This paper discusses the sorption of cellooligosaccharides to activated clay in concentrated sulfuric acid solution. Cellobiose was sorbed to the clay in 72% (w/w) sulfuric acid but not in water; the sorption of glucose was not observed in both solutions. Hydrolysate of filter paper cellulose after 72% sulfuric acid treatment was also sorbed to the clay, and the sorbed sugars were partly released by diluting the mixture. The sorbed sugars could also be recovered in the form of D-glucose after hot dilute acid treatment of the sugar-acid-clay suspension. (C) 2009 Elsevier Ltd. All rights reserved.