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Provide thermogravimetric analysis data to performance assessment

Description: Recent experimental testing has investigated the effect of a deposited mixed salt on the corrosion of carbon steel in high relative humidity air. This result is compared with previous studies where pure sodium chloride was deposited. There are aspects of the degradation process which are significantly different when the different salts are deposited. With deposited sodium chloride, corrosion occurs almost immediately after introduction of 80% RH air. With deposited mixed salts, there is an initial inhibition of corrosion in 80% RH air. After the initial inhibition period, corrosion occurs at localized regions of the specimen. At longer times, the specimen suffers extensive corrosion. A very porous and non-adherent corrosion product forms and readily spalls. The initial inhibition of the corrosion with the deposited mixed salt is most likely due to the bicarbonate component. Bicarbonate is a known inhibitor of general corrosion of carbon steel [Thomas, 1994] and a promoter of localized corrosion at moderate alkalinity when chloride ions are present [Marsh, 1985]. The results of this testing indicate that the bicarbonate component of thin water layers can initially inhibit corrosion of the carbon steel. With time, however, inhibition is lost. A mechanism for this loss of inhibition is suggested. It is plausible that moderately alkaline bicarbonate aqueous solutions could develop on the surface of a waste package due to Yucca Mountain water contacting the waste packages. Aqueous conditions might develop where carbon steel is susceptible to localized corrosion [Dunn, 1998]. The initial test results presented here suggest that the inhibition of general corrosion, and hence, the promotion of localized corrosion of carbon steel by thin aqueous bicarbonate-chloride layers may not be sustainable. Additional testing is underway to further understand the effects of thin aqueous solution chemistry on carbon steel corrosion.
Date: January 1, 1998
Creator: Gdowski, G.
Partner: UNT Libraries Government Documents Department

First increment of second specimen results to performance assessment-long term corrosion

Description: In this correspondence, we report the 6 month corrosion data of corrosion resistant alloys (alloys 825, C22 & C4, and Ti Gr 12 & Ti Gr 16, and Inconel 625) and one year data of corrosion-allowance materials (A387 Gr22, A516 Gr55 and A27 Gr70-40), intermediate resistance alloys (Monel 400 and CDA 715) and corrosion resistant materials (alloys C22 and 625 only).
Date: January 1, 1998
Creator: Wang, F.
Partner: UNT Libraries Government Documents Department

SYNCHROTRON X - RAY OBSERVATIONS OF A MONOLAYER TEMPLATE FOR MINERALIZATION.

Description: Mineral nucleation at a Langmuir film interface has been studied by synchrotron x-ray scattering. Diluted calcium bicarbonate solutions were used as subphases for arachidic and stearic acid monolayers, compressed in a Langmuir trough. Self-assembly of the monolayer template is observed directly, and subsequent crystal growth monitored in-situ.
Date: November 27, 2000
Creator: DIMASI,E. & GOWER,L.B.
Partner: UNT Libraries Government Documents Department

Chemical Fixation of CO2 in Coal Combustion Products and Recycling through Biosystems

Description: This Annual Technical Progress Report presents the principal results in enhanced growth of algae using coal combustion products as a catalyst to increase bicarbonate levels in solution. Optimal production of biomass depends on a number of factors. These factors include pH management, harvesting, and impact of auxiliary operations on the algae population. A number of experiments are presented which attempt to identify and characterize the impact of these factors.
Date: September 30, 2002
Creator: Copeland, C. Henry; Pier, Paul; Whitehead, Samantha & Behel, David
Partner: UNT Libraries Government Documents Department

Chemical Fixation of CO2 in Coal Combustion Products and Recycling through Biosystems

