Green, Sustainable Synthesis of γ-FeO/MWCNT/Ag Nano-Composites Using the Leaf Extract and Waste Car Tire for Removal of Sulfamethazine and Bacteria from Wastewater Streams.

Multi-walled carbon nanotubes (MWCNTs) decorated with Ag nanoparticles (NPs) are bifunctional adsorbent nanomaterials with antibacterial activity. They can be magnetically recovered from wastewater in case of coupling with γ-FeO. In this study, for the first time, an environmentally friendly technique was applied to prepare a nanocomposite (NC) material composed of γ-FeO/MWCNT/Ag by using Bridgestone disposable tires and leaves extract. γ-FeO/MWCNTs/Ag NC was employed for the removal of sulfamethazine (SMT) from aqueous solutions. Under the optimized conditions determined via the Taguchi method, the highest SMT adsorption capacity of the γ-FeO/MWCNT/Ag NC was measured to be 47.6 mg/g. The experimental data fitted well with the pseudo-second-order kinetic model and the Langmuir isotherm. The thermodynamic parameters implied that the adsorption process was endothermic. In addition to adsorption of the drug pollutant, the NC demonstrated a superior antibacterial activity against Gram-positive bacteria. The reusability test also showed that over 79% SMT can be removed using γ-FeO/MWCNTs/Ag NC even after four adsorption cycles. Taken together, γ-FeO/MWCNTs/Ag NC was proven to be a promising antibacterial nano-adsorbent for wastewater treatment.