Simultaneous Removal of Four Dye Pollutants in Mixture Using Amine Functionalized Kit-6 Silica Mesoporous Magnetic Nanocomposite

Abstract

In this study, Kit-6 silica mesoporous was created on the surface of magnetite core having silica shell and functionalized by amine group to form Fe3O4@SiO2@Kit-6/NH2 mesoporous magnetic nanocomposites (MMNCs). The synthesized nanocomposite was applied as adsorbent for the removal of four mixed dyes including Sunset Yellow, Rhodamine B, Ponceau 4R and Brilliant Blue from aqueous mixtures. The characterization of the synthesized nanocomposites was investigated by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM) and X-ray diffraction (XRD) analysis. N2 adsorption–desorption method (at 77 K) confirmed the mesoporous structure of synthesized Fe3O4@SiO2@Kit-6/NH2 MMNCs. The surface area was obtained as 241.68 m2 g−1 (Brunauer- Emmett- Teller, BET method). All of the experimental variables influencing the dyes removal efficiency were investigated using L16 Taguchi orthogonal array design. Under optimum conditions (contact time = 20 min, pH = 2, adsorbent weight = 0.08 g (3.2 g L−1) and sample volume = 25 mL); more than 92% of dyes were removed. Adsorption data were studied using Langmuir, Freundlich, and Temkin models to find the best isotherm model. Also, the sorption kinetics were investigated and the best extent of fitting was achieved by the pseudo-second order kinetic model (R2 = 0.999). The results showed fast kinetics and high removal efficiency of adsorbent, making it as a recoverable adsorbent for removal of these dyes.