Registro:
| Documento: | Tesis Doctoral |
| Disciplina: | quimica |
| Título: | Estado químico del arsénico formado por transformaciones nucleares en compuestos inorgánicos de germanio, selenio, bromo y arsénico |
| Autor: | Baró, Gregorio Bonifacio |
| Editor: | Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales |
| Lugar de trabajo: | Instituto de Investigaciones Nucleares de Amsterdam (Instituut voor Kernphysisch Onderzoek)
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| Publicación en la Web: | 2017-03-01 |
| Fecha de defensa: | 1961 |
| Fecha en portada: | 1961 |
| Grado Obtenido: | Doctorado |
| Título Obtenido: | Doctor en Ciencias Químicas |
| Departamento Docente: | Departamento de Química (hasta 1976) |
| Director: | Aten Junior, Adrián H. W. |
| Idioma: | Español |
| Formato: | PDF |
| Handle: |
http://hdl.handle.net/20.500.12110/tesis_n1096_Baro |
| PDF: | https://bibliotecadigital.exactas.uba.ar/download/tesis/tesis_n1096_Baro.pdf |
| Registro: | https://bibliotecadigital.exactas.uba.ar/collection/tesis/document/tesis_n1096_Baro |
| Ubicación: | 001096 |
| Derechos de Acceso: | Esta obra puede ser leída, grabada y utilizada con fines de estudio, investigación y docencia. Es necesario el reconocimiento de autoría mediante la cita correspondiente. Baró, Gregorio Bonifacio. (1961). Estado químico del arsénico formado por transformaciones nucleares en compuestos inorgánicos de germanio, selenio, bromo y arsénico. (Tesis Doctoral. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales). Recuperado de http://hdl.handle.net/20.500.12110/tesis_n1096_Baro |
Abstract:
The distribution of radioactive arsenic among trivalentand pentavalent states of arsenic produced by nuclear transformations has been investigated in simple inorganic compounds of germanium, selenium, bromine and arsenic. In some cases we have studied the change of this distribution by annealing processes. The nuclear transformations we have studied are the following: Ge77-—β—> As77 Se76 (n,p) As76 Br81 (n,α) As78 Br79 (n,α) As76 As75 (n,γ) As76. The compounds were irradiated with neutrons in the RAI reactor in Buenos Aires and later with neutrons obtained bybombarding beryllium with 26 MeV deuterons in the Philipssynchrocyclotron of Amsterdam. The chemical separations used consisted of the dissolution of the irradiated compound in a solution containing AsIIIand AsV carriers. The arsenate fractions were separated from the arsenite fractions by precipitation as magnesium ammonium arsenate. The arsenite was then oxidized to arsenate which in turn was precipitated as magnesium ammonium arsenate. All fractions were converted to magnesium piro-arsenate. The radioactive samples were counted with an end-window G.M. counter under conditions of standard geometry. Annealing was carried out in constant-temperature bathsduring specified periods of time. It is evident from our experimental results that chemical conditions in the aqueous medium, and specially the pH, have little or no influence on the distribution of the arsenic activity among the two oxidation states. This suggests that the final form in which the radioactive arsenic will be foundis already determined inside the target lattice. It is even more striking that the distribution observedin GeO2 is very nearly equal to that in SeO2. This suggests that the structure of the oxide is the determining factor for the distribution of the arsenic activity among arsenite and arsenate fractions. It is very curious that the AsV: total As of radioactive arsenic in the oxides of germanium and selenium and in the oxides of arsenic may be represented asa linear function of the oxygen: parent element ratio for the irradiated compound. This is true for some other compoundsas Na2Se04 and Na2Ge03. In the other compounds that we have investigated the linear relationship does not hold very well. In part this maybe the reflection of the differences in the lattice arrangement, but reducing and oxidizing tendencies of the irradiated compounds may also possibly play a role. The differences found between Na2Se03 and H2Se03 can be ascribedto bound hydrogen present inside the latter compound. The results in the bromine compounds indicate that the distribution of radioactive arsenic among the arsenite andarsenate fractions depends on the amount of oxygen containedin the irradiated compounds. Even in the bromides the percentageof radioarsenic is fairly directly correlated with the oxygen present as water in the crystal. Annealing turned out to be quite slow, even at temperatures appreciably higher than those required to increase the retention in most neutron irradiated solid salts. The first part of this thesis presents a survey of the field of Szilard-Chalmers and similar phenomena with emphasison inorganic systems. It will not cite all the literature published until now, but will try to review some of the most significant recent work.
Citación:
---------- APA ----------
Baró, Gregorio Bonifacio. (1961). Estado químico del arsénico formado por transformaciones nucleares en compuestos inorgánicos de germanio, selenio, bromo y arsénico. (Tesis Doctoral. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales.). Recuperado de https://hdl.handle.net/20.500.12110/tesis_n1096_Baro
---------- CHICAGO ----------
Baró, Gregorio Bonifacio. "Estado químico del arsénico formado por transformaciones nucleares en compuestos inorgánicos de germanio, selenio, bromo y arsénico". Tesis Doctoral, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, 1961.https://hdl.handle.net/20.500.12110/tesis_n1096_Baro
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https://bibliotecadigital.exactas.uba.ar/download/tesis/tesis_n1096_Baro.pdf
