Affiliation:
1. Department of Chemistry , Rani Channamma University , Belagavi 591156 , India
2. Radioanalytical Chemistry Division, Bhabha Atomic Research Centre , Mumbai 400085 , India
3. Homi Bhabha National Institute, Anushaktinagar , Mumbai 400094 , India
Abstract
Abstract
Bentonite is the candidate buffer and backfill material in the deep geological repositories. Montmorillonite (Mt) is the major clay minerals of bentonite. Over a long period of time, the interaction of corrosion products from overpack and/or cansister with clay minerals is expected to result in formation of Fe(III)-Mt, a plausible alterated product. In this context, it is important to understand the properties of Fe-Mt in comparison with original clay mineral, Na-Mt. In the present study, sorption behavior of Cs(I), long lived fission product (135Cs, t1/2 = 2.3 × 106 years; 137Cs, t1/2 = 30.1 years) with high fission yield, on Fe(III)-Mt is investigated. Batch sorption studies are conducted at varying pH (3–9), ionic strength (0.001–1 M) and Cs(I) concentration (10−10 to 0.05 M). The distribution coefficient (Kd) of Cs(I) on Fe(III)-Mt was found to be independent of pH except at low pH, indicating ion exchange mechanism as dominant interaction mode for Cs(I). It was further verified by ionic strength variation which depicted decrease in Cs(I) sorption with increasing ionic strength. Adsorption isotherm of Cs(I) was found to be linear over the concentration range of 10−10 to 10−3 M Cs(I). The Fe released from Fe(III)-Mt during the Cs(I) sorption was found to be not more than 0.2 ppm. However, on lowering the pH and increasing the ionic strength, the Fe release increased. Furthermore, the apparent diffusion coefficient for Cs(I) in Fe(III)-Mt has been determined.
Subject
Physical and Theoretical Chemistry
Reference57 articles.
1. Pusch, R.: Waste disposal in rock developments in geotechnical engineering, Vol. 76. Elsevier, New York (1994).
2. Fernandez, A. M., Villar, M. V.: Geochemical behavior of a bentonite barrier in the laboratory after up to 8 years of heating and hydration. Appl. Geochem. 25, 809 (2010).10.1016/j.apgeochem.2010.03.001
3. Karnland, O., Olsson, S., Nilsson, U.: Mineralogy and sealing properties of various bentonites and smectite-rich clay materials. In: SKB TR-06-30. Swedish Nuclear Fuel and Waste Management Co, Stockholm, Sweden (2006).
4. Komine, H.: Simplified evaluation for swelling characteristics of bentonites. Eng. Geol. 71, 265 (2004).10.1016/S0013-7952(03)00140-6
5. Kozai, N., Ohnuki, T., Matsumoto, J., Banba, T., Ito, Y.: A study of specific sorption of neptunium (V) on smectite in low pH solution. Radiochim. Acta 75, 149 (1996).
Cited by
11 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献