Study of ultrafiltration behaviour of emulsified metalworking fluids

Ultrafiltration (UF) has been accepted as a versatile membrane separation process for water purification and wastewater treatment in recent years. In this paper the UF separation behaviour of oil-in-water emulsion used usually for metalworking fluids was studied. The effect was investigated of different polymeric membrane materials, oil concentration in feed, transmembrane pressure, feed temperature and other process parameters on the permeate flux, oil rejection and chemical oxygen demand in the permeate in a laboratory scale. The foulant on the membrane surface was analyzed and the recovery of fouled membrane permeability was studied as well. Finally an empirical model of membrane fouling was discussed and tested experimentally.