Remediation of tetracycline contaminated soil and water phases by straw-derived biochar: Adsorption performance and bacterial community evolution

Tetracycline (TC), as a typical recalcitrant pollutant, posed environmental risks due to its long-term persistence. This study investigated the efficacy of straw-derived biochar (KBC800) in mitigating TC pollution in aquatic and terrestrial environments. In aqueous medium, TC was adsorbed by KBC800 primarily through film diffusion and intraparticle diffusion, dominated by physical adsorption. The adsorption capacity of TC by biochar was affected by soil constituents, yet KBC800 still exhibited a high adsorption capacity of 355 mg·g −1 . The machine learning-based extreme gradient boosting (XGB) model accurately identified total carbon (TC), humic acid (HA), and sodium chloride (NaCl) concentrations as the most critical factors influencing adsorption efficiency. Furthermore, soil amendment with 10 g·kg −1 KBC800 improved soil properties, enhanced microbial diversity, stimulated plant growth, and alleviated phytotoxicity. Microbial community analysis revealed the positive effects of KBC800 on microbial community structure, with Conexibacter and Paucibacter emerging as dominant genera. Notably, KBC800 addition reduced the stimulatory impact of TC on soil microorganisms. These findings demonstrated the potential of biochar for effective remediation of antibiotic-contaminated environments and provided insights for straw biomass valorization. • Biochar KBC800 with a high specific surface area was successfully prepared via pyrolysis. • K 2 CO 3 modified biochar (KBC800) has high adsorption capacity for TC in water. • The adsorption process involves both physical and chemical adsorption. • KBC800 can improve the negative effects of TC on soil and cabbage. • KBC800 promotes microbial remediation of TC stress.