Enhanced Oxidation of Phenol by Copper-catalyzed Fenton-like Reaction in the Presence of Bicarbonate

In this study, the copper-catalyzed Fenton-like reaction in the presence of bicarbonate (i.e., the Cu(II)/HCO3−/H2O2 system) was examined for the phenol degradation. The rate of phenol degradation by the copper-catalyzed Fenton-like reaction ([Cu(II)]0 = 0.1 mM, [H2O2]0 = 10 mM, pH = 10) was accelerated by 17-fold in the presence of 50 mM HCO3−. The rate of phenol degradation by the Cu(II)/HCO3−/H2O2 system increased with increasing doses of Cu(II) and HCO3−, but showed an optimal value for the H2O2 dose and pH at 5 mM and 10, respectively. The Cu(II)/HCO3−/H2O2 system was selective in degrading phenolic compounds; benzoic acid was resistant to degradation. Cu(III) species (likely complexed forms with carbonate) are believed to be the reactive oxidants responsible for the phenol degradation by the Cu(II)/HCO3−/H2O2 system. Meanwhile, aerating CO2 gas successfully accelerated the phenol degradation by the copper-catalyzed Fenton-like reaction, implying that CO2 aeration can be a practical option to supply bicarbonate when implementing the Cu(II)/HCO3−/H2O2 system.