Effects of Inorganic Anions on Methylene Blue Degradation by Heterogeneous Fenton-Like Reaction using Cobalt Dopped Carbon Aerogel Catalyst

Abstract

In this study, novel cobalt-doped carbon aerogels (Co-CA) are synthesized from jackfruit core via sequential steps of hydrothermal, impregnation, and pyrolysis. The aerogels show a uniform distribution of cobalt particles on the aerogel surface without any bunching regions. The large surface area of 160 m²/g and pore diameter of 10.5 nm are determined for the Co-CA by the Brunauer-Emmett-Teller equation and Barrett-Joyner-Halenda model. The as-fabricated Co-CA exhibit an excellent methylene blue (MB) degradation efficiency via a heterogeneous Fenton-like reaction in the presence of H₂O₂ and carbonate ions. While chloride (Cl^-) and sulfate (SO₄^2-) ions show insignificant changes in the MB degradation efficiency, the presence of carbonate (CO₃^2-) and phosphate (PO₄^3-) ions causes a great impact on the MB removal efficiency with the highest value of up to 90% when CO₃^2- concentration is considerably low at 1 mM. Compared with the condition of only H₂O₂ in the environment, the addition of CO₃^2- extensively increases the rate of MB degradation by recording the time of reaching the equilibrium state in only 15 min. The dye treatment efficiency is improved over the control condition (no inorganic anions) only when the CO₃^2- concentration is low. At the anion concentrations of 10 mM or more, the MB degradation by Co-CA is hindered since the treatment efficiency is reduced. This study successfully develops functional Co-CA owning remarkable MB removal efficiency, indicating their great potential in dye-polluted wastewater management.