Elektrofiltration von Biopolymeren

摘要

A difference in pressure is generated between the two sides of a filter medium (1) so that the liquid (2) charged with biopolymers (3), for instance xanthan, that is fed through the inlet (5) goes through the filter medium (1), wherein the biopolymers (3) are retained by the filter medium (1). As opposed to crossflow filtration, the main direction of movement (4) of the liquid (2) is determined by the difference in transmembrane pressure. A cathode (7) is arranged under the filter membrane (1). A membrane serving as anode (8) is arranged on the opposite side of the process chamber (9). An electrical field is built up between the electrodes (7, 8). Due to the fact that the biopolymer components (3) carry a negative surface charge, a force moving in the direction of the anode (8), and, hence, against the main direction of movement (4) of the liquid (2), impinges upon said components in the electrical field (8), whereby the concentration of biopolymers is reduced in the surroundings of the filter medium (1) and filtration speed is increased. A surprising, additional effect is that the electrical field leads to reinforced coagulation tendency of the biopolymers (3) which further favors filtration by the formation of agglomerates.