Periodate activation by atomically dispersed Mn on carbon nanotubes for the production of iodate radicals and rapid degradation of sulfadiazine.

[Display omitted] • Single-atom Mn catalyst is synthesized for highly effective activation of periodate. • IO 3 • is identified as the dominant ROS for the degradation of sulfonamide antibiotics. • Mn facilitates electron transfer from carbon support to IO 4 - to generate IO 3 • and MnIV/V = O. • SO 2 extrusion is the main degradation step, with products of lower antibacterial activity. • MnN@CNT/PI is a powerful AOP for removing sulfonamides from complex water matrix. Sulfonamides, such as sulfadiazine (SDZ), are widely used antibiotics that pose a significant threat to the environment due to their poor biodegradability and potential to induce antibiotic resistance. In this study, a new catalyst with atomically dispersed Mn on carbon nanotubes (MnN@CNT) was applied for the first time to activate periodate (PI) for rapid degradation of SDZ. MnN@CNT/PI system achieved 100% SDZ removal in 15 min, and the kinetic rate constant (k nor) reaches 406.1 min−1·g−2·L2, higher than those of the reported catalytic PI systems. Multiple reactive oxygen species (ROS), including IO 3 •, O 2 –•, 1O 2 , high-valent Mn-oxo complexes, and •OH, were detected, with IO 3 • being the most predominant. The Mn atom bridged the electron from the carbon support to IO 4 - via the Mn-O bond, which induced the prolonged I-O bond and thus the generation of IO 3 •. SDZ was degraded through S-N bond cleavage, pyrimidine destruction, SO 2 extrusion, and N-N coupling. The intermediate products of the SDZ degradation process showed little antibacterial activity, indicating the greatly reduced risk of the treated water to induce antibiotic resistance in the environment. The superior performance of MnN@CNT/PI in the environmental water samples suggests its high application potential for selective degradation of SDZ in complex waters. The research presents a novel advanced catalytic oxidation technology for efficiently removing sulfonamides and similar antibiotics from water for adequate environmental and ecological protection. [ABSTRACT FROM AUTHOR]