Significantly Enhanced Heterogeneous Fenton Degradation Ability of Phenol over Fe/HY Catalysts via Acid Treatment

Abstract In this study, a series of Fe/HY‐xM zeolite catalysts was constructed to investigate the influence of acid modification on their catalytic performance in heterogeneous Fenton‐like degradation of phenol. Among them, Fe/HY‐0.1M demonstrated the most outstanding activity, achieving over 91% phenol removal within 40 min. Moderate acid treatment (0.1 M HNO 3 ) promoted mesoporous development, enhanced the dispersion and reducibility of iron species, and increased the generation of hydroxyl radicals (·OH), as confirmed by EPR and radical quenching experiments. Despite some unavoidable iron leaching, Fe/HY‐0.1M maintained an acceptable balance between activity and stability. Moreover, the effects of key operational parameters, such as initial pH, phenol concentration, H 2 O 2 dosage, and catalyst loading, were systematically evaluated to determine optimal conditions. The Fe/HY catalyst exhibited poor activity, primarily due to the dominance of micropores, which restricted mass transfer and the aggregation of iron species, resulting in a low density of accessible active sites. Excessive acid treatment (0.15 M) caused partial framework collapse and increased Fe leaching, ultimately leading to a decline in catalytic performance. These findings provide valuable insights into the rational design of zeolite‐based catalysts for advanced wastewater treatment.