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

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 550oC), 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 550oC and for 3 h.