Organic tanks safety program, FY97 waste aging studies. Revision 1

Camaioni, D.M.; Samuels, William D.; Linehan, John C.; Sharma, Anubha; Hogan, M.O.; Lilga,; Clauss, S.A.; Wahl, Karen L.; Campbell, J.A.

doi:10.2172/650142

Cited by 9 publications

(35 citation statements)

References 13 publications

(24 reference statements)

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“…Tank waste and solubility studies have shown that the results are dependent on tank waste type. In other words, for tanks with different fill histories, the dominant organic anions in the waste may be primarily glycolate, primarily acetate, or a combination of both anions , Camaioni et al, 1998, Barney 1997, Ashby et al, 1994 For C-104 analyses, no acetate/glycolate peak was detected in the supernatants or solids above the MDL. In view of the fact that acetate and glycolate have similar response factors, the reported acetate MDL can be used to bound the upper acetate/glycolate concentration.…”

Section: Analysis Resultsmentioning

confidence: 99%

Organic Analysis of C-104 Tank Waste

Evans¹,

Campbell²,

Hoopes³

et al. 2001

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Section: Analysis Resultsmentioning

confidence: 99%

Organic Analysis of C-104 Tank Waste

Evans¹,

Campbell²,

Hoopes³

et al. 2001

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“…The thermal and radiolytic oxidation of organic compounds in simulated Hanford wastes have been studied extensively (Ashby et al 1992(Ashby et al , 1993(Ashby et al ,1994Barefield et al 1995Barefield et al , 1996Bryan et al 1993;Bryan and Pederson 1994;Camaioni et al 1995Camaioni et al ,1996Camaioni et al ,1997Delegard 1980Delegard ,1987Meisel et al 1991aMeisel et al , 1991bMeisel et al , 1992Meisel et al , 1993Meisel et al , 1997. The reactivity order for thermal degradation of the complexants, which encompasses all the pathways for the decomposition of the organic constituents in the waste in the absence of radiation, has been given as (Camaioni et al 1996):…”

Section: General Features Of Organic Reactions In Hanford Wastesmentioning

confidence: 99%

“…Additional radiolytic pathways are available for the aging of complexants and solvents in Hanford wastes (Meisel et al 1991a(Meisel et al , 1991b(Meisel et al , 1992(Meisel et al , 1993(Meisel et al ,1997Camaioni et al 1995Camaioni et al , 1996Camaioni et al , 1997. Products of water radiolysis include the hydrated electron, hydrogen atom, hydroxide radical, hydrogen dioxide radical, and hydrogen ion (Spinks and Woods 1990).…”

Section: General Features Of Organic Reactions In Hanford Wastesmentioning

confidence: 99%

“…The products that are designated in bold face have been detected in tank waste (Campbell et al 1994(Campbell et al ,1995(Campbell et al ,1996. Glycine has been shown to be a reaction product in laboratory work (Ashby et al 1994;Barefield et al 1995;Camaioni et al 1996Camaioni et al , 1997.…”

Section: Pathways To Aged Oxidized Organic Compoundsmentioning

confidence: 99%

“…[ 1994,1995,19961) Hydrolysis reactions are also important in Hanford wastes. The amides and nitriles formed from fragmentation of complexants are hydrolyzed under the conditions of storage (Ashby et al 1993(Ashby et al ,1994Barefield et al 1995Barefield et al ,1996Camaioni et al 1997). Acetals and the analogous nitrogenous derivatives formed as intiermediates on several reaction pathways are also susceptible to hydrolysis.…”

Section: Pathways To Aged Oxidized Organic Compoundsmentioning

confidence: 99%

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Chemical pathways for the formation of ammonia in Hanford wastes

