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Sample records for activated carbon sorbents

  1. Modified Activated Carbon Perchlorate Sorbents

    DTIC Science & Technology

    2007-01-25

    nitrosodimethylamine precursors in municipal wastewater treatment plants. Environ. Sci. Technol., 2004. 38: p. 1445-1454. 15. Shmidt, V., K. Rybakov...Engineering and Management, 1994. 141: p. 12. 33. Walker, G. and L. Weatherley, Biological Activated Carbon Treatment of Industrial Wastewater in... Treatment with Ammonia (NAC), Urea-formaldehyde Resin (UAC), and Hydrogen (HAC). Data are Indicated by the Symbol and Least Squares Fit of the Langmuir

  2. Activated-Carbon Sorbent With Integral Heat-Transfer Device

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Yavrouian, Andre

    1996-01-01

    Prototype adsorption device used, for example, in adsorption heat pump, to store natural gas to power automobile, or to separate components of fluid mixtures. Device includes activated carbon held together by binder and molded into finned heat-transfer device providing rapid heating or cooling to enable rapid adsorption or desorption of fluids. Concepts of design and fabrication of device equally valid for such other highly thermally conductive devices as copper-finned tubes, and for such other high-surface-area sorbents as zeolites or silicates.

  3. Chemically and biologically modified activated carbon sorbents for the removal of lead ions from aqueous media.

    PubMed

    Mahmoud, Mohamed E; Abdel-Fattah, Tarek M; Osman, Maher M; Ahmed, Somia B

    2012-01-01

    A method is described for hybridization of the adsorption and biosorption characteristics of chemically treated commercial activated carbon and baker's yeast, respectively, for the formation of environmental friendly multifunctional sorbents. Activated carbon was loaded with baker's yeast after acid-base treatment. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) Spectroscopy were used to characterize these sorbents. Moreover, the sorption capabilities for lead (II) ions were evaluated. A value of 90 μmol g(-1) was identified as the maximum sorption capacity of activated carbon. Acid-base treatment of activated carbon was found to double the sorption capacity (140-180 μmol g(-1)). Immobilization of baker's yeast on the surface of activated carbon sorbents was found to further improve the sorption capacity efficiency of lead to 360, 510 and 560 μmol g(-1), respectively. Several important factors such as pH, contact time, sorbent dose, lead concentration and interfering ions were examined. Lead sorption process was studied and evaluated by several adsorption isotherms and found to follow the Langmuir and BET models. The potential applications of various chemically and biologically modified sorbents and biosorbents for removal of lead from real water matrices were also investigated via multistage micro-column technique and the results referred to excellent recovery values of lead (95.0-99.0 ± 3.0-5.0 %).

  4. Magnetite impregnation effects on the sorbent properties of activated carbons and biochars.

    PubMed

    Han, Zhantao; Sani, Badruddeen; Mrozik, Wojciech; Obst, Martin; Beckingham, Barbara; Karapanagioti, Hrissi K; Werner, David

    2015-03-01

    This paper discusses the sorbent properties of magnetic activated carbons and biochars produced by wet impregnation with iron oxides. The sorbents had magnetic susceptibilities consistent with theoretical predictions for carbon-magnetite composites. The high BET surface areas of the activated carbons were preserved in the synthesis, and enhanced for one low surface area biochar by dissolving carbonates. Magnetization decreased the point of zero charge. Organic compound sorption correlated strongly with BET surface areas for the pristine and magnetized materials, while metal cation sorption did not show such a correlation. Strong sorption of the hydrophobic organic contaminant phenanthrene to the activated carbon or biochar surfaces was maintained following magnetite impregnation, while phenol sorption was diminished, probably due to enhanced carbon oxidation. Copper, zinc and lead sorption to the activated carbons and biochars was unchanged or slightly enhanced by the magnetization, and iron oxides also contributed to the composite metal sorption capacity. While a magnetic biochar with 219 ± 3.7 m(2)/g surface area nearly reached the very strong organic pollutant binding capacity of the two magnetic activated carbons, a magnetic biochar with 68 ± 2.8 m(2)/g surface area was the best metal sorbent. Magnetic biochars thus hold promise as more sustainable alternatives to coal-derived magnetic activated carbons.

  5. Carbon dioxide capture process with regenerable sorbents

    DOEpatents

    Pennline, Henry W.; Hoffman, James S.

    2002-05-14

    A process to remove carbon dioxide from a gas stream using a cross-flow, or a moving-bed reactor. In the reactor the gas contacts an active material that is an alkali-metal compound, such as an alkali-metal carbonate, alkali-metal oxide, or alkali-metal hydroxide; or in the alternative, an alkaline-earth metal compound, such as an alkaline-earth metal carbonate, alkaline-earth metal oxide, or alkaline-earth metal hydroxide. The active material can be used by itself or supported on a substrate of carbon, alumina, silica, titania or aluminosilicate. When the active material is an alkali-metal compound, the carbon-dioxide reacts with the metal compound to generate bicarbonate. When the active material is an alkaline-earth metal, the carbon dioxide reacts with the metal compound to generate carbonate. Spent sorbent containing the bicarbonate or carbonate is moved to a second reactor where it is heated or treated with a reducing agent such as, natural gas, methane, carbon monoxide hydrogen, or a synthesis gas comprising of a combination of carbon monoxide and hydrogen. The heat or reducing agent releases carbon dioxide gas and regenerates the active material for use as the sorbent material in the first reactor. New sorbent may be added to the regenerated sorbent prior to subsequent passes in the carbon dioxide removal reactor.

  6. High capacity carbon dioxide sorbent

    DOEpatents

    Dietz, Steven Dean; Alptekin, Gokhan; Jayaraman, Ambalavanan

    2015-09-01

    The present invention provides a sorbent for the removal of carbon dioxide from gas streams, comprising: a CO.sub.2 capacity of at least 9 weight percent when measured at 22.degree. C. and 1 atmosphere; an H.sub.2O capacity of at most 15 weight percent when measured at 25.degree. C. and 1 atmosphere; and an isosteric heat of adsorption of from 5 to 8.5 kilocalories per mole of CO.sub.2. The invention also provides a carbon sorbent in a powder, a granular or a pellet form for the removal of carbon dioxide from gas streams, comprising: a carbon content of at least 90 weight percent; a nitrogen content of at least 1 weight percent; an oxygen content of at most 3 weight percent; a BET surface area from 50 to 2600 m.sup.2/g; and a DFT micropore volume from 0.04 to 0.8 cc/g.

  7. Solid-Phase Extraction of Sulfur Mustard Metabolites Using an Activated Carbon Fiber Sorbent.

    PubMed

    Lee, Jin Young; Lee, Yong Han

    2016-01-01

    A novel solid-phase extraction method using activated carbon fiber (ACF) was developed and validated. ACF has a vast network of pores of varying sizes and microporous structures that result in rapid adsorption and selective extraction of sulfur mustard metabolites according to the pH of eluting solvents. ACF could not only selectively extract thiodiglycol and 1-methylsulfinyl-2-[2-(methylthio)-ethylsulfonyl]ethane eluting a 9:1 ratio of dichloromethane to acetone, and 1,1'-sulfonylbis[2-(methylsulfinyl)ethane] and 1,1'-sulfonylbis- [2-S-(N-acetylcysteinyl)ethane] eluting 3% hydrogen chloride in methanol, but could also eliminate most interference without loss of analytes during the loading and washing steps. A sample preparation method has been optimized for the extraction of sulfur mustard metabolites from human urine using an ACF sorbent. The newly developed extraction method was applied to the trace analysis of metabolites of sulfur mustard in human urine matrices in a confidence-building exercise for the analysis of biomedical samples provided by the Organisation for the Prohibition of Chemical Weapons.

  8. Adsorption of Ammonia on Regenerable Carbon Sorbents

    NASA Technical Reports Server (NTRS)

    Wójtowicz, Marek A.; Cosgrove, Jesph E.; Serio, Michael A..; Wilburn, Monique

    2015-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Data on sorption and desorption of ammonia, which is a major TC of concern, are presented in this paper. The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for ammonia sorption. Ammonia-sorption capacity was related to carbon pore structure characteristics, and the temperature of oxidative carbon-surface treatment was optimized for enhanced ammonia-sorption performance.

  9. Adsorption kinetic and equilibrium study for removal of mercuric chloride by CuCl2-impregnated activated carbon sorbent.

    PubMed

    Li, Xin; Liu, Zhouyang; Lee, Joo-Youp

    2013-05-15

    The intrinsic adsorption kinetics of mercuric chloride (HgCl2) was studied for raw, 4% and 10% CuCl2-impregnated activated carbon (CuCl2-AC) sorbents in a fixed-bed system. An HgCl2 adsorption kinetic model was developed for the AC sorbents by taking into account the adsorption kinetics, equilibrium, and internal and external mass transfer. The adsorption kinetic constants determined from the comparisons between the simulation and experimental results were 0.2, 0.3, and 0.5m(3)/(gs) for DARCO-HG, 4%(wt), and 10%(wt) CuCl2-AC sorbents, respectively, at 140 °C. CuCl2 loading was found to slightly increase the adsorption kinetic constant or at least not to decrease it. The HgCl2 equilibrium adsorption data based on the Langmuir isotherm show that high CuCl2 loading can result in high binding energy of the HgCl2 adsorption onto the carbon surface. The adsorption equilibrium constant was found to increase by ~10 times when CuCl2 loading varied from 0 to 10%(wt), which led to a decrease in the desorption kinetic constant (k2) by ~10 times and subsequently the desorption rate by ~50 times. Intraparticle pore diffusion considered in the model showed good accuracy, allowing for the determination of intrinsic HgCl2 adsorption kinetics.

  10. An X-ray photoelectron spectroscopy study of surface changes on brominated and sulfur-treated activated carbon sorbents during mercury capture: performance of pellet versus fiber sorbents.

    PubMed

    Saha, Arindom; Abram, David N; Kuhl, Kendra P; Paradis, Jennifer; Crawford, Jenni L; Sasmaz, Erdem; Chang, Ramsay; Jaramillo, Thomas F; Wilcox, Jennifer

    2013-12-03

    This work explores surface changes and the Hg capture performance of brominated activated carbon (AC) pellets, sulfur-treated AC pellets, and sulfur-treated AC fibers upon exposure to simulated Powder River Basin-fired flue gas. Hg breakthrough curves yielded specific Hg capture amounts by means of the breakthrough shapes and times for the three samples. The brominated AC pellets showed a sharp breakthrough after 170-180 h and a capacity of 585 μg of Hg/g, the sulfur-treated AC pellets exhibited a gradual breakthrough after 80-90 h and a capacity of 661 μg of Hg/g, and the sulfur-treated AC fibers showed no breakthrough even after 1400 h, exhibiting a capacity of >9700 μg of Hg/g. X-ray photoelectron spectroscopy was used to analyze sorbent surfaces before and after testing to show important changes in quantification and oxidation states of surface Br, N, and S after exposure to the simulated flue gas. For the brominated and sulfur-treated AC pellet samples, the amount of surface-bound Br and reduced sulfur groups decreased upon Hg capture testing, while the level of weaker Hg-binding surface S(VI) and N species (perhaps as NH4(+)) increased significantly. A high initial concentration of strong Hg-binding reduced sulfur groups on the surface of the sulfur-treated AC fiber is likely responsible for this sorbent's minimal accumulation of S(VI) species during exposure to the simulated flue gas and is linked to its superior Hg capture performance compared to that of the brominated and sulfur-treated AC pellet samples.

  11. Study the properties of activated carbon and oxyhydroxide aluminum as sorbents for removal humic substances from natural waters

    NASA Astrophysics Data System (ADS)

    Shiyan, L. N.; Machekhina, K. I.; Gryaznova, E. N.

    2016-02-01

    The present work relates to the problem of high-quality drinking water supply using processes of adsorption on activated carbon and aluminum oxyhydroxide for removal humic- type organic substances. Also the paper reports on sorbtion properties of the activeted carbon Norit SA UF and oxyhydroxide aluminum for removal humic substances. It was found out that the maximum adsorption capacity of activated carbon to organic substances is equal to 0.25 mg/mg and aluminum oxyhydroxide is equal to 0.3 mg/mg. It is shown that the maximum adsorption capacity of activated carbon Norit SA UF to iron (III) ions is equal to 0.0045 mg/mg and to silicon ions is equal to 0.024 mg/mg. Consequently, the aluminum oxyhydroxide has better adsorption characteristics in comparison with the activated carbon for removal of humic substances, iron and silicon ions. It is associated with the fact that activated carbon has a large adsorption surface, and this is due to its porous structure, but not all molecules can enter into these pores. Therefore, the fibrous structure of aluminum oxyhydroxide promotes better sorption capacity. The presented results suggest that activated carbon Norit SA UF and aluminum oxyhydroxide can be used as sorbents for removal humic substances or other organic substances from groundwater and natural waters.

  12. The antimicrobial efficiency of silver activated sorbents

    NASA Astrophysics Data System (ADS)

    Đolić, Maja B.; Rajaković-Ognjanović, Vladana N.; Štrbac, Svetlana B.; Rakočević, Zlatko Lj.; Veljović, Đorđe N.; Dimitrijević, Suzana I.; Rajaković, Ljubinka V.

    2015-12-01

    This study is focused on the surface modifications of the materials that are used for antimicrobial water treatment. Sorbents of different origin were activated by Ag+-ions. The selection of the most appropriate materials and the most effective activation agents was done according to the results of the sorption and desorption kinetic studies. Sorption capacities of selected sorbents: granulated activated carbon (GAC), zeolite (Z), and titanium dioxide (T), activated by Ag+-ions were following: 42.06, 13.51 and 17.53 mg/g, respectively. The antimicrobial activity of Ag/Z, Ag/GAC and Ag/T sorbents were tested against Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus and yeast C. albicans. After 15 min of exposure period, the highest cell removal was obtained using Ag/Z against S. aureus and E. coli, 98.8 and 93.5%, respectively. Yeast cell inactivation was unsatisfactory for all three activated sorbents. The antimicrobial pathway of the activated sorbents has been examined by two separate tests - Ag+-ions desorbed from the activated surface to the aqueous phase and microbial cell removal caused by the Ag+-ions from the solid phase (activated surface sites). The results indicated that disinfection process significantly depended on the microbial-activated sites interactions on the modified surface. The chemical state of the activating agent had crucial impact to the inhibition rate. The characterization of the native and modified sorbents was performed by X-ray diffraction technique, X-ray photoelectron spectroscopy and scanning electron microscope. The concentration of adsorbed and released ions was determined by inductively coupled plasma optical emission spectroscopy and mass spectrometry. The antimicrobial efficiency of activated sorbents was related not only to the concentration of the activating agent, but moreover on the surface characteristics of the material, which affects the distribution and the accessibility of the activating agent.

  13. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Ya Liang; Douglas P. Harrison

    2003-01-01

    The objective of this project is to develop a simple and inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates or intermediate salts through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests suggested that high calcination temperatures decrease the activity of sodium bicarbonate Grade 1 (SBC No.1) during subsequent carbonation cycles, but there is little or no progressive decrease in activity in successive cycles. SBC No.1 appears to be more active than SBC No.3. As expected, the presence of SO{sub 2} in simulated flue gas results in a progressive loss of sorbent capacity with increasing cycles. This is most likely due to an irreversible reaction to produce Na{sub 2}SO{sub 3}. This compound appears to be stable at calcination temperatures as high as 200 C. Tests of 40% supported potassium carbonate sorbent and plain support material suggest that some of the activity observed in tests of the supported sorbent may be due to adsorption by the support material rather than to carbonation of the sorbent.

  14. Pd/activated carbon sorbents for mid-temperature capture of mercury from coal-derived fuel gas.

    PubMed

    Li, Dekui; Han, Jieru; Han, Lina; Wang, Jiancheng; Chang, Liping

    2014-07-01

    Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great importance. Based on the very excellent Hg removal ability of Pd and the high adsorption abilities of activated carbon (AC) for H₂S and Hg, a series of Pd/AC sorbents was prepared by using pore volume impregnation, and their performance in capturing Hg and H₂S from coal-derived fuel gas was investigated using a laboratory-scale fixed-bed reactor. The effects of loading amount, reaction temperature and reaction atmosphere on Hg removal from coal-derived fuel gas were studied. The sorbents were characterized by N₂ adsorption, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicated that the efficiency of Hg removal increased with the increasing of Pd loading amount, but the effective utilization rate of the active component Pd decreased significantly at the same time. High temperature had a negative influence on the Hg removal. The efficiency of Hg removal in the N₂-H₂S-H₂-CO-Hg atmosphere (simulated coal gas) was higher than that in N₂-H₂S-Hg and N₂-Hg atmospheres, which showed that H₂ and CO, with their reducing capacity, could benefit promote the removal of Hg. The XPS results suggested that there were two different ways of capturing Hg over sorbents in N₂-H₂S-Hg and N₂-Hg atmospheres.

  15. Encapsulated liquid sorbents for carbon dioxide capture.

    PubMed

    Vericella, John J; Baker, Sarah E; Stolaroff, Joshuah K; Duoss, Eric B; Hardin, James O; Lewicki, James; Glogowski, Elizabeth; Floyd, William C; Valdez, Carlos A; Smith, William L; Satcher, Joe H; Bourcier, William L; Spadaccini, Christopher M; Lewis, Jennifer A; Aines, Roger D

    2015-02-05

    Drawbacks of current carbon dioxide capture methods include corrosivity, evaporative losses and fouling. Separating the capture solvent from infrastructure and effluent gases via microencapsulation provides possible solutions to these issues. Here we report carbon capture materials that may enable low-cost and energy-efficient capture of carbon dioxide from flue gas. Polymer microcapsules composed of liquid carbonate cores and highly permeable silicone shells are produced by microfluidic assembly. This motif couples the capacity and selectivity of liquid sorbents with high surface area to facilitate rapid and controlled carbon dioxide uptake and release over repeated cycles. While mass transport across the capsule shell is slightly lower relative to neat liquid sorbents, the surface area enhancement gained via encapsulation provides an order-of-magnitude increase in carbon dioxide absorption rates for a given sorbent mass. The microcapsules are stable under typical industrial operating conditions and may be used in supported packing and fluidized beds for large-scale carbon capture.

  16. Potential hazards of brominated carbon sorbents for mercury emission control.

    PubMed

    Bisson, Teresa M; Xu, Zhenghe

    2015-02-17

    Mercury is a toxic air pollutant, emitted from the combustion of coal. Activated Carbon (AC) or other carbon sorbent (CS) injection into coal combustion flue gases can remove elemental mercury through an adsorption process. Recently, a brominated CS with biomass ash as the carbon source (Br-Ash) was developed as an alternative for costly AC-based sorbent for mercury capture. After mercury capture, these sorbents are disposed in landfill, and the stability of bromine and captured mercury is of paramount importance. The objective of this study is to determine the fate of mercury and bromine from Br-Ash and brominated AC after their service. Mercury and bromine leaching tests were conducted using the standard toxicity characteristic leaching procedure (TCLP). The mercury was found to be stable on both the Br-Ash and commercial brominated AC sorbents, while the bromine leached into the aqueous phase considerably. Mercury pulse injection tests on the sorbent material after leaching indicate that both sorbents retain significant mercury capture capability even after the majority of bromine was removed. Testing of the Br-Ash sorbent over a wider range of pH and liquid:solid ratios resulted in leaching of <5% of mercury adsorbed on the Br-Ash. XPS analysis indicated more organically bound Br and less metal-Br bonds after leaching.

  17. Activated carbons from end-products of tree nut and tree fruit production as sorbents for removing methyl bromide in ventilation effluent from postharvest chamber fumigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    End-products of tree nuts and tree fruits grown in California, USA were evaluated for the ability to remove methyl bromide from the ventilation effluent of postharvest chamber fumigations. Activated carbon sorbents from walnut and almond shells as well as peach and prune pits were prepared using dif...

  18. Magnetic graphene oxide-polystyrene and magnetic activated carbon-polystyrene nanocomposites as sorbents for bisphenol A.

    NASA Astrophysics Data System (ADS)

    Rekos, Kyriazis; Kampouraki, Zoi Christina; Samanidou, Victoria; Deliyanni, Eleni

    2016-04-01

    Magnetic graphene oxide-polystyrene and magnetic activated carbon-polystyrene nanocomposites as sorbents for bisphenol A. Kyriazis Rekos1, Zoi Christina Kampouraki1, Victoria Samanidou2, Eleni Deliyanni1 1 Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece 2 Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece The aim of this work was to prepare and characterize novel composites of magnetic activated carbon or magnetic graphene oxide with polystyrene (GO/PSm), through one step simple and effective route. Μagnetite nanoparticles, prepared in the laboratory, were dispersed in the presence of activated carbon (C) or graphene oxide (GO) in a polystyrene (PS) solution in dimethylformamide, at elevated temperature, for the fabrication of the magnetite-Carbon-PS (C-PSm) and magnetite- Graphene Oxide-PS (GO-PSm) hybrid-nanoparticles. For comparison, C-PS and GO-PS composites were also prepared in the same route. The nanocomposites were tested for their sorption ability for an endocrine disruptor, bisphenol A. The effect of solution pH, initial concentration, contact time and temperature were examined. The magnetic graphite oxide-polystyrene presented higher adsorption capacity (100 mg/g) than the non magnetic composites (70 mg/g), as well as than initial graphite oxide (20 mg/g). FTIR, XRD, BET, TGA, VSM and SEM were performed in order to investigate the role of the PS on the better adsorption performance of the mGO-PS nanocomposites. The characterization with these techniques revealed the possible interactions of the surface functional groups of activated carbon and/or graphite oxide with polystyrene that resulted in the better performance of the magnetic nanocomposites for bisphenol A adsorption.

  19. Sorbent carbon development Task 5.2

    SciTech Connect

    Timpe, R.C.

    1995-11-01

    The primary objective of this study is to transform low-rank coals (LRCs) into effective sorbent carbons economically for gas- and liquid-phase contaminant removal. The work carried out in this project primarily involved -12 x +30-mesh North Dakota leonardite or lignite, a highly oxygenated LRC. The ash content of the Georesources leonardite, the principal char source, was significantly higher than expected. Reduction of ash content was partially accomplished by grinding the coal and preparing the activated carbon from the -12 x 30-mesh fraction. Preliminary carbon preparation testing was carried out on the small thermogravimetric analyzer (TGA). The sample was carbonized at one temperature (250{degrees}, 350{degrees}, 480{degrees} or 550{degrees}C) under inert gas for selected time, then activated at a higher temperature (700{degree}-1000{degrees}C) under inert or reactive gas for a selected time, then cooled. The resulting carbon was characterized by SO{sub 2} adsorption at ambient temperature or 100{degrees}C. The activated chars prepared on a larger scale was characterized using the following: TGA proximate analysis; SO{sub 2} sorption at ambient temperature; iodine number; BET surface area; and porosity.

  20. Double-bed-type extraction needle packed with activated-carbon-based sorbents for very volatile organic compounds.

    PubMed

    Ueta, Ikuo; Samsudin, Emi Liana; Mizuguchi, Ayako; Takeuchi, Hayato; Shinki, Takumi; Kawakubo, Susumu; Saito, Yoshihiro

    2014-01-01

    A novel needle-type sample preparation device was developed for the determination of very volatile organic compounds (VVOCs) in gaseous samples by gas chromatography-mass spectrometry (GC-MS). Two types of activated-carbon-based sorbents, Carbopack X and a carbon molecular sieve (CMS), were investigated as the extraction medium. A double-bed-type extraction needle showed successful extraction and desorption performance for all investigated VVOCs, including acetaldehyde, isoprene, pentane, acetone, and ethanol. Sensitive and reliable determination of VVOCs was achieved by systematically optimizing several desorption conditions. In addition, the effects of sample humidity on the extraction and desorption of analytes were investigated with the needle-type extraction devices. Only the CMS packed extraction needle was adversely affected by sample humidity during the desorption process; on the other hand the double-bed-type extraction needle was unaffected by sample humidity. Finally, the developed double-bed-type extraction needle was successfully applied to the analysis of breath VVOCs of healthy subjects.

  1. Carbon Dioxide Capture from Flue Gas Using Dry Regenerable Sorbents

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Thomas Nelson; Santosh Gangwal; Ya Liang; Tyler Moore; Margaret Williams; Douglas P. Harrison

    2004-09-30

    Laboratory studies were conducted to investigate dry, regenerable, alkali carbonate-based sorbents for the capture of CO{sub 2} from power plant flue gas. Electrobalance, fixed-bed and fluid-bed reactors were used to examine both the CO{sub 2} capture and sorbent regeneration phases of the process. Sodium carbonate-based sorbents (calcined sodium bicarbonate and calcined trona) were the primary focus of the testing. Supported sodium carbonate and potassium carbonate sorbents were also tested. Sodium carbonate reacts with CO{sub 2} and water vapor contained in flue gas at temperatures between 60 and 80 C to form sodium bicarbonate, or an intermediate salt (Wegscheider's salt). Thermal regeneration of this sorbent produces an off-gas containing equal molar quantities of CO{sub 2} and H{sub 2}O. The low temperature range in which the carbonation reaction takes place is suited to treatment of coal-derived flue gases following wet flue gas desulfurization processes, but limits the concentration of water vapor which is an essential reactant in the carbonation reaction. Sorbent regeneration in an atmosphere of CO{sub 2} and water vapor can be carried out at a temperature of 160 C or higher. Pure CO{sub 2} suitable for use or sequestration is available after condensation of the H{sub 2}O. Flue gas contaminants such as SO{sub 2} react irreversibly with the sorbent so that upstream desulfurization will be required when sulfur-containing fossil fuels are used. Approximately 90% CO{sub 2} capture from a simulated flue gas was achieved during the early stages of fixed-bed reactor tests using a nominal carbonation temperature of 60 C. Effectively complete sorbent carbonation is possible when the fixed-bed test is carried out to completion. No decrease in sorbent activity was noted in a 15-cycle test using the above carbonation conditions coupled with regeneration in pure CO{sub 2} at 160 C. Fluidized-bed reactor tests of up to five cycles were conducted. Carbonation of sodium

  2. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Thomas Nelson

    2004-11-01

    Laboratory studies were conducted to investigate dry, regenerable, alkali carbonate-based sorbents for the capture of CO{sub 2} from power plant flue gas. Electrobalance, fixed-bed and fluid-bed reactors were used to examine both the CO{sub 2} capture and sorbent regeneration phases of the process. Sodium carbonate-based sorbents (calcined sodium bicarbonate and calcined trona) were the primary focus of the testing. Supported sodium carbonate and potassium carbonate sorbents were also tested. Sodium carbonate reacts with CO{sub 2} and water vapor contained in flue gas at temperatures between 60 and 80 C to form sodium bicarbonate, or an intermediate salt (Wegscheider's salt). Thermal regeneration of this sorbent produces an off-gas containing equal molar quantities of CO{sub 2} and H{sub 2}O. The low temperature range in which the carbonation reaction takes place is suited to treatment of coal-derived flue gases following wet flue gas desulfurization processes, but limits the concentration of water vapor which is an essential reactant in the carbonation reaction. Sorbent regeneration in an atmosphere of CO{sub 2} and water vapor can be carried out at a temperature of 160 C or higher. Pure CO{sub 2} suitable for use or sequestration is available after condensation of the H{sub 2}O. Flue gas contaminants such as SO{sub 2} react irreversibly with the sorbent so that upstream desulfurization will be required when sulfur-containing fossil fuels are used. Approximately 90% CO{sub 2} capture from a simulated flue gas was achieved during the early stages of fixed-bed reactor tests using a nominal carbonation temperature of 60 C. Effectively complete sorbent carbonation is possible when the fixed-bed test is carried out to completion. No decrease in sorbent activity was noted in a 15-cycle test using the above carbonation conditions coupled with regeneration in pure CO{sub 2} at 160 C. Fluidized-bed reactor tests of up to five cycles were conducted. Carbonation of sodium

  3. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Ya Liang; Tyler Moore; Douglas P. Harrison

    2003-08-01

    This report describes research conducted between April 1, 2003 and June 30, 2003 on the use of dry regenerable sorbents for concentration of carbon dioxide from flue gas. Grade 1 sodium bicarbonate performed similarly to grade 5 sodium bicarbonate in fixed bed testing in that activity improved after the first carbonation cycle and did not decline over the course of 5 cycles. Thermogravimetric analysis indicated that sodium bicarbonate sorbents produced by calcination of sodium bicarbonate are superior to either soda ash or calcined trona. Energy requirements for regeneration of carbon dioxide sorbents (either wet or dry) is of primary importance in establishing the economic feasibility of carbon dioxide capture processes. Recent studies of liquid amine sorption processes were reviewed and found to incorporate conflicting assumptions of energy requirements. Dry sodium based processes have the potential to be less energy intensive and thus less expensive than oxygen inhibited amine based systems. For dry supported sorbents, maximizing the active fraction of the sorbent is of primary importance in developing an economically feasible process.

  4. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Raghubir P. Gupta; William J. McMichael; Douglas P. Harrison; Ya Liang

    2002-01-01

    The objective of this project is to develop a simple, inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbent being used in this project is sodium carbonate which is converted to sodium bicarbonate, or ''baking soda,'' through reaction with carbon dioxide and water vapor. Sodium bicarbonate is regenerated to sodium carbonate when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, five cycle thermogravimetric tests were conducted at the Louisiana State University (LSU) with sodium bicarbonate Grade 3 (SBC{number_sign}3) which showed that carbonation activity declined slightly over 5 cycles following severe calcination conditions of 200 C in pure CO{sub 2}. Three different sets of calcination conditions were tested. Initial carbonation activity (as measured by extent of reaction in the first 25 minutes) was greatest subsequent to calcination at 120 C in He, slightly less subsequent to calcination in 80% CO{sub 2}/20% H{sub 2}O, and lowest subsequent to calcination in pure CO{sub 2} at 200 C. Differences in the extent of reaction after 150 minutes of carbonation, subsequent to calcination under the same conditions followed the same trend but were less significant. The differences between fractional carbonation under the three calcination conditions declined with increasing cycles. A preliminary fixed bed reactor test was also conducted at LSU. Following calcination, the sorbent removed approximately 19% of the CO{sub 2} in the simulated flue gas. CO{sub 2} evolved during subsequent calcination was consistent with an extent of carbonation of approximately 49%. Following successful testing of SBC{number_sign}3 sorbent at RTI reported in the last quarter, a two cycle fluidized bed reactor test was conducted with trona as the sorbent precursor, which was calcined to sodium carbonate. In the first carbonation cycle, CO

  5. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Raghubir P. Gupta; William J. McMichael; Douglas P. Harrison; Ya Liang

    2002-04-01

    The objective of this project is to develop a simple, inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates, through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests conducted at LSU indicated that exposure of sorbent to water vapor prior to contact with carbonation gas does not significantly increase the reaction rate. Calcined fine mesh trona has a greater initial carbonation rate than calcined sodium bicarbonate, but appears to be more susceptible to loss of reactivity under severe calcination conditions. The Davison attrition indices for Grade 5 sodium bicarbonate, commercial grade sodium carbonate and extra fine granular potassium carbonate were, as tested, outside of the range suitable for entrained bed reactor testing. Fluidized bed testing at RTI indicated that in the initial stages of reaction potassium carbonate removed 35% of the carbon dioxide in simulated flue gas, and is reactive at higher temperatures than sodium carbonate. Removals declined to 6% when 54% of the capacity of the sorbent was exhausted. Carbonation data from electrobalance testing was correlated using a shrinking core reaction model. The activation energy of the reaction of sodium carbonate with carbon dioxide and water vapor was determined from nonisothermal thermogravimetry.

  6. Developing Polycation-Clay Sorbents for Efficient Filtration of Diclofenac: Effect of Dissolved Organic Matter and Comparison to Activated Carbon.

    PubMed

    Kohay, Hagay; Izbitski, Avital; Mishael, Yael G

    2015-08-04

    The presence of nanoconcentrations of persistent pharmaceuticals in treated wastewater effluent and in surface water has been frequently reported. A novel organic-inorganic hybrid sorbent based on adsorbing quarternized poly vinylpyridinium-co-styrene (QPVPcS) to montmorillonite (MMT) was designed for the removal of the anionic micropollutants. QPVPcS-clay composites were characterized by X-ray diffraction, FTIR, thermal gravimetric analysis, Zeta potential and element analysis. Based on these measurements polymer-clay micro- and nanostructures, as a function of polymer loading, were suggested. The affinity of the anionic pharmaceutical, diclofenac (DCF), to the composite was high and did not decrease dramatically with an increase of ionic strength, indicating that the interactions are not only electrostatic. The presence of humic acid (HA) did not hinder DCF removal by the composite; whereas, its filtration by granulated activated carbon (GAC) was compromised in the presence of HA. The kinetics and adsorption at equilibrium of DCF to the composite and to GAC were measured and modeled by the time dependent Langmuir equation. The adsorption of DCF to the composite was significantly faster than to GAC. Accordingly, the filtration of micro- and nanoconcentrations of DCF by composite columns, in the presence of HA, was more efficient than by GAC columns.

  7. Cheap carbon sorbents produced from lignite by catalytic pyrolysis

    SciTech Connect

    Kuznetsov, B.N.; Schchipko, M.L.

    1995-12-01

    Some data are presented describing the new technology of carbon sorbent production from powdered lignite in the installation with fluidized bed of catalyst. It was shown the different types of char products with extended pore structure and high sorption ability can be produced from cheap and accessible lignite of Kansk-Achinsk coal pit in pilot installation with fluidized bed of Al-Cu-Cr oxide catalyst or catalytically active slag materials. In comparison with the conventional technologies of pyrolysis the catalytic pyrolysis allows to increase by 3-5 times the process productivity and to decrease significantly the formation of harmful compounds. The latter is accomplished by complete oxidation of gaseous pyrolysis products in the presence of catalysts and by avoiding the formation of pyrolysis tars - the source of cancerogenic compounds. The technology of cheap powdered sorbent production from lignites makes possible to obtain from lignite during the time of pyrolysis only a few seconds char products with porosity up to 0.6 cm{sup 3} /g, and specific surface area more than 400 m{sup 3} /g. Some methods of powdered chars molding into carbon materials with the different shape were proved for producing of firmness sorbents. Cheap carbon sorbents obtained by thermocatalytic pyrolysis can be successfully used in purification of different industrial pollutants as one-time sorbent or as adsorbents of long-term application with periodic regeneration.

  8. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Thomas Nelson

    2004-04-01

    This report describes research conducted between January 1, 2004 and March 31, 2004 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas. RTI has produced laboratory scale batches (approximately 300 grams) of supported sorbents (composed of 20 to 40% sodium carbonate) with high surface area and acceptable activity. Initial rates of weight gain of the supported sorbents when exposed to a simulated flue gas exceeded that of 100% calcined sodium bicarbonate. One of these sorbents was tested through six cycles of carbonation/calcination by thermogravimetric analysis and found to have consistent carbonation activity. Kinetic modeling of the regeneration cycle on the basis of diffusion resistance at the particle surface is impractical, because the evolving gases have an identical composition to those assumed for the bulk fluidization gas. A kinetic model of the reaction has been developed on the basis of bulk motion of water and carbon dioxide at the particle surface (as opposed to control by gas diffusion). The model will be used to define the operating conditions in future laboratory- and pilot-scale testing.

  9. Sorbents for CO2 capture from high carbon fly ashes.

    PubMed

    Maroto-Valer, M Mercedes; Lu, Zhe; Zhang, Yinzhi; Tang, Zhong

    2008-11-01

    Fly ashes with high-unburned-carbon content, referred to as fly ash carbons, are an increasing problem for the utility industry, since they cannot be marketed as a cement extender and, therefore, have to be disposed. Previous work has explored the potential development of amine-enriched fly ash carbons for CO2 capture. However, their performance was lower than that of commercially available sorbents, probably because the samples investigated were not activated prior to impregnation and, therefore, had a very low surface area. Accordingly, the work described here focuses on the development of activated fly ash derived sorbents for CO2 capture. The samples were steam activated at 850 degrees C, resulting in a significant increase of the surface area (1075 m2/g). The activated samples were impregnated with different amine compounds, and the resultant samples were tested for CO2 capture at different temperatures. The CO2 adsorption of the parent and activated samples is typical of a physical adsorption process. The impregnation process results in a decrease of the surface areas, indicating a blocking of the porosity. The highest adsorption capacity at 30 and 70 degrees C for the amine impregnated activated carbons was probably due to a combination of physical adsorption inherent from the parent sample and chemical adsorption of the loaded amine groups. The CO2 adsorption capacities for the activated amine impregnated samples are higher than those previously published for fly ash carbons without activation (68.6 vs. 45 mg CO2/g sorbent).

  10. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P.Gupta; William J. McMichael; Ya Liang; Douglas P. Harrison

    2002-10-01

    The objective of this project is to develop a simple and inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests suggested that higher temperature calcination of trona leds to reduced carbonation activity in subsequent cycles, but that calcination in dry carbon dioxide did not result in decreased activity relative to calcination in helium. Following higher temperature calcination, sodium bicarbonate (SBC) No.3 has greater activity than either coarse or fine grades of trona. Fixed bed testing of calcined SBC No.3 at 70 C confirmed that high rates of carbon dioxide absorption are possible and that the resulting product is a mixture of Wegscheider's salt and sodium carbonate. In fluidized bed testing of supported potassium carbonate, very rapid carbonation rates were observed. Activity of the support material complicated the data analysis. A milled, spherical grade of SBC appeared to be similar in attrition and abrasion characteristics to an unmilled, less regularly shaped SBC. The calcination behavior, at 107 C, for the milled and unmilled materials was also similar.

  11. Layered solid sorbents for carbon dioxide capture

    DOEpatents

    Li, Bingyun; Jiang, Bingbing; Gray, McMahan L; Fauth, Daniel J; Pennline, Henry W; Richards, George A

    2014-11-18

    A solid sorbent for the capture and the transport of carbon dioxide gas is provided having at least one first layer of a positively charged material that is polyethylenimine or poly(allylamine hydrochloride), that captures at least a portion of the gas, and at least one second layer of a negatively charged material that is polystyrenesulfonate or poly(acryclic acid), that transports the gas, wherein the second layer of material is in juxtaposition to, attached to, or crosslinked with the first layer for forming at least one bilayer, and a solid substrate support having a porous surface, wherein one or more of the bilayers is/are deposited on the surface of and/or within the solid substrate. A method of preparing and using the solid sorbent is provided.

