Advanced oxidation of tetracycline: Synergistic ozonation and hydrogen peroxide for sustainable water treatment

Abstract

Antibiotics, particularly tetracycline (TC), are a growing environmental concern due to their persistence in water and soil, which challenges traditional treatment methods. This study explores the combination of ozone (O₃) and hydrogen peroxide (H₂O₂) as an advanced oxidation process (AOP) for enhancing TC degradation and mineralization while minimizing byproduct formation. The optimization of ozonation was achieved by evaluating parameters such as pH, contact time, ozone flow rate, and H₂O₂ presence. Three solutions were tested: i) 20 mg/L of TC; ii) 20 mg/L of TC with 2 % (v/v) H₂O₂ 35 %; and iii) 20 mg/L of TC with 0.8 % (v/v) H₂O₂ 35 %. In-silico toxicity assessments and life cycle analysis (LCA) were also conducted to assess the ecotoxicity and environmental impact of the process. The results indicated that the addition of H₂O₂ and the optimization of operational parameters significantly enhanced TC mineralization. The highest mineralization (80.1 %) was achieved with 0.8 % H₂O₂ at an ozone dosage of 5.85 g/L. Conversely, the addition of 2 % H₂O₂ resulted in a mineralization of approximately 33.9–34.1 %, even with a 33.2 % reduction in ozone dosage (from 5.85 g/L to 3.91 g/L) due to a decrease in solution pH. The toxicity assessment of TC revealed significant risks to aquatic life, underscoring the need for environmental monitoring. LCA revealed that electricity consumption is the major environmental impact of the ozonation process. These findings highlight H₂O₂ as an effective and cost-efficient catalyst in ozonation systems for TC mineralization and emphasizes the importance of understanding reaction mechanisms to optimize the process.