The removal efficiency of Ni (II) ions from aqueous solution using regenerated cellulose was studied. The effects of solution pH, time, initial metal concentration and adsorbent dosage on metal adsorption efficiency were investigated. Response surface methodology (RSM) was applied to predict the behavior of the system. Based on the developed model, pH was found to be the main factor which had the highest influence on Ni (II) removal efficiency. It was observed that an increase in the pH from 3.75 to 7.25 resulted in a 51.6% increase in Ni (II) removal efficiency. Additionally, the time and adsorbent dosage were found to have positive influence on metal removal efficiency while Ni (II) removal efficiency reduced with initial metal concentration. The optimization of the integral main factors was performed. The suggested optimum values for pH, time, initial metal concentration, adsorbent dosage and Ni (II) removal efficiency were 6.4, 175.27 min, 32.5 ppm, 0.4 g and 98%, respectively.
