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Characterization and environmental application of iron-modified zeolite from the Zlatokop deposit

In this paper, characterization of iron-modified zeolite (IMZ) from the Zlatokop deposit and its potential environmental application has been described. The modification procedure includes treatment of natural zeolite (NZ) with Fe(NO3)3 in an acetate buffer at pH = 3.6 followed by treatment with NaOH and NaNO3. The properties of NZs and IMZs have been determined by analysis of their chemical composition, specific surface area and by X-ray powder diffraction method (XRPD), scanning electron microscopy-energy dispersive X- ray analysis (SEM-EDS), TG-DTG and FTIR analyses. The chemical behaviour of modified zeolite has been examined in the zeolite-ultrapure water system at adjusted initial pH values in the range of 1.71–5.08, and also by determining the zero- point charge. The NZ and IMZ samples have been tested relative to the uptake of zinc ions. The results have shown that the capacity of IMZ samples for zinc ions is three-to-four times higher compared to the NZs. The balance of exchangeable ions before and after zinc uptake confirms an almost complete stoichiometric relation for both zeolite samples indicating ion exchange as the main process. However, in IMZ samples ion exchange takes place inside the zeolite particle and on activated zeolite particle surface.

Natural zeolite; Iron-modified zeolite; XRPD; SEM-EDS; FTIR; TG-DTG

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