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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Optimization of Polymer Enhanced Diafiltration system by studying copper removal from aqueous solutions using Lambda-carrageenan

Mathur, Aditi 28 August 2008 (has links)
"Excessive discharge of heavy metals has been one of the major causes of water pollution worldwide. Various traditional methods of heavy metal removal have been devised but certain drawbacks like high cost, high energy requirement, and the production of toxic sludge have limited their use. Hence, biosorption is one of the alternative methodologies. This study combined biosorption and diafiltration in an attempt to optimize Polymer Enhanced Diafiltration to study copper removal from aqueous solutions by the use of a biopolymer, lambda-carrageenan. Lambda-carrageenan was studied as a biosorbent owing to properties such as low cost, good water solubility, non-gelling nature and the presence of sulfate groups which can sequester cations. Conditions for binding such as pH, temperature and concentration of copper and lambda-carrageenan were studied. Equilibrium dialysis experiments were performed to study the metal ion membrane transport kinetics and to determine the metal ion binding capacity and strength of the copper-biopolymer association. Rheological measurements were performed to determine how the viscosity of lambda-carrageenan changes with increase in shear stress and with increase in metal concentration. The solution was found to be shear thinning. However, with increase in metal concentration, viscosity was found to increase when high concentrations of polymer (8 g/L and 12 g/L) were used. Solution viscosity was found to decrease with increase in metal concentration when 4 g/L of polymer was used. Polymer Enhanced Diafiltration studies showed no leakage of the polymer through the membrane and no significant binding elsewhere in the PEDF system. It also showed an impressive retention of copper inspite of a rather high metal ion-polymer dissociation constant suggesting a yet not understood series of events occurring on the membrane of the PEDF system. Lambda-carrageenan is a linear polysaccharide, which might be stacking up on the membrane after forming layers, and not allowing any free metal ion to escape. Other reasons could be the sieving effect, degradation of the polymer due to shear and compaction of molecule on metal binding such that the polymer is not itself escaping through the membrane, but also not allowing the free metal ion to escape. Hence, this study suggests the need for more information on the metal-polymer interactions on the surface of the membrane by designing a direct observation experiment with a mini-tangential flow filtration system."
2

Studium plazmatické vazebnosti radiofarmak / Study of plasma protein binding of radiopharmaceuticals

Hafinec, Václav Matyáš January 2013 (has links)
Study of Plasma Protein Binding of Radiopharmaceuticals Summary The purpose of this work is the study of binding of substances (177 Lu-DOTA- [Lys3]bombesin, 177 Lu-NOTA-[Lys3]bombesin, 177 Lu-PCTA-[Lys3]bombesin, and 177 Lu- DOTA-MG47) to plasma proteins by equilibrum dialysis in 37řC, particularly using plasma samples of beef, rabbit, rat and human. Within this group, these substances were compared interspecifically. The substances 177 Lu-DOTA-[Lys3]bombesin, 177 Lu-NOTA-[Lys3]bombesin, 177 Lu- PCTA-[Lys3]bombesin, and 177 Lu-DOTA-MG47 are the newly developed receptor- specific radiolabeled peptides. For all the newly collected data, the interspecific comparison and subsequent statistical evaluation was performed. The indicated bombesin derivates were compared and statistically analyzed even between themselves. During the interspecies comparisons and the determination of the statistical significance of the data, there were found statistically significant and statistically highly significant differences between some of the examined samples. A highly significant difference was found during comparing with samples of 177 Lu-NOTA- [Lys3]bombesin and statistical evaluation, there was found a statistically highly significant difference. Despite the differences found, it is clear that the plasma binding concerning...

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