The Identification and Degradation of Isosaccharinic Acid, a Cellulose Degradation Product

1994 ◽  
Vol 353 ◽  
Author(s):  
B. F. Greenfield ◽  
G. J. Holtom ◽  
M. H. Hurdus ◽  
N. O’Kelly ◽  
N.J. Pilkington ◽  
...  
Keyword(s):  
High Performance ◽  
Degradation Products ◽  
Cellulose Degradation ◽  
Near Field ◽  
Experimental Studies ◽  
Water Soluble ◽  
Chemical Degradation ◽  
Alkaline Conditions ◽  
Isosaccharinic Acid ◽  
Microbial Action

AbstractNirex is seeking to develop a deep underground repository for the disposal of solid intermediate-level and low-level radioactive wastes (ILW and LLW) in the UK. One possible influence on the behaviour of radionuclides is the formation of water-soluble complexants by the degradation of the solid organic polymers that will be present in the wastes. The degradation products of cellulose have been shown to increase the solubility of plutonium and other radionuclides and to reduce sorption onto near-field and far-field materials. Degradation of cellulose under anaerobic alkaline conditions produces a range of organic acids. In this paper 2-C-(hydroxymethyl)-3-deoxy-D-pentonic acid (isosaccharinic acid, ISA) is identified by High Performance Liquid Chromatography as a significant component of cellulose leachates. A combination of fractionation of cellulose leachates and plutonium solubility determinations shows that ISA is responsible for the majority of the enhancement of plutonium solubility observed in such leachates. Further degradation of ISA by chemical or microbial action may lessen the effect of degraded cellulose leachates. Experimental studies on the chemical degradation of this compound under alkaline conditions suggest that the presence of oxygen is required. Microbial degradation studies show that the plutonium solubility in solutions of ISA is reduced by their exposure to microbial action.

The Effect of Cellulose Degradation Products on the Solubility and Sorption of Pu and Am in Alkaline-Plume-Affected and in Unaffected Boom Clay

2003 ◽  
Vol 807 ◽  
Author(s):  
F. Rorif ◽  
E. Valcke ◽  
M. A. Glaus
Keyword(s):  
Radioactive Waste ◽  
Water Sorption ◽  
Degradation Products ◽  
Cellulose Degradation ◽  
Potential Effect ◽  
Water Soluble ◽  
Boom Clay ◽  
Effect Of Water ◽  
Isosaccharinic Acid

ABSTRACTThe potential effect of water-soluble degradation products (DPs) formed from cellulose-containing cemented radioactive waste on the behaviour of Pu(IV) and Am(III) in Alkaline-Plume-Affected (APA) and in unaffected Boom clay was assessed. After solubility measurements in APA Real Clay Water, sorption experiments of Pu(IV) and Am(III) onto APA Boom clay were performed in the presence or not of DPs or pure α-isosaccharinic acid (α-ISA). Moreover, the sorption of α-ISA onto the unaffected clay was studied.

The Degradation of Cellulose in the Near Field of a Radioactive Waste Repository

1993 ◽  
Vol 333 ◽  
Author(s):  
B.F. Greenfield ◽  
M.H. Hurdus ◽  
N.J. Pilkington ◽  
M.W. Spindler ◽  
S.J. Williams
Keyword(s):  
Degradation Products ◽  
Cellulose Degradation ◽  
Near Field ◽  
Research Programme ◽  
Water Soluble ◽  
Anaerobic Conditions ◽  
Factors Affecting ◽  
Deep Underground ◽  
The Uk ◽  
Assessment Research

