Influence of adsorbent particles on a dynamic protein membrane in cross flow filtration Original Research Article

In industry, when operations of separation, concentration, purification or sterilisation are necessary, membrane processes can be applied. In the food industry, a tangential process is used in many sectors (milk, gelatine, vinegar, juice, wine, etc.). Other fields are also concerned with these processes among which are the control of suspension concentration before evaporation or drying stages, recycling of fluids (used water), treatment of fluids for the recovery of particle products (pigments). This work is a study of tangential microfiltration of suspensions in protein solutions on the one hand and the solid/liquid adsorption phenomenon, on the other hand. A porous mineral membrane with a 0.2 μm diameter was used, and a protein solution (β-lacto globulin, 10 mg/l concentration) with an active coal suspension ofvariable concentration. The microfiltration ofpure products (ultrapure water, activated coal, protein) has led to a better understanding of the role of each component in the process of separation. The adsorption of proteins with an active coal powder was studied afterwards in a microfiltration loop in an agitated cell. Experiments of the influence of the hydrodynamic parameters (transmembrane pressures, tangential speed) and composition ofthe suspension and/or solution (concentration) were necessary to detennine the performances and the effectiveness of the operation. Globally, the results obtained show the importance of the ionic force in the fluid and the existence of strong interactions between membrane and solvent on the one hand, and membrane and protein on the other hand. The application of models for the formation of the filling phenomenon opposed to the transfer of material and isotherm adsorption are proposed. The conformity of the test results with classical law (tangential filtration) predictions confirm the validity of the models and the established experimental protocol.