The rate constants for thorium dissociation from humic acid, PMA (polymaleic acid) and PMVEMA (poly -methylvinylether/maleic acid ) were measured in the pH range of 4.20 to 5.94. The rate of thorium dissociation from these polyelectrolytes was determined by measuring the rate at which thorium was complexed with an exchange ligand. Arsenazo III was employed as the exchange ligand and its complexation of thorium was monitored by visible spectroscopy. / The dissociation of thorium from these polyelectrolytes occurred by several first order pathways. These pathways fit into two categories based on their dependence on pH, temperature and the amount of time thorium was in contact with the polyelectrolyte prior to dissociation. The first category was interpreted as dissociation of territorial bound thorium and thorium bound to specific sites on the surface of the polyelectrolyte. These types of bound thorium formed quickly and had large dissociation rate constants. Dissociation of territorial bound thorium as well as thorium bound to sites on the surface of the polyelectrolyte would be expected to have small activation energies and large negative activation entropies (from solvation of the charged group of the polyelectrolyte which releases thorium). Less than 6 (+OR-) 1 KJ/mole activation energy and between -250 (+OR-) 20 and -300 (+OR-) 20 joule/mole-(DEGREES)K of activation entropy was found for this category of thorium dissociation. / The second category of dissociation pathways was interpreted as dissociation of thorium from binding sites located within the coiled structure of the polyelectrolyte. This type of bound thorium formed very slowly and had small dissociation rate constants. The dissociation of internally site bound thorium should have large activation energies and activation entropies comparable to that for thorium bound to the surface of the polyelectrolyte. Between 20 (+OR-) 2 and 30 (+OR-) 2 KJ/mole activation energy and from -200 (+OR-) 20 to -250 (+OR-) 20 joule/mole-(DEGREES)K activation entropy was found for this category of thorium dissociation. / Source: Dissertation Abstracts International, Volume: 46-10, Section: B, page: 3433. / Thesis (Ph.D.)--The Florida State University, 1985.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_75681 |
| Contributors | CACHERIS, WILLIAM PHILLIP., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 216 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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