Structural Refinement, Morphological Features, Optical Properties, and Adsorption Capacity of α-Ag2WO4 Nanocrystals/SBA-15 Mesoporous on Rhodamine B Dye

Abstract

α-Ag2WO4 nanocrystals, mesoporous silica (SBA-15), and α-Ag2WO4/SBA-15 as a nanocomposite were prepared by sonochemical, hydrothermal, and in situ sonochemical methods respectively. Samples were characterized by X-ray diffraction (XRD), Rietveld refinement, micro-Raman, Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption, ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy, and Zeta potential. XRD patterns, Rietveld refinement, and XPS spectra confirmed the formation of α-Ag2WO4, SBA-15, and α-Ag2WO4/SBA-15. XPS spectra evidenced the formation of metallic silver during analysis. FE-SEM images illustrated the deposition of α-Ag2WO4 nanocrystals mainly on the external surface of SBA-15. N2 adsorption data showed that the textural properties of α-Ag2WO4/SBA-15 were similar to pure SBA-15. Zeta potential data demonstrated that all samples synthetized have negatively charged surface. The materials were tested as adsorbents for the dye cationic rhodamine B. The adsorption behavior of rhodamine B onto α-Ag2WO4, SBA-15, and α-Ag2WO4/SBA-15 correspond to Langmuir adsorption isotherm and pseudo-second-order kinetics. The maximum adsorption capacity of α-Ag2WO4/SBA-15 was up to 150 mg g−1 and 99% removal efficiency for RhB 20 mg L−1 in 15 min. Furthermore, 80% of RhB could be recuperated from adsorbents at pH 7.