The natural biopolymer cellulose was initially chlorinated at the 6 carbon with a degree of substitution (DS) 0.99 +/- 0.01 and then reacted with aminoethanethiol to form a modified compound with different basic centers, and this material was characterized by elemental analysis, XRD, TG, FTIR and C-13 NMR. The matrix obtained was effective in removing red reactive anionic dye in an aqueous medium at pH values of 2 and 9. The equilibrium time of adsorption obtained was approximately 100 min (pH 2) and 160 min (pH 9), and the kinetics for both systems followed a pseudo-second-order model. The adsorption isotherms at different pH levels at three different temperatures obeyed the Langmuir model, and the maximum adsorption capacities were 78 mg g(-1) (pH 2) and 26 mg g(-1) (pH 9), and the interaction was electrostatic and hydrogen bonds and/or covalent, respectively. (C) 2012 Elsevier B.V. All rights reserved.