Development of an asymmetric ultrafiltration membrane based on phosphates industry sub-products

Abstract

New ultrafiltration membrane from phosphates industry sub-products material was prepared. The choice of this material is mostly due to its abundance in the Tunisian ores. However, it is considered as harmful subproduct for environment. Plastic paste was prepared using 250µm calibrated powder of mud of hydrocyclone laundries phosphates mixed with organic additives and water and then was shaped into a tube by extrusion molding. After drying and sintering at 900°C, the obtained support exhibits an average pore diameter and porosity of about 1.07μm and 39%, respectively. It shows also a very interesting properties in terms of mechanical and corrosion resistances.The coated layer resulting in the ultrafiltration (UF) membrane was performed by a slip-casting method using a suspension made of a mixture of the mud powder, water and polyvinyl alcohol solution (PVA), then heated at 650°C. The UF membrane average pore diameter measured by nitrogen adsorption/desorption method was of 11nm. The determination of the membrane water permeability shows a value of 90l/hm2bar which is suitable for membrane operating in UF domain.The application for the treatment of industrial textile wastewater shows an important decrease in turbidity (inferior to 1 NTU), chemical oxygen demand (COD) (retention rate of about 90%) and almost a total color removal.