Doxycycline Degradation by the Oxidative Fenton Process

Abstract

Doxycycline is a broad‐spectrum tetracycline occurring in domestic, industrial, and rural effluents, whose main drawback is the increasing emergence of resistant bacteria. This antibiotic could be degraded by the so‐called Fenton process, consisting in the oxidation of organic pollutants by oxygen peroxide (H 2 O 2 ) in the presence of Fe 2+ . Experiments were performed according to an experimental Rotational Central Composite Design to investigate the influence of temperature (0–40.0°C), H 2 O 2 concentration (100–900 mg/L), and Fe 2+ concentration (5–120 mg/L) on residual doxycycline and total organic carbon concentrations. Whereas the final residual doxycycline concentration ranged from 0 to 55.8 mg/L, the oxidation process proved unable to reduce the total organic carbon by more than 30%. The best operating conditions were concentrations of H 2 O 2 and Fe 2+ of 611 and 25 mg/L, respectively, and temperature of 35.0°C, but the analysis of variance revealed that only the first variable exerted a statistically significant effect on the residual doxycycline concentration. These results suggest possible application of this process in the treatment of doxycycline‐containing effluents and may be used as starting basis to treat tetracycline‐contaminated effluents.