Boosting Heterogeneous Fenton Catalytic Reactivity for p-Nitrophenol Degradation via Embedding Magnetic Fe3O4 Nanoparticles on Chitosan Aerogel

This study presents a novel magnetic nanoparticle (MPs)-decorated chitosan aerogel (CSA) composite as an efficient and eco-friendly catalyst for the Fenton oxidation of high-concentration p-nitrophenol (PNP). The MPs/CSA composite was synthesized via co-precipitation and systematically characterized using X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller multimolecular layer adsorption, and high-resolution transmission electron microscopy. Strikingly, under optimal conditions for PNP degradation at a high concentration of 2000 mg/L via the Fenton reaction, MPs/CSA-3, with 0.7 g of Fe₃O₄ NPs loaded on CSA, a catalyst dosage of 4.6 g/L, and a H₂O₂ concentration of 5.0 g/L, achieved a 91% removal efficiency within 60 min, following a pseudo-first-order kinetic model with a rate constant of 0.0417 min⁻¹. Compared to pure Fe₃O₄ NPs, the composite exhibited significantly enhanced catalytic activity and was easily separated from the solution via vacuum filtration within 5 s, achieving approximately 80% catalytic degradation. These findings highlight the potential of MPs/CSA as a cost-effective and efficient catalyst for removing hazardous organic pollutants in wastewater treatment.