TITLE:
Oxidation of Solid Phase and Ionic Strength Effect to the Cesium Adsorption on Pumice Tuff
AUTHORS:
Mohammad Rajib, Taishi Kobayashi, Chiaki T. Oguchi, Takayuki Sasaki
KEYWORDS:
Oxidation, Ionic Strength, Adsorption, Cesium, Batch Experiment, Distribution Coefficient, Pumice Tuff
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.4 No.2,
February
22,
2016
ABSTRACT: In-situ oxidation of solid phase was considered to investigate adsorption
behavior under different geochemical parameters like pH, initial concentration
and ionic strength. Pumice tuff, a potential host rock for low and intermediate
radioactive wastes, has been affected by the redox zone. The characterization
of the fresh and oxidized tuff was performed by X-ray diffractometer, scanning
electron microscope and mercury intrusion porosimetry. In order to compare the
difference of distribution coefficient (Kd)
in fresh and oxidized pumice tuffs, a batch adsorption study was carried out at
the range of pH (4 - 12), ionic strength (0.003, 0.1, 1.0 and 3.0 mol/dm3)
and initial cesium concentration (10dž, 10LJ, 10Lj and 10lj mol/dm3). Based on experimental Kd values, ionic strength was
found to be the most influential factor, whereas the effects of pH, initial Cs
concentration and weathering condition
of pumice tuff were negligible. The recalculated Kd values suggest that the existing surface complexation
model is applicable to explain the sorption coefficients through the wide range
of solution conditions.