1
|
Reddy PR, Anki Reddy K, Kumar A. Comparative Retention Analysis of Intercalated Cations Inside the Interlayer Gallery of Lamellar and Nonlamellar Graphene Oxide Membranes in Reverse Osmosis Process: A Molecular Dynamics Study. J Phys Chem B 2024; 128:5218-5227. [PMID: 38756068 DOI: 10.1021/acs.jpcb.4c01623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Over the past decade, multilayered graphene oxide (GO) membranes have emerged as promising candidates for desalination applications. Despite their potential, a comprehensive understanding of separation mechanisms remains elusive due to the intricate morphology and structural arrangement of interlayer galleries. Moreover, a critical concern of multilayered GO membranes is their susceptibility to swelling within aqueous environments, which hinders their practical implementation. Therefore, this study introduces cation intercalation within GO laminates to elucidate the underlying factors governing swelling behavior and subsequently mitigate it. Moreover, this study performed nonequilibrium molecular dynamics simulations on the cation (Mg2+ or K+)-intercalated lamellar and nonlamellar GO membranes to understand the effect of the arrangement of GO sheets on the retention time of intercalated cations within GO layers, water permeance, and salt rejection mechanism in the reverse osmosis process using cation-intercalated GO membranes. Our results highlight that lamellar GO membranes exhibit higher water permeance, attributed to their well-defined interlayer gallery structure. On the other hand, nonlamellar GO membranes display superior salt rejection due to their complex interlayer gallery structure that impedes salt permeation. Moreover, the structural complexity of nonlamellar GO membranes contributes to greater stability by retention of the more intercalated cations for a longer time within the layers. Furthermore, it is observed that a higher percentage of Mg2+ cations remained inside the GO laminates as compared to K+ cations, hence resulting in the greater stability of the Mg2+-intercalated GO membrane in the aqueous environment.
Collapse
Affiliation(s)
- P Rajasekhar Reddy
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039 Assam, India
| | - K Anki Reddy
- Department of Chemical Engineering, Indian Institute of Technology Tirupati, Tirupati, 517619 Andhra Pradesh, India
| | - Amit Kumar
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039 Assam, India
| |
Collapse
|
2
|
Shaharudin MR, Williams CD, Achari A, Nair RR, Carbone P. Decoding the Interplay between Topology and Surface Charge in Graphene Oxide Membranes During Humidity Induced Swelling. ACS NANO 2023; 17:21923-21934. [PMID: 37917940 PMCID: PMC10655246 DOI: 10.1021/acsnano.3c08260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/04/2023]
Abstract
Graphene oxide (GO) membranes are known to have a complex morphology that depends on the degree of oxidation of the graphene flake and the membrane preparation technique. In this study, using Grand Canonical Monte Carlo simulations, we investigate the mechanism of swelling of GO membranes exposed to different relative humidity (RH) values and show how this is intimately related to the graphene surface chemistry. We show that the structure of the GO membrane changes while the membrane adsorbs water from the environment and that graphene oxide flakes become charged as the membrane is loaded with water and swells. A detailed comparison between simulation and experimental adsorption data reveals that the flake surface charge drives the water adsorption mechanism at low RH when the membrane topology is still disordered and the internal pores are small and asymmetric. As the membrane is exposed to higher RH (80%), the flake acquires more surface charge as more oxide groups deprotonate, and the pores grow in size, yet maintain their disordered geometry. Only for very high relative humidity (98%) does the membrane undergo structural changes. At this level of humidity, the pores in the membrane become slit-like but the flake surface charge remains constant. Our results unveil a very complex mechanism of swelling and show that a single molecular model cannot fully capture the ever-changing chemistry and morphology of the membrane as it swells. Our computational procedure provides the first atomically resolved insight into the GO membrane structure of experimental samples.
