [PMID: 32432833 DOI: 10.1002/smll.201907575] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 04/11/2020] [Accepted: 04/18/2020] [Indexed: 06/11/2023]
Abstract
Carbon nanotubes (CNTs) with hydrophobic and atomically smooth inner channels are promising for building ultrahigh-flux nanofluidic platforms for energy harvesting, health monitoring, and water purification. Conventional wisdom is that nanoconfinement effects determine water transport in CNTs. Here, using full-atomistic molecular dynamics simulations, it is shown that water transport behavior in CNTs strongly correlates with the electronic properties of single-walled CNTs (metallic (met) vs semiconducting (s/c)), which is as dominant as the effect of nanoconfinement. Three pairs of CNTs (i.e., (8,8)met , 10.85 Å vs (9,7)s/c , 10.88 Å; (9,8)s/c , 11.53 Å vs (10,7)met , 11.59 Å; and (9,9)met , 12.20 Å vs (10,8)s/c , 12.23 Å) are used to investigate the roles of diameter and metallicity. Specifically, the (9,8)s/c can restrict the hydrogen-bonding-mediated structuring of water and give the highest reduction in carbon-water interaction energy, providing an extraordinarily high water flux, around 250 times that of the commercial reverse osmosis membranes and approximately fourfold higher than the flux of the state-of-the-art boron nitrate nanotubes. Further, the high performance of (9,8)s/c is also reproducible when embedded in lipid bilayers as synthetic high-water flux porins. Given the increasing availability of high-purity CNTs, these findings provide valuable guides for realizing novel CNT-enhanced nanofluidic systems.
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Affiliation(s)
- Sadiye Velioğlu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
- Institute of Nanotechnology, Gebze Technical University, Kocaeli, 41400, Turkey
| | - Hüseyin Enis Karahan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
- Singapore Membrane Technology Center (SMTC), Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141, Singapore
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Kunli Goh
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
- Singapore Membrane Technology Center (SMTC), Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141, Singapore
| | - Tae-Hyun Bae
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
- Singapore Membrane Technology Center (SMTC), Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141, Singapore
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Yuan Chen
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Jia Wei Chew
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
- Singapore Membrane Technology Center (SMTC), Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, 637141, Singapore
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15
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Abal JPK, Bordin JR, Barbosa MC. Salt parameterization can drastically affect the results from classical atomistic simulations of water desalination by MoS 2 nanopores. Phys Chem Chem Phys 2020; 22:11053-11061. [PMID: 32373906 DOI: 10.1039/d0cp00484g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Water scarcity is a reality in our world, and scenarios predicted by leading scientists in this area indicate that it will worsen in the next decades. However, new technologies based on low-cost seawater desalination can prevent the worst scenarios, providing fresh water for humanity. With this goal, membranes based on nanoporous materials have been suggested in recent years. One of the materials suggested is MoS2, and classical Molecular Dynamics (MD) simulation is one of the most powerful tools to explore these nanomaterials. However, distinct force fields employed in MD simulations are parameterized based on distinct experimental quantities. In this paper, we compare two models of salt that were built based on distinct properties of water-salt mixtures. One model fits the hydration free energy and lattice properties, and the second fits the crystal density and the density and the dielectric constant of water and salt mixtures. To compare the models, MD simulations for salty water flow through nanopores of two sizes were used - one pore big enough to accommodate hydrated ions, and one smaller in which the ion has to dehydrate to enter - and two rigid water models from the TIP4P family - TIP4P/2005 and TIP4P/ε. Our results indicate that the water permeability and salt rejection by the membrane are more influenced by the salt model than by the water model, especially for the narrow pore. In fact, completely distinct mechanisms were observed, and they are related to the characteristics employed in the ion model parameterization. The results show that not only can the water model influence the outcomes, but the ion model plays a crucial role when the pore is small enough.
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Affiliation(s)
- João P K Abal
- Institute of Physics, Federal University of Rio Grande do Sul, 91501-970, Porto Alegre, Brazil.
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