ABSTRACTUK Nirex Ltd is seeking to develop a deep underground repository for the disposal of solid low- and intermediate-level radioactive wastes in the UK. The Nirex Safety Assessment Research Programme (NSARP) comprises scientific research to support the post-closure performance assessment of the repository. One of the investigations carried out by AEA Technology under the NSARP is the investigation of the formation of water-soluble complexants from the degradation of the solid organic polymers and cellulosic materials present in such wastes. The influence of these complexants on the solubility and sorption of a number of radionuclides is also being investigated by a combination of experimental measurements and thermodynamic modelling. Under the alkaline, anaerobic conditions representative of the near field of the repository, cellulose has previously been shown to degrade to yield soluble products which enhance the solubilities and reduce the sorption of several radionuclides. As part of this investigation, cellulose was chemically degraded under conditions similar to those expected in the near field and the leachate analysed. Separation of the products by HPLC gave direct identification of 2-C-(hydroxymethyl)-3-deoxy-D-erythro-pentonic (isosaccharinic) acid as one of the degradation products. More tentative assignments were made for glycolic, formic, lactic and acetic acids. A comparison was made with the degradation products suggested in the literature. The possible mechanisms and extent of cellulose degradation are discussed, as well as the factors affecting its degradation in the near field. The sorption of plutonium on to cement from a leachate produced under alkaline, anaerobic conditions is reported.

Alkaline Degradation of Cellulose: Estimation of the Concentration of Isosaccharinic Acid in Cement Porewater

1997 ◽  
Vol 506 ◽  
Author(s):  
L.R. Van Loon ◽  
M.A. Glaus ◽  
S. Stallone ◽  
A. Laube
Keyword(s):  
Radioactive Waste ◽  
Pore Water ◽  
Nuclear Power ◽  
Cellulose Degradation ◽  
Water Soluble ◽  
Complexing Agents ◽  
Substantial Part ◽  
Sorption Behaviour ◽  
Alkaline Conditions ◽  
Isosaccharinic Acid

ABSTRACTThe sorption of radionuclides on repository components (e.g. cement) is an important process since it controls the release of radionuclides from the repository [1]. A strong sorption of radionuclides is desirable since it will allow only a small release of radionuclides to the geo-and biosphere. The strong sorption behaviour of radionuclides, however, could possibly be decreased by several orders of magnitude by the presence of organic ligands. Ligands such as EDTA, NTA, citric acid etc. are inherent components of radioactive waste since these complexing agents are used in nuclear power stations for decontaminating purposes. Other ligands might be formed by degrading organic polymers present in low and intermediate level radioactive waste [2, 3]. Cellulose materials such as cotton, paper and wood form a substantial part (ca. 50 %) of the organic waste [1]. The use of large amounts of cement for constructing a repository causes alkaline environments in which the pH of the pore solution will remain above 12.5 for periods of the order of 105 years [4]. It is well known from the literature that cellulose is unstable under alkaline conditions and will degrade to water soluble, low molecular weight compounds by the peeling-off reaction [5]. The main degradation product of cellulose is isosaccharinic acid (ISA), which is stable under alkaline conditions [5-10]. ISA enhances the solubility of Pu(IV) [7, 8] and has an adverse effect on the sorption of Eu(III), Th(IV) and Ni(II) [6]. For instance, in a solution of 10-3 M ISA, the solubility of Pu(IV) at pH 12 increases by a factor of 20000 [11]. The sorption of Pu(IV) [8], Eu(III), Th(IV) and Ni(II) [6], however, was affected to only a minor extent. The observed effects were - by analogy with gluconic acid [12] - interpreted to be due to a strong complexation of these metals. The concentration of ISA in the pore water is the key parameter for evaluating its effect on radionuclide sorption [13].A full assessment of the effect of cellulose degradation on the sorption requires a detailed understanding of the mechanisms involved. The present study gives an overview of the different processes involved and describes how to quantify the concentration of isosaccharinic acid in the pore water of a repository.

