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An improved perm-selectivity prediction of forward osmosis membrane by incorporating the effect of the surface charge on the solute partitioning. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Cheng C, Jiang G, Garvey CJ, Wang Y, Simon GP, Liu JZ, Li D. Ion transport in complex layered graphene-based membranes with tuneable interlayer spacing. SCIENCE ADVANCES 2016; 2:e1501272. [PMID: 26933689 PMCID: PMC4758742 DOI: 10.1126/sciadv.1501272] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/02/2015] [Indexed: 05/22/2023]
Abstract
Investigation of the transport properties of ions confined in nanoporous carbon is generally difficult because of the stochastic nature and distribution of multiscale complex and imperfect pore structures within the bulk material. We demonstrate a combined approach of experiment and simulation to describe the structure of complex layered graphene-based membranes, which allows their use as a unique porous platform to gain unprecedented insights into nanoconfined transport phenomena across the entire sub-10-nm scales. By correlation of experimental results with simulation of concentration-driven ion diffusion through the cascading layered graphene structure with sub-10-nm tuneable interlayer spacing, we are able to construct a robust, representative structural model that allows the establishment of a quantitative relationship among the nanoconfined ion transport properties in relation to the complex nanoporous structure of the layered membrane. This correlation reveals the remarkable effect of the structural imperfections of the membranes on ion transport and particularly the scaling behaviors of both diffusive and electrokinetic ion transport in graphene-based cascading nanochannels as a function of channel size from 10 nm down to subnanometer. Our analysis shows that the range of ion transport effects previously observed in simple one-dimensional nanofluidic systems will translate themselves into bulk, complex nanoslit porous systems in a very different manner, and the complex cascading porous circuities can enable new transport phenomena that are unattainable in simple fluidic systems.
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Affiliation(s)
- Chi Cheng
- Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia
| | - Gengping Jiang
- Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia
| | - Christopher J. Garvey
- Australia Nuclear Science and Technology Organization, Sydney, New South Wales 2232, Australia
| | - Yuanyuan Wang
- Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia
| | - George P. Simon
- Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia
- Monash Centre for Atomically Thin Materials, Monash University, Melbourne, Victoria 3800, Australia
| | - Jefferson Z. Liu
- Monash Centre for Atomically Thin Materials, Monash University, Melbourne, Victoria 3800, Australia
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria 3800, Australia
- Corresponding author. E-mail: (D.L.); (J.Z.L.)
| | - Dan Li
- Department of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia
- Monash Centre for Atomically Thin Materials, Monash University, Melbourne, Victoria 3800, Australia
- Corresponding author. E-mail: (D.L.); (J.Z.L.)
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Weidman JL, Mulvenna RA, Boudouris BW, Phillip WA. Nanostructured Membranes from Triblock Polymer Precursors as High Capacity Copper Adsorbents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11113-23. [PMID: 26391625 DOI: 10.1021/acs.langmuir.5b01605] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Membrane adsorbers are a proposed alternative to packed beds for chromatographic separations. To date, membrane adsorbers have suffered from low binding capacities and/or complex processing methodologies. In this work, a polyisoprene-b-polystyrene-b-poly(N,N-dimethylacrylamide) (PI-PS-PDMA) triblock polymer is cast into an asymmetric membrane that possesses a high density of nanopores (d ∼ 38 nm) at the upper surface of the membrane. Exposing the membrane to a 6 M aqueous hydrochloric acid solution converts the PDMA brushes that line the pore walls to poly(acrylic acid) (PAA) brushes, which are capable of binding metal ions (e.g., copper ions). Using mass transport tests and static binding experiments, the saturation capacity of the PI-PS-PAA membrane was determined to be 4.1 ± 0.3 mmol Cu(2+) g(-1). This experimental value is consistent with the theoretical binding capacity of the membranes, which is based on the initial PDMA content of the triblock polymer precursor and assumes a 1:1 stoichiometry for the binding interaction. The uniformly sized nanoscale pores provide a short diffusion length to the binding sites, resulting in a sharp breakthrough curve. Furthermore, the membrane is selective for copper ions over nickel ions, which permeate through the membrane over 10 times more rapidly than copper during the loading stage. This selectivity is present despite the fact that the sizes of these two ions are nearly identical and speaks to the chemical selectivity of the triblock polymer-based membrane. Furthermore, addition of a pH 1 solution releases the bound copper rapidly, allowing the membrane to be regenerated and reused with a negligible loss in binding capacity. Because of the high binding capacities, facile processing method implemented, and ability to tailor further the polymer brushes lining the pore walls using straightforward coupling reactions, these membrane adsorbers based on block polymer precursors have potential as a separation media that can be designed to a variety of specific applications.
