Influence of the Structure on Magnetic Properties of Calcium-Phosphate Systems Doped with Iron and Vanadium Ions.

The aim of this study was to prepare and characterize the glasses made of x(Fe2O3∙V2O5)∙(100 - x)[P2O5∙CaO] with x ranging of 0-50%. The contribution of Fe2O3 and V2O5 amount on the structure of P2O5·CaO matrix was investigated. The vitreous materials were characterized by XRD (X-ray diffraction analysis), EPR (Electron Paramagnetic Resonance) spectroscopy, and magnetic susceptibility measurements. A hyperfine structure typical for isolated V4+ ions was noticed to all spectra containing low amount of V2O5. The XRD spectra show the amorphous nature of samples, apart x = 50%. An overlap of the EPR spectrum of a broad line without the hyperfine structure characteristic of clustered ions was observed with increasing V2O5 content. The results of magnetic susceptibility measurements explain the antiferromagnetic or ferromagnetic interactions expressed between the iron and vanadium ions in the investigated glass.

The role of organo-zeolitic material in supporting phytoremediation of a copper mining waste dump.

The effect of applying organo-zeolitic (OZ) amendment in supporting phytoremediation of a copper mine waste dump, using a substrate obtained from Lubietová, Central Slovakia, was studied. Three plant growth substrates were prepared: (i) the untreated substrate sample from the contaminated site (D-O), (ii) the contaminated sample treated with OZ material, with 82% D-O and 18% OZ (DO + OZ), (iii) the soil from a reference site (R). The largest amount of dry biomass was obtained from the DO + OZ sample. Whole plants grown on the original substrate (D-O) were accumulating a high concentration of Cu (3057 mg kg-1). The plants root grown on DO + OZ sample accumulated highest Cu concentrations (3127 mg kg-1), but in their aerial part, only 83.54 mg kg-1 was accumulated. The translocation factor's lower than the unit values prove that these plant species do not transfer heavy metals from root to shoot, this is why their heavy metal excluder role is evident. The value of the bioconcentration factor of the DO + OZ root/substrate obtained to be greater than the unit for Cu, Pb, Zn, Cd, Co, Ni, and Mn, suggests the OZ material's positive contribution in the phytoremediation process that can be applied for these waste dumps.