Preparation and Spectroscopic Characterization of Iron Doped Mullite

Abstract

Abstract. A novel method for preparation of Fe2+ /Fe 3+ substituted mullite is described. Aluminosilicate gels are applied as precursors instead of crystalline aluminosilicates as used in other common syntheses. The process is composed of three stages. First, iron is introduced into a homogeneous aluminosilicate gel by ion exchange. The gel is converted to a mixture of mullite and amorphous silica in a 1263 K 3 h isothermal calcination in the the second stage. Finally, in order to obtain the nano-scale pure mullite phase the formed amorphous silica is removed by a dissolution in alkaline media. The components formed in various stages of the process are characterized by 57 Fe Mössbauer and Fourier transform infra red spectroscopies, X-ray diffraction method and scanning electron microscopy. Spectroscopic and diffraction methods helped the identification of the mullite phase. Mössbauer measurements revealed the presence of both Fe 2+ and Fe 3+ states providing a chance for perspective catalytic application of the obtained Fe-mullite.

Research on the natural features of karst water, on the example of some water intakes

“…According to many authors, (Patrick, 1976;Preka-Lipold et al, 1984, Langmuir, 1971, Thrailkill, 1976) that ratio, among other things, is an indicator of the impact of chemicals in plant production on the changes in natural properties of waters. Thus, according to Buljan (1962) the ratio of sulfate to chloride suggests the influence of fertilizer ingredients from land surfaces. Moreover, the ratio Ca / Mg <1, for example, points to the penetration of fertilizer ingredients into fresh water (Rahman and Rowell, 1979).…”

Formation of Zn and Pb sulfides in a redox-sensitive modern system due to high atmospheric fallout

“…Fe(II) doublets (D4 in Fig. 8) with isomer shift (IS) 0.85 and 0.98 mm s -1 and quadrupole splitting (QS) 1.85 mm s -1 and 2.04 mm s -1 just as Fe(III) doublets (D3) with average IS=0.39 mm s -1 and QS=1.17 mm s -1 have hyperfine parameters typical for iron in fly ash aluminosilicates from coal-burning in power plants (Ram et al, 1995;Buljan et al 2015;Smołka-Danielowska et al, 2019). Fly ash spheroidal aluminosilicates were found in the subsurface layers of the peatlands (Smieja-Król et al, 2010;Smieja-Król and Fiałkiewicz-Kozieł, 2015).…”