Physical cleaning by means of electric field in the ultrafiltration of a biological solution

In spite of the advantages in the filtration method at great scale, the process is limited by the following problems: polarization by concentration, fouling and decline of the permeated flux. In this work, a potentially good cleaning strategy to decrease the fouling during the ultrafiltration processes of bovine plasma is investigated. In order to achieve a continuous process of work with a minimum operation cost and maintenance space distributions of electric fields are used. The electric field influence was analyzed for different plasma concentrations. Electro ultrafiltration experiments were performed using laboratory crossflow filtration equipment, equipped with a tubular conductive membrane Carbosep® (formed by a layer of ZrO2–TiO2 over a carbon support), fitted to a coaxial electrode. The electric field is applied by means of an alternating current generator. The applied voltage is a half wave soft rectified current, which is rectified before the connection to the membrane. The plasma proteins above the isoelectric point are negatively charged so when the field is applied the particles are taken off the surface of the membrane and transported towards the current of the hydraulic flow, producing a fast increase of the permeated flux and higher rates of protein concentration than with conventional crossflow ultrafiltration. An equivalent electric circuit model adequately interpreted the experimental data of current generated during the membrane cleaning and it is associated with the permeate flux measured.