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Model for colloidal fouling of membranes



A proposed theoretical model describes colloids deposition on a membrane surface accounting for surface interactions. A mass-transfer equation links the deposition rate to hydrodynamic conditions (permeation and tangential flow through a boundary layer thickness, δ) and to physicochemical properties of the suspension (diffusion, D, and potential barrier between particles, VB). This equation predicts the existence of a critical flux, Jcrit, for ultrafiltration, reverse osmosis, or microfiltration of large-size colloids as:

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Some of the trends observed when processing protein solutions are explained by this model. Previous experimental data for various colloids or our data with a clay suspension in the presence of electrolytes are also compared to predictions of our model. It explains the “flux anomaly” for particle sizes between 10 nm and 1 μm.

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