Flow and fouling in membrane filters: effects of membrane morphology

Sanaei, Pejman; Cummings, L. J.

doi:10.1017/jfm.2017.102

Cited by 39 publications

(32 citation statements)

References 27 publications

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“…deposition within pores. Following earlier work [27], we propose a simple advection and deposition model for the particle concentration C(X, Y, T ) within pores,…”

Section: B Governing Equationsmentioning

confidence: 99%

“…This model comes from an asymptotic analysis of the full advection and diffusion equation for a suspension of small particles passing through a slender tube; the detailed justification can be found in Sanaei and Cummings [27]. The dimensional constant Λ measures the strength of attraction between the particles and the pore wall that gives rise to the deposition.…”

Section: B Governing Equationsmentioning

confidence: 99%

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Modeling and design optimization for pleated membrane filters

et al. 2020

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Pleated membrane filters, which offer larger surface area to volume ratios than unpleated membrane filters, are used in a wide variety of applications. However, the performance of the pleated filter, as characterized by a flux-throughput plot, indicates that the equivalent unpleated filter provides better performance under the same pressure drop. Earlier work (Sanaei & Cummings 2016) used a highly-simplified membrane model to investigate how the pleating effect and membrane geometry affect this performance differential. In this work, we extend this line of investigation and use asymptotic methods to couple an outer problem for the flow within the pleated structure to an inner problem that accounts for the pore structure within the membrane. We use our new model to formulate and address questions of optimal membrane design for a given filtration application. *

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“…deposition within pores. Following earlier work [27], we propose a simple advection and deposition model for the particle concentration C(X, Y, T ) within pores,…”

Section: B Governing Equationsmentioning

confidence: 99%

Section: B Governing Equationsmentioning

confidence: 99%

Modeling and design optimization for pleated membrane filters

et al. 2020

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“…Early studies characterized particle trapping and clogging in filters through flow rate measurements. The efficiency and lifetime of a filter was obtain though theoretical models and/or macroscopic measurements [10][11][12][13][14][15][16][17]. Different theoretical models have been developed considering various blocking mechanisms and some predictions of the time evolution of the flow rate were provided [18].…”

Section: Introductionmentioning

confidence: 99%

Growth of clogs in parallel microchannels

Sauret

Somszor²,

Villermaux

et al. 2018

Phys. Rev. Fluids

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During the transport of colloidal suspensions in microchannels, the deposition of particles can lead to the formation of clogs, typically at constrictions. Once a clog is formed in a microchannel, advected particles form an aggregate upstream from the site of the blockage. This aggregate grows over time, which leads to a dramatic reduction of the flow rate. In this paper, we present a model that predicts the growth of the aggregate formed upon clogging of a microchannel. We develop an analytical description that captures the time evolution of the volume of the aggregate, as confirmed by experiments performed using a pressure-driven suspension flow in a microfluidic device. We show that the growth of the aggregate increases the hydraulic resistance in the channel and leads to a drop in the flow rate of the suspensions. We then derive a model for the growth of aggregates in multiple parallel microchannels where the clogging events are described using a stochastic approach. The aggregate growths in the different channels are coupled. Our work illustrates the critical influence of clogging events on the evolution of the flow rate in microchannels. The coupled dynamics of the aggregates described here for parallel channels is key to bridge clogging at the pore scale with macroscopic observations of the flow rate evolution at the filter scale.

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“…This is due to the lack of quantitative understanding of the impact of morphological and/or topological modifications on membrane fouling at prescribed operating conditions. While (semi-)analytical methods can provide general guiding principles and basic process understanding for highly idealized systems (Battiato 2012;Sanaei et al 2016;Ling et al 2016;Kang et al 2007b;Sanaei & Cummings 2017), their direct applicability to optimization and design of real systems is questionable. On the other hand, laboratory experimentation of promising designs, and their consequent optimization, may be prohibitively expensive.…”

Section: Introductionmentioning

confidence: 99%

“…standard and complete blocking, cake filtration, etc. ), and its impact on system scale performance, quantified by, e.g., energy input and permeate flux (Griffith et al 2014(Griffith et al , 2016Sanaei & Cummings 2017). However, the fouling mechanism is generally not dynamically coupled to the local hydrodynamics, and their dynamic feedbacks on flux reduction is not accounted for.…”

Section: Introductionmentioning

confidence: 99%

Rough or wiggly? Membrane topology and morphology for fouling control

Ling

Battiato

2019

J. Fluid Mech.

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Reverse Osmosis Membrane (ROM) filtration systems are widely applied in wastewater recovery, seawater desalination, landfill water treatment, etc. During filtration, the system performance is dramatically affected by membrane fouling which causes a significant decrease in permeate flux as well as an increase in the energy input required to operate the system. Design and optimization of ROM filtration systems aim at reducing membrane fouling by studying the coupling between membrane structure, local flow field, local solute concentration and foulant adsorption patterns. Yet, current studies focus exclusively on oversimplified steady-state models that ignore any dynamic coupling between the fluid dynamics and the transport through the membrane, while membrane design still proceeds through trials and errors. In this work, we develop a model that couples the transient Navier-Stokes and the Advection-Diffusion-Equations, as well as an adsorptiondesorption equation for the foulant accumulation, and we validate it against unsteady measurements of permeate flux as well as steady-state spatial fouling patterns. Furthermore, we analytically show that, for a straight channel, a universal scaling relationship exists between the Sherwood and Bejam numbers, i.e. the dimensionless permeate flux through the membrane and the pressure drop along the channel, respectively. We then generalize this result to membranes subject to morphological and/or topological modifications, i.e., whose shape (wiggliness) or surface roughness is altered from the rectangular and flat reference case. We demonstrate that universal scaling behavior can be identified through the definition of a modified Reynolds number, Re , that accounts for the additional length scales introduced by the membrane modifications, and a membrane performance index, ξ, which represents an aggregate efficiency measure with respect to both clean permeate flux and energy input required to operate the system. Our numerical simulations demonstrate that 'wiggly' membranes outperforms 'rough' membranes for smaller values of Re , while the trend is reversed at higher Re . To the best of our knowledge, the proposed approach is the first able to quantitatively investigate, optimize and guide the design of both morphologically and topologically altered membranes under the same framework, while providing insights on the physical mechanisms controlling the overall system performance. † Email address for correspondence: ibattiat@stanford.edu arXiv:1809.00217v1 [physics.flu-dyn] 1 Sep 2018

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Flow and fouling in membrane filters: effects of membrane morphology

Cited by 39 publications

References 27 publications

Modeling and design optimization for pleated membrane filters

Modeling and design optimization for pleated membrane filters

Growth of clogs in parallel microchannels

Rough or wiggly? Membrane topology and morphology for fouling control

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