AOP as a degradative tool for oxidation of 4-hydroxybenzoic acid

Iron catalyzed hydrogen peroxide is a broad-spectrumoxidant that can rapidly destroy a variety of refractory organic compounds. The effectiveness of this process is credited to the formation of hydroxyl radicals (•OH) by the photolytic breakdown of H2O2. In this study, lab-scale experiments were conducted using UV/H2O2 and Fenton processes for the degradation of 4-hydroxybenzoic acid. Optimization of various parameters was carried out with different concentrations of H2O2 and pH values. Highest degradation under acidic conditions of 4-HBA at reasonably short time interval was observed in solar process. The experimental results showed that the most favorable conditions for 4-HBA degradation by the various process are pH around 3.5, [fe2+]=0.125 mmoles /l (7 ppm), and [Fe3+]=0.075mmoles/l (4 ppm) and H2O2]/[COD]=6.4.