Adsorption Studies of Radioactive Cobalt on a Minerals Mixture

Ahmad, Shujaat; Mannan, Abdul; Qureshi, I. H.

doi:10.1080/01496399208018898

Cited by 6 publications

(2 citation statements)

References 16 publications

(7 reference statements)

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“…Many different processes have been investigated for removing these species from aqueous solutions. − They vary from traditional methods such as precipitation, extraction, ion exchange, and adsorption to relatively less conventional or new ones such as bioaccumulation 23-25 and electric-field-assisted techniques . Among the inorganic ion-exchange resins and adsorbents investigated for removing these metals, natural and synthetic zeolites, , titanites, ,, silica, silicotitanites, − and silica- or chabazite-supported metal hexacyanoferrates 15-19 are the most common.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Cesium, Strontium, and Cobalt Ions on Magnetite and a Magnetite−Silica Composite

Ebner

Ritter

Navratil

2001

Ind. Eng. Chem. Res.

129

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Constant pH adsorption isotherms for nonradioactive Cs + , Sr 2+ , and Co 2+ on pure magnetite and a 80% (w/w) magnetite-silica composite were measured at 25 °C over a wide range of metal ion concentrations. The adsorption studies were carried out at four different pH's: 6, 7, 8, and 9 for Cs + and Sr 2+ and 5, 6, 7, and 8 for Co 2+ . All of the constant pH isotherms exhibited type I behavior with a saturation capacity that was pH-dependent and increased with increasing pH. The corresponding distribution coefficients increased with increasing pH but decreased with increasing metal ion concentration; they were also 10-1000 times lower than those reported in the literature for more selective but more expensive adsorbents. These two magnetite-based adsorbents also exhibited moderate regeneration conditions, with nearly 90-100% regeneration achieved in most cases at pH values between 1 and 3. A Langmuir model with pH-dependent parameters was also fitted successfully to all of the constant pH adsorption isotherms. This experimental data and the corresponding pH-dependent Langmuir correlation should find considerable use in the design and development of inexpensive fixed-bed adsorption processes for the removal of the radioactive isotopes of Cs + , Sr 2+ , and Co 2+ from aqueous solutions that are produced in nuclear facilities. Magnetite, when encased in silica and placed in a packed column, can also be used as the charging element in high gradient magnetic separation, thereby removing not only metal ions via surface complexation (adsorption) but also nanoparticles of a paramagnetic nature.

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Section: Introductionmentioning

confidence: 99%

Adsorption of Cesium, Strontium, and Cobalt Ions on Magnetite and a Magnetite−Silica Composite

Ebner

Ritter

Navratil

2001

Ind. Eng. Chem. Res.

129

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“…Therefore, separation of iron and cobalt from the decontamination waste is difficult. Another method (7) has been reported which makes use of mineral mixtures in the separation of cobalt. About 80% removal of cobalt has been reported for a contact time of 2 minutes.…”

Section: Introductionmentioning

confidence: 98%

Separation of Cobalt from Synthetic Intermediate and Decontamination Radioactive Wastes Using Polyurethane Foam

Rao

Lal

Narasimhan³

et al. 1997

Separation Science and Technology

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Studies have been carried out on the removal of radioactive cobalt (60Co) from synthetic intermediate level waste (ILW) and decontamination waste using neat polyurethane (PU) foam as well as n-tributyl phosphate-polyurethane (TBP-PU) foam. The radioactive cobalt has been extracted on the PU foam as cobalt thiocyanate from the ILW. Maximum removal of cobalt has been observed when the concentration of thiocyanate in the solution is about 0.4 M. Cobalt can be separated from decontamination waste containing ethylenediaminetetraacetic acid (EDTA) and iron(I1). The extent of extraction of cobalt is slow and the separation of iron and cobalt is better with the neat PU foam compared to the TBP-PU foam. The presence of iron in the decontamination waste facilitates the extraction of cobalt thiocyanate on the PU foam. Column studies have been carried out in order to extend these studies to the plant scale. The capacities of the PU foams for cobalt have been determined. The effect of density and the surface area of PU foam have been investigated. Fourier Transform Infrared (FT-IR) spectral studies have been conducted to find out the interaction between PU foam and cobalt thiocyanate species.

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