Enhanced photo-Fenton process for tetracycline degradation using efficient hydrogen peroxide dosage

The remediation of water solutions containing tetracycline antibiotic (TC) using photo-Fenton treatments has received scarce attention in the literature. However TC deserves attention due to its condition of emerging contaminant. In this work, TC oxidation in water solutions (12 L, 40 mg L−1) by means of photo-Fenton reaction under variable hydrogen peroxide dosage is investigated. This shows a more efficient use of the hydroxyl radicals produced in the reaction medium and enhances treatment performance. First, a suitable range of Fenton reagent loads is determined in a preliminary study. The hydrogen peroxide dosage is parameterized through two variables: the initial release of the total load, y0 (kick-off), and the time tini at which the continuous dosage of the rest of the load starts. Hence, a design of experiments (22) can be used to characterize the performance of the process under different hydrogen peroxide dosage protocols. The results obtained this way show that total TC remediation is attained in all the cases studied, but alike amounts of hydrogen peroxide lead to total mineralization only when the dosage scheme is conveniently tuned. Therefore, the photo-Fenton treatment has proved to be effective in removing TC from water solutions, and the opportunity for an efficient dosage to reduce the requirements of hydrogen peroxide has also been confirmed.