Stock¹,

Pederson²

1997

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This report reviews chemical reactions leading to the formation of ammonia in Hanford wastes. The general features of the chemistry of the organic compounds in the Hanford wastes are briefly outlined. The radiolytic and thermal free radical reactions that are responsible for the initiation and propagation of the oxidative degradation reactions of the nitrogen-containing complexants, trisodium HEDTA and tetrasodium EDTA, are outlined. In addition, the roles played by three different ionic reaction pathways for the oxidation of the same compounds and their degradation products are described as a prelude to the discussion of the formation of ammonia. The reaction pathways postulated for its formation are based on tank observations, laboratory studies with simulated and actual wastes, and the review of the scientific literature. Ammonia derives from the reduction of nitrite ion (most important), from the conversion of organic nitrogen in the complexants and their degradation products, and from radiolytic reactions of nitrous oxide and nitrogen (least important).Reduction of nitrite ions is believed to be the most important source of ammonia. Whether by radiolytic or thermal routes, nitrite reduction reactions proceed through nitrogen dioxide, nitric oxide, the nitrosyl anion, and the hyponitrite anion. Nitrite ion is also converted into hydroxylamine, another important intermediate on the pathway to form ammonia. These reaction pathways additionally result in the formation of nitrous oxide and molecular nitrogen, whereas hydrogen formation is produced in a separate reaction sequence.The oxidative degradation of trisodium EDTA and tetrasodium HEDTA also yields ammonia and other nitrogenous gases. The complexants react with nitric oxide and nitrogen dioxide to produce oxidized compounds that subsequently undergo hydrolysis, eventually liberating ammonia. Amides and nitriles are intermediates in these long reaction sequences. , The direct reaction of hydrogen with nitrous oxide and nitrogen can account for only negligible quantities of ammonia in Hanford tanks. Thermal reactions require high temperatures (AOOOC), high pressures, and the presence of catalysts, to proceed at significant rates. Similarly, radiolytic yields for direct reactions of hydrogen with nitrogen and nitrous oxide under tank conditions are expected to be very small.Oxygen can substantially alter the yields of nitrogenous gases. Two principal pathways have been identified. Oxygen intercepts radicals produced in thermal and radiolytic reactions that would otherwise eventually result in the formation of nitrogen, nitrous oxide and ammonia. Oxygen also reacts directly with complexants and intermediates to yield oxalate ion. The hydrogen yield is often increased in the presence of oxygen.

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Identification of Radicals and Determination of Their Yields in the Radiolytic Oxidation of Glycine. Time-resolved ESR Methodology

Hug

Fessenden

2000

J. Phys. Chem. A

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Both aminomethyl (•CH2NH2) and H2N−•CH−CO2 - radicals were identified by time-resolved ESR spectroscopy in the oxidation of glycine anions by •OH. Previous ESR measurements had detected only the H2N−•CH−CO2 - radical in these systems. The rise times of the ESR lines for these two different radicals are consistent with both of the radicals being formed in the initial reaction of •OH with the glycine anions. The yields of these two C-centered radicals relative to the total yield of •OH are approximately 29% for aminomethyl radicals and 53% for H2N−•CH−CO2 - radicals. The yield of aminomethyl radicals from methlyamine was 53%. No ESR lines attributable to aminyl radicals could be directly detected in solutions of glycine (HN•−CH2−CO2 -) at high pH or low pH, or in solutions of methylamine (HN•−CH3). However, clear evidence for the presence of the aminyl radicals was obtained in spin-trapping experiments using the aci-anion form of nitromethane with both methylamine and glycine. The rapid appearance of aminomethyl radicals in a complementary experiment with hydrated electrons reacting with N-chloroglycine could be simply explained on the basis of the formation of N-centered radicals in this situation. The ESR method for determining the yields was tested in the •OH oxidation of methylamine and succinic acid. The implications of the findings of this work are discussed in the context of the recently proposed scheme for the oxidation of glycine anions by •OH.

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Organic tanks safety program, FY97 waste aging studies. Revision 1

Cited by 9 publications

References 13 publications

Organic Analysis of C-104 Tank Waste

Organic Analysis of C-104 Tank Waste

Chemical pathways for the formation of ammonia in Hanford wastes

Identification of Radicals and Determination of Their Yields in the Radiolytic Oxidation of Glycine. Time-resolved ESR Methodology

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