Electro-catazone treatment of ozone-resistant drug ibuprofen: Interfacial reaction kinetics, influencing mechanisms, and degradation sites

Abstract

Electro-heterogeneous catalytic ozonation (E-catazone) is a promising advanced oxidation process using a unique TiO2 nanoflower (TiO2-NF)-coated porous Ti anode. This study investigated interfacial reaction kinetics and the influencing mechanism of E-catazone degrading ozone-resistant drug ibuprofen. An elementary reactions library of the E-catazone process was established. The kinetic rate of key interfacial reactions under different operation parameters was quantitatively resolved. It was found that parameters such as current, initial pH, O 3 concentration, and flowrate mainly affect & BULL;OH formation and ibuprofen removal via influencing three key interfacial reactions including anodic TiO2-NF surface hydroxylation, subsequent TiO2-NF -OH/O3 heterogeneous catalysis, and cathodic generation of H2O2. In addition, the degradation pathways and sites of ibuprofen were also predicted via theoretical chemistry calculation, showing that & BULL;OH attacked C(12), C(11), or C(6) atom of the benzene ring in the ibuprofen via a radical adduct formation pathway. The results of this study will guide the application of the E-catazone process in the efficient removal of ozone-resistant drugs.