Adsorption of ^133Cs and ^87Sr on pumice tuff：A comparative study between powder and intact solid phase

• Published in: Acta geochimica 2017-06, Vol.36 (2), p.224-231
• Main Authors: Rajib, Mohammad, Oguchi, Chiaki T.
• Format: Article
• Language: English
• Subjects: Adsorption; Caesium isotopes; Cesium; Cesium 133; Comparative analysis; Comparative studies; Destruction; Earth and Environmental Science; Earth Sciences; Geochemistry; Intrusion; Measurement; Mercury; Original Article; Phase transitions; Pore size; Pore size distribution; Pores; Porosity; Porous materials; Powder; Pumice; Rocks; Size distribution; Solids; Sorption; Strontium; Strontium isotopes; Surface area; Surface chemistry; Tuff; Volcanoes; 凝灰岩; 分配系数; 化学条件; 吸附系数; 固相; 浮石; 灰岩样品; 野外条件
• ISSN: 2096-0956; 2365-7499
• DOI: 10.1007/s11631-016-0133-3

This study examines the use of intact samples as an alternative to powder in conventional batch sorption studies to determine the distribution coefficient（Kd）.Stable cesium（^133Cs） and strontium（^87Sr） were used under specified geochemical conditions to compare the Kdvalues of powder and block pumice tuff samples. The aim of the study was to infer any Kddifference under laboratory and field conditions. Kdvalues for block samples were found to be less than one order of magnitude lower than powder materials for both Cs and Sr on fresh tuff, and more than one order of magnitude lower in oxidized tuff. Destruction of micropores in oxidized tuff was estimated to be mainly responsible for reducing Kdvalues in oxidized tuff. However, approximately one order of magnitude difference in Kdvalues indicates that homogenously prepared intact samples can be used for sorption coefficient measurement at closer to in situ conditions. Pore size distribution analysis using mercury intrusion porosimetry revealed that lower Kdvalues on block samples result from lower surface area available as sorption sites due to inaccessible closed pores in the intact solid.