Investigation of the Roles of Various Radicals in the Degradation of Tetracycline in the Fenton System

Abstract

There is an urgent need to address the significant harm caused to aquatic environments by the widespread use of tetracycline (TC). The Fenton process has been shown to effectively remove organic pollutants from water, utilizing various oxidizing agents such as H₂O₂, •O₂⁻, HO₂• and •OH. However, the specific roles of these active species in breaking the bonds of TC molecules during degradation and mineralization remain unclear. This study employs experimental methods to assess TC concentration and chemical oxygen demand (COD) as key indicators, while also analyzing total organic carbon (TOC). It investigates the contributions of each active substance within the Fenton system and identifies the key species responsible for TC degradation, aiming to improve the system's effectiveness against TC contamination. Experimental results indicate that neither H₂O₂ nor •O₂⁻ effectively degrades TC; in contrast, both HO₂• and •OH significantly disrupt TC bonds, leading to the formation of smaller organic compounds. Notably, •OH plays a crucial role in further mineralizing pollutants and reducing COD levels in solution. By analyzing the contribution rates and mechanisms of these active substances, we conclude that •OH is the primary agent for TC oxidation in the Fenton system. Therefore, maximizing the production of •OH while minimizing its ineffective consumption may be an effective strategy for enhancing TC degradation efficiency within this framework.