Abstract: A derivatized polysaccharide in which at least a portion of the active hydrogens originally present in the polysaccharide are substituted by monovalent aliphatic groups containing at least two carboxylic acid groups to an extent sufficient to provide a degree of substitution of at least about 0.1. The monovalent aliphatic groups contain from 4 to about 10 carbon atoms. The polysaccharide may be cellulose. At least a portion of the carboxylic acid groups present in the derivatized polysaccharide may be crosslinked permanently or reversibly. The monovalent aliphatic groups containing at least two carboxylic acid groups may be derived from 2,3-epoxysuccinic acid; 1,2-epoxypropane-1,2,3-tricarboxylic acid; 2-(epoxyethyl)-succinic acid; or mixtures thereof. Also provided is a method of preparing a derivatized polysaccharide.

Abstract: An adsorbent filter for removing caffeine from liquids. The filter is composed of a liquid permeable matrix of fibrous material having individual exposed surfaces; and a distribution of adsorbent clay minerals attached to individual exposed surfaces of the fibrous material by substantially non-transient bonding, so that passage of a liquid having a caffeine concentration ranging from about 20 to about 100 mg per 100 mL of liquid through the matrix for a contact time of less than about 2 minutes results in at least a 40 percent reduction in the caffeine concentration of the liquid. The matrix of fibrous material may be selected from woven fabrics, knit fabrics and nonwoven fabrics. The adsorbent clay minerals include, for example, sodium bentonite clays, calcium bentonite clays, acidified bentonite clays, and modified bentonite clays containing a flocculating agent.