Structural characteristics of modified natural zeolite

Natural zeolite of Slovak provenience has been modified with magnetic nanoparticles at selected temperatures of 20, 50 and 85 °C with the aim to enhance its sorption properties. The pore, surface and structural properties of zeolite/iron oxide composite were characterized using nitrogen adsorption measurements, electron probe microanalysis and powder X-ray diffraction. The crystallinity of the host zeolite was strongly influenced by the temperature of iron oxide particles precipitation, but it was still retained. It followed from the nitrogen adsorption measurements that the surface area and the pore volume of zeolite composites have increased in relation to the precipitation temperature, the best sorption properties were revealed at the composite prepared at 85 °C. As followed also from the SEM images, the iron oxide nanoparticles being of size 30 nm are forming mesoporous aggregates adsorbed on the zeolite surface. Fractal analysis used to describe the modified geometry of zeolite composites has given the values of surface fractal dimension between 2.36 and 2.51.