Sulfonic Acid Functionalized SBA-3 Silica Mesoporous Magnetite Nanocomposite for Safranin O Dye Removal

Abstract

At the present study, sulfonic acid functionalized SBA-3 silica mesoporous magnetite nanocomposite (Fe3O4@SiO2@SBA-3- SO3H) was synthesized and its adsorption ability for removing Safranin O dye from aqueous samples was investigated. X-ray diffraction analysis (XRD), vibrating sample magnetometer (VSM), energy dispersive X-ray spectroscopy analysis (EDX), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the adsorbent. The FESEM images confirmed the synthesis of nanocomposites with good morphology and size below 30 nm. The experimental variables affecting the removal efficiency were optimized by Taguchi orthogonal array experimental design method (L16 array). At the optimal conditions (pH = 6, ionic strength = 0.005 mol L− 1, sample volume = 25 mL, adsorbent weight = 0.12 g and contact time = 15 min) the efficiency for Safranin O removal was obtained as higher than 91%. The pseudo-first-order, pseudo-second-order, intra particle and Elovich kinetic models were investigated, and the kinetic data followed the pseudo-second-order kinetic model (R2 = 0.9999). Also, the study of three isotherm models (Langmuir, Freundlich and Temkin) showed that Freundlich isotherm was suitable for describing Safranin O adsorption (R2 = 0.9941, n = 1.428). The reusability experiments showed high removal efficiency of Safranin O after 9 cycles of usage. Finally, the results of Safranin O removal from the aqueous real samples showed the applicability of this nanocomposite for Safranin O removal applications.