Studies into the ion exchange and intercalation properties of AlH2P3O10•2H2O

Marsh, Thomas P. (2011). Studies into the ion exchange and intercalation properties of AlH2P3O10•2H2O. University of Birmingham. Ph.D.

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Abstract

This thesis describes investigations performed into the ion exchange and intercalation properties of aluminium triphosphate, AlH\(_2\)P\(_3\)O\(_{10}\)•2H\(_2\)O (AlTP). Materials synthesised were characterised using a variety of techniques, including powder neutron and X-ray diffraction, Rietveld analysis, thermogravimetic analysis and environmental scanning microscopy. Monovalent ion exchange (with Na, K, Rb, Cs and Ag) gave complete and facile exchange of the host’s hydrogen ions and gave crystalline products. A thermodynamically favoured phase with two waters of crystallisation was observed for all monovalent cation exchanges. The alkali metals also showed metastable phases with differing numbers of waters of crystallisation, four for Na and one for K, Rb and Cs. Unit cells have been assigned to the exchanged phases, with all showing a more than doubling of the \(a\) parameter. Structural characterisation of the rubidium and caesium phases show this to be a result of a change of symmetry to C2/c causing adjacent layers to shift half a unit cell along [010] with respect to one another. Ion exchange with divalent cations (Cu, Mn, Zn, Ca and Sr) has also been shown to be possible, with phases showing altered XRD patterns and decomposition products. Intercalation with a range of increasingly complex amines was found to be possible in AlTP. Multifunctional molecules, including amino acids, were also found to intercalate into AlTP, with evidence in the intercalation of 6-aminohexanoic acid that interactions between intercalated molecules within the inter-lamellar region are possible. Trends were found to be similar to other layered phosphates with respect to the amounts and angles of intercalation of simple monoamines and the effects of pK\(_b\) and sterics upon an amines ability to intercalate into AlTP. In addition, intercalation with silver exchanged AlTP was also found to be possible. This was able to intercalate several similar amines to AlTP, but showed its own unique intercalation properties including the ability to intercalate thiols.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):