Collapse
Affiliation(s)
- Mohd Rafie
bin Shaharudin
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Booth Street East, M13 9PL Manchester, United Kingdom
| | - Christopher D. Williams
- Division
of Pharmacy and Optometry, School of Health Sciences, The University of Manchester, Oxford Road, M13 9PT Manchester, United Kingdom
| | - Amritroop Achari
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Booth Street East, M13 9PL Manchester, United Kingdom
- National
Graphene Institute, The University of Manchester, Booth Street East, M13 9PL Manchester, United Kingdom
| | - Rahul R. Nair
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Booth Street East, M13 9PL Manchester, United Kingdom
- National
Graphene Institute, The University of Manchester, Booth Street East, M13 9PL Manchester, United Kingdom
| | - Paola Carbone
- Department
of Chemical Engineering, School of Engineering, The University of Manchester, Booth Street East, M13 9PL Manchester, United Kingdom
| |
Collapse
|
3
|
The role of surface ionisation in the hydration-induced swelling of graphene oxide membranes. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
4
|
Chen Y, Yang X. Molecular simulation of layered GO membranes with amorphous structure for heavy metal ions separation. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120863] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
5
|
Chen SH, Bell DR, Luan B. Understanding interactions between biomolecules and two-dimensional nanomaterials using in silico microscopes. Adv Drug Deliv Rev 2022; 186:114336. [PMID: 35597306 PMCID: PMC9212071 DOI: 10.1016/j.addr.2022.114336] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/08/2022] [Accepted: 05/06/2022] [Indexed: 12/28/2022]
Abstract
Two-dimensional (2D) nanomaterials such as graphene are increasingly used in research and industry for various biomedical applications. Extensive experimental and theoretical studies have revealed that 2D nanomaterials are promising drug delivery vehicles, yet certain materials exhibit toxicity under biological conditions. So far, it is known that 2D nanomaterials possess strong adsorption propensities for biomolecules. To mitigate potential toxicity and retain favorable physical and chemical properties of 2D nanomaterials, it is necessary to explore the underlying mechanisms of interactions between biomolecules and nanomaterials for the subsequent design of biocompatible 2D nanomaterials for nanomedicine. The purpose of this review is to integrate experimental findings with theoretical observations and facilitate the study of 2D nanomaterial interaction with biomolecules at the molecular level. We discuss the current understanding and progress of 2D nanomaterial interaction with proteins, lipid membranes, and DNA based on molecular dynamics (MD) simulation. In this review, we focus on the 2D graphene nanosheet and briefly discuss other 2D nanomaterials. With the ever-growing computing power, we can image nanoscale processes using MD simulation that are otherwise not observable in experiment. We expect that molecular characterization of the complex behavior between 2D nanomaterials and biomolecules will help fulfill the goal of designing effective 2D nanomaterials as drug delivery platforms.
Collapse
Affiliation(s)
- Serena H Chen
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - David R Bell
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Binquan Luan
- IBM Thomas J. Watson Research, Yorktown Heights, New York 10598, USA.
| |
Collapse
|
6
|
Liu J, Wang S, Yang R, Li L, Liang S, Chen L. Bio-inspired graphene oxide-amino acid cross-linked framework membrane trigger high water permeance and high metal ions rejection. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
7
|
Biswas HS, Bala S, Kundu AK, Saha I, Poddar S, Sarkar S, Mandal P. Tuned synthesis and designed characterization of graphene oxide thin film. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
8
|
Abraham J, Vasu KS, Williams CD, Gopinadhan K, Su Y, Cherian CT, Dix J, Prestat E, Haigh SJ, Grigorieva IV, Carbone P, Geim AK, R Nair R. Reply to: Random interstratification in hydrated graphene oxide membranes and implications for seawater desalination. NATURE NANOTECHNOLOGY 2022; 17:134-135. [PMID: 35058652 DOI: 10.1038/s41565-021-01067-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/30/2021] [Indexed: 06/14/2023]
Affiliation(s)
- Jijo Abraham
- National Graphene Institute, University of Manchester, Manchester, UK
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - Kalangi S Vasu
- National Graphene Institute, University of Manchester, Manchester, UK
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - Christopher D Williams
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - Kalon Gopinadhan
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
| | - Yang Su
- National Graphene Institute, University of Manchester, Manchester, UK
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - Christie T Cherian
- National Graphene Institute, University of Manchester, Manchester, UK
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - James Dix
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - Eric Prestat
- Department of Materials, University of Manchester, Manchester, UK
| | - Sarah J Haigh
- Department of Materials, University of Manchester, Manchester, UK
| | - Irina V Grigorieva
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
| | - Paola Carbone
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - Andre K Geim
- Department of Physics and Astronomy, University of Manchester, Manchester, UK
| | - Rahul R Nair
- National Graphene Institute, University of Manchester, Manchester, UK.
