Thesis--University of Missouri, School of Mines and Metallurgy, 1907. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed December 5, 2008)

A number of symmetric porphyrins containing both zinc(II) and lead(II) central metal ions have been prepared. Several routes to these compounds have been investigated and their merits evaluated. The conjugation of the chromophores has been extended by the inclusion of different <I>trans</I>- substituted arylethynyl substituents in the <I>meso</I>-position. An improved multigram method for the preparation of [bis-trimethylsilyethynylporphinato]zinc(II), which does not necessitate chromatographic purification, is described. The use of [5-triisopropylsilylethynylporphinato]zinc(II) for the preparation of donor/acceptor prophyrins via Sonogashira coupling, several of which were prepared, is also described. Investigations of the binding of 4(3<I>H</I>)pyrimidone with [5,5'-bis-[10,20-bis(3,5-di-<I>tert</I>-butylphenyl)-15-tri-iso-propylsilylethynyl-porphinyl]-1,3-butyn-1,4-diyl]dizinc(II) were made. The association constant was found to be 2500 ± 140 mol^-1 (ΔG = -4.6 Kcal/mol), significantly greater than that for 4(3<I>H</I>)pyrimidone alone (444 ± 5 mol^-1), as determined by NMR dilution experiments. The crystal structures of [5,15-bis(3,5-bis-<I>tert</I>-butylphenyl)porphinato]zinc(II), [5,15-bis-(3,5-di-<I>tert</I>-butylphenyl)-10,20-bis-triisopropylsilylethynylporphinato]lead(II), [5,10,15,20-<I>tetrakis</I>-triisopropylsilylethynylporphinato]lead(II), 5,15-bis-(3,5-bis-<I>tert</I>-butylphenyl)-10,20-bis-phenylethynylporphyrin, [5,15-bis-(3,5-bis-<I>tert</I>-butylphenyl)-10,20-bis-(3-hydroxy-3-methyl-butynyl)porphinato]zinc(II),5,10,15,20-<I>tetrakis</I>-triisopropylsilylethynylporphyrin and [5,15-bis-(3,5-bis-<I>tert</I>-butylphenyl)-10-(4-N, N-dimethylaminophenylethynyl)-20-triisopropylsilylethynylporphinato]zinc(II) are also described.

Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.

The major aim of this study was to investigate various leaching methods for the recovery of zinc and lead from blended neutral leach residues of &Ccedil / inkur having a composition of 12.59 % Zn, 15.21 % Pb, 6.45 % Fe, 0.054 % Cd. Initially water leaching tests were performed at various conditions of leaching temperature, reaction time and particle size. The optimized conditions for water leaching were found to be 2 h, 95&amp / #61616 / C and 250 g/l pulp density with a final pH of 5.9. However, the zinc recovery value of 10.26 % was not adequate for industrial scale operations itself. In acid leaching trials / acid concentration, temperature, reaction time and particle size were the chosen variables. At the optimized condition of 150 g/l H2SO4, 95&amp / #61616 / C, 2 h at 250 g/l pulp density with a final pregnant solution pH of 4.2, the extraction values were determined as 74.87 % for Zn and 39.59 % for Fe. These recovery values were evaluated as suitable for industrially feasible operations while creating a secondary leach residue of a composition of 4.10 % Zn, 19.17 % Pb, 5.52 % Fe and 85 ppm Cd that would not be suitable for pyrometallurgical lead production. After recovering zinc in considerable amount by hot sulphuric acid leaching, NaCl leaching experiments for the extraction of lead were done on the secondary leach residue by taking temperature, time and pulp density into account. The most promising conditions of brine leaching for lead recovery were found as 300 g/l NaCl, 20&amp / #61616 / C, 15 minutes and 20 g/l pulp density that gave approximately 82 % lead recovery with a final residue of 7.87 % Pb, 6.86 % Zn, 8.79 % Fe.

Sorption of quaternary metal ions (Pb2+, Cu2+, Cd2+ and Zn2+) was carried out on lignite from the South Moravia. Following experiments were tested: kinetic sorption, dependence of sorption on pH, initial concentration, temperature, effect of electrolytes (KNO3 and NaCl) and desorption in deionized water. Sorption studies was carried out in quaternary mixtures and in the case of inicial concentration effect additional in a single-component solution. The batch sorption experiments was used. Sorption time was 24 hour, although concentration of ions was a near equilibrium after two hour. As the optimal pH was determined pH 5. The order of affinity by lignite was obtained Pb >> Cd > Zn > Cu for the sorption of metals in the single-component solution and the order was Pb > Cu > Zn > Cd for the sorption of mixture of metals. The maximum adsorptium capacities from single solutions were for Pb 97,82 mg/g, Cd 60,34 mg/g, Zn 49,88 mg/g and Cu 30,28 mg/g and in the case of ones from mixture solutions were for Pb 39,03 mg/g, Cu 25,94 mg/g, Zn 15,21 mg/g and Cd 5,18 mg/g. Experimental data have been analysed using Langmuir and Freundlich model. Thermodynamic values H°, S° and G° were calculated. Desorption test showed that desorption efficiency is 0–3 %. NaCl had the greatest influence on sorption from electrolytes. On the basis obtained results we can say that metals are binding to lignite in particular due to chemical interactions. Lignite is s suitable as a sorption material for metal ions especially in the field of low concentrations.

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