A critical review of fouling of reverse osmosis membranes

Potts, D.E.; Ahlert, Robert C.; Wang, S.S.

doi:10.1016/s0011-9164(00)88642-7

Cited by 247 publications

(90 citation statements)

References 36 publications

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“…The successful operation of membrane processes generally requires development of an appropriate pretreatment strategy [9]. It is obvious that reducing NOM concentration in feed water may be the first choice for pretreatment to lessen NOM fouling.…”

Section: Effect Of Edta On Nov Foulingmentioning

confidence: 99%

“…Effective membrane cleaning is often just as important as pretreatment processes for efficient operation of NF membrane systems [9]. The effectiveness of cleaning is greatly influenced by the choice of cleaning solutions.…”

Section: Effect Of Edta On Cleaning Of Nom-fouled Membranementioning

confidence: 99%

“…A wide spectrum of constituents in process waters contribute to fouling. These include dissolved and macromolecular organic substances, sparingly soluble inorganic compounds, colloidal and suspended particles, and microorganisms [2,9].…”

Section: Introductionmentioning

confidence: 99%

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Fouling of nanofiltration membranes

1998

Membrane Technology

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The role of chemical and physical interactions in natural organic matter (NOM) fouling of nanofiltration membranes is systematically investigated. Results of fouling experiments with three humic acids demonstrate that membrane fouling increases with increasing electrolyte (NaC1) concentration, decreasing solution pH, and addition of divalent cations (Ca2+). At fixed solution ionic strength, the presence of calcium ions, at concentrations typical of those found in natural waters, has a marked effect on membrane fouling. Divalent cations interact specifically with humic carboxyl functional groups and, thus, substantially reduce humic charge and the electrostatic repulsion between humic macromolecules. Reduced NOM interchain repulsion results in increased NOM deposition on the membrane surface and formation of a densely packed fouling layer. In addition to the aforementioned chemical effects, results show that NOM fouling rate increases substantially with increasing initial permeation rate. It is demonstrated that the rate of fouling is controlled by an interplay between permeation drag and electrostatic double layer repulsion; that is, NOM fouling of NF membranes involves interrelationship (coupling) between physical and chemical interactions. The addition of a strong chelating agent (EDTA) to feed water reduces NOM fouling significantly by removing free and NOM-complexed calcium ions. EDTA treatment of NOM-fouled membranes also improves the cleaning efficiency dramatically by disrupting the fouling layer structure through a ligand exchange reaction between EDTA and NOM-calcium complexes.

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Section: Effect Of Edta On Nov Foulingmentioning

confidence: 99%

Section: Effect Of Edta On Cleaning Of Nom-fouled Membranementioning

confidence: 99%

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Fouling of nanofiltration membranes

1998

Membrane Technology

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“…As a result of water crossing the membrane, the solute is concentrated on the feed side of the membrane surface and diluted on the permeate side. As, an asymmetric membrane is used in RO which comprises of a thin dense layer on top of a porous supported layer, concentration polarization occurs externally on the dense layer and internally on the supported layer side 20, 21 .…”

Section: Introductionmentioning

confidence: 99%

Reverse osmosis as one-step wastewater treatment: a case study on groundwater pollution

Ali

Rehman

Younas

et al. 2015

Polish Journal of Chemical Technology

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The present case study is focused on performance evaluation of a Reverse Osmosis (RO) membrane based pilot plant to treat the ground/surface drinking water sources polluted by fl ood, rivers and/or canals. The RO plant was designed, fabricated and then operated with polluted water. Two feed water samples having a TDS of 2.000 mg . L -1 and 10.000 mg . L -1 respectively, were taken and analyzed for physical, chemical and microbiological contaminants. The RO plant was run once through over a span of 100 hrs at an operating pressure of 15 bar. TDS rejections were found to be more than 94% while permeate fl ux was measured to be 25.82 L . m -2 . hr -1 to 40.55 L . m -2 . hr -1 . Results show that RO plant has a potential to remove physical, chemical and microbiological contaminants like Total Coliform and E. Coli in one step.

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“…Mathematical models for the mass transport process through RO membranes have been developed and reviewed in detail in the literature [1][2][3][4][5][6][7][8][9][10][11]. These models can be divided into three main groups: the irreversible thermodynamic models, where the local fluxes of solute and solvent are related to the chemical potential differences across the membrane [12][13][14]; the porous flow model, which assumes that water both diffuses and advects through the membrane pores [1,15,16]; and the solution-diffusion model, which assumes that both water and solutes diffuse between the interstitial spaces of the membrane polymer chains [11,17,18].…”

Section: Introductionmentioning

confidence: 99%

Effectiveness-mass transfer units (ε-MTU) model of a reverse osmosis membrane mass exchanger

Banchik

Sharqawy

Lienhard

2014

Journal of Membrane Science

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A strong analogy exists between heat exchangers and osmotic mass exchangers. The effectiveness -number of transfer units (-NTU) method is well-known for the sizing and rating of heat exchangers. A similar method, called the effectiveness -mass transfer units (ε-MTU) method, is developed for reverse osmosis (RO) mass exchangers. Governing equations for an RO mass exchanger are nondimensionalized assuming ideal membrane characteristics and a linearized form of the osmotic pressure function for seawater. A closed form solution is found which relates three dimensionless groups: the number of mass transfer units, which is an effective size of the exchanger; a pressure ratio, which relates osmotic and hydraulic pressures; and the recovery ratio, which is the ratio of permeate to inlet feed flow rates. A novel performance parameter, the effectiveness of an RO exchanger, is defined as a ratio of the recovery ratio to the maximum recovery ratio. A one-dimensional numerical model is developed to correct for the effects of feed-side external concentration polarization and nonlinearities in osmotic pressure as a function of salinity. A comparison of model results to experimental data found in the literature resulted in an average error of less than 7.8%. The analytical ε-MTU model can be used for design or performance evaluation of RO membrane mass exchangers. Keywords

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A critical review of fouling of reverse osmosis membranes

Cited by 247 publications

References 36 publications

Fouling of nanofiltration membranes

Fouling of nanofiltration membranes

Reverse osmosis as one-step wastewater treatment: a case study on groundwater pollution

Effectiveness-mass transfer units (ε-MTU) model of a reverse osmosis membrane mass exchanger

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