FeVO₄ nanorods decorated natural sepiolite as highly efficient peroxymonosulfate catalyst for tetracycline degradation

Abstract

Developing a low-cost stable and high-performance peroxymonosulfate (PMS) catalyst to degrade refractory organic pollutants is still an urgent problem. Herein, this study reported FeVO₄ nanorods decorated sepiolite (FeVO₄/sepiolite) through simple hydrothermal method as an adsorptive-catalyst for PMS activation to degrade tetracycline (TC). Benefiting from the introduction of sepiolite support, FeVO₄ nanorods could be uniformly immobilized onto fibrous sepiolite surface. As a result, FeVO₄/sepiolite composite was endowed with excellent adsorption properties, rich surface hydroxyl groups, more reaction active sites, and the stable redox cycle of Fe³⁺/Fe²⁺ and V⁵⁺/V⁴⁺. Therefore, higher TC degradation efficiency (91.19% within 40 min) and larger reaction rate constant (0.1649 min⁻¹) were obtained in FeVO₄/sepiolite/PMS system than in FeVO₄/PMS system. Besides, the composite presented good stability and reusability, and the effects of application parameters on TC degradation were investigated in detail. Through quenching experiment and electron paramagentic resonance (EPR) test, it was found that both radical and non-radical species participates in TC degradation, and ¹O₂ were the main active species. The PMS activation mechanism was proposed, and the possible degradation pathway was also analyzed according to the high performance liquid chromatography-mass spectrometry (HPLC-MS) results. Overall, this work provides meaningful insights for designing natural mineral based PMS activators to effectively remediate antibiotic wastewater.

Keywords

FeVO₄ / sepiolite / peroxymonosulfate / tetracycline

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