Sunlight-mediated removal of endocrine disruptors from wastewater using trimetallic core-shell Ag-TeO2@ZnO nanocomposites

The current work emphasizes the preparation of trimetallic core-shell Ag–TeO2@ZnO nanocomposites (NCs) by thermo-mechanical method for the efficient photocatalytic degradation of 2,4-Dichlorophenol and β-naphthol pollutants. FE-SEM shows that Ag and TeO2 nanoparticles are deposited on the surface of ZnO nanotubes. The band gap of pristine ZnO NPs and 5 wt% Ag–TeO2@ZnO nanocomposites are found to be 3.16 and 2.96 eV, respectively. The calculated specific surface area (SBET) of pristine ZnO NPs and 5 wt% Ag–TeO2@ZnO nanocomposites are 40.47 and 45.66 m2/g respectively, confirming that Ag and TeO2 nanoparticles contribute to increasing in surface area of pure ZnO. The synthesised nanocomposite showed excellent photocatalytic performance for the degradation of β -naphthol (95.6%) in 40 min at the concentration of (0.6 mg/ml) and 2,4-DCP (99.6%) in 180 min (0.4 mg/ml) under natural sunlight. Cyclic Voltammetry and Electrochemical Impedance Spectroscopy were carried out to study the electrochemical properties. The determination of reactive oxygen species (ROS) confirmed that the degradation of the pollutants by 5 wt% Ag–TeO2@ZnO NCs was due to the formation of superoxide radicals. Electron paramagnetic resonance revealed the presence of sharp signals in pure ZnO nanoparticles at g ∼1.95 and oxygen vacancy peak at g ∼2.01 in 5 wt% Ag–TeO2@ZnO NCs. To study the mechanism behind the degradation of pollutants, Scavenger test using histidine and ascorbic acid (ROS scavengers) was performed. The synthesised nanocomposites are highly stable and showed enhanced efficiency up to three cycles, confirming their reusability as a photocatalyst.

Post-Dr. Rukiye Öztekin is currently working as a researcher at Dokuz Eylül University, Department of Environmental Engineering. Post-Dr. Rukiye Öztekin studied her master education at Dokuz Eylül University Department of Environmental Engineering on “Color removal from textile wastewater in sequencing batch reactor”. Post-Dr. Rukiye Öztekin completed her doctorate education at Dokuz Eylül University Department of Environmental Engineering on “Effect of sonication on the treatment of toxic and refractory industrial wastewaters”. Post-Dr. Rukiye Öztekin completed her post-doctorate education at TÜBİTAK with a scholarship on “The production of methane gas from carbon dioxide”. She has many international publications.