  12. Layered solid sorbents for carbon dioxide capture

    SciTech Connect

    Li, Bingyun; Jiang, Bingbing; Gray, McMahan L; Fauth, Daniel J; Pennline, Henry W; Richards, George A

    2013-02-25

    A solid sorbent for the capture and the transport of carbon dioxide gas is provided having at least one first layer of a positively charged material that is polyethylenimine or poly(allylamine hydrochloride), that captures at least a portion of the gas, and at least one second layer of a negatively charged material that is polystyrenesulfonate or poly(acryclic acid), that transports the gas, wherein the second layer of material is in juxtaposition to, attached to, or crosslinked with the first layer for forming at least one bilayer, and a solid substrate support having a porous surface, wherein one or more of the bilayers is/are deposited on the surface of and/or within the solid substrate. A method of preparing and using the solid sorbent is provided.

  13. Nanoporous carbon sorbent for molecular-sieve chromatography of lipoprotein complex

    NASA Astrophysics Data System (ADS)

    Kerimkulova, A. R.; Mansurova, B. B.; Gil'manov, M. K.; Mansurov, Z. A.

    2012-06-01

    The physicochemical characteristics of carbon sorbents are investigated. Electron microscopy data for the sorbent and separated lipoprotein complex are presented. It is found that the obtained carbon sorbent possess high porosity. Nanoporous carbon sorbents for the chromatography of molecular-sieve markers are obtained and tested. The applicability of nanoporous carbon sorbents for separation of lipoprotein complexes (LPC) is investigated.

  14. Engineered nano-magnetic iron oxide-urea-activated carbon nanolayer sorbent for potential removal of uranium (VI) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Mahmoud, Mohamed E.; Khalifa, Mohamed A.; El Wakeel, Yasser M.; Header, Mennatllah S.; Abdel-Fattah, Tarek M.

    2017-04-01

    A novel magnetic nanosorbent was designed using chemical grafting of nano-magnetite (Nano-Fe3O4) with nanolayer of activated carbon (AC) via urea intermediate for the formation of Nano-Fe3O4-Urea-AC. Characterizing was carried out using FT-IR, SEM, HR-TEM, TGA, point of zero charge (Pzc) and surface area analysis. The designed sorbent maintained its magnetic properties and nanosized structure in the range of 8.7-14.1 nm. The surface area was identified as 389 m2/g based on the BET method. Sorption of uranyl ions from aqueous solutions was studied and evaluated in different experimental conditions. Removal of uranyl ions increased with increasing in pH value and the maximum percentage removal was established at pH 5.0. The removal and sorption processes of uranyl ions by Nano-Fe3O4-Urea-AC sorbent were studied and optimized using the batch technique. The key variables affecting removal of uranyl ions were studied including the effect of the contact time, dosage of Nano-Fe3O4-Urea-AC sorbent, reaction temperature, initial uranyl ions concentration and interfering anions and cations.

  15. Adsorption of Carbon Dioxide, Ammonia, Formaldehyde, and Water Vapor on Regenerable Carbon Sorbents

    NASA Technical Reports Server (NTRS)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Wilburn, Monique

    2015-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Furthermore, the current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is nonregenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for simultaneous carbon dioxide, ammonia, formaldehyde, and water sorption. Multiple adsorption/vacuum-regeneration cycles were demonstrated at room temperature, and also the enhancement of formaldehyde sorption by the presence of ammonia in the gas mixture.

  16. Carbon Dioxide Capture from Flue Gas Using Dry Regenerable Sorbents

    SciTech Connect

    Thomas Nelson; David Green; Paul Box; Raghubir Gupta; Gennar Henningsen

    2007-06-30

    Regenerable sorbents based on sodium carbonate (Na{sub 2}CO{sub 3}) can be used to separate carbon dioxide (CO{sub 2}) from coal-fired power plant flue gas. Upon thermal regeneration and condensation of water vapor, CO{sub 2} is released in a concentrated form that is suitable for reuse or sequestration. During the research project described in this report, the technical feasibility and economic viability of a thermal-swing CO{sub 2} separation process based on dry, regenerable, carbonate sorbents was confirmed. This process was designated as RTI's Dry Carbonate Process. RTI tested the Dry Carbonate Process through various research phases including thermogravimetric analysis (TGA); bench-scale fixed-bed, bench-scale fluidized-bed, bench-scale co-current downflow reactor testing; pilot-scale entrained-bed testing; and bench-scale demonstration testing with actual coal-fired flue gas. All phases of testing showed the feasibility of the process to capture greater than 90% of the CO{sub 2} present in coal-fired flue gas. Attrition-resistant sorbents were developed, and these sorbents were found to retain their CO{sub 2} removal activity through multiple cycles of adsorption and regeneration. The sodium carbonate-based sorbents developed by RTI react with CO{sub 2} and water vapor at temperatures below 80 C to form sodium bicarbonate (NaHCO3) and/or Wegscheider's salt. This reaction is reversed at temperatures greater than 120 C to release an equimolar mixture of CO{sub 2} and water vapor. After condensation of the water, a pure CO{sub 2} stream can be obtained. TGA testing showed that the Na{sub 2}CO3 sorbents react irreversibly with sulfur dioxide (SO{sub 2}) and hydrogen chloride (HCl) (at the operating conditions for this process). Trace levels of these contaminants are expected to be present in desulfurized flue gas. The sorbents did not collect detectable quantities of mercury (Hg). A process was designed for the Na{sub 2}CO{sub 3}-based sorbent that includes a co

  17. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Thomas Nelson; Raghubir P. Gupta

    2005-01-01

    This report describes research conducted between October 1, 2004 and December 31, 2004 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas. Two supported sorbents were tested in a bench scale fluidized bed reactor system. The sorbents were prepared by impregnation of sodium carbonate on to an inert support at a commercial catalyst manufacturing facility. One sorbent, tested through five cycles of carbon dioxide sorption in an atmosphere of 3% water vapor and 0.8 to 3% carbon dioxide showed consistent reactivity with sodium carbonate utilization of 7 to 14%. A second, similarly prepared material, showed comparable reactivity in one cycle of testing. Batches of 5 other materials were prepared in laboratory scale quantities (primarily by spray drying). These materials generally have significantly greater surface areas than calcined sodium bicarbonate. Small scale testing showed no significant adsorption of mercury on representative carbon dioxide sorbent materials under expected flue gas conditions.

  18. Carbon Dioxide Capture from Flue Gas Using Dry, Regenerable Sorbents

    SciTech Connect

    David A. Green; Thomas O. Nelson; Brian S. Turk; Paul D. Box Raghubir P. Gupta

    2006-09-30

    This report describes research conducted between July 1, 2006 and September 30, 2006 on the use of dry regenerable sorbents for removal of carbon dioxide (CO{sub 2}) from coal combustion flue gas. Modifications to the integrated absorber/ sorbent regenerator/ sorbent cooler system were made to improve sorbent flow consistency and measurement reliability. Operation of the screw conveyor regenerator to achieve a sorbent temperature of at least 120 C at the regenerator outlet is necessary for satisfactory carbon dioxide capture efficiencies in succeeding absorption cycles. Carbon dioxide capture economics in new power plants can be improved by incorporating increased capacity boilers, efficient flue gas desulfurization systems and provisions for withdrawal of sorbent regeneration steam in the design.

  19. Activated carbons from end-products of tree nut and tree fruit production as sorbents for removing methyl bromide in ventilation effluent following postharvest chamber fumigation.

    PubMed

    Hall, Wiley A; Bellamy, David E; Walse, Spencer S

    2015-04-01

    End-products of tree nuts and tree fruits grown in California, USA were evaluated for the ability to remove methyl bromide (MB) from ventilation effluent following postharvest chamber fumigation. Activated carbon sorbents from walnut and almond shells as well as peach and prune pits were prepared using different methods of pyrolysis, activation, and quenching. Each source and preparation was evaluated for yield from starting material (%, m/m) and performance on tests where MB-containing airstreams were directed through a columnar bed of the activated carbon in an experimental apparatus, termed a parallel adsorbent column tester, which was constructed as a scaled-down model of a chamber ventilation system. We report the number of doses needed to first observe the breakthrough of MB downstream of the bed and the capacity of the activated carbon for MB (%, m/m) based on a fractional percentage of MB mass sorbed at breakthrough relative to mass of the bed prior to testing. Results were based on a novel application of solid-phase microextraction with time-weighted averaging sampling of MB concentration in airstreams, which was quantitative across the range of fumigation-relevant conditions and statistically unaffected by relative humidity. Activated carbons from prune pits, prepared either by steam activation or carbon dioxide activation coupled to water quenching, received the greatest number of doses prior to breakthrough and had the highest capacity, approximately 12-14%, outperforming a commercially marketed activated carbon derived from coconut shells. Experimental evidence is presented that links discrepancy in performance to the relative potential for activated carbons to preferentially sorb water vapor relative to MB.

  20. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Raghubir P. Gupta; Douglas P. Harrison; Ya Liang

    2001-10-01

    The objective of this project is to develop a simple, inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbent being used in this project is sodium carbonate which is converted to sodium bicarbonate, ''baking soda,'' through reaction with carbon dioxide and water vapor. Sodium bicarbonate is regenerated to sodium carbonate when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. Testing conducted previously confirmed that the reaction rate and achievable CO{sub 2} capacity of sodium carbonate decreased with increasing temperature, and that the global rate of reaction of sodium carbonate to sodium bicarbonate increased with an increase in both CO{sub 2} and H{sub 2}O concentrations. Energy balance calculations indicated that the rate of heat removal from the particle surface may determine the reaction rate for a particular particle system. This quarter, thermogravimetric analyses (TGA) were conducted which indicated that calcination of sodium bicarbonate at temperatures as high as 200 C did not cause a significant decrease in activity in subsequent carbonation testing. When sodium bicarbonate was subjected to a five cycle calcination/carbonation test, activity declined slightly over the first two cycles but was constant thereafter. TGA tests were also conducted with two other potential sorbents. Potassium carbonate was found to be less active than sodium carbonate, at conditions of interest in preliminary TGA tests. Sodium carbonate monohydrate showed negligible activity. Testing was also conducted in a 2-inch internal diameter quartz fluidized-bed reactor system. A five cycle test demonstrated that initial removals of 10 to 15 percent of the carbon dioxide in a simulated flue gas could be achieved. The carbonation reaction proceeded at temperatures as low as 41 C. Future work by TGA and in fixed-bed, fluidized-bed, and transport

  1. Sorbent Structural Testing on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

    NASA Technical Reports Server (NTRS)

    Watson, David; Knox, James C.; West, Phillip; Bush, Richard

    2016-01-01

    Long term space missions require carbon dioxide removal systems that can function with minimal downtime required for maintenance, low power consumption and maximum efficiency for CO2 removal. A major component of such a system are the sorbents used for the CO2 and desiccant beds. Sorbents must not only have adequate CO2 and H2O removal properties, but they must have the mechanical strength to prevent structural breakdown due to pressure and temperature changes during operation and regeneration, as well as resistance to breakdown due to moisture in the system from cabin air. As part of the studies used to select future CO2 sorbent materials, mechanical tests are performed on various zeolite sorbents to determine mechanical performance while dry and at various humidified states. Tests include single pellet crush, bulk crush and attrition tests. We have established a protocol for testing sorbents under dry and humid conditions, and previously tested the sorbents used on the International Space Station carbon dioxide removal assembly. This paper reports on the testing of a series of commercial sorbents considered as candidates for use on future exploration missions.

  2. Activated carbons from potato peels: The role of activation agent and carbonization temperature of biomass on their use as sorbents for bisphenol A uptake from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Arampatzidou, An; Deliyanni, Eleni A.

    2015-04-01

    Activated carbons prepared from potato peels, a solid waste by product, and activated with different activating chemicals, have been studied for the adsorption of an endocrine disruptor (Bisphenol-A) from aqueous solutions. The potato peels biomass was activated with phosphoric acid, KOH and ZnCl2. The different activating chemicals were tested in order the better activation agent to be found. The carbons were carbonized by pyrolysis, in one step procedure, at three different temperatures in order the role of the temperature of carbonization to be pointed out. The porous texture and the surface chemistry of the prepared activated carbons were characterized by Nitrogen adsorption (BET), Scanning Electron Microscope (SEM), thermal analysis (DTA) and Fourier Transform Infrared Spectroscopy (FTIR). Batch experiments were performed to investigate the effect of pH, the adsorbent dose, the initial bisphenol A concentration and temperature. Equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherms. The thermodynamic parameters such as the change of enthalpy (ΔH0), entropy (ΔS0) and Gibb's free energy (ΔG0) of adsorption systems were also evaluated. The adsorption capacity calculated from the Langmuir isotherm was found to be 450 mg g-1 at an initial pH 3 at 25 °C for the phosphoric acid activated carbon, that make the activated carbon a promising adsorbent material.

  3. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Thomas Nelson

    2004-07-01

    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.

  4. Carbon Dioxide Capture from Flue Gas Using Dry, Regenerable Sorbents

    SciTech Connect

    David A. Green; Thomas O. Nelson; Brian S. Turk; Paul D. Box; Andreas Weber; Raghubir P. Gupta

    2006-01-01

    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.

  5. Carbon Dioxide Capture from Flue Gas Using Dry, Regenerable Sorbents

    SciTech Connect

    David A. Green; Thomas Nelson; Brian S. Turk; Paul Box; Raghubir P. Gupta

    2005-10-01

    This report describes research conducted between July 1, 2005, and September 30, 2005, on the use of dry regenerable sorbents for removal of carbon dioxide (CO{sub 2}) from flue gas from coal combustion. A new batch of supported sorbent containing 10% sodium carbonate (Na{sub 2}CO{sub 3}) was obtained and characterized. Thermogravimetric analysis (TGA) testing confirmed that the Na{sub 2}CO{sub 3} sorbent reacted with sulfur dioxide (SO{sub 2}) at temperatures between 40 and 160 C. Although the rate of reaction was more rapid at lower temperatures, these data suggest that SO{sub 2} will not be released from the sorbent under expected sorbent-regeneration conditions. Preliminary work has been conducted to establish the design specifications for a laboratory screw-conveyor sorbent regeneration/cooling apparatus. A plan for a scheduled pilot-scale test of a heated hollow-screw conveyor was developed. This test will be conducted at facilities of the screw conveyor fabricator. This test will confirm the extent of sorbent regeneration and will provide data to evaluate multi-cycle sorbent attrition rates associated with this type of processing.

  6. Carbon Dioxide Capture from Flue Gas Using Dry, Regenerable Sorbents

    SciTech Connect

    David A. Green; Thomas O. Nelson; Brian S. Turk; Paul D. Box; Raghubir P. Gupta

    2006-03-31

    This report describes research conducted between January 1, 2006, and March 31, 2006, on the use of dry regenerable sorbents for removal of carbon dioxide (CO{sub 2}) from coal combustion flue gas. An integrated system composed of a downflow co-current contact absorber and two hollow screw conveyors (regenerator and cooler) was assembled, instrumented, debugged, and calibrated. A new batch of supported sorbent containing 15% sodium carbonate was prepared and subjected to surface area and compact bulk density determination.

  7. SORPTION OF MERCURY SPECIES BY ACTIVATED CARBONS AND CALCIUM-BASES SORBENTS: EFFECT OF TEMPERATURE, MERCURY CONCENTRATION AND ACID GASES

    EPA Science Inventory

    Bench-scale studies of mercury/sorbent reactions were conducted to understand mechanistic limitations of field-scale attempts to reduce emissions of mercury from combustion processes. The effects of temperature (60 - 140 degrees C), sulfur dioxide (SO2, 1000 ppm ), hydrogen chlor...

  8. Use of sorbents of hot-contact coal carbonization in the power industry

    SciTech Connect

    A.I. Blokhin; F.E. Keneman; A.V. Sklyarov; B.S. Fedoseev

    2003-11-15

    The many years of experience in the use of sorbents of hot-contact coal carbonization (HCCC) in the power industry is used for substantiation of their prospects for solving problems of power and materials saving and improving the reliability and safety of operation of power equipment. Results of tests of sorbents in systems of water conditioning of thermal power plants, cleaning of return condensates, mazut- and oil-contaminated process wastewaters, makeup water in heat networks, and biosorption cleaning of sewerage are presented. The sorption methods of cleaning are shown to have many advantages, to save expensive ion-exchange resins and reagents, to decrease the cost of desalinated water, and to prolong the service of power equipment. Comparative data are presented for basic commercial kinds of activated carbon and HCCC (sorbents activated crushed brown-coal coke (ABD)). The technical characteristics of sorbents of hot-contact coal carbonization are shown to be at the level of commercial sorbents or be higher at a much lower cost (by a factor of 2.5 - 3). It is shown that the creation of several HCCC installations with an output of 25 - 30 thousand tons of sorbents a year at coal-fired power plants will solve many water-cleaning problems of the 'EES Rossii' Co. ('The United Power Systems of Russia') and make it a monopolistic producer of activated carbon in the Russian market.

  9. CATALYTIC EFFECTS OF CARBON SORBENTS FOR MERCURY CAPTURE. (R827649C001)

    EPA Science Inventory

    Activated carbon sorbents have the potential to be an effective means of mercury control in combustion systems. Reactions of activated carbons in flow systems with mercury and gas stream components were investigated to determine the types of chemical interactions that occur on...

  10. Use of Sorbents of Hot-Contact Coal Carbonization in the Power Industry

    SciTech Connect

    Blokhin, A. I.; Keneman, F. E.; Sklyarov, A. V.; Fedoseev, B. S.

    2003-11-15

    The many years of experience in the use of sorbents of hot-contact coal carbonization in the power industry is used for substantiation of their prospects for solving problems of power and materials saving and improving the reliability and safety of operation of power equipment. Results of tests of sorbents in systems of water conditioning of thermal power plants, cleaning of return condensates, mazut- and oil-contaminated process wastewaters, makeup water in heat networks, and biosorption cleaning of sewerage are presented. The sorption methods of cleaning are shown to have many advantages, to save expensive ion-exchange resins and reagents, to decrease the cost of desalinated water, and to prolong the service of power equipment. Comparative data are presented for basic commercial kinds of activated carbon and HCCC sorbents (ABD). The technical characteristics of sorbents of hot-contact coal carbonization are shown to be at the level of commercial sorbents or be higher at a much lower cost (by a factor of 2.5 - 3). It is shown that the creation of several HCCC installations with an output of 25 - 30 thousand tons of sorbents a year at coal-fired power plants will solve many water-cleaning problems of the 'EES Rossii' Co. ('The United Power Systems of Russia') and make it a monopolistic producer of activated carbon in the Russian market.

  11. Effects of HCl and SO{sub 2} concentration on mercury removal by activated carbon sorbents in coal-derived flue gas

    SciTech Connect

    Ryota Ochiai; M. Azhar Uddin; Eiji Sasaoka; Shengji Wu

    2009-09-15

    The effect of the presence of HCl and SO{sub 2} in the simulated coal combustion flue gas on the Hg{sup 0} removal by a commercial activated carbon (coconut shell AC) was investigated in a laboratory-scale fixed-bed reactor in a temperature range of 80-200{sup o}C. The characteristics (thermal stability) of the mercury species formed on the sorbents under various adsorption conditions were investigated by the temperature-programmed decomposition desorption (TPDD) technique. It was found that the presence of HCl and SO{sub 2} in the flue gas affected the mercury removal efficiency of the sorbents as well as the characteristics of the mercury adsorption species. The mercury removal rate of AC increased with the HCl concentration in the flue gas. In the presence of HCl and the absence of SO{sub 2} during Hg{sup 0} adsorption by AC, a single Hg{sup 0} desorption peak at around 300{sup o}C was observed in the TPDD spectra and intensity of this peak increased with the HCl concentration during mercury adsorption. The peak at around 300{sup o}C may be derived from the decomposition and desorption of mercury chloride species. The presence of SO{sub 2} during mercury adsorption had an adverse effect on the mercury removal by AC in the presence of HCl. In the presence of both HCl and SO{sub 2} during Hg{sup 0} adsorption by AC, the major TPDD peak temperatures changed drastically depending upon the concentration of HCl and SO{sub 2} in flue gas during Hg{sup 0} adsorption. 16 refs., 7 figs.

  12. Carbon-Based Regenerable Sorbents for the Combined Carbon Dioxide and Ammonia Removal for the Primary Life Support System (PLSS)

    NASA Technical Reports Server (NTRS)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Manthina, Venkata; Singh, Prabhakar; Chullen, Cinda

    2014-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs). Since ammonia is the most important TC to be captured, data on TC sorption presented in this paper are limited to ammonia, with results relevant to other TCs to be reported at a later time. The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Furthermore, the current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. The objective of this study was to demonstrate the feasibility of using carbon sorbents for the reversible, concurrent sorption of carbon dioxide and ammonia. Several carbon sorbents were fabricated and tested, and multiple adsorption/vacuum-regeneration cycles were demonstrated at room temperature, and also a carbon surface conditioning technique that enhances the combined carbon dioxide and ammonia sorption without impairing sorbent regeneration.

  13. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Raghubir P. Gupta; Alejandro Lopez-Ortiz; Douglas P. Harrison; Ya Liang

    2001-07-01

    Sodium based sorbents including sodium carbonate may be used to capture carbon dioxide from flue gas. A relatively concentrated carbon dioxide stream may be recoverable for sequestration when the sorbent is regenerated. Electrobalance tests indicated that sodium carbonate monohydrate was formed in a mixture of helium and water vapor at temperatures below 65 C. Additional compounds may also form, but this could not be confirmed. In the presence of carbon dioxide and water vapor, both the initial reaction rate of sodium carbonate with carbon dioxide and water and the sorbent capacity decreased with increasing temperature, consistent with the results from the previous quarter. Increasing the carbon dioxide concentration at constant temperature and water vapor concentration produced a measurable increase in rate, as did increasing the water vapor concentration at constant carbon dioxide concentration and temperature. Runs conducted with a flatter TGA pan resulted in a higher initial reaction rate, presumably due to improved gas-solid contact, but after a short time, there was no significant difference in the rates measured with the different pans. Analyses of kinetic data suggest that the surface of the sodium carbonate particles may be much hotter than the bulk gas due to the highly exothermic reaction with carbon dioxide and water, and that the rate of heat removal from the particle may control the reaction rate. A material and energy balance was developed for a cyclic carbonation/calcination process which captures about 26 percent of the carbon dioxide present in flue gas available at 250 C.

  14. Preparation of gold- and chlorine-impregnated bead-type activated carbon for a mercury sorbent trap.

    PubMed

    Song, Young Cheol; Lee, Tai Gyu

    2016-12-01

    This study aimed to develop a mercury (Hg) adsorption trap, which can be used to measure the concentration of elemental Hg in emissions from a Hg discharge facility, and evaluate its adsorption efficiency. The Hg spiking efficiency was compared by impregnating metallic and halogen materials that have high affinity for Hg into activated carbon (AC) to determine an accurate spiking method for Hg on AC. The Hg spiking efficiency was compared according to the type and content of the impregnated substances. AC impregnated with Cl and Au had a 15-20% higher Hg spiking efficiency compared to virgin AC. For Au impregnation at weight ratios of 0-20 wt% of adsorbent, spiking efficiencies of over 97% were observed under certain conditions. The Hg adsorption properties of the above adsorbent were determined experimentally, and the results were used to test the adsorption performance of Hg adsorption traps.

  15. Magnesian calcite sorbent for carbon dioxide capture.

    PubMed

    Mabry, James C; Mondal, Kanchan

    2011-01-01

    Magnesian calcite with controlled properties was synthesized for the removal of carbon dioxide. The results from characterization, reactivity and CO2 capture capacity for different synthesis conditions are reported. The magnesian calcite samples (CaCO3:MgCO3) were synthesized by the coprecipitation of specific amounts of commercially available CaO and MgO by carbon dioxide. Characterization was done with BET, SEM/EDS, particle size analysis and XRD. The capacity was measured using TGA cycles at 800 degrees C and compared for different preparation conditions. The effects of CaO, MgO and surfactant loading on the physical properties and carbonation activity were studied to determine the optimal synthesis condition. A long-term carbonation-calcination cycling test was conducted on the optimal sample. It was observed that the sample maintained its capacity to 86% of its original uptake even after 50 cycles.

  16. Characterization of calcium carbonate sorbent particle in furnace environment.

    PubMed

    Lee, Kang Soo; Jung, Jae Hee; Keel, Sang In; Yun, Jin Han; Min, Tai Jin; Kim, Sang Soo

    2012-07-01

    The oxy-fuel combustion system is a promising technology to control CO₂ and NO(x) emissions. Furthermore, sulfation reaction mechanism under CO₂-rich atmospheric condition in a furnace may lead to in-furnace desulfurization. In the present study, we evaluated characteristics of calcium carbonate (CaCO₃) sorbent particles under different atmospheric conditions. To examine the physical/chemical characteristics of CaCO₃, which is used as a sorbent particle for in-furnace desulfurization in the oxy-fuel combustion system, they were injected into high temperature drop tube furnace (DTF). Experiments were conducted at varying temperatures, residence times, and atmospheric conditions in a reactor. To evaluate the aerosolizing characteristics of the CaCO₃ sorbent particle, changes in the size distribution and total particle concentration between the DTF inlet and outlet were measured. Structural changes (e.g., porosity, grain size, and morphology) of the calcined sorbent particles were estimated by BET/BJH, XRD, and SEM analyses. It was shown that sorbent particles rapidly calcined and sintered in the air atmosphere, whereas calcination was delayed in the CO₂ atmosphere due to the higher CO₂ partial pressure. Instead, the sintering effect was dominant in the CO₂ atmosphere early in the reaction. Based on the SEM images, it was shown that the reactions of sorbent particles could be explained as a grain-subgrain structure model in both the air and CO₂ atmospheres.

  17. Carbon sorbents and management of contaminated sediments: there are two sides to every story

    NASA Astrophysics Data System (ADS)

    Akkanen, Jarkko; Nybom, Inna; Abel, Sebastian

    2014-05-01

    Controlling the bioavailability of chemicals with different type of sorbents in contaminated sediments has been quickly developed to be a considerable choice for remediation. Especially in the case of neutral lipophilic organic chemicals, carbon based materials such as activated carbon has shown to be promising in reducing the exposure of benthic organisms. The efficiency to reduce contaminant bioavailability appears to be chemical congener, sorbent dose and type specific. Sediment characteristics play a role too. In addition to these beneficial effects, there are also secondary implications, which can be manifested in adverse effects in the sediment-dwelling organisms. Similarly with the capacity of sorbent to bind the target contaminants the magnitude of the secondary effects appears to be sediment, organism and sorbent specific. Thus, sorbent properties such as sorption capacity and particle size are important. In addition, less selective sediment feeders are more susceptible to these adverse effects and the effects are stronger in sediments being less suitable as habitat for the organisms. It has to be noted that in sediments that are acutely toxic the amendments can improve well-being of the organisms. The mechanisms of these adverse effects are still partly unclear, but there are indications that reduction of nutrient availability can be one. In addition, other mechanisms can be also discussed. Therefore, the usage of sorbents for remediation purposes requires case specific assessments for to evaluate both positive and negative effects, which is naturally that needs to be done regardless of the remediation method.

  18. Sorbents for mercury removal from flue gas

    SciTech Connect

    Granite, Evan J.; Hargis, Richard A.; Pennline, Henry W.

    1998-01-01

    A review of the various promoters and sorbents examined for the removal of mercury from flue gas is presented. Commercial sorbent processes are described along with the chemistry of the various sorbent-mercury interactions. Novel sorbents for removing mercury from flue gas are suggested. Since activated carbons are expensive, alternate sorbents and/or improved activated carbons are needed. Because of their lower cost, sorbent development work can focus on base metal oxides and halides. Additionally, the long-term sequestration of the mercury on the sorbent needs to be addressed. Contacting methods between the flue gas and the sorbent also merit investigation.

  19. Predicting sorption of organic acids to a wide range of carbonized sorbents

    NASA Astrophysics Data System (ADS)

    Sigmund, Gabriel; Kah, Melanie; Sun, Huichao; Hofmann, Thilo

    2016-04-01

    Many contaminants and infochemicals are organic acids that undergo dissociation under environmental conditions. The sorption of dissociated anions to biochar and other carbonized sorbents is typically lower than that of neutral species. It is driven by complex processes that are not yet fully understood. It is known that predictive approaches developed for neutral compounds are unlikely to be suitable for organic acids, due to the effects of dissociation on sorption. Previous studies on the sorption of organic acids to soils have demonstrated that log Dow, which describes the decrease in hydrophobicity of acids upon dissociation, is a useful alternative to log Kow. The aim of the present study was to adapt a log Dow based approach to describe the sorption of organic acids to carbonized sorbents. Batch experiments were performed with a series of 9 sorbents (i.e., carbonized wood shavings, pig manure, and sewage sludge, carbon nanotubes and activated carbon), and four acids commonly used for pesticidal and biocidal purposes (i.e., 2,4-D, MCPA, 2,4-DB, and triclosan). Sorbents were comprehensively characterized, including by N2 and CO2 physisorption, Fourier transform infrared spectroscopy, and elemental analysis. The wide range of sorbents considered allows (i) discussing the mechanisms driving the sorption of neutral and anionic species to biochar, and (ii) their dependency on sorbate and sorbent properties. Results showed that the sorption of the four acids was influenced by factors that are usually not considered for neutral compounds (i.e., pH, ionic strength). Dissociation affected the sorption of the four compounds, and sorption of the anions ranged over five orders of magnitude, thus substantially contributing to sorption in some cases. For prediction purposes, most of the variation in sorption to carbonized sorbents (89%) could be well described with a two-parameter regression equation including log Dow and sorbent specific surface area. The proposed model

  20. From carbon nanostructures to high-performance sorbents for chromatographic separation and preconcentration

    NASA Astrophysics Data System (ADS)

    Postnov, V. N.; Rodinkov, O. V.; Moskvin, L. N.; Novikov, A. G.; Bugaichenko, A. S.; Krokhina, O. A.

    2016-02-01

    Information on carbon nanostructures (fullerenes, nanotubes, graphene, nanodiamond and nanodispersed active carbon) used to develop high-performance sorbents of organics and heavy metal ions from aqueous solutions is collected and analyzed. The advantages in the synthesis of hybrid carbon nanostructures and the possibilities of surface modification of these systems in order to carry out fast sorption pre-concentration are considered. Prospects for application of these materials in sorption technologies and analytical chemistry are discussed. The bibliography includes 364 references.

  1. Tail-end Hg capture on Au/carbon-monolith regenerable sorbents.

    PubMed

    Izquierdo, M Teresa; Ballestero, Diego; Juan, Roberto; García-Díez, Enrique; Rubio, Begoña; Ruiz, Carmen; Pino, M Rosa

    2011-10-15

    In this work, a regenerable sorbent for Hg retention based on carbon supported Au nanoparticles has been developed and tested. Honeycomb structures were chosen in order to avoid pressure drop and particle entrainment in a fixed bed. Carbon-based supports were selected in order to easily modify the surface chemistry to favour the Au dispersion. Results of Hg retention and regeneration were obtained in a bench scale experimental installation working at high space velocities (for sorbent, 53,000 h(-1); for active phase, 2.6 × 10(8) h(-1)), 120 °C for retention temperature and Hg inlet concentration of 23 ppbv. Gold nanoparticles were shown to be the active phase for mercury capture through an amalgamating mechanism. The mercury captured by the spent sorbent can be easily released to be disposed or reused. Mercury evolution from spent sorbents was followed by TPD experiments showing that the sorbent can be regenerated at temperatures as low as 220 °C.

  2. Desulfurization sorbent development activities at METC

    SciTech Connect

    Siriwardane, R.V.

    1995-06-01

    Development of a suitable regenerable sorbent is a major barrier issue in the hot gas cleanup program for integrated gasification combined-cycle (IGCC) systems. This has been a challenging problem during the last 20 years, since many of the sorbents developed in the program could not retain their reactivity and physical integrity during repeated cycles of sulfidation and regeneration reactions. A series of promising sorbents (METC 2-10), which were capable of sustaining their reactivity and physical integrity during repeated sulfidation/ regeneration cycles, have been developed at the Morgantown Energy Technology Center (METC). These sorbents were tested both in low-pressure (260 KPa/23 psig) and high-pressure (520 KPa/60.7 psig) fixed-bed reactors at 538{degrees}C (1000{degrees}F) with simulated coal gas. High-pressure testing was continued for 20 cycles with steam regeneration. A major research goal during the last year was to lower the cost of materials utilized during the sorbent preparation. The METC 9 sorbent was prepared by substituting low-cost materials for some of the materials in METC 6 sorbent. The sulfur capacity of the two sorbents were similar during the 20-cycle testing. METC 2 sorbent was exposed to coal gas in the Modular Gas Cleanup Rig and it was later tested in the high-pressure fixed-bed reactor. The reactivity of the METC 2 sorbent was unaffected by the exposure to the coal gas. Development of these sorbents will be continued for both fluid-bed and moving-bed applications.

  3. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Raghubir Gupta; Alejandro Lopez-Ortiz

    2001-01-01

    Four grades of sodium bicarbonate and two grades of trona were characterized in terms of particle size distribution, surface area, pore size distribution, and attrition. Surface area and pore size distribution determinations were conducted after calcination of the materials. The sorbent materials were subjected to thermogravimetric testing to determine comparative rates and extent of calcination (in inert gas) and sorption (in a simulated coal combustion flue gas mixture). Selected materials were exposed to five calcination/sorption cycles and showed no decrease in either sorption capacity or sorption rate. Process simulations were conducted involving different heat recovery schemes. The process is thermodynamically feasible. The sodium-based materials appear to have suitable physical properties for use as regenerable sorbents and, based on thermogravimetric testing, are likely to have sorption and calcination rates that are rapid enough to be of interest in full-scale carbon sequestration processes.

  4. Moisture swing sorbent for carbon dioxide capture from ambient air.

    PubMed

    Wang, Tao; Lackner, Klaus S; Wright, Allen

    2011-08-01

    An amine-based anion exchange resin dispersed in a flat sheet of polypropylene was prepared in alkaline forms so that it would capture carbon dioxide from air. The resin, with quaternary ammonium cations attached to the polymer structure and hydroxide or carbonate groups as mobile counterions, absorbs carbon dioxide when dry and releases it when wet. In ambient air, the moist resin dries spontaneously and subsequently absorbs carbon dioxide. This constitutes a moisture induced cycle, which stands in contrast to thermal pressure swing based cycles. This paper aims to determine the isothermal performance of the sorbent during such a moisture swing. Equilibrium experiments show that the absorption and desorption process can be described well by a Langmuir isothermal model. The equilibrium partial pressure of carbon dioxide over the resin at a given loading state can be increased by 2 orders of magnitude by wetting the resin.

  5. Sorbent Structural Impacts Due to Humidity on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

    NASA Technical Reports Server (NTRS)

    Watson, David; Knox, James C.; West, Phillip; Stanley, Christine M.; Bush, Richard

    2015-01-01

    The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The CO2 removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort encompasses structural stability testing of existing and emerging sorbents. Testing will be performed on dry sorbents and sorbents that have been conditioned to three humidity levels. This paper describes the sorbent structural stability screening efforts in support of the LSS Project within the AES Program.

  6. Investigation and Demonstration of Dry Carbon-Based Sorbent Injection for Mercury Control

    SciTech Connect

    Jim Butz; Terry Hunt

    2005-11-01

    Public Service Company of Colorado and ADA Technologies, Inc. have performed a study of the injection of activated carbon for the removal of vapor-phase mercury from coal-fired flue gas streams. The project was completed under contract to the US Department of Energy's National Energy Technology Laboratory, with contributions from EPRI and Public Service Company. The prime contractor for the project was Public Service Company, with ADA Technologies as the major subcontractor providing technical support to all aspects of the project. The research and development effort was conducted in two phases. In Phase I a pilot facility was fabricated and tests were performed using dry carbon-based sorbent injection for mercury control on a coal-fired flue gas slipstream extracted from an operating power plant. Phase II was designed to move carbon injection technology towards commercial application on coal-fired power plants by addressing key reliability and operability concerns. Phase II field work included further development work with the Phase I pilot and mercury measurements on several of PSCo's coal-fired generating units. In addition, tests were run on collected sorbent plus fly ash to evaluate the impact of the activated carbon sorbent on the disposal of fly ash. An economic analysis was performed where pilot plant test data was used to develop a model to predict estimated costs of mercury removal from plants burning western coals. Testing in the pilot plant was undertaken to quantify the effects of plant configuration, flue gas temperature, and activated carbon injection rate on mercury removal. All three variables were found to significantly impact the mercury removal efficiency in the pilot. The trends were clear: mercury removal rates increased with decreasing flue gas temperature and with increasing carbon injection rates. Mercury removal was much more efficient with reverse-gas and pulse-jet baghouse configurations than with an ESP as the particulate control device

  7. Aerogel sorbents

    DOEpatents

    Begag, Redouane; Rhine, Wendell E; Dong, Wenting

    2016-04-05

    The current invention describes methods and compositions of various sorbents based on aerogels of various silanes and their use as sorbent for carbon dioxide. Methods further provide for optimizing the compositions to increase the stability of the sorbents for prolonged use as carbon dioxide capture matrices.

  8. Screening of carbon-based sorbents for the removal of elemental mercury from simulated combustion flue gas

    SciTech Connect

    Young, B.C.; Musich, M.A.

    1995-12-31

    A fixed-bed reactor system with continuous Hg{sup 0} analysis capabilities was used to evaluate commercial carbon sorbents for the removal of elemental mercury from simulated flue gas. The objectives of the program were to compare the sorbent effectiveness under identical test conditions and to identify the effects of various flue gas components on elemental mercury sorption. Sorbents tested included steam-activated lignite, chemically activated hardwood, chemically activated bituminous coal, iodated steam-activated coconut shell, and sulfur-impregnated steam-activated bituminous coal. The iodated carbon was the most effective sorbent, showing over 99% mercury removal according to U.S. Environmental Protection Agency (EPA) Method 101A. Data indicate that adding O{sub 2} at 4 vol% reduced the effectiveness of the steam-activated lignite, chemically activated hardwood, and sulfur- impregnated steam-activated bituminous coal. Adding SO{sub 2} at 500 ppm improved the mercury removal of the sulfur-impregnated carbon. Further, the presence of HCl gas (at 50 ppm) produced an order of magnitude increase in mercury removal with the chemically activated and sulfur-impregnated bituminous coal-based carbons.

