Caffeine degradation using Fenton’s reagent (Fe(II)/H2O2) and the Fenton-like reagent (Fe(III)/H2O2) was investigated in deionized water at an initial concentration of 5.2 μmol L-1 (1000 μg L-1). These two different oxidation processes were compared and it was observed that efficient caffeine degradation (95%) was promoted by Fenton’s reagent at an Fe(II)/H2O2 molar ratio of 3:10 after 30 min. The effect of chloride, sulfate and carbonate ions on the decomposition of caffeine by Fenton’s reagent and the Fenton-like reagent has been investigated. Also, the chronic toxicity of the caffeine degradation products was evaluated on aquatic life after treatment of a solution initially containing caffeine by Fenton’s reagent using an Fe(II)/H2O2 ratio of 3:10. Only when Ceriodaphnia dubia was exposed to the concentration of 100% v/v of this solution obtained after the treatment of caffeine by Fenton’s reagent using an Fe(II)/H2O2 ratio of 3:10, chronic toxicity over the evaluated microcrustacean was observed.
caffeine degradation; Fenton’s reagent; Fenton-like reagent; inorganic ion effects; ecotoxicological evaluation