Gasification slag–corn root composite for the removal of tetracycline: Adsorption performance and mechanism

This study demonstrates a potential pathway for valorizing agricultural and industrial residues by developing a metal-enriched biochar composite (GS/CR-MBC) from corn roots (CR) and gasification slag (GS) via one-step co-pyrolysis. The resulting composite is a mesoporous material. It possesses a specific surface area 22 times greater than that of pristine GS and over 45 times that of CR-derived biochar. The material exhibited a high tetracycline adsorption capacity of 858.7 mg/g and could be regenerated effectively, retaining over 89 % of its initial capacity after five cycles. The adsorption process following the Langmuir isotherm model and pseudo-second-order kinetics. The primary adsorption mechanisms included ligand exchange, coordination complexation, hydrogen bonding, and π–π interactions. These findings highlight the promise of synergistically converting low-value residues into functional materials, supporting the development of a more sustainable and circular bioeconomy.