Competitive Adsorption of Quaternary Metal Ions, Ni2+, Mn2+, Cr6+, and Cd2+, on Acid-Treated Activated Carbon

This paper examined the competitive removal of metal ions from quaternary aqueous solutions containing Ni2+, Mn2+, Cr6+, and Cd2+ using adsorption on both acid-modified unmodified activated carbon. Activated carbon (AC) was oxidized with nitric acid, in granular (AGC) powder (APC) forms, tested for an solution. Surface oxidation led to a reduction BET surface area HK pore width increase intensities hydroxyl carboxyl functional groups AGC APC compared carbon, AC, as indicated FTIR analyses. The capacity all four AC order Ni2+ > Cr6+ while it altered two carbons be Mn2+. Acid treatment resulted high selectivity over other available 100% efficiency, decreased Cd2+, Mn2+ AC. improvement is due its higher ionic potential smaller size, which results faster diffusion stronger acidic located at edges. Therefore, will repel hinder accessing pores. Modeling isotherms DKR better than Freundlich Langmuir ions. showed strong attraction by ion exchange surface, their apparent energy (E) values. found physical APC. had very weak types presence