Cobalt- and copper-modified coal fly ash nanozeolites for environmental protection applications

Fly ash zeolites (FAZ) are promising materials for adsorbents, ion-exchangers and catalysts. FAZ usually possess a mixed micro-mesoporous structure that facilitates mass transport phenomena through their framework. Due to the transfer of iron spinel oxides and many metal species from the raw material, their catalytic and adsorption ability can be improved further by modifying them with metal oxide nanoparticles. In the present study, copper- (Cu-FAZ) and cobalt-modified (Co-FAZ) FAZ were prepared by incipient wetness impregnation technique, the loading of 6 wt. % copper or cobalt in the zeolite framework was achieved. Cu-FAZ and Co-FAZ were investigated by X-ray diffraction to clarify the state of Cu and Co into the FAZ matrix, while surface studies by nitrogen adsorption/desorption technique were carried out to trace the effect of modification on the FAZ surface characteristics. Modified and parent FAZ were investigated as adsorbents and catalyst for decontamination of water and gases from organic pollutants. The simultaneous presence of Fe2+/Fe3+ and Cu2+/Fe3+ or Co2+/Fe3+ species in the modified FAZ stipulates easier oxygen release essential for organic degradation. The favorable combination of morphological and compositional peculiarities of modified FAZ contributes to their effective organic removal performance. Acknowledgements This work was financially supported by the National Science Funds, Ministry of Education and Science of Bulgaria under contract DN 17/18 and under Grant DNTS Slovak Republic 01/6.