A combined network model for membrane fouling

Griffiths, I.M., Kumar, A. and Stewart, P.S. (2014) A combined network model for membrane fouling. Journal of Colloid and Interface Science, 432, pp. 10-18. (doi:10.1016/j.jcis.2014.06.021) (PMID:25042380)

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Publisher's URL: http://dx.doi.org/10.1016/j.jcis.2014.06.021

Abstract

Membrane fouling during particle filtration occurs through a variety of mechanisms, including internal pore clogging by contaminants, coverage of pore entrances, and deposition on the membrane surface. Each of these fouling mechanisms results in a decline in the observed flow rate over time, and the decrease in filtration efficiency can be characterized by a unique signature formed by plotting the volumetric flux, bQ , as a function of the total volume of fluid processed, bV . When membrane fouling takes place via any one of these mechanisms independently the bQ bV signature is always convex downwards for filtration under a constant transmembrane pressure. However, in many such filtration scenarios, the fouling mechanisms are inherently coupled and the resulting signature is more difficult to interpret. For instance, blocking of a pore entrance will be exacerbated by the internal clogging of a pore, while the deposition of a layer of contaminants is more likely once the pores have been covered by particulates. As a result, the experimentally observed bQ bV signature can vary dramatically from the canonical convex-downwards graph, revealing features that are not captured by existing continuum models. In a range of industrially relevant cases we observe a concave downwards bQ bV signature, indicative of a fouling rate that becomes more severe with time. We derive a network model for membrane fouling that accounts for the inter-relation between fouling mechanisms and demonstrate the impact on the bQ bV signature. Our formulation recovers the behaviour of existing models when the mechanisms are treated independently, but also elucidates the concave-downward bQ bV signature for multiple interactive fouling mechanisms. The resulting model enables post-experiment analysis to identify the dominant fouling modality at each stage, and is able to provide insight into selecting appropriate operating regimes.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stewart, Dr Peter
Authors: Griffiths, I.M., Kumar, A., and Stewart, P.S.
College/School:College of Science and Engineering > School of Mathematics and Statistics > Mathematics
Journal Name:Journal of Colloid and Interface Science
Publisher:Elsevier
ISSN:0021-9797
ISSN (Online):1095-7103
Copyright Holders:Copyright © 2014 Elsevier
First Published:First published in Journal of Colloid and Interface Science 432:10-18
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher.

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