Development of an Aqueous Thermodynamic Model for the Tc(IV)-Na{sup +}-OH{sup -}-H{sub 2}O-Gluconate System Under Basic Conditions: Implications for HLW Pretreatment at the Hanford Site

Conference · Thu Sep 11 04:00:00 EDT 2003

OSTI ID:826359

Hess, Nancy J; Xia, Y X; Felmy, Andrew R

The solubility of TcO{sub 2} {center_dot} nH{sub 2}O(am) was measured over the pH range of 3 to 2M NaOH and in the absence and in the presence of 0.01 to 0.5 M gluconate. The presence of 0.01 M gluconate results in increased solution concentrations of reduced Tc species of nearly two orders of magnitude relative to measured Tc concentrations in the absence of gluconate throughout the pH range investigated. An aqueous thermodynamic model for the Tc(IV) - Na+ - OH- - H{sub 2}O - gluconate system is developed based on these solubility experiments, spectrophotometric measurements, and XRD data. These experimental results are compared to the Th(IV) - Na+ - OH- - NO{sub 3} - H{sub 2}O - gluconate system and the possible implications for pretreatment strategies of HLW at the Hanford Site is discussed.

• Research Organization: Pacific Northwest National Lab., Richland, WA (US)
• Sponsoring Organization: USDOE Office of Science (SC) (US)
• OSTI ID: 826359
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
SOLUBILITY
THERMODYNAMIC MODEL
X-RAY DIFFRACTION