Description: This Annual Technical Progress Report presents the principle results in enhanced growth of algae using coal combustion products as a catalyst to increase bicarbonate levels in solution. A co-current reactor is present that increases the gas phase to bicarbonate transfer rate by a factor of five to nine. The bicarbonate concentration at a given pH is approximately double that obtained using a control column of similar construction. Algae growth experiments were performed under laboratory conditions to obtain baseline production rates and to perfect experimental methods. The final product of this initial phase in algae production is presented.
Date: September 30, 2001
Creator: Copeland, C. Henry; Pier, Paul; Whitehead, Samantha & Behel, David
Partner: UNT Libraries Government Documents Department

Inverse hydrochemical models of aqueous extracts tests

Description: Aqueous extract test is a laboratory technique commonly used to measure the amount of soluble salts of a soil sample after adding a known mass of distilled water. Measured aqueous extract data have to be re-interpreted in order to infer porewater chemical composition of the sample because porewater chemistry changes significantly due to dilution and chemical reactions which take place during extraction. Here we present an inverse hydrochemical model to estimate porewater chemical composition from measured water content, aqueous extract, and mineralogical data. The model accounts for acid-base, redox, aqueous complexation, mineral dissolution/precipitation, gas dissolution/ex-solution, cation exchange and surface complexation reactions, of which are assumed to take place at local equilibrium. It has been solved with INVERSE-CORE{sup 2D} and been tested with bentonite samples taken from FEBEX (Full-scale Engineered Barrier EXperiment) in situ test. The inverse model reproduces most of the measured aqueous data except bicarbonate and provides an effective, flexible and comprehensive method to estimate porewater chemical composition of clays. Main uncertainties are related to kinetic calcite dissolution and variations in CO2(g) pressure.
Date: October 10, 2008
Creator: Zheng, L.; Samper, J. & Montenegro, L.
Partner: UNT Libraries Government Documents Department

Near-infrared spectroscopy of lysed blood: pH effects

Description: Recent investigations by our group have demonstrated that near-infrared spectra collected from lysed blood solutions can be used to create clinically useful partial least squares (PSL) models for pH with standard errors of prediction below 0.05 pH units for pH range of 1 (6.8 to 7.8). Further work was performed in order to discern the primary source of pH information in the spectra. Results from these experiments are presented using spectral data acquired over the spectral range of 1300 nm to 2500 nm from plasma, lysed blood and amino acids solutions. Data were analyzed by principal component analysis (PCA) and loading vectors were compared. Experiments were designed to eliminate possible correlation between pH and other components in the system in order to ensure variations in the spectral data were due to hydrogen ion changes only. Results indicate that variations in the spectral characteristics of histidine mimic those seen in lysed blood, but not those seen in plasma, suggesting that histidine residues from hemoglobin are providing the necessary variation for pH modeling in the lysed blood solutions.
Date: December 1995
Creator: Alam, M. K.; Franke, J. E.; Maynard, J. D.; Robinson, M. R.; Niemczyk, T. M.; Rohrschieb, M. et al.
Partner: UNT Libraries Government Documents Department

Chemical Characteristics of Two Forested Ultisols and Two Forested Inceptisols Relevant to Anion Production and Mobility

Description: As a prelude to a basic program on soil leaching, some chemical characteristics of two forested Ultisols in eastern Tennessee and two forested Inceptisols in western Washington are discussed in relation to the production and mobility of anions. These soils were chosen in an attempt to provide a range of free iron (Fe) and aluminum (Al) contents (which are hypothesized to be related to anion adsorption) and carbon:nitrogen (C:N) ratios (which are hypothesized to be related to nitrate and bicarbonate production) for field experiments involving C, N, and anion salt additions. The Washington Inceptisols had high free Fe and Al in surface horizons and decreasing free Fe and Al levels with depth, whereas the reverse was true of the Tennessee Ultisols. The alderwood-red alder and Tarklin (sinkhole) soils had higher N concentrations and lower C:N ratios in their surface horizons than the Alderwood-Douglas-fir and Fullerton soils, respectively, but the reverse was true of subsurface horizons. Patterns of and relationships among the above properties and pH, Bray phosphorus (No. 2); adsorbed and soluble SO{sub 4}{sup 2-}, Cl{sup -}, and NO{sub 3}{sup -}; cation exchange capacity; and exchangeable cations are discussed.
Date: January 17, 2001
Creator: Johnson, D.W.
Partner: UNT Libraries Government Documents Department

