Effect of ageing on the microfiltration performance of ceramic membranes

The present work considers the influence of time or ageing on the electrokinetic characteristics of ceramic microfiltration and their subsequent impact on the microfiltration performances of whey suspensions. The filtration performance is assessed both in terms of permeate flux and total organic carbon (TOC). As the ageing period increases, the zeta potential of the membrane increases and plateaus towards the end of the ageing period. Higher permeate fluxes are found over the ageing period. The effect of ageing seems to have the greatest influence on the zeta potential and fluxes at the alkaline pH compared to the acidic pH and at the pH corresponding to the isoelectric point. Highest TOC removals were found at alkaline conditions. The main consequences of these results concern the interactions between membrane and whey particles. Despite the fact that the surface charge only depends on the pH, the various surface states of alumina may induce different strengths of electrostatic interactions or hydrophobic interactions between membrane and particles.

► Ageing changes the electrokinetic surface properties of membranes.
► Higher membrane zeta potentials found at longer ageing periods.
► Improved fluxes and retentions found in aged membrane.
► Electrostatic interactions predominates the membrane-particle interactions.
► First study to report the effects of ageing on filtration performances.