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Affiliation(s)
- Jacob L Weidman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Ryan A Mulvenna
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Bryan W Boudouris
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - William A Phillip
- Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
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Bian L, Fang Y, Wang X. Experimental investigation into the transmembrane electrical potential of the forward osmosis membrane process in electrolyte solutions. MEMBRANES 2014; 4:275-86. [PMID: 24957177 PMCID: PMC4085625 DOI: 10.3390/membranes4020275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/29/2014] [Accepted: 06/10/2014] [Indexed: 11/16/2022]
Abstract
The transmembrane electrical potential (TMEP) in a forward osmosis membrane process with a single electrolyte solution as the draw and feed solutions was investigated by experiments. The effects of membrane orientation, the electrolyte species (KCl, NaCl, MgCl2, and CaCl2), concentration and concentration ratio of solutions at both sides of membrane on water flux and TMEP were investigated. The results showed that the TMEPs at different membrane orientation cannot completely coincide, which confirmed the effect of membrane asymmetry. The ion diffusion coefficients significantly affected the TMEP across the membrane, with different patterns for different electrolytes and concentrations.
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Affiliation(s)
- Lixia Bian
- Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
| | - Yanyan Fang
- Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
| | - Xiaolin Wang
- Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
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Shen JN, Yu CC, Ruan HM, Gao CJ, Van der Bruggen B. Preparation and characterization of thin-film nanocomposite membranes embedded with poly(methyl methacrylate) hydrophobic modified multiwalled carbon nanotubes by interfacial polymerization. J Memb Sci 2013. [DOI: 10.1016/j.memsci.2013.04.018] [Citation(s) in RCA: 184] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Fang Y, Bian L, Wang X. Understanding membrane parameters of a forward osmosis membrane based on nonequilibrium thermodynamics. J Memb Sci 2013. [DOI: 10.1016/j.memsci.2013.02.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wu J, Gerstandt K, Zhang H, Liu J, Hinds BJ. Electrophoretically induced aqueous flow through single-walled carbon nanotube membranes. NATURE NANOTECHNOLOGY 2012; 7:133-9. [PMID: 22245860 PMCID: PMC4134328 DOI: 10.1038/nnano.2011.240] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 12/01/2011] [Indexed: 05/17/2023]
Abstract
Electrophoresis, the motion of charged species through liquids and pores under the influence of an external electric field, has been the principle source of chemical pumping for numerous micro- and nanofluidic device platforms. Recent measurements of ion currents through single or few carbon nanotube channels have yielded values of ion mobility that range from close to the bulk mobility to values that are two to seven orders of magnitude higher than the bulk mobility. However, these experiments cannot directly measure ion flux. Experiments on membranes that contain a large number of nanotube pores allow the ion current and ion flux to be measured independently. Here, we report that the mobilities of ions within such membranes are approximately three times higher than the bulk mobility. Moreover, the induced electro-osmotic velocities are four orders of magnitude faster than those measured in conventional porous materials. We also show that a nanotube membrane can function as a rectifying diode due to ionic steric effects within the nanotubes.
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Affiliation(s)
- Ji Wu
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, USA
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Wang X, Fang Y, Tu C, Van der Bruggen B. Modelling of the separation performance and electrokinetic properties of nanofiltration membranes. INT REV PHYS CHEM 2012. [DOI: 10.1080/0144235x.2012.659049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Tu CH, Fang YY, Zhu J, Van der Bruggen B, Wang XL. Free energies of the ion equilibrium partition of KCl into nanofiltration membranes based on transmembrane electrical potential and rejection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10274-10281. [PMID: 21728362 DOI: 10.1021/la200219k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The free energies of ion equilibrium partition between an aqueous KCl solution and nanofiltration (NF) membranes were investigated on the basis of the relationship of the transmembrane electrical potential (TMEP) and rejection. The measurements of TMEP and rejection were performed for Filmtec NF membranes in KCl solutions over a wide range of salt concentrations (1-60 mol·m(-3)) and pH values (3-10) at the feed side, with pressure differences in the range 0.1-0.6 MPa. The reflection coefficient and transport number, which were used to obtain the distribution coefficients on basis of irreversible thermodynamics, were fitted by the two-layer model with consideration of the activity coefficient. Evidence for dielectric exclusion under the experimental conditions was obtained by analyzing the rejection of KCl at the isoelectric point. The free energies were calculated, and the contribution of the electrostatic effect, dielectric exclusion, steric hindrance, and activity coefficient on the ion partitioning is elucidated. It is clearly demonstrated that the dielectric exclusion plays a central role.
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Affiliation(s)
- Cong-Hui Tu
- State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, PR China
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