Activated carbons have been prepared from sewage sludge of the municipal wastewater treatment plant using chemical activation method. Porous structure of activated carbon was characterized by nitrogen adsorption and scanning electron microscopy. And activated carbon was also characterized by its surface area and porosity. Then it was used as an adsorbent for the removal of nickel ions from aqueous solution. The effects of parameters such as contact time and initial nickel ion concentration were investigated. The adsorption kinetics of nickel ions in aqueous solution onto activated carbon was investigated through experimental data. The results showed that the adsorption processes were perfectly fitted to the pseudo-second order model with very high regression coefficients. It may be evaluated as an environmentally friendly and extra economic treatment of nickel ions in aqueous solution.