Hierarchical porous biochar with enhanced performance inspired by “corn straw/cow manure co-compost” designed for efficient removal of antibiotics

In this study, corn straw (CS) was processed using two pretreatment routes, namely corn straw/cow manure co-composting and solid fermentation with a homologous microbial community isolated from cow manure. The pretreated materials were converted into biochar (BSC-3 and BSF-3) through carbonization-activation. Changes in microbial communities and their effects on straw composition and structural characteristics were investigated through comparative dynamic analysis. The characterization results indicated that compared with the biochar produced directly from raw straw without pretreatment (BCS), the biochars derived from both co-composting and solid fermentation pretreatments exhibited superior physicochemical properties. The specific surface areas of BSC-3 and BSF-3 were 2946.21 and 2504.56 m 2 /g, respectively. The total pore volumes increased to 1.8422 and 1.4721 cm 3 /g, representing increases of 45.6–71.3% and 47.2–79.4% over BCS. This enhancement was mainly attributed to two factors. First, microbial pretreatment disrupted the lignocellulosic structure, thereby generating more porous precursors for activation. Second, the mycelial structures introduced during microbial modification contributed additional microstructural features favorable for biochar formation. In adsorption experiments using hydrochloric tetracycline (TH) and sodium sulfadiazine (SD-Na) as model antibiotics, the biochars exhibited outstanding adsorption performance. The maximum adsorption capacities reached 1513.56 and 1422.45 mg/g for TH, and 1281.65 and 1258.85 mg/g for SD-Na, exceeding those of previously reported adsorbents. In addition to producing high-performance biochar for efficient antibiotic removal from water, this study verified the feasibility of microbial community pretreatment for improving the functionality of the derived biochar, providing a promising strategy for the development of lignocellulosic biochars. • Composting and solid fermentation were employed to treat straw for the preparation of biochar. • The physi-chemical properties of biochars through different methods were compared and analyzed. • Biochars have large surface area, highly pore volume, and contain abundant functional groups. • The adsorption capacities of biochars for TH and SD-Na are are higher than most adsorbents.