Abstract: The sorption of cobalt to cellulose was studied by batch technique as a function of various environmental parameters such as ionic strength, pH, contact time, and temperature. The results indicate that the sorption of Co(Ⅱ) on cellulose is strongly dependent on pH and ionic strength. The sorption of Co(Ⅱ) is dominated by outer-sphere surface comple-xation and ion exchange at low pH, whereas inner-sphere surface complexation or surface precipitation is the main sorption mechanism at high pH values. The Langmuir and Freundlich models were used to simulate the sorption isotherms at three different temperatures of 283.15, 303.15 and 323.15K. The thermodynamic parameters (ΔH^θ, ΔS^θ and ΔG^θ) calculated from the temperature dependent sorption isotherms indicate that the sorption process of Co(Ⅱ) on cellulose is spontaneous and endothermic.