Authors:S. Marsh, G. Jarvinen, R. Bartsch, J. Nam, and M. Barr
Additional1 bifunctional anion-exchange resins have been designed, synthesized and evaluated for their ability to take up Pu(IV) from
nitric acid solutions. Bifunctionality is achieved by adding a second anion-exchange site to the pyridine nitrogen (also an
anion-exchange site) of the base poly(4-vinylpyridine) resin. Previous work focused on the effect of varying the chemical
properties of the added site along with the length of an alkylene ‘spacer’ between the two sites. Here we examine four new
3- and 4-picolyl derivatives which maintain more rigidly defined geometries between the two nitrogen cationic sites. These
materials, which have the two anion-exchange sites separated by three and four carbons, respectively, exhibit lower overall
Pu(IV) distribution coefficients than the corresponding N-alkylenepyridium derivatieves with more flexible spacers. Methylation
of the second pyridium site results in a ca. 20% increase in the Pu(IV) distribution coefficients.
The use of titanium oxide as a photocatalyst in the degradation of organic complexing agents by ultraviolet radiation is being studied as a possible method for the removal of radioactive ions from solutions of these complexing agents that have been used to decontaminate nuclear facilities. Inorganic absorbers are being increasingly used for the decontamination of radioactive aqueous wastes. Information is presented on two areas of study to incorporate inorganic absorbers into a matrix material in order to provide a granular product suitable for use in a packed bed. Finally, information is reported on the combination of inorganic absorbers with magnetite in order to allow separation of the loaded absorber from the treated liquid waste by use of a magnet.
Authors:G. Müller, M. Navarrete, T. Martínez, and L. Cabrera
Nuclear chemistry is usually associated with great disasters, especially the atomic bomb; this without reflecting that knowledge
of nuclear chemistry has also had many benefits in the field of medicine and health. Whereas in technologically advanced countries,
nuclear chemistry is considered to be an important part of the syllabus, including topics such as radioactivity with the emphasis
in making conscience in the common citizen of the inherent benefits.
The influence of radioactive krypton85Kr on the surface properties of poly(3-pentylthiophene) has been studied. Irradiation by gaseous85Kr leads to structural polymeric chain changes, which induce after iodine doping the formation of charge-transfer complexes with iodine as well as with gaseous sulfur dioxide manifesting itself by the increased electric conductivity. The presence of ammonia brings about reaction with iodine bound in the complex with a conducting polymer.
The importance of the thermal behaviour of glasses is illustrated. Some procedural characteristics for glass preparation upon quenching are discussed to distinguish the positive effects of increasing cooling rate. The basic thermodynamic quantities, kinetic data and procedural parameters are listed. The glass-transformation interval is treated in detail to demonstrate the temperature-dependences of heat capacity, enthalpy an Gibbs energy for as-quenched and annealed glasses, exemplifying processes of thermally stimulated reordering. Particular attention is paid to DTA measurements, which are of use for the determination of characteristic temperatures and to for the distinction of possible types of processes which occur upon reheating. Most common cases are illustrated by a series of hypothetical ΔH vs. T and ΔTdtavs. T plots. Different glass formation coefficients based on the onset temperatures are discussed to confirm the general knowledge that their maxima match with concentration regions close to that of invariant melting of the system.
Bone provides an important source of forensic evidence. The storage conditions of bone have been recognised as a factor in
maintaining the integrity of such evidence. Thermogravimetric analysis (TG) has been employed to examine the effects of storage
environments and preparation methods on the structural properties of pig bones. A comparison of oven and freeze drying has
been made to study the effect of storage conditions. A comparison has also been made of ground bone specimens with cut specimens.
Freeze-dried hand ground specimens provided the most consistent results and, thus, this is the recommended method of preparation
of bone specimens for TG analysis.
Separate stages of mathematical processing of thermogravimetric data, the difficulties most often encountered, and typical error sources are considered. A complex procedure of automatic acquisition and editing of experimental data, including calculation of effective kinetic parameters, is described and an appropriate algorithm for the 15 BCM-5 microcomputer is presented. The computer calculation of the kinetic parameters of the multistage thermal decomposition of a polyamide fibre is given as an example.