The presence of long-lived radionuclides in natural aquatic systems is of great environmental concern in view of their possible migration into biospheres of mankind. Trivalent actinides such as (241/243)Am can contribute a great deal to radioactivity for several thousand years. This migration is significantly influenced by various factors such as pH, complexing ions present in aquatic environme...

Silica sol, i.e., colloidal SiO2, may be used as a low-pH injection grout for very fine fractures in the construction of deep geological repositories for radioactive waste in Sweden and in Finland. If the bentonite barrier encounters SiO2-colloid particles under conditions favorable for aggregation, there is concern that it will modify the bentonite barrier at the bentonite/bedrock interface. I...

Bentonites are widely used for waste repository systems because of their hydrodynamic, surface and chemical-retention properties. MX 80 bentonite (bentonite of Wyoming) contains approximately 85% Na/Ca-montmorillonite and 15% accessory minerals. The dominant presence of Na/Ca-montmorillonite in this clay mineral could cause it to perform exceptionally well as an engineered barrier for a radioac...

Bentonite modified with ferrocyanides of Fe, Cu and CuK was tested for sorption of Cs137 and Sr-90 and proved to be highly selective for Cs; ferrocyanides of Cu and CuK are also good sorbents for Sr. Bentonite modified with hydroxides of Ti, Sn and Sb are good for Sr removal.

The adverse effect of mineral dust on general health level of the population has been widely studied lately. The research interest has been mainly focused on the respiratory function of coal miners and workers exposed to silica and asbestos containing dust [1-3] because a significant increase in COPD independent of smoking has been observed [4-5]. Among the materials considered hazardous for wo...

This paper presents the effect of sisal fibers on the unconfined compressive strength of bentonite. The present study is aimed at determining the behavior of bentonite-lime-phosphogypsum reinforced with sisal fibers in a random manner. The sisal fiber content was varied from 0.5 to 2 %. The results indicated that the unconfined compressive strength of bentonite can be increased by the addition ...

Johnson, H. M. (Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio), K. Brenner, R. Angelotti, and H. E. Hall. Serological studies of types A, B, and E botulinal toxins by passive hemagglutination and bentonite flocculation. J. Bacteriol. 91:967-974. 1966.-Formalinized sheep red blood cells (SRBC), sensitized with types A, B, and E botulinal toxoids and toxins by bis-diazotized benzid...

Cement bentonite interactions need to be studied since they will occur in deep geological repositories.They are specifically relevant in the clay host rock reference concept. The reactivity of a Mg-homoionicFEBEX bentonite was studied at 60 oC in contact with a young cement water characterized by the leachingof alkaline hydroxides (K/Na 4/1 –OH, pH = 13.5 at 25 oC) and with an e...

One of the requirements of a system for disposal of spent nuclear fuel is that it should be possible and feasible to retrieve the canisters even after they have been put in place and the surrounding bentonite has absorbed water and developed a swelling pressure. This ‘gripping’ of the canister must be released before the canister can be retracted from the deposition hole. One way to achieve thi...