Abstrakt

The concept of magnetic photocatalysts with separation function requires ferromagnetic material with high magnetic susceptibility to an external magnetic field to enable recycling of composite nanoparticles. Currently, much attention is devoted to functionalization of photocatalyst using MFe2O3, where M =Fe, Zn, Co, Mn. However direct contact between photocatalyst and magnetic iron oxide particles leads to photodissolution of iron ions into the solution during irradiation and, as a consequence, nanocomposite poisoning as well loosing the magnetic and photocatalytic properties. In order to overcome leaching of iron ions into the solution core addition of silica, polymer or carbon inert layer between the magnetic core and the TiO2 shell is applied (Fig. 1-b). In this regard, the aim of present study is to better understand the effect of the preparation procedure on magnetic properties and photocatalytic activity of spinel MFe2O3 ferrites. The pH of the solution and corresponding zeta potential was found to be essential for appropriate formation of ferrite core/silica interlayer/TiO2 shell nanocomposite, since the electrical charge controls interactions during functionalization of the magnetic core particles (see in Fig. 2). Further, Pt-Cu metallic particles were deposited on magnetic photocatalyst surface using photodeposition and chemical reduction methods. The correlation between surface properties of magnetic nanocomposites and photocatalytic activities was studied. The effect of the metal loadings on carbamazepine oxidation pathways, and finally its mineralization, measured as total organic carbon (TOC) reduction was investigated. The obtained magnetic photocatalysts were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), specific surface area (BET), diffuse reflectance spectroscopy (DRS) and vibrating sample magnetometer (VSM) analysis. The highest photooxidatation rate of carbamazepine, measured as TOC reduction was observed for Pt-modified magnetic photocatalysts. The enhanced activity was related to a decrease in metal particle size, an increase in the adsorption sites and efficient separation of char ge carriers.

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