Prediction of Membrane Separation Characteristics by Pore Distribution Measurements and Surface Force-Pore Flow Model

Bhattacharyya, Dibakar; Jevtitch, M.; Schrodt, J. Thomas; Weather, G. Fair

doi:10.1080/00986448608911739

Cited by 24 publications

(8 citation statements)

References 19 publications

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“…Water molecules can accomplish ultrafast and frictionless flow in the CNT pore channel due to weak interaction between a water molecule and the smooth hydrophobic carbon wall and the formed ordered hydrogen bonds. , Theoretically, the CNT membrane can achieve a 600 times higher water flow rate than the current commercial PA membrane . Moreover, the CNT pore size should be less than 0.59 nm for achieving a high NaCl rejection, which is similar to a commercial seawater RO membrane (around 0.6 nm) with high salt rejection (>99.8%). , However, it is still a great challenge to fabricate such a subnanometric CNT membrane.…”

Section: Introductionmentioning

confidence: 99%

Incorporation of Silver-Embedded Carbon Nanotubes Coated with Tannic Acid into Polyamide Reverse Osmosis Membranes toward High Permeability, Antifouling, and Antibacterial Properties

Zhao

Zhang

et al. 2021

ACS Sustainable Chem. Eng.

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In this work, tannic acid (TA)-functionalized carbon nanotubes (CNT@TA) were synthesized by hydrogen bond and π−π stacking interactions. CNT@TA embedded with silver nanoparticles (Ag-CNT@TA) was obtained by in situ reducing silver ammonia ions in the pore channels of CNT@TA. CNT@TA and Ag-CNT@TA were added into the polyamide (PA) layer by interfacial polymerization to fabricate high-performance nanocomposite reverse osmosis membranes. The results show that the functionalized CNTs can be uniformly distributed in the PA matrix with random orientations. A loose PA separation layer was obtained by introducing CNT@TA. Correspondingly, abundant new water channels were formed. Compared with the pure PA membrane, the water permeability (4.81 L m −2 h −1 bar −1 ) of the nanocomposite membrane is enhanced by 49.8% without any loss in NaCl rejection (99.3%). The membrane exhibits satisfactory chemical-and bio-fouling resistances to bovine serum albumin and Escherichia coli as model foulants. The high bactericidal rate should be ascribed to the formation of the TA coating and confined Ag nanoparticles in CNT channels. The confined structure effectively avoids the leaching out of the Ag nanoparticles and keeps the persistence of the antibacterial property. The excellent compatibility between the CNTs and the polyamide matrix endows the membrane with long-term performance stability.

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Section: Introductionmentioning

confidence: 99%

Incorporation of Silver-Embedded Carbon Nanotubes Coated with Tannic Acid into Polyamide Reverse Osmosis Membranes toward High Permeability, Antifouling, and Antibacterial Properties

Zhao

Zhang

et al. 2021

ACS Sustainable Chem. Eng.

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“…Theoretically, for sodium chloride (NaCl) rejection, the inlet pore size diameter of CNTs should be as low as 0.59 nm . The pore size of commercial seawater reverse osmosis (SWRO) polymeric membranes with high rejection (above 99.8%) is also distributed around 0.6 nm . These are the primary reasons why there are few scientific reports of vertically aligned CNTs membranes that show high salt rejection …”

Section: Introductionmentioning

confidence: 99%

Experimental Evidence of Rapid Water Transport through Carbon Nanotubes Embedded in Polymeric Desalination Membranes