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

Description: This report describes research conducted between April 1, 2004 and June 30, 2004 on the preparation and use of dry regenerable sorbents for removal of carbon dioxide from flue gas. Support materials and supported sorbents were prepared by spray drying. Sorbents consisting of 20 to 50% sodium carbonate on a ceramic support were prepared by spray drying in batches of approximately 300 grams. The supported sorbents exhibited greater carbon dioxide capture rates than unsupported calcined sodium bicarbonate in laboratory tests. Preliminary process design and cost estimation for a retrofit application suggested that costs of a dry regenerable sodium carbonate-based process could be lower than those of a monoethanolamine absorption system. In both cases, the greatest part of the process costs come from power plant output reductions due to parasitic consumption of steam for recovery of carbon dioxide from the capture medium.
Date: July 1, 2004
Creator: Green, David A.; Turk, Brian S.; Portzer, Jeffrey W.; Gupta, Raghubir P.; McMichael, William J. & Nelson, Thomas
Partner: UNT Libraries Government Documents Department

Annual Groundwater Detection Monitoring Report for the Idaho CERCLA Disposal Facility (2008)

Description: This report presents the data collected for groundwater detection monitoring at the Idaho Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Disposal Facility (ICDF) during calendar year 2008. The detection-monitoring program developed for the ICDF groundwater-monitoring wells is applicable to six wells completed in the uppermost portion of the Snake River Plain Aquifer − five wells downgradient of the ICDF and one well upgradient. The ICDF detection-monitoring program was established to meet the substantive requirements of Title 40 Code of Federal Regulations (CFR) Parts 264.97 and 264.98, which are applicable or relevant and appropriate requirements under CERCLA. Semiannual groundwater samples were collected and analyzed for indicator parameters in March and September. The indicator parameters focus on constituents that are found in higher concentrations in ICDF leachate than in groundwater (bicarbonate alkalinity, sulfate, U-233, U-234, and U-238). The only detection monitoring limits that were exceeded were for bicarbonate alkalinity. Bicarbonate alkalinity is naturally occurring in groundwater. Bicarbonate alkalinity found in ICDF detection monitoring wells is not a result of waste migration from the ICDF landfill or the evaporation pond. The U.S. Department of Energy will continue with detection monitoring for the ICDF, which is semiannual sampling for indicator parameters.
Date: July 31, 2009
Creator: Cahn, Lorie
Partner: UNT Libraries Government Documents Department

RAPID CASING CORROSION IN HIGH TEMPERATURE LIQUID DOMINATED GEOTHERMAL FIELDS

Description: Downhole logging and workover operations on 12-20 year old wells in several high temperature, liquid-dominated geothermal fields in New Zealand has shown that severe corrosion has commonly occurred in the production casing string where this is unprotected by larger diameter casings. To date corrosion products from only one well have been examined in detail. These indicate that corrosion attack commences at the outer casing wall and continues at a rate as great as 0.8mm/year. Rapid corrosion has been attributed to neutral or slightly acid high bicarbonate waters formed by the absorption of steam and gas into shallow aquifers not directly connected to the deeper, high chloride reservoir.
Date: January 22, 1985
Creator: Bixley, P.F. & Wilson, D.M.
Partner: UNT Libraries Government Documents Department

