Polymer membranes for active degradation of complex fouling mixtures

Abstract Immobilization of different digestive enzymes consisting of proteases, amylases and lipases on polyvinylidene fluoride resulted in biocatalytic active polymer membranes with self-cleaning capability. Activation of enzymes and therefore “switching on” the membrane system was achieved by adjusting pH and temperature leading to an active degradation of fouled substances on its surface. Fouling and self-cleaning experiments with solutions of protein, lipid, carbohydrate, and a mixture were performed and resulted in high recovery of water permeance (99%, 72%, 77%, and 68%, respectively). Furthermore, real samples including river water (75% after first cycle), and household sewage (62%) were examined, as well as first investigations in longtime performance, and stability were performed. Comprehensive membrane characterization was conducted by investigation of the immobilized enzyme concentration, enzyme activity, fouling tests and water permeation monitoring, mercury porosimetry, X-ray photoelectron spectroscopy, scanning electron microscopy, and finally, zeta potential, as well as water contact angle measurements.