Fixed-bed column studies on the removal of copper using chitosan immobilized on bentonite

The use of chitosan immobilized on bentonite (CHB) in the removal of Cu(II) from aqueous solutions was investigated using a column system. The effect on the time of breakthrough and uptake capacity of the column was examined. The dynamics of the adsorption process were evaluated by using bed depth service time (BDST) model and Thomas model. The adsorption capacity of 14.92 mg Cu(II)/g CHB with 24 h breakthrough was achieved at 500 mg/L of initial concentration, bed height of 4.3 cm, and flow rate of 0.20 mL/min. The time of breakthrough decreases while breakthrough curves become sharper with increase in flow rate and influent concentration, and a decrease in bed height of the adsorbent. Moreover, Thomas model was an acceptable kinetic model. The BDST model was utilized to compute dynamic bed capacity (N0), adsorption rate constant (kads), and critical bed depth (Z0) at 29.94 g/L, 0.000857 L/(mg h) and 0.9187 cm respectively.