Electro-catazone treatment of an ozone-resistant drug: Effect of sintering temperature on TiO2 nanoflower catalyst on porous Ti gas diffuser anodes

Abstract

Electrochemical heterogeneous catalytic ozonation (E-catazone) is a promising and advanced oxidation technology that uses a titanium dioxide nanoflower (TiO2-NF)-coated porous Ti gas diffuser as an anode material. Our previous study has highlighted that the importance of the TiO2-NF coating layer in enhancing (OH)-O-center dot production and rapidly degrading O-3-resistant drugs. It is well known that the properties of TiO2-NF are closely related to its sintering temperature. However, to date, related research has not been conducted in E-catazone systems. Thus, this study evaluated the effect of the sintering temperature on the degradation of the O-3-resistant drug para-chlorobenzoic acid (p-CBA) using both experimental and kinetic modeling and revealed its influence mechanism. The results indicated that the TiO2-NF sintering temperature could influence p-CBA degradation and (OH)-O-center dot production. TiO2-NF prepared at 450 degrees C showcased the highest p-CBA removal efficiency (98.5% in 5 min) at a rate of 0.82 min(-1), and an (OH)-O-center dot exposure of 8.41 x 10(-10) mol L-1 s. Kinetic modeling results and interface characterization data revealed that the sintering temperature could alter the TiO2 crystallized phase and the content of surface-adsorbed oxygen, thus affecting the two key limiting reactions in the E-catazone process. That is, =TiO2 surface reacted with H2O to form TiO2-(OH)(2), which then heterogeneously catalyzed O-3 to form (OH)-O-center dot. Consequently, E-catazone with a TiO2-NF anode prepared at 450 degrees C generated the highest surface reaction rate (5.00 x 10(-1) s(-1)and 4.00 x 10(-3) L mol(-1) s(-1), respectively), owing to its higher anatase content and adsorbed oxygen. Thus, a rapid O-3-TiO2 reaction was achieved, resulting in an enhanced (OH)-O-center dot formation and a highly effective p-CBA degradation. Overall, this study provides novel baseline data to improve the application of E-catazone technology. (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.