Nanozinc ferrites @ silica as efficient adsorbent for dye removal from wastewater: synthesis and adsorption studies

Abstract

The precipitation process was successfully employed to prepare ZnFe2O4 and ZnFe2O4@SiO2 nanoparticles. The synthesized nanoadsorbents were characterized employing transmission electron microscopy (TEM), X-ray diffraction (XRD), and Brauner-Emmett and Teller (BET) methods. The potential adsorption capacities of the generated nanoparticles were assessed under various conditions, including pH, starting dye concentration, contact time, and temperature. The adsorption efficiency of ZnFe2O4@SiO2 nanoparticles (95%) was higher than ZnFe2O4 (93%). The adsorption data were described using Langmuir, Freundlich, Temkin, and Dubinin-Kaganer-Radushkevich (DKR) isotherm models. The methylene blue (MB) removal kinetics by ZnFe2O4 and ZnFe2O4@Silica nanoparticles were evaluated using linear pseudo-first-order (PFO) and pseudo-second-order (PSO) models. The removal fitted to pseudo-second-order (PSO) models as the correlation coefficient (R2) value was (0.9994). The Boyd model may be used to validate the kinetics data, and it can be deduced that the rate-determining phase was not intra-particle diffusion, but rather the hypothesized adsorption process was endothermic and spontaneous in nature. Based on the findings, ZnFe2O4@silica is an adsorbent material that may be useful in removing methylene blue from aqueous solutions.