In this work, an activated carbon derived from date pits and stems (DPSAC) was prepared by physical activation under N2 and used as a support of cobalt transition metals, by wetness impregnation at different Co content and different calcination temperatures. The optimal operator conditions were 20 wt% cobalt impregnation ratio and 300°C calcination temperature. The grafted material was characterized by methods: thermo gravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform of infrared spectroscopy (FTIR). The activated carbon (DPSAC) and grafted activated carbon (Co/DPSAC) were realized on adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solution, it was found that the cobalt-grafted dates pits and stems activated carbon promoted the 2,4-D adsorption kinetics, The Langmuir and Freundlich isotherms models were applied for the adsorption results. The rate of adsorption of 2,4-D onto (DPSAC) and (Co/DPSAC) were estimated and described using a pseudo-second order model. © 2017, Oriental Scientific Publishing Company. All rights reserved.