Reducing the molecular oxygen activation energy barrier by increasing Fe-O bonds to eliminate antibiotics and their resistance genes

Abstract

Sulfamethoxazole (SMX) and its antibiotic resistance genes (ARGs) are potential threats to public health. Microwave catalytic technology is an efficient environmental remediation technology, and a reasonable design of the catalyst enables the system to achieve an ideal remediation effect under low microwave power. In this study, a microwave catalyst (FeCO-2) that activates molecular oxygen (O₂) was designed on the basis of rational theoretical organization. Density functional theory (DFT) calculations were used to predict the catalytic performance of FeCO-2 in the microwave field. The mechanism of active substance generation and successful construction of the MW/FeCO-2 catalytic system were verified by experimental studies. The abundance of Fe-O bonds alters the electronic structure of the iron carbide material (Fe@C), adjusts the conduction band potential of the material, reduces the reaction energy barrier, facilitates exciton dissociation under microwave, and facilitate O₂ activation. The application of the MW/FeCO-2 system was verified with secondary effluent from a farm wastewater treatment process: 90.62% SMX and over 86.77% of ARGs were removed within 15 min. This study provides a new technique to efficiently simultaneously eliminate antibiotics and their resistance genes. In addition, this study provides ideas for the construction of a microwave catalytic system and explains the mechanism of the microwave catalytic process.