Mechanism of sulfamic acid modified biochar for highly efficient removal of tetracycline

In this work, a novel modified biochar was prepared by pretreatment of Camellia oleifera shell with sulfamic acid. The effects of sulfamic acid on the properties of feedstock and biochar, and the influence of pyrolysis temperature on the modification was investigated. Furthermore, the adsorption mechanism of modified biochar for tetracycline (TC) was explore. The results showed that the specific surface area (170.97 m²/g) of the modified biochar was 2.6 times larger than that of the original biochar (65.31 m²/g). In addition, sulfamic acid treatment introduced more functional groups for biochar. These modification effects significantly improved the adsorption performance of biochar. The maximum adsorption capacity of sulfamic acid modified biochar for TC was 412.95 mg/g. The adsorption mechanism studies demonstrated that there were many interactions in the adsorption process, including electrostatic interaction, H bonding, π-π interaction, pore filling. In general, sulfamic acid was a potential green modification reagent, which could be used to improve the adsorption performance of biochar.