TESTING AND CHARACTERIZATION OF ENGINEERED FORMS OF MONOSODIUM TITANATE (MST)

Taylor-Pashow, K. ; Nash, C. ; Hobbs, D.

Savannah River Site (S.C.)

关键词: Removal;    Gelation;    Testing;    Capacity;    Liquid Wastes;   

DOI  :  10.2172/1043254
RP-ID  :  SRNL-STI-2012-00193
RP-ID  :  DE-AC09-08SR22470
RP-ID  :  1043254

美国|英语

来源: UNT Digital Library

【 摘 要 】

Engineered forms of MST and mMST were prepared at ORNL using an internal gelation process. Samples of these two materials were characterized at SRNL to examine particle size and morphology, peroxide content, tapped densities, and Na, Ti, and C content. Batch contact tests were also performed to examine the performance of the materials. The {sup E}mMST material was found to contain less than 10% of the peroxide found in a freshly prepared batch of mMST. This was also evidenced in batch contact testing with both simulated and actual waste, where little difference in performance was seen between the two engineered materials, {sup E}MST and {sup E}mMST. Based on these results, attempts were made to increase the peroxide content of the materials by post-treatment with hydrogen peroxide. The peroxide treatment resulted in a slight ({approx}10%) increase in peroxide content; however, the peroxide:Ti molar ratio was still much lower ({approx}0.1 X) than what is seen in a freshly prepared batch of mMST. Testing with simulated waste showed the performance of the peroxide treated materials was improved. Batch contact tests were also performed with an earlier (2003) prepared lot of {sup E}MST to examine the effect of ionic strength on the performance of the material. In general the results showed a decrease in removal performance with increasing ionic strength, which is consistent with previous testing with MST. A Sr loading isotherm was also determined, and the {sup E}MST material was found to reach a Sr loading as high as 13.2 wt % after 100 days of contact at a phase ratio of 20000 mL/g. At the typical MST phase ratio of 2500 mL/g (0.4 g/L), a Sr loading of 2.64 wt % was reached after 506 hours of contact. Samples of {sup E}MST and the post-peroxide treated {sup E}mMST were also tested in a column configuration using simulated waste solution. The breakthrough curves along with analysis of the sorbent beds at the conclusion of the experiments showed that the peroxide treated {sup E}mMST has a higher Sr and Np capacity, but that both materials have similar Pu capacities. The {sup E}MST removed a larger percentage of U than the peroxide treated {sup E}mMST, which is consistent with previous testing which showed that mMST has little affinity for U under these conditions.