P. A. Baisden

An automated, on-line rapid chemistry system

Abstract We have developed an automated chromatographic chemical element separation system (ACCESS) and an automated injection system (AIS) for rapid and reproducible ion-exchange separations of various chemical species. The system is modular to allow for many different separation configurations. Two high precision chromatography pumps, LDCs, provide constant solvent pressure throughout the system. An additional pump, and a six-way valve, permit the use of a total of up to eight different eluants in succession. The system is controlled by an IBM PC running a BASIC program. Chemical yield with the system has been determined to be 80±9%.

Development of High-Temperature Uv-Vis-Nir Spectroscopy for the Measurement of Free Energies of Complexation at Elevated Temperatures

We have developed instrumentation capable of measuring optical absorption spectra over a wavelength range of 200--1200 nm and a temperature range of 20--100{degree}C. This fiber-optic based spectrometer generates data which allow the computation of metal-ligand equilibrium constants. Studies at five temperatures have been completed using praseodymium-diglycolate as a model system. Fundamental thermodynamic values (free energies, enthalpies, entropies) were obtained from the experimentally-determined stability constants. Thermodynamic data pertinent to the interactions of actinides and long-lived fission products with groundwater, waste package components, and geologic media are critical input to modeling programs. 9 refs., 1 fig., 2 tabs.