Document Detail


Performance of phosphoric acid activated montmorillonite as buffer materials for radioactive waste repository.
MedLine Citation:
PMID:  19747773     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In this study, the performance of phosphoric acid activated montmorillonite (PAmmt) was evaluated by cesium ions adsorption experiments. The PAmmt samples were obtained by activating with 1, 3 and 5 mol L(-1) of phosphoric acid, respectively under reflux for 3, 12, and 24h. Experimental results demonstrated that the treatment of raw K-10 montmorillonite with phosphoric acid increased the materials' affinity for Cs uptake and no significant amount of suspension solids were produced. A relatively insignificant variation in the CEC value was observed. Furthermore, PAmmt also showed high adsorption selectivity toward Cs ions. The improved sorptive properties were mainly related to the increased surface area and the relatively higher surface charge density. Increased specific surface area was the resulted from partial decomposition of lamellar structure of mmt; while the higher surface charge density was caused by the protonation of octahedral Al-OH sites during the acid activation. Generally speaking, stronger acid concentration and longer activation times would produce relatively more decomposed PAmmt particles. However, as the activation exceeds 3h, the precipitation of Si(4+) would passivate PAmmt against further acid attacks. Based upon our results, acid activation by phosphoric acid could produce PAmmt samples with high sorption capacity and selectivity, and good structural integrity, which are beneficial to be used at radioactive waste repository.
Authors:
Tsing-Hai Wang; Tsung-Ying Liu; Ding-Chiang Wu; Ming-Hsu Li; Jiann-Ruey Chen; Shi-Ping Teng
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-08-26
Journal Detail:
Title:  Journal of hazardous materials     Volume:  173     ISSN:  1873-3336     ISO Abbreviation:  J. Hazard. Mater.     Publication Date:  2010 Jan 
Date Detail:
Created Date:  2009-11-27     Completed Date:  2010-02-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9422688     Medline TA:  J Hazard Mater     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  335-42     Citation Subset:  IM    
Affiliation:
Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan.
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MeSH Terms
Descriptor/Qualifier:
Acids
Adsorption
Bentonite / chemistry*
Buffers
Cesium / chemistry
Fluorides / chemistry
Phosphoric Acids / chemistry*
Porosity
Radioactive Waste / analysis*
Refuse Disposal / methods*
Spectroscopy, Fourier Transform Infrared
Sulfates / chemistry
Surface Properties
Thermodynamics
X-Ray Diffraction
Chemical
Reg. No./Substance:
0/Acids; 0/Buffers; 0/Fluorides; 0/Phosphoric Acids; 0/Radioactive Waste; 0/Sulfates; 1302-78-9/Bentonite; 7440-46-2/Cesium

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