Degradation of sulphamethazine by means of an improved photo-Fenton process involving a hydrogen peroxide systematic dosage

Abstract

Despite being acknowledged as an emerging contaminant, sulphamethazine (SMT) degradation has received scarce attention in the advanced oxidation processes field. Thus, this work addresses the degradation of SMT in water solutions (12 L of 25 mg L⁻¹ samples) by means of a photo-Fenton process and a systematic H₂O₂ dosage protocol that enhances its performance. A conventional photo-Fenton process led to 86% mineralization after 120 min treatment when adding the Fenton reactants at once (initial concentrations were 10 mg L⁻¹ Fe(II) and 200 mg L⁻¹ H₂O₂). Conversely, the process achieved the total mineralization of the samples in less than 75 min when the same amount of H₂O₂ was continuously dosed according to a conveniently tuned dosage protocol. In both cases, total SMT degradation was achieved within 10 min. Hence, this work's aim is to determine the efficient dosage conditions of H₂O₂. The results show that a significant improvement of the photo-Fenton mineralization of SMT solutions is possible by adjusting the dosage of H₂O₂.

Keywords:

• sulphamethazine
• emerging contaminants
• photo-Fenton process
• hydrogen peroxide dosage