Microwave-assisted facile one-pot method for preparation of BiOI-ZnO nanocomposites as novel dye adsorbents by synergistic collaboration

In this study, BiOI-ZnO nanocomposites, as novel adsorbents, were successfully prepared using microwave-assisted facile one-pot method at 6 min without using any surfactants or templates. The as-prepared nanocomposites were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive analysis of X-ray spectroscopy, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, Fourier transform-infrared spectroscopy, thermogravimetric analysis, and Brunauer-Emmett-Teller surface area analysis. In the nanocomposites, ZnO and BiOI have wurtzite hexagonal and tetragonal crystalline phases, respectively, and the phases do not change with composition. The as-prepared samples were used for adsorption of methylene blue and rhodamine B from aqueous solutions. The results show that the nanocomposite with 80 % BiOI has superior dye adsorption capacity. The nanocomposites have high dye adsorption rates and majority of them are adsorbed after about 25 min. Kinetic and adsorption isotherm studies show that the data follow pseudo-second-order kinetic model and Langmuir isotherm, respectively.