The aim of the present study was to produce a high capacity and steady adsorbent able to separate uranium ions resulting from the nuclear fuel cycle process at different pHs and concentrations. AC/PAN (active carbon/polyacrylonitrile) composite adsorbent was investigated in a batch system for uranium sorption as a function of pH, contact time, initial metal ion concentration, temperature and adsorbent concentration. The adsorption mechanism was described through a comparison of linear and nonlinear regression analysis. The adsorption capacity was found to be 27.47 and 28.45 mg g(-1) according to the linear and non-linear regression analysis of the Langmuir isotherm, respectively. The adsorption mechanism followed to pseudo-second-order kinetics. The thermodynamic parameters (standard enthalpy (Delta H degrees = -23.46 kJ mol(-1)), entropy (Delta S degrees = 0.02 J mol(-1) K-1), and free energy (Delta G degrees)) were determined and the results indicated that the adsorption system was exothermic, spontaneous and favorable.