The effects of physicochemical changes on critical flux of skimmed milk ultrafiltration
Wirote Yourvaong, Alistair Steven Grandison, and Michael John Lewis
pp. 929 - 939
Abstract
The effects of physical and physicochemical changes by modifying pH, increasing ionic strength and adding CaCl2 or citrate of skimmed milk on the critical flux and fouling reversibility during ultrafiltration were studied. The critical flux of skimmed milk was decreased as skimmed milk was modified by these methods. In general, decreases in critical flux were explained well by the surface charge of the particles such as whey proteins, casein micelles, and particle size distribution. The critical flux appeared to decrease as the surface charge of these proteins decreased. The results also indicated that small particles e.g. whey proteins and casein molecules played a major role in determination of critical flux. The fouling reversibility appeared to be dependent on physicochemical properties of skimmed milk. Fouling reversibility decreased (irreversible fouling increased) when lowering the pH, increasing ionic strength and adding CaCl2 and increased when increasing pH and adding citrate.