", and N,N-dimethylaminoethyl or N,N-diethylaminopropyl acrylates and methacrylates, and the respective quaternary salts thereof.Other gelling materials are also suitable as a solid absorbent material.Examples of such gels may be based on acrylamides, acrylates, acrylonitriles, diallylammonium chloride, dialkylammonium chloride, and other monomers." . . . . .