Efficiency and mechanism of enhanced norfloxacin removal using amorphous TiO₂-modified biochar

Inadequate treatment of antibiotic-contaminated wastewater, including compounds such as norfloxacin (NOR), poses a substantial treat to both ecological safety and human well-being. An innovative approach was devised to address NOR pollution using amorphous TiO₂ modified biochar (A-TiO₂/BC) prepared via sol-gel impregnation. The resultant had a commendably specific surface area of 131.8 m²/g^-1, which was 1.91 times more than the original surface area of unmodified BC. A-TiO₂/BC also exhibited abundant hydroxyl and oxygen-containing functional groups, thereby provided adequately active sites for NOR adsorption. R² values obtained from NOR isotherm adsorption models descended in order of Freundlich < Temkin < Sips < Langmuir, which indicated that the NOR removal by A-TiO₂/BC mainly complied with monolayer adsorption accompanied by heterogeneous surface adsorption. Under weakly acidic conditions, NOR adsorption benefits from the synergistic physicochemical interactions of A-TiO₂ and BC. Notably, A-TiO₂/BC demonstrated an impressive NOR adsorption capacity of up to 78.14 mg g^-1, with a dosage of 20 mg L^-1 at 25 °C under pH 6. Such A-TiO₂ modified biochar thus presents a promising alternative for NOR removal.