  9. Methane preconcentration in a microtrap using multiwalled carbon nanotubes as sorbents.

    PubMed

    Saridara, Chutarat; Ragunath, Smruti; Pu, Yong; Mitra, Somenath

    2010-09-10

    The GC monitoring of green house gases is a challenging task because the concentration of organic species such as methane are relatively low (ppm to ppb) and their analysis requires some level of preconcentration. Since methane is highly volatile, it is not easily retained on conventional sorbents. In this paper we present multiwalled carbon nanotubes (MWNTs) as an effective sorbent for a microtrap designed for methane preconcentration. Its performance was compared to other commercially available carbon based sorbents, and it was found to be the most effective sorbent in terms of breakthrough volume and enthalpy of adsorption.

  10. Regenerable immobilized aminosilane sorbents for carbon dioxide capture applications

    DOEpatents

    Gay, McMahan; Choi, Sunho; Jones, Christopher W

    2014-09-16

    A method for the separation of carbon dioxide from ambient air and flue gases is provided wherein a phase separating moiety with a second moiety are simultaneously coupled and bonded onto an inert substrate to create a mixture which is subsequently contacted with flue gases or ambient air. The phase-separating moiety is an amine whereas the second moiety is an aminosilane, or a Group 4 propoxide such as titanium (IV) propoxide (tetrapropyl orthotitanate, C.sub.12H.sub.28O.sub.4Ti). The second moiety makes the phase-separating moiety insoluble in the pores of the inert substrate. The new sorbents have a high carbon dioxide loading capacity and considerable stability over hundreds of cycles. The synthesis method is readily scalable for commercial and industrial production.

  11. Modified Activated Carbon Prepared from Acorn Shells as a New Solid-Phase Extraction Sorbent for the Preconcentration and Determination of Trace Amounts of Nickel in Food Samples Prior to Flame Atomic Absorption Spectrometry.

    PubMed

    Ebrahimi, Bahram

    2017-03-01

    A new solid-phase extraction (SPE) sorbent was introduced based on acidic-modified (AM) activated carbon (AC) prepared from acorn shells of native oak trees in Kurdistan. Hydrochloric acid (15%, w/w) and nitric acid (32.5%, w/w) were used to condition and modify AC. The IR spectra of AC and AM-AC showed that AM lead to the formation of increasing numbers of acidic functional groups on AM-AC. AM-AC was used in the SPE method for the extraction and preconcentration of Ni+2 prior to flame atomic absorption spectrometric determination at ng/mL levels in model and real food samples. Effective parameters of the SPE procedure, such as the pH of the solutions, sorbent dosage, extraction time, sample volume, type of eluent, and matrix ions, were considered and optimized. An enrichment factor of 140 was obtained. The calibration curve was linear with an R2 of 0.997 in the concentration range of 1-220 ng/mL. The RSD was 5.67% (for n = 7), the LOD was 0.352 ng/mL, and relative recoveries in vegetable samples ranged from 96.7 to 103.7%.

  12. A calcium oxide sorbent process for bulk separation of carbon dioxide

    SciTech Connect

    Harrison, D.P.; Han, C.

    1994-10-01

    In this experimental investigation, a laboratory-scale fixed-bed reactor containing a calcium-based sorbent is being used to study the feasibility of combining CO{sub 2} removal with the water gas shift reaction. The sorptive properties of the calcium oxide sorbent were studied as a function of carbonation temperature and pressure, synthesis gas composition, reactor space velocity, and sorbent composition and properties.

  13. Magnetic solid-phase extraction using carbon nanotubes as sorbents: a review.

    PubMed

    Herrero-Latorre, C; Barciela-García, J; García-Martín, S; Peña-Crecente, R M; Otárola-Jiménez, J

    2015-09-10

    Magnetic solid-phase extraction (M-SPE) is a procedure based on the use of magnetic sorbents for the separation and preconcentration of different organic and inorganic analytes from large sample volumes. The magnetic sorbent is added to the sample solution and the target analyte is adsorbed onto the surface of the magnetic sorbent particles (M-SPs). Analyte-M-SPs are separated from the sample solution by applying an external magnetic field and, after elution with the appropriate solvent, the recovered analyte is analyzed. This approach has several advantages over traditional solid phase extraction as it avoids time-consuming and tedious on-column SPE procedures and it provides a rapid and simple analyte separation that avoids the need for centrifugation or filtration steps. As a consequence, in the past few years a great deal of research has been focused on M-SPE, including the development of new sorbents and novel automation strategies. In recent years, the use of magnetic carbon nanotubes (M-CNTs) as a sorption substrate in M-SPE has become an active area of research. These materials have exceptional mechanical, electrical, optical and magnetic properties and they also have an extremely large surface area and varied possibilities for functionalization. This review covers the synthesis of M-CNTs and the different approaches for the use of these compounds in M-SPE. The performance, general characteristics and applications of M-SPE based on magnetic carbon nanotubes for organic and inorganic analysis have been evaluated on the basis of more than 110 references. Finally, some important challenges with respect the use of magnetic carbon nanotubes in M-SPE are discussed.

  14. Co-Adsorption of Ammonia and Formaldehyde on Regenerable Carbon Sorbents for the Primary Life Support System (PLSS)

    NASA Technical Reports Server (NTRS)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Wilburn, Monique S.

    2016-01-01

    Results are presented on the development of a reversible carbon sorbent for trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is deemed non-regenerable, while the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. Data on concurrent sorption and desorption of ammonia and formaldehyde, which are major TCs of concern, are presented in this paper. A carbon sorbent was fabricated by dry impregnation of a reticulated carbon-foam support with polyvinylidene chloride, followed by carbonization and thermal oxidation in air. Sorbent performance was tested for ammonia and formaldehyde sorption and vacuum regeneration, with and without water present in the gas stream. It was found that humidity in the gas phase enhanced ammonia-sorption capacity by a factor larger than two. Co-adsorption of ammonia and formaldehyde in the presence of water resulted in strong formaldehyde sorption (to the point that it was difficult to saturate the sorbent on the time scales used in this study). In the absence of humidity, adsorption of formaldehyde on the carbon surface was found to impair ammonia sorption in subsequent runs; in the presence of water, however, both ammonia and formaldehyde could be efficiently removed from the gas phase by the sorbent. The efficiency of vacuum regeneration could be enhanced by gentle heating to temperatures below 60 deg.

  15. Sorbents for the oxidation and removal of mercury

    DOEpatents

    Olson, Edwin S; Holmes, Michael J; Pavlish, John Henry

    2013-08-20

    A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

  16. Sorbents for the oxidation and removal of mercury

    DOEpatents

    Olson, Edwin S.; Holmes, Michael J.; Pavlish, John Henry

    2014-09-02

    A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

  17. Sorbents for the oxidation and removal of mercury

    DOEpatents

    Olson, Edwin S.; Holmes, Michael J.; Pavlish, John H.

    2008-10-14

    A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

  18. Sorbents for the oxidation and removal of mercury

    DOEpatents

    Olson, Edwin S [Grand Forks, ND; Holmes, Michael J [Thompson, ND; Pavlish, John H [East Grand Forks, MN

    2012-05-01

    A promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams. The sorbent comprises a new modified carbon form containing reactive forms of halogen and halides. Optional components may be added to increase reactivity and mercury capacity. These may be added directly with the sorbent, or to the flue gas to enhance sorbent performance and/or mercury capture. Mercury removal efficiencies obtained exceed conventional methods. The sorbent can be regenerated and reused. Sorbent treatment and preparation methods are also described. New methods for in-flight preparation, introduction, and control of the active sorbent into the mercury contaminated gas stream are described.

  19. Thermal activation of CaO-based sorbent and self-reactivation during CO{sub 2} capture looping cycles

    SciTech Connect

    Vasilije Manovic; Edward J. Anthony

    2008-06-01

    In this study, the thermal activation of different types of CaO-based sorbents was examined. Pretreatments were performed at different temperatures (800-1300{sup o}C) and different durations (6-48 h) using four Canadian limestones. Sieved fractions of the limestones, powders obtained by grinding, and hydroxides produced following multiple carbonation/calcination cycles achieved in a tube furnace were examined. Pretreated samples were evaluated using two types of thermogravimetric reactors/analyzers. The most important result was that thermal pretreatment could improve sorbent performance. In comparison to the original, pretreated sorbents showed better conversions over a longer series of CO{sub 2} cycles. Moreover, in some cases, sorbent activity actually increased with cycle number, and this effect was especially pronounced for powdered samples preheated at 1000{sup o}C. In these experiments, the increase of conversion with cycle number (designated as self-reactivation) after 30 cycles produced samples that were about 50% carbonated for the four sorbents examined here, and there appeared to be the potential for additional increase. These results were explained with the newly proposed pore-skeleton model. This model suggests, in addition to changes in the porous structure of the sorbent, that changes in the pore-skeleton produced during pretreatment strongly influence subsequent carbonation/calcination cycles. 31 refs., 8 figs.

  20. Screening of carbon-based sorbents for the removal of elemental mercury from simulated combustion flue gas

    SciTech Connect

    Young, B.C.; Musich, M.A.

    1995-12-31

    A fixed-bed reactor system with continuous Hg{sup 0} analysis capabilities was used to evaluate commercial carbon sorbents for the removal of elemental mercury from simulated flue gas. The objectives of the program were to compare the sorbent effectiveness under identical test conditions and to identify the effects of various flue gas components on elemental mercury sorption. Sorbents tested included steam-activated lignite, chemical-activated hardwood and bituminous coal, iodated steam-activated coconut shell, and sulfur-impregnated steam-activated bituminous coal. The iodated carbon was the most effective carbon, showing over 99% mercury removal according to EPA Method 101A. Data indicate that O{sub 2} (4 vol%) and SO{sub 2} (500 ppm) improved the mercury removal of the other carbons for tests at 150{degrees}C using 100 {mu}g/m{sup 3} Hg{sup 0}. Further, the presence of HCl (at 50 ppm) produced a magnitude increase in mercury removal for the steam-activated and sulfur-impregnated bituminous coal-based carbons.

  1. Catalytically Active Regenerative Sorbent beds (CARS) for airborne contaminants.

    PubMed

    Akse, J R; Thompson, J O

    1995-01-01

    The Pd on Al2O3 catalyst used in the projected Space Station's Trace Contaminant Control System (TCCS) catalytic oxidizer can be poisoned by volatile halogen-, sulfur-, and nitrogen-containing organic species. Catalytically Active Regenerable Sorbents (CARS) eliminate these problematic contaminants and the large carbon bed used for their elimination in a three-step process. Contaminants are conventionally adsorbed by the CARS bed. After saturation, the bed is connected to an off-line recirculation loop, filled with hydrogen, and then heated. At temperature, contaminants are hydrogenated on catalytic sites within the bed, forming simple alkanes and acid gases that are efficiently converted to innocuous salts in an in-line alkaline bed. The CARS bed is regenerated by this cycle and alkane gases are released to be safely oxidized in the catalytic oxidizer. A challenge mixture containing Freon-113, thiophene, trichloroethylene, Halon-1301, and dichloromethane at 1670, 75, 81, 68, and 83 mg/m3 was successfully treated using this technology, demonstrating the CARS feasibility.

  2. Analysis of xylene in aqueous media using needle-trap microextraction with a carbon nanotube sorbent.

    PubMed

    Zeverdegani, Sara Karimi; Bahrami, Abdulrahman; Rismanchian, Masoud; Shahna, Farshid Ghorbani

    2014-07-01

    This paper describes a new extraction technique with needles and a sorbent based on carbon nanotubes to analyze trace amounts of three isomers of xylenes in aqueous samples. In this research, results have been compared with one commercial sorbent. The synthesized sorbent was prepared using sol-gel technology and was packed into 20 gauge needles, and the same size needle was used for packing the commercial sorbent. In the extraction process, a purge and trap sampling methodology is developed, so purging and trapping cycles were performed by a sampling pump. Optimized conditions for standard xylene samples have been obtained, and eight urine samples from workers that were exposed to xylene in the workplace were collected and analyzed. Experimental parameters such as limits of detection and quantification were investigated, and these two parameters were <1 μg/L.

  3. Key factor in rice husk ash/CaO sorbent for high flue gas desulfurization activity

    SciTech Connect

    Irvan Dahlan; Keat Teong Lee; Azlina Harun Kamaruddin; Abdul Rahman Mohamed

    2006-10-01

    Siliceous materials such as rice husk ash (RHA) have potential to be utilized as high performance sorbents for the flue gas desulfurization process in small-scale industrial boilers. This study presents findings on identifying the key factor for high desulfurization activity in sorbents prepared from RHA. Initially, a systematic approach using central composite rotatable design was used to develop a mathematical model that correlates the sorbent preparation variables to the desulfurization activity of the sorbent. The sorbent preparation variables studied are hydration period, x{sub 1} (6-16 h), amount of RHA, x{sub 2} (5-15 g), amount of CaO, x{sub 3} (2-6 g), amount of water, x{sub 4} (90-110 mL), and hydration temperature, x{sub 5} (150-250{sup o}C). The mathematical model developed was subjected to statistical tests and the model is adequate for predicting the SO{sub 2} desulfurization activity of the sorbent within the range of the sorbent preparation variables studied. Based on the model, the amount of RHA, amount of CaO, and hydration period used in the preparation step significantly influenced the desulfurization activity of the sorbent. The ratio of RHA and CaO used in the preparation mixture was also a significant factor that influenced the desulfurization activity of the sorbent. A RHA to CaO ratio of 2.5 leads to the formation of specific reactive species in the sorbent that are believed to be the key factor responsible for high desulfurization activity in the sorbent. Other physical properties of the sorbent such as pore size distribution and surface morphology were found to have insignificant influence on the desulfurization activity of the sorbent. 31 refs., 5 figs., 3 tabs.

  4. Addition of carbon sorbents to reduce PCB and PAH bioavailability in marine sediments: physicochemical tests.

    PubMed

    Zimmerman, John R; Ghosh, Upal; Millward, Rod N; Bridges, Todd S; Luthy, Richard G

    2004-10-15

    The addition of activated carbon as particulate sorbent to the biologically active layer of contaminated sediment is proposed as an in-situ treatment method to reduce the chemical and biological availability of hydrophobic organic contaminants (HOCs) such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). We report results from physicochemical experiments that assess this concept. PCB- and PAH-contaminated sediment from Hunters Point Naval Shipyard, San Francisco Bay, CA, was contacted with coke and activated carbon for periods of 1 and 6 months. Sediment treated with 3.4 wt % activated carbon showed 92% and 84% reductions in aqueous equilibrium PCB and PAH concentrations, 77% and 83% reductions in PCB and PAH uptake by semipermeable membrane devices (SPMD), respectively, and reductions in PCB flux to overlying water in quiescent systems up to 89%. Adding coke to contaminated sediment did not significantly decrease aqueous equilibrium PCB concentrations nor PCB or PAH availability in SPMD measurements. Coke decreased PAH aqueous equilibrium concentrations by 38-64% depending on coke dose and particle size. The greater effectiveness of activated carbon as compared to coke is attributed to its much greater specific surface area and a pore structure favorable for binding contaminants. The results from the physicochemical tests suggest that adding activated carbon to contaminated field sediment reduces HOC availability to the aqueous phase. The benefit is manifested relatively quickly under optimum contact conditions and improves in effectiveness with contact time from 1 to 6 months. Activated carbon application is a potentially attractive method for in-situ, nonremoval treatment of marine sediment contaminated with HOCs.

  5. A new beaded carbon molecular sieve sorbent for 222Rn monitoring.

    PubMed

    Scarpitta, S C

    1996-05-01

    A new commercially available beaded carbon molecular sieve sorbent, Carboxen-564 (20/45 mesh), was tested and compared to Calgon-PCB (40/80) activated carbon for its adsorptive and desorptive characteristics under controlled conditions of temperature (25 degrees C) and relative humidity (RH). The amount of water vapor adsorbed by the beaded carbon molecular sieve material was typically a factor of 4 lower than the activated carbon, with a concomitant fourfold increase in the 222Rn adsorption coefficient, K(Rn). The maximum K(Rn) value for a thin layer of Carboxen-564, following a 2-d exposure at 40% RH, was 7.2 Bq kg(-1) per Bq m(-3). The K(Rn) or a 1-cm bed, following a 2-d exposure was 5.5 Bq m(-3), a 25% reduction. Under dynamic sampling conditions, where 0.4 g of the beaded carbon molecular sieve was contained in a 6 cm x 0.4 cm diameter tube, the maximum K(Rn) value was 6.5 Bq m(-3) after 2.5 h of sampling at 29% RH when the input flow rate was 4.2 x 10(-3) m3 h-1. Kinetic studies were also conducted under passive sampling conditions. The data show that the 222Rn buildup time-constant for a thin layer of the beaded carbon molecular sieve material was 1.3 h, whereas that of a 1 cm bed was 13 h. The 222Rn desorption time-constants, from gram amounts of the beaded carbon molecular sieve material into air and into a commercially available toluene based liquid scintillation cocktail, were 2 h and 3 h, respectively. Carboxen's high 222Rn adsorbing capacity, rapid kinetics, hydrophobicity and physical properties makes it an attractive alternative to other commercially available activated carbon used in passive and dynamic sampling devices.

  6. Carbon capture test unit design and development using amine-based solid sorbent

    SciTech Connect

    Breault, Ronald W.; Spenik, James L.; Shadle, Lawrence J.; Hoffman, James S.; Gray, McMahan L.; Panday, Rupen; Stehle, Richard C.

    2016-06-30

    This study presents the design and development of a reactor system and the subsequent modifications to evaluate an integrated process to scrub carbon dioxide (CO2) from synthetic flue gas using amine based solid sorbents. The paper presents the initial system design and then discusses the various changes implemented to address the change in sorbent from a 180 μm Geldart group B material to a 115 μm Geldart group A material as well as issues discovered during experimental trials where the major obstacle in system operation was the ability to maintain a constant circulation of a solid sorbent stemming from this change in sorbent material. The system primarily consisted of four fluid beds, through which an amine impregnated solid sorbent was circulated and adsorption, pre-heat, regeneration, and cooling processes occurred. Instrumentation was assembled to characterize thermal, hydrodynamic, and gas adsorption performance in this integrated unit. A series of shakedown tests were performed and the configuration altered to meet the needs of the sorbent performance and achieve desired target capture efficiencies. Finally, methods were identified, tested, and applied to continuously monitor critical operating parameters including solids circulation rate, adsorbed and desorbed CO2, solids inventories, and pressures.

  7. INVESTIGATION AND DEMONSTRATION OF DRY CARBON-BASED SORBENT INJECTION FOR MERCURY CONTROL

    SciTech Connect

    Terry Hunt; Mark Fox; Lillian Stan; Sheila Haythornthwaite; Justin Smith; Jason Ruhl

    1998-10-01

    This quarterly report describes the activities that have taken place during the first full quarter of the Phase II project ''Investigation and Demonstration of Dry Carbon-Based Sorbent Injection for Mercury Control''. Modifications were completed and sampling began at the 600 acfm pilot-scale particulate control module (PCM) located at the Comanche Station in Pueblo, CO. The PCM was configured as an electrostatic precipitator for these tests. A Perkin-Elmer flue gas mercury analyzer was installed on-site and operated. Initial test results using both manual sampling methodology and the mercury analyzer are presented herein. Preparations were made during this period for full-scale mercury testing of several PSCo units. A site visit was made to Arapahoe and Cherokee Generating Stations to determine sample locations and to develop a test plan.

  8. Investigation and demonstration of dry carbon-based sorbent injection for mercury control. Quarterly technical report, April 1--June 30, 1996

    SciTech Connect

    Hunt, T.; Sjostrom, S.; Smith, J.; Chang, R.

    1996-07-27

    The overall objective this two phase program is to investigate the use of dry carbon-based sorbents for mercury control. During Phase 1, a bench-scale field test device that can be configured as an electrostatic precipitator, a pulse-jet baghouse, or a reverse-gas baghouse has been designed and will be integrated with an existing pilot-scale facility at PSCo`s Comanche Station. Up to three candidate sorbents will then be injected into the flue gas stream upstream of the test device to determine the mercury removal efficiency for each sorbent. During the Phase 11 effort, component integration for the most promising dry sorbent technology (technically and economically feasible) shall be tested at the 5000 acfm pilot-scale. An extensive work plan has been developed for the project. Three sorbents will be selected for evaluation at the facility through investigation, presentation, and discussion among team members: PSCO, EPRI, ADA, and DOE. The selected sorbents will be tested in the five primary bench-scale configurations: pulse `et baghouse, TOXECON, reverse-gas baghouse, electrostatic precipitator, and an ESP or fabric filter `with no Comanche ash in the flue gas stream. In the EPRI TOXECON system, mercury sorbents will be injected downstream of a primary particulate control device, and collected in a pulse-jet baghouse operated at air-to-cloth ratios of 12 to 16 ft/min, thus separating the mercury and sorbent from the captured flyash. In the no-ash configuration, an external flyash sample will be injected into a clean gas stream to investigate possible variations in sorbent effectiveness in the presence of different ashes. The use of an existing test facility, a versatile design for the test fixture, and installation of a continuous mercury analyzer will allow for the completion of this ambitious test plan. The primary activity during the quarter was to complete fabrication and installation of the facility.

  9. Amine enriched solid sorbents for carbon dioxide capture

    DOEpatents

    Gray, McMahan L.; Soong, Yee; Champagne, Kenneth J.

    2003-04-15

    A new method for making low-cost CO.sub.2 sorbents that can be used in large-scale gas-solid processes. The new method entails treating a solid substrate with acid or base and simultaneous or subsequent treatment with a substituted amine salt. The method eliminates the need for organic solvents and polymeric materials for the preparation of CO.sub.2 capture systems.

  10. Hybrid multiwalled carbon nanotube--Laponite sorbent for removal of methylene blue from aqueous solutions.

    PubMed

    Loginov, Maksym; Lebovka, Nikolai; Vorobiev, Eugene

    2014-10-01

    The article discusses adsorption of methylene blue dye by novel hybrid sorbent consisting of Laponite and multiwalled carbon nanotubes. The sorbent was obtained by sonication of the aqueous suspensions of nanotubes at different concentrations of Laponite. The methods of the methylene blue adsorption, dead-end membrane filtration and environmental scanning electron microscopy were used for the sorbent characterization. It may be concluded from the results of filtration and adsorption experiments that sonication of mixed aqueous suspensions of Laponite and multiwalled carbon nanotubes leads to the formation of hybrid particles (ML-particles) with a core-shell structure. The size and the shape of hybrid particles were determined by nanotubes, while their adsorption properties were determined by Laponite particles attached to the surface of nanotubes. The Laponite content in hybrid particles was corresponding to the Laponite to nanotubes ratio in the initial suspension X(L)=0-1. Due to the presence of Laponite in the sorbent, its adsorbing capacity was much higher as compared to the adsorbing capacity of pure nanotubes, and it was directly proportional to the Laponite content. This sorbent may be used either as a purifying additive or as a filtering layer if it is deposited on the surface of a supporting membrane. Due to relatively large size of hybrid particles, they can be easily separated from the purified solution by filtration or centrifugation.

  11. Mercury removal sorbents

    DOEpatents

    Alptekin, Gokhan

    2016-03-29

    Sorbents and methods of using them for removing mercury from flue gases over a wide range of temperatures are disclosed. Sorbent materials of this invention comprise oxy- or hydroxyl-halogen (chlorides and bromides) of manganese, copper and calcium as the active phase for Hg.sup.0 oxidation, and are dispersed on a high surface porous supports. In addition to the powder activated carbons (PACs), this support material can be comprised of commercial ceramic supports such as silica (SiO.sub.2), alumina (Al.sub.2O.sub.3), zeolites and clays. The support material may also comprise of oxides of various metals such as iron, manganese, and calcium. The non-carbon sorbents of the invention can be easily injected into the flue gas and recovered in the Particulate Control Device (PCD) along with the fly ash without altering the properties of the by-product fly ash enabling its use as a cement additive. Sorbent materials of this invention effectively remove both elemental and oxidized forms of mercury from flue gases and can be used at elevated temperatures. The sorbent combines an oxidation catalyst and a sorbent in the same particle to both oxidize the mercury and then immobilize it.

  12. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    DOEpatents

    Aines, Roger D.

    2013-03-12

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  13. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    DOEpatents

    Aines, Roger D

    2015-03-31

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  14. Determination of dry carbon-based sorbent injection for mercury control in utility ESP and baghouses

    SciTech Connect

    Broderick, T.; Haythornthwaite, S.; Bell, W.; Selegue, T.; Perry, M.

    1998-12-31

    Domestic coal-fired power plants emit approximately 40 to 80 metric tons of mercury to the atmosphere annually. The mercury concentration in utility flue gas is in the dilute range of 0.1 to 1 parts per billion. The EPA is assessing whether such low concentrations of mercury emissions from coal-fired utilities pose any significant health risk and whether mercury regulations would be necessary or appropriate. In anticipation of possible mercury control regulations, ADA Technologies (ADA) and TDA Research, Inc (TDA) were funded by the Department of Energy (DOE) to evaluate carbon-based sorbents for mercury control at utility coal-fired power plants. Past investigations of the use of dry carbon-based sorbent injection for mercury control on pilot-scale utility flue gas applications have shown that these sorbents are capable of removing gas-phase mercury. ADA Technologies field-tested the mercury removal capability of several carbon-based sorbents manufactured by TDA. The test facility was a DOE-owned test facility built and operated by ADA at the Public Service Company of Colorado`s Comanche Station in Pueblo, Colorado. The pilot-scale test fixture is a 600-acfm particulate control module that can be configured as an electrostatic precipitator, a pulse-jet baghouse, or a reverse-gas baghouse. It extracts a slipstream of flue gas from a coal-fired utility boiler. Sorbent is injected into the flue gas slipstream upstream of the particulate control module and is removed by the module. ADA evaluated the mercury capture efficiency of the sorbents over a range of flue gas temperatures and injection rates. In addition, the effect of flyash on mercury capture was also investigated. The test facility is configured to take flue gas from either upstream or downstream of Comanche Station`s full-scale reverse-gas baghouse, allowing tests to be conducted with normal-ash or low-ash flue gas.

  15. Chemical modification of hygroscopic magnesium carbonate into superhydrophobic and oleophilic sorbent suitable for removal of oil spill in water

    NASA Astrophysics Data System (ADS)

    Patowary, Manoj; Ananthakrishnan, Rajakumar; Pathak, Khanindra

    2014-11-01

    The wettability of hygroscopic magnesium carbonate has been modified to develop a superhydrophobic and oleophilic sorbent for oil spill clean-ups via a simple chemical process using palmitic acid. The prepared material was characterized using X-ray diffraction, Fourier transform infra-red spectroscopy, and scanning electron microscopy. Wettability test infers that the sorbent has a static water contact angle of 154 ± 1°, thereby indicating its superhydrophobic character. The sorbent was capable of scavenging oil for about three times its weight, as determined from oil sorption studies, carried out using the sorbent on model oil-water mixture. Interestingly, the chemically modified sorbent has high selectivity, buoyancy, and rate of uptake of oil. Further, the reusability studies confirm the repeatable usage of the sorbent and its efficacy in oil spill remediation.

  16. Carbon dioxide removal system for closed loop atmosphere revitalization, candidate sorbents screening and test results

    NASA Astrophysics Data System (ADS)

    Mattox, E. M.; Knox, J. C.; Bardot, D. M.

    2013-05-01

    Due to the difficulty and expense it costs to resupply manned-spacecraft habitats, a goal is to create a closed loop atmosphere revitalization system, in which precious commodities such as oxygen, carbon dioxide, and water are continuously recycled. Our aim is to test other sorbents for their capacity for future spacecraft missions, such as on the Orion spacecraft, or possibly lunar or Mars mission habitats to see if they would be better than the zeolite sorbents on the 4-bed molecular sieve. Some of the materials being tested are currently used for other industry applications. Studying these sorbents for their specific spacecraft application is different from that for applications on earth because in space, there are certain power, mass, and volume limitations that are not as critical on Earth. In manned-spaceflight missions, the sorbents are exposed to a much lower volume fraction of CO2 (0.6% volume CO2) than on Earth. LiLSX was tested for its CO2 capacity in an atmosphere like that of the ISS. Breakthrough tests were run to establish the capacities of these materials at a partial pressure of CO2 that is seen on the ISS. This paper discusses experimental results from benchmark materials, such as results previously obtained from tests on Grade 522, and the forementioned candidate materials for the Carbon Dioxide Removal Assembly (CDRA) system.

  17. Flue-gas carbon capture on carbonaceous sorbents: Toward a low-cost multifunctional Carbon Filter for 'Green' energy producers

    SciTech Connect

    Radosz, M.; Hu, X.D.; Krutkramelis, K.; Shen, Y.Q.

    2008-05-15

    A low-pressure Carbon Filter Process (patent pending) is proposed to capture carbon dioxide (CO{sub 2}) from flue gas. This filter is filled with a low-cost carbonaceous sorbent, such as activated carbon or charcoal, which has a high affinity (and, hence, high capacity) to CO{sub 2} but not to nitrogen (N{sub 2}). This, in turn, leads to a high CO{sub 2}/N{sub 2} selectivity, especially at low pressures. The Carbon Filter Process proposed in this work can recover at least 90% of flue-gas CO{sub 2} of 90%+ purity at a fraction of the cost normally associated with the conventional amine absorption process. The Carbon Filter Process requires neither expensive materials nor flue-gas compression or refrigeration, and it is easy to heat integrate with an existing or grassroots power plant without affecting the cost of the produced electricity too much. An abundant supply of low-cost CO{sub 2} from electricity producers is good news for enhanced oil recovery (EOR) and enhanced coal-bed methane recovery (ECBMR) operators, because it will lead to higher oil and gas recovery rates in an environmentally sensitive manner. A CO{sub 2}-rich mixture that contains some nitrogen is much less expensive to separate from flue-gas than pure CO{sub 2}; therefore, mixed CO{sub 2}/N{sub 2}-EOR and CO{sub 2}/N{sub 2}-ECBMR methods are proposed to maximize the overall carbon capture and utilization efficiency.

  18. MERCURIC CHLORIDE CAPTURE BY ALKALINE SORBENTS

    EPA Science Inventory

    The paper gives results of bench-scale mechanistic studies of mercury/sorbent reactions that showed that mercuric chloride (HgC12) is readily adsorbed by alkaline sorbents, which may offers a less expensive alternative to the use of activated carbons. A laboratory-scale, fixed-b...

  19. Solid amine compounds as sorbents for carbon dioxide: A concept

    NASA Technical Reports Server (NTRS)

    Sutton, J. G.; Heimlich, P. F.; Tepper, E. H.

    1972-01-01

    Solid amine compounds were examined as possible absorbents for removal of carbon dioxide in life support systems of type which may be employed in high altitude aircraft, spacecraft, or submarines. Many solid amine compounds release absorbed carbon dioxide when heated in vacuum, therefore, when properly packaged spent amine compounds can be readily regenerated and put back into service.

  20. MULTI-PHASE CFD MODELING OF A SOLID SORBENT CARBON CAPTURE SYSTEM

    SciTech Connect

    Ryan, Emily M.; Xu, Wei; DeCroix, David; Saha, Kringan; Huckaby, E. D.; Darteville, Sebastien; Sun, Xin

    2012-05-01

    Post-combustion solid sorbent carbon capture systems are being studied via computational modeling as part of the U.S. Department of Energy’s Carbon Capture Simulation Initiative (CCSI). The work focuses on computational modeling of device-scale multi-phase computational fluid dynamics (CFD) simulations for given carbon capture reactor configurations to predict flow properties, outlet compositions, temperature and pressure. The detailed outputs of the device-scale models provide valuable insight into the operation of new carbon capture devices and will help in the design and optimization of carbon capture systems. As a first step in this project we have focused on modeling a 1 kWe solid sorbent carbon capture system using the commercial CFD software ANSYS FLUENT®. Using the multi-phase models available in ANSYS FLUENT®, we are investigating the use of Eulerian-Eulerian and Eulerian-Lagrangian methods for modeling a fluidized bed carbon capture design. The applicability of the dense discrete phase method (DDPM) is being considered along with the more traditional Eulerian-Eulerian multi-phase model. In this paper we will discuss the design of the 1 kWe solid sorbent system and the setup of the DDPM and Eulerian-Eulerian models used to simulate the system. The results of the hydrodynamics in the system will be discussed and the predictions of the DDPM and Eulerian-Eulerian simulations will be compared. A discussion of the sensitivity of the model to boundary and initial conditions, computational meshing, granular pressure, and drag sub-models will also be presented.

  1. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Raghubir P. Gupta; Alejandro Lopez-Ortiz; Douglas P. Harrison; Ya Liang

    2001-05-01

    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.

  2. High-Performance Sorbents for Carbon Dioxide Capture from Air

    SciTech Connect

    Sholl, David; Jones, Christopher

    2013-03-13

    This project has focused on capture of CO{sub 2} from ambient air (“air capture”). If this process is technically and economically feasible, it could potentially contribute to net reduction of CO{sub 2} emissions in ways that are complementary to better developed techniques for CO{sub 2} from concentrated point sources. We focused on cyclic adsorption processes for CO{sub 2} capture from air in which the entire cycle is performed at moderate temperatures. The project involved both experimental studies of sorbent materials and process level modeling of cyclic air capture processes. In our experimental work, a series of amine-functionalized silica adsorbents were prepared and characterized to determine the impact of molecular architecture on CO{sub 2} capture. Some key findings were: • Amine functionalized silicas can be prepared with high enough CO{sub 2} capacities under ambient conditions to merit consideration for use in air capture processes. • Primary amines are better candidates for CO{sub 2} capture than secondary or tertiary amines, both in terms of amine efficiency for CO{sub 2} adsorption and enhanced water affinity. • Mechanistic understanding of degradation of these materials can enable control of molecular architecture to significantly improve material stability. Our process modeling work provided the first publically available cost and energy estimates for cyclic adsorption processes for air capture of CO{sub 2}. Some key findings were: • Cycles based on diurnal ambient heating and cooling cannot yield useful purities or amounts of captured CO{sub 2}. • Cycles based on steam desorption at 110 oC can yield CO{sub 2} purities of ~88%. • The energy requirements for cycles using steam desorption are dominated by needs for thermal input, which results in lower costs than energy input in the form of electricity. Cyclic processes with operational costs of less than $100 tCO{sub 2}-net were described, and these results point to process and

  3. Low Cost, High Capacity Regenerable Sorbent for Carbon Dioxide Capture from Existing Coal-fired Power Plants

    SciTech Connect

    Alptekin, Gokhan; Jayaraman, Ambalavanan; Dietz, Steven

    2016-03-03

    In this project TDA Research, Inc (TDA) has developed a new post combustion carbon capture technology based on a vacuum swing adsorption system that uses a steam purge and demonstrated its technical feasibility and economic viability in laboratory-scale tests and tests in actual coal derived flue gas. TDA uses an advanced physical adsorbent to selectively remove CO2 from the flue gas. The sorbent exhibits a much higher affinity for CO2 than N2, H2O or O2, enabling effective CO2 separation from the flue gas. We also carried out a detailed process design and analysis of the new system as part of both sub-critical and super-critical pulverized coal fired power plants. The new technology uses a low cost, high capacity adsorbent that selectively removes CO2 in the presence of moisture at the flue gas temperature without a need for significant cooling of the flue gas or moisture removal. The sorbent is based on a TDA proprietary mesoporous carbon that consists of surface functionalized groups that remove CO2 via physical adsorption. The high surface area and favorable porosity of the sorbent also provides a unique platform to introduce additional functionality, such as active groups to remove trace metals (e.g., Hg, As). In collaboration with the Advanced Power and Energy Program of the University of California, Irvine (UCI), TDA developed system simulation models using Aspen PlusTM simulation software to assess the economic viability of TDA’s VSA-based post-combustion carbon capture technology. The levelized cost of electricity including the TS&M costs for CO2 is calculated as $116.71/MWh and $113.76/MWh for TDA system integrated with sub-critical and super-critical pulverized coal fired power plants; much lower than the $153.03/MWhand $147.44/MWh calculated for the corresponding amine based systems. The cost of CO2 captured for TDA’s VSA based system is $38

  4. Nanosilica-supported polyethoxyamines as low-cost, reversible carbon dioxide sorbents.

    PubMed

    Al-Azzawi, Omar M; Hofmann, Carrie M; Baker, Gary A; Baker, Sheila N

    2012-11-01

    Novel hybrid quasi-solid-state sorbents pairing inexpensive CO(2)-reactive polyethoxyamine (Jeffamine®) fluids with an abundantly available silica support have been investigated for carbon capture. The highest performance sorbent was capable of reversibly capturing close to 70 mg of CO(2) per gram of sorbent at 45°C, could be almost fully (~90%) regenerated by simple vacuum swing, and was stable over many sequential capture-release cycles. The new supports can be handled as solventless, free-flowing powders even post-CO(2) capture, obviating the mass flow problems arising from viscous liquid (or solid, gel, or wax) formation frequently attending carbamate formation. Our results have important ramifications for reducing the high costs of thermal regeneration in conventional carbon capture schemes, particularly in comparison with the aqueous monoethanolamine-based system currently favoured industrially. The strategy of uniformly dispersing a functional fluid onto a solid nanosupport in a manner that allows intimate contact with and diffusion of external gaseous species is additionally projected to find value in a range of gas separation and sensing endeavours.

  5. A calcium oxide sorbent process for bulk separation of carbon dioxide

    SciTech Connect

    Silaban, A.; Narcida, M.; Harrison, D.P.

    1992-02-01

    The expected commercialization of coal gasification technology in the US and world-wide will create a need for advanced gas purification and separation processes capable of operating at higher temperatures and in more hostile environments than is common today. For example, a high-temperature, high-pressure process capable of separating CO{sub 2} from coal-derived gas may find application in purifying synthesis gas for H{sub 2}, NH{sub 3}, or CH{sub 3}OH production. High temperature CO{sub 2} removal has the potential for significantly improving the operating efficiency of integrated gasification-molten carbonate fuel cells for electric power generation. This study proved the technical feasibility of a CO{sub 2}-separation process based upon the regenerable noncatalytic gas-solid reaction between CaO and CO{sub 2} to form CACO{sub 3}. Such a process operating at 650{degree}C and 15 atm with 15% CO{sub 2} in the coal gas has the potential for removing in excess of 99% of the CO{sub 2} fed. Selection of a sorbent precursor which, upon calcination, produces high-porosity CaO is important for achieving rapid and complete reaction. The addition of magnesium to the sorbent appears to improve the multicycle durability at a cost of reduced CO{sub 2} capacity per unit mass of sorbent. Reaction conditions, principally calcination and carbonation temperatures, are important factors in multicycle durability. Reaction pressure and CO{sub 2} concentration are important in so far as the initial rapid reaction rate is concerned, but are relatively unimportant in terms of sorbent capacity and durability. Indirect evidence for the simultaneous occurrence of the shift reaction and CO{sub 2}-removal reaction creates the possibility of a direct one-step process for the production of hydrogen from coal-derived gas.

