Preparation, characterization and studies of the adsorbing efficiency of the iron oxide-silica nanocomposite material

Abstract

Composite material is a material composed of two or more distinct phases (matrix phase and dispersed phase) and having bulk properties significantly different form those of any of the constituents. Nanocomposites are composites in which at least one of the phases shows dimensions in the nanometer range (1 nm = 10-9m). In the present study a novel method for preparing Fe2O3-SiO2 nanocomposite materials is presented. Iron (III) oxide was prepared by electrochemical method. SiO2 was prepared by basic hydrolysis of the tetraethylorthosilicate (TEOS). This study shows the influence of silica on the structure, size, and distribution of the Fe2O3 particles in the Fe2O3-SiO2 systems. The structural characterization of the synthesized materials was performed by X-ray diffraction, FT-IR, Scanning Electron Microscopy (SEM), EDS and DTA/TGA. The present study introduces a good alternative method for Cr (VI) removal from aqueous solutions by adsorption, allowing the development of newer, lower operational cost, and more efficient technology than other processes already in use. Adsorption was found to be dependent on pH and initial concentration of Cr(VI) solution. Results of adsorption studies suggest that pristine iron oxide and silicon (IV) oxide removes 72.10% and 24.73% respectively. The iron oxide – silicon (IV) oxide nanocomposite, prepared in this work, removes 93.88% Cr(IV) from aqueous solution. Therefore, it can be concluded that iron oxide–silicon (IV) oxide nanocomposite is a potential adsorbent for adsorption of Cr(VI) from aqueous solution. Studies of the sorption kinetics show that equilibrium adsorption was attained in 20 minutes depending on other experimental conditions. The kinetic data justified Lagergren first-order kinetic equation. Adsorption isotherm study showed that the results fulfilled the Langmuir Model of adsorption isotherm.