Ultra-high adsorption of tetracycline antibiotics on garlic skin-derived porous biomass carbon with high surface area

In this article, a garlic skin-derived porous biomass carbon (GSP-BC) material with an ultra-high specific surface area was prepared using KOH as an activator. The morphology and structure of the GSP-BC were evaluated. The ultra-high surface area, average pore diameter and total pore volume of the GSP-BC are 3686 m2 g−1, 2.43 nm and 1.96 cm3 g−1, respectively, which enable the GSP-BC to have an outstanding adsorption capacity of 1911.8 mg g−1 for tetracycline hydrochloride (TCH). Some important variables such as initial concentration (300–800 mg L−1), contact time, solution pH (3–10), ionic strength, and temperature (290–313 K) were investigated systematically. The experimental data of adsorption kinetics and isotherms were well fitted by the pseudo-second-order model and the Freundlich model, respectively. Furthermore, the adsorption process was spontaneous and endothermic. Moreover, the GSP-BC has excellent adsorption capacity for other tetracycline antibiotics. The findings reveal that it is feasible to use garlic skin waste as the precursor to prepare porous biomass carbon with high surface area.