The experimental work described in this thesis is
aimed at the elucidation of the speciation of the zinc
and germanium 8-hydroxyquinoline systems. A knowledge
of this speciation could aid in modelling the kinetics
of solvent extraction of zinc and germanium with 7alkyl
derivatives of 8-hydroxyquinoline.
In this study the stability constants of the ligand 8hydroxyquinoline
with the ions H+, Zn2+ and Ge4+ have
been investigated by potentiometry at 25°C in a
partially aqueous medium. A titration technique was
used in which the hydrogen ion concentration was
monitored using a glass indicating electrode. The
partially aqueous medium comprised of O. 1 mol dm- 3
NaCl04 in 60% (v/v) dioxane and the concentration
levels of the reagents were at least millimolar. The
analysis of the potentiometric data was carried out
with the aid of the computer programs HALTAFALL, ESTA
and STATGRAPHICS.
The results obtained for the systems involving the H+
and Zn2+ ions compare with those reported in the
literature. The stability constant of a protonated
species in the zinc-8-hydroxyquinoline system (ZnLH)
was established for the first time. Precipitates
obtained from the Zn2+ titrations were identified as
zinc 8-hydroxyquinolate dihydrate.
The germanium 8-hydroxyquinoline system has not been
studied previously via potentiometry techniques. The
complex hydrolysed species of germanium in aqueous
solutions and the unusual features displayed in the
formation curves increased the complexity of species
selection. Although a suitable model of the species
present could not be determined some evidence suggests
the presence of protonated species. Hence, a
prerequisite for resolving the germanium-8hydroxyquinoline
system could be a more complete
understanding of the hydrolysis of germanium in the
partially aqueous medium used. / Thesis (M.Sc.)-University of Natal, Durban, 1991.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/5849 |
| Date | January 1991 |
| Creators | Maharaj, Vanitha. |
| Contributors | Martincigh, Bice S., Salter, L. F. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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