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TitleThe use of hydrotalcite as an anion absorbent
Publication TypeJournal Article
Year of Publication1995
AuthorsParker, L.M., Milestone N.B., and Newman R.H.
JournalIndustrial and Engineering Chemistry Research
Pagination1196 - 1202
Date Published1995
ISSN08885885 (ISSN)
KeywordsAbsorption spectroscopy, Anion absorbent, Carbon dioxide, Carbonate minerals, Firing (of materials), Hydrotalcite, Ion affinity, Ion exchange, Ions, Mass spectrometry, nuclear magnetic resonance spectroscopy, Pyrolysis, Sorption, Synthesis (chemical), Thermogravimetric analysis, X ray diffraction
AbstractThe high affinity of Mg/Al hydrotalcite for carbonate anions means that it cannot be reversibly exchanged and so prevents its use as an anion-exchange material. However, carbonate can be removed by thermal decomposition, evolving CO 2. The resultant material sorbs anions when placed in solution and returns to the hydrotalcite structure. This work showed that hydrotalcite can be used as an anion absorbent by firing, anion sorption, exchanging in carbonate, and repeating the cycle. Ion exchange, XRD, TGA/MS, and 27Al NMR results showed that after the first firing and rehydration cycle, the hydrotalcite structure becomes disordered, with its sorption capacity reduced by ∼50%. Further firing/sorption cycles cause only a slow degradation in structure. © 1995 American Chemical Society.

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