Zn-regulated thermal reconstruction of LDH(Co/Al)@ZIF-8 derived catalysts for peroxymonosulfate activation: Mechanism and practical application in antibiotics removal

A Zn dosage-mediated thermal reconstruction strategy was proposed to fabricate LDH@ZIF derived catalyst. • Moderate Zn addition achieves uniformly dispersed ZnCo 2 O 4 spinel. • Optimized LZ-0.2 removes levofloxacin rapidly through multiple ROS pathways involving 1 O 2 . • The catalyst realizes stable 144 h continuous degradation in fixed-bed reactor. Peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) are effective for refractory antibiotic removal, yet conventional layered double hydroxide (LDH) catalysts often suffer from lamellar collapse, active site aggregation and poor pore accessibility after calcination. Herein, a series of LDH(Co/Al)@ZIF-8 derived catalysts (LZ-x) were prepared through the growth of ZIF-8 on LDH(Co/Al), followed by pyrolysis, for PMS activation and levofloxacin (LFX) degradation. Regulating the Zn dosage controlled ZIF-8 growth and the subsequent thermal reconstruction of the hybrid precursor. Among them, LZ-0.2 exhibited an open hierarchical architecture and the highest catalytic activity, achieving 95.11% LFX removal within 5 min with a k obs of 0.576 min −1 . In addition, structural characterization indicated that an appropriate Zn dosage favored the formation and dispersion of ZnCo 2 O 4 -containing spinel domains within the porous nanosheet architecture. Meanwhile, mechanistic investigations supported a hybrid radical/non-radical oxidation pathway involving 1 O 2 , •OH, SO 4 •- and • O 2 − . Additionally, the LZ-0.2 + PMS system maintained effective performance in various real water matrices and stable fixed-bed operation for 144 h in hospital wastewater, with low Co and Zn leaching. Moreover, phytotoxicity, antibacterial activity, and zebrafish developmental toxicity were reduced after treatment. This work highlights Zn-dosage regulation as an effective strategy for directing the thermal reconstruction of LDH@MOF derived catalysts for efficient PMS activation and antibiotic abatement.