In the last years more and more attention has been paid to the surface chemistry of the active carbons selected for the adsorption of ions from solution [1]. The purpose of this work was to study the adsorption of nitrite ions from solutions on CAN-7 active carbon. The sample CAN-7 is a mesoporous active carbon with acidic surface due to method of obtaining (chemical activation with phosphoric acid) [2]. The presence of acidic functional groups on the active carbon surface has been evaluated by Boehm and potentiometric titration method, TPD-MS and FTIR spectroscopy [3]. For the description of the nitrite ions adsorption process on CAN-7 active carbon the influence of various experimental parameters (pH value, amount of adsorbent, initial concentration, and contacting time) was evaluated in batch experiments, at the ratio: liquid solid of 1: 500, the fraction of activated carbon was between 0.8 ÷ 2.0 mm. Adsorption equilibrium data were fitted to Langmuir, Freundlich and DubininRadushkevich isotherms and to different kinetic models (pseudo-first and pseudo-second kinetic models and intraparticle diffusion). The equilibrium adsorption data were best represented by the Langmuir isotherm. This means that the adsorption process is dominated by chemosorption on the energetic homogeneous surface. The correlation coefficients of the pseudo-second kinetic model have values close to one, and the calculated values of adsorption are very close to the values found experimentally. This suggests that the rate-determining step in these adsorption processes may be chemosorption. In the case of the intraparticle diffusion model, it is observed that the dependence is multilinear, indicating that the process has three stages. The slopes of the linear portions indicate the speed of the adsorption process. Thus, the diffusion speed decreases with the contact time due to the fact that the pores become smaller. The first linear region is probably due to adsorption in the activated carbon mesopores, while the second linear section represents, most likely, the transition from mesopores to micropores.