A novel hollow flower shaped Cu9S8 antibacterial agent for removing sulfonamide in water environment: effects of composite with magnetic biochar, differential adsorption, and mechanism study.

In this study, hollow nanoflower spherical Cu9S8 and Cu9S8/Fe3O4@BC with adsorption and antibacterial properties was prepared by coprecipitation and solvothermal method, respectively. The adsorption results showed that the Cu9S8 exhibited excellent adsorption performance on sulfonamide antibiotics (SAs), especially for sulfamethoxazole (SMZ). The optimal addition amount of Cu9S8 is 0.2 g, which results in a maximum adsorption capacity of 33.4 mg/g for SMZ within 120 min. The fitting results of adsorption and desorption kinetics and thermodynamics, as well as the conditions such as pH value and ionic strength were compared. It was found that different interactions led to the differential adsorption of SAs by Cu9S8. The desorption experiment further elucidated its adsorption mechanism. The large desorption capacity indicates that SAs on Cu9S8 can be further recovered and treated. The auto-deposition characteristics of Cu9S8 and the hysteresis loop of Cu9S8/Fe3O4@BC were studied to effectively recover Cu9S8 from aquatic environments. Additionally, more than 99% of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were exterminated by Cu9S8 and Cu9S8/Fe3O4@BC within 20 min. The above results suggested that the hollow nanoflower spherical Cu9S8 and Cu9S8/Fe3O4@BC composite materials can provide a new strategy for solving pollution problems and waste treatment.