Na-montmorillonite to Fe(II)-Mt using ferrous citrate/ascorbate obtained by dissolving iron powder
| Title | Na-montmorillonite to Fe(II)-Mt using ferrous citrate/ascorbate obtained by dissolving iron powder |
| Publication Type | Journal Article |
| Year of Publication | 2022 |
| Authors | Chikkamath, S, Manjanna, J, Momin, N, Hegde, BG, Nayaka, GP, Kar, AS, Tomar, BS |
| Journal | Applied Clay Science |
| Volume | 217 |
| Pagination | 106396 |
| Date Published | FEB |
| Type of Article | Article |
| ISSN | 0169-1317 |
| Keywords | Ascorbic acid, Bentonite, Citric acid, Cr(VI) reduction, Fe(II)-montmorillonite, Iron dissolution |
| Abstract | Bentonite containing montmorillonite (Mt) as the major clay mineral is the potential buffer material of engineered barrier system in the deep geological repository for high-level waste management. The corrosion products of canister/or overpack material (carbon steel) may alter the basic characteristics of bentonite through Fe/clay interaction and formation of FeMt to certain extent. A convenient method is required for quantitative preparation of Fe(II)-Mt because the only few direct methods reported have some limitations. For this, weak ferrous complexes having good solubility to facilitate the cation-exchange with bentonite is essential. Therefore, Fe(II)-citrate, Fe(II)-ascorbate and Fe(II)-citrate/ascorbate were obtained here by dissolving the iron powder (Fe0) in citric acid (CA), ascorbic acid (AA) and their equimolar mixtures from 25 mM to 300 mM at 70 °C under N2 atmosphere. The redox potential was measured to monitor the dissolution of Fe0 in these mild organic acids. Higher dissolution of Fe0 occurred in CA + AA mixture. The dissolved iron in the form of ferrous complex was reasonably stable in inert atmosphere, Fe2+/Fetotal ≈ 1. The parent clay mineral (bentonite, NaMt) was treated with Fe(II) − cit/asc to form Fe(II) − Mt. through cation exchange process. The CEC and ferrous to ferric ratio of the Fe(II)-Mt was close to the stoichiometric amount. The XRF, XRD, ac impedance, FT-IR, TGA/DSC, XPS and FE-SEM are used for further characterization. In-situ complexation reaction of interlayer Fe2+ ions in Fe(II)-Mt with o-phenanthroline was also observed. |
| DOI | 10.1016/j.clay.2021.106396 |
| Type of Journal (Indian or Foreign) | Foreign |
| Impact Factor (IF) | 5.467 |
Divison category:
Physical and Materials Chemistry
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