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK.
| |
Collapse
|
9
|
Rajasekhar reddy P, Gogoi A, Anki Reddy K. Effect of oxygen-containing functional groups of layered graphene oxide membrane on the removal of amoxicillin: a molecular dynamics study. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.2000978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- P. Rajasekhar reddy
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam, India
| | - Abhijit Gogoi
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam, India
| | - K. Anki Reddy
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Assam, India
| |
Collapse
|
10
|
Williams CD, Siperstein FR, Carbone P. High-throughput molecular simulations reveal the origin of ion free energy barriers in graphene oxide membranes. NANOSCALE 2021; 13:13693-13702. [PMID: 34477644 DOI: 10.1039/d1nr02169a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Graphene oxide (GO) membranes are highly touted as materials for contemporary separation challenges including desalination, yet understanding of the interplay between their structure and salt rejection is limited. K+ ion permeation through hydrated GO membranes was investigated by combining structurally realistic molecular models and high-throughput molecular dynamics simulations. We show that it is essential to consider the complex GO microstructure to quantitatively reproduce experimentally-derived free energy barriers to K+ permeation for membranes with various interlayer distances less than 1.3 nm. This finding confirms the non-uniformity of GO nanopores and the necessity of the high-throughput approach for this class of material. The large barriers arise due to significant dehydration of K+ inside the membrane, which can have as few as 3 coordinated water molecules, compared to 7 in bulk solution. Thus, even if the membranes have an average pore size larger than the ion's hydrated diameter, the significant presence of pores whose size is smaller than the hydrated diameter creates bottlenecks for the permeation process.
Collapse
Affiliation(s)
- Christopher D Williams
- Department of Chemical Engineering and Analytical Science, School of Engineering, The University of Manchester, Manchester, UK.
| | | | | |
Collapse
|
11
|
Liu Y, Chen Z, Han D, Mao J, Ma J, Zhang Y, Sun H. Bioinspired Soft Robots Based on the Moisture-Responsive Graphene Oxide. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002464. [PMID: 34026430 PMCID: PMC8132057 DOI: 10.1002/advs.202002464] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/09/2020] [Indexed: 05/04/2023]
Abstract
Graphene oxide (GO), which has many oxygen functional groups, is a promising candidate for use in moisture-responsive sensors and actuators due to the strong water-GO interaction and the ultrafast transport of water molecules within the stacked GO sheets. In the last 5 years, moisture-responsive actuators based on GO have shown distinct advantages over other stimuli-responsive materials and devices. Particularly, inspired by nature organisms, various moisture-enabled soft robots have been successfully developed via rational assembly of the GO-based actuators. Herein, the milestones in the development of moisture-responsive soft robots based on GO are summarized. In addition, the working mechanisms, design principles, current achievement, and prospects are also comprehensively reviewed. In particular, the GO-based soft robots are at the forefront of the advancement of automatable smart devices.
Collapse
Affiliation(s)
- Yu‐Qing Liu
- State Key Laboratory of Integrated OptoelectronicsCollege of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun130012China
| | - Zhao‐Di Chen
- State Key Laboratory of Integrated OptoelectronicsCollege of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun130012China
| | - Dong‐Dong Han
- State Key Laboratory of Integrated OptoelectronicsCollege of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun130012China
| | - Jiang‐Wei Mao
- State Key Laboratory of Integrated OptoelectronicsCollege of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun130012China
| | - Jia‐Nan Ma
- State Key Laboratory of Integrated OptoelectronicsCollege of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun130012China
| | - Yong‐Lai Zhang
- State Key Laboratory of Integrated OptoelectronicsCollege of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun130012China
| | - Hong‐Bo Sun
- State Key Laboratory of Integrated OptoelectronicsCollege of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun130012China
- State Key Laboratory of Precision Measurement Technology and InstrumentsDepartment of Precision InstrumentTsinghua UniversityHaidian DistrictBeijing100084China
| |
Collapse
|
12
|
Zhang WH, Yin MJ, Zhao Q, Jin CG, Wang N, Ji S, Ritt CL, Elimelech M, An QF. Graphene oxide membranes with stable porous structure for ultrafast water transport. NATURE NANOTECHNOLOGY 2021; 16:337-343. [PMID: 33479540 DOI: 10.1038/s41565-020-00833-9] [Citation(s) in RCA: 143] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 12/02/2020] [Indexed: 05/25/2023]
Abstract
The robustness of carbon nanomaterials and their potential for ultrahigh permeability has drawn substantial interest for separation processes. However, graphene oxide membranes (GOms) have demonstrated limited viability due to instabilities in their microstructure that lead to failure under cross-flow conditions and applied hydraulic pressure. Here we present a highly stable and ultrapermeable zeolitic imidazolate framework-8 (ZIF-8)-nanocrystal-hybridized GOm that is prepared by ice templating and subsequent in situ crystallization of ZIF-8 at the nanosheet edges. The selective growth of ZIF-8 in the microporous defects enlarges the interlayer spacings while also imparting mechanical integrity to the laminate framework, thus producing a stable microstructure capable of maintaining a water permeability of 60 l m-2 h-1 bar-1 (30-fold higher than GOm) for 180 h. Furthermore, the mitigation of microporous defects via ZIF-8 growth increased the permselectivity of methyl blue molecules sixfold. Low-field nuclear magnetic resonance was employed to characterize the porous structure of our membranes and confirm the tailored growth of ZIF-8. Our technique for tuning the membrane microstructure opens opportunities for developing next-generation nanofiltration membranes.
