Iodide Retention by Modified Kaolinite in the Context of Safe Disposal of High Level Nuclear Waste

Sivachidambaram, S and Sudhakar , Rao M (2012) Iodide Retention by Modified Kaolinite in the Context of Safe Disposal of High Level Nuclear Waste. In: JOURNAL OF HAZARDOUS, TOXIC, AND RADIOACTIVE WASTE © ASCE, 16 (3). pp. 192-200.

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Abstract

Bentonite clay is identified as potential buffer in deep geological repositories (DGR) that store high level radioactive wastes (HLW) as the expansive clay satisfies the expected mechanical and physicochemical functions of the buffer material. In the deep geological disposal of HLW, iodine-129 is one of the significant nuclides, attributable to its long half-life (half life 1⁄4 1:7 × 107 years). However, the negative charge on the basal surface of bentonite particles precludes retention of iodide anions. To render the bentonite effective in retaining hazardous iodide species in DGR, improvement of the anion retention capacity of bentonite becomes imperative. The iodide retention capac-ity of bentonite is improved by admixing 10 and 20% Ag-kaolinite (Ag-K) with bentonite (B) on a dry mass basis. The present study produced Ag-kaolinite by heating silver nitrate-kaolinite mixes at 400°C. Marginal release of iodide retained by Ag-kaolinite occurred under extreme acidic (pH 1⁄4 2:5) and alkaline (pH 1⁄4 12:5) conditions. The swell pressure and iodide etention results of the B-Ag-K specimens bring out that mixing Ag-K with bentonite does not chemically modify the expansive clay; the mixing is physical in nature and Ag-K presence only contributes to iodide retention of the admixture. DOI: 10.1061/(ASCE)HZ.2153-5515.0000121. © 2012 American Society of Civil Engineers.

Item Type:	Journal Article
Publication:	JOURNAL OF HAZARDOUS, TOXIC, AND RADIOACTIVE WASTE © ASCE
Publisher:	JOURNAL OF HAZARDOUS, TOXIC, AND RADIOACTIVE WASTE © ASCE
Additional Information:	copyright for this article belongs to the JOURNAL OF HAZARDOUS, TOXIC, AND RADIOACTIVE WASTE © ASCE
Department/Centre:	Division of Mechanical Sciences > Centre for Sustainable Technologies (formerly ASTRA) Division of Mechanical Sciences > Civil Engineering
Date Deposited:	20 Jun 2014 08:41
Last Modified:	20 Jun 2014 08:46
URI:	http://eprints.iisc.ac.in/id/eprint/49281

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