Filtration of protein colloids by fibrous membranes: A mechanistic investigation using packed bed filtration approach

• BSA filtration by the fibrous membranes was simulated with column filtration.
• Microfiltration and column filtration yielded similar attachment efficiencies.
• Membrane fouling was the most severe at pH close to the isoelectric point of BSA.
• BSA–BSA interactions strongly affected its removal by microfiltration.

This research aimed to use packed bed filtration as a novel approach to investigate fibrous membrane filtration of aqueous particles, a novel environmental application of fibrous materials and a new frontier for engineering colloidal science. For this purpose, bovine serum albumin (BSA) was filtered through a pre-characterized glass bead column to determine attachment efficiencies (α) of BSA onto glass beads. Subsequently, BSA was filtered through a glass-fiber membrane possessing similar surface elemental compositions as the glass beads. By simulating the glass fiber membrane as a packing of spherical glass particles with a diameter equivalent to fiber diameter, α values pertinent to BSA-glass fiber attachment were calculated using the clean bed efficiency model. A side-by-side comparison of the α values show that membrane filtration exhibited greater α values than column filtration, the α values calculated for membrane filtration were always about 1.5 times of those determined under similar conditions in column filtration. However, α values for the two systems varied with solution chemistry in similar trends and the maximal α values for both systems were both found at the isoelectric point of BSA (pHIEP = 4.78). This finding implies that fibrous membrane filtration may be studied using classical packed bed filtration theories.

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