Optimization and Kinetics of Nickel Ion Adsorption from Electroplating Effluent onto Activated Carbon Prepared from Egg Shell

Abstract

This study was aimed at investigating the kinetic modelling of the treatment of nickel(II) ions in electroplating effluent by an activated carbon prepared from Anas platyrhyncha egg shell. The following process variables were chosen for optimizing the batch operation: Ni(II) ion conc. in effluent (10–50 mg/ℓ), pH (4–8), adsorbent dosage (0.3–0.9 g), temperature (30–70 °C). A five-level, four-variable central composite design was used to evaluate the effects of these parameters on the adsorption of Ni(II) ions onto Anas platyrhyncha egg shell. The optimization process demonstrated significant interaction between the process variables studied. Adsorption kinetic data were tested using the pseudo-first-order, pseudo-second-order and intra-particle diffusion models. Kinetic studies revealed that the adsorption process was best described by the pseudo-second-order reaction model. Reichenberg plots were used to calculate the rate-controlling parameters and the effective diffusion coefficient. Adsorption occurs via particle diffusion at low concentrations, while film diffusion becomes the rate-determining step at higher concentrations.