Preparation and application of SiO₂-Fe₂O₃ and SiO₂-Fe₂O₃-Fe for soot oxidation: A step toward decarbonization by...

The article presents a method for obtaining catalytic systems: SiO₂-Fe₂O₃, SiO₂-Fe₂O₃-Fe and verification of their catalytic properties in the oxidation process of technical soot N550. The process of immobilization of Fe³⁺ ions on microsilica-SiO₂ was investigated in the batch system (equilibrium, kinetics, thermodynamics). The process was aimed at obtaining a system with a developed surface and using less iron while maintaining the same catalysis active surface. In the next stages, the SiO₂-Fe³⁺ systems were modified to obtain SiO₂-Fe₂O₃ and SiO₂-Fe₂O₃-Fe materials, which exhibited catalytic properties. To obtain catalytic systems, the processes of Fe³⁺ ions sorption, iron oxide precipitation - Fe₂O₃ and Fe reduction using a plant extract were used. Catalytic systems were applied in the N550 technical soot oxidation process to reduce the conversion temperature and increase its efficiency. The soot oxidation process was carried out in a muffle furnace using variable process parameters, i.e. temperature (450, 475, 500, 525 and 550^oC), time (1, 2 and 3h), type of catalytic system (SiO₂-Fe₂O₃, SiO₂-Fe₂O₃-Fe) and its % content relative to the constant mass of soot (0, 10, 20 and 30%). The greatest increase in the conversion efficiency of soot particles was obtained using the SiO₂-Fe₂O₃ system with a content of 20% at a temperature of 550^oC and for 3 h.