  6. Multi-phase CFD modeling of solid sorbent carbon capture system

    SciTech Connect

    Ryan, E. M.; DeCroix, D.; Breault, Ronald W.; Xu, W.; Huckaby, E. David

    2013-01-01

    Computational fluid dynamics (CFD) simulations are used to investigate a low temperature post-combustion carbon capture reactor. The CFD models are based on a small scale solid sorbent carbon capture reactor design from ADA-ES and Southern Company. The reactor is a fluidized bed design based on a silica-supported amine sorbent. CFD models using both Eulerian–Eulerian and Eulerian–Lagrangian multi-phase modeling methods are developed to investigate the hydrodynamics and adsorption of carbon dioxide in the reactor. Models developed in both FLUENT® and BARRACUDA are presented to explore the strengths and weaknesses of state of the art CFD codes for modeling multi-phase carbon capture reactors. The results of the simulations show that the FLUENT® Eulerian–Lagrangian simulations (DDPM) are unstable for the given reactor design; while the BARRACUDA Eulerian–Lagrangian model is able to simulate the system given appropriate simplifying assumptions. FLUENT® Eulerian–Eulerian simulations also provide a stable solution for the carbon capture reactor given the appropriate simplifying assumptions.

  7. Multi-Phase CFD Modeling of Solid Sorbent Carbon Capture System

    SciTech Connect

    Ryan, Emily M.; DeCroix, David; Breault, Ronald W.; Xu, Wei; Huckaby, E. D.; Saha, Kringan; Darteville, Sebastien; Sun, Xin

    2013-07-30

    Computational fluid dynamics (CFD) simulations are used to investigate a low temperature post-combustion carbon capture reactor. The CFD models are based on a small scale solid sorbent carbon capture reactor design from ADA-ES and Southern Company. The reactor is a fluidized bed design based on a silica-supported amine sorbent. CFD models using both Eulerian-Eulerian and Eulerian-Lagrangian multi-phase modeling methods are developed to investigate the hydrodynamics and adsorption of carbon dioxide in the reactor. Models developed in both FLUENT® and BARRACUDA are presented to explore the strengths and weaknesses of state of the art CFD codes for modeling multi-phase carbon capture reactors. The results of the simulations show that the FLUENT® Eulerian-Lagrangian simulations (DDPM) are unstable for the given reactor design; while the BARRACUDA Eulerian-Lagrangian model is able to simulate the system given appropriate simplifying assumptions. FLUENT® Eulerian-Eulerian simulations also provide a stable solution for the carbon capture reactor given the appropriate simplifying assumptions.

  8. Development of a sorbent-based technology for control of mercury in flue gas

    SciTech Connect

    Wu, Jiann M.; Huang, Hann S.; Livengood, C.D.

    1996-03-01

    This paper presents results of research being, conducted at Argonne National Laboratory on the capture of elemental mercury in simulated flue gases by using dry sorbents. Experimental results from investigation of various sorbents and chemical additives for mercury control are reported. Of the sorbents investigated thus far, an activited-carbon-based sorbent impregnated with about 15% (by weight) of sulfur compound provided the best results. The key parameters affecting mercury control efficiency in a fixed-bed reactor, such as reactor loading, reactor temperature, sorbent size distribution, etc., were also studied, and the results ire presented. In addition to activated-carbon-based sorbents, a non-carbon-based sorbent that uses an inactive substrate treated with active chemicals is being developed. Preliminary, experimental results for mercury removal by this newly developed sorbent are presented.

  9. Development of Novel Carbon Sorbents for CO{sub 2} Capture

    SciTech Connect

    Krishnan, Gopala; Hornbostel, Marc; Bao, Jianer; Perez, Jordi; Nagar, Anoop; Sanjurjo, Angel

    2013-11-30

    An innovative, low-cost, and low-energy-consuming carbon dioxide (CO{sub 2}) capture technology was developed, based on CO{sub 2}adsorption on a high-capacity and durable carbon sorbent. This report describes the (1) performance of the concept on a bench-scale system; (2) results of parametric tests to determine the optimum operating conditions; (3) results of the testing with a flue gas from coal-fired boilers; and (4) evaluation of the technical and economic viability of the technology. The process uses a falling bed of carbon sorbent microbeads to separate the flue gas into two streams: a CO{sub 2} -lean flue gas stream from which > 90% of the CP{sub 2} is removed and a pure stream of CO{sub 2} that is ready for compression and sequestration. The carbo sorbent microbeads have several unique properties such as high CO{sub 2} capacity, low heat of adsorption and desorption (25 to 28 kJ/mole), mechanically robust, and rapid adsorption and desorption rates. The capture of CO{sub 2} from the flue gas is performed at near ambient temperatures in whic the sorbent microbeads flow down by gravity counter-current with the up-flow of the flue gas. The adsorbed CO{sub 2} is stripped by heating the CO{sub 2}-loaded sorbent to - 100°C, in contact with low-pressure (- 5 psig) steam in a section at the bottom of the adsorber. The regenerated sorben is dehydrated of adsorbed moisture, cooled, and lifted back to the adsorber. The CO{sub 2} from the desorber is essentially pure and can be dehydrated, compressed, and transported to a sequestration site. Bench-scale tests using a simulated flue gas showed that the integrated system can be operated to provide > 90% CO{sub 2} capture from a 15% CO{sub 2} stream in the adsorber and produce > 98% CO{sub 2} at the outlet of the stripper. Long-term tests ( 1,000 cycles) showed that the system can be operated reliably without sorbent agglomeration or attrition. The bench-scale reactor was also operated using a flue gas stream from a coal

  10. Pilot-Scale Evaluation of an Advanced Carbon Sorbent-Based Process for Post-Combustion Carbon Capture

    SciTech Connect

    Hornbostel, Marc

    2016-09-01

    The overall objective of this project is to achieve the DOE’s goal to develop advanced CO2 capture and separation technologies that can realize at least 90% CO2 removal from flue gas steams produced at a pulverized coal (PC) power plant at a cost of less than $40/tonne of CO2 captured. The principal objective is to test a CO2 capture process that will reduce the parasitic plant load by using a CO2 capture sorbent that will require a reduced amount of steam. The process is based on advanced carbon sorbents having a low heat of adsorption, high CO2 adsorption capacity, and excellent selectivity. While the intent of this project was to produce design and performance data by testing the sorbent using a slipstream of coal-derived flue gas at the National Carbon Capture Center (NCCC) under realistic conditions and continuous long-term operation, the project was terminated following completion of the detailing pilot plant design/engineering work on June 30, 2016.

  11. EVALUATION OF CARBON DIOXIDE CAPTURE FROM EXISTING COAL FIRED PLANTS BY HYBRID SORPTION USING SOLID SORBENTS

    SciTech Connect

    Benson, Steven; Browers, Bruce; Srinivasachar, Srivats; Laudal, Daniel

    2014-12-31

    Under contract DE-FE0007603, the University of North Dakota conducted the project Evaluation of Carbon Dioxide Capture from Existing Coal Fired Plants by Hybrid Sorption Using Solid Sorbents. As an important element of this effort, a Technical and Economic Feasibility Study was conducted by Barr Engineering Co. (Barr) in association with the University of North Dakota. The assessment developed a process flow diagram, major equipment list, heat balances for the SCPC power plant, capital cost estimate, operating cost estimate, levelized cost of electricity, cost of CO2 capture ($/ton) and three sensitivity cases for the CACHYS™ process.

  12. Novel sorbents for environmental remediation

    NASA Astrophysics Data System (ADS)

    Manariotis, Ioannis D.; Karapanagioti, Hrissi K.; Werner, David

    2014-05-01

    Nowadays, one of the major environmental problems is the pollution of aquatic systems and soil by persistent pollutants. Persistent pollutants have been found widespread in sediments, surface waters, and drinking water supplies. The removal of pollutants can be accomplished prior to their discharge to receiving bodies or by immobilizing them onto soil. Sorption is the most commonly applied process, and activated carbons have been widely used. Rapid progress in nanotechnology and a new focus on biomass-based instead of non-renewable starting materials have produced a wide range of novel engineered sorbents including biosorbents, biochars, carbon-based nanoparticles, bio-nano hybrid materials, and iron-impregnated activated carbons. Sorbent materials have been used in environmental remediation processes and especially in agricultural soil, sediments and contaminated soil, water treatment, and industrial wastewater treatment. Furthermore, sorbents may enhance the synergistic action of other processes, such as volatilization and biodegradation. Novel sorbents have been employed for the removal or immobilization of persistent pollutants such as and include heavy metals (As, Cr, Cu, Pb, Cd, and Hg), halogenated organic compounds, endocrine disrupting chemicals, metalloids and non-metallic elements, and other organic pollutants. The development and evaluation of novel sorbents requires a multidisciplinary approach encompassing environmental, nanotechnology, physical, analytical, and surface chemistry. The necessary evaluations encompass not only the efficiency of these materials to remove pollutants from surface waters and groundwater, industrial wastewater, polluted soils and sediments, etc., but also the potential side-effects of their environmental applications. The aim of this work is to present the results of the use of biochar and impregnated carbon sorbents for the removal of organic pollutants and metals. Furthermore, the new findings from the forthcoming session

  13. Single-Walled Carbon Nanotubes (SWCNTs), as a Novel Sorbent for Determination of Mercury in Air

    PubMed Central

    Golbabaei, Farideh; Ebrahimi, Ali; Shirkhanloo, Hamid; Koohpaei, Alireza; Faghihi-Zarandi, Ali

    2016-01-01

    Background: Based on the noticeable toxicity and numerous application of mercury in industries, removal of mercury vapor through sorbent is an important environmental challenge. Purpose of the Study: Due to their highly porous and hollow structure, large specific surface area, light mass density and strong interaction, Single-Walled Carbon Nanotubes (SWCNTs) sorbent were selected for this investigation. Methods: In this study, instrumental conditions, method procedure and different effective parameters such as adsorption efficiency, desorption capacity, time, temperature and repeatability as well as retention time of adsorbed mercury were studied and optimized. Also, mercury vapor was determined by cold vapor atomic absorption spectrometry (CV-AAS). Obtained data were analyzed by Independent T- test, Multivariate linear regression and one way–ANOVA finally. Results: For 80 mg nanotubes, working range of SWCNT were achieved 0.02-0.7 μg with linear range (R2=0.994). Our data revealed that maximum absorption capacity was 0.5 μg g-1 as well as limit of detection (LOD) for studied sorbent was 0.006 μg. Also, optimum time and temperature were reported, 10 min and 250 °C respectively. Retention time of mercury on CNTs for three weeks was over 90%. Results of repeated trials indicated that the CNTs had long life, so that after 30 cycles of experiments, efficiency was determined without performance loss. Conclusion: Results showed that carbon nanotubes have high potential for efficient extraction of mercury from air and can be used for occupational and environmental purposes. The study of adsorption properties of CNTs is recommended. PMID:26925918

  14. Characterization and preliminary assessment of a sorbent produced by accelerated mineral carbonation.

    PubMed

    Shtepenko, Olga L; Hills, Colin D; Coleman, Nichola J; Brough, Adrian

    2005-01-01

    This study shows that calcium silicate/aluminate-based materials can be carbonated to produce sorbents for metal removal. The material chosen for investigation, cement clinker, was accelerated carbonated, and its structural properties were investigated using X-ray diffraction (XRD), scanning electron microscopy, thermal gravimetric and differential thermal analysis, nuclear magnetic resonance spectroscopy, and nitrogen gas adsorption techniques. The principal carbonation reactions involved the transformation of dicalcium silicate, tricalcium silicate, and tricalcium aluminate into a Ca/Al-modified amorphous silica and calcium carbonate. It was found that carbonated cement had high acid buffering capacity, and maintained its structural integrity within a wide pH range. The uptake of Pb(II), Cd(II), Zn(II), Ni(II), Cr(II), Sr(II), Mo(VI), Cs(II), Co(II), and Cu(II) from concentrated (1000 mg L(-1)) single-metal solutions varied from 35 to 170 mg g(-1) of the carbonate cement. The removal of metals was hardly effected by the initial solution pH due to the buffering capability of the carbonated material. The kinetics of Pb, Cd, Cr, Sr, Cs, and Co removal followed a pseudo-second-order kinetic model, whereas the equilibrium batch data for Cu fitted the pseudo-first-order rate equation. PHREEQC simulation supported by XRD analysis suggested the formation of metal carbonates and silicates, calcium molybdate, and chromium (hydro)oxide. Cesium was likely to be adsorbed by Ca/Al-modified amorphous silica.

  15. The chromatography of poly(phenylene ether) on a porous graphitic carbon sorbent.

    PubMed

    Moyses, Stephan; Ginzburg, Anton

    2016-10-14

    A Porous Graphitic Carbon (PGC) column was evaluated for the analysis of poly(phenylene ether) (PPE). This column appears particularly well-suited for the separation of this polymer. Conditions for the elution of PPE either in adsorption mode with chloroform or size exclusion with 1,2,4-trichlorobenzene (TCB) as eluent were established. Elution of homologous species is obtained in chloroform that follows Martin's rule. A separation based on a gradient consisting of a sequence of non-solvent (acetonitrile), solvent/adsorli (chloroform) provided the highest peak capacity. In TCB, it is possible to obtain rapid size-based separation: with a flow rate of 0.7ml/min, the run time is less than two minutes for a series of polystyrene standards. The PGC column performs remarkably well in this mode and may be a viable solution when a short analysis time is critical such as in a combinatorial laboratory or in a two-dimensional chromatograph. In addition to its value as a sorbent for polymer separation, this column also deserves the attention of the materials engineer. Indeed, the PGC sorbent can be used as a model to probe the interaction between polymers and graphitic fillers such as carbon nanotubes or graphite nanosheets.

  16. Application of the sol-gel technique to develop synthetic calcium-based sorbents with excellent carbon dioxide capture characteristics.

    PubMed

    Broda, Marcin; Kierzkowska, Agnieszka M; Müller, Christoph R

    2012-02-13

    An option for reducing the release of greenhouse gases into the atmosphere is the implementation of CO(2) capture and storage (CCS) technologies. However, the costs associated with capturing CO(2) by using the currently available technology of amine scrubbing are very high. An emerging second-generation CO(2) capture technology is the use of calcium-based sorbents, which exploit the carbonation and calcination reactions of CaO, namely, CaO+CO(2) ↔CaCO(3). Naturally occurring Ca-based sorbents are inexpensive, but show a very rapid decay of CO(2) uptake capacity with cycle number. Here, we report the development of synthetic Ca-based CO(2) sorbents using a sol-gel technique. Using this technique, we are able to synthesize a nanostructured material that possesses a high surface area and pore volume and shows excellent CO(2) capture characteristics over many cycles. Furthermore, we are able to establish a clear relationship between the structure of the sorbent and its performance. After 30 cycles of calcination and carbonation, the best material possessed a CO(2) uptake capacity of 0.51 g of CO(2) per gram of sorbent; a value that is about 250 % higher than that for naturally occurring Havelock limestone.

  17. Equilibrium and Absorption Kinetics of Carbon Dioxide by solid Supported Amine Sorbent

    SciTech Connect

    Monazam, Esmail R.; Shadle, Lawrence J.; Siriwardane, Ranjani

    2011-11-01

    The equilibrium and conversion-time data on the absorption of carbon dioxide (CO{sub 2}) with amine-based solid sorbent were analyzed over the range of 303–373 K. Data on CO{sub 2} loading on amine based solid sorbent at these temperatures and CO{sub 2} partial pressure between 10 and 760 mm Hg obtained from volumetric adsorption apparatus were fitted to a simple equilibrium model to generate the different parameters (including equilibrium constant) in the model. Using these constants, a correlation was obtained to define equilibrium constant and maximum CO{sub 2} loading as a function of temperature. In this study, a shrinking core model (SCM) was applied to elucidate the relative importance of pore diffusion and surface chemical reaction in controlling the rate of reaction. Application of SCM to the data suggested a surface reaction-controlled mechanism for the temperature of up to 40°C and pore-diffusion mechanism at higher temperature.

  18. Solid sorbents for removal of carbon dioxide from gas streams at low temperatures

    DOEpatents

    Sirwardane, Ranjani V.

    2005-06-21

    New low-cost CO.sub.2 sorbents are provided that can be used in large-scale gas-solid processes. A new method is provided for making these sorbents that involves treating substrates with an amine and/or an ether so that the amine and/or ether comprise at least 50 wt. percent of the sorbent. The sorbent acts by capturing compounds contained in gaseous fluids via chemisorption and/or physisorption between the unit layers of the substrate's lattice where the polar amine liquids and solids and/or polar ether liquids and solids are located. The method eliminates the need for high surface area supports and polymeric materials for the preparation of CO.sub.2 capture systems, and provides sorbents with absorption capabilities that are independent of the sorbents' surface areas. The sorbents can be regenerated by heating at temperatures in excess of 35.degree. C.

  19. Solid Sorbents for Removal of Carbon Dioxide from Gas Streams at Low Temperatures

    SciTech Connect

    Sirwardane, Ranjani V.

    2005-06-21

    New low-cost CO2 sorbents are provided that can be used in large-scale gas-solid processes. A new method is provided for making these sorbents that involves treating substrates with an amine and/or an ether so that the amine and/or ether comprise at least 50 wt. percent of the sorbent. The sorbent acts by capturing compounds contained in gaseous fluids via chemisorption and/or physisorption between the unit layers of the substrate's lattice where the polar amine liquids and solids and/or polar ether liquids and solids are located. The method eliminates the need for high surface area supports and polymeric materials for the preparation of CO2 capture systems, and provides sorbents with absorption capabilities that are independent of the sorbents' surface areas. The sorbents can be regenerated by heating at temperatures in excess of 35 degrees C.

  20. EVALUATION OF CARBON DIOXIDE CAPTURE FROM EXISTING COAL FIRED PLANTS BY HYBRID SORPTION USING SOLID SORBENTS

    SciTech Connect

    Benson, Steven; Palo, Daniel; Srinivasachar, Srivats; Laudal, Daniel

    2014-12-01

    Under contract DE-FE0007603, the University of North Dakota conducted the project Evaluation of Carbon Dioxide Capture from Existing Coal Fired Plants by Hybrid Sorption Using Solid Sorbents. As an important element of this effort, an Environmental Health and Safety (EH&S) Assessment was conducted by Barr Engineering Co. (Barr) in association with the University of North Dakota. The assessment addressed air and particulate emissions as well as solid and liquid waste streams. The magnitude of the emissions and waste streams was estimated for evaluation purposes. EH&S characteristics of materials used in the system are also described. This document contains data based on the mass balances from both the 40 kJ/mol CO2 and 80 kJ/mol CO2 desorption energy cases evaluated in the Final Technical and Economic Feasibility study also conducted by Barr Engineering.

  1. ELEMENTAL MERCURY CAPTURE BY ACTIVATED CARBON IN A FLOW REACTOR

    EPA Science Inventory


    The paper gives results of bench-scale experiments in a flow reactor to simulate the entrained-flow capture of elemental mercury (Hgo) using solid sorbents. Adsorption of Hgo by a lignite-based activated carbon (Calgon FGD) was examined at different carbon/mercury (C/Hg) rat...

  2. Desulfurization sorbent regeneration

    DOEpatents

    Jalan, V.M.; Frost, D.G.

    1982-07-07

    A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500/sup 0/C to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent. This method may be used for high-temperature fuel cells.

  3. Utility flue gas mercury control via sorbent injection

    SciTech Connect

    Chang, R.; Carey, T.; Hargrove, B.

    1996-12-31

    The potential for power plant mercury control under Title III of the 1990 Clean Air Act Amendments generated significant interest in assessing whether cost effective technologies are available for removing the mercury present in fossil-fired power plant flue gas. One promising approach is the direct injection of mercury sorbents such as activated carbon into flue gas. This approach has been shown to be effective for mercury control from municipal waste incinerators. However, tests conducted to date on utility fossil-fired boilers show that it is much more difficult to remove the trace species of mercury present in flue gas. EPRI is conducting research in sorbent mercury control including bench-scale evaluation of mercury sorbent activity and capacity with simulated flue gas, pilot testing under actual flue gas conditions, evaluation of sorbent regeneration and recycle options, and the development of novel sorbents. A theoretical model that predicts maximum mercury removals achievable with sorbent injection under different operating conditions is also being developed. This paper presents initial bench-scale and model results. The results to date show that very fine and large amounts of sorbents are needed for mercury control unless long residence times are available for sorbent-mercury contact. Also, sorbent activity and capacity are highly dependent on flue gas composition, temperature, mercury species, and sorbent properties. 10 refs., 4 figs., 2 tabs.

  4. Preliminary carbon dioxide capture technical and economic feasibility study evaluation of carbon dioxide capture from existing fired plants by hybrid sorption using solid sorbents

    SciTech Connect

    Benson, Steven; Envergex, Srivats; Browers, Bruce; Thumbi, Charles

    2013-01-01

    Barr Engineering Co. was retained by the Institute for Energy Studies (IES) at University of North Dakota (UND) to conduct a technical and economic feasibility analysis of an innovative hybrid sorbent technology (CACHYS™) for carbon dioxide (CO2) capture and separation from coal combustion–derived flue gas. The project team for this effort consists of the University of North Dakota, Envergex LLC, Barr Engineering Co., and Solex Thermal Science, along with industrial support from Allete, BNI Coal, SaskPower, and the North Dakota Lignite Energy Council. An initial economic and feasibility study of the CACHYS™ concept, including definition of the process, development of process flow diagrams (PFDs), material and energy balances, equipment selection, sizing and costing, and estimation of overall capital and operating costs, is performed by Barr with information provided by UND and Envergex. The technology—Capture from Existing Coal-Fired Plants by Hybrid Sorption Using Solid Sorbents Capture (CACHYS™)—is a novel solid sorbent technology based on the following ideas: reduction of energy for sorbent regeneration, utilization of novel process chemistry, contactor conditions that minimize sorbent-CO2 heat of reaction and promote fast CO2 capture, and a low-cost method of heat management. The technology’s other key component is the use of a low-cost sorbent.

  5. Mercury adsorption on a carbon sorbent derived from fruit shell of Terminalia catappa.

    PubMed

    Inbaraj, B Stephen; Sulochana, N

    2006-05-20

    A carbonaceous sorbent derived from the fruit shell of Indian almond (Terminalia catappa) by sulfuric acid treatment was used for the removal of mercury(II) from aqueous solution. Sorption of mercury depends on the pH of the aqueous solution with maximum uptake occurring in the pH range of 5-6. The kinetics of sorption conformed well to modified second order model among the other kinetic models (pseudo first order and pseudo second order) tested. The Langmuir and Redlich-Peterson isotherm models defined the equilibrium data precisely compared to Freundlich model and the monolayer sorption capacity obtained was 94.43 mg/g. Sorption capacity increased with increase in temperature and the thermodynamic parameters, DeltaH degrees , DeltaS degrees and DeltaG degrees , indicated the Hg(II) sorption to be endothermic and spontaneous with increased randomness at the solid-solution interface. An optimum carbon dose of 4 g/l was required for the maximum uptake of Hg(II) from 30 mg/l and the mathematical relationship developed showed a correlation of 0.94 between experimental and calculated percentage removals for any carbon dose studied. About 60% of Hg(II) adsorbed was recovered from the spent carbon at pH 1.0, while 94% of it was desorbed using 1.0% KI solution.

  6. Regenerable solid imine sorbents

    DOEpatents

    Gray, McMahan; Champagne, Kenneth J.; Fauth, Daniel; Beckman, Eric

    2013-09-10

    Two new classes of amine-based sorbents are disclosed. The first class comprises new polymer-immobilized tertiary amine sorbents; the second class new polymer-bound amine sorbents. Both classes are tailored to facilitate removal of acid anhydrides, especially carbon dioxide (CO.sub.2), from effluent gases. The amines adsorb acid anhydrides in a 1:1 molar ratio. Both classes of amine sorbents adsorb in the temperature range from about 20.degree. C. upwards to 90.degree. C. and can be regenerated by heating upwards to 100.degree. C.

  7. Estimates of increased black carbon emissions from electrostatic precipitators during powdered activated carbon injection for mercury emissions control.

    PubMed

    Clack, Herek L

    2012-07-03

    The behavior of mercury sorbents within electrostatic precipitators (ESPs) is not well-understood, despite a decade or more of full-scale testing. Recent laboratory results suggest that powdered activated carbon exhibits somewhat different collection behavior than fly ash in an ESP and particulate filters located at the outlet of ESPs have shown evidence of powdered activated carbon penetration during full-scale tests of sorbent injection for mercury emissions control. The present analysis considers a range of assumed differential ESP collection efficiencies for powdered activated carbon as compared to fly ash. Estimated emission rates of submicrometer powdered activated carbon are compared to estimated emission rates of particulate carbon on submicrometer fly ash, each corresponding to its respective collection efficiency. To the extent that any emitted powdered activated carbon exhibits size and optical characteristics similar to black carbon, such emissions could effectively constitute an increase in black carbon emissions from coal-based stationary power generation. The results reveal that even for the low injection rates associated with chemically impregnated carbons, submicrometer particulate carbon emissions can easily double if the submicrometer fraction of the native fly ash has a low carbon content. Increasing sorbent injection rates, larger collection efficiency differentials as compared to fly ash, and decreasing sorbent particle size all lead to increases in the estimated submicrometer particulate carbon emissions.

  8. Design and Development of New Carbon-Based Sorbent Systems for an Effective Containment of Hydrogen

    SciTech Connect

    Alan C. Cooper

    2012-05-03

    This is a summary for work performed under cooperative agreement DE FC36 04GO14006 (Design and Development of New Carbon-based Sorbent Systems for an Effective Containment of Hydrogen). The project was directed to discover new solid and liquid materials that use reversible catalytic hydrogenation as the mechanism for hydrogen capture and storage. After a short period of investigation of solid materials, the inherent advantages of storing and transporting hydrogen using liquid-phase materials focused our attention exclusively on organic liquid hydrogen carriers (liquid carriers). While liquid carriers such as decalin and methylcyclohexane were known in the literature, these carriers suffer from practical disadvantages such as the need for very high temperatures to release hydrogen from the carriers and difficult separation of the carriers from the hydrogen. In this project, we were successful in using the prediction of reaction thermodynamics to discover liquid carriers that operate at temperatures up to 150 C lower than the previously known carriers. The means for modifying the thermodynamics of liquid carriers involved the use of certain molecular structures and incorporation of elements other than carbon into the carrier structure. The temperature decrease due to the more favorable reaction thermodynamics results in less energy input to release hydrogen from the carriers. For the first time, the catalytic reaction required to release hydrogen from the carriers could be conducted with the carrier remaining in the liquid phase. This has the beneficial effect of providing a simple means to separate the hydrogen from the carrier.

  9. Hierarchical calibration and validation of computational fluid dynamics models for solid sorbent-based carbon capture

    SciTech Connect

    Lai, Canhai; Xu, Zhijie; Pan, Wenxiao; Sun, Xin; Storlie, Curtis; Marcy, Peter; Dietiker, Jean-François; Li, Tingwen; Spenik, James

    2016-01-01

    To quantify the predictive confidence of a solid sorbent-based carbon capture design, a hierarchical validation methodology—consisting of basic unit problems with increasing physical complexity coupled with filtered model-based geometric upscaling has been developed and implemented. This paper describes the computational fluid dynamics (CFD) multi-phase reactive flow simulations and the associated data flows among different unit problems performed within the said hierarchical validation approach. The bench-top experiments used in this calibration and validation effort were carefully designed to follow the desired simple-to-complex unit problem hierarchy, with corresponding data acquisition to support model parameters calibrations at each unit problem level. A Bayesian calibration procedure is employed and the posterior model parameter distributions obtained at one unit-problem level are used as prior distributions for the same parameters in the next-tier simulations. Overall, the results have demonstrated that the multiphase reactive flow models within MFIX can be used to capture the bed pressure, temperature, CO2 capture capacity, and kinetics with quantitative accuracy. The CFD modeling methodology and associated uncertainty quantification techniques presented herein offer a solid framework for estimating the predictive confidence in the virtual scale up of a larger carbon capture device.

  10. Performance and Kinetics of a solid Amine Sorbent for Carbon Dioxide Removal

    SciTech Connect

    Monazam, Esmail R.; Shadle, Lawrence J.; Siriwardane, Ranjani

    2011-10-05

    The kinetics of the reaction between CO{sub 2} and amine/bentonite particle were estimated over the range of 303–363 K from adsorption data obtained by TGA. The weight percent of amine, reaction temperature, and particle diameter were considered as experimental variables. The sorbent maximum or equilibrium CO{sub 2} uptake was found to be linearly dependent on temperature; decreasing with increasing temperature when tested in a 100% CO{sub 2} environment. Reactivity data for amine/bentonite particle with CO{sub 2} were presented and discussed. On the basis of the isothermal TGA results, reaction order and the value of activation energy have been obtained. These kinetic parameters are similar to those reported for MEA and DEA in aqueous solutions. The kinetic model was used to predict the fractional conversion at different temperature exhibiting good agreement with experimental data.

  11. Soil washing enhancement with solid sorbents

    SciTech Connect

    El-Shoubary, Y.M.; Woodmansee, D.E.

    1996-12-31

    Soil washing is a dynamic, physical process that remediates contaminated soil through two mechanisms: particle size separation and transfer of the contaminant into the (mostly) liquid stream. The performance of different sorbents and additives to remove motor oil from sea sand was tested. Hydrocyclone, attrition scrubber, and froth flotation equipment were used for the decontamination study. Sorbents and additives were mixed with soils in the attrition scrubber prior to flotation. Sorbents used were granular activated carbon, powder activated carbon, and rubber tires. Chemical additives used were calcium hydroxide, sodium carbonate, Alconox{reg_sign}, Triton{reg_sign} X-100 and Triton{reg_sign} X-114. When a froth flotation run was performed using no additive, washed soils {open_quotes}tails{close_quotes} contained 4000 ppm of total oil and grease (TOG). However, when carbon or rubber (6% by weight) was added to the contaminated soils the washed soils {open_quotes}tails{close_quotes} contained 4000 ppm of total oil and grease (TOG). The addition of sodium carbonate or calcium hydroxide (6% by weight) had same effects as sorbents. In both cases washed soil {open_quotes}tails{close_quotes} contained total oil and grease of less than 1000 ppm. The use of these non-hazardous additives or sorbent can enhance the soil washing process and consequently saves on time (residence time in equipment design) required to achieve the target clean up levels. 18 refs., 12 figs.

  12. Porous covalent electron-rich organonitridic frameworks as highly selective sorbents for methane and carbon dioxide.

    PubMed

    Mohanty, Paritosh; Kull, Lilian D; Landskron, Kai

    2011-07-19

    Carbon dioxide capture from point sources like coal-fired power plants is considered to be a solution for stabilizing the CO(2) level in the atmosphere to avoid global warming. Methane is an important energy source that is often highly diluted by nitrogen in natural gas. For the separation of CO(2) and CH(4) from N(2) in flue gas and natural gas, respectively, sorbents with high and reversible gas uptake, high gas selectivity, good chemical and thermal stability, and low cost are desired. Here we report the synthesis and CO(2), CH(4), and N(2) adsorption properties of hierarchically porous electron-rich covalent organonitridic frameworks (PECONFs). These were prepared by simple condensation reactions between inexpensive, commercially available nitridic and electron-rich aromatic building units. The PECONF materials exhibit high and reversible CO(2) and CH(4) uptake and exceptional selectivities of these gases over N(2). The materials do not oxidize in air up to temperature of 400 °C.

  13. New SERS-active alumina-based sorbents containing Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Yurova, Nadezhda S.; Markina, Natalia E.; Galushka, Victor V.; Burashnikova, Marina M.; Zakharevich, Andrey M.; Markin, Alexey V.; Rusanova, Tatiana Y.

    2016-04-01

    New SERS-active materials were obtained by preparation of alumina with embedded silver nanoparticles and their application both as sorbents for pre-concentration and SERS platforms was studied. The influence of ionic strength on Ag NPs size, absorption spectra and SERS signal was investigated. Synthesized materials were examined by Raman spectroscopy, scanning electron microscopy, and UV-visible spectroscopy. The optimal conditions for SERSmeasurements were chosen. Synthesized materials were applied for pre-concentration of model analytes (Rhodamine 6G, folic acid and pyrene) and their SERS detection directly within the sorbent. It was shown that the recovery of analytes could be improved by alumina modification. The combination of surface-enhanced Raman spectroscopy with preconcentration is a promising instrument for analytical applications.

  14. Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas

    SciTech Connect

    Lee, S.H.D.; Swift, W.M.; Johnson, I.

    1980-01-01

    Diatomaceous earth and activated bauxite were tested as granular sorbents for use as filter media in granular-bed filters for the removal of gaseous alkali metal compounds from the hot (800/sup 0/C) flue gas of PFBC. Tests were performed at atmospheric pressure, using NaCl vapor transported in relatively dry simulated flue gas of PFBC. Either a fixed-bed combustor or a high-temperature sorption test rig was used. The effects of sorbent bed temperature, superficial gas velocity, gas hourly space velocity, and NaCl-vapor concentration in flue gas on the sorption behavior of these two sorbents and their ultimate sorption capacities were determined. Both diatomaceous earth and activated bauxite were found to be very effective in removing NaCl vapor from flue gas. Preliminary cost evaluations showed that they are economically attractive as granular sorbents for cleaning alkali vapor from simulated flue gas.

  15. Sorbents with high efficiency for CO2 capture based on amines-supported carbon for biogas upgrading.

    PubMed

    Pino, Lidia; Italiano, Cristina; Vita, Antonio; Fabiano, Concetto; Recupero, Vincenzo

    2016-10-01

    Sorbents for CO2 capture have been prepared by wet impregnation of a commercial active carbon (Ketjen-black, Akzo Nobel) with two CO2-philic compounds, polyethylenimine (PEI) and tetraethylenepentamine (TEPA), respectively. The effects of amine amount (from 10 to 70wt.%), CO2 concentration in the feed, sorption temperature and gas hourly space velocity on the CO2 capture performance have been investigated. The sorption capacity has been evaluated using the breakthrough method, with a fixed bed reactor equipped with on line gas chromatograph. The samples have been characterized by N2 adsorption-desorption, scanning electron microscopy and energy dispersive X-ray (SEM/EDX). A promising CO2 sorption capacity of 6.90 mmol/gsorbent has been obtained with 70wt.% of supported TEPA at 70°C under a stream containing 80vol% of CO2. Sorption tests, carried out with simulated biogas compositions (CH4/CO2 mixtures), have revealed an appreciable CO2 separation selectivity; stable performance was maintained for 20 adsorption-desorption cycles.

  16. Evaluation of the sediment remediation potential of magnetite impregnated activated carbons and biochars

    NASA Astrophysics Data System (ADS)

    Werner, David; Han, Zhantao; Karapanagioti, Hrissi

    2014-05-01

    We evaluated the sediment remediation potential of magnetic composite materials synthesized by precipitating magnetite minerals onto activated carbons and biochars. Magnetite impregnation did not reduce the phenanthrene sorption capacity of the activated carbon or biochar component of the composite materials. The phenanthrene sorption capacity of the composite materials correlated with the surface areas of the pristine carbonaceous sorbents. XRD data and mass magnetic susceptibility data indicate that the mineral component of the composites is indeed nearly 100% magnetite. Addition of magnetic activated carbon to River Tyne sediment slurries reduced polycyclic aromatic hydrocarbon availability by more than 90%. After 3 months of mixing, 77% of the added magnetic activated carbon could be recovered with a magnetic rod. Continued monitoring showed that polycyclic aromatic hydrocarbon availability remained low following the magnetic recovery of most of the added sorbent mass. XRD analysis confirmed the presence of magnetite in the recovered sorbent material, with some other mineral phases such as calcite and quartz also being identifiable. Magnetic activated carbon has potential as a recoverable sorbent amendment for the treatment of sediment polluted with hydrophobic organic compounds. Further work will include an evaluation of the long-term magnetic sorbent effectiveness and stability in unmixed sediments under aerobic and anaerobic conditions and regeneration and re-use options for the recovered sorbent materials.

  17. A calcium oxide sorbent process for bulk separation of carbon dioxide. Quarterly progress report, October--December 1991

    SciTech Connect

    Silaban, A.; Narcida, M.; Harrison, D.P.

    1992-02-01

    The expected commercialization of coal gasification technology in the US and world-wide will create a need for advanced gas purification and separation processes capable of operating at higher temperatures and in more hostile environments than is common today. For example, a high-temperature, high-pressure process capable of separating CO{sub 2} from coal-derived gas may find application in purifying synthesis gas for H{sub 2}, NH{sub 3}, or CH{sub 3}OH production. High temperature CO{sub 2} removal has the potential for significantly improving the operating efficiency of integrated gasification-molten carbonate fuel cells for electric power generation. This study proved the technical feasibility of a CO{sub 2}-separation process based upon the regenerable noncatalytic gas-solid reaction between CaO and CO{sub 2} to form CACO{sub 3}. Such a process operating at 650{degree}C and 15 atm with 15% CO{sub 2} in the coal gas has the potential for removing in excess of 99% of the CO{sub 2} fed. Selection of a sorbent precursor which, upon calcination, produces high-porosity CaO is important for achieving rapid and complete reaction. The addition of magnesium to the sorbent appears to improve the multicycle durability at a cost of reduced CO{sub 2} capacity per unit mass of sorbent. Reaction conditions, principally calcination and carbonation temperatures, are important factors in multicycle durability. Reaction pressure and CO{sub 2} concentration are important in so far as the initial rapid reaction rate is concerned, but are relatively unimportant in terms of sorbent capacity and durability. Indirect evidence for the simultaneous occurrence of the shift reaction and CO{sub 2}-removal reaction creates the possibility of a direct one-step process for the production of hydrogen from coal-derived gas.

