File(s) under permanent embargo
Relating forward water and reverse salt fluxes to membrane porosity and tortuosity in forward osmosis: CFD modelling
journal contribution
posted on 2020-06-15, 00:00 authored by M Kahrizi, J Lin, G Ji, Lingxue KongLingxue Kong, C Song, Ludovic Dumee, S Sahebi, Shuaifei ZhaoShuaifei Zhao© 2020 Elsevier B.V. A 2D finite element model was developed to describe the forward osmosis (FO) process under steady-state conditions. Two approaches are applied to study forward water and reverse salt fluxes. In the first approach, the mathematical equations are formulated based on the bulk concentration differences between the feed and the draw solutions. Transfer resistances arising from internal concentration polarization, external concentration polarization and reverse salt flux are considered. The second approach is based on a complete computational fluid dynamic (CFD) model, both the constrictivity factor and the sorption coefficient are considered to enhance the accuracy of prediction. The CFD model provides a more realistic representation of the FO process than the first simple approach. Our CFD model shows that the concentration profile within the membrane support layer is a result of the coupled interaction between the dilutive internal concentration polarization and the reverse solute diffusion from the draw. Increasing porosity or decreasing tortuosity is not always desirable since it will also increase reverse salt flux. Forward water and reverse salt fluxes are independent on tortuosity or porosity alone, but dependent on their ratios. This work offers significant insights into developing high performance FO membranes with suitable porosity and tortuosity, thereby reducing internal concentration polarization and reverse salt diffusion.
History
Journal
Separation and Purification TechnologyVolume
241Article number
116727Pagination
1 - 13Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
1383-5866eISSN
1873-3794Language
engPublication classification
C1 Refereed article in a scholarly journalUsage metrics
Categories
Keywords
Forward osmosisConcentration polarizationComputational fluid dynamicsMembrane porosityWater fluxReverse salt fluxScience & TechnologyTechnologyEngineering, ChemicalEngineeringINTERNAL CONCENTRATION POLARIZATIONDRAW SOLUTE PERMEATIONSEPARATION PERFORMANCESUBLAYER STRUCTUREFO MEMBRANEDESALINATIONBEHAVIORFEEDCOEFFICIENTFABRICATIONMembrane and Separation Technologies
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC