Photo-Fenton-like catalytic performance of FeOCl/HPMC/PAM composite hydrogel for organic pollutant degradation under natural light

Though advanced oxidation technologies show promise for water purification, they face challenges. Photocatalysts struggle with recoverability and environmental adaptability, while the Fenton process is limited by the finite cycling of Fe species, low H 2 O 2 utilization, and strict acidic pH requirements. Based on the above issues, this paper developed a novel FeOCl-loaded hydroxypropyl methylcellulose/polyacrylamide (HPMC/PAM) composite hydrogel (FeOCl/HPMC/PAM) is developed as an efficient photo-Fenton-like catalyst. The FeOCl/HPMC/PAM composite system exhibits complex degradation kinetics (zero-order reaction with 5–50 μL hydrogen peroxide solution, first-order reaction with 100 μL hydrogen peroxide solution) and demonstrates highly efficient degradation performance across a broad pH range (1–7). Under pH= 7, it achieves 93.47 % methylene blue (MB) degradation within 60 min via an adsorption-degradation synergistic mechanism. After six cycles, it retains 75 % activity, showing favorable reusability. The cyclic stability test shows that it still retains 75 % of the degradation efficiency after 6 consecutive cycles, confirming its reliable reusability. Meanwhile, the iron leaching rate of the composite material during the reaction is only 0.061 mg/L, confirming its structural stability and environmental safety. With low cost, easy recovery, and wide pH adaptability, this composite hydrogel exhibits potential as a commercially viable system for organic pollutant removal from real water matrices.