Peroxydisulfate activation by copper metal-organic framework derivatives: Deciphering the role of copper species

Metal-carbon composites can combine the respective advantages of metal materials and carbon materials, which have recently received much focus in persulfate activation. Herein, copper metal-organic framework (Cu-MOF) derived porous carbon (Cu-BTC-800) was synthesized by one-step pyrolysis, the material characterization results showed that Cu-BTC-800 was a porous carbon composite containing metallic Cu and Cu_xO (x = 1, 2). Among different copper source ratios, 1 Cu-BTC-800 exhibited optimal peroxydisulfate (PDS) activation performance and achieved 84.22 % removal of ciprofloxacin hydrochloride (CIP, 10 mg/L). Sulfate radical (SO₄˙-), hydroxyl radical (˙OH), superoxide radical (O₂˙-), and singlet oxygen (¹O₂) coexisted in this activation system, and ¹O₂ made a major contribution to CIP degradation. Most importantly, Cu₂O on the catalyst surface was verified to be the primary active site, it tended to preferentially adsorb PDS and transfer electrons to PDS, thereby inducing PDS activation to produce active species for CIP degradation. Furthermore, 1 Cu-BTC-800 displayed good reusability and stability, and this activation system was less affected by common environmental substrates, which manifested its good potential for practical applications. Finally, the possible degradation pathways of CIP were proposed, and the aquatic toxicity of the intermediate products was evaluated. This study investigated the feasibility and mechanism of Cu-MOF derivatives for PDS activation, providing an alternative option for the treatment of antibiotic-contaminated water.