Activated carbon was prepared from Tuncbilek-Kutahya (Turkey) lignite by chemical activation with KOH (impregnation ratio 1:2). Pore characteristics of the activated carbon, such as BET surface area, pore volume, size distribution and the diameter of pores, were determined. BET surface area was found to be 902 m(2)/g, and other characteristic values are as follows: S-micro:560 m(2)/g V-total: 0.50 cm(3)/g, V-micro: 0.30 cm(3)/g and average pore diameter: 2.21 nm (4 V/A by BET). The prepared activated carbon was used to adsorb Rhodamine-B (RB) from aqueous solution in a batch reactor. The adsorption isotherm of process could be best identified using the Langmuir model since it gave a better fit and had a higher R-2 value (0.9908) than Freundlich model. The kinetics of the adsorption of RB was tested using a pseudo-second order equation and an intraparticle diffusion model. Adsorption capacity was determined to be between 1.80-2.55 10(-4) mol.g(-1). It was found that the boundary layer thickness increased as the temperature increased (50.641 - 64.271).