Estimation of electrical parameters inside nanofiltration membranes in various electrolyte solutions by dielectric spectroscopy analysis

Zhao, Kongshuang; Lü, Qing; Su, Wenjuan

doi:10.1039/c4ra13598a

Cited by 5 publications

(3 citation statements)

References 38 publications

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“…Electrical parameters are widely applied for the evaluation of the quality of agro-products and food, 18,19 interfacial property of electrolyte solutions, 20 and characterization of membranes. 21,22 Zywica et al 23 suggested there was a linear correlation between total soluble solids in reconstituted apple juice and electrical parameters, which concluded that it is possible to evaluate the concentrations of apple purées in pulpy juices and beverages by electro-analytical method. Additionally, estimation of the quality of bighead carp (Aristichthys nobilis) during chilling storage 24 and determination of the degree of dispersion of fat globules in the homogenization process 25 have also been successfully conducted by measuring electrical parameters.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the degree of chitosan deacetylation via induced-electrical properties

Guo

Yang

et al. 2017

RSC Adv.

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Section: Introductionmentioning

confidence: 99%

Evaluation of the degree of chitosan deacetylation via induced-electrical properties

Guo

Yang

et al. 2017

RSC Adv.

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“…Electrostatic repulsion has also been shown to be an important variable for minimizing fouling [11,61]. The TFC QI membrane has a much higher charge density (calculated to be about 1,640 mol/m 3 , see Section 3 in the Data in Brief) than the NF90 membrane (estimated around 1 mol/m 3 [62]) and thereby should induce greater electrostatic repulsion, further contributing to its lower fouling propensity. Lastly, research has shown that periodic nanostructure reduces fouling [15].…”

Section: Discussion Of Fouling Propensitymentioning

confidence: 99%

Evaluation of a nanoporous lyotropic liquid crystal polymer membrane for the treatment of hydraulic fracturing produced water via cross-flow filtration

Dischinger

Rosenblum

Noble

et al. 2019

Journal of Membrane Science

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Current commercial nanofiltration and reverse osmosis membranes are limited in scope and performance due to their physicochemical properties. Desalination of hydraulic fracturing wastewater poses a particular challenge to membrane filtration given the high concentrations of both organic compounds and salts present in these waters. The recently-developed nanoporous, bicontinuous cubic, lyotropic liquid crystal, thin-film-composite polymer membrane (TFC QI membrane), having unique physicochemical properties, enables an alternative treatment of hydraulic fracturing wastewater. Specifically, the TFC QI membrane recovers the organic compounds from this high-salinity wastewater, enabling biodegradation to occur after desalination. However, other performance criteria must be demonstrated for a membrane to reach application. The work presented herein demonstrates the stable performance of the TFC QI membrane during 66 h of cross-flow filtration of hydraulic fracturing produced water. Compared to the commercial NF90 membrane, the TFC QI membrane recovered a larger portion of the organic compounds, had a higher thickness-normalized water flux, and fouled less. The combination of the TFC QI membrane's selectivity with its reduced fouling propensity makes possible a treatment for hydraulic fracturing wastewater and other complex aqueous streams inaccessible by most commercial membranes, motivating the further study and development of the TFC QI membrane.

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“…Passage of Single Salts and Associated Selectivities. Polymeric NF membranes such as the pristine NF270 are characterized by sub-nm scale effective pore size (0.5−2 nm), 34 and low dielectric constant in the pores 49,50 relative to unconfined water. These properties lead to the preferential passage of monovalent ions over bivalent ions because the strength of both steric and dielectric exclusion increases with the valence of ions regardless of their charge sign.…”

Section: Hydrophilicity and Surfacementioning

confidence: 99%

Tuning the Ion-Selectivity of Thin-Film Composite Nanofiltration Membranes by Molecular Layer Deposition of Alucone

Chaudhury

Wormser

Harari

et al. 2020

ACS Appl. Mater. Interfaces

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This work addresses a key challenge of tailoring the ion selectivity of a thin-film composite nanofiltration membrane to a specific application, such as water softening, without altering the water permeability. We modified the active surface of a commercial NF270 membrane by molecular layer deposition (MLD) of ethylene glycol-Al (EG-alucone). With increasing deposition cycles, we found that the MLD precursors first infiltrated and deposited in the active layer of NF270, then inflated the active layer, and finally deposited on the surface as a distinct EG-alucone layer. The deposition process changed the morphology of the membrane active layer and decreased the overall density of its fixed negative charge by embedding the positively charged EGalucone. Filtration experiments revealed that these modifications affected the ion separation properties of the membrane without significantly hindering the water permeability. Specifically, the permeation of Na + increased relative to that of Mg 2+ , as indicated by the permselectivity of Na + salts over Mg 2+ salts. The changes in permselectivities with an increasing number of MLD cycles were rationalized using the dielectric, steric, and electrostatic ion exclusion mechanisms, which are related to the membrane material, pore size, and fixed charge, respectively. These relations open a path for the rational design of nanofiltration membranes with tailored selectivity by tuning the properties of the MLD layer. Filtration results of natural brackish groundwater using the MLD modified membranes agreed with the single salt experiments. As a result, water hardness was 26% lower for the permeate obtained using the MLD-modified membranes, which were found stable even during a 24 h filtration run. These results highlight the practical potential of this approach in enhancing water softening efficiency.

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Estimation of electrical parameters inside nanofiltration membranes in various electrolyte solutions by dielectric spectroscopy analysis

Cited by 5 publications

References 38 publications

Evaluation of the degree of chitosan deacetylation via induced-electrical properties

Evaluation of the degree of chitosan deacetylation via induced-electrical properties

Evaluation of a nanoporous lyotropic liquid crystal polymer membrane for the treatment of hydraulic fracturing produced water via cross-flow filtration

Tuning the Ion-Selectivity of Thin-Film Composite Nanofiltration Membranes by Molecular Layer Deposition of Alucone

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