Sorption efficiency of Cr(VI) on used black tea leaves from aqueous solutions was evaluated. Kinetic studies were conducted using a batch process, and the effects of Cr(VI) concentration, solution pH and temperature on the adsorption and reduction performance were investigated. The adsorption kinetics follows pseudo-second order rate equation better than pseudo-first order one. The rate constant of pseudo-second order adsorption decreases with increasing an initial concentration of Cr(VI), up to a certain limit, then becomes steady. The maximum value of the rate constant was observed at an initial solution pH = 1.3. The rate constant was found to linearly increase with an increase in temperature, showing that the process is endothermic. The activation energy of adsorption calculated from Arrhenius plot is 16.3 kJ/mol, indicating that the adsorption occurred easily. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]