Degradation of antibiotic tetracycline using H2O2/TiO2/UV/microwave system

Abstract

In this study, we report the effective decomposition of the antibiotic tetracycline (TC), which contaminates the aquatic environment using a H2O2/TiO2/UV/microwave system. The addition of hydrogen peroxide or irradiating the decomposition reaction solution with microwaves during decomposition could not individually generate OH radicals. However, when a microwave discharge lamp (MDL) was used in addition to the hydrogen peroxide during the decomposition, many OH radicals were generated with more than 90% TC decomposition. Likewise, using microwaves and ultraviolet light (from the MDL) together with hydrogen peroxide showed a positive synergistic effect on TC decomposition. Meanwhile, during the decomposition of TC using the H2O2/TiO2/UV/microwave system, we expected a reduction in molecular weight by N-demethylation, hydroxylation, dehydration, and ring-opening reactions, and finally mineralized into CO2, H2O, and N-minerals. This study highlights the importance of OH radicals in the decomposition reaction and a method of efficiently generating OH radicals during decomposition using hydrogen peroxide. Finally, the developed new advanced oxidation process (AOP) was judged to be sufficiently applicable for removing organic compounds that are difficult to decompose in aquatic environments.