Preparation of β-cyclodextrin/dopamine hydrochloride-graphene oxide and its adsorption properties for sulfonamide antibiotics

To develop high-efficiency antibiotic adsorbents, β-cyclodextrin and dopamine hydrochloride were used to modify graphene oxide to prepare a new type of ternary composite material (β-cyclodextrin/dopamine hydrochloride-graphene oxide, CD-DGO). The material was characterized using scanning electron microscopy, Fourier infrared spectrometry, transmission electron microscopy, and specific surface area optical analysis. Two typical sulfonamides antibiotics (sulfamethoxazole, sulfadiazine) adsorption capacity were evaluated in terms of the dosage of composite materials, the ratio of each component, and the pH of the solution. We analyzed the adsorption characteristics via adsorption kinetics and adsorption isotherms, and then investigated the stability of the adsorbent through desorption and regeneration of the adsorbent. The results show that the adsorption effect of sulfonamides antibiotics is best at pH = 2; the adsorption kinetics conform to the pseudo-second-order kinetic model, and the adsorption equilibrium follows the Langmuir adsorption isotherm; the maximum adsorption capacity of CD-DGO for sulfamethoxazole and sulfadiazine is 144 mg·g^-1 and 152 mg·g^-1, respectively. The material has good reusability, and the dominant force in the adsorption process is the π-π electron conjugation effect with hydrogen bonding. This offers a theoretical basis for the treatment of sulfonamides antibiotics water pollution.