Initiating the D&D Project for the EBR-II

Description: A novel decommissioning project is underway to close the Experimental Breeder Reactor-II (EBR-II) “fast” reactor at the Idaho National Laboratory (INL), Materials and Fuels Complex (MFC) facility near Idaho Falls, ID. The facility was placed in cold shutdown in 1994 and work began on the removal of the metallic sodium coolant. The bulk of the sodium was drained and treated beginning in 2001. The residual sodium heel was chemically passivated to render it less reactive in 2005 using a novel carbon dioxide treatment. Approximately 700 kg of metallic sodium and 3500 kg of sodium bicarbonate remain in the facility. A RCRA Waste Treatment Permit, issued in 2002 by the State of Idaho Department of Environmental Quality, requires annual progress toward closure of the facility, and that all regulated materials be removed or deactivated, and the waste products removed by 2022. The baseline sodium removal technology would result in about 100,000 gallons of low-level waste solution requiring treatment along with separate handling of the large components (intermediate heat exchanger, rotating plug, etc) outside of the primary tank.
Date: August 1, 2010
Creator: Demmer, Rick
Partner: UNT Libraries Government Documents Department

Final Report - Phase II - Biogeochemistry of Uranium Under Reducing and Re-oxidizing Conditions: An Integrated Laboratory and Field Study

Description: Our understanding of subsurface microbiology is hindered by the inaccessibility of this environment, particularly when the hydrogeologic medium is contaminated with toxic substances. Past research in our labs indicated that the composition of the growth medium (e.g., bicarbonate complexation of U(VI)) and the underlying mineral phase (e.g., hematite) significantly affects the rate and extent of U(VI) reduction and immobilization through a variety of effects. Our research was aimed at elucidating those effects to a much greater extent, while exploring the potential for U(IV) reoxidation and subsequent re-mobilization, which also appears to depend on the mineral phases present in the system. The project reported on here was an extension ($20,575) of the prior (much larger) project. This report is focused only on the work completed during the extension period. Further information on the larger impacts of our research, including 28 publications, can be found in the final report for the following projects: 1) Biogeochemistry of Uranium Under Reducing and Re-oxidizing Conditions: An Integrated Laboratory and Field Study Grant # DE-FG03-01ER63270, and 2) Acceptable Endpoints for Metals and Radionuclides: Quantifying the Stability of Uranium and Lead Immobilized Under Sulfate Reducing Conditions Grant # DE-FG03-98ER62630/A001 In this Phase II project, the toxic effects of uranium(VI) were studied using Desulfovibrio desulfuricans G20 in a medium containing bicarbonate or 1, 4-piperazinediethane sulfonic acid disodium salt monohydrate (PIPES) buffer (each at 30 mM, pH 7). The toxicity of uranium(VI) was dependent on the medium buffer and was observed in terms of longer lag times and in some cases, no measurable growth. The minimum inhibiting concentration (MIC) was 140 M U(VI) in PIPES buffered medium. This is 36 times lower than previously reported for D. desulfuricans. These results suggest that U(VI) toxicity and the detoxification mechanisms of G20 depend greatly on the chemical forms of U(VI) present ...
Date: September 28, 2006
Creator: Peyton, Brent & Sani, Rajesh
Partner: UNT Libraries Government Documents Department

Carbon Dioxide Capture from Flue Gas Using Dry, Regenerable Sorbents

Description: This report describes research conducted between October 1, 2005, and December 31, 2005, on the use of dry regenerable sorbents for removal of carbon dioxide (CO{sub 2}) from flue gas from coal combustion. A field test was conducted to examine the extent to which RTI's supported sorbent can be regenerated in a heated, hollow screw conveyor. This field test was conducted at the facilities of a screw conveyor manufacturer. The sorbent was essentially completely regenerated during this test, as confirmed by thermal desorption and mass spectroscopy analysis of the regenerated sorbent. Little or no sorbent attrition was observed during 24 passes through the heated screw conveyor system. Three downflow contactor absorption tests were conducted using calcined sodium bicarbonate as the absorbent. Maximum carbon dioxide removals of 57 and 91% from simulated flue gas were observed at near ambient temperatures with water-saturated gas. These tests demonstrated that calcined sodium carbonate is not as effective at removing CO{sub 2} as are supported sorbents containing 10 to 15% sodium carbonate. Delivery of the hollow screw conveyor for the laboratory-scale sorbent regeneration system was delayed; however, construction of other components of this system continued during the quarter.
Date: January 1, 2006
Creator: Green, David A.; Nelson, Thomas O.; Turk, Brian S.; Box, Paul D.; Weber, Andreas & Gupta, Raghubir P.
Partner: UNT Libraries Government Documents Department