  18. Evaluation of Carbon Dioxide Capture From Existing Coal Fired Plants by Hybrid Sorption Using Solid Sorbents

    SciTech Connect

    Benson, Steven; Srinivasachar, Srivats; Laudal, Daniel; Browers, Bruce

    2014-12-31

    A novel hybrid solid sorbent technology for CO₂ capture and separation from coal combustion-derived flue gas was evaluated. The technology – Capture of CO₂ by Hybrid Sorption (CACHYS™) – is a solid sorbent technology based on the following ideas: 1) reduction of energy for sorbent regeneration, 2) utilization of novel process chemistry, 3) contactor conditions that minimize sorbent-CO₂ heat of reaction and promote fast CO₂ capture, and 4) low-cost method of heat management. This report provides key information developed during the course of the project that includes sorbent performance, energy for sorbent regeneration, physical properties of the sorbent, the integration of process components, sizing of equipment, and overall capital and operational cost of the integrated CACHYS™ system. Seven sorbent formulations were prepared and evaluated at the lab-scale for energy requirements and CO₂ capture performance. Sorbent heat of regeneration ranged from 30-80 kJ/mol CO₂ and was found to be dependent on process conditions. Two sorbent formulations (designated HCK-4 & HCK-7) were down-selected for additional fixed-bed testing. Additional testing involved subjecting the sorbents to 100 continuous cycles in the fixed-bed reactor to determine performance as a function of time. The working capacity achieved for HCK-4 sorbent ranged from 5.5-8.0 g CO₂/100 g sorbent, while the HCK-7 typically ranged from 8.0-10.0 g CO₂/100 g sorbent. Overall, there was no deterioration in capacity with continuous cycling for either sorbent. The CACHYS™ bench-scale testing system designed and fabricated under this award consists of a dual circulating fluidized-bed adsorber and a moving-bed regenerator. The system takes a flue gas slipstream from the University of North Dakota’s coal-fired steam plant. Prior to being sent to the adsorber, the flue gas is scrubbed to remove SO₂ and particulate. During parametric testing of the adsorber, CO₂ capture achieved using

  19. Activation and reactivity of novel calcium-based sorbents for dry SO2 control in boilers (journal article)

    SciTech Connect

    Jozewicz, W.; Kirchgessner, D.A.

    1989-01-01

    Chemically modified Ca(OH)2 sorbents for SO2 control in utility boilers were tested in an electrically heated, bench-scale isothermal flow reactor, operated at between 700 and 1000 C and residence times of from 0.6 to 2 sec calculated from bulk gas flowrates. Novel surfactant-modified Ca(OH)2 (SM-Ca(OH)2) sorbents were compared to conventional Ca(OH)2 produced by dry hydration (DH-Ca(OH)2). Sorbents were activated in the flow reactor. The gas composition was 5 vol % oxygen with the balance nitrogen. Activated sorbents, SM-CaO and DH-CaO, were size classified with an inertial cascade impactor downstream of the flow reactor. The structure of each separated fraction (six trays plus preimpactor, D50 from 0.74 to > 11.9 micrometers) was characterized by nitrogen adsorption. For each size fraction measured, the surface area was higher for SM-CaO than for DH-CaO. The effect of thermal sintering was the increase of median pore size as a result of eliminating fine pores (below 100 A). Changes in the pore structure of Ca(OH)2 sorbents reacting with SO2 were also investigated. The effect of thermal sintering on pore structure of sorbents reacting with SO2 was eliminated. The degree of conversion was controlled by varying gas-phase mass transfer resistance (SO2 concentrations from 50 to 3000 ppm).

  20. Zirconium-carbon hybrid sorbent for removal of fluoride from water: oxalic acid mediated Zr(IV) assembly and adsorption mechanism.

    PubMed

    Velazquez-Jimenez, Litza Halla; Hurt, Robert H; Matos, Juan; Rangel-Mendez, Jose Rene

    2014-01-21

    When activated carbon (AC) is modified with zirconium(IV) by impregnation or precipitation, the fluoride adsorption capacity is typically improved. There is significant potential to improve these hybrid sorbents by controlling the impregnation conditions, which determine the assembly and dispersion of the Zr phases on carbon surfaces. Here, commercial activated carbon was modified with Zr(IV) together with oxalic acid (OA) used to maximize the zirconium dispersion and enhance fluoride adsorption. Adsorption experiments were carried out at pH 7 and 25 °C with a fluoride concentration of 40 mg L(-1). The OA/Zr ratio was varied to determine the optimal conditions for subsequent fluoride adsorption. The data was analyzed using the Langmuir and Freundlich isotherm models. FTIR, XPS, and the surface charge distribution were performed to elucidate the adsorption mechanism. Potentiometric titrations showed that the modified activated carbon (ZrOx-AC) possesses positive charge at pH lower than 7, and FTIR analysis demonstrated that zirconium ions interact mainly with carboxylic groups on the activated carbon surfaces. Moreover, XPS analysis demonstrated that Zr(IV) interacts with oxalate ions, and the fluoride adsorption mechanism is likely to involve -OH(-) exchange from zirconyl oxalate complexes.

  1. Zirconium-carbon hybrid sorbent for removal of fluoride from water: oxalic acid mediated Zr(IV) assembly and adsorption mechanism

    PubMed Central

    Halla, Velazquez-Jimenez Litza; Hurt Robert, H; Juan, Matos; Rene, Rangel-Mendez Jose

    2014-01-01

    When activated carbon (AC) is modified with zirconium(IV) by impregnation or precipitation, the fluoride adsorption capacity is typically improved. There is significant potential to improve these hybrid sorbent by controlling the impregnation conditions, which determine the assembly and dispersion of the Zr phases on carbon surfaces. Here, commercial activated carbon was modified with Zr(IV) together with oxalic acid (OA) used to maximize the zirconium dispersion and enhance fluoride adsorption. Adsorption experiments were carried out at pH 7 and 25 °C with a fluoride concentration of 40 mg L−1. The OA/Zr ratio was varied to determine the optimal conditions for subsequent fluoride adsorption. The data was analyzed using the Langmuir and Freundlich isotherm models. FTIR, XPS and the surface charge distribution were performed to elucidate the adsorption mechanism. Potentiometric titrations showed that the modified activated carbon (ZrOx-AC) possesses positive charge at pH lower than 7, and FTIR analysis demonstrated that zirconium ions interact mainly with carboxylic groups on the activated carbon surfaces. Moreover, XPS analysis demonstrated that Zr(IV) interacts with oxalate ions, and the fluoride adsorption mechanism is likely to involve –OH− exchange from zirconyl oxalate complexes. PMID:24359079

  2. Operation of a breadboard liquid-sorbent/membrane-contactor system for removing carbon dioxide and water vapor from air

    NASA Technical Reports Server (NTRS)

    Mccray, Scott B.; Ray, Rod; Newbold, David D.; Millard, Douglas L.; Friesen, Dwayne T.; Foerg, Sandra

    1992-01-01

    Processes to remove and recover carbon dioxide (CO2) and water vapor from air are essential for successful long-duration space missions. This paper presents results of a developmental program focused on the use of a liquid-sorbent/membrane-contactor (LSMC) system for removal of CO2 and water vapor from air. In this system, air from the spacecraft cabin atmosphere is circulated through one side of a hollow-fiber membrane contactor. On the other side of the membrane contactor is flowed a liquid sorbent, which absorbs the CO2 and water vapor from the feed air. The liquid sorbent is then heated to desorb the CO2 and water vapor. The CO2 is subsequently removed from the system as a concentrated gas stream, whereas the water vapor is condensed, producing a water stream. A breadboard system based on this technology was designed and constructed. Tests showed that the LSMC breadboard system can produce a CO2 stream and a liquid-water stream. Details are presented on the operation of the system, as well as the effects on performance of variations in feed conditions.

  3. Study of CO2 sorbents for extravehicular activity

    NASA Technical Reports Server (NTRS)

    Colombo, G. V.

    1973-01-01

    Portable life support equipment was studied for meeting the requirements of extravehicular activities. Previous studies indicate that the most promising method for performing the CO2 removal function removal function were metallic oxides and/or metallic hydroxides. Mgo, Ag2, and Zno metallic oxides and Mg(OH)2 and Zn(OH)2 metallic hydroxides were studied, by measuring sorption and regeneration properties of each material. The hydroxides of Mg and Zn were not regenerable and the zinc oxide compounds showed no stable form. A silver oxide formulation was developed which rapidly absorbs approximately 95% of its 0.19 Kg CO2 Kg oxide and has shown no sorption or structural degeneration through 22 regenerations. It is recommended that the basic formula be further developed and tested in large-scale beds under simulated conditions.

  4. Long Duration Sorbent Testbed

    NASA Technical Reports Server (NTRS)

    Howard, David F.; Knox, James C.; Long, David A.; Miller, Lee; Cmaric, Gregory; Thomas, John

    2016-01-01

    The Long Duration Sorbent Testbed (LDST) is a flight experiment demonstration designed to expose current and future candidate carbon dioxide removal system sorbents to an actual crewed space cabin environment to assess and compare sorption working capacity degradation resulting from long term operation. An analysis of sorbent materials returned to Earth after approximately one year of operation in the International Space Station's (ISS) Carbon Dioxide Removal Assembly (CDRA) indicated as much as a 70% loss of working capacity of the silica gel desiccant material at the extreme system inlet location, with a gradient of capacity loss down the bed. The primary science objective is to assess the degradation of potential sorbents for exploration class missions and ISS upgrades when operated in a true crewed space cabin environment. A secondary objective is to compare degradation of flight test to a ground test unit with contaminant dosing to determine applicability of ground testing.

  5. Novel surface molecularly imprinted material modified multi-walled carbon nanotubes as solid-phase extraction sorbent for selective extraction gallium ion from fly ash.

    PubMed

    Zhang, Zhaohui; Zhang, Huabin; Hu, Yufang; Yang, Xiao; Yao, Shouzhuo

    2010-06-30

    A new gallium (Ga(III)) ion-imprinted multi-walled carbon nanotubes (CNTs) composite sorbent was synthesized by a surface imprinting technique. The Ga(III) ion-imprinted/multi-walled carbon nanotubes (Ga(III)-imprinted/CNTs) sorbent was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), nitrogen adsorption experiment, static adsorption experiment, and solid-phase extraction (SPE) experiment. The effects of sample volume, sample pH, washing and elution conditions on the extraction of Ga(III) ion from real sample were studied in detail. The imprinted sorbent offered a fast kinetics for the adsorption of Ga(III). The maximum static adsorption capacity of the imprinted sorbent towards was 58.8 micromol g(-1). The largest selectivity coefficient for Ga(III) in the presence of Al(III) was over 57.3. Compared with non-imprinted sorbent, the imprinted sorbent showed good imprinting effect for Ga(III) ion, the imprinting factor (alpha) was 2.6, the selectivity factor (beta) was 2.4 and 2.9 for Al(III) and Zn(II), respectively. The developed imprinted SPE method was applied successfully to the detection of trace Ga(III) ion in fly ash samples with satisfactory results.

  6. Investigation and demonstration of dry carbon-based sorbent injection for mercury control. Quarterly technical report, July 1, 1996--September 31, 1996

    SciTech Connect

    Hunt, T.; Sjostrom, S.; Smith, J.

    1996-11-06

    The overall objective of this two phase program is to investigate the use of dry carbon-based sorbents for mercury control. This information is important to the utility industry in anticipation of pending regulations. During Phase I, a bench-scale field test device that can be configured as an electrostatic precipitator, a pulse-jet baghouse, or a reverse-gas baghouse has been designed, built and integrated with an existing pilot-scale facility at PSCo`s Comanche Station. Up to three candidate sorbents will be injected into the flue gas stream upstream of the test device to and mercury concentration measurements will be made to determine the mercury removal efficiency for each sorbent. During the Phase II effort, component integration for the most promising dry sorbent technology shall be tested at the 5000 acfm pilot-scale.

  7. Investigation and demonstration of dry carbon-based sorbent injection for mercury control. Quarterly report, November 1, 1995--December 31, 1995

    SciTech Connect

    Hunt, T.; Sjostrom, S.

    1996-02-05

    The overall objective to this two phase program is to investigate dry carbon-based sorbents for mercury control. During Phase I, a bench-scale field test device that can simulate an electrostatic precipitator, a pulse-jet baghouse, or a reverse-gas baghouse will be designed and integrated with an existing pilot-scale facility at Public Service Company of Colorado`s (PSCo`s) Comanche station. Various sorbents will then be injected to determine the mercury removal efficiency for each. During Phase II effort, component integration of the most promising technologies shall be tested at the 5000 acfm pilot-scale. The primary task currently underway is the facility design. The design is expected to be finished in January, 1996. The facility, regardless of the particulate control module configuration, will be fitted with supply line injection port, through which mercury sorbents and SO{sub 2} control sorbents can be added to the flue gas stream.

  8. [Comparative study of carbon nanotubes and polymer composites with silver as sorbents of the influenza A and B viruses].

    PubMed

    Ivanova, V T; Ivanova, M V; Sapurina, I Yu; Burtseva, E I; Trushakova, S V; Isaeva, E I; Kirillova, E S; Stepanova, H V; Oscerco, T A; Manykin, A A

    2015-01-01

    The comparative examination of the interaction of the influenza A and B viruses and fragments of DNA with the carbon nanotubes--composites of polyaniline (PANI) nanotubes and granules containing Ag and without Ag was performed. The increased absorption of the allantois viruses and DNA was demonstrated in composites with Ag. The influence of temperature in the range of 4-36 degrees C was not found to be essential. The intensive absorption took place within the first 15 min of the contact with the sorbents. In total, the properties of the composites of PANI nanotubes + Ag 30% are the most promising for the influenza viruses and DNA absorption in water solutions.

  9. Evaluation of Commercial Off-the-Shelf Sorbents and Catalysts for Control of Ammonia and Carbon Monoxide

    NASA Technical Reports Server (NTRS)

    Luna, Bernadette; Somi, George; Winchester, J. Parker; Grose, Jeffrey; Mulloth, Lila; Perry, Jay L.

    2013-01-01

    Designers of future space vehicles envision simplifying the Atmosphere Revitalization (AR) system by combining the functions of trace contaminant (TC) control and carbon dioxide removal into one swing-bed system. Flow rates and bed sizes of the TC and CO2 systems have historically been very different. There is uncertainty about the ability of trace contaminant sorbents to adsorb adequately in high-flow or short bed length configurations, and to desorb adequately during short vacuum exposures. There is also concern about ambient ammonia levels in the absence of a condensing heat exchanger. In addition, new materials and formulations have become commercially available, formulations never evaluated by NASA for purposes of trace contaminant control. The optimal air revitalization system for future missions may incorporate a swing-bed system for carbon dioxide (CO2) and partial trace contaminant control, with a reduced-size, low-power, targeted trace contaminant system supplying the remaining contaminant removal capability. This paper describes the results of a comparative experimental investigation into materials for trace contaminant control that might be part of such a system. Ammonia sorbents and low temperature carbon monoxide (CO) oxidation catalysts are the foci. The data will be useful to designers of AR systems for future flexible path missions. This is a continuation of work presented in a prior year, with extended test results.

  10. Evaluation of Commercial Off-the-Shelf Sorbents and Catalysts for Control of Ammonia and Carbon Monoxide

    NASA Technical Reports Server (NTRS)

    Luna, Bernadette; Somi, George; Winchester, J. Parker; Grose, Jeffrey; Mulloth, Lila; Perry, Jay L.

    2010-01-01

    Designers of future space vehicles envision simplifying the Atmosphere Revitalization (AR) system by combining the functions of trace contaminant (TC) control and carbon dioxide removal into one swing-bed system. Flow rates and bed sizes of the TC and CO2 systems have historically been very different. There is uncertainty about the ability of trace contaminant sorbents to adsorb adequately in high-flow or short bed length configurations, and to desorb adequately during short vacuum exposures. There is also concern about ambient ammonia levels in the absence of a condensing heat exchanger. In addition, new materials and formulations have become commercially available, formulations never evaluated by NASA for purposes of trace contaminant control. The optimal air revitalization system for future missions may incorporate a swing-bed system for carbon dioxide (CO2) and partial trace contaminant control, with a reduced-size, low-power, targeted trace contaminant system supplying the remaining contaminant removal capability. This paper describes the results of a comparative experimental investigation into materials for trace contaminant control that might be part of such a system. Ammonia sorbents and low temperature carbon monoxide (CO) oxidation catalysts are the foci. The data will be useful to designers of AR systems for future flexible path missions. This is a continuation of work presented in a prior year, with extended test results.

  11. IN-FLIGHT CAPTURE OF ELEMENTAL MERCURY BY A CHLORINE-IMPREGNATED ACTIVATED CARBON

    EPA Science Inventory

    The paper discusses the in-flight capture of elemental mercury (Hgo) by a chlorine (C1)-impregnated activated carbon. Efforts to develop sorbents for the control of Hg emissions have demonstrated that C1-impregnation of virgin activated carbons using dilute solutions of hydrogen ...

  12. Determination of carbon monoxide with a modified zeolite sorbent and methanization-gas chromatography.

    PubMed

    Juntarawijit, C; Poovey, H G; Rando, R J

    2000-01-01

    The purpose of this study was to develop an alternative sorbent sampling technique to concentrate CO from an air sample for subsequent instrumental analysis. Y52 zeolite doped with 9.4 wt % cuprous ions was found to have high capacity, stability to air, and thermal reversibility for CO. The Cu(I)-modified zeolite was packed in glass tubes, preceded by a drying tube containing silica gel. Air was sampled through the tubes at the flow rate of 100 mL/min. Collected CO was thermally desorbed at 300 degrees C and determined by gas chromatography with reduction of CO to methane and flame ionization detection (TD-GC-CH4-FID). Breakthrough capacity of the sorbent was found to be 2.74 mg CO per gram of sorbent. For 2-L air samples containing 12.5 to 100 ppm CO and 50% relative humidity at room temperature, recovery of CO was found to be 96.6% with pooled relative standard deviation of 5.8%. The estimated detection limit for a 2-L sample was 0.2 ppm. Collected CO was stable at room temperature for 1 day and up to 7 days at 4 degrees C if the sorbent tube was flushed with helium before storage. In field testing, the ratio of CO measured by the new technique and by a reference technique was found to be 0.93 with pooled relative standard deviation of 6.3%. This unique new sorbent coupled with TD-GC-CH4-FID shows promise as a sensitive and specific alternative for measurement of CO in air.

  13. Simulation of mercury capture by activated carbon injection in incinerator flue gas. 2. Fabric filter removal.

    PubMed

    Scala, F

    2001-11-01

    Following a companion paper focused on the in-duct mercury capture in incinerator flue gas by powdered activated carbon injection, this paper is concerned with the additional mercury capture on the fabric filter cake, relevant to baghouse equipped facilities. A detailed model is presented for this process, based on material balances on mercury in both gaseous and adsorbed phases along the growing filter cake and inside the activated carbon particles,taking into account mass transfer resistances and adsorption kinetics. Several sorbents of practical interest have been considered, whose parameters have been evaluated from available literature data. The values and range of the operating variables have been chosen in order to simulate typical incinerators operating conditions. Results of simulations indicate that, contrary to the in-duct removal process, high mercury removal efficiencies can be obtained with moderate sorbent consumption, as a consequence of the effective gas/sorbent contacting on the filter. Satisfactory utilization of the sorbents is predicted, especially at long filtration times. The sorbent feed rate can be minimized by using a reactive sorbent and by lowering the filter temperature as much as possible. Minor benefits can be obtained also by decreasing the sorbent particle size and by increasing the cleaning cycle time of the baghouse compartments. Reverse-flow baghouses were more efficient than pulse-jet baghouses, while smoother operation can be obtained by increasing the number of baghouse compartments. Model results are compared with available relevant full scale data.

  14. ASSESSMENT OF LOW COST NOVEL SORBENTS FOR COAL-FIRED POWER PLANT MERCURY CONTROL

    SciTech Connect

    Sharon Sjostrom

    2004-03-01

    The injection of sorbents upstream of a particulate control device is one of the most promising methods for controlling mercury emissions from coal-fired utility boilers with electrostatic precipitators and fabric filters. Studies carried out at the bench-, pilot-, and full-scale have shown that a wide variety of factors may influence sorbent mercury removal effectiveness. These factors include mercury species, flue gas composition, process conditions, existing pollution control equipment design, and sorbent characteristics. The objective of the program is to obtain the necessary information to assess the viability of lower cost alternatives to commercially available activated carbon for mercury control in coal-fired utilities. Prior to injection testing, a number of sorbents were tested in a slipstream fixed-bed device both in the laboratory and at two field sites. Based upon the performance of the sorbents in a fixed-bed device and the estimated cost of mercury control using each sorbent, seventeen sorbents were chosen for screening in a slipstream injection system at a site burning a Western bituminous coal/petcoke blend, five were chosen for screening at a site burning a subbituminous Powder River Basin (PRB) coal, and nineteen sorbents were evaluated at a third site burning a PRB coal. Sorbents evaluated during the program were of various materials, including: activated carbons, treated carbons, other non-activated carbons, and non-carbon material. The economics and performance of the novel sorbents evaluated demonstrate that there are alternatives to the commercial standard. Smaller enterprises may have the opportunity to provide lower price mercury sorbents to power generation customers under the right set of circumstances.

  15. Regenerable sorbents for mercury capture in simulated coal combustion flue gas.

    PubMed

    Rodríguez-Pérez, Jorge; López-Antón, M Antonia; Díaz-Somoano, Mercedes; García, Roberto; Martínez-Tarazona, M Rosa

    2013-09-15

    This work demonstrates that regenerable sorbents containing nano-particles of gold dispersed on an activated carbon are efficient and long-life materials for capturing mercury species from coal combustion flue gases. These sorbents can be used in such a way that the high investment entailed in their preparation will be compensated for by the recovery of all valuable materials. The characteristics of the support and dispersion of gold in the carbon surface influence the efficiency and lifetime of the sorbents. The main factor that determines the retention of mercury and the regeneration of the sorbent is the presence of reactive gases that enhance mercury retention capacity. The capture of mercury is a consequence of two mechanisms: (i) the retention of elemental mercury by amalgamation with gold and (ii) the retention of oxidized mercury on the activated carbon support. These sorbents were specifically designed for retaining the mercury remaining in gas phase after the desulfurization units in coal power plants.

  16. Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: a review.

    PubMed

    Herrero Latorre, C; Álvarez Méndez, J; Barciela García, J; García Martín, S; Peña Crecente, R M

    2012-10-24

    New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes--due to their high adsorption and desorption capacities--have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

  17. Carbon Dioxide Capture with Ionic Liquids and Deep Eutectic Solvents: A New Generation of Sorbents.

    PubMed

    Sarmad, Shokat; Mikkola, Jyri-Pekka; Ji, Xiaoyan

    2017-01-20

    High cost and high energy penalty for CO2 uptake from flue gases are important obstacles in large-scale industrial applications, and developing efficient technology for CO2 capture from technical and economic points is crucial. Ionic liquids (ILs) show the potential for CO2 separation owing to their inherent advantages, and have been proposed as alternatives to overcome the drawbacks of conventional sorbents. Chemical modification of ILs to improve their performance in CO2 absorption has received more attention. Deep eutectic solvents (DESs) as a new generation of ILs are considered as more economical alternatives to cope with the deficiencies of high cost and high viscosity of conventional ILs. This Review discusses the potential of functionalized ILs and DESs as CO2 sorbents. Incorporation of CO2 -philic functional groups, such as amine, in cation and/or anion moiety of ILs can promot their absorption capacity. In general, the functionalization of the anion part of ILs is more effective than the cation part. DESs represent favorable solvent properties and are capable of capturing CO2 , but the research work is scarce and undeveloped compared to the studies conducted on ILs. It is possible to develop novel DESs with promising absorption capacity. However, more investigation needs to be carried out on the mechanism of CO2 sorption of DESs to clarify how these novel sorbents can be adjusted and fine-tuned to be best tailored as optimized media for CO2 capture.

  18. Contribution of individual sorbents to the control of heavy metal activity in sandy soil.

    PubMed

    Weng, L; Temminghoff, E J; Van Riemsdijk, W H

    2001-11-15

    A multisurface model is used to evaluate the contribution of various sorption surfaces to the control of heavy metal activity in sandy soil samples at pH 3.7-6.1 with different sorbent contents. This multisurface model considers soil as a set of independent sorption surfaces, i.e. organic matter (NICA-Donnan), clay silicate (Donnan), and iron hydroxides (DDL, CD-MUSIC). The activities of Cu2+, Cd2+, Zn2+, Ni2+, and Pb2+ in equilibrium with the soil have been measured using a Donnan membrane technique. The metal activities predicted by the model agree with those measured reasonably well over a wide concentration range for all the metals of interest except for Pb. The modeling results suggest that soil organic matter is the most important sorbent that controls the activity of Cu2+, Cd2+, Zn2+, and Ni2+ in these sandy soils. When metal loading is high in comparison with soil organic matter content, the contribution of clay silicates to metal binding becomes more important. Adsorption to iron hydroxides is found not significant in these samples for Cu, Cd, Zn, and Ni. However, for Pb the model estimates strong adsorption on iron hydroxides. The model predicts that acidification will not only lead to increased solution concentrations but also to a shift toward more nonspecific cation-exchange type binding especially for the metals Cd, Zn, and Ni. Lowering the pH has led to a loss of 56% of Cd, 69% of Zn, and 66% of Ni during 16 years due to increased leaching.

  19. Sorbent suppliers

    SciTech Connect

    Vedder, M.

    1994-03-01

    Sorbents are used to absorb or contain spilled and leaking chemicals, oils, lubricants and other process fluids. They are commonly used around the base of machinery in industrial applications, and in remediating oil spills on land and water. Sorbents are made from biodegradable, inorganic or synthetic materials. Organic materials include corn cobs, wood pulp, paper fiber and cotton. Inorganic materials include clay, perlite, expanded silicates and expanded mica. Synthetic sorbents are made from petroleum- or plastic-based materials such as polyurethane, polyethylene or polypropylene. Sorbents are available in a variety of forms, including pads, rolls, booms, pillows and loose particulate.

  20. Activated carbon from biomass

    NASA Astrophysics Data System (ADS)

    Manocha, S.; Manocha, L. M.; Joshi, Parth; Patel, Bhavesh; Dangi, Gaurav; Verma, Narendra

    2013-06-01

    Activated carbon are unique and versatile adsorbents having extended surface area, micro porous structure, universal adsorption effect, high adsorption capacity and high degree of surface reactivity. Activated carbons are synthesized from variety of materials. Most commonly used on a commercial scale are cellulosic based precursors such as peat, coal, lignite wood and coconut shell. Variation occurs in precursors in terms of structure and carbon content. Coir having very low bulk density and porous structure is found to be one of the valuable raw materials for the production of highly porous activated carbon and other important factor is its high carbon content. Exploration of good low cost and non conventional adsorbent may contribute to the sustainability of the environment and offer promising benefits for the commercial purpose in future. Carbonization of biomass was carried out in a horizontal muffle furnace. Both carbonization and activation were performed in inert nitrogen atmosphere in one step to enhance the surface area and to develop interconnecting porosity. The types of biomass as well as the activation conditions determine the properties and the yield of activated carbon. Activated carbon produced from biomass is cost effective as it is easily available as a waste biomass. Activated carbon produced by combination of chemical and physical activation has higher surface area of 2442 m2/gm compared to that produced by physical activation (1365 m2/gm).

  1. Sorbent Scoping Studies

    SciTech Connect

    Chancellor, Christopher John

    2016-11-14

    The Los Alamos National Laboratory – Carlsbad Operations (LANL-CO) office was tasked by the DOE CBFO, Office of the Manager to: • Perform a review of the acceptable knowledge (AK) to identify the oxidizers and sorbents in transuranic (TRU) waste streams. • Conduct scoping studies on the oxidizers and sorbents identified in AK review to inform the Quality Level 1 (QL1) testing. • Conduct a series of QL1 tests to provide the scientific data to support a basis of knowledge document for determining the criteria for: 1) accepting waste at the Waste Isolation Pilot Plant (WIPP) without treatment, 2) determining waste that will require treatment, and 3) if treatment is required, how the treatment must be performed. The purpose of this report is to present the results of the AK review of sorbents present in active waste streams, provide a technical analysis of the sorbent list, report the results of the scoping studies for the fastest burning organic sorbent, and provide the list of organic and inorganic sorbents to be used in the development of a Test Plan for Preparation and Testing of Sorbents Mixed with Oxidizer found in Transuranic Waste (DWT-TP-001). The companion report, DWT-RPT-001, Oxidizer Scoping Studies, has similar information for oxidizers identified during the AK review of TRU waste streams. The results of the oxidizer and sorbent scoping studies will be used to inform the QL1 test plan. The QL1 test results will support the development of a basis of knowledge document that will evaluate oxidizing chemicals and sorbents in TRU waste and provide guidance for treatment.

  2. Experiment and modeling of CO{sub 2} capture from flue gases at high temperature in a fluidized bed reactor with Ca-based sorbents

    SciTech Connect

    Fan Fang; Zhen-Shan Li; Ning-Sheng Cai

    2009-01-15

    The cyclic CO{sub 2} capture and CaCO{sub 3} regeneration characteristics in a small fluidized bed reactor were experimentally investigated with limestone and dolomite sorbents. Kinetic rate constants for carbonation and calcination were determined using thermogravimetric analysis (TGA) data. Mathematical models developed to model the Ca-based sorbent multiple cycles of CO{sub 2} capture and calcination in the bubbling fluidized bed reactor agreed with the experimental data. The experimental and simulated results showed that the CO{sub 2} in flue gases could be absorbed efficiently by limestone and dolomite. The time for high-efficiency CO{sub 2} capture decreased with an increasing number of cycles because of the loss of sorbent activity, and the final CO{sub 2} capture efficiency remained nearly constant as the sorbent reached its final residual capture capacity. In a continuous carbonation and calcination system, corresponding to the sorbent activity loss, the carbonation kinetic rates of sorbent undergoing various cycles are different, and the carbonation kinetic rates of sorbent circulating N times in the carbonation/calcination cycles are also different because of the different residence time of sorbent in the carbonator. Therefore, the average carbonation rate was given based on the mass balance and exit age distribution for sorbent in the carbonator. The CO{sub 2} capture characteristics in a continuous carbonation/calcination system were predicted, taking into consideration the mass balance, sorbent circulation rate, sorbent activity loss, and average carbonation kinetic rate, to give useful information for the reactor design and operation of multiple carbonation/calcination reaction cycles. 27 refs., 15 figs., 1 tab.

  3. Long Duration Sorbent Testbed

    NASA Technical Reports Server (NTRS)

    Knox, James; Long, David; Miller, Lee; Thomas, John; Cmarik, Greg; Howard, David

    2016-01-01

    The LDST is a flight experiment demonstration designed to expose current and future candidate carbon dioxide removal system sorbents to an actual crewed space cabin environment to assess and compare sorption working capacity degradation resulting from long term operation. An analysis of sorbent materials returned to earth after approximately one year of operation in the International Space Station's (ISS) Carbon Dioxide Removal Assembly (CDRA) indicated as much as a 70% loss of working capacity of the silica gel desiccant material at the extreme system inlet location, with a gradient of capacity loss down the bed. The primary science objective is to assess the degradation of potential sorbents for exploration class missions and ISS upgrades when operated in a true crewed space cabin environment. A secondary objective is to compare degradation of flight test to a ground test unit with contaminant dosing to determine applicability of ground testing.

  4. Dispersive micro solid-phase extraction of triazines from waters using oxidized single-walled carbon nanohorns as sorbent.

    PubMed

    Jiménez-Soto, Juan Manuel; Cárdenas, Soledad; Valcárcel, Miguel

    2012-07-06

    This article evaluates the usefulness of dispersed single-walled carbon nanohorns as sorbent for the isolation and preconcentration of triazines from waters. For this purpose, the carbon nanoparticles were oxidized to increase their solubility in aqueous media in order to obtain a stable dispersion that can be used as extractant of the selected pollutants. Then, 1 mL of the dispersion containing the oxidized single-walled carbon nanohorns at a concentration of 0.2 g/L was added to 10 mL of sample and stirred for 2 min using a vortex. Then, the whole volume was passed through a disposable 0.45 μm Nylon filter which retained the nanoparticles enriched with the triazines. Further elution with methanol permitted the gas chromatographic analysis of the analytes and subsequent identification and quantification by mass spectrometry working under the selected ion monitoring mode (SIM). The limits of detection (LODs) were in low nanogram per liter level, which allowed the detection of the selected triazines at the concentration stated by legislation. The precision of the method, calculated as relative standard deviation, was acceptable in all instances. Finally, the recovery study carried out in different water samples provided average values between 87% and 94%. The results obtained revealed the applicability of oxidized single-walled carbon nanohorns for the proposed analytical problem.

  5. Adsorption of Polycyclic Aromatic Hydrocarbons (PAHS) from Aqueous Solutions on Different Sorbents

    NASA Astrophysics Data System (ADS)

    Smol, Marzena; Włodarczyk-Makuła, Maria; Włóka, Dariusz

    2014-12-01

    This paper presents the results of the possibility and effectiveness of PAHs removal from a model aqueous solution, during the sorption on the selected sorbents. Six PAHs (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene) listed by EPA for the analysis in the environmental samples were determined. Model aqueous solution was prepared with RESTEK 610 mix PAHs standard. After the sorption process, decrease in the concentration of individual hydrocarbons was observed. The removal percentage was dependent on the type of sorbent (quartz sand, mineral sorbent, activated carbon). The highest efficiency (98.1%) was observed for activated carbon.. The results shows that the sorption processes can be used in aqueous solutions treatment procedures.

  6. Carbon dioxide capture by functionalized solid amine sorbents with simulated flue gas conditions.

    PubMed

    Liu, Yamin; Ye, Qing; Shen, Mei; Shi, Jingjin; Chen, Jie; Pan, Hua; Shi, Yao

    2011-07-01

    A novel solid amine sorbent was prepared using KIT-6-type mesoporous silica modified with tetraethylenepentamine (TEPA). Its adsorption behavior toward CO(2) from simulated flue gases is investigated using an adsorption column. The adsorption capacities at temperatures of 303, 313, 333, 343, and 353 K are 2.10, 2.29, 2.58, 2.85, and 2.71 mmol g(-1), respectively. Experimental adsorption isotherms were obtained, and the average isosteric heat of adsorption was 43.8 kJ/mol. The adsorption capacity increases to 3.2 mmol g(-1) when the relative humidity (RH) of the simulated flue gas reaches 37%. The adsorption capacity is inhibited slightly by the presence of SO(2) at concentrations lower than 300 ppm but is not significantly influenced by NO at concentrations up to 400 ppm. The adsorbent is completely regenerated in 10 min at 393 K and a pressure of 5 KPa, with expected consumption energy of about 1.41 MJ kg(-1) CO(2). The adsorption capacity remains almost the same after 10 cycles of adsorption/regeneration with adsorption conditions of 10 vol % CO(2), 100 ppm SO(2), 200 ppm NO, 100% relative humidity, and a temperature of 393 K. The solid amine sorbent, KIT-6(TEPA), performs excellently for CO(2) capture and its separation from flue gas.

  7. LOW CONCENTRATION MERCURY SORPTION MECHANISMS AND CONTROL BY CALCIUM-BASED SORBENTS; APPLICATION IN COAL-FIRED PROCESSES

    EPA Science Inventory

    The capture of elemental mercury (Hgo) and mercuric chloride (HgCl2) by three types of calcium (Ca)-based sorbents was examined in this bench-scale study under conditions prevalent in coal fired utilities. Ca-based sorbent performances were compared to that of an activated carbon...

  8. Sn-Mn binary metal oxides as non-carbon sorbent for mercury removal in a wide-temperature window.

    PubMed

    Xie, Jiangkun; Xu, Haomiao; Qu, Zan; Huang, Wenjun; Chen, Wanmiao; Ma, Yongpeng; Zhao, Songjian; Liu, Ping; Yan, Naiqiang

    2014-08-15

    A series of Sn-Mn binary metal oxides were prepared through co-precipitation method. The sorbents were characterized by powder X-ray diffraction (powder XRD), transmission electronic microscopy (TEM), H2-temperature-programmed reduction (H2-TPR) and NH3-temperature-programmed desorption (NH3-TPD) methods. The capability of the prepared sorbents for mercury adsorption from simulated flue gas was investigated by fixed-bed experiments. Results showed that mercury adsorption on pure SnO2 particles was negligible in the test temperature range, comparatively, mercury capacity on MnOx at low temperature was relative high, but the capacity would decrease significantly when the temperature was elevated. Interestingly, for Sn-Mn binary metal oxide, mercury capacity increased not only at low temperature but also at high temperature. Furthermore, the impact of SO2 on mercury adsorption capability of Sn-Mn binary metal oxides was also investigated and it was noted that the effect at low temperature was different comparing with that of high temperature. The mechanism was investigated by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs). Moreover, a mathematic model was built to calculate mercury desorption activation energy from Sn to Mn binary metal oxides.

  9. Surface modification of activated carbons for CO 2 capture

    NASA Astrophysics Data System (ADS)

    Pevida, C.; Plaza, M. G.; Arias, B.; Fermoso, J.; Rubiera, F.; Pis, J. J.

    2008-09-01

    The reduction of anthropogenic CO 2 emissions to address the consequences of climate change is a matter of concern for all developed countries. In the short term, one of the most viable options for reducing carbon emissions is to capture and store CO 2 at large stationary sources. Adsorption with solid sorbents is one of the most promising options. In this work, two series of materials were prepared from two commercial activated carbons, C and R, by heat treatment with gaseous ammonia at temperatures in the 200-800 °C range. The aim was to improve the selectivity and capacity of the sorbents to capture CO 2, by introducing basic nitrogen-functionalities into the carbons. The sorbents were characterised in terms of texture and chemical composition. Their surface chemistry was studied through temperature-programmed desorption tests and X-ray photoelectron spectroscopy. The capture performance of the carbons was evaluated by using a thermogravimetric analyser to record mass uptakes by the samples when exposed to a CO 2 atmosphere.

  10. Activated carbon material

    DOEpatents

    Evans, A. Gary

    1978-01-01

    Activated carbon particles for use as iodine trapping material are impregnated with a mixture of selected iodine and potassium compounds to improve the iodine retention properties of the carbon. The I/K ratio is maintained at less than about 1 and the pH is maintained at above about 8.0. The iodine retention of activated carbon previously treated with or coimpregnated with triethylenediamine can also be improved by this technique. Suitable flame retardants can be added to raise the ignition temperature of the carbon to acceptable standards.

  11. Sorption of mercury (II) and atrazine by biochar, modified biochars and biochar based activated carbon in aqueous solution.

