Wet de-NOx Processof the Composite Phosphate Rock/H<sub>2</sub>O<sub>2</sub> Slurryby Calcination Modification: Key Componentsand Radical Generation
Wet flue gas denitrification offers a new route for converting industrial nitrogen oxides (NOx) into highly concentrated nitrate wastewater. This study presents a novel H<sub>2</sub>O<sub>2</sub>-based advanced oxidation process that utilizes the composite calcined phosphate rock to activate H<sub>2</sub>O<sub>2</sub> for efficient NOx removal. The calcination treatment for composite phosphate rocks was found to enhance de-NOx efficiency and capacity by varying the CaMg(CO<sub>3</sub>)<sub>2</sub> and Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH contents and creating oxygen vacancies. A systematic investigation of the phase structural evolution under alkaline H<sub>2</sub>O<sub>2</sub> conditions identified CaMg(CO<sub>3</sub>)<sub>2</sub> and Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH as the primary active components, with CaMg(CO<sub>3</sub>)<sub>2</sub> preferentially participating in the reaction. Radical quenching experiments and time-resolved electron paramagnetic resonance (EPR) analysis confirmed the predominant roles of superoxide radicals (O<sub>2</sub><sup>•–</sup>) and surface-bound hydroxyl radicals (<sup>•</sup>OH<sub>surface</sub>) in NOx oxidation. A mechanistic pathway was proposed, highlighting the synergistic effects of reactive oxygen species (ROS) and mineral phase transitions on NOx removal. The proposed NOx purification method offers a promising option for nitrogen recovery and NOx pollution control.
Publication Details
- Journal
- Figshare
- Published
- 2025-03-15
- DOI
- https://doi.org/10.1021/acsestengg.4c00951.s001
- Primary Topic
- Mycorrhizal Fungi and Plant Interactions
- Type
- article
- Field-Weighted Citation Impact
- 0.00