The removal of Ni(II) using chitosan-coated bentonite (CHB) from aqueous solutions was investigated under dynamic conditions. The CHB adsorbent was characterized using BET and thermogravimetric analysis. The effect of various experimental parameters such as bed depth (1.3-4.3 cm), flow rate (0.2-0.6 mL min-1), and initial concentration (500-1500 mg L-1) on the service time of the CHB bed and shape of the breakthrough curve was examined. The breakthrough curves become steeper and the bed service time becomes shorter with decreasing bed depth, and increasing flow rate and initial concentration. At bed depth of 4.3 cm, flow rate of 0.2 mL min-1, and initial concentration of 500 mg L-1, the maximum uptake capacity at breakthrough and exhaustion of 15 and 17 mg g-1, respectively, as well as the highest total Ni(II) removal of about 88% was achieved. The bed depth service time model was utilized to predict breakthrough times at various flow rate and initial concentrations. A good agreement is observed between the theoretical and experimental values at time of breakthrough under low flow rates and low initial concentration. But a slight deviation could be seen between the predicted and experimental breakthrough times at higher flow rate and initial concentration.
