Mechanism of singlet oxygen production from PDS mediated by [Bmim][Tf2N]: an innovative and designable activation method

Recent years, persulfate (PS) activation has mainly relied on metal ion activation, carbon materials, and their doped counterparts. However, traditional methods exhibit numerous limitations. Ionic liquids (ILs), due to their customizable nature, offer new potential for targeted non-radical catalysis. In this study, 1-butyl-3-methyl-1H-imidazol-3-ium bis((trifluoromethyl)sulfonyl) amide ([Bmim][Tf 2 N]) was used to enhance peroxydisulfate (PDS) activation for degrading oxytetracycline (OTC), achieving almost complete degradation in just 20 minutes. The mechanism revealed that the imidazole ring in the [Bmim][Tf 2 N] cation acts as an electron donor, promoting the cleavage of the O-O bond in the PDS and generating 1 O 2 . And, the iminium nitrogen in the anion acts as an electron acceptor, facilitating the breaking of the S-O bond in the PDS twice in succession, further producing 1 O 2 . This represents a successful application of ILs for PDS activation, providing new insights into designing efficient, targeted catalytic methods.