Oxidative degradation of sulfathiazole by Fenton and photo-Fenton reactions

Abstract

This article presents experimental results on 47 μmol L(-1) sulfathiazole (STZ) degradation by Fenton and photo-Fenton reactions using multivariate analysis. The optimal experimental conditions for reactions were obtained by Response Surface Methodology (RSM). In the case of the Fenton reactions there were 192 μmol L(-1) ferrous ions (Fe(II)) and 1856 μmol L(-1) hydrogen peroxide (H2O2), as compared with 157 μmol L(-1) (Fe(II)) and 1219 μmol L(-1) (H2O2) for photo-Fenton reactions. Under these conditions, around 90% of STZ degradation were achieved after 8 minutes treatment by Fenton and photo-Fenton reactions, respectively. Moreover, a marked difference was observed in the total organic carbon (TOC) removal after 60-min treatment, achieving 30% and 75% for the Fenton and photo-Fenton reactions, respectively. Acetic, maleic, succinic and oxamic acids could be identified as main Fenton oxidation intermediates. A similar pattern was found in the case of photo-Fenton reaction, including the presence of oxalic acid and ammonia at short periods of irradiation with UV-A. The calculated values of Average Oxidation State (AOS) corroborate the formation of oxidized products from the initial steps of the reaction.

Elucidation of the degradation pathways of sulfonamide antibiotics in a dielectric barrier discharge plasma system

“…Velásquez et al [46] reported that the degradation of STZ would begin with the attack of hydroxyl radical to benzene ring, with the formation of 4-hydroxy-N-(1,3-thiazol)-benzenesulfonamide (A4), releasing NH 4 + . Subsequently, the ring opening of this compound A4 takes place, which produces a complex mixture of carboxylic and dicarboxylic acids.…”

Methodology of Drought Stress Research: Experimental Setup and Physiological Characterization

“…Due to the drought-related stomata closure and overload of electron-transport chains, the rate of this process is essentially increased [151]. The formed O 2 − can be dismutated to hydrogen peroxide (H 2 O 2 ), which can further yield highly toxic hydroxide radical (OH · ), for example, by the Fenton reaction in the presence of certain transition metal ions [152]. On the PS II donor side, incomplete water oxidation also leads to H 2 O 2 production.…”

Adsorptive Removal and Adsorption Kinetics of Fluoroquinolone by Nano-Hydroxyapatite

“…Various methods for the removal of antibiotics have been applied to purify water, such as conventional techniques (biological processes, filtration, coagulation/flocculation and sedimentation) [ 17 – 21 ], advanced oxidation processes (AOPs) [ 22 ], adsorption [ 23 ], membrane processes [ 24 ], ozonation [ 25 , 26 ], photochemical degradation [ 1 , 27 ], and Fenton/photo-Fenton processes [ 28 ]. Among the above water-treatment techniques described, adsorption is generally preferred for the removal of FQs due to its relevant characteristics of high efficiency, easy handling, availability of different adsorbents, and cost effectiveness [ 29 ].…”