Degradation of 2-hydroxybenzoic acid by advanced oxidation processes

AUTOR(ES)
FONTE

Brazilian Journal of Chemical Engineering

DATA DE PUBLICAÇÃO

2009-09

RESUMO

In this study, advanced oxidation processes (AOPs) such as the UV/H2O2 and Fenton processes were investigated for the degradation of 2-hydroxybenzoic acid (2-HBA) in lab-scale experiments. Different [H2O2]/[2-HBA] molar ratios and pH values were used in order to establish the most favorable experimental conditions for the Fenton process. For comparison purposes, degradation of 2-HBA was carried out by the UV/H2O2 process under Fenton experimental conditions. The study showed that the Fenton process (a mixture of hydrogen peroxide and Fe2+ ion) was the most effective under acidic conditions, leading to the highest rate of 2-hydroxybenzoic acid degradation in a very short time interval. This same process led to a six-fold acceleration of the oxidation rate compared with the UV/H2O2 process. The degradation of 2-hydroxybenzoic acid was found to follow first-order kinetics and to be influenced by the type of process and the experimental conditions. The experimental results showed that the most favorable conditions for 2-HBA degradation by the Fenton process are pH around 4-5, [Fe2+] = 0.6 mmol.L-1, and [H2O2]/[2-HBA] molar ratio = 7. The hydroxylation route is explained here for the two processes, and the results are discussed in the light of literature information.

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