The Effects of the Degradation of Organic Materials in the Near Field of a Radioactive Waste Repository

1991 ◽  
Vol 257 ◽  
Author(s):  
B.F. Greenfield ◽  
A.D. Moreton ◽  
M.W. Spindler ◽  
S.J. Williams ◽  
D.R. Woodwark
Keyword(s):  
Organic Materials ◽  
Degradation Products ◽  
Near Field ◽  
Water Soluble ◽  
Hydroxyl Groups ◽  
Modelling Studies ◽  
Deep Underground ◽  
Exchange Resins ◽  
The Uk ◽  
Isosaccharinic Acid

ABSTRACTUK Nirex Ltd are seeking to develop a deep underground repository for the disposal of solid ILW and LLW in the UK. The formation of water-soluble complexants from the degradation of the solid organic polymers and cellulosic materials present in such wastes may influence the solubility and sorption properties of a number of radioelements. A number of materials have been chemically degraded under alkaline, anaerobic conditions representative of the near field of the repository. Measurements of plutonium solubility in the leachates obtained show that the degradation of cellulose is of particular concern; the effects on the solubility can be several orders of magnitude greater than those of other organic materials. Products formed from the degradation of ion-exchange resins were found to have little effect. Solubilities of a number of other radioelements in aerobically degraded cellulose leachates are also given. The effect of reducing the ratio of celluloseto cement in the degradation experiments results in a decrease in plutonium solubility in the corresponding leachate. Several of the likely degradation products of cellulose have been individually synthesised including isosaccharinic acid, a key degradation product of cellulose. Enhanced plutonium solubilities have been measured in 10-3M solutions of these compounds. Sorption of plutonium onto cement from leachates obtained by the degradation of 10% cellulose in cement is reduced by about two orders of magnitude. Interaction with cement removes significant concentrations of complexants from solution. Thermodynamic modelling studies show that hydroxyl groups present in the compounds which result from the alkaline degradation of cellulose can strongly complex with plutonium.

The effect of cellulose degradation products on thorium sorption onto hematite: studies of a model ternary system

2012 ◽  
Vol 76 (8) ◽  
pp. 3381-3390 ◽  
Author(s):  
G. M. N. Baston ◽  
M. M. Cowper ◽  
T. G. Heath ◽  
T. A. Marshall ◽  
S. W. Swanton
Keyword(s):  
Degradation Products ◽  
Cellulose Degradation ◽  
Near Field ◽  
Principal Component ◽  
High Concentration ◽  
Sorption System ◽  
Model Predictions ◽  
The Impact ◽  
Isosaccharinic Acid ◽  
Good Agreement

AbstractCellulose degradation products (CDPs) can complex with radioelements causing solubility enhancement and sorption reduction, effects which are detrimental to the containment of radionuclides in the near field of a geological disposal facility and surrounding geosphere. Isosaccharinic acid (ISA) is the principal component of CDPs formed under the alkaline anaerobic conditions of a cement-based near field and appears to be largely responsible for the impact of CDPs on radionuclide solubility and sorption under near-field conditions. However, the situation appears to be more complicated under near-neutral pH geosphere conditions.A combined experimental and modelling study was undertaken to compare the impact of a CDP leachate to ISA in a simple model ternary sorption system consisting of hematite as a single mineral substrate, thorium as the radioelement and ISA or a CDP leachate as the complexant. Thorium sorbs strongly to hematite. A triple layer model for thorium sorption to hematite was refined to fit to the experimental data in the absence of ISA or CDP leachate; the effect of ISA on thorium sorption was then predicted.In the presence of CDP leachate, a significant reduction in thorium sorption was observed from pH 6 to 12 in good agreement with model predictions based on a high concentration of ISA. However, only a limited impact of ISA on thorium sorption was observed at pH 6 to 12, in contrast to predictions. The effects of ISA could be accounted for by assuming the formation of a ternary thorium–ISA–surface complex. The model has yet to be extended to the more complex CDP systems. Differences in the thorium speciation in solution due to the formation of a ternary calcium–thorium–ISA complex in the CDP leachate, which is absent from solutions with ISA only, provides the most likely explanation for the differences observed experimentally.

