Adsorption characteristics of N-rGO for multiple representative trace antibiotics in water

Antibiotics have attracted considerable attention as pollutants; however, they have not been controlled because they cannot be effectively treated via conventional water treatment. In this study, nitrogen-doped reduced graphene oxide (N-rGO) was prepared, and its adsorption performance on multiple trace antibiotics in water was investigated by considering sulfamethoxazole, levofloxacin, clindamycin, tetracycline, penicillin, and chloramphenicol as target pollutants. The results demonstrated that the adsorption process was completed within 60 min at a removal rate exceeding 80%. The adsorption process was in line with the first-order kinetic equation and the Langmuir isothermal adsorption model, with a theoretical maximum adsorption capacity of 1,265.82 mg g^-1 . Meanwhile, the effect of pH value was related to the structure of antibiotics. Simulation studies showed that anions and cations in natural water matrix did not inhibit the adsorption process, whereas humic acid adversely affected the adsorption effect. Characterizations revealed that the N-rGO surface was wrinkled with abundant and diverse oxygen-containing functional groups, which provided suitable conditions for efficient adsorption. The results indicated that N-rGO rapidly and effectively adsorbed trace antibiotics in water, thus providing a basis for constructing an adsorption-catalytic oxidation system. Overall, the proposed method is excellent for treating trace antibiotics in a water environment.