POST-OPERATIONAL TREATMENT OF RESIDUAL NA COOLLANT IN EBR-2 USING CARBONATION

Description: At the end of 2002, the Experimental Breeder Reactor Two (EBR-II) facility became a U.S. Resource Conservation and Recovery Act (RCRA) permitted site, and the RCRA permit1 compelled further treatment of the residual sodium in order to convert it into a less reactive chemical form and remove the by-products from the facility, so that a state of RCRA 'closure' for the facility may be achieved (42 U.S.C. 6901-6992k, 2002). In response to this regulatory driver, and in recognition of project budgetary and safety constraints, it was decided to treat the residual sodium in the EBR-II primary and secondary sodium systems using a process known as 'carbonation.' In early EBR-II post-operation documentation, this process is also called 'passivation.' In the carbonation process (Sherman and Henslee, 2005), the system containing residual sodium is flushed with humidified carbon dioxide (CO{sub 2}). The water vapor in the flush gas reacts with residual sodium to form sodium hydroxide (NaOH), and the CO{sub 2} in the flush gas reacts with the newly formed NaOH to make sodium bicarbonate (NaHCO{sub 3}). Hydrogen gas (H{sub 2}) is produced as a by-product. The chemical reactions occur at the exposed surface of the residual sodium. The NaHCO{sub 3} layer that forms is porous, and humidified carbon dioxide can penetrate the NaHCO{sub 3} layer to continue reacting residual sodium underneath. The rate of reaction is controlled by the thickness of the NaHCO{sub 3} surface layer, the moisture input rate, and the residual sodium exposed surface area. At the end of carbonation, approximately 780 liters of residual sodium in the EBR-II primary tank ({approx}70% of original inventory), and just under 190 liters of residual sodium in the EBR-II secondary sodium system ({approx}50% of original inventory), were converted into NaHCO{sub 3}. No bare surfaces of residual sodium remained after treatment, and all remaining ...
Date: March 8, 2011
Creator: Sherman, S. & Knight, C.
Partner: UNT Libraries Government Documents Department

Long-Term Stewardship of Mixed Wastes: Passive Reactive Barriers for Simultaneous In Situ Remediation of Chlorinated Solvent, Heavy Metal, and Radionuclide Contaminants

Description: This project report summarizes the results of a 3-way collaboration between researchers at Montana State University’s (MSU’s) Center for Biofilm Engineering (CBE) (Drs. Robin Gerlach and Al Cunningham), the WSU/NSF IGERT Center for Multiphase Environmental Research (CMER) at Washington State University (WSU) (Dr. Brent Peyton who recently moved to MSU), and the Idaho National Laboratory (INL) (Drs. William Apel and Frank Roberto). At WSU, removal of uranium (U) from aqueous solution was studied using Cellulomonas sp. strain ES6, under anaerobic, non-growth conditions. The Cellulomonadaceae are environmentally relevant subsurface bacteria, and strain ES6 was isolated from the DOE Hanford subsurface. To better understand the role of the pH buffer in the U immobilization process, both bicarbonate and PIPES buffers were used. Our results show for the first time the strain ES6 has multiple U immobilization mechanisms within one organism. Citations to resulting publications are included in the report.
Date: December 4, 2007
Creator: Peyton, Brent, M.; Gerlach, Robin; Cunningham, Al, B.; Apel, William, A. & Roberto, Francisco
Partner: UNT Libraries Government Documents Department

Bicarbonate leaching of uranium

Description: The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented.
Date: July 1998
Creator: Mason, C.
Partner: UNT Libraries Government Documents Department

A complete remediation process for a uranium-contaminated site and application to other sites

