2 edition of effects of cellulose degradation on waste plutonium solubility found in the catalog.
effects of cellulose degradation on waste plutonium solubility
Wayne Nicholas Harrison
Thesis (Ph.D) - University of Birmingham, School of Chemistry, 1992.
|Statement||by Wayne Nicholas Harrison.|
Degradation problems associated with later our utilization of waste cellulose and developing products based on waste cellulose as (HPC) is a derivative of cellulose with both water solubility and organic solubility. It is used as an excipient, and topical ophthalmic protectant and d, Nippon Soda, Shin-Etsu, Huzhou. Lignin is a class of complex organic polymers that form key structural materials in the support tissues of vascular plants and some algae. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot ally, lignins are cross-linked phenolic polymers.
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Download Citation | The Degradation of Cellulose in the Near Field of a Radioactive Waste Repository | UK Nirex Ltd is seeking to develop a deep underground repository of the disposal of solid low.
Degradation of cellulose. Degradation was initiated by dissolving 25 g of cellulose (microcrystalline powder, Alfa Aesar) in 1 l of artificial cement pore water (pH ) and in water respectively. The artificial cement water was prepared by dissolving 5 g of Ca(OH) 2 (Alfa Aesar, 95%) in 1 l of Millipore water under stirring for 1 h.
The Cited by: 2. Cellulose degradation under alkaline conditions is of relevance to the mobility of many cations of the transition metal, lanthanide, and actinide series in the geosphere because strong complexants such as isosaccharinic acids, 3-deoxyC-hydroxymethyl-D-erythro-pentonic acid (α-ISA) and 3-deoxyC-hydroxymethyl-D-threo-pentonic acid (β-ISA) may be formed.
In the context of the Cited by: The degradation of cellulose (a substantial component of low- and intermediate-level radioactive waste) under alkaline conditions occurs via two main processes: a peeling-off reaction and a.
Cellulose is a linear condensation polymer consisting of d-anhydroglucopyranose units (often loosely called glucose units) linked by β-1,4-glycosidic bonds ().Under alkaline, anaerobic conditions at temperatures below about °C the predominant mechanism of cellulose degradation, is by a reaction that takes place at the reducing end group of the chain and ruptures the 1,4-glycosidic Cited by: The Microbiology of Nuclear Waste Disposal is a state-of-the-art reference featuring contributions focusing on the impact of microbes on the safe long-term disposal of nuclear waste.
This book is the first to cover this important emerging topic, and is written for a wide audience encompassing regulators, implementers, academics, and other. 3) Determining the effect these degradation products have on the behaviour of radionuclides in the near-field and geosphere.
This report presents the findings of this programme of work and describes the methods employed to simulate the conditions within a GDF that could result in the degradation of cellulose. The report also describes solubility and sorption studies undertaken on europium and thorium, as surrogates for trivalent and quadravalent cationic radionuclides, to investigate the impact cellulose degradation products have on radionuclide transport NNL(12) Part A.
DRINK model the first stage of cellulose degradation is the hydrolysis of cellulose described by a first order kinetic reaction with a pH dependent hydrolysis constant .
The profiles of cellulose concentration (Figure 2a) result from hydrolysis in the saturated zone, together with transfer of. Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process.
Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. 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 M 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. Cellulose acetate polymer is used to make a variety of consumer products including textiles, plastic films, and cigarette filters.
A review of degradation mechanisms, and the possible approaches to diminish the environmental persistence of these materials, will clarify the current and potential degradation rates of these products after disposal.
Various studies have been conducted on. In this research, enzymatic treatment as an environmental friendly process has been used for recycling process of old cellulosic wastes such as cotton, viscose, and lyocell. Cellulase hydrolyses cellulosic chains and shortens cellulosic fibers. This study investigates to detect the optimum enzyme concentration and time of treatments for suitable changes of length and weight loss.
The chemical and microbial degradation of cellulose in the near field of a repository for radioactive wastes. all the cellulose was assumed to be converted to complexants that could increase the solubility and decrease the sorption of radionuclides in the near field.
