Enhanced Fe3+/Fe2+ cycle by a novel 2D/2D FeS/ACN composite for rapid photo-Fenton degradation of tetracycline-based wastewater

Caiwen Wu; Shan Huang; Xing Cao; Zexiong Huang; Yanjuan Zhang; Zuqiang Huang; Huayu Hu; Tao Gan

doi:10.1016/j.jenvman.2025.126147

Enhanced Fe³⁺/Fe²⁺ cycle by a novel 2D/2D FeS/ACN composite for rapid photo-Fenton degradation of tetracycline-based wastewater

J Environ Manage. 2025 Jun 13:389:126147. doi: 10.1016/j.jenvman.2025.126147. Online ahead of print.

Authors

Caiwen Wu¹, Shan Huang², Xing Cao², Zexiong Huang², Yanjuan Zhang², Zuqiang Huang², Huayu Hu³, Tao Gan⁴

Affiliations

¹ School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, PR China; Laibin Inspection and Testing Center, Laibin, 546100, PR China.
² School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, PR China.
³ School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, PR China. Electronic address: yuhuahu@163.com.
⁴ School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, PR China. Electronic address: gant@gxu.edu.cn.

PMID: 40516268
DOI: 10.1016/j.jenvman.2025.126147

Abstract

Fe-based photo-Fenton process is widely used to remove antibiotic in wastewater, however, the synthesis of efficient and stable catalysts to solve the problems of Fe³⁺/Fe²⁺ ions cycling and iron sludge formation of FeS-based catalysts is challenging. Herein, a strategy combining mechanical activation and pyrolysis was proposed to construct a novel FeS/amorphous carbon nitride (2D/2D FeS/ACN) composite with a two-dimensional (2D) stacked structure, where the FeS and ACN connected by Fe_x-N bonds. The removal rates of oxytetracycline, tetracycline, and chlorotetracycline over 2D/2D FeS/ACN both surpassed 96.0 % within 30 min in the photo-Fenton system, and the photo-Fenton system exhibited a much higher total organic carbon (TOC) removal than the Fenton and photo systems, giving an improvement of rate constant to 3.0 and 6.5 times, respectively. The excellent performance attributed to the fact that the photogenerated electrons were trapped by the sulfur vacancy and directed to the Fe active site for Fe³⁺/Fe²⁺ cycling via a highly-efficient charge transfer channel (Fe_x-N), resulting in efficiently circulating Fe³⁺ to Fe²⁺. Moreover, due to the involvement of photogenerated electrons in the reduction of Fe³⁺ to decrease the consumption of S (S^2- and S_n^2-), 2D/2D FeS/ACN showed superior stability after five cycles, inhibiting the formation of iron sludge. This work provides a new route for the acceleration of Fe³⁺/Fe²⁺ cycling in Fe-based photo-Fenton process for the efficient treatment of tetracycline-based wastewater.

Keywords: Amorphous carbon nitride; Fe(3+)/Fe(2+) cycle; Fe-based photo-Fenton catalysis; Tetracycline-based wastewater.