Comparative study of eriochrome black T (EBT) dye adsorption utilizing direct growth of cost-effective efficient materials: S-doped ZnO nanoparticles, ultrathin nanoflakes, and nanowalls

In the present studies, zinc oxide (ZnO) nanoparticles were synthesized by the non-aqueous sol-gel route and incorporated with diverse amounts of the nonmetal element like sulfur with different concentration (1, 2, 4, and 6 wt%). Furthermore, the physicochemical properties of all synthesized nanoparticles were characterized by Xray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), N 2 adsorption/desorption isotherms, and ultra violate visible (UV-Vis) absorption spectra. Powder XRD analysis shows the formation of hexagonal wurtzite phase of ZnO and the incorporation of S atom in ZnO lattice was confirmed by the XPS analysis. FESEM results reveal that the synthesised S-doped (2, 6 wt%) ZnO samples possess the growth of 1D ultra-thin nanoflakes with sharp edge and vertically aligned 1D thin nanowalls morphology. Moreover, UV-Visible transmission spectral studies showed that the optical energy band gap of ZnO NPs were reduced by S doping. After that, pure ZnO, 1, 4, and 6 wt% S-containing ZnO samples were examined as for adsorption study of eriochrome black T (EBT) dye. Among the S-containing samples, 50 mg of the adsorbent, doped with 4 wt% S (4 wt% S-ZnO) could adsorb up to 95.13 % of EBT dye (15 ppm) in 90 min. Therefore, such a sulfure doped ZnO samples in the form of nanoparticles (NPs), nanoflakes (nanosheets) as well as nanowalls could be used as a promising material for the application in industrial wastewater treatment processes.