Assessing some advanced oxidation processes in the abatement of phenol aqueous solutions

Abstract

In this work, phenol oxidation in aqueous solution promoted by the effect of the oxidizing agents H 2 O 2 , O 3 and UV radiation and their synergy in four different advanced oxidation processes (O 3 , O 3 /UV, H 2 O 2 /O 3 and O 3 /H 2 O 2 /UV) were assayed. Studies were performed with a closed-loop hydraulic circuit set up with a relatively high volume of solution (500 cm 3 ) during 90 min of treatment time. Parameters such as concentration for oxidizing species, pH, presence of UV irradiation were evaluated. The resulting degradation efficiencies were evaluated using GC-MS. The agents here used were se-lected considering their ease of handling and low toxicity, generation of deposited matter or sludge, so a filtration treatment for the analysis of the samples was not required. In all cases, it was observed that with increasing treatment time better degradation efficiencies were obtained. The best results were obtained with the combination of O 3 /H 2 O 2 /UV where up to 95% degradation was attained at pH 9, which is due to active species generated in the process, e.g., O 3 and OH  , on the contaminant. SPE was performed for determining the presence of several by-products, mainly: catechol, resorcinol and hy-droquinone, which were identified.