In situ grown petal-like La-doped FeCo-layered double hydroxide on carbon felt for enhanced moxifloxacin hydrochloride removal via heterogeneous electro-Fenton process.

In this study, a petal-like ternary metal-layered double hydroxide (FeCoLa-LDH) was synthesized through a facile one-step hydrothermal method and in situ grown on carbon felt (CF). The FeCoLa-LDH/CF composite electrode was applied in a heterogeneous electro-Fenton (HEF) system for the degradation of moxifloxacin hydrochloride (MOX). Characterization revealed that La-doped FeCo-LDH/CF exhibited petal-like layered structure rather than particle's structure, with higher surface defect degree and an increased electroactive surface area (ESA) compared to FeCo-LDH/CF. The composite electrode effectively degraded MOX across a pH range of 3-9. Under optimal conditions, it achieved a degradation efficiency of 92.2% within 45 min and 96.8% within 120 min. After 120 min, 82.4% of the chemical oxygen demand (COD) was removed. The superior degradation performance was primarily attributed to La doping, which enhanced electron transfer between Co/Co and Fe/Fe, promoting in situ HO generation and causing rapid conversion of HO to hydroxyl radical(•OH) on the electrode surface. Radical quenching experiments confirmed that •OH was the primary reactive species. The possible MOX degradation pathways were elucidated through liquid chromatography-mass spectrometry (LC-MS) analysis and density functional theory (DFT) calculations, and a catalytic mechanism of HEF process was proposed. Moreover, the electrode maintained 82.8% efficiency after five cycles, with lower ion leaching and broader pollutant applicability. Moreover, good degradation efficiencies of MOX were still observed in actual water bodies. Toxicity tests confirmed that MOX degradation intermediate products had low plant toxicity. This study provides a promising high-performance cathode for antibiotic removal from wastewater.