    PubMed

    Tan, Guangcai; Sun, Weiling; Xu, Yaru; Wang, Hongyuan; Xu, Nan

    2016-07-01

    Corn straw biochar (BC) was used as a precursor to produce Na2S modified biochar (BS), KOH modified biochar (BK) and activated carbon (AC). Experiments were conducted to compare the sorption capacity of these sorbents for aqueous Hg (II) and atrazine existed alone or as a mixture. In comparison to BC, the sorption capacity of BS, BK and AC for single Hg (II) increased by 76.95%, 32.12% and 41.72%, while that for atrazine increased by 38.66%, 46.39% and 47 times, respectively. When Hg (II) and atrazine coexisted in an aqueous solution, competitive sorption was observed on all these sorbents. Sulfur impregnation was an efficient way to enhance the Hg (II) removal due to the formation of HgS precipitate, and oxygen-containing functional groups on the sorbents also contributed to Hg (II) sorption. Activated carbon was the best sorbent for atrazine removal because of its extremely high specific surface area.

  12. Effects of Natural Organic Matter on PCB-Activated Carbon Sorption Kinetics: Implications for Sediment Capping Applications

    EPA Science Inventory

    In-situ capping of polychlorinated biphenyl (PCB) contaminated sediments with layers of sorbents such as activated carbon has been proposed, but several technical questions remain regarding long-term effectiveness. An activated carbon amended sediment cap was mimicked in laborat...

  13. Use of bentonite and activated carbon in controlled release formulations of carbofuran.

    PubMed

    Fernández-Pérez, M; Villafranca-Sánchez, M; Flores-Céspedes, F; Garrido-Herrera, F J; Pérez-García, S

    2005-08-24

    Controlled release systems (CRS), unlike the conventional formulations, facilitate a gradual and controlled discharge of the pesticides, reducing the losses by evaporation and leaching and minimizing pesticide pollution. In this study, carbofuran-an insecticide-nematicide identified as a groundwater pollutant-was incorporated in alginate-based granules to obtain controlled release properties. The effect on carbofuran release rate caused by the incorporation of bentonite, activated carbon, and different mixtures of both sorbents in alginate basic formulation was studied by immersion of the granules in water. The water uptake, sorption capacity of the sorbent, permeability, and time taken for 50% of the active ingredient to be released into water, T(50), were calculated by the comparison of the preparations. T(50) values were higher for those formulations containing bentonite and/or activated carbon (T(50) values range from 14.76 h for the alginate formulation containing only bentonite as the sorbent to 29.5 weeks for the alginate formulation containing only activated carbon as the sorbent) than for the preparation without these sorbents (11.72 h). On the basis of a parameter of an empirical equation used to fit the insecticide-nematicide release data, it appears that the release of carbofuran from the various formulations into water is controlled by a diffusion mechanism. The sorption capacity of the sorbents for carbofuran was the most important factor modulating carbofuran release. In addition, it was observed that there is a linear correlation of the T(50) values and the content of activated carbon in dry granules.

  14. Characteristics of mercury desorption from sorbents at elevated temperatures

    SciTech Connect

    Ho, T.C.; Yang, P.; Kuo, T.H.; Hopper, J.R.

    1998-12-31

    This study investigated the dynamic desorption characteristics of mercury during the thermal treatment of mercury-loaded sorbents at elevated temperatures under fixed-bed operations. Experiments were carried out in a 25.4 mm ID quartz bed enclosed in an electric furnace. Elemental mercury and mercuric chloride were tested with activated carbon and bauxite. The experimental results indicated that mercury desorption from sorbents was strongly affected by the desorption temperature and the mercury-sorbent pair. Elemental mercury was observed to desorb faster than mercuric chloride and activated carbon appeared to have higher desorption limits than bauxite at low temperatures. A kinetic model considering the mechanisms of surface equilibrium, pore diffusion and external mass transfer was proposed to simulate the observed desorption profiles. The model was found to describe reasonably well the experimental results.

  15. CO{sub 2} absorption using dry potassium-based sorbents with different supports

    SciTech Connect

    Chuanwen Zhao; Xiaoping Chen; Changsui Zhao

    2009-09-15

    The CO{sub 2} capture characteristics of dry potassium-based sorbents were investigated with thermogravimetric analysis (TGA) and a bubbling fluidized-bed reactor. Potassium-based sorbents were prepared by impregnation with potassium carbonate on supports such as coconut activated charcoal (AC1), coal active carbon (AC2), silica gel (SG), and activated alumina (Al{sub 2}O{sub 3}). Sorbents such as K{sub 2}CO{sub 3}/AC1, K{sub 2}CO{sub 3}/AC2, and K{sub 2}CO{sub 3}/Al{sub 2}O{sub 3} showed excellent carbonation capacity; The total conversion rates of those sorbents were 97.2, 95.9, and 95.2%, respectively in the TG test, and 89.2, 87.9, and 87.6%, respectively, in the fluidized-bed test. However, K{sub 2}CO{sub 3}/SG showed poor carbonation capacity, the total conversion rates were only 34.5 and 18.8%, respectively, in TG and fluidized-bed tests. The differences in carbonation capacity of those sorbents were analyzed by studying the microscopic structure and crystal structure of the supports and the sorbents with X-ray diffraction, scanning electron microscopy, and N{sub 2} adsorption tests. 23 refs., 10 figs.

  16. Development of new sorbents to remove mercury and selenium from flue gas. Final report, September 1, 1993--August 31, 1994

    SciTech Connect

    Shiao, S.Y.

    1995-02-01

    Mercury (Hg) and selenium (Se) are two of the volatile trace metals in coal, which are often not captured by conventional gas clean up devices of coal-fired boilers. An alternative is to use sorbents to capture the volatile components of trace metals after coal combustion. In this project sorbent screening tests were performed in which ten sorbents were selected to remove metallic mercury in N{sub 2}. These sorbents included activated carbon, char prepared from Ohio No. 5 coal, molecular sieves, silica gel, aluminum oxide, hydrated lime, Wyoming bentonite, kaolin, and Amberite IR-120 (an ion-exchanger). The sorbents were selected based on published information and B&W`s experience on mercury removal. The promising sorbent was then selected and modified for detailed studies of removal of mercury and selenium compounds. The sorbents were tested in a bench-scale adsorption facility. A known amount of each sorbent was loaded in the column as a packed bed. A carrier gas was bubbled through the mercury and selenium compounds. The vaporized species were carried by the gas and went through the sorbent beds. The amount of mercury and selenium compounds captured by the sorbents was determined by atomic absorption. Results are discussed.

  17. Energy and environmental research emphasizing low-rank coal: Task 5.7, Coal char fuel evaporation canister sorbent

    SciTech Connect

    Aulich, T.R.; Grisanti, A.A.; Knudson, C.L.

    1995-08-01

    Atomobile evaporative emission canisters contain activated carbon sorbents that trap and store fuel vapors emitted from automobile fuel tanks during periods of hot ambient temperatures and after engine operation. When a vehicle is started, combustion air is pulled through the canister, and adsorbed vapors are removed from the sorbent and routed to the intake manifold for combustion along with fuel from the tank. The two primary requirements of an effective canister sorbent are that (1) it must be a strong enough adsorbent to hold on to the fuel vapors that contact it and (2) it must be a weak enough adsorbent to release the captured vapors in the presence of the airflow required by the engine for fuel combustion. Most currently available commercial canister sorbents are made from wood, which is reacted with phosphoric acid and heat to yield an activated carbon with optimum pore size for gasoline vapor adsorption. The objectives of Task 5.7 were to (1) design and construct a test system for evaluating the performance of different sorbents in trapping and releasing butane, gasoline, and other organic vapors; (2) investigate the use of lignite char as an automobile fuel evaporation canister sorbent; (3) compare the adsorbing and desorbing characteristics of lignite chars with those of several commercial sorbents; and (4) investigate whether the presence of ethanol in fuel vapors affects sorbent performance in any way. Tests with two different sorbents (a wood-derived activated carbon and a lignite char) showed that with both sorbents, ethanol vapor breakthrough took about twice as long as hydrocarbon vapor breakthrough. Possible reasons for this, including an increased sorbent affinity for ethanol vapors, will be investigated. If this effect is real (i.e., reproducible over an extensive series of tests under varying conditions), it may help explain why ethanol vapor concentrations in SHED test evaporative emissions are often lower than would be expected.

  18. Sorption of metal ions from multicomponent aqueous solutions by activated carbons produced from waste

    SciTech Connect

    Tikhonova, L.P.; Goba, V.E.; Kovtun, M.F.; Tarasenko, Y.A.; Khavryuchenko, V.D.; Lyubchik, S.B.; Boiko, A.N.

    2008-08-15

    Activated carbons produced by thermal treatment of a mixture of sunflower husks, low-grade coal, and refinery waste were studied as adsorbents of transition ion metals from aqueous solutions of various compositions. The optimal conditions and the mechanism of sorption, as well as the structure of the sorbents, were studied.

  19. Sorption of chlorophenols from aqueous solution by granular activated carbon, filter coal, pine and hardwood.

    PubMed

    Hossain, G S M; McLaughlan, R G

    2012-09-01

    Wood and coal, as low-cost sorbents, have been evaluated as an alternative to commercial granular activated carbon (GAC) for chlorophenol removal. Kinetic experiments indicated that filter coal had a significantly lower rate of uptake (approximately 10% of final uptake was achieved after three hours) than the other sorbents, owing to intra-particle diffusion limitations. The data fitted a pseudo-second-order model. Sorption capacity data showed that GAC had a high sorption capacity (294-467 mg g(-1)) compared with other sorbents (3.2-7.5 mg(g-1)). However, wood and coal had a greater sorption capacity per unit surface area than GAC. Sorption equilibrium data was best predicted using a Freundlich adsorption model. The sorption capacity for all sorbents was 2-chlorophenol < 4-chlorophenol < 2, 4-dichlorophenol, which correlates well with solute hydrophobicity, although the relative differences were much less for coal than the other sorbents. The results showed that pine, hardwood and filter coal can be used as sorbent materials for the removal of chlorophenol from water; however, kinetic considerations may limit the application of filter coal.

  20. ACTIVATION AND REACTIVITY OF NOVEL CALCIUM-BASED SORBENTS FOR DRY SO2 CONTROL IN BOILERS

    EPA Science Inventory

    Chemically modified calcium hydroxide (Ca(OH)2) sorbents developed in the U.S. Environmental Protection Agency's Air and Energy Engineering Research Laboratory (AEERL) for sulfur dioxide (SO2) control in utility boilers were tested in an electrically heated, bench-scale isotherma...

  1. A Magnetic Carbon Sorbent for Radioactive Material from the Fukushima Nuclear Accident

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Daizo; Furukawa, Kazumi; Takasuga, Masaya; Watanabe, Koki

    2014-08-01

    Here we present the first report of a carbon-γ-Fe2O3 nanoparticle composite of mesoporous carbon, bearing COOH- and phenolic OH- functional groups on its surface, a remarkable and magnetically separable adsorbent, for the radioactive material emitted by the Fukushima Daiichi nuclear power plant accident. Contaminated water and soil at a level of 1,739 Bq kg-1 (134Cs and 137Cs at 509 Bq kg-1 and 1,230 Bq kg-1, respectively) and 114,000 Bq kg-1 (134Cs and 137Cs at 38,700 Bq kg-1 and 75,300 Bq kg-1, respectively) were decontaminated by 99% and 90% respectively with just one treatment carried out in Nihonmatsu city in Fukushima. Since this material is remarkably high performance, magnetically separable, and a readily applicable technology, it would reduce the environmental impact of the Fukushima accident if it were used.

  2. Tunable polymeric sorbent materials for fractionation of model naphthenates.

    PubMed

    Mohamed, Mohamed H; Wilson, Lee D; Headley, John V

    2013-04-04

    The sorption properties are reported for several examples of single-component carboxylic acids representing naphthenic acids (NAs) with β-cyclodextrin (β-CD) based polyurethane sorbents. Seven single-component examples of NAs were chosen with variable z values, carbon number, and chemical structure as follows: 2-hexyldecanoic acid (z = 0 and C = 16; S1), n-caprylic acid (z = 0 and C = 8; S2), trans-4-pentylcyclohexanecarboxylic acid (z = -2 and C = 12; S3), 4-methylcyclohexanecarboxylic acid (z = -2 and C = 8; S4), dicyclohexylacetic acid (z = -4; C = 14; S5), 4-pentylbicyclo[2.2.2]octane-1-carboxylic acid (z = -4; C = 14; S6), and lithocholic acid (z = -6; C = 24; S7). The copolymer sorbents were synthesized at three relative β-CD:diisocyanate mole ratios (i.e., 1:1, 1:2, and 1:3) using 4,4'-dicyclohexylmethane diisocyanate (CDI) and 4,4'-diphenylmethane diisocyanate (MDI). The sorption properties of the copolymer sorbents were characterized using equilibrium sorption isotherms in aqueous solution at pH 9.00 with electrospray ionization mass spectrometry. The equilibrium fraction of the unbound carboxylate anions was monitored in the aqueous phase. The sorption properties of the copolymer sorbents (i.e., Qm) were obtained from the Sips isotherm model. The Qm values generally decrease as the number of accessible β-CD inclusion sites in the copolymer framework decreases. The chemical structure of the adsorbates played an important role in their relative uptake, as evidenced by the adsorbate lipophilic surface area (LSA) and the involvement of hydrophobic effects. The copolymers exhibit molecular selective sorption of the single-component carboxylates in mixtures which suggests their application as sorbents for fractionation of mixtures of NAs. By comparison, granular activated carbon (GAC) and chitosan sorbents did not exhibit any significant molecular selective sorption relative to the copolymer materials; however, evidence of variable sorption capacity was

  3. A Magnetic Carbon Sorbent for Radioactive Material from the Fukushima Nuclear Accident

    PubMed Central

    Yamaguchi, Daizo; Furukawa, Kazumi; Takasuga, Masaya; Watanabe, Koki

    2014-01-01

    Here we present the first report of a carbon-γ-Fe2O3 nanoparticle composite of mesoporous carbon, bearing COOH- and phenolic OH- functional groups on its surface, a remarkable and magnetically separable adsorbent, for the radioactive material emitted by the Fukushima Daiichi nuclear power plant accident. Contaminated water and soil at a level of 1,739 Bq kg−1 (134Cs and 137Cs at 509 Bq kg−1 and 1,230 Bq kg−1, respectively) and 114,000 Bq kg−1 (134Cs and 137Cs at 38,700 Bq kg−1 and 75,300 Bq kg−1, respectively) were decontaminated by 99% and 90% respectively with just one treatment carried out in Nihonmatsu city in Fukushima. Since this material is remarkably high performance, magnetically separable, and a readily applicable technology, it would reduce the environmental impact of the Fukushima accident if it were used. PMID:25116650

  4. Engineered Structured Sorbents for the Adsorption of Carbon Dioxide and Water Vapor from Manned Spacecraft Atmospheres: Applications and Modeling 2007/2008

    NASA Technical Reports Server (NTRS)

    Knox, James C.; Howard, David F.; Perry, Jay L.

    2007-01-01

    In NASA s Vision for Space Exploration, humans will once again travel beyond the confines of earth s gravity, this time to remain there for extended periods. These forays will place unprecedented demands on launch systems. They must not only blast out of earth s gravity well as during the Apollo moon missions, but also launch the supplies needed to sustain a larger crew over much longer periods. Thus all spacecraft systems, including those for the separation of metabolic carbon dioxide and water from a crewed vehicle, must be minimized with respect to mass, power, and volume. Emphasis is also placed on system robustness both to minimize replacement parts and ensure crew safety when a quick return to earth is not possible. This paper describes efforts to improve on typical packed beds of sorbent pellets by making use of structured sorbents and alternate bed configurations to improve system efficiency and reliability. The development efforts described offer a complimentary approach combining testing of subscale systems and multiphysics computer simulations to characterize the regenerative heating substrates and evaluation of engineered structured sorbent geometries. Mass transfer, heat transfer, and fluid dynamics are included in the transient simulations.

  5. Evaluation of activated carbon for control of mercury from coal-fired boilers

    SciTech Connect

    Miller, S.; Laudal, D.; Dunham, G.

    1995-11-01

    The ability to remove mercury from power plant flue gas may become important because of the Clean Air Act amendments` requirement that the U.S. Environmental Protection Agency (EPA) assess the health risks associated with these emissions. One approach for mercury removal, which may be relatively simple to retrofit, is the injection of sorbents, such as activated carbon, upstream of existing particulate control devices. Activated carbon has been reported to capture mercury when injected into flue gas upstream of a spray dryer baghouse system applied to waste incinerators or coal-fired boilers. However, the mercury capture ability of activated carbon injected upstream of an electrostatic precipitator (ESP) or baghouse operated at temperatures between 200{degrees} and 400{degrees}F is not well known. A study sponsored by the U.S. Department of Energy and the Electric power Research Institute is being conducted at the University of North Dakota Energy & Environmental Research Center (EERC) to evaluate whether mercury control with sorbents can be a cost-effective approach for large power plants. Initial results from the study were reported last year. This paper presents some of the recent project results. Variables of interest include coal type, sorbent type, sorbent addition rate, collection media, and temperature.

  6. Assessing sorbent injection mercury control effectiveness in flue gas streams

    USGS Publications Warehouse

    Carey, T.R.; Richardson, C.F.; Chang, R.; Meserole, F.B.; Rostam-Abadi, M.; Chen, S.

    2000-01-01

    One promising approach for removing mercury from coal-fired, utility flue gas involves the direct injection of mercury sorbents. Although this method has been effective at removing mercury in municipal waste incinerators, tests conducted to date on utility coal-fired boilers show that mercury removal is much more difficult in utility flue gas. EPRI is conducting research to investigate mercury removal using sorbents in this application. Bench-scale, pilot-scale, and field tests have been conducted to determine the ability of different sorbents to remove mercury in simulated and actual flue gas streams. This paper focuses on recent bench-scale and field test results evaluating the adsorption characteristics of activated carbon and fly ash and the use of these results to develop a predictive mercury removal model. Field tests with activated carbon show that adsorption characteristics measured in the lab agree reasonably well with characteristics measured in the field. However, more laboratory and field data will be needed to identify other gas phase components which may impact performance. This will allow laboratory tests to better simulate field conditions and provide improved estimates of sorbent performance for specific sites. In addition to activated carbon results, bench-scale and modeling results using fly ash are presented which suggest that certain fly ashes are capable of adsorbing mercury.

  7. Modifying sorbents in controlled release formulations to prevent herbicides pollution.

    PubMed

    Flores Céspedes, F; Villafranca Sánchez, M; Pérez García, S; Fernández Pérez, M

    2007-10-01

    The herbicides chloridazon and metribuzin, identified as groundwater pollutants, were incorporated in alginate-based granules to obtain controlled release properties. In this research the effect of incorporation of sorbents such as bentonite, anthracite and activated carbon in alginate basic formulation were not only studied on encapsulation efficiency but also on the release rate of herbicides which was studied using water release kinetic tests. In addition, sorption studies of herbicides with bentonite, anthracite and activated carbon were made. The kinetic experiments of chloridazon and metribuzin release in water have shown that the release rate is higher in metribuzin systems than in those prepared with chloridazon, which has lower water solubility. Besides, it can be deduced that the use of sorbents reduces the release rate of the chloridazon and metribuzin in comparison to the technical product and to the alginate formulation without sorbents. The highest decrease in release rate corresponds to the formulations prepared with activated carbon as a sorbent. The water uptake, permeability, and time taken for 50% of the active ingredient to be released into water, T(50), were calculated to compare the formulations. On the basis of a parameter of an empirical equation used to fit the herbicide release data, the release of chloridazon and metribuzin from the various formulations into water is controlled by a diffusion mechanism. Sorption capacity of the sorbents for chloridazon and metribuzin, ranging from 0.53mgkg(-1) for the metribuzin sorption on bentonite to 2.03x10(5)mgkg(-1) for the sorption of chloridazon on the activated carbon, was the most important factor modulating the herbicide release.

  8. Kinetics of Mn-based sorbents for hot coal gas desulfurization. Quarterly progress report, July 15, 1995--September 15, 1995

    SciTech Connect

    Hepworth, M.T.

    1995-09-15

    The Morgantown Energy Technology Center (METC) of the U.S. Department of Energy (DOE) is actively pursuing the development of reliable and cost-effective processes to clean coal gasifier gases for application to integrated gasification combined cycle (IGCC) and molten carbonate fuel cell (MCFC) power plants. A large portion of gas cleanup research has been directed towards hot gas desulfurization using Zn-based sorbents. However, zinc titinate sorbents undergo reduction to the metal at temperatures approaching 700{degrees}C. In addition, sulfate formation during regeneration leads to spalling of reactive 293 surfaces. Due to zinc-based sorbent performance, METC has shown interest in formulating and testing manganese-based sorbents. Westmoreland and Harrison evaluated numerous candidate sulfur sorbents and identified Mn as a good candidate. Later, Turkdogan and Olsson tested manganese-based sorbents which demonstrated superior desulfurization capacity under high temperatures, and reducing conditions. Recently, Ben-Slimane and Hepworth conducted several studies on formulating Mn-sorbents and desulfurizing a simulated fuel gas. Although thermodynamics predicts higher over-pressures with Mn verses Zn, under certain operating conditions Mn-based sorbents may obtain < 20 ppmv. In addition, the manganese-sulfur-oxygen (Mn-S-O) system does not reduce to the metal under even highly reducing gases at high temperatures (550-900{degrees}C). Currently, many proposed IGCC processes include a water quench prior to desulfurization. This is for two reasons; limitations in the process hardware (1000{degrees}C), and excessive Zn-based sorbent loss (about 700{degrees}C). With manganese the water quench is obviated due to sorbent loss, as Mn-based sorbents have been shown to retain reactivity under cycling testing at 900{degrees}C. This reduces system hardware, and increases thermal efficiency while decreasing the equilibrium H{sub 2}S over-pressure obtainable with a manganese sorbent.

  9. An emerging class of volatile organic compound sorbents: Friedel-Crafts modified polystyrenes. 2: Performance comparison with commercially-available sorbents and isotherm analysis

    SciTech Connect

    Simpson, E.J.; Koros, W.J.; Schechter, R.S.

    1996-12-01

    The performance of Friedel-Crafts modified polystyrene (FCMPS) as a volatile organic compound (VOC) sorbent is compared with commercially available polymers and activated carbon. Detailed analyses of the equilibrium isotherms are presented, including vapor phase isotherm temperature dependence and isosteric heats of sorption. Although significant absorption contributions are observed for the polymeric sorbents of this study, the data are mathematically well represented by Polanyi potential analysis. FCMPS can be synthesized with desirable performance qualities such as ultimate VOC sorption capacity of {approximately}2 mL/g, competitively high capacity in dilute streams versus activated carbon, insensitivity to humidity in vapor phase applications, and comparative ease of regeneration.

  10. Utilization and Conversion of Sewage Sludge as Metal Sorbent

    NASA Astrophysics Data System (ADS)

    Gong, Xu Dong; Li, Loretta Y.

    2013-04-01

    Most biosolids are disposed on land. With improvements in wastewater treatment processes and upgrading of treatment plants across Canada, biosolids generation will increase dramatically. These biosolids will need to be dealt with because they contain various contaminants, including heavy metals and several classes of emerging contaminants. A number of researchers have recently focused on preparation of sewage sludge-based adsorbents by carbonation, physical activation and chemical activation for decontamination of air and wastewater. These previous studies have indicated that sludge-based activated carbon can have good adsorption performance for organic substances in dye wastewater. The overall results suggest that activated carbon from sewage sludge can produce a useful adsorbent, while also reducing the amount of sewage sludge to be disposed. However, sludge-derived activated carbon has not been extensively studied, especially for adsorption of heavy metal ions in wastewater and for its capacity to remove emerging contaminants, such as poly-fluorinated compounds (PFCs). Previous research has indicated that commercial activated carbons adsorb organic compounds more efficiently than heavy metal ions. 45 Activated carbon can be modified to enhance its adsorption capacity for special heavy metal ions,46 e.g. by addition of inorganic and organic reagents. The modifications which are successful for commercial activated carbon should also be effective for sludge-derived activated carbon, but this needs to be confirmed. Our research focuses on (a) investigation of techniques for converting sewage sludge (SS) to activated carbon (AC) as sorbents; (b) exploration of possible modification of the activated carbon (MAC) to improve its sorption capacity; (c) examination of the chemical stability of the activated carbon and the leachability of contaminants from activated carbon,; (d) comparison of adsorptivity with that of other sorbents. Based on XRD and FT-IR, we successfully

  11. Development of bamboo-derived sorbents for mercury removal in gas phase.

    PubMed

    Siddiqui, Naved; Don, Jarlen; Mondal, Kanchan; Mahajan, Ajay

    2011-01-01

    Activated carbon sorbents were synthesized from bamboo precursors by carbonization in an inert atmosphere followed by physiochemical activation with carbon dioxide and finally acidulation in hydrochloric acid. Bamboo strips with and without the epidermal tissue (bark) were used. The morphology and specific surface area changes due to the treatment were analysed. The adsorption characteristics of these sorbents after each stage of treatment were also analysed and the data were correlated to the changes in the physical characteristics of the sorbents. Kinetic studies were conducted on these samples. The adsorption equilibrium and kinetics of elemental mercury adsorption on these carbons were evaluated at room temperature. Elemental mercury uptake at different sorbent loading and initial elemental mercury concentrations were examined. The adsorption rate constants and the mass transfer constants were estimated for the sorbents prepared under different conditions. Adsorption isotherms of the elemental mercury on these activated carbons were determined and correlated with Langmuir and Freundlich adsorption isotherm equations. It was found that the overall process was mass transfer controlled and that the adsorption equilibrium could be described by a linear isotherm for the concentrations used in this study.

  12. Development of Superior Sorbents for Separation of CO2 from Flue Gas at a Wide Temperature Range During Coal Combustion

    SciTech Connect

    Panagiotis G. Smirniotis

    2007-06-30

    In chapter 1, the studies focused on the development of novel sorbents for reducing the carbon dioxide emissions at high temperatures. Our studies focused on cesium doped CaO sorbents with respect to other major flue gas compounds in a wide temperature range. The thermo-gravimetric analysis of sorbents with loadings of CaO doped on 20 wt% cesium demonstrated high CO{sub 2} sorption uptakes (up to 66 wt% CO{sub 2}/sorbent). It is remarkable to note that zero adsorption affinity for N{sub 2}, O{sub 2}, H{sub 2}O and NO at temperatures as high as 600 C was observed. For water vapor and nitrogen oxide we observed a positive effect for CO{sub 2} adsorption. In the presence of steam, the CO{sub 2} adsorption increased to the highest adsorption capacity of 77 wt% CO{sub 2}/sorbent. In the presence of nitrogen oxide, the final CO{sub 2} uptake remained same, but the rate of adsorption was higher at the initial stages (10%) than the case where no nitrogen oxide was fed. In chapter 2, Ca(NO{sub 3}){sub 2} {center_dot} 4H{sub 2}O, CaO, Ca(OH){sub 2}, CaCO{sub 3}, and Ca(CH{sub 3}COO){sub 2} {center_dot} H{sub 2}O were used as precursors for synthesis of CaO sorbents on this work. The sorbents prepared from calcium acetate (CaAc{sub 2}-CaO) resulted in the best uptake characteristics for CO{sub 2}. It possessed higher BET surface area and higher pore volume than the other sorbents. According to SEM images, this sorbent shows 'fluffy' structure, which probably contributes to its high surface area and pore volume. When temperatures were between 550 and 800 C, this sorbent could be carbonated almost completely. Moreover, the carbonation progressed dominantly at the initial short period. Under numerous adsorption-desorption cycles, the CaAc{sub 2}-CaO demonstrated the best reversibility, even under the existence of 10 vol % water vapor. In a 27 cyclic running, the sorbent sustained fairly high carbonation conversion of 62%. Pore size distributions indicate that their pore volume

  13. Destruction of problematic airborne contaminants by hydrogen reduction using a Catalytically Active, Regenerable Sorbent (CARS)

    NASA Technical Reports Server (NTRS)

    Thompson, John O.; Akse, James R.

    1993-01-01

    Thermally regenerable sorbent beds were demonstrated to be a highly efficient means for removal of toxic airborne trace organic contaminants aboard spacecraft. The utilization of the intrinsic weight savings available through this technology was not realized since many of the contaminants desorbed during thermal regeneration are poisons to the catalytic oxidizer or form highly toxic oxidation by-products in the Trace Contaminant Control System (TCCS). Included in this class of compounds are nitrogen, sulfur, silicon, and halogen containing organics. The catalytic reduction of these problematic contaminants using hydrogen at low temperatures (200-300 C) offers an attractive route for their destruction since the by-products of such reactions, hydrocarbons and inorganic gases, are easily removed by existing technology. In addition, the catalytic oxidizer can be operated more efficiently due to the absence of potential poisons, and any posttreatment beds can be reduced in size. The incorporation of the catalyst within the sorbent bed further improves the system's efficiency. The demonstration of this technology provides the basis for an efficient regenerable TCCS for future NASA missions and can be used in more conventional settings to efficiently remove environmental pollutants.

  14. Method of removing hydrogen sulfide from gases utilizing a zinc oxide sorbent and regenerating the sorbent

    DOEpatents

    Jalan, Vinod M.; Frost, David G.

    1984-01-01

    A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500.degree. C. to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent.

  15. Application of a sorbent trap system to gas-phase elemental and oxidized mercury analysis.

    PubMed

    Zhang, Zishuo; Eom, Yujin; Lee, Michelle J; Lee, Tai Gyu

    2016-07-01

    A sorbent trap that utilizes activated carbon (AC) as the solid trapping medium is a new technology for measuring total mercury (Hg) emissions from combustion facilities. In this study, sorbent trap technology was further developed, improved and evaluated at the laboratory scale. AC was impregnated with 5% aqua regia to enhance its Hg adsorption capacity. Sorbent traps spiked with an Hg standard solution were found to be reproducibly prepared and highly stable. The effect of the Hg concentration on the spiking efficiency was further investigated. The adsorption of elemental and oxidized Hg by the sorbent trap was studied under various experimental conditions (temperature, flow rate and inlet Hg concentration). The Hg concentration of the flue gas effluent from the sorbent trap was measured. In addition, the concentration of Hg adsorbed on the AC was determined by digesting the used AC with an acid according to US EPA method 3052 and then analyzing it with cold vapor atomic absorption spectrometry. Furthermore, the gas-phase Hg emissions from a combustion source were measured using the sorbent trap according to US EPA method 30B. The results showed that the sorbent trap could be used for Hg concentrations between 10.0 and 40.0 μg m(-3) and flow rates between 0.5 and 1.0 lpm with adsorption efficiencies greater than 90%.

  16. Dewatering Peat With Activated Carbon

    NASA Technical Reports Server (NTRS)

    Rohatgi, N. K.

    1984-01-01

    Proposed process produces enough gas and carbon to sustain itself. In proposed process peat slurry is dewatered to approximately 40 percent moisture content by mixing slurry with activated carbon and filtering with solid/liquid separation techniques.

  17. Characterization of active sites, determination of mechanisms of H(2)S, COS and CS(2) sorption and regeneration of ZnO low-temperature sorbents: past, current and perspectives.

    PubMed

    Samokhvalov, Alexander; Tatarchuk, Bruce J

    2011-02-28

    The intellectually and technically challenging pursuit of the emerging global environmentally "green" and energy-efficient infrastructure of the 21st century requires the development of a worldwide network of low- to medium-power fuel cell (FC) based portable electric power-generating devices and high-power biomass/clean coal "electric+chemical plants" with zero carbon footprint utilizing integrated coal gasification combined cycle with geologic carbon sequestration (IGCC-GCS) under energy-efficient low-temperature conditions. These emerging technologies require the deep and ultradeep desulfurization of gaseous feeds, since sulfur compounds, especially hydrogen sulfide H(2)S are highly corrosive and poisonous to both technological processes and the environment. Therefore, it is of crucial importance for both academic and industrial research communities to have a solid understanding of the atomic-level structures of active sites and molecular-level mechanisms of surface chemical reactions of the novel deep and ultradeep desulfurization materials, especially desulfurization sorbents. This review critically analyzes the recent literature (last ∼20 years) on the experimental determination of molecular and atomic-level nature of adsorption sites, effects of desulfurization promoters, mechanisms of chemical reactions of H(2)S, COS and CS(2) and physical processes during and upon regeneration of "spent" low-temperature H(2)S sorbents based on ZnO that were developed for desulfurization of fuel reformates, syngas and similar streams. Recent trends in research on the ultradeep H(2)S sorbents are discussed with an impetus on real-time in situ and Operando techniques of instrumental chemical analysis, and the challenges of direct determination of the structure of active sites and of the experimental mechanistic studies in general are described.

  18. A novel needle trap device with single wall carbon nanotubes sol-gel sorbent packed for sampling and analysis of volatile organohalogen compounds in air.

    PubMed

    Heidari, Mahmoud; Bahrami, Abdolrahman; Ghiasvand, Ali Reza; Shahna, Farshid Ghorbani; Soltanian, Ali Reza

    2012-11-15

    This paper describes a new approach that combines needle trap devices (NTDs) with a newly synthesized silanated nano material as sorbent for sampling and analysis of HVOCs in air. The sol-gel technique was used for preparation of the single wall carbon nanotube (SWCNT)/silica composite as sorbent, packed inside a 21-gauge NTD. Application of this method as an exhaustive sampler device was investigated under different laboratory conditions in this study. Predetermined concentrations of each analyte were prepared in a home-made standard chamber, and the effects of experimental parameters, such as temperature, humidity, sampling air flow rate, breakthrough volume and storage time on NTD, and the sorbent performance were investigated. The proposed NTD was used in two different modes and two different injection methods, and an NTD with a side hole, a narrow neck glass liner and syringe pump assisted injection of carrier gas were applied. The NTD packed with SWCNTs/silica composite was compared to the NTD packed with PDMS and also SPME with CAR/PDMS. For four compounds, LOD was 0.001-0.01 ng mL(-1), LOQ was 0.007-0.03 ng mL(-1), and the relative standard division for repeatability of method was 2.5-6.7%. The results show that the incorporation of NTD and SWCNTs/silica composite is a reliable and effective approach for the sampling and analysis of HVOCs in air. Coupling this system to GC-MS make it more sensitive and powerful technique.

  19. ADVANCED SORBENT DEVELOPMENT PROGRAM

    SciTech Connect

    Unknown

    1998-06-16

    The overall objective of this program was to develop regenerable sorbents for use in the temperature range of 343 to 538 C (650 to 1000 F) to remove hydrogen sulfide (H{sub 2}S) from coal-derived fuel gases in a fluidized-bed reactor. The goal was to develop sorbents that are capable of reducing the H{sub 2}S level in the fuel gas to less than 20 ppmv in the specified temperature range and pressures in the range of 1 to 20 atmospheres, with chemical characteristics that permit cyclic regeneration over many cycles without a drastic loss of activity, as well as physical characteristics that are compatible with the fluidized bed application.

  20. Metal chlorides loaded on activated carbon to capture elemental mercury.

    PubMed

    Shen, Zhemin; Ma, Jing; Mei, Zhijian; Zhang, Jianda

    2010-01-01

    Activated carbon (AC) was considered to be an effective sorbent to control mercury in combustion systems. However, its capture capacity was low and it required a high carbon-to-mercury mass ratio. AC loaded with catalyst showed a high elemental mercury (Hg0) capture capacity due to large surface area of AC and high oxidization ability of catalyst. In this study, several metal chlorides and metal oxides were used to promote the sorption capacity of AC. As a result, metal chlorides were better than metal oxides loaded on AC to remove gaseous mercury. X-ray diffractometer (XRD), thermogravimetric analyzer (TGA) and specific surface area by Brunauer-Emmett-Teller method (BET) analysis showed the main mechanisms: first, AC had an enormous surface area for loading enough MClx; second, Cl and MxOy were generated during pyrogenation of MClx; finally, there were lots of active elements such as Cl and MxOy which could react with elemental mercury and convert it to mercury oxide and mercury chloride. The HgO and HgCl2 might be released from AC's porous structure by thermo regeneration. A catalytic chemisorption mechanism predominates the sorption process of elemental mercury. As Co and Mn were valence variable metal elements, their catalytic effect on Hg0 oxidization may accelerate both oxidation and halogenation of Hg0. The sorbents loaded with metal chlorides possessed a synergistic function of catalytic effect of valence variable metal and chlorine oxidation.

  1. Cleanup of Savannah River Plant solvent using solid sorbents

    SciTech Connect

    Mailen, J.C.; Tallent, O.K.

    1985-04-01

    The degradation products produced in Purex solvent by exposure to nitric acid and radiation can be divided into two groups: those which are removed by scrubbing with sodium carbonate solutions and those which are not; these latter materials are called secondary degradation products. This study investigated the use of solid sorbents for removal of the secondary degradation products from first-cycle Savannah River Plant solvent that had been previously washed with sodium carbonate solution. Silica gel, activated charcoal, macroreticular resin, attapulgite clay and activated alumina were the sorbents investigated in preliminary testing. Activated alumina was found to be most effective for improving phase separation of the solvent from sodium carbonate solutions and for increasing the interfacial tension. The activated alumina was also the sorbent most useful for removing complexants which retain plutonium at low acidity, but it was less effective in removing anionic surfactants and ruthenium. We found that the capacity of the activated alumina was greatly improved by drying the solvent before treatment.

  2. Durable zinc ferrite sorbent pellets for hot coal gas desulfurization

    DOEpatents

    Jha, Mahesh C.; Blandon, Antonio E.; Hepworth, Malcolm T.

    1988-01-01

    Durable, porous sulfur sorbents useful in removing hydrogen sulfide from hot coal gas are prepared by water pelletizing a mixture of fine zinc oxide and fine iron oxide with inorganic and organic binders and small amounts of activators such as sodium carbonate and molybdenite; the pellets are dried and then indurated at a high temperature, e.g., 1800.degree. C., for a time sufficient to produce crush-resistant pellets.

  3. Microlith-based Structured Sorbent for Carbon Dioxide, Humidity, and Trace Contaminant Control in Manned Space Habitats

    NASA Technical Reports Server (NTRS)

    Junaedi, Christian; Roychoudhury, SUbir; Howard, David F.; Perry, Jay L.; Knox, James C.

