Thermal stimuli controlled functional filter cloth for liquid filtration

Advanced filtration media for process and wastewater purifn. have been developed. PET and PVA filter cloths coated with poly(N-isopropylacrylamide) (pNIPA) and its copolymers create a functional filter controlled by thermal stimuli. The concept is based on the filtration operation where the coating is an extended phase, and during the washing operation the coating is contracted allowing a fast and effective defouling. Coated fabrics are tested by synthetic and real white water solns. and by a protein soln. demonstrating applications in the pulp and paper and in the food industries. Fast and effective washing phenomena were obsd. Common washing chems. are acid or caustic and therefore the chem. stability of coatings was tested in various pH conditions. Results showed good stability as measured by flux behavior after aggressive long term chem. stressing. The demonstrated thermal response functional media offer a concept to develop a new filtration technol. with fast defouling and thus increased capacity in filtration units. Potential applications are, for example, clarification/cake filters where fouling is a key issue.