A novel Cu9S8 antibacterial based on magnetic chestnut shell biochar for the removal of sulfonamides in water environment: Differential adsorption and mechanism study

Abstract 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 highest adsorption capacity of SMZ on Cu₉S₈ was 33.4 mg/g 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. coil) 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.