    2011-01-01

    To support continued manned space exploration, the development of atmosphere revitalization systems that are lightweight, compact, durable, and power efficient is a key challenge. The systems should be adaptable for use in a variety of habitats and should offer operational functionality to either expel removed constituents or capture them for closedloop recovery. As mission durations increase and exploration goals reach beyond low earth orbit, the need for regenerable adsorption processes for continuous removal of CO2 and trace contaminants from cabin air becomes critical. Precision Combustion, Inc. (PCI) and NASA Marshall (MSFC) have been developing an Engineered Structured Sorbents (ESS) approach based on PCI s patented Microlith technology to meet the requirements of future, extended human spaceflight explorations. This technology offers the inherent performance and safety attributes of zeolite and other sorbents with greater structural integrity, regenerability, and process control, thereby providing potential durability and efficiency improvements over current state-of-the-art systems. The major advantages of the ESS explored in this study are realized through the use of metal substrates to provide structural integrity (i.e., less partition of sorbents) and enhanced thermal control during the sorption process. The Microlith technology also offers a unique internal resistive heating capability that shows potential for short regeneration time and reduced power requirement compared to conventional systems. This paper presents the design, development, and performance results of the integrated adsorber modules for removing CO2, water vapor, and trace chemical contaminants. A related effort that utilizes the adsorber modules for sorption of toxic industrial chemicals is also discussed. Finally, the development of a 4-person two-leg ESS system for continuous CO2 removal is also presented.

  4. High Temperature Sorbents for Oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor)

    1996-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C is introduced. The sorbent comprises a porous alumina silicate support such as zeolite containing from 1 to 10 percent by weight of ion exchanged transition metal such as copper or cobalt ions and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum. The activation temperature, oxygen sorption and reducibility are all improved by the presence of the platinum activator.

  5. Mercury Removal with Activated Carbon in Coal-Fired Power Plants

    NASA Astrophysics Data System (ADS)

    Rapperport, J.; Sasmaz, E.; Wilcox, J.

    2010-12-01

    Coal is both the most abundant and the dirtiest combustible energy source on earth. In the United States, about half of the country’s electricity comes from coal combustion and the industry is rapidly expanding all over the world. Among many of coal’s flaws, its combustion annually produces roughly 50 tones in the U.S. and 5000 tons worldwide of mercury, a carcinogen and highly toxic pollutant. Certain sorbents and processes are used to try to limit the amount of mercury that reaches the atmosphere, a key aspect of reducing the energy source’s harmful environmental impact. This experiment’s goal is to discover what process occurs on a sorbent surface during mercury’s capture while also determining sorbent effectiveness. Bench-scale experiments are difficult to carry out since the focus of the experiment is to simulate mercury capture in a power plant flue gas stream, where mercury is in its elemental form. The process involves injecting air, elemental mercury and other components to simulate a coal exhaust environment, and then running the stream through a packed-bed reactor with an in-tact sorbent. While carrying out the reactor tests, the gas-phase is monitored for changes in mercury oxidation and following these gas-phase studies, the mercury-laden sorbent is analyzed using x-ray photoelectron spectroscopy. Conclusions that can be drawn thus far are that brominated activated carbon shows very high mercury capture and that mercury is found in its oxidized form on the surface of the sorbent. The speciation, or conclusions drawn on the process and bonding sites on the surface, cannot be determined at this point simply using the current spectroscopic analysis.

  6. Metal Ion Removal from Wastewaters by Sorption on Activated Carbon, Cement Kiln Dust, and Sawdust.

    PubMed

    Shaheen, Sabry M; Eissa, Fawzy I; Ghanem, Khaled M; El-Din, Hala M Gamal; Al Anany, Fathia S

    2015-06-01

    This study assessed the efficiency of activated carbon, cement kiln dust (CKD), and sawdust for the removal of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) from aqueous solutions under mono-metal and competitive sorption systems and the removal of Cd, Cu, and Zn from different industrial wastewaters. Batch equilibrium experiments were conducted in a mono-metal and competitive sorption system. The efficiency of the sorbents in the removal of Cd, Cu, and Zn from industrial wastewaters was also investigated. Cement kiln dust expressed the highest affinity for the metals followed by activated carbon and sawdust. Competition among the metals changed their distribution coefficient (Kd) with the sorbents. Sorption of Pb and Cu was higher than Cd and Zn. The average metal removal from the wastewaters varied from 74, 61, and 60% for Cd, Cu, and Zn, respectively, to nearly 100%. The efficiencies of CKD and activated carbon in removing metals were higher than sawdust, suggesting their potential as low-cost sorbents for the removal of toxic metals from wastewaters.

  7. CO(2) adsorption on supported molecular amidine systems on activated carbon.

    PubMed

    Alesi, W Richard; Gray, McMahan; Kitchin, John R

    2010-08-23

    The CO(2) capture capacities for typical flue gas capture and regeneration conditions of two tertiary amidine N-methyltetrahydropyrimidine (MTHP) derivatives supported on activated carbon were determined through temperature-controlled packed-bed reactor experiments. Adsorption-desorption experiments were conducted at initial adsorption temperatures ranging from 29 degrees C to 50 degrees C with temperature-programmed regeneration under an inert purge stream. In addition to the capture capacity of each amine, the efficiencies at which the amidines interact with CO(2) were determined. Capture capacities were obtained for 1,5-diazo-bicyclo[4.3.0]non-5-ene (DBN) and 1,8-diazobicyclo[5.4.0]-undec-7-ene (DBU) supported on activated carbon at a loading of approximately 2.7 mol amidine per kg of sorbent. Moisture was found to be essential for CO(2) capture on the amidines, but parasitic moisture sorption on the activated carbon ultimately limited the capture capacities. DBN was shown to have a higher capture capacity of 0.8 mol CO(2) per kg of sorbent and an efficiency of 0.30 mol CO(2) per mol of amidine at an adsorption temperature of 29 degrees C compared to DBU. The results of these experiments were then used in conjunction with a single-site adsorption model to derive the Gibbs free energy for the capture reaction, which can provide information about the suitability of the sorbent under different operating conditions.

  8. Investigation on durability and reactivity of promising metal oxide sorbents during sulfidation and regeneration. Quarterly report, October--December 1994

    SciTech Connect

    Kwon, K.C.

    1995-01-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at high pressures and high temperatures. Metal oxides such as zinc titanate oxides, zinc ferrite oxide, copper oxide, manganese oxide and calcium oxide, were found to be promising sorbents in comparison with other removal methods such as membrane separations and reactive membrane separations. Some metal oxide sorbents exhibited the quite favorable performance in terms of attrition resistance and sulfur capacity. Removal reaction of H{sub 2}S from coal gas mixtures with ZT-4 or other promising sorbents of fine solid particles, and regeneration reaction of sulfur-loaded sorbents will be carried on in a batch reactor or a continuous differential reactor. The objectives of this research project are to find intrinsic initial reaction kinetics for the metal oxide-hydrogen sulfide heterogeneous reaction system, to obtain effects of concentrations of coal gas components such as hydrogen, carbon monoxide, carbon dioxide, oxygen, nitrogen and moisture on equilibrium reaction rate constants of the reaction system at various reaction temperatures and pressures, to identify regeneration kinetics of sulfur-loaded metal oxide sorbents, and to formulate promising metal oxide sorbent for the removal of sulfur from coal gas mixtures. Promising durable metal oxide sorbents of high-sulfur-absorbing capacity will be formulated by mixing active metal oxide powders with inert metal oxide powders and calcining these powder mixtures, or impregnating active metal oxide sorbents on supporting metal oxide matrixes.

  9. Investigation on durability and reactivity of promising metal oxide sorbents during sulfidation and regeneration. Quarterly report, January--March 1995

    SciTech Connect

    Kwon, K.C.

    1995-03-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at high pressures and high temperatures. Metal oxides such as zinc titanate oxides, zinc ferrite oxide, copper oxide, manganese oxide and calcium oxide, were found to be promising sorbents in comparison with other removal methods such as membrane separations and reactive membrane separations. Some metal oxide sorbents exhibited the quite favorable performance in terms of attrition resistance and sulfur capacity. Removal reaction of H{sub 2}S from coal gas mixtures with ZT-4 or other promising sorbents of fine solid particles, and regeneration reaction of sulfur-loaded sorbents will be carried on in a batch reactor or a continuous differential reactor. The objectives of this research project are to find intrinsic initial reaction kinetics for the metal oxide-hydrogen sulfide heterogeneous reaction system, to obtain effects of concentrations of coal gas components such as hydrogen, carbon monoxide, carbon dioxide, oxygen, nitrogen and moisture on equilibrium reaction rate constants of the reaction system at various reaction temperatures and pressures, to identify regeneration kinetics of sulfur-loaded metal oxide sorbents, and to formulate promising metal oxide sorbents for the removal of sulfur from coal gas mixtures. Promising durable metal oxide sorbents of high-sulfur-absorbing capacity will be formulated by mixing active metal oxide powders with inert metal oxide powders and calcining these powder mixtures, or impregnating active metal oxide sorbents on supporting metal oxide matrixes.

  10. Evaluation of sorbent materials

    SciTech Connect

    Rankin, W.N.; Gomillion, S.L.; Luckenbach, R.L.

    1989-01-01

    The sorption efficiency of different types of liquid sorbent materials was determined under carefully controlled laboratory conditions. Results show that the sorption capacity is affected both by the type of material and by the form of the material. Attractive alternate sorbents to ''atomic wipes'' and Oil-Dry were identified. Small pillows of shredded synthetic sorbents are an attractive alternative to Oil-Dry as a sorbent and to ''atomic wipes'' as both a sorbent and in decontamination by wiping. Synthetic sorbents in cloth form offer an attractive alternative to ''atomic wipes'' in decontamination by wiping because these materials are compatible with nitric acid and they may be more fire resistant. A larger-scale evaluation is planned with the most promising sorbents. In addition, development is planned of a sorbent that will be efficient, compatible with nitric acid and fire resistant. 6 refs., 2 tabs.

  11. Evaluation of sorbent materials

    SciTech Connect

    Rankin, W N; Gomillion, S L; Luckenbach, R L

    1989-01-01

    The sorption efficiency of different types of liquid sorbent materials was determined under carefully controlled laboratory conditions. Results show that the sorption capacity is affected both by the type of material and by the form of the material. Attractive alternate sorbents to atomic wipes'' and Oil-Dry were identified. Small pillows of shredded synthetic sorbents are an attractive alternative to Oil-Dry as a sorbent and to atomic wipes'' as both a sorbent and in decontamination by wiping. Synthetic sorbents in cloth form offer an attractive alternative to atomic wipes'' in decontamination by wiping because theses materials are compatible with nitric acid and they may be more fire resistant. A larger-scale evaluation is planned with the most promising sorbents. In addition, development is planned of a sorbent that will be efficient, compatible with nitric acid, fire resistant. 6 refs., 2 tabs.

  12. Moving-bed sorbents

    SciTech Connect

    Ayala, R.E.; Gupta, R.P.; Chuck, T.

    1995-12-01

    The objective of this program is to develop mixed-metal oxide sorbent formulations that are suitable for moving-bed, high-temperature, desulfurization of coal gas. Work continues on zinc titanates formulations and Z-sorb III sorbent.

  13. Collection of fission and activation product elements from fresh and ocean waters: a comparison of traditional and novel sorbents

    SciTech Connect

    Johnson, Bryce E.; Santschi, Peter H.; Addleman, Raymond S.; Douglas, Matthew; Davidson, Joseph D.; Fryxell, Glen E.; Schwantes, Jon M.

    2010-04-01

    Monitoring natural waters for the inadvertent release of radioactive fission products produced as a result of nuclear power generation downstream from these facilities is essential for maintaining water quality. To this end, we evaluated sorbents for simultaneous in-situ large volume extraction of radionuclides with both soft (e.g., Ag) and hard metal (e.g., Co, Zr, Nb, Ba, and Cs) or anionic (e.g., Ru, Te, Sb) character. In this study, we evaluated a number of conventional and novel nanoporous sorbents in both fresh and salt waters. In most cases, the nanoporous sorbents demonstrated enhanced retention of analytes. Salinity had significant effects upon sorbent performance and was most significant for hard cations, specifically Cs and Ba. The presence of natural organic matter had little effect on the ability of chemisorbents to extract target elements.

  14. Removal of alkali vapors by a fixed granular-bed sorber using activated bauxite as a sorbent

    SciTech Connect

    Lee, S.H.D.; Henry, R.F.; Myles, K.M.

    1985-03-01

    Studies have been conducted to develop a fixed granular-bed sorber for the removal of alkali vapors in a pressurized fluidized-bed combustion (PFBC) combinedcycle system. A laboratory-scale pressurized alkalivapor sorption test unit was used to characterize activated bauxite, the most effective sorbent identified earlier, for its alkali vapor sorption capability in a gas stream with temperature (less than or equal to900/sup 0/C), pressure (10 atm absolute), and composition closely simulating the actual PFBC flue gas. A scale-up of laboratory tests is being conducted in a 15.2-cm-dia (6-in.-dia) PFBC system to demonstrate the granular-bed sorber concept. The NaCl-vapor sorption chemistry of activated bauxite is described. The extent of alkalivapor evolution from the activated bauxite bed itself is discussed, along with an evaluation of the significance of its alkali vapor contribution to a downstream gas turbine. Details of the design of a high-temperature/high-pressure alkali sorber system for the demonstration of the sorber are presented.

  15. Removal of alkali vapors by a fixed granular-bed sorber using activated bauxite as a sorbent

    SciTech Connect

    Lee, S.H.D.; Henry, R.F.; Myles, K.M.

    1985-01-01

    Studies have been conducted to develop a fixed granular-bed sorber for the removal of alkali vapors in a pressurized fluidized-bed combustion (PFBC) combined-cycle system. A laboratory-scale pressurized alkali vapor sorption test unit was used to characterize activated bauxite, the most effective sorbent identified earlier, for its alkali vapor sorption capability in a gas stream with temperature (less than or equal to 900/sup 0/C), pressure (10 atm absolute), and composition closely simulating the actual PFBC flue gas. A scale-up of laboratory tests is being conducted in a 15.2-cm-dia (6-in.-dia) PFBC system to demonstrate the granular-bed sorber concept. The NaCl-vapor sorption chemistry of activated bauxite is described. The extent of alkali-vapor evolution from the activated bauxite bed itself is discussed, along with an evaluation of the significance of its alkali vapor contribution to a downstream gas turbine. Details of the design of a high-temperature/high-pressure alkali sorber system for the demonstration of the sorber are presented. 15 references, 6 figures, 3 tables.

  16. Sol-gel derived sorbents

    DOEpatents

    Sigman, Michael E.; Dindal, Amy B.

    2003-11-11

    Described is a method for producing copolymerized sol-gel derived sorbent particles for the production of copolymerized sol-gel derived sorbent material. The method for producing copolymerized sol-gel derived sorbent particles comprises adding a basic solution to an aqueous metal alkoxide mixture for a pH.ltoreq.8 to hydrolyze the metal alkoxides. Then, allowing the mixture to react at room temperature for a precalculated period of time for the mixture to undergo an increased in viscosity to obtain a desired pore size and surface area. The copolymerized mixture is then added to an immiscible, nonpolar solvent that has been heated to a sufficient temperature wherein the copolymerized mixture forms a solid upon the addition. The solid is recovered from the mixture, and is ready for use in an active sampling trap or activated for use in a passive sampling trap.

  17. Lime-based sorbents for high-temperature CO2 capture--a review of sorbent modification methods.

    PubMed

    Manovic, Vasilije; Anthony, Edward J

    2010-08-01

    This paper presents a review of the research on CO(2) capture by lime-based looping cycles undertaken at CanmetENERGY's (Ottawa, Canada) research laboratories. This is a new and very promising technology that may help in mitigation of global warming and climate change caused primarily by the use of fossil fuels. The intensity of the anticipated changes urgently requires solutions such as more cost-effective technologies for CO(2) capture. This new technology is based on the use of lime-based sorbents in a dual fluidized bed combustion (FBC) reactor which contains a carbonator-a unit for CO(2) capture, and a calciner-a unit for CaO regeneration. However, even though natural materials are cheap and abundant and very good candidates as solid CO(2) carriers, their performance in a practical system still shows significant limitations. These limitations include rapid loss of activity during the capture cycles, which is a result of sintering, attrition, and consequent elutriation from FBC reactors. Therefore, research on sorbent performance is critical and this paper reviews some of the promising ways to overcome these shortcomings. It is shown that reactivation by steam/water, thermal pre-treatment, and doping simultaneously with sorbent reforming and pelletization are promising potential solutions to reduce the loss of activity of these sorbents over multiple cycles of use.

  18. Sorption of methylxanthines by different sorbents

    NASA Astrophysics Data System (ADS)

    Dmitrienko, S. G.; Andreeva, E. Yu.; Tolmacheva, V. V.; Terent'eva, E. A.

    2013-05-01

    Sorption of caffeine, theophylline, theobromine, diprophylline, and pentoxyphylline on different sorbents (supercross-linked polystyrene, surface-modified copolymer of styrene and divinylbenzene Strata-X, and carbon nanomaterials Taunit and Diasorb-100-C16T) was studied in a static mode in an effort to find new sorbents suitable for sorption isolation and concentration of methylxanthines. The peculiarities of sorption of methylxanthines were explained in relation to the solution acidity, the nature of the sorbates and their concentration, the nature of the solvent, and the structural characteristics of the sorbents.

  19. Separating proteins with activated carbon.

    PubMed

    Stone, Matthew T; Kozlov, Mikhail

    2014-07-15

    Activated carbon is applied to separate proteins based on differences in their size and effective charge. Three guidelines are suggested for the efficient separation of proteins with activated carbon. (1) Activated carbon can be used to efficiently remove smaller proteinaceous impurities from larger proteins. (2) Smaller proteinaceous impurities are most efficiently removed at a solution pH close to the impurity's isoelectric point, where they have a minimal effective charge. (3) The most efficient recovery of a small protein from activated carbon occurs at a solution pH further away from the protein's isoelectric point, where it is strongly charged. Studies measuring the binding capacities of individual polymers and proteins were used to develop these three guidelines, and they were then applied to the separation of several different protein mixtures. The ability of activated carbon to separate proteins was demonstrated to be broadly applicable with three different types of activated carbon by both static treatment and by flowing through a packed column of activated carbon.

  20. Water Utility Lime Sludge Reuse – An Environmental Sorbent for Power Utilities

    EPA Science Inventory

    Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up ...

  1. Alkali metal vapor removal from pressurized fluidized-bed combustor flue gas: activated bauxite sorbent regeneration. Quarterly report, October-December 1980

    SciTech Connect

    Johnson, I.; Lee, S.H.D.

    1981-05-01

    This work supports the program to develop methods for the cleanup of combustion gases from pressurized fluidized-bed coal combustors so that the cleaned gases can be used to power downstream gas turbines. Presented here are the results of studies to develop granular sorbents for removing gaseous alkali metal compounds from these combustion gases in a granular-bed filter. Activated bauxite bed material can be reused after the alkali compound is removed by a water-leaching process. In experiments to study the kinetics of leaching, the effects of adsorbed NaCl loading, leaching temperature, and the leaching water to sorbent ratio on the rate of leaching are reported. Also reported are water retention in bauxite after leaching and the effect of volatile alkalis in makeup activated bauxite on the alkali level in flue gas expanded in the gas turbine.

  2. Fluidized-bed sorbents

    SciTech Connect

    Gangwal, S.K.; Gupta, R.P.

    1994-10-01

    The objectives of this project are to identify and demonstrate methods for enhancing long-term chemical reactivity and attrition resistance of zinc oxide-based mixed metal-oxide sorbents for desulfurization of hot coal-derived gases in a high-temperature, high-pressure (HTHP) fluidized-bed reactor. In this program, regenerable ZnO-based mixed metal-oxide sorbents are being developed and tested. These include zinc ferrite, zinc titanate, and Z-SORB sorbents. The Z-SORB sorbent is a proprietary sorbent developed by Phillips Petroleum Company (PPCo).

  3. Application of engineered sorbent barriers Summary of Laboratory Data for FY 1988

    SciTech Connect

    Freeman, H.D.; Jones, E.O.

    1989-09-01

    Laboratory studies were conducted in FY 1988 Pacific Northwest Laboratory to determine the effect of contact time, pH, solution to solid ratio, and particle size on the performance of a number of materials in adsorbing radioactive cobalt, strontium, and cesium. The laboratory studies were conducted to provide background information useful in designing an engineered sorbent barrier, which restricts the migration of radionuclides from low-level waste sites. Understanding how the variables affect the adsorption of ions on the sorbent materials is the key to estimating the performance of sorbent barriers under a variety of conditions. The scope of the studies was limited to three radionuclides and four sorbent materials, but the general approach can be used to evaluate other radionuclides and conditions. The sorbent materials evaluated in this study included clinoptilolite, activated carbon, bentonite clay, and Savannah River soil. The clinoptilolite and activated carbon were identified in previous studies as the most cost-effective materials for sorption of the three radionuclides under consideration. The bentonite clay was evaluated as a component of the barrier that could be used to modify the permeability of the barrier system. The Savannah River soil was used to represent soil from a humid site. 3 refs., 14 figs., 1 tab.

  4. Studies on adsorption of mercury from aqueous solution on activated carbons prepared from walnut shell.

    PubMed

    Zabihi, M; Haghighi Asl, A; Ahmadpour, A

    2010-02-15

    The adsorption ability of a powdered activated carbons (PAC) derived from walnut shell was investigated in an attempt to produce more economic and effective sorbents for the control of Hg(II) ion from industrial liquid streams. Carbonaceous sorbents derived from local walnut shell, were prepared by chemical activation methods using ZnCl(2) as activating reagents. Adsorption of Hg(II) from aqueous solutions was carried out under different experimental conditions by varying treatment time, metal ion concentration, pH and solution temperature. It was shown that Hg(II) uptake decreases with increasing pH of the solution. The proper choice of preparation conditions were resulted in microporous activated carbons with different BET surface areas of 780 (Carbon A, 1:0.5 ZnCl(2)) and 803 (Carbon B, 1:1 ZnCl(2))m(2)/g BET surface area. The monolayer adsorption capacity of these particular adsorbents were obtained as 151.5 and 100.9 mg/g for carbons A and B, respectively. It was determined that Hg(II) adsorption follows both Langmuir and Freundlich isotherms as well as pseudo-second-order kinetics.

  5. A new method for the rapid determination of volatile organic compound breakthrough times for a sorbent at concentrations relevant to indoor air quality.

    PubMed

    Scahill, John; Wolfrum, Edward J; Michener, William E; Bergmann, Michael; Blake, Daniel M; Watt, Andrew S

    2004-01-01

    The use of sorbents has been proposed to remove volatile organic compounds (VOCs) present in ambient air at concentrations in the parts-per-billion (ppb) range, which is typical of indoor air quality applications. Sorbent materials, such as granular activated carbon and molecular sieves, are used to remove VOCs from gas streams in industrial applications, where VOC concentrations are typically in the parts-per-million range. A method for evaluating the VOC removal performance of sorbent materials using toluene concentrations in the ppb range is described. Breakthrough times for toluene at concentrations from 2 to 7500 ppb are presented for a hydrophobic molecular sieve at 25%) relative humidity. By increasing the ratio of challenge gas flow rate to the mass of the sorbent bed and decreasing both the mass of sorbent in the bed and the sorbent particle size, this method reduces the required experimental times by a factor of up to several hundred compared with the proposed American Society of Heating, Refrigerating, and Air-Conditioning Engineers method, ASHRAE 145P, making sorbent performance evaluation for ppb-range VOC removal more convenient. The method can be applied to screen sorbent materials for application in the removal of VOCs from indoor air.

  6. Biological activation of carbon filters.

    PubMed

    Seredyńska-Sobecka, Bozena; Tomaszewska, Maria; Janus, Magdalena; Morawski, Antoni W

    2006-01-01

    To prepare biological activated carbon (BAC), raw surface water was circulated through granular activated carbon (GAC) beds. Biological activity of carbon filters was initiated after about 6 months of filter operation and was confirmed by two methods: measurement of the amount of biomass attached to the carbon and by the fluorescein diacetate (FDA) test. The effect of carbon pre-washing on WG-12 carbon properties was also studied. For this purpose, the nitrogen adsorption isotherms at 77K and Fourier transform-infrared (FT-IR) spectra analyses were performed. Moreover, iodine number, decolorizing power and adsorption properties of carbon in relation to phenol were studied. Analysis of the results revealed that after WG-12 carbon pre-washing its BET surface increased a little, the pH value of the carbon water extract decreased from 11.0 to 9.4, decolorizing power remained at the same level, and the iodine number and phenol adsorption rate increased. In preliminary studies of the ozonation-biofiltration process, a model phenol solution with concentration of approximately 10mg/l was applied. During the ozonation process a dose of 1.64 mg O(3)/mg TOC (total organic carbon) was employed and the contact time was 5 min. Four empty bed contact times (EBCTs) in the range of 2.4-24.0 min were used in the biofiltration experiment. The effectiveness of purification was measured by the following parameters: chemical oxygen demand (COD(Mn)), TOC, phenol concentration and UV(254)-absorbance. The parameters were found to decrease with EBCT.

  7. Comparison of Impurities in Charcoal Sorbents Found by Neutron Activation Analysis

    SciTech Connect

    Doll, Charles G.; Finn, Erin C.; Cantaloub, Michael G.; Greenwood, Lawrence R.; Kephart, Jeremy; Kephart, Rosara F.

    2013-01-01

    Abstract: Neutron activation of gas samples in a reactor often requires a medium to retain sufficient amounts of the gas for analysis. Charcoal is commonly used to adsorb gas and hold it for activation; however, the amount of activated sodium in the charcoal after irradiation swamps most signals of interest. Neutron activation analysis (NAA) was performed on several commonly available charcoal samples in an effort to determine the activation background. The results for several elements, including the dominant sodium element, are reported. It was found that ECN charcoal had the lowest elemental background, containing sodium at 2.65 ± 0.05 ppm, as well as trace levels of copper and tungsten.

  8. Development of a Rapid Cycling CO2 and H2O Removal Sorbent

    NASA Technical Reports Server (NTRS)

    Alptekin, Gokhan; Cates, Matthew; Bernal, Casey; Dubovik, Margarita; Paul, Heather L.

    2007-01-01

    The National Aeronautics and Space Administration (NASA) planned future missions set stringent demands on the design of the Portable Life Support System (PLSS), requiring dramatic reductions in weight, decreased reliance on supplies and greater flexibility on the types of missions. Use of regenerable systems that reduce weight and volume of the Extravehicular Mobility Unit (EMU) is of critical importance to NASA, both for low orbit operations and for long duration manned missions. The carbon dioxide and humidity control unit in the existing PLSS design is relatively large, since it has to remove and store eight hours worth of carbon dioxide (CO2). If the sorbent regeneration can be carried out during the Extravehicular Activity (EVA) with a relatively high regeneration frequency, the size of the sorbent canister and weight can be significantly reduced. TDA Research, Inc. is developing compact, regenerable sorbent materials to control CO2 and humidity in the space suit ventilation loop. The sorbent can be regenerated using space vacuum during the EVA, eliminating all CO2 and humidity duration-limiting elements in the life support system. The material also has applications in other areas of space exploration including long duration exploration missions requiring regenerable technologies and possibly the Crew Exploration Vehicle (CEV) spacecraft. This paper summarizes the results of the sorbent development, testing, and evaluation efforts to date.

  9. Sorption of triclosan onto activated carbon, kaolinite and montmorillonite: effects of pH, ionic strength, and humic acid.

    PubMed

    Behera, Shishir Kumar; Oh, Seok-Young; Park, Hung-Suck

    2010-07-15

    Sorption of triclosan on three sorbents, viz., activated carbon, kaolinite and montmorillonite was studied as a function of pH, ionic strength and humic acid (HA) concentration through controlled batch experiments. Triclosan sorption was found to be higher in the acidic pH range, as varying pH showed significant influence on the surface charge of the sorbents and degree of ionization of the sorbate. Sorption capacity of the sorbents increased with an increase in the ionic strength of solution. At low pH (pH 3), the overall increase in triclosan sorption was 1.2, approximately 4 and 3.5 times, respectively for activated carbon, kaolinite and montmorillonite when ionic strength was increased from 1x10(-3) to 5x10(-1) M. Triclosan sorption onto activated carbon decreased from 31.4 to 10.6 mg g(-1) by increasing the HA concentration to 200 mg C L(-1). However, during sorption onto kaolinite and montmorillonite, the effect of HA was very complex probably due to (i) hydrophobicity (log K(ow)=4.76) of triclosan; and (ii) complexation of HA with triclosan. Though triclosan sorption onto activated carbon is higher, the potential of kaolinite and montmorillonite in controlling the transport of triclosan in subsurface environment can still be appreciable.

  10. Asphalt-derived high surface area activated porous carbons for carbon dioxide capture.

    PubMed

    Jalilov, Almaz S; Ruan, Gedeng; Hwang, Chih-Chau; Schipper, Desmond E; Tour, Josiah J; Li, Yilun; Fei, Huilong; Samuel, Errol L G; Tour, James M

    2015-01-21

    Research activity toward the development of new sorbents for carbon dioxide (CO2) capture have been increasing quickly. Despite the variety of existing materials with high surface areas and high CO2 uptake performances, the cost of the materials remains a dominant factor in slowing their industrial applications. Here we report preparation and CO2 uptake performance of microporous carbon materials synthesized from asphalt, a very inexpensive carbon source. Carbonization of asphalt with potassium hydroxide (KOH) at high temperatures (>600 °C) yields porous carbon materials (A-PC) with high surface areas of up to 2780 m(2) g(-1) and high CO2 uptake performance of 21 mmol g(-1) or 93 wt % at 30 bar and 25 °C. Furthermore, nitrogen doping and reduction with hydrogen yields active N-doped materials (A-NPC and A-rNPC) containing up to 9.3% nitrogen, making them nucleophilic porous carbons with further increase in the Brunauer-Emmett-Teller (BET) surface areas up to 2860 m(2) g(-1) for A-NPC and CO2 uptake to 26 mmol g(-1) or 114 wt % at 30 bar and 25 °C for A-rNPC. This is the highest reported CO2 uptake among the family of the activated porous carbonaceous materials. Thus, the porous carbon materials from asphalt have excellent properties for reversibly capturing CO2 at the well-head during the extraction of natural gas, a naturally occurring high pressure source of CO2. Through a pressure swing sorption process, when the asphalt-derived material is returned to 1 bar, the CO2 is released, thereby rendering a reversible capture medium that is highly efficient yet very inexpensive.

  11. Development of a Steel-Slag-Based, Iron-Functionalized Sorbent for an Autothermal Carbon Dioxide Capture Process.

    PubMed

    Tian, Sicong; Jiang, Jianguo; Hosseini, Davood; Kierzkowska, Agnieszka M; Imtiaz, Qasim; Broda, Marcin; Müller, Christoph R

    2015-11-01

    We propose a new class of autothermal CO2 -capture process that relies on the integration of chemical looping combustion (CLC) into calcium looping (CaL). In the new process, the heat released during the oxidation of a reduced metallic oxide is utilized to drive the endothermic calcination of CaCO3 (the regeneration step in CaL). Such a process is potentially very attractive (both economically and technically) as it can be applied to a variety of oxygen carriers and CaO is not in direct contact with coal (and the impurities associated with it) in the calciner (regeneration step). To demonstrate the practical feasibility of the process, we developed a low-cost, steel-slag-based, Fe-functionalized CO2 sorbent. Using this material, we confirm experimentally the feasibility to heat-integrate CaCO3 calcination with a Fe(II)/Fe(III) redox cycle (with regards to the heat of reaction and kinetics). The autothermal calcination of CaCO3 could be achieved for a material that contained a Ca/Fe ratio of 5:4. The uniform distribution of Ca and Fe in a solid matrix provides excellent heat transfer characteristics. The cyclic CO2 uptake and redox stability of the material is good, but there is room for further improvement.

  12. Activated carbon to the rescue

    SciTech Connect

    Sen, S.

    1996-03-01

    This article describes the response to pipeline spill of ethylene dichloride (EDC) on the property of an oil company. Activated carbon cleanup proceedure was used. During delivery, changeout, transport, storage, thermal reactivation, and return delivery to the site, the carbon never came into direct contact with operating personnel or the atmosphere. More than 10,000 tones of dredge soil and 50 million gallons of surface water were processed during the emergency response.

  13. Observations of limited secondary effects to benthic invertebrates and macrophytes with activated carbon amendment in river sediments.

    PubMed

    Beckingham, Barbara; Buys, David; Vandewalker, Heather; Ghosh, Upal

    2013-07-01

    Amendment of activated carbon to sediments has been shown to effectively reduce the bioavailability of hydrophobic organic contaminants, but concerns have been raised about the potential toxicological impacts of administering a strong sorbent into sediments. The present study provides a summary of several investigations carried out as part of a pilot-scale study in a river to understand the secondary effects of activated carbon added to reduce the bioavailability of sediment-associated polychlorinated biphenyls. While some previous laboratory amendment studies have found reduced lipid content in freshwater worms exposed to activated carbon-treated sediments, the authors did not observe an impact with fine-granular activated carbon-amended sediments aged in the field. Benthic community studies did not find differences between control and activated carbon-treated field sites over 3 yr of postapplication monitoring. Laboratory studies with submerged aquatic plants indicated reduced growth in sediments amended with ≥5% activated carbon, which was attributed to volume dilution of nutritional sediment or bulk density changes and was also observed when the sediment was amended with biochar and inert perlite. Since in situ sorbent amendment is likely to be implemented in depositional sediment environments, potential negative impacts will likely be short-term if the treated site is slowly covered with new sediment over time. Overall suitability of activated carbon amendment for a site will depend on balancing ecosystem and human health benefits from contaminant bioavailability reduction with any potential negative impacts expected under field conditions.

  14. Production of activated carbons from waste tyres for low temperature NOx control.

    PubMed

    Al-Rahbi, Amal S; Williams, Paul T

    2016-03-01

    Waste tyres were pyrolysed in a bench scale reactor and the product chars were chemically activated with alkali chemical agents, KOH, K2CO3, NaOH and Na2CO3 to produce waste tyre derived activated carbons. The activated carbon products were then examined in terms of their ability to adsorb NOx (NO) at low temperature (25°C) from a simulated industrial process flue gas. This study investigates the influence of surface area and porosity of the carbons produced with the different alkali chemical activating agents on NO capture from the simulated flue gas. The influence of varying the chemical activation conditions on the porous texture and corresponding NO removal from the flue gas was studied. The activated carbon sorbents were characterized in relation to BET surface area, micropore and mesopore volumes and chemical composition. The highest NO removal efficiency for the waste tyre derived activated carbons was ∼75% which was obtained with the adsorbent treated with KOH which correlated with both the highest BET surface area and largest micropore volume. In contrast, the waste tyre derived activated carbons prepared using K2CO3, NaOH and Na2CO3 alkali activating agents appeared to have little influence on NO removal from the flue gases. The results suggest problematic waste tyres, have the potential to be converted to activated carbons with NOx removal efficiency comparable with conventionally produced carbons.

  15. Evaluation of Solid Sorbents as a Retrofit Technology for CO2 Capture

    SciTech Connect

    Sjostrom, Sharon

    2016-06-02

    ADA completed a DOE-sponsored program titled Evaluation of Solid Sorbents as a Retrofit Technology for CO2 Capture under program DE-FE0004343. During this program, sorbents were analyzed for use in a post-combustion CO2 capture process. A supported amine sorbent was selected based upon superior performance to adsorb a greater amount of CO2 than the activated carbon sorbents tested. When the most ideal sorbent at the time was selected, it was characterized and used to create a preliminary techno-economic analysis (TEA). A preliminary 550 MW coal-fired power plant using Illinois #6 bituminous coal was designed with a solid sorbent CO2 capture system using the selected supported amine sorbent to both facilitate the TEA and to create the necessary framework to scale down the design to a 1 MWe equivalent slipstream pilot facility. The preliminary techno-economic analysis showed promising results and potential for improved performance for CO2 capture compared to conventional MEA systems. As a result, a 1 MWe equivalent solid sorbent system was designed, constructed, and then installed at a coal-fired power plant in Alabama. The pilot was designed to capture 90% of the CO2 from the incoming flue gas at 1 MWe net electrical generating equivalent. Testing was not possible at the design conditions due to changes in sorbent handling characteristics at post-regenerator temperatures that were not properly incorporated into the pilot design. Thus, severe pluggage occurred at nominally 60% of the design sorbent circulation rate with heated sorbent, although no handling issues were noted when the system was operated prior to bringing the regenerator to operating temperature. Testing within the constraints of the pilot plant resulted in 90% capture of the incoming CO2 at a flow rate equivalent of 0.2 to 0.25 MWe net electrical generating equivalent. The reduction in equivalent flow rate at 90% capture was

  16. High temperature hydrogen sulfide adsorption on activated carbon - I. Effects of gas composition and metal addition

    USGS Publications Warehouse

    Cal, M.P.; Strickler, B.W.; Lizzio, A.A.

    2000-01-01

    Various types of activated carbon sorbents were evaluated for their ability to remove H2S from a simulated coal gas stream at a temperature of 550 ??C. The ability of activated carbon to remove H2S at elevated temperature was examined as a function of carbon surface chemistry (oxidation, thermal desorption, and metal addition), and gas composition. A sorbent prepared by steam activation, HNO3 oxidation and impregnated with Zn, and tested in a gas stream containing 0.5% H2S, 50% CO2 and 49.5% N2, had the greatest H2S adsorption capacity. Addition of H2, CO, and H2O to the inlet gas stream reduced H2S breakthrough time and H2S adsorption capacity. A Zn impregnated activated carbon, when tested using a simulated coal gas containing 0.5% H2S, 49.5% N2, 13% H2, 8.5% H2O, 21% CO, and 7.5% CO2, had a breakthrough time of 75 min, which was less than 25 percent of the length of breakthrough for screening experiments performed with a simplified gas mixture of 0.5% H2S, 50% CO2, and 49.5% N2.