Description: During the summer of 1996 the authors were able to test, at the pilot scale, the concept of leaching uranium (U) from contaminated soils. The results of this pilot scale operation showed that the system they previously had developed at the laboratory scale is applicable at the pilot scale. The paper discusses these results, together with laboratory scale results using soil from the Fernald Environmental Management Project (FEMP), Ohio. These FEMP results show how, with suitable adaptations, the process is widely applicable to other sites. The purpose of this paper is to describe results that demonstrate remediation of uranium-contaminated soils may be accomplished through a leach scheme using sodium bicarbonate.
Date: December 31, 1998
Creator: Mason, C.F.V.; Lu, N.; Kitten, H.D.; Williams, M. & Turney, W.R.J.R.
Partner: UNT Libraries Government Documents Department

The use of carbonate lixiviants to remove uranium from uranium-contaminated soils

Description: The objective of this research was to design an extraction media and procedure that would selectively remove uranium without adversely affecting the soils` physicochemical characteristics or generating secondary waste forms difficult to manage or dispose of. Investigations centered around determining the best lixivant and how the various factors such as pH, time, and temperature influenced extraction efficiency. Other factors investigated included the influence of attrition scrubbing, the effect of oxidants and reductants and the recycling of lixiviants. Experimental data obtained at the bench- and pilot-scale levels indicated 80 to 95% of the uranium could be removed from the uranium-contaminated soils by using a carbonate lixiviant. The best treatment was three successive extractions with 0.25 M carbonate-bicarbonate (in presence of KMnO{sub 4} as an oxidant) at 40 C followed with two water rinses.
Date: August 1, 1997
Creator: Francis, C.W.; Lee, S.Y.; Wilson, J.H.; Timpson, M.E. & Elless, M.P.
Partner: UNT Libraries Government Documents Department

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

Description: Electrobalance studies of calcination and carbonation of sodium bicarbonate materials were conducted at Louisiana State University. Calcination in an inert atmosphere was rapid and complete at 120 C. Carbonation was temperature dependent, and both the initial rate and the extent of reaction were found to decrease as temperature was increased between 60 and 80 C. A fluidization test apparatus was constructed at RTI and two sodium bicarbonate materials were fluidized in dry nitrogen at 22 C. The bed was completely fluidized at between 9 and 11 in. of water pressure drop. Kinetic rate expression derivations and thermodynamic calculations were conducted at RTI. Based on literature data, a simple reaction rate expression, which is zero order in carbon dioxide and water, was found to provide the best fit against reciprocal temperature. Simulations based on process thermodynamics suggested that approximately 26 percent of the carbon dioxide in flue gas could be recovered using waste heat available at 240 C.
Date: May 1, 2001
Creator: Green, David A.; Turk, Brian S.; Gupta, Raghubir P.; Lopez-Ortiz, Alejandro; Harrison, Douglas P. & Liang, Ya
Partner: UNT Libraries Government Documents Department

Pilot-scale treatability testing -- Recycle, reuse, and disposal of materials from decontamination and decommissioning activities: Soda blasting demonstration

Description: The US Department of Energy (DOE) is in the process of defining the nature and magnitude of decontamination and decommissioning (D and D) obligations at its sites. With disposal costs rising and available storage facilities decreasing, DOE is exploring and implementing new waste minimizing D and D techniques. Technology demonstrations are being conducted by LMES at a DOE gaseous diffusion processing plant, the K-25 Site, in Oak Ridge, Tennessee. The gaseous diffusion process employed at Oak Ridge separated uranium-235 from uranium ore for use in atomic weapons and commercial reactors. These activities contaminated concrete and other surfaces within the plant with uranium, technetium, and other constituents. The objective of current K-25 D and D research is to make available cost-effective and energy-efficient techniques to advance remediation and waste management methods at the K-25 Site and other DOE sites. To support this objective, O`Brien and Gere tested a decontamination system on K-25 Site concrete and steel surfaces contaminated with radioactive and hazardous waste. A scouring system has been developed that removes fixed hazardous and radioactive surface contamination and minimizes residual waste. This system utilizes an abrasive sodium bicarbonate medium that is projected at contaminated surfaces. It mechanically removes surface contamination while leaving the surface intact. Blasting residuals are captured and dissolved in water and treated using physical/chemical processes. Pilot-scale testing of this soda blasting system and bench and pilot-scale treatment of the generated residuals were conducted from December 1993 to September 1994.
Date: August 1, 1995
Partner: UNT Libraries Government Documents Department

