The kinetics and mechanism of adsorption of two commercial dyes (BR22., AB25), phenol, and 3-chlorophenol from water on activated carbons were studied at 30 degrees C. The activated carbons were prepared from plum kernels, and the activation temperature and time tested were in the ranges 750-900 degrees C and 1-4 h, respectively. Three simplified kinetic models including a pseudo-first-order, a pseudo-second-order, and an intraparticle diffusion model were tested. It was shown that the adsorption of both phenols could be fitted to a pseudo-second-order rate law, and that of both dyes could be fitted to an intraparticle diffusion model. Kinetic parameters were calculated and correlated with the physical properties of the adsorbents.