Simultaneous removal of tetracycline and antibiotic resistant bacteria/genes in UV-LED/H2O2 system: Competitive interactions and wavelength dependence

The coexistence of emerging containments, such as antibiotic resistant bacteria (ARB), antibiotic-resistant genes (ARGs) and antibiotics, potentially influence elimination efficiencies in UV light-emitting diode (UV-LED) alone and UV-LED/H 2 O 2 system as their complex interactions. Tetracycline (TC) degradation efficiency ( k F ) correlated closely with its UV molar absorbance ( R 2 = 0.831) in UV-LED alone system and with • OH yield ( R 2 = 0.999) in UV-LED/H 2 O 2 system across studied wavelengths (265, 280 and 310 nm). The k F values for intracellular DNA (i-ARGs) also exhibited a high correlation with UV-LED wavelengths in both systems ( R 2 = 0.997–0.999). The coexistence of TC and ARB/ARGs resulted in a mutual inhibition of their degradation efficiencies due to competition for photons and • OH, along with the consequent reduction in intracellular ROS within ARB, with their degradation efficiencies exhibiting marked dependence on wavelength in both systems. Notably, the UV-LED/H 2 O 2 system at 265 nm effectively achieved the simultaneous removal of TC, ARB and ARGs with minimal energy consumption, and successfully fragmented ARGs. The degradation pathway of TC was analyzed, and the biotoxicity of its degradation intermediates demonstrated the environmental friendliness and safety of UV-LED/H 2 O 2 technology. This study elucidated the competitive interactions between antibiotics and ARB/ARGs within UV-LED/H 2 O 2 system, providing a promising approach for their simultaneous removal while ensuring energy efficiency. The competition between TC and ARB/ARGs for UV photons and • OH, along with the consequent reduction in intracellular ROS within ARB, resulted in a mutual inhibition of their removal efficiencies. The UV-LED/H 2 O 2 system at 265 nm achieved simultaneous removal of TC, ARB and ARGs, with minimal energy consumption.