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

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 ($-lacto globulin, 10 mg/l concentration) with an active coal suspension of variable concentration. The microfiltration of pure 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 of the suspension and/or solution (concentration) were necessary to determine 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.

The study of the filtration of the suspension of an active coal showed that the essential cause of the fall of flow in the course of time is the instantaneous installation of filling (cake). The In the future, it would be interesting to test other adsorbents/protein model couples in order to generalize the validity of the models applied.