Effect of a previous coagulation stage on the ultrafiltration of a metalworking emulsion using ceramic membranes

The addition of a coagulant salt in the UF treatment of an o/w emulsion modifies in a great extent the physicochemical properties of the oil droplets and, therefore, the electrostatic interactions among them. As a result, phenomena such as coalescence, gel layer formation, permeate flux reduction, membrane fouling or oil retention are strongly affected.