Collapse
Affiliation(s)
- Wen-Hai Zhang
- Beijing Key Laboratory for Green Catalysis and Separation, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China
| | - Ming-Jie Yin
- Beijing Key Laboratory for Green Catalysis and Separation, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China
| | - Qiang Zhao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Cheng-Gang Jin
- Beijing Key Laboratory for Green Catalysis and Separation, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China
| | - Naixin Wang
- Beijing Key Laboratory for Green Catalysis and Separation, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China
| | - Shulan Ji
- Beijing Key Laboratory for Green Catalysis and Separation, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China
| | - Cody L Ritt
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA.
| | - Quan-Fu An
- Beijing Key Laboratory for Green Catalysis and Separation, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China.
| |
Collapse
|
13
|
Iakunkov A, Talyzin AV. Swelling properties of graphite oxides and graphene oxide multilayered materials. NANOSCALE 2020; 12:21060-21093. [PMID: 33084722 DOI: 10.1039/d0nr04931j] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Graphite oxide (GtO) and graphene oxide (GO) multilayered laminates are hydrophilic materials easily intercalated by water and other polar solvents. By definition, an increase in the volume of a material connected to the uptake of a liquid or vapour is named swelling. Swelling is a property which defines graphite oxides and graphene oxides. Less oxidized materials not capable of swelling should be named oxidized graphene. The infinite swelling of graphite oxide yields graphene oxide in aqueous dispersions. Graphene oxide sheets dispersed in a polar solvent can be re-assembled into multilayered structures and named depending on applications as films, papers or membranes. The multilayered GO materials exhibit swelling properties which are mostly similar to those of graphite oxides but not identical and in some cases surprisingly different. Swelling is a key property of GO materials in all applications which involve the sorption of water/solvents from vapours, immersion of GO into liquid water/solvents and solution based chemical reactions. These applications include sensors, sorption/removal of pollutants from waste waters, separation of liquid and gas mixtures, nanofiltration, water desalination, water-permeable protective coatings, etc. Swelling defines the distance between graphene oxide sheets in solution-immersed GO materials and the possibility for penetration of ions and molecules inside of interlayers. A high sorption capacity of GO towards many molecules and cations is defined by swelling which makes the very high surface area of GO accessible. GtO and GO swelling is a surprisingly complex phenomenon which is manifested in a variety of different ways. Swelling is strongly different for materials produced using the most common Brodie and Hummers oxidation procedures; it depends on the degree of oxidation, ad temperature and pressure conditions. The value of the GO interlayer distance is especially important in membrane applications. Diffusion of solvent molecules and ions is defined by the size of "permeation channels" provided by the swelled GO structure. According to extensive studies performed over the last decade the exact value of the inter-layer distance in swelled GO depends on the nature of solvent, temperature and pressure conditions, and the pH and concentration of solutions and exhibits pronounced aging effects. This review provides insight into the fundamental swelling properties of multilayered GO and demonstrates links to advanced applications of these materials.