Comparison of neptunium sorption results using batch and column techniques

Description: We used crushed-rock columns to study the sorption retardation of neptunium by zeolitic, devitrified, and vitric tuffs typical of those at the site of the potential high-level nuclear waste repository at Yucca Mountain, Nevada. We used two sodium bicarbonate waters (groundwater from Well J-13 at the site and water prepared to simulate groundwater from Well UE-25p No. 1) under oxidizing conditions. It was found that values of the sorption distribution coefficient, Kd, obtained from these column experiments under flowing conditions, regardless of the water or the water velocity used, agreed well with those obtained earlier from batch sorption experiments under static conditions. The batch sorption distribution coefficient can be used to predict the arrival time for neptunium eluted through the columns. On the other hand, the elution curves showed dispersivity, which implies that neptunium sorption in these tuffs may be nonlinear, irreversible, or noninstantaneous. As a result, use of a batch sorption distribution coefficient to calculate neptunium transport through Yucca Mountain tuffs would yield conservative values for neptunium release from the site. We also noted that neptunium (present as the anionic neptunyl carbonate complex) never eluted prior to tritiated water, which implies that charge exclusion does not appear to exclude neptunium from the tuff pores. The column experiments corroborated the trends observed in batch sorption experiments: neptunium sorption onto devitrified and vitric tuffs is minimal and sorption onto zeolitic tuffs decreases as the amount of sodium and bicarbonate/carbonate in the water increases.
Date: August 1, 1996
Creator: Triay, I.R.; Furlano, A.C.; Weaver, S.C.; Chipera, S.J. & Bish, D.L.
Partner: UNT Libraries Government Documents Department

CHEMICAL FIXATION OF CO2 IN COAL COMBUSTION PRODUCTS AND RECYCLING THROUGH BIOSYSTEMS

Description: This Annual Technical Progress Report presents the principle results in enhanced growth of algae using coal combustion products as a catalyst to increase bicarbonate levels in solution. A co-current reactor is present that increases the gas phase to bicarbonate transfer rate by a factor of five to nine. The bicarbonate concentration at a given pH is approximately double that obtained using a control column of similar construction. Algae growth experiments were performed under laboratory conditions to obtain baseline production rates and to perfect experimental methods. The final product of this initial phase in algae production is presented. Algal growth can be limited by several factors, including the level of bicarbonate available for photosynthesis, the pH of the growth solution, nutrient levels, and the size of the cell population, which determines the available space for additional growth. In order to supply additional CO2 to increase photosynthesis and algal biomass production, fly ash reactor has been demonstrated to increase the available CO2 in solution above the limits that are achievable with dissolved gas alone. The amount of dissolved CO2 can be used to control pH for optimum growth. Periodic harvesting of algae can be used to maintain algae in the exponential, rapid growth phase. An 800 liter scale up demonstrated that larger scale production is possible. The larger experiment demonstrated that indirect addition of CO2 is feasible and produces significantly less stress on the algal system. With better harvesting methods, nutrient management, and carbon dioxide management, an annual biomass harvest of about 9,000 metric tons per square kilometer (36 MT per acre) appears to be feasible. To sequester carbon, the algal biomass needs to be placed in a permanent location. If drying is undesirable, the biomass will eventually begin to aerobically decompose. It was demonstrated that algal biomass is a suitable feed ...
Date: December 15, 2003
Creator: Copeland, C. Henry; Pier, Paul; Whitehead, Samantha; Enlow, Paul; Strickland, Richard & Behel, David
Partner: UNT Libraries Government Documents Department