Sustainable removal of copper from wastewater using chemically treated bio-sorbent: Characterization, mechanism and process kinetics

Abstract

This study introduces the impact of treating chicken drumstick bones on the removal of copper ions from an aqueous solution. An untreated bio-sorbent (UTB), base treated bio-sorbent (BTB), acid-treated bio-sorbent (ATB), and detergent treated bio-sorbent (DTB) chicken bones were assessed as potential Cu (II) bio-sorbents (Bio-S). The treatment efficiency was judged on the Cu (II) percentage removal efficiency (%Removal) and the adsorption capacity (qm). The Bio-S were characterized using FTIR and SEM. The changes exhibited in the surface functional groups corresponded to the improvement in %Removal and qm. Isotherms (including, Langmuir, Freundlich and Dubinin–Radushkevich [D–R]) and kinetic models (including pseudo-first-order kinetics, pseudo-second-order kinetics, the Elovich equation, and the intra-particle diffusion model) were used to model and predict the adsorption process. The results indicated that the DTB achieved %Removal of 100% and a qm of 28 mg g−1 in comparison to 73% and 19 mg g−1 for the UTB. The BTB demonstrated comparable results to the DTB with a qm of 25 mg g−1 and % Removal of 100%. However, the ATB exhibited a significantly lower qm of 8 mg g−1 and %Removal of 5%. The pseudo-second-order model provided the best representation of the adsorption kinetic data. This suggests that the sorbent is connected to the adsorbent by two or more steps, including intra-particle diffusion. The characterization tests indicated that the BTB and DTB underwent changes in the surface functional groups, increased the surface porosity, and enhanced the %Removal of Cu (II). The significant removal efficiency of the DBT has shown some promising results as a sustainable bio-sorbent for the removal of heavy metals (HMs) from aqueous solutions.