Collapse
Affiliation(s)
- Artem Iakunkov
- Department of Physics, Umeå University, SE-901 87 Umeå, Sweden.
| | | |
Collapse
|
14
|
Li W, Zhang L, Zhang X, Zhang M, Liu T, Chen S. Atomic insight into water and ion transport in 2D interlayer nanochannels of graphene oxide membranes: Implication for desalination. J Memb Sci 2020. [DOI: 10.1016/j.memsci.2019.117744] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
15
|
Ritt CL, Werber JR, Deshmukh A, Elimelech M. Monte Carlo Simulations of Framework Defects in Layered Two-Dimensional Nanomaterial Desalination Membranes: Implications for Permeability and Selectivity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:6214-6224. [PMID: 31066551 DOI: 10.1021/acs.est.8b06880] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two-dimensional nanomaterial (2-D NM) frameworks, especially those comprising graphene oxide, have received extensive research interest for membrane-based separation processes and desalination. However, the impact of horizontal defects in 2-D NM frameworks, which stem from nonuniform deposition of 2-D NM flakes during layer build-up, has been almost entirely overlooked. In this work, we apply Monte Carlo simulations, under idealized conditions wherein the vertical interlayer spacing allows for water permeation while perfectly excluding salt, on both the formation of the laminate structure and molecular transport through the laminate. Our simulations show that 2-D NM frameworks are extremely tortuous (tortuosity ≈103), with water permeability decreasing from 20 to <1 L m-2 h-1 bar-1 as thickness increased from 8 to 167 nm. Additionally, we find that framework defects allow salt to percolate through the framework, hindering water-salt selectivity. 2-D NM frameworks with a packing density of 75%, representative of most 2-D NM membranes, are projected to achieve <92% NaCl rejection at a water permeability of <1 L m-2 h-1 bar-1, even with ideal interlayer spacing. A high packing density of 90%, which to our knowledge has yet to be achieved, could yield comparable performance to current desalination membranes. Maximizing packing density is therefore a critical technical challenge, in addition to the already daunting challenge of optimizing interlayer spacing, for the development of 2-D NM membranes.
Collapse
Affiliation(s)
- Cody L Ritt
- Department of Chemical and Environmental Engineering , Yale University , New Haven , Connecticut 06520-8286 , United States
| | - Jay R Werber
- Department of Chemical and Environmental Engineering , Yale University , New Haven , Connecticut 06520-8286 , United States
| | - Akshay Deshmukh
- Department of Chemical and Environmental Engineering , Yale University , New Haven , Connecticut 06520-8286 , United States
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering , Yale University , New Haven , Connecticut 06520-8286 , United States
| |
Collapse
|
16
|
Williams CD, Carbone P, Siperstein FR. In Silico Design and Characterization of Graphene Oxide Membranes with Variable Water Content and Flake Oxygen Content. ACS NANO 2019; 13:2995-3004. [PMID: 30785717 PMCID: PMC7005941 DOI: 10.1021/acsnano.8b07573] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 02/20/2019] [Indexed: 06/09/2023]
Abstract
Graphene oxide (GO) membranes offer exceptional promise for certain aqueous separation challenges, such as desalination. Central to unlocking this promise and optimizing performance for a given separation is the establishment of a detailed molecular-level understanding of how the membrane's composition affects its structural and transport properties. This understanding is currently lacking, in part due to the fact that, until recently, molecular models with a realistic distribution of oxygen functionalities and interlayer flake structure were unavailable. To understand the effect of composition on the properties of GO membranes, models with water contents and oxygen contents, varying between 0% and 40% by weight, were prepared in this work using classical molecular dynamics simulations. The change in membrane interlayer distance distribution, water connectivity, and water diffusivity with water and oxygen content was quantified. Interlayer distance distribution analysis showed that the swelling of GO membranes could be controlled by separately tuning both the flake oxygen content and the membrane water content. Water-molecule cluster analysis showed that a continuous and fully connected network of water nanopores is not formed until the water content reaches ∼20%. The diffusivity of water in the membrane was also found to strongly depend on both the water and the oxygen content. These insights help understand the structure and transport properties of GO membranes with sub-nanometer interlayer distances and could be exploited to enhance the performance of GO membranes for aqueous separation applications. More broadly, the high-throughput in silico approach adopted could be applied to other nanomaterials with intrinsic non-stoichiometry and structural heterogeneity.
Collapse
|
17
|
Carey T, Williams CD, McArthur DJ, Malkinson T, Thompson OR, Baidak A, Murtagh L, Glodan G, Morgan SP, Banford AW. Removal of Cs, Sr, U and Pu species from simulated nuclear waste effluent using graphene oxide. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-5931-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|