Sorption of radionuclides to a cementitious backfill material under near-field conditions

2012 ◽  
Vol 76 (8) ◽  
pp. 3401-3410 ◽  
Author(s):  
M. Felipe-Sotelo ◽  
J. Hinchliff ◽  
N. Evans ◽  
P. Warwick ◽  
D. Read
Keyword(s):  
Organic Compounds ◽  
Degradation Products ◽  
Cellulose Degradation ◽  
Near Field ◽  
Organic Ligand ◽  
Sorption Isotherms ◽  
Field Conditions ◽  
Sorption Behaviour ◽  
Backfill Material ◽  
Order Of Magnitude

AbstractThe sorption behaviour of I−, Cs+, Ni2+, Eu3+, Th4+ and UO2+2on NRVB (Nirex reference vault backfill) a possible vault backfill, at pH 12.8 was studied. Sorption isotherms generated were compared to results obtained in the presence of cellulose degradation products (CDP). Whereas Cs was not affected by the presence of the organic compounds, a notable reduction in the sorption of Th and Eu to cement was observed. The results also indicated limited removal of Ni from solution (with or without an organic ligand) by sorption, the concentration in solution seemingly being determined solely by solubility processes. In the case of uranium, the presence of CDP increased the sorption to cement by almost one order of magnitude. Further studies into the uptake of CDP by cement are being undertaken to identify the mechanism(s) responsible.

Validation of Analytical Methods for Tacrolimus Determination in Poly(ε-caprolactone) Nanocapsules and Identification of Drug Degradation Products

2021 ◽  
Vol 21 (12) ◽  
pp. 5920-5928
Author(s):  
Guilherme A. Camargo ◽  
Amanda M. Lyra ◽  
Fernanda M. Barboza ◽  
Barbara C. Fiorin ◽  
Flávio L. Beltrame ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Degradation Products ◽  
Multiple Reaction Monitoring ◽  
Forced Degradation ◽  
Alkaline Stress ◽  
Drug Degradation ◽  
Relative Standard ◽  
Polymeric Nanocapsules ◽  
Alkaline Conditions

The aim of this paper was to use chromatographic tools for validating an analytical method for the tacrolimus (TAC) determination in polymeric nanocapsules and for identifying the drug degradation products after alkaline stress. A rapid Ultra-High-Performance Liquid Chromatography coupled with photo-diode array (UHPLC-PDA) method was successfully performed using the following chromatographic conditions: the Shimadzu Shim-pack XR-ODS III C18 column (100 mm×2.00 mm, 2.2 μm), the mobile phase consisting of methanol and acidified ultrapure water (89:11 v/v), the flow rate of 0.55 mL·min−1, and the ultraviolet (UV) detection at 235 nm. This method was validated as per International Council for Harmonisation (ICH) guidelines. In addition, a TAC forced degradation assay was carried out after alkaline stress and its degradation products were investigated using Liquid Chromatography coupled tandem mass spectroscopy (LC-MS/MS). The calibration curve was linear in the range of 100.0–300.0 μg·mL−1 (r >0.9999). Accuracy was confirmed by the TAC recovery of 96.55 to 98.19%. Precision (intraday and interday) were demonstrated by relative standard deviation lower than 0.89% and 3.25%, respectively. Selectivity and robustness were also proved. The method developed it was successfully applied to quantify TAC from polymeric nanocapsules, showing a high loading efficiency rate (>96.47%). The main drug degradation product observed in a multiple reaction monitoring (MRM) experiment was m/z 844, confirming the susceptibility of TAC under alkaline conditions; this finding was first time described.

