Investigation of the Adsorption Properties of a New Composite Catalyst for the Fenton System

The influence of the structure of the SiO2 layer on the adsorption properties of magnetosensitive CoFe2O4/SiO2/CuO nanocomposites created as catalysts for the Fenton system was studied. For this, the formation of the SiO2 layer was carried out by the sol-gel method using surfactants of synthetic and natural origin. To determine the process parameters, a previously proposed mathematical model of the dye adsorption process from an aqueous solution was used. The presented model considers dye adsorption from an aqueous solution as a pseudo chemical reaction of displacement of the solvent molecules from adsorption sites on the adsorbent surface by the adsorbate molecules. It has been established that the process of formation of the SiO2 layer is influenced by surfactants (sodium dodecyl sulfate or rhamnolipids), and the adsorption properties of the prepared CoFe2O4/SiO2/CuO composites depend on the structure of the stabilizing SiO2 layer. The kinetic parameters of the methylene blue (MB) adsorption process from aqueous solutions at concentrations of (2 - 5)•10-5 mol/L were determined. The obtained results are perfectly fitted by the proposed pseudo-first-order equation. The calculated value of the activation energy of MB adsorption on the CoFe2O4/SiO2(RL)/CuO catalyst indicates the physical adsorption of the dye. The results of using the investigated composites in the Fenton system as catalysts for the oxidation process of the organic dye MB are shown.