Experimental study on heterogeneous Fenton reaction oxidation of <scp>NO</scp> by reducing modified biochar loaded <scp>Fe₃O₄</scp>

Abstract Heterogeneous Fenton method stands out due to its simplicity, rapid reaction rates, low costs, and high degradation efficiency, making it an ideal candidate for NO oxidation removal in low‐temperature flue gas. The catalyst plays a crucial role in determining the catalytic efficiency of heterogeneous Fenton reaction. Biochar, characterized by its rich pore structure, abundant surface functional groups, and high adsorption strength, serves as an excellent carrier for Fenton catalysts. This paper investigates the impact of various factors on NO oxidation using biochar loaded with nano Fe 3 O 4 as the catalyst. The study identifies optimal process conditions and the improvement mechanism of reducing modification of biochar is also analyzed in depth. Results indicate that NO oxidation efficiency increases with higher concentrations and injection rates of H 2 O 2 . The optimal temperature range for the atomization zone is found to be between 150 and 170°C. Increasing the iron content in the catalyst significantly enhances NO oxidation efficiency, with an optimal iron content of approximately 50%. The reducing modification of biochar is controlled by adjusting the pH of the synthesis solution, and increasing the pH from 7 to 13 raises NO oxidation efficiency from 84.1% to 99.1%. Quantum chemical calculations further demonstrate that higher pH levels correlate with greater degrees of biochar reduction, an increased number of CC sp 2 hybrids, and enhanced electron transfer rates, all of which contribute to improved catalytic efficiency.