Incorporation of the cake pressure profiles in the calculation of the effect of particle charge on the permeability of filter cakes obtained in the filtration of colloids and particulates

It was previously demonstrated [McDonogh et al., J. Membrane Sci., 21 (1984) 285-294] that electrokinetic interactions of charged particles could explain the particle charge dependent permeability of filter cakes. The original treatment to estimate the filter cake permeability has been extended to consider the pressure profile that develops through the filter cake. New experiments with polystyrene colloids show these effects are still very significant for particles as large as 0.1 μm in radius. The extended theoretical development, including estimates of both the electrokinetic interactions of the charged particles and the local compressive drag pressure within a filter cake, gives good agreement between experiment and theory over an order of magnitude of particle size, without invoking any non-experimental parameters.