Investigating fouling at the pore-scale using a microfluidic membrane mimic filtration system

Debnath, Nandini; Kumar, Aloke; Thundat, Thomas; Sadrzadeh, Mohtada

doi:10.1038/s41598-019-47096-6

Cited by 29 publications

(23 citation statements)

References 53 publications

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“…The presented method of combined pore network simulation and macroscopic modeling is of specific interest in cases of changes of the pore network structure or changes of the liquid and gas distributions during dynamic invasion. It is a generic method that could also be applied for situations where pore and throat sizes vary over time, e.g., as a result of fouling effects or pore blocking resulting from contaminations in the liquid phase [25,[61][62][63]. In such situations, a recursive procedure of alternating simulations is proposed.…”

Section: Macroscopic Continuum Modelmentioning

confidence: 99%

Computational Optimization of Porous Structures for Electrochemical Processes

et al. 2020

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Porous structures are naturally involved in electrochemical processes. The specific architectures of the available porous materials, as well as their physical properties, crucially affect their applications, e.g., their use in fuel cells, batteries, or electrolysers. A key point is the correlation of transport properties (mass, heat, and charges) in the spatially—and in certain cases also temporally—distributed pore structure. In this paper, we use mathematical modeling to investigate the impact of the pore structure on the distribution of wetting and non-wetting phases in porous transport layers used in water electrolysis. We present and discuss the potential of pore network models and an upscaling strategy for the simulation of the saturation of the pore space with liquid and gas, as well as the computation of the relative permeabilities and oxygen dissolution and diffusion. It is studied how a change of structure, i.e., the spatial grading of the pore size distribution and porosity, change the transport properties. Several situations are investigated, including a vertical gradient ranging from small to large pore sizes and vice versa, as well as a dual-porosity network. The simulation results indicate that the specific porous structure has a significant impact on the spatial distribution of species and their respective relative permeabilities. In more detail, it is found that the continuous increase of pore sizes from the catalyst layer side towards the water inlet interface yields the best transport properties among the investigated pore networks. This outcome could be useful for the development of grading strategies, specifically for material optimization for improved transport kinetics in water electrolyser applications and for electrochemical processes in general.

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Section: Macroscopic Continuum Modelmentioning

confidence: 99%

Computational Optimization of Porous Structures for Electrochemical Processes

et al. 2020

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“…Colloidal fouling of pressure‐driven membranes by silica, clay minerals, aluminum, iron and manganese oxides is also likely to occur if these substances are not disposed of properly. Already, fouling of NF and RO membranes by different colloidal substances has been extensively investigated 6,7 and results have shown that rough and hydrophobic membranes are highly prone to fouling by small colloids such as silica and aluminum 6,8 . Similar to organic fouling, flux decline in colloidal fouling has also been ascribed to the combined effects of an increase in hydraulic resistance imparted by the cake layer and CECP effects.…”

Section: Introductionmentioning

confidence: 99%

Effect of multivalent cations on membrane‐foulant and foulant‐foulant interactions controlling fouling of nanofiltration membranes

Mahlangu

Mamba

Verliefde

2020

Polymers for Advanced Techs

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Insight was gained into the various factors influencing membrane fouling in the presence of different cations. Membrane‐foulant interaction energies were computed from contact angle measurements following the Lifshitz‐van der Waals/acid‐base approach. A unique approach was used to investigate cake‐enhanced concentration polarization (CECP) effects. Calcium worsened organic fouling through organic‐calcium complexation and increasing foulant affinity for the membrane surface, whereas magnesium and lanthanum had less influence on membrane fouling as they moderately decreased the foulants' affinity for the membrane surface. Fouling was facilitated by permeation drag and reduction in membrane‐foulant electrostatic repulsive interactions due to slight neutralization of foulant and membrane zeta potential. Although cake layers formed in the presence of magnesium and lanthanum had low resistance to water flow, the cake layers resulted in severe CECP effects. Initial membrane fouling rates related well to energies of adhesion, whereas later fouling rates did not show clear correlation to energies of cohesion.

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“…At higher applied pressure, organic or inorganic particles are forced to pass through the membrane structure. Thus, under this condition, it is anticipated that pore-blocking could occur which leads to a greater accumulation of bacteria and other foulants on the membrane surface 45 , 46 . Moreover, the bacterial attachment would also be greater as the normal shear stress (equivalent to static pressure 47 ) is increased, resulting in higher biofilm thickness, as evident in the OCT scans.…”

Section: Resultsmentioning

confidence: 99%

Novel hole-pillar spacer design for improved hydrodynamics and biofouling mitigation in membrane filtration

Qamar

Kerdi

Ali

et al. 2021

Sci Rep

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Feed spacers are the critical components of any spiral-wound filtration module, dictating the filtration performance. Three spacer designs, namely a non-woven commercial spacer (varying filament cross-section), a symmetric pillar spacer, and a novel hole-pillar spacer (constant filament diameter) were studied using Direct Numerical Simulations (DNS), 3-D printed and subsequently experimentally tested in a lab-scale ultrafiltration set-up with high biofouling potential feed water at various feed pressures. Independent of the applied pressure, the novel hole-pillar spacer showed initially the lowest feed channel pressure drop, the lowest shear stress, and the highest permeate flux compared to the commercial and pillar spacers. Furthermore, less biofilm thickness development on membrane surface was visualized by Optical Coherent Tomography (OCT) imaging for the proposed hole-pillar spacer. At higher feed pressure, a thicker biofilm developed on membrane surface for all spacer designs explaining the stronger decrease in permeate flux at high pressure. The findings systematically demonstrated the role of various spacer designs and applied pressure on the performance of pre-treatment process, while identifying specific shear stress distribution guidelines for engineering a new spacer design in different filtration techniques.

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Investigating fouling at the pore-scale using a microfluidic membrane mimic filtration system

Cited by 29 publications

References 53 publications

Computational Optimization of Porous Structures for Electrochemical Processes

Computational Optimization of Porous Structures for Electrochemical Processes

Effect of multivalent cations on membrane‐foulant and foulant‐foulant interactions controlling fouling of nanofiltration membranes

Novel hole-pillar spacer design for improved hydrodynamics and biofouling mitigation in membrane filtration

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