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

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 (HO) 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 HO presence. Three solutions were tested: i) 20 mg/L of TC; ii) 20 mg/L of TC with 2 % (v/v) HO 35 %; and iii) 20 mg/L of TC with 0.8 % (v/v) HO 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 HO and the optimization of operational parameters significantly enhanced TC mineralization. The highest mineralization (80.1 %) was achieved with 0.8 % HO at an ozone dosage of 5.85 g/L. Conversely, the addition of 2 % HO 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 HO 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.