Cost-effective Fe-Cu-Cr oxide/activated-carbon catalyst for peroxymonosulfate-driven degradation of p-nitrophenol

p-Nitrophenol (p-NP) is a toxic and persistent pollutant commonly found in industrial wastewater, necessitating efficient and economically viable treatment strategies. In this work, we develop a low-cost and high-performance catalyst consisting of Fe-Cu-Cr mixed metal oxides supported on activated carbon (AC), synthesized through a simple impregnation-calcination method and applied for peroxymonosulfate (PMS) activation.Systematic optimization of preparation parameters revealed that HCl pretreatment of activated carbon, a ternary Fe-Cu-Cr composition, a 20 wt% metal loading, and calcination at 600 °C yield the highest catalytic activity, achieving p-NP degradation with Ct/C₀ ≈ 0.25 after 4 h. Notably, the total treatment cost can be maintained below 30 CNY per ton of wastewater, demonstrating a substantial economic advantage over reported catalytic systems. Mechanistic studies show that p-NP degradation follows a synergistic adsorption-catalysis pathway, wherein activated carbon enriches p-NP at the catalyst surface and multivalent metal oxides efficiently activate PMS to generate reactive oxygen species, primarily •OH. This work introduces a practical, scalable, and cost-effective catalyst design using earth-abundant metals, offering a promising avenue