Lee

Kim

Cho

et al. 2014

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132

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As water molecules permeate ultrafast through carbon nanotubes (CNTs), many studies have prepared CNTs-based membranes for water purification as well as desalination, particularly focusing on high flux membranes. Among them, vertically aligned CNTs membranes with ultrahigh water flux have been successfully demonstrated for fundamental studies, but they lack scalability for bulk production and sufficiently high salt rejection. CNTs embedded in polymeric desalination membranes, i.e., polyamide thin-film composite (TFC) membranes, can improve water flux without any loss of salt rejection. This improved flux is achieved by enhancing the dispersion properties of CNTs in diamine aqueous solution and also by using cap-opened CNTs. Hydrophilic CNTs were prepared by wrapping CNT walls via bio-inspired surface modification using dopamine solution. Cap-opening of pristine CNTs is performed by using a thermo-oxidative process. As a result, hydrophilic, cap-opened CNTs-embedded polyamide TFC membranes are successfully prepared, which show much higher water flux than pristine polyamide TFC membrane. On the other hand, less-disperse, less cap-opened CNTs-embedded TFC membranes do not show any flux improvement and rather lead to lower salt rejection properties.

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“…These include adsorption of gases such as CO 2 and N 2 [4], liquid chromotography and ®ltration data correlated to pore size [5]. The results indicate that a normal or a log-normal distribution of pore sizes is a good assumption in most cases.…”

Section: Introductionmentioning

confidence: 90%

The effect of pore size distribution on the separation efficiency in surface force pore-flow model-system: isopropanol-water

Gupta

Hashim

Cui

1999

Bioprocess Engineering

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The surface force pore-¯ow (SFPF) model is based on solute-membrane material interactions at the membrane-solution interface. It has been used to model the transport of solute and solvent through membranes under the in¯uence of such forces and to determine separation ef®ciency based on the assumption of circular pores. It is evident from the model that the pore diameter has a strong bearing upon the separation ef®ciency and the mean separation ef®ciency can be determined from the pore size distribution. In this work a Monte Carlo simulation technique has been employed to generate a large number of sample pores from the mean and the standard deviation. The Gaussian distribution has been used to determine the separation ef®ciency in the SFPF model. The results have been compared with the available data for isopropanol/cellulose acetate/water system and the predicted values agree well with the published data. List of symbolsA constant characterizing electrostatic repulsive force, m B constant characterizing van der Waals attractive force, m 3 b frictional function, dimensionless C A dimensionless solute concentration at the pore outlet c A molar solute concentration, mol/m 3 D constant characterizing steric repulsion at the interface, m D w Stokes radius of water, m D AB diffusivity of solute in water, m 2 /s f solute separation based on the solute concentration in the bulk feed, dimensionless f H true value of solute separation by membrane pore, dimensionless f H areav as de®ned in Eq. (26) f H diav as de®ned in Eq. (27) k mass transfer coef®cient, m/s k H random variate R a radius of the water channel in the membrane pore, m R b membrane pore radius, m R blo pore radius, m as de®ned in Eq. (20) R bhi pore radius, m as de®ned in Eq. (21) R bmean average pore radius, m m s permeation velocity, m/sGreek letters aq dimensionless solution velocity pro®le in a cylindrical pore b 1 dimensionless solution velocity b 2 dimensionless operating pressure k f DaR b q solution density, kgam 3 , or dimensionless radial distance r standard deviation of the normal pore size distribution, m g viscosity of the solution in the pore, Pa s / potential in the interfacial force ®eld, J/mol

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Prediction of Membrane Separation Characteristics by Pore Distribution Measurements and Surface Force-Pore Flow Model

Cited by 24 publications

References 19 publications

Incorporation of Silver-Embedded Carbon Nanotubes Coated with Tannic Acid into Polyamide Reverse Osmosis Membranes toward High Permeability, Antifouling, and Antibacterial Properties

Incorporation of Silver-Embedded Carbon Nanotubes Coated with Tannic Acid into Polyamide Reverse Osmosis Membranes toward High Permeability, Antifouling, and Antibacterial Properties

Experimental Evidence of Rapid Water Transport through Carbon Nanotubes Embedded in Polymeric Desalination Membranes

The effect of pore size distribution on the separation efficiency in surface force pore-flow model-system: isopropanol-water

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