Preparation and Denitrification Performance of Sodium Humate/TiO₂ Composite Nanoparticles

Graphical In this paper, Sodium humate/TiO 2 composite nanoparticles (HA-Ti) were synthesized via a hydrothermal method, exhibiting uniform nanowire morphology with enhanced specific surface area and mesoporous structure. Synergistic interactions between HA-Na and TiO 2 significantly improved NO removal efficiency, driven by optimized oxygen-containing functional groups and interfacial charge transfer, offering an eco-friendly strategy for efficient NO x control and low-grade coal valorization. Notably, the post-denitrification products, rich in humic acid derivatives, can be directly repurposed for the production of humic acid compound fertilizers. Humic acid (HA) can be efficiently extracted from low-grade coal, a sustainable approach that enhances resource utilization efficiency while simultaneously addressing environmental concerns associated with the accumulation of extensive weathered coal reserves. In this study, sodium humate/TiO₂composite nanoparticles (HA-Ti) were developed via a hydrothermal synthesis method by integrating sodium humate (HA-Na) with TiO 2 . The effects of process parameters on the structural and functional properties of HA-Ti were systematically investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). Denitrification performance was evaluated under varying hydrothermal conditions, including duration, temperature, and NaOH concentration. Results revealed that the incorporation of TiO₂ nanoparticles significantly enhanced the specific surface area (147.91 m 2 /g) and pore structure of HA-Na. The composite demonstrated significantly enhanced physicochemical activity compared to pristine HA-Na, attributed to the synergistic interaction between HA-Na and TiO 2 . HA-Ti exhibited exceptional denitrification performance, achieving an NO removal efficiency of 83.8% under optimized conditions. This work highlights the potential of HA-Ti composites as an eco-friendly and efficient solution for NO x pollution control, while advancing the high-value utilization of low-grade coal resources.