Evaluation of adsorption efficiency of activated carbon/chitosan composite for removal of Cr (VI) and Cd (II) from single and bisolute dilute solution

The aim of this study was to evaluate the adsorption capacity of a novel activated carbon coated with chitosan for the removal of Cr (VI) and Cd (II) ions from single and bi-solute dilute aqueous solutions. In addition, the adsorption abilities of activated carbon (AC), chitosan (CH) and chitosan / activated carbon composite (CHAC) were compared. The adsorption studies were performed in a batch system, and the effects of various operating parameters such as solution pH, particle size and the dose of adsorbent were considered for the removal of Cr (VI) and Cd (II) via the Taguchi method. The equilibrium experimental data were well fitted to the Langmuir isotherm for single and bi-solute solutions. The adsorption capacities of the AC and CH adsorbents were improved by means of the synthesized CHAC composite. As expected, the competitive adsorption of metal ions on the CHAC surface led to a reduction in the adsorption capacity from 90.9 mg/g to 41.94 mg/g for Cr (VI) ions and 52.63 mg/g to 30.21 mg/g for Cd (II) ions, respectively. The adsorption potential of CHAC for Cr (VI) was greater than Cd (II) for the different metal solution–adsorbent systems. The kinetic studies indicated that the adsorption process was best described by pseudo-second-order kinetics for single and bi-solute solutions.