Nickel removal from aqueous solutions by alginate-based composite beads: Central composite design and artificial neural network modeling

Alginate-based composite bead (AB) was applied for the removal of Ni(II) ions from solutions in batch and fixed-bed systems. The reuse feasibility of the spent adsorbent was investigated for binding azo dye. Elovich kinetic model and mean adsorption energy (E) (13.2 kJ mol−1) indicated that Ni(II) ions removal followed ion-exchange mechanism. 98.5% removal for Ni(II) was observed at the maximum column operation (viz. 2.0 mL/min flow rate, 100.0 mg/L influent concentration and 9.0 g dose). Artificial neural network (ANN) and central composite design (CCD) models were applied to elucidate the complex adsorption process, and the finding is consistent with the experimental data. Desorption efficiency (DE) was noted to be higher when HCl (DE = 92%) was used as desorbing agent compared to NaOH (DE = 6%) in the first cycle.