Synthesis and ion exchange of germanate materials

George, Ryan (2019). Synthesis and ion exchange of germanate materials. University of Birmingham. Ph.D.

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Abstract

This work focuses on exploring new materials for potential effluent treatment with regards to caesium and strontium uptake. A germanate derivative of the natural mineral umbite has been investigated for potential ion exchange properties, this work explores the viability of this material as an exchanger and attempts to modify its exchange properties.
Subsequent ion exchange results shows both caesium and strontium uptake by zirconogermanate umbite (K2ZrGe3O9.H2O) but at low levels. This is substantially improved by chemical modification of the umbite structure with the replacement of Zr by 25% Nb/Sb at the octahedral site. High resolution synchrotron X-ray powder diffraction data shows complex structural behaviour of these doped materials when they undergo caesium exchange.
Further attempts at doping higher levels for Zr results in mixed phases with in formation of pharmacosiderite phases (HK3Ge7O16.4H2O and HK3Ti4Ge3O16.4H2O), with these also showing interesting ion exchange properties. The thermal decomposition products of the pharmacosiderite phases have also been analysed for potential wasteform candidates.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):