Boosting peroxymonosulfate activation for complete removal of gatifloxacin by a bead-chain zeolitic imidazolate framework composite

A bead-chain metal-organic framework composite was designed and synthesized by assembling a zeolitic imidazolate framework (ZIF) onto manganese dioxide (MnO₂) nanowires. The prepared catalyst MnO₂@ZIF-X (X = 1, 2 and 3) was used to facilitate gatifloxacin (GAT) degradation by using potassium peroxymonopulfate (PMS) as an activator. MnO₂@ZIF-2 exhibited excellent catalytic performance, achieving 100 % degradation of GAT (10 mg/L) in the presence of PMS (1 mM) in 15 min, and the toxicity of the majority of degradation intermediates decreased. Furthermore, the removal efficiency was maintained above 90 % throughout a wide pH range (3-11) and in the coexistence of anions ( [Formula: see text] , Cl^-, SO₄^2-). The main mechanism of the MnO₂@ZIF-2/PMS system involves the synergistic effect of radicals and non-radicals (single linear oxygen and electron-mediated transfer), making the system highly resistant to interference from environmental matrices. Moreover, the GAT degradation pathway was elucidated through intermediate analysis and theoretical calculations. In particular, MnO₂@ZIF-2 was well dispersed on a microporous filter membrane to create an immobilized membrane reactor that displayed excellent catalytic performance for the continuous degradation of GAT for 300 min. This work offers an avenue for the design of catalysts with good catalytic activity, particularly for PMS activation in antibiotic wastewater remediation.