Influence of ionic strenght and pH of dispersed feeds on microfiltration

Abstract

The fluences of particle shape, -potencial and size with change of pH and ionic strenght on permeate flux during the microiltration o model dispersions (two different china clays with mean particle sizes 3.5 m and 1.5 um) on flat sheet ceramic membranes (ZrO2, mean size o pores 0.2 mm) have been studied. The experimental filtration system and the dispersion characterisation experiments are presented. The results of the experiments show that -potential of the particleshas considerable impact on the magnitude of the cake resistance and hence on the permeate flux. The effects are especially pronounced during the microfiltration of dispersion in the area close to isoelectric point of dispersion, where the dispersionhas tendency to instability and the particles tend to aggregate. The effects resulted in higher porosity filter cakes (deposits) and a lower value of filter cake resistance, and hence to a permeate flux that increased to double the value of a non-treated dispersion. These observations are caused the particle interactions.