Engineered biochar for advanced oxidation process towards tetracycline degradation: Role of iron and graphitic structure

The excessive accumulation of tetracycline (TC) presents significant challenges to both human health and the ecological environment. This study explores the impact of Fe-loaded sawdust graphitic carbon (engineered biochar) on TC degradation in water, utilizing an advanced oxidation process facilitated by H₂O₂ activation. The investigation encompasses an examination of the structural characteristics of Fe-loaded sawdust graphitic carbon and an in-depth analysis of its catalytic degradation mechanism concerning TC. Density functional theory (DFT) was utilized to construct an adsorptive degradation system for TC in water, thereby scrutinizing the optimal treatment process for TC. The findings highlight that Fe-loaded biochar exhibits not only a substantial pore structure but also inherent defects and a graphitic structure. The porous configuration enhances the TC adsorption capacity of the biochar system, while the graphitic structure bolsters the stability of the carbon framework, ensuring efficient charge transfer via the carbon defects. The activation effect of Fe(III) on H₂O₂ into ·O₂^- is dependent on its specific location within the carbon structure. In the presence of 5 mmol H₂O₂, Fe-loaded biochar achieves a nearly 100 % degradation rate of TC, with its degradation proficiency minimally influenced by varying pH conditions.