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Thermodynamics of the complex formation of uranyl(VI) and thorium(IV) and some aromatic carboxylic acids
398
Conference
Abstracts
Thermodynamics of the Complex Formation of Uranyl(V1) and Thorium(IV) and Some Aromatic Carboxylic Acids BISMONDO Istituto
di Chimica
ARTURO
e Tecnologie Inorganiche e dei Materiali Avanzati, Corso Stati Uniti 4, 35020 Padova, Italy
Area di Ricerca
CNR,
A literature survey on the coordination chemistry between the actinide elements and aliphatic carboxylic acids in aqueous solution, reveals that the stoichiometries and the thermodynamic functions are well defined for a great number of ligands. Less attention has been given to the complexation of these cations with aromatic carboxylic acids. We intend to carry out a series of experiments on the interactions of uranyl(VI) and thorium(IV) ions with some mono- and bi-carboxylate ligands containing aromatic group(s) in the chain. Previous investigations concerned the complexing behaviour of phenylacetic acid relative to uranyl(VI): the thermodynamic function values for the I : 1 complex in aqueous solution and the structure of a solid compound of formula NaUO,L, have been reported. We report here on the thermodynamics of the thorium(IV)-phenylacetate system; the stability constant of the complex has been determined by potentiometry, the enthalpy change of formation by calorimetry. As in the previous study, this investigation was performed in 1.0 mol dmm3 aqueous solution of NaClO, at 25.O’C. The values obtained for the stability constant and for the enthalpy and entropy changes (log/I = 3.52; AH = I I.7 kJ mall’; AS = 107 J mall’ Km’) are discussed.
Effect of Ionizing Radiations on Microflora in Poultry Meat in Relation to Other Technological Variables* M. E. GUERZONI,’ ‘Dipartimento
M. A. CASADEI, B. ABDULLAH, P. G. FUOCHI and M. ADAM0
di Protezione
e Valorizzazione Via S. Giacomo
Agroalimentare, Universita 7, 40100 Bologna, Italy
G. MANFREDA, degli Studi
di Bologna,
This work is based on an experiment on deboned ground poultry meat packaged under vacuum and in ordinary atmosphere treated with five irradiation doses (0.5, I, 1.5, 2, 2.5 kGy). The effects of ionizing irradiation on the evolution of four microbial groups (Pseudomonads, Enterobacteriaceae, Gram negative bacteria and total psychotrophic bacteria) were evaluated by means of a comparison between the Gompertz equation parameters used to model the growth of the microbial groups. The aim was to find a suitable microbiological index for the identification of irradiated meat. The irradiation of the samples was performed using a I2 MeV Dickers linear electron beam accelerator. The dosimetry was performed by using the “Super Fricke” chemical dosimeter. All the samples were stored at 2°C. The comparison of the parameters of the growth curve revealed that the ratio between Pseudomonads and psychotrophic bacteria was the most reliable index for identifying irradiated meat. While in untreated samples the ratio was always >0.6, in the treated ones it did not exceed this value during the first week. Taking into account that irradiated poultry meat had a shelf-life lower than five days at 2C, the suggested index can be a useful tool for the identification of irradiated meat if compared with the production time.
*The research
has been performed
by the financial
support
ENEA
No. 644/90-O.
Conference
Abstracts
Thermodynamics of the Complex Formation of Uranyl(V1) and Thorium(IV) and Some Aromatic Carboxylic Acids BISMONDO Istituto
di Chimica
ARTURO
e Tecnologie Inorganiche e dei Materiali Avanzati, Corso Stati Uniti 4, 35020 Padova, Italy
Area di Ricerca
CNR,
A literature survey on the coordination chemistry between the actinide elements and aliphatic carboxylic acids in aqueous solution, reveals that the stoichiometries and the thermodynamic functions are well defined for a great number of ligands. Less attention has been given to the complexation of these cations with aromatic carboxylic acids. We intend to carry out a series of experiments on the interactions of uranyl(VI) and thorium(IV) ions with some mono- and bi-carboxylate ligands containing aromatic group(s) in the chain. Previous investigations concerned the complexing behaviour of phenylacetic acid relative to uranyl(VI): the thermodynamic function values for the I : 1 complex in aqueous solution and the structure of a solid compound of formula NaUO,L, have been reported. We report here on the thermodynamics of the thorium(IV)-phenylacetate system; the stability constant of the complex has been determined by potentiometry, the enthalpy change of formation by calorimetry. As in the previous study, this investigation was performed in 1.0 mol dmm3 aqueous solution of NaClO, at 25.O’C. The values obtained for the stability constant and for the enthalpy and entropy changes (log/I = 3.52; AH = I I.7 kJ mall’; AS = 107 J mall’ Km’) are discussed.
Effect of Ionizing Radiations on Microflora in Poultry Meat in Relation to Other Technological Variables* M. E. GUERZONI,’ ‘Dipartimento
M. A. CASADEI, B. ABDULLAH, P. G. FUOCHI and M. ADAM0
di Protezione
e Valorizzazione Via S. Giacomo
Agroalimentare, Universita 7, 40100 Bologna, Italy
G. MANFREDA, degli Studi
di Bologna,
This work is based on an experiment on deboned ground poultry meat packaged under vacuum and in ordinary atmosphere treated with five irradiation doses (0.5, I, 1.5, 2, 2.5 kGy). The effects of ionizing irradiation on the evolution of four microbial groups (Pseudomonads, Enterobacteriaceae, Gram negative bacteria and total psychotrophic bacteria) were evaluated by means of a comparison between the Gompertz equation parameters used to model the growth of the microbial groups. The aim was to find a suitable microbiological index for the identification of irradiated meat. The irradiation of the samples was performed using a I2 MeV Dickers linear electron beam accelerator. The dosimetry was performed by using the “Super Fricke” chemical dosimeter. All the samples were stored at 2°C. The comparison of the parameters of the growth curve revealed that the ratio between Pseudomonads and psychotrophic bacteria was the most reliable index for identifying irradiated meat. While in untreated samples the ratio was always >0.6, in the treated ones it did not exceed this value during the first week. Taking into account that irradiated poultry meat had a shelf-life lower than five days at 2C, the suggested index can be a useful tool for the identification of irradiated meat if compared with the production time.
*The research
has been performed
by the financial
support
ENEA
No. 644/90-O.