Relationship between Chemical Durability, Structure and the Ionic-Covalent Character of Me-O-P Bond (Me = Cr, Fe), in the Vitreous Part of the System 60P2O5-2Cr2O3-(38 - x) Na2O-xFe2O3 (with 3 ≤ x ≤ 33 mol%) - Advances in Materials Physics and Chemistry

AMPC > Vol.9 No.10, October 2019

Relationship between Chemical Durability, Structure and the Ionic-Covalent Character of Me-O-P Bond (Me = Cr, Fe), in the Vitreous Part of the System 60P₂O₅-2Cr₂O₃-(38 - x) Na₂O-xFe₂O₃ (with 3 ≤ x ≤ 33 mol%) ()

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DOI: 10.4236/ampc.2019.910015 533 Downloads 1,269 Views Citations

Author(s)

Nadia Beloued¹, Radouane Makhlouk¹, Yassine Er-Rouissi¹, M’hammed Taibi², Mohammed Sajieddine³, Said Aqdim^1,4*

Affiliation(s)

¹Laboratory of Materials Engineering for Environment and Valorization, Faculty of Sciences, Hassan II University Ain Chock, Casablanca, Morocco.
²Physico-Chemistry Laboratory of Inorganic and Organic Materials ENS, University Md V, Rabat, Morocco.
³Physics and Mechanics of Materials Laboratory, Faculty of Sciences and Technical, Sultan Moulay Slimane University, Beni Mellal, Morocco.
⁴Mineral Chemistry Laboratory, Department of Chemistry, Faculty of Science, Hassan II University Ain Chock, Casablanca, Morocco.

ABSTRACT

The structure and chemical durability in the vitreous part of the system 60P₂O₅-2Cr₂O₃-xFe₂O₃-(38 - x)Na₂O phosphate glasses (with 3 ≤ x ≤ 33 mol%) were investigated using various techniques such as IR spectroscopy, X-ray diffraction and M?ssbauer spectroscopy. The presence of Cr₂O₃ and the increase of Fe₂O₃ at the expense of Na₂O in the glass network lead to a large number of covalent and rigid Fe-O-P and Cr-O-P bonds. The infrared and XRD spectra indicate a radical change of structure and show that the increase of the Fe₂O₃ content favors the depolymerization of the vitreous network towards pyrophosphate chains. The presence of Cr₂O₃ in the glass seems to favor the covalent Cr-O-P bonds linked to the most probable cyclic metaphosphate chains. However, when the Fe₂O₃ content increases (≥23 mol%), its impact on the glass network is stronger than that of Cr₂O₃. The infrared and XRD spectra indicate a radical change of structure and show that the increase in Fe₂O₃ content favors the depolymerization of the vitreous network to short pyrophosphate chains. The results of M?ssbauer spectroscopy indicate the presence of both Fe (III) and Fe (II) ions which occupied more or less deformed octahedral sites. The growth of the glass transition temperature (Tg) with the increase of the iron oxide in the vitreous network, leads to an improvement of the glass rigidity. This explains the decrease of the ionic radius of the iron and the reinforcement of the interconnection of the chains of vitreous networks. The structure of sodium-chromium-iron phosphate glasses can be considered largely as pyrophosphate units linked to ferric and ferrous ions in octahedral or deformed octahedral coordination. The dissolution rate is 200 times lower than that of the silicate glasses.

KEYWORDS

Chemical Durability, Phosphate Glasses, Chromium and Iron Oxides, IR, XRD, Nuclear and Chemical Wastes

Share and Cite:

Beloued, N. , Makhlouk, R. , Er-Rouissi, Y. , Taibi, M. , Sajieddine, M. and Aqdim, S. (2019) Relationship between Chemical Durability, Structure and the Ionic-Covalent Character of Me-O-P Bond (Me = Cr, Fe), in the Vitreous Part of the System 60P₂O₅-2Cr₂O₃-(38 - x) Na₂O-xFe₂O₃ (with 3 ≤ x ≤ 33 mol%). Advances in Materials Physics and Chemistry, 9, 199-209.
doi: 10.4236/ampc.2019.910015.

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