Desulfurization characteristics and mechanism of iron oxide-modified bio-carbon materials

To meet the requirements of efficient adsorption of the atmospheric pollutant SO2 and low energy consumption regeneration of adsorbents, metal oxide-modified biomass carbon materials were prepared by microwave heating, and the effects of microwave power, iron oxide loading, and calcination time on the activated carbon load with iron oxides (ACIO) were investigated. The desulfurization mechanism of ACIO was characterized by multiple methods, and the process was simulated using density functional theory (DFT). The results indicated that the optimum preparation conditions were as follows: the loading amount of iron oxides was 10 wt%, the microwave power was 500 W, and the calcination time was 10 min. The adsorption capacity of ACIO corresponding to the optimum preparation conditions was 146.31 mg/g, and the thermal conductivity was 0.58 W/(m·K), which led to a reduction in the regeneration energy consumption by approximately 2800 J/g. Furthermore, ACIO exhibited good SO2 cyclic adsorption-desorption performance, and the SO2 adsorption capacity after five cycles of adsorption and desorption was maintained at 46.98 mg/g. The DFT calculation results indicate that chemical adsorption between SO3 and Fe2O3 under anhydrous conditions occurred during the desulfurization process and contributed to the sulfate formation reaction.