Rational Design of a Carbon‐Based Heterogeneous Photo‐Fenton Catalyst for Enhanced Methylene Blue Degradation Under Visible Light

Abstract

ABSTRACT Developing efficient heterogeneous photo‐Fenton catalysts with broadened pH adaptability remains important for sustainable wastewater treatment. In this work, a carbon‐based catalyst (C‐KFS) containing Fe‐based active phases was rationally designed and applied to methylene blue (MB) degradation under visible light. Structural characterization confirmed the successful loading of Fe‐containing species on the carbon carrier, providing abundant active sites and favorable interfacial properties. Under optimized conditions, C‐KFS achieved 99.2% MB removal within 30 min and retained 92.1% of its activity after five consecutive cycles, with low Fe leaching. The catalyst was evaluated over a tested pH range of 3‐9 and maintained high degradation efficiency particularly within pH 3‐6, indicating improved pH tolerance compared with conventional homogeneous Fenton systems. Under the studied conditions, the degradation kinetics can be described by an apparent pseudo‐first‐order model with a rate constant of 0.128 min −1 . Mechanistic analysis suggests that the enhanced activity arises from the synergistic effects of visible‐light‐assisted Fe redox cycling, H 2 O 2 activation, and reactive oxygen species generation. The present study mainly evaluates MB degradation/decolorization rather than directly verified complete mineralization, but it nevertheless provides a useful strategy for constructing carbon‐based heterogeneous photo‐Fenton catalysts for wastewater treatment.