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 H 2 O 2 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 H 2 O 2 into ·O 2 ^- is dependent on its specific location within the carbon structure. In the presence of 5 mmol H 2 O 2 , Fe-loaded biochar achieves a nearly 100 % degradation rate of TC, with its degradation proficiency minimally influenced by varying pH conditions. [Display omitted] • Fe-loaded sawdust graphitic carbon was prepared for degradation of tetracycline. • Iron can provide active sites and graphite structure for biochar. • Free radical attack dominated by ·O^2- was the main reason for TC degradation. • The adsorption capacity of Fe(III) for H 2 O 2 depends on its position on biochar. • The TC degradation pathway with Fe-loaded graphite carbon was proposed. [ABSTRACT FROM AUTHOR]