This contradiction in the approach of the groundwater and gas pathway. The impact of α-d-isosaccharinic acid (HISA), a degradation product of cellulose, on the solubility and redox behavior of hydrous Pu(IV) oxide was investigated from undersaturation conditions under Ar atmosphere in m NaCl–NaOH–NaISA conditions were buffered with hydroquinone (HQ) or Sn(II), resulting in (pe + pH m) ≈ andrespectively.
A number of the hydroxycarboxylic acids generated by the alkaline degradation of cellulosic wastes under reducing conditions in a cementitious repository can significantly increase the solubility of the actinides at high pH, especially plutonium.
The solubility of plutonium at pH 12, in the presence of a range of hydroxycarboxylic acids containing a number of hydroxyl groups and between one and three. Microbial degradation of isosaccharinic acid under conditions representative for the far field of radioactive waste disposal facilities.
Mineralogical Magazine79 (6), B. Greenfield's 6 research works with 83 citations and reads, including: The Degradation of Cellulose in the Near Field of a Radioactive Waste Repository. Abstract. The solubility of β–Ni(OH) 2 (cr) was investigated at T=(22±2)°C in the absence and presence of α-isosaccharinic acid (ISA), the main degradation product of cellulose under alkaline pH conditions.
Batch solubility experiments were performed from undersaturation conditions under. long-term isolation of radioactive waste from the accessible any effects that may inﬂuence the solubility and sorption of the magnitude of the effect of chemical degradation of cellulose.
Enzyme solutions produced for commercial purposes unrelated to waste management have the potential for reducing the volume of wastes in streams containing cellulose, lipid and protein materials. For example, the authors have shown that cellulases used in denim production and in detergent formulations are able to digest cellulose-containing sorbents and other cellulose-based wastes contaminated.
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. The book consists of 21 chapters by subject matter experts and is divided into four parts: Soil Microenvironment and Biotransformation Mechanisms; Synergistic effects between substrates and Microbes; Polyhydroxyalakanoates: Resources, Demands and Sustainability; and Cellulose based biomaterials: Benefits and challenges.
Radioactive Waste Management Directorate Building Curie Avenue Harwell Oxford Didcot causing solubility enhancement in the near field and a significant amount of work had been undertaken to study the effects of cellulose degradation products (CDPs) on the sorption of a number of radionuclides onto a range of rock types.
Isosaccharinic acid (ISA) has been identified as a major product of the alkaline anaerobic degradation of cellulose (Machell and Richards, ), and it appears to be largely responsible for the impact of cellulose degradation products (CDPs) on radionuclide solubility and sorption under cementitious near-field conditions (e.g.
Heath and Williams, ; Van Loon and Glaus, ). A Review of Cellulose Degradation and the Fate of Degradation Products Under Repository Conditions fields relevant to radioactive waste disposal sites is a clear area for further research.
An improved Radiolytic Degradation of CDPs 24 Solubility and Sorption of ISA and CDPs Cellulose-containing waste. Cellulose-containing waste, mainly paper filters that incorporate α-emitters (a.o. plutonium and americium) cannot be incinerated and is cemented for deep geological disposal.
After emplacement of the waste containers, the disposal galleries will. C ellulose is a polymer of –14, glucose units linked by β-1,4 glycosidic bonds and is the main component of plant cell walls. As such, it is one of the most abundant polymers on Earth (Beguin and Aubert, ).Cellulose polymers are oriented in parallel and form highly ordered, insoluble crystalline domains interspersed by more disordered amorphous regions.
Isogai investigated the solubility of cellulose from several sources but never succeeded in preparing cellulose solutions of higher concentrations than 5 %. A method for complete dissolution of cellulose in lye solutions was also patented in For cellulose to dissolve in alkaline aqueous media, it needs to be cooled well below room.
The cellulosic fraction of waste is the main determinant of cell growth. It appears to be the sugar acids arising from alkaline degradation of cellulose which cause enhanced plutonium solubility.