High Performance Liquid Chromatographic Analysis of Degradation Products of Tinidazole Pills

2013 ◽  
Vol 377 ◽  
pp. 261-264 ◽  
Author(s):  
Ting Xia ◽  
Jian Kang Wang ◽  
Tao Jiang ◽  
Jing Li
Keyword(s):  
High Performance ◽  
Ph Value ◽  
Degradation Products ◽  
High Performance Liquid Chromatographic ◽  
Melting Time ◽  
Alkaline Conditions ◽  
Direct Preparation ◽  
Liquid Chromatographic Analysis ◽  
Acidic Conditions ◽  
Liquid Chromatographic

To study the effect of different pH on degradation products of tinidazole pills and direct preparation of tinidazole pills, Tinidazole pills were prepared and the solution of different pH was compounded. The tinidazole content of pills and degradation products were determined by being heated at 80°C via high performance liqud chromatographic (HPLC). The number and concentration of tinidazole pills were increased with the increase of temperature and pH. Tinidazole pills in acidic conditions with the pH value within 4~5 were more stable than in neutral and alkaline conditions. It was shown that shortening the melting time and keeping pH value within 4~5 were in favor of preparation and assurance of pills quality.

Interaction of Eu(III) and Th(IV) With Sulfate-Resisting Portland Cement

1997 ◽  
Vol 506 ◽  
Author(s):  
E. Wieland ◽  
J. Tits ◽  
P. Spieler ◽  
J.P. Dobler
Keyword(s):  
Portland Cement ◽  
Pore Water ◽  
Degradation Products ◽  
Cellulose Degradation ◽  
Experimental Methodology ◽  
Batch Type ◽  
Kinetics Of ◽  
Isosaccharinic Acid

ABSTRACTThe uptake of Eu(III) and Th(IV) by a sulphate-resisting Portland cement has been investigated in batch type sorption experiments using 152 Eu and 234Th as tracers. Prior to performing sorption studies, the experimental methodology was assessed. The kinetics of Eu(III) and Th(IV) interactions with cement were measured for times up to about 130 days. The effect of isosaccharinic acid added to artificial cement pore water on Eu(III) and Th(IV) uptake was examined to elucidate the effect of cellulose degradation products.

Impact of iron(II) and oxygen on degradation of oak – modeling of the Vasa wood

Holzforschung ◽  
2014 ◽  
Vol 68 (6) ◽  
pp. 649-655 ◽  
Author(s):  
Shahin Norbakhsh ◽  
Ingela Bjurhager ◽  
Gunnar Almkvist
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
Oxalic Acid ◽  
Degradation Products ◽  
Cellulose Degradation ◽  
Chemical Degradation ◽  
Low Molecular Weight ◽  
Wood Degradation ◽  
Model Studies ◽  
Order Of Magnitude

Abstract In the wood of the Swedish 17th century warship Vasa, iron (Fe)-catalyzed chemical degradation has taken place after the salvation in 1961, which is manifested in increased acidity accompanied by cellulose degradation and reduced strength in the oak hull. Model studies on fresh oak impregnated with Fe(II) also led to tensile strength (TS) reduction in the same order of magnitude as observed in the wood of the Vasa. In the present study, further experiments have been performed concerning the Fe-catalyzed wood degradation. Namely, the degree of wood degradation was monitored quantitatively by measurement of the O2 consumption of Fe(II)-impregnated oak, kept in closed vials with different relative humidities (RH), as a function of time. The initial O2 consumption was high and declined with time. After 200 days, the accumulated O2 consumption was 0.3–0.4 mmol g-1 wood. Degradation products with low molecular weight were analyzed. The release of CO2 and oxalic acid (OA) was positively correlated with RH (0.235 and 0.044 mmol g-1, respectively, at RH98% after 200 days). Samples kept for 1500 days at RH54% had accumulated 0.044 mmol OA g-1 wood, which is equal to the average OA content in the interior of Vasa oak (corresponding to 4 mg g-1). Oak samples, from which extractives had been removed prior to Fe(II) impregnation, did not change their O2 consumption or TS reduction compared to the nonextracted samples, indicating that extractives are not essential for cellulose degradation in this context.

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