Antimicrobial and Photocatalytic Potential of a Composite of ZnO-ZnS and Activated Carbon Obtained From Banana Peel

Abstract Banana peel was mixed with zinc sulfate and pyrolyzed at 500 °C under nitrogen to synthesize a composite with potential antibacterial activity against both Gram-positive Escherichia coli and Gram-negative Staphylococcus aureus . The material was characterized by TGA, nitrogen adsorption-desorption isotherm, SEM-EDX, DRX, DRS UV-Vis, and DLS. XRD analysis showed the presence of ZnO and ZnS in the composite, and TGA analysis revealed the presence of lignocellulosic material in the solid due to decomposition peaks characteristic of hemicellulose, cellulose, and lignin. Nitrogen adsorption and desorption isotherm analysis revealed a surface area of 165.0 m 2 /g, an average pore diameter of 16.0 nm, and a total pore volume of 0.16 cm 3 /g. C, O, Zn, and Si were determined as the most significant elements present in the material. DLS showed a distribution with a single type of particle. UV-Vis analysis revealed an Eg value of 2.0 eV for the composite, indicating potential antibacterial properties and suitability for biomedical applications. The use of the material in removing sildenafil, an emerging contaminant present in various environmental matrices, was evaluated, considering the effects of parameters such as the solution pH, the catalyst dosage, and the reuse of the composite over five cycles. The composite obtained from agro-industrial waste is a promising material to remove organic contaminants from water. Graphical Abstract