The potentially beneficial reduction of chemically derived polyhydroxy acids. "Microorganisms have been detected in TRU wastes, Pu-contaminated soils, low-level radioactive wastes, backfill materials, natural analog sites, and waste-repository sites slated for high-level wastes.
Seventy percent of the TRU waste consists of cellulose and other biodegradable organic compounds. Biodegradation of cellulose under the hypersaline conditions such as in the WIPP. INTRODUCTION. Disposal of radioactive waste in a geological disposal facility (GDF) is considered the safest long-term management solution for these materials (Department for Business, Energy and Industrial Strategy ).Different GDF concepts have been proposed, and are under development internationally, that address different geological settings, waste inventories and waste types.
The dissolution process of cellulose aerogels is an important part of their production. However, if the cellulose is severely degraded during the dissolution process, the quality may be low.
To evaluate the degradation of cellulose during the dissolution process using calcium thiocyanate, the hydrolysis and oxidation of cellulose were evaluated by the change in absolute molecular weight and by. Accidental releases, nuclear weapons testing, and inadequate practices of radioactive waste disposal are the principal human activities responsible for radioactive contamination as a new and global form of soil degradation.
Understanding the radionuclide distribution, mobility and bioavailability, as well as the changes caused by the variation of environmental conditions, is essential for soil.
B.F. Greenfield, M.H. Hurdus, M.W. Spindler, H.P. Thomason, The effects of the products from the anaerobic degradation of cellulose on the solubility and sorption of radioelements in the near field, NSS/R, Google Scholar. Reactor set-up and chemical analysis.
Two cellulose degradation product (CDP) soil reactors were prepared by the addition of the collected soil (5g) to mL bottles in duplicate, which was then diluted using 72mL of a previously described anaerobic mineral (pH ) media under a stream of nitrogen .To these reactors, a previously described CDP (8mL) leachate was added .
The proposed function of the barrier system is described in terms of waste dissolution, diffusion and sorption. The alkaline degradation of cellulose in the waste will produce the complexing agent gluco-isosaccharinic acid (ISA).
Experiments made to study the impact of ISA on radionuclide solubility and sorption in cementitious systems are. The chemical and microbial degradation of cellulose in the near field of a repository for radioactive wastes. Waste Manag.
; – Bailey MJ. Utilization of glucoisosaccharinic acid by a bacterial isolate unable to metabolize glucose.
Appl Microbiol Biotechnol. ; – Berner UR. Evolution of pore water chemistry during. Preparation and analysis of cellulose degradation products (CDP) CDP were prepared using the methods of Cowper et al  with standard laboratory paper tissue used as the cellulose source for (g) was added to L of N 2 flushed M NaOH and 10 gL-1 Ca(OH) 2 in a pressure vessel.
The headspace was flushed with N 2 for 30 min, before being sealed and placed in. Nickel in solution. In this study the fate of non-radioactive Ni was explored in ISA-degrading, Fe(III)-reducing microbial cultures. Prior to the study, abiotic factors in the system that could control the solubility of Ni were considered, e.g.
the presence of Fe(III)oxyhydroxide that exhibits high adsorptive capacities for metal ions The solubility of Ni (at mM Ni and 1 mM Ni) was. Case 3 has two parts. In Case 3A, cellulose degradation products are assumed to enhance the solubility of solubility limited phases and to decrease sorption; and, in Case 3B, cellulose degradation products are assumed not to have any effect on .Isosaccharinic acid (ISA) is a six-carbon sugar acid which is formed by the action of calcium hydroxide on lactose and other is of interest because it may form in intermediate-level nuclear waste stores when cellulose is degraded by the calcium hydroxide in cements such as Portland calcium salt of the alpha form of ISA is very crystalline and quite insoluble in cold.Banchorndhevakul S.
Effect of urea and urea-gamma treatments on cellulose degradation of Thai rice straw and corn stalk. Radiation Physics and Chemistry. ; 64 ()– doi: /sx(01)