Sulfamethoxazole and Trimethoprim Degradation by Fenton and Fenton-Like Processes

Antover Panazzolo Sarmento,Antonio Teixeira De Matos,Alisson Carraro Borges,Lincoln Lucílio Romualdo

doi:10.3390/w12061655

Antover Panazzolo Sarmento, Antonio Teixeira De Matos + Show 2 more

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https://doi.org/10.3390/w12061655

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Abstract

In this work, the degradation of sulfamethoxazole (SMX) and trimethoprim (TMP) via Fenton and Fenton-like processes was evaluated using Mn2+ as supporting catalyst in the Fenton reaction. The optimum conditions of degradation were also evaluated. Besides that, the effect of independent factors pH, [H2O2], [Fe2+], [Mn2+] and reaction time (t) on the efficiency of the SMX and TMP degradation were assessed. Box–Behnken was the experimental design adopted, delineating the relative concentration (C/Co) of antibiotics after treatments as response variable. The inferences were conducted using variance analysis, Pareto chart, response surface methodology, and desirability function. Due to the lack of adjustment of the SMX degradation model, there are no more inferences about it. The significant variables (p ≤ 0.05) on TMP degradation were: reaction time quadratic and linear effect, [Fe2+] linear effect, [Mn2+] linear effect, interaction pH vs. [Mn2+]. The Mn2+ addition aided TMP degradation in environments with lower pH values. However, the addition may harm the efficiency of the antibiotic degradation at higher pH. The optimum condition for TMP degradation in the conventional process (without the addition of Mn2+) is: pH 5, [H2O2] equal to 4.41 mmol L−1, [Fe2+] equal to 0.81 mmol L−1 and 90 min reaction time.

Highlights

Advances of technology and scientific knowledge aim at the improvement of life quality for people
The analyses were conducted with high-performance liquid chromatography (HPLC) equipment from Shimadzu brand
Run—corresponds to the experiment number; pH, [H2 O2 ], [Fe2+ ], [Mn2+ ], e t—are the values that were used for each experiment for each variable as explained in Table 1; Efficiency—is the value in percentage of the degradation efficiency for each experiment; C/C0 —is the relative concentration after degradation of each experiment

Summary

Introduction

Advances of technology and scientific knowledge aim at the improvement of life quality for people. A relevant matter to be raised in relation to the excessive use of antibiotics is environmental contamination. After their ingestion by human beings, the natural elimination of part of the quantity that has been administered occurs, releasing in sewages high contaminant loads of antibiotics, with consequent contamination of water courses, fauna. Some researches, conducted in many countries in the world, have reported the detection in the aquatic environment of more than 80 emergent pollutants, such as medicines, products of veterinary use, hygiene products, agrichemicals, and endocrine disruptors, from synthetic or natural origin, and even some uncommon microorganisms in the studied regions [6,7,8,9]

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