  17. Remediation of organochlorine pesticides contaminated lake sediment using activated carbon and carbon nanotubes.

    PubMed

    Hua, Shan; Gong, Ji-Lai; Zeng, Guang-Ming; Yao, Fu-Bing; Guo, Min; Ou, Xiao-Ming

    2017-06-01

    Organochlorine pesticides (OCPs) in sediment were a potential damage for humans and ecosystems. The aim of this work was to determine the effectiveness of carbon materials remedy hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethanes (DDTs) in sediment. Two different carbon materials including activated carbon (AC) and multi-walled carbon nanotubes (MWCNTs) were used in the present research. Sediment treated with 2 wt% AC and MWCNTs after 150 d contact showed 97%, and 75% reduction for HCH, and 93% and 59% decrease for DDTs in aqueous equilibrium concentration, respectively. Similarly, the reduction efficiencies of DDT and HCH uptake by semipermeable membrane devices (SPMDs) treated with AC (MWCNTs) were 97% (75%) and 92% (63%), respectively under the identical conditions. Furthermore, for 2 wt% AC (MWCNTs) system, a reduction of XAD beads uptake up to 87% (52%) and 73% (67%) was obtained in HCH and DDT flux to overlying water in quiescent system. Adding MWCNTs to contaminated sediment did not significantly decrease aqueous equilibrium concentration and DDTs and HCH availability in SPMDs compared to AC treatment. A series of results indicated that AC had significantly higher remediation efficiency towards HCH and DDTs in sediment than MWCNTs. Additionally, the removal efficiencies of two organic pollutants improved with increasing material doses and contact times. The greater effectiveness of AC was attributed to its greater specific surface area, which was favorable for binding contaminants. These results highlighted the potential for using AC as in-situ sorbent amendments for sediment remediation.

  18. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Jha, M.C.; Baltich, L.K.

    1987-02-23

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  19. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Silaban, A.; Harrison, D.P. . Dept. of Chemical Engineering)

    1989-05-02

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  20. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Jha, M.C.; Berggren, M.H.

    1989-05-02

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  1. Multiwalled carbon nanotubes as a sorbent material for the solid phase extraction of lead from urine and subsequent determination by electrothermal atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Peña Crecente, Rosa M.; Lovera, Carlha Gutiérrez; García, Julia Barciela; Méndez, Jennifer Álvarez; Martín, Sagrario García; Latorre, Carlos Herrero

    2014-11-01

    The determination of lead in urine is a way of monitoring the chemical exposure to this metal. In the present paper, a new method for the Pb determination by electrothermal atomic absorption spectrometry (ETAAS) in urine at low levels has been developed. Lead was separated from the undesirable urine matrix by means of a solid phase extraction (SPE) procedure. Oxidized multiwalled carbon nanotubes have been used as a sorbent material. Lead from urine was retained at pH 4.0 and was quantitatively eluted using a 0.7 M nitric acid solution and was subsequently measured by ETAAS. The effects of parameters that influence the adsorption-elution process (such as pH, eluent volume and concentration, sampling and elution flow rates) and the atomic spectrometry conditions have been studied by means of different factorial design strategies. Under the optimized conditions, the detection and quantification limits obtained were 0.08 and 0.26 μg Pb L- 1, respectively. The results demonstrate the absence of a urine matrix effect and this is the consequence of the SPE process carried out. Therefore, the developed method is useful for the analysis of Pb at low levels in real samples without the influence of other urine components. The proposed method was applied to the determination of lead in urine samples of unexposed healthy people and satisfactory results were obtained (in the range 3.64-22.9 μg Pb L- 1).

  2. Evaluation of a new carbon/zirconia-based sorbent for the cleanup of food extracts in multiclass analysis of pesticides and environmental contaminants.

    PubMed

    Han, Lijun; Sapozhnikova, Yelena; Matarrita, Jessie

    2016-12-01

    A novel carbon/zirconia-based material, Supel(TM) QuE Verde, was evaluated in a filter-vial dispersive solid-phase extraction cleanup of pork, salmon, kale, and avocado extracts for the residual analysis of 65 pesticides and 52 environmental contaminants (flame retardants, polychlorinated biphenyls, polybrominated diphenyl ethers, and polycyclic aromatic hydrocarbons) using low-pressure gas chromatography with tandem mass spectrometry. An amount of 180 mg sorbent per 0.6 mL extract in filter-vial dispersive solid-phase extraction cleanup was found the optimum in terms of achieving satisfactory removal of co-extractives and recoveries of analytes, especially for structurally planar compounds. For analytes partially retained by Verde, normalization to an internal standard resulted in 62-107% recoveries. Addition of Verde to primary secondary amine and C18 in cleanup resulted in 38% more removal of gas-chromatography-amenable co-extractives in avocado, 30% in kale, 39% in salmon, and 50% in pork. The removal efficiency of co-extracted chlorophyll was 93% for kale and 64% for avocado based on ultraviolet-visible absorbance. The developed method was validated at three spiking levels (10, 25, and 100 ng/g), and 70-120% recoveries with ≤20% relative standard deviation were achieved for 96 (83%) out of 117 analytes in pork, 79 (69%) in salmon, 71 (62%) in kale, and 75 (65%) in avocado.

  3. Trace contaminant adsorption and sorbent regeneration in closed ecological systems

    NASA Technical Reports Server (NTRS)

    Arnold, C. R.; Kersels, G. J.; Merrill, R. P.; Robell, A. J.; Wheeler, A.

    1972-01-01

    Correlation was obtained for determining sorptive capacity of carbon for pure and mixed contaminants under dry and humid conditions at various temperatures. Vacuum desorption rates were investigated for single particles and for sorbent beds. For sorbent beds, rate-determining step is Knudsen diffusion through interparticle voids.

  4. Results from the low level mercury sorbent test at the Oak Ridge Y-12 Plant in Tennessee.

    PubMed

    Hollerman, W; Holland, L; Ila, D; Hensley, J; Southworth, G; Klasson, T; Taylor, P; Johnston, J; Turner, R

    1999-09-10

    A mercury sorbent test was performed near the headwaters of the Upper East Fork Poplar Creek at the Oak Ridge Y-12 Plant in Tennessee. The sorbents SIR-200 (ResinTech), Keyle:X (SolmeteX), and GT-73 (Rohm and Haas) were the best materials tested for low level mercury removal. Each of these sorbents has a thiol-based active site. None of the tested sorbents reduced the mercury concentration to less than the existing 12 ng/l NPDES limit. For this small scale test, SIR-200, Keyle:X, and GT-73 reduced the mercury concentration to less than 51 ng/l, which is a regulatory treatment goal. The other sorbents tested, including granular activated carbon (Filtrasorb 300), did not reduce the mercury concentration below 51 ng/l at any tested flow up to 5 bed volumes per minute. Because of the cost and large volume of sorbent, a wastewater treatment plant for this stream would be prohibitively expensive to construct and maintain.

  5. ASSESSMENT OF LOW COST NOVEL SORBENTS FOR COAL-FIRED POWER PLANT MERCURY CONTROL

    SciTech Connect

    Trevor Ley

    2003-07-01

    This is a Technical Report under a program funded by the Department of Energy's National Energy Technology Laboratory (NETL) to obtain the necessary information to assess the viability of lower cost alternatives to commercially available activated carbon for mercury control in coal-fired utilities. During this reporting period, ongoing tests and analysis on samples from Powerton and Valley to yield waste characterization results for the COHPAC long-term tests were conducted. A draft final report for the sorbent evaluations at Powerton was submitted. Sorbent evaluations at Valley Power Plant were completed on April 24, 2003. Data analysis and reporting for the Valley evaluations are continuing. A statement of work for sorbent evaluations at We Energies' Pleasant Prairie Power Plant was submitted and approved. Work will begin late August 2003. A no cost time extension was granted by DOE/NETL.

  6. Removal of dissolved textile dyes from wastewater by a compost sorbent

    USGS Publications Warehouse

    Tsui, L.S.; Roy, W.R.; Cole, M.A.

    2003-01-01

    The objective of this study was to evaluate the potential for treating dye-contaminated waste streams by sorption using compost as a low-cost sorbent. A mature, thermophilic compost sample was used to sorb CI Acid Black 24, CI Acid Orange 74, CI Basic Blue 9, CI Basic Green 4, CI Direct Blue 71, CI Direct Orange 39, CI Reactive Orange 16 and CI Reactive Red 2 from solution using a batch-sorption method. With the exception of the two reactive dyes, the sorption kinetics were favourable for a continuous-flow treatment process with the compost-dye mixtures reaching a steady state within 3-5 h. Based on limited comparisons, the affinity of the compost for each dye appeared to be competitive with other non-activated carbon sorbents. The results suggest that additional research on using compost as a sorbent for dye-contaminated solutions is warranted.

  7. Decontamination formulation with sorbent additive

    DOEpatents

    Tucker; Mark D. , Comstock; Robert H.

    2007-10-16

    A decontamination formulation and method of making that neutralizes the adverse health effects of both chemical and biological compounds, especially chemical warfare (CW) and biological warfare (BW) agents, and toxic industrial chemicals. The formulation provides solubilizing compounds that serve to effectively render the chemical and biological compounds, particularly CW and BW compounds, susceptible to attack, and at least one reactive compound that serves to attack (and detoxify or kill) the compound. The formulation includes at least one solubilizing agent, a reactive compound, a bleaching activator, a sorbent additive, and water. The highly adsorbent, water-soluble sorbent additive (e.g., sorbitol or mannitol) is used to "dry out" one or more liquid ingredients, such as the liquid bleaching activator (e.g., propylene glycol diacetate or glycerol diacetate) and convert the activator into a dry, free-flowing powder that has an extended shelf life, and is more convenient to handle and mix in the field.

  8. Comparative studies of multi-walled carbon nanotubes (MWNTs) and octadecyl (C18) as sorbents in passive sampling devices for biomimetic uptake of polycyclic aromatic hydrocarbons (PAHs) from soils.

    PubMed

    Li, Shibin; Anderson, Todd A; Maul, Jonathan D; Shrestha, Babina; Green, Micah J; Cañas-Carrell, Jaclyn E

    2013-09-01

    To avoid overestimating the risk of polycyclic aromatic hydrocarbons (PAHs), research is needed to evaluate the bioavailable portion of PAHs in the environment. However, limited PSDs were developed for a terrestrial soil system. In this study, two sorbents, octadecyl (C18) and multi-walled carbon nanotubes (MWNTs), were individually evaluated as sorbents in passive sampling devices (PSDs) as biomimetic samplers to assess the uptake of PAHs from soil. C18-PSDs were an excellent biomimetic tool for PAHs with a low molecular weight in complex exposure conditions with different soil types, types of PAHs, aging periods, and initial PAH concentrations in soil. The utility of MWNT-PSDs was limited by extraction efficiencies of PAHs from MWNTs. However, when compared to C18-PSDs, they had higher adsorption capacities and were less expensive. This study provides data regarding useful techniques that can be used in risk assessment to assess the bioavailability of PAHs in soil.

  9. Effect of the decationization of brown coal from the Kansk-Achinsk Basin on the physicochemical properties of the resulting sorbents

    SciTech Connect

    P.N. Kuznetsov; L.I. Kuznetsova; E.A. Kutikhina

    2008-06-15

    Data are presented on the effect of the decationization of brown coal from the Kansk-Achinsk Basin with a dilute solution of hydrochloric acid on the structural characteristics of the resulting sorbents and the sorption capacities for iodine and phenol. It was found that the partial removal of metal cations (among which calcium was predominant) resulted in the formation of carbonization products with low reactivity upon steam activation. As compared with sorbents prepared from the parent coal under the same conditions, the sorbents from the decationized coal exhibited lower pore volumes, specific surface areas, and sorption capacities. To prepare efficient low-ash sorbents from decationized coal, a longer activation treatment is required.

  10. Engineered Structured Sorbents for the Adsorption of Carbon Dioxide and Water Vapor from Manned Spacecraft Atmospheres: Applications and Testing 2008/2009

    NASA Technical Reports Server (NTRS)

    Howard, David F.; Perry, Jay L.; Knox, James C.; Junaedi, Christian

    2009-01-01

    This paper describes efforts to improve on typical packed beds of sorbent pellets by making use of structured sorbents and alternate bed configurations to improve system efficiency and reliability. The benefits of the alternate configurations include increased structural stability gained by eliminating clay bound zeolite pellets that tend to fluidize and erode, and better thermal control during sorption to increase process efficiency. Test results that demonstrate such improvements are described and presented.

  11. Method and apparatus for separating gases based on electrically and magnetically enhanced monolithic carbon fiber composite sorbents

    DOEpatents

    Judkins, R.R.; Burchell, T.D.

    1999-07-20

    A method for separating gases or other fluids involves placing a magnetic field on a monolithic carbon fiber composite sorption material to more preferentially attract certain gases or other fluids to the sorption material to which a magnetic field is applied. This technique may be combined with the known pressure swing adsorption'' technique utilizing the same sorption material. 1 fig.

  12. Method and apparatus for separating gases based on electrically and magnetically enhanced monolithic carbon fiber composite sorbents

    DOEpatents

    Judkins, Roddie R.; Burchell, Timothy D.

    1999-01-01

    A method for separating gases or other fluids involves placing a magnetic field on a monolithic carbon fiber composite sorption material to more preferentially attract certain gases or other fluids to the sorption material to which a magnetic field is applied. This technique may be combined with the known "pressure swing adsorption" technique utilizing the same sorption material.

  13. Sorbent Mass Variation Method: A New Possibility for the Determination of Binding Isotherms.

    PubMed

    Nagy, Miklós; Siegl, Zoltán; Szili, Krisztina; Fábos, Viktória; Kántor, Krisztina

    2016-06-28

    Measurement of equilibrium mass fraction of a surfactant as a function of the sorbent mass fraction was performed on gel sorbent-solution systems in order to determine binding isotherms and to calculate fundamental characteristics of the solvation layer. With application of this new method, it was possible to calculate specific solvation/sorption capacity and absolute average local composition of the solvation layer. It has been pointed out by systematic variation of the composition (hydrophobicity) and degree of cross-linking of the gel sorbents that the ratio of components in the solvation layer can be constant in a given range of equilibrium mass fraction of the sodium dodecyl sulfate (SDS) and that the specific solvation/sorption capacity of gel sorbents can be much greater than that of activated carbon type adsorbents. On the basis of a mixed sorbent model, it turned out from calculations that there is no preferential binding of SDS close to the chemical cross-links and that the surfactant molecules prefer vinyl acetate groups as binding sites. The density of cross-links regulates the aggregation number of the bound surfactant as well. For loose gels, both binding isotherms and swelling curves show that the surfactant-polymer interaction is a strongly cooperative process. The result of these experiments may influence the general concept of solvation/sorption isotherms and all related phenomena.

  14. Evaluation of Sorbent Injection for Mercury Control

    SciTech Connect

    Sharon Sjostrom

    2005-12-30

    The power industry in the U.S. is faced with meeting new regulations to reduce the emissions of mercury compounds from coal-fired plants. These regulations are directed at the existing fleet of nearly 1,100 boilers. These plants are relatively old with an average age of over 40 years. Although most of these units are capable of operating for many additional years, there is a desire to minimize large capital expenditures because of the reduced (and unknown) remaining life of the plant to amortize the project. Injecting a sorbent such as powdered activated carbon into the flue gas represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. This is the final site report for tests conducted at Laramie River Station Unit 3, one of five sites evaluated in this DOE/NETL program. The overall objective of the test program is to evaluate the capabilities of activated carbon injection at five plants: Sunflower Electric's Holcomb Station Unit 1, AmerenUE's Meramec Station Unit 2, Missouri Basin Power Project's Laramie River Station Unit 3, Detroit Edison's Monroe Power Plant Unit 4, and AEP's Conesville Station Unit 6. These plants have configurations that together represent 78% of the existing coal-fired generation plants. The goals for the program established by DOE/NETL are to reduce the uncontrolled mercury emissions by 50 to 70% at a cost 25 to 50% lower than the benchmark established by DOE of $60,000/lb mercury removed. The goals of the program were exceeded at Laramie River Station by achieving over 90% mercury removal at a sorbent cost of $3,980/lb ($660/oz) mercury removed for a coal mercury content of 7.9 lb/TBtu.

  15. Mathematical evaluation of activated carbon adsorption for surfactant recovery in a soil washing process.

    PubMed

    Ahn, Chi K; Lee, Min W; Lee, Dae S; Woo, Seung H; Park, Jong M

    2008-12-15

    The performances of various soil washing processes, including surfactant recovery by selective adsorption, were evaluated using a mathematical model for partitioning a target compound and surfactant in water/sorbent system. Phenanthrene was selected as a representative hazardous organic compound and Triton X-100 as a surfactant. Two activated carbons that differed in size (Darco 20-40 mesh and >100 mesh sizes) were used in adsorption experiments. The adsorption isotherms of the chemicals were used in model simulations for various washing scenarios. The optimal process conditions were suggested to minimize the dosage of activated carbon and surfactant and the number of washings. We estimated that the requirement of surfactant could be reduced to 33% of surfactant requirements (from 265 to 86.6g) with a reuse step using 9.1g activated carbon (>100 mesh) to achieve 90% removal of phenanthrene (initially 100mg kg-soil(-1)) with a water/soil ratio of 10.

  16. Magnetic sorbents added to soil slurries lower Cr aqueous concentration

    NASA Astrophysics Data System (ADS)

    Aravantinos, Konstantinos; Isari, Ekavi; Karapanagioti, Hrissi K.; Manariotis, Ioannis D.; Werner, David

    2016-04-01

    Activated carbon (AC) acts as a strong binding agent that lowers the pollutant concentration and, thus its toxicity. Another promising sorbent material in environmental applications is biochar (BC) which is obtained from the incomplete combustion of carbon-rich biomass under oxygen-limited conditions. Both of these materials could be used as soil or sediment amendments that would lower the toxicity in the aqueous phase. A draw back of this technique is that although the pollutant will remain non- bioavailable for many years being sorbed into these sorbents, it actually stays into the system. The objective of this study was (a) to synthesize a magnetic powdered activated carbon (AC/Fe) and magnetic powdered biochar (BC/Fe) produced from a commercial AC sample and BC, respectively and (b) to evaluate the potential use of AC/Fe and BC/Fe to lower Cr concentration that desorb from two soils in their soil slurries. The two soil samples originate from the vicinity of a local metal shop. The BC was produced from olive pomace. The surface area, the pore volume, and the average pore size of each sorbent were determined using gas (N2) adsorption-desorption cycles and the Brunauer, Emmett, and Teller (BET) equation. Isotherms with 30 adsorption and 20 desorption points were conducted at liquid nitrogen temperature (77K). Open surface area and micropore volume were determined using t-plot method and Harkins & Jura equation. For both AC/Fe, surface area measurements resulted in 66% those of corresponding AC. For BC/Fe, the surface area was 82% that of BC. Our previous studies have shown that both AC/Fe and BC/Fe are effective sorbents for mercury in aqueous solutions but with lower sorption capacity compared to the initial materials (50-75% lower). Batch experiments with all sorbent samples and each soil were conducted at room temperature (25oC) in order to compare the sorption properties of the materials. The soil slurries demonstrated low Cr concentrations (10.9 and 14.6

  17. Tributyltin sorption to marine sedimentary black carbon and to amended activated carbon.

    PubMed

    Brändli, Rahel C; Breedveld, Gijsbert D; Cornelissen, Gerard

    2009-03-01

    Under marine conditions, tributyltin (TBT) is speciated mainly as an uncharged hydroxyl complex (TBTOH) that is expected to have a similar fate to hydrophobic organic contaminants. Earlier studies indicated that for the later compounds, sorption to black carbon (BC) can be more than two orders of magnitude stronger than sorption to organic carbon, notably at low and environmentally relevant concentrations. The aim of the present study was to investigate the sorption strength of spiked TBT to a sediment and its BC isolate. It was observed that carbon-normalized sorption coefficients were in the same range for the sediment total organic carbon (TOC) and for its BC (log K(TOC) 5.05 L/kg(TOC) and log K(BC) 5.09 L/kg(BC), respectively). This indicates that TBT does not sorb as strongly to BC as other hydrophobic organic contaminants. Activated carbon (AC), a strong man-made sorbent, has the potential to be used for in situ remediation of contaminated sediments and soils, in particular for polycyclic aromatic hydrocarbons and polychlorinated biphenyls. In the present study, both granular and powdered AC were found to strongly sorb TBT under marine conditions, with a log sorption coefficient of 6.8 L/kg(carbon). Tributyl- and dibutyltin concentrations in the pore water of a natively contaminated sediment were reduced by more than 70% on addition of 2% of powdered AC, whereas granular AC did not show a similar reduction. The results indicate that powdered AC might be a feasible remediation agent for sediments contaminated by organotins.

  18. Replacement of charcoal sorbent in the VOST

    SciTech Connect

    Johnson, L.D.; Fuerst, R.G.; Foster, A.L.; Bursey, J.T.

    1993-01-01

    EPA Method 0030, the Volatile Organic Sampling Train (VOST), for sampling volatile organics from stationary sources, specifies the use of petroleum-base charcoal in the second sorbent tube. Charcoal has proven to be a marginal performer as a sampling sorbent, partly due to inconsistency in analyte recovery. In addition, commercial availability of petroleum charcoal for VOST tubes has been variable. Lack of data on comparability and variability of charcoals for VOST application has created uncertainty when other charcoals are substituted. Five potential sorbent replacements for charcoal in Method 0030 were evaluated along with a reference charcoal. Two of the sorbents tested, Ambersorb XE-340 and Tenax GR, did not perform well enough to qualify as replacements. Three candidates, Anasorb 747, Carbosieve S-III and Kureha Beaded Activated Charcoal, performed adequately, and produced statistically equivalent results. Anasorb 747 appears to be an acceptable replacement for petroleum charcoal, based on a combination of performance, availability, and cost.

  19. Photoconductivity of activated carbon fibers

    SciTech Connect

    Kuriyama, K.; Dresselhaus, M.S. )

    1990-08-01

    The photoconductivity is measured on a high-surface-area disordered carbon material, namely activated carbon fibers, to investigate their electronic properties. Measurements of decay time, recombination kinetics and temperature dependence of the photoconductivity generally reflect the electronic properties of a material. The material studied in this paper is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000--2000m{sup 2}/g. Our preliminary thermopower measurements suggest that this carbon material is a p-type semiconductor with an amorphous-like microstructure. The intrinsic electrical conductivity, on the order of 20S/cm at room temperature, increases with increasing temperature in the range 30--290K. In contrast with the intrinsic conductivity, the photoconductivity in vacuum decreases with increasing temperature. The recombination kinetics changes from a monomolecular process at room temperature to a biomolecular process at low temperatures. The observed decay time of the photoconductivity is {approx equal}0.3sec. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The intrinsic carrier density and the activation energy for conduction are estimated to be {approx equal}10{sup 21}/cm{sup 3} and {approx equal}20meV, respectively. The majority of the induced photocarriers and of the intrinsic carriers are trapped, resulting in the long decay time of the photoconductivity and the positive temperature dependence of the conductivity. 54 refs., 11 figs., 3 tabs.

  20. Photoconductivity of Activated Carbon Fibers

    DOE R&D Accomplishments Database

    Kuriyama, K.; Dresselhaus, M. S.

    1990-08-01

    The photoconductivity is measured on a high-surface-area disordered carbon material, namely activated carbon fibers, to investigate their electronic properties. Measurements of decay time, recombination kinetics and temperature dependence of the photoconductivity generally reflect the electronic properties of a material. The material studied in this paper is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000--2000m{sup 2}/g. Our preliminary thermopower measurements suggest that this carbon material is a p-type semiconductor with an amorphous-like microstructure. The intrinsic electrical conductivity, on the order of 20S/cm at room temperature, increases with increasing temperature in the range 30--290K. In contrast with the intrinsic conductivity, the photoconductivity in vacuum decreases with increasing temperature. The recombination kinetics changes from a monomolecular process at room temperature to a biomolecular process at low temperatures. The observed decay time of the photoconductivity is {approx equal}0.3sec. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The intrinsic carrier density and the activation energy for conduction are estimated to be {approx equal}10{sup 21}/cm{sup 3} and {approx equal}20meV, respectively. The majority of the induced photocarriers and of the intrinsic carriers are trapped, resulting in the long decay time of the photoconductivity and the positive temperature dependence of the conductivity.

  1. Solvent-regenerated activated carbon

    SciTech Connect

    McLaughlin, H. )

    1988-07-01

    This report summarizes the results of a University/Industry research project, sponsored by the New York State Energy Research and Development Authority and Fluids Design Corporation. The research project studied the solvent regeneration of activated carbon. Activate carbon was used to remove trace organics from aqueous streams, then regenerated by desorbing the adsorbates with organic solvents. The project included a survey of the potential applications in New York State industries, fundamental research on the adsorption/desorption phenomena, and design of a full-scale process. The economics of the full-scale process were evaluated and compared to alternate available technologies. The result of this work is a versatile process with attractive economics. A wide range of adsorbates and solvents were found to be acceptable for this process. The design methodologies are developed and the techniques for evaluating a new application are delineated. 13 refs., 12 figs., 4 tabs.

  2. Carbon coated titanium dioxide nanotubes: synthesis, characterization and potential application as sorbents in dispersive micro solid phase extraction.

    PubMed

    García-Valverde, M T; Lucena, R; Galán-Cano, F; Cárdenas, S; Valcárcel, M

    2014-05-23

    In this article, carbon coated titanium dioxide nanotubes (c-TNTs) have been synthesized. The synthesis of the bare TNTs (b-TNTs) using anatase as precursor and their coating with a caramel layer have been performed by simple and cheap hydrothermal processes. The final conversion of the caramel layer in a carbon coating has been accomplished by a thermal treatment (600°C) in an inert (Ar) atmosphere. The c-TNTs have been characterized by different techniques including transmission microscopy, infrared spectroscopy, X-ray powder diffraction, thermogravimetry and Brunauer, Emmett and Teller (BET) adsorption isotherms. The extraction performance of the c-TNTs under a microextraction format has been evaluated and compared with that provided by b-TNTs and multiwalled carbon nanotubes (MWCNTs) using naproxen and ketoprofen as model analytes. c-TNTs provided better results than the other nanoparticles, especially at low acidic pH values. In addition, c-TNTs presented a better dispersibility than MWCNTs, which is very interesting for their use in dispersive micro-solid phase extraction. Finally, a microextraction format, adapted to low sample volumes, has been proposed and applied for the determination of naproxen and ketoprofen in saliva and urine samples by liquid chromatography with UV detection. The results indicate that this approach is promising for the analysis of biological samples. In fact, the recoveries were in the range between 96% and 119% while the precision, expressed as relative standard deviation, was better than 8.5% and 26.3% for urine and saliva, respectively. The detection limits were in the range 34.1-40.8μg/L for saliva samples and 81.1-110μg/L for urine samples.

  3. Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

    NASA Astrophysics Data System (ADS)

    Hlaing, Nwe Ni; Vignesh, K.; Sreekantan, Srimala; Pung, Swee-Yong; Hinode, Hirofumi; Kurniawan, Winarto; Othman, Radzali; Thant, Aye Aye; Mohamed, Abdul Rahman; Salim, Chris

    2016-02-01

    Calcium hydroxide (Ca(OH)2) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH)2 based adsorbents for carbon dioxide (CO2) capture. The effect of CTAB concentration (0.2-0.8 M) on the structure, morphology and CO2 adsorption performance of Ca(OH)2 was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG-DTA) techniques. The phase purity, crystallite size, Brunauer-Emmett-Teller (BET) surface area and CO2 adsorption performance of Ca(OH)2 precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH)2 phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH)2 precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

  4. Advanced Sorbents for Oil-Spill Cleanup: Recent Advances and Future Perspectives.

    PubMed

    Ge, Jin; Zhao, Hao-Yu; Zhu, Hong-Wu; Huang, Jin; Shi, Lu-An; Yu, Shu-Hong

    2016-12-01

    Oil sorbents play a very important part in the remediation processes of oil spills. To enhance the oil-sorption properties and simplify the oil-recovery process, various advanced oil sorbents and oil-collecting devices based on them have been proposed recently. Here, we firstly discuss the design considerations for the fabrication of oil sorbents and describe recently developed oil sorbents based on modification strategy. Then, recent advances regarding oil sorbents mainly based on carbon materials and swellable oleophilic polymers are also presented. Subsequently, some additional properties are emphasized, which are required by oil sorbents to cope with oil spills under extreme conditions or to facilitate the oil-collection processes. Furthermore, some oil-collection devices based on oil sorbents that have been developed recently are shown. Finally, an outlook and challenges for the next generation of oil-spill-remediation technology based on oil-sorbents materials are given.

  5. Regenerable Sorbent for CO2 Removal

    NASA Technical Reports Server (NTRS)

    Alptekin, Gokhan; Jayaraman, Ambal

    2013-01-01

    A durable, high-capacity regenerable sorbent can remove CO2 from the breathing loop under a Martian atmosphere. The system design allows near-ambient temperature operation, needs only a small temperature swing, and sorbent regeneration takes place at or above 8 torr, eliminating the potential for Martian atmosphere to leak into the regeneration bed and into the breathing loop. The physical adsorbent can be used in a metabolic, heat-driven TSA system to remove CO2 from the breathing loop of the astronaut and reject it to the Martian atmosphere. Two (or more) alternating sorbent beds continuously scrub and reject CO2 from the spacesuit ventilation loop. The sorbent beds are cycled, alternately absorbing CO2 from the vent loop and rejecting the adsorbed material into the environment at a high CO2 partial pressure (above 8 torr). The system does not need to run the adsorber at cryogenic temperatures, and uses a much smaller temperature swing. The sorbent removes CO2 via a weak chemical interaction. The interaction is strong enough to enable CO2 adsorption even at 3 to 7.6 torr. However, because the interaction between the surface adsorption sites and the CO2 is relatively weak, the heat input needed to regenerate the sorbent is much lower than that for chemical absorbents. The sorbent developed in this project could potentially find use in a large commercial market in the removal of CO2 emissions from coal-fired power plants, if regulations are put in place to curb carbon emissions from power plants.

  6. Controlled release of isoproturon, imidacloprid, and cyromazine from alginate-bentonite-activated carbon formulations.

    PubMed

    Garrido-Herrera, F J; Gonzalez-Pradas, E; Fernandez-Pérez, M

    2006-12-27

    Different alginate-based systems of isoproturon, imidacloprid, and cyromazine have been investigated in order to obtain controlled release (CR) properties. The basic formulation [sodium alginate (1.50%), pesticide (0.30%), and water] was modified using different amounts of bentonite and activated carbon. The higher values of encapsulation efficiency corresponded to those formulations prepared with higher percentages of activated carbon, showing higher encapsulation efficiency values for isoproturon and imidacloprid than for cyromazine, which has a higher water solubility. The kinetic experiments of imidacloprid/isoproturon release in water have shown us that the release rate is higher in imidacloprid systems than in those prepared with isoproturon. Moreover, it can be deduced that the use of bentonite and/or activated carbon sorbents reduces the release rate of the isoproturon and imidacloprid in comparison with the technical product and with alginate formulation without modifying agents. The highest decrease in release rate corresponds to the formulations prepared with the highest percentage of activated carbon. The water uptake, permeability, and time taken for 50% of the active ingredient to be released into water, T50, were calculated to compare the formulations. On the basis of a parameter of an empirical equation used to fit the pesticide release data, the release of isoproturon and imidacloprid from the various formulations into water is controlled by a diffusion mechanism. The sorption capacity of the sorbents and the permeability of the formulations were the most important factors modulating pesticide release. Finally, a linear correlation of the T50 values and the content of activated carbon in formulations were obtained.

  7. Evaluation of Dry Sorbent Injection Technology for Pre-Combustion CO{sub 2} Capture

    SciTech Connect

    Richardson, Carl; Steen, William; Triana, Eugenio; Machalek, Thomas; Davila, Jenny; Schmit, Claire; Wang, Andrew; Temple, Brian; Lu, Yongqi; Lu, Hong; Zhang, Luzheng; Ruhter, David; Rostam-Abadi, Massoud; Sayyah, Maryam; Ito, Brandon; Suslick, Kenneth

    2013-09-30

    This document summarizes the work performed on Cooperative Agreement DE-FE0000465, “Evaluation of Dry Sorbent Technology for Pre-Combustion CO{sub 2} Capture,” during the period of performance of January 1, 2010 through September 30, 2013. This project involves the development of a novel technology that combines a dry sorbent-based carbon capture process with the water-gas-shift reaction for separating CO{sub 2} from syngas. The project objectives were to model, develop, synthesize and screen sorbents for CO{sub 2} capture from gasified coal streams. The project was funded by the DOE National Energy Technology Laboratory with URS as the prime contractor. Illinois Clean Coal Institute and The University of Illinois Urbana-Champaign were project co-funders. The objectives of this project were to identify and evaluate sorbent materials and concepts that were suitable for capturing carbon dioxide (CO{sub 2}) from warm/hot water-gas-shift (WGS) systems under conditions that minimize energy penalties and provide continuous gas flow to advanced synthesis gas combustion and processing systems. Objectives included identifying and evaluating sorbents that efficiently capture CO{sub 2} from a gas stream containing CO{sub 2}, carbon monoxide (CO), and hydrogen (H{sub 2}) at temperatures as high as 650 °C and pressures of 400-600 psi. After capturing the CO{sub 2}, the sorbents would ideally be regenerated using steam, or other condensable purge vapors. Results from the adsorption and regeneration testing were used to determine an optimal design scheme for a sorbent enhanced water gas shift (SEWGS) process and evaluate the technical and economic viability of the dry sorbent approach for CO{sub 2} capture. Project work included computational modeling, which was performed to identify key sorbent properties for the SEWGS process. Thermodynamic modeling was used to identify optimal physical properties for sorbents and helped down-select from the universe of possible sorbent

  8. A novel sorbent for transport reactors and fluidized bed reactors

    SciTech Connect

    Copeland, R.; Cesario, M.; Gershanovich, Y.; Sibold, J.; Windecker, B.

    1998-12-31

    Coal Fired Gasifier Combined Cycles (GCC) have both high efficiency and very low emissions. GCCs critically need a method of removing the H{sub 2}S produced from the sulfur in the coal from the hot gases. There has been extensive research on hot gas cleanup systems, focused on the use of a zinc oxide based sorbent (e.g., zinc titanate). TDA Research, Inc. (TDA) is developing a novel sorbent with improved attrition resistance for transport reactors and fluidized bed reactors. The authors are testing sorbents at conditions simulating the operating conditions of the Pinon Pine clean coal technology plant. TDA sulfided several different formulations at 538 C and found several that have high sulfur capacity when tested in a fluidized bed reactor. TDA initiated sorbent regeneration at 538 C. The sorbents retained chemical activity with multiple cycles. Additional tests will be conducted to evaluate the best sorbent formulation.

  9. Activated, coal-based carbon foam

    DOEpatents

    Rogers, Darren Kenneth; Plucinski, Janusz Wladyslaw

    2004-12-21

    An ablation resistant, monolithic, activated, carbon foam produced by the activation of a coal-based carbon foam through the action of carbon dioxide, ozone or some similar oxidative agent that pits and/or partially oxidizes the carbon foam skeleton, thereby significantly increasing its overall surface area and concurrently increasing its filtering ability. Such activated carbon foams are suitable for application in virtually all areas where particulate or gel form activated carbon materials have been used. Such an activated carbon foam can be fabricated, i.e. sawed, machined and otherwise shaped to fit virtually any required filtering location by simple insertion and without the need for handling the "dirty" and friable particulate activated carbon foam materials of the prior art.

  10. Activated, coal-based carbon foam

    SciTech Connect

    Rogers, Darren Kenneth; Plucinski, Janusz Wladyslaw

    2009-06-09

    An ablation resistant, monolithic, activated, carbon foam produced by the activation of a coal-based carbon foam through the action of carbon dioxide, ozone or some similar oxidative agent that pits and/or partially oxidizes the carbon foam skeleton, thereby significantly increasing its overall surface area and concurrently increasing its filtering ability. Such activated carbon foams are suitable for application in virtually all areas where particulate or gel form activated carbon materials have been used. Such an activated carbon foam can be fabricated, i.e. sawed, machined and otherwise shaped to fit virtually any required filtering location by simple insertion and without the need for handling the "dirty" and friable particulate activated carbon foam materials of the prior art.

  11. Mycoextraction by Clitocybe maxima combined with metal immobilization by biochar and activated carbon in an aged soil.

    PubMed

    Wu, Bin; Cheng, Guanglei; Jiao, Kai; Shi, Wenjin; Wang, Can; Xu, Heng

    2016-08-15

    To develop an eco-friendly and efficient route to remediate soil highly polluted with heavy metals, the idea of mycoextraction combined with metal immobilization by carbonaceous sorbents (biochar and activated carbon) was investigated in this study. Results showed that the application of carbonaceous amendments decreased acid soluble Cd and Cu by 5.13-14.06% and 26.86-49.58%, respectively, whereas the reducible and oxidizable fractions increased significantly as the amount of carbonaceous amendments added increased. The biological activities (microbial biomass, soil enzyme activities) for treatments with carbonaceous sorbents were higher than those of samples without carbonaceous amendments. Clitocybe maxima (C. maxima) simultaneously increased soil enzyme activities and the total number of microbes. Biochar and activated carbon both showed a positive effect on C. maxima growth and metal accumulation. The mycoextraction efficiency of Cd and Cu in treatments with carbonaceous amendments enhanced by 25.64-153.85% and 15.18-107.22%, respectively, in response to that in non-treated soil, which showed positive correlation to the augment of biochar and activated carbon in soil. Therefore, this work suggested the effectiveness of mycoextraction by C. maxima combined the application of biochar and activated carbon in immobilising heavy metal in contaminated soil.

  12. Sorptive uptake of selenium with magnetite and its supported materials onto activated carbon.

    PubMed

    Kwon, Jae H; Wilson, Lee D; Sammynaiken, R

    2015-11-01

    Kinetic and equilibrium uptake studies of selenite in aqueous solution with synthetic magnetite (Mag-P), commercial magnetite (Mag-C), goethite, activated carbon (AC), and a composite material containing 19% magnetite supported on activated carbon (CM-19) were investigated. Kinetic uptake studies used a one-pot setup at pH 5.26 at variable temperature. Sampling of unbound selenite in-situ was achieved with analytical detection by atomic absorbance. The sorptive uptake at equilibrium and kinetic conditions are listed in descending order: goethite>Mag-P>Mag-C>CM-19. Kinetic uptake parameters reveal that Mag-P showed apparent negative values for the activation energy (E(a)) and the enthalpy of activation (ΔH(‡)), in agreement with a multi-step process for the kinetic uptake of selenite. By contrast, Mag-C, CM-19, and goethite showed positive values for E(a) and ΔH(‡). The uptake properties of the various sorbent materials with selenite are in accordance with the formation of inner- and out-sphere complexes. Leaching of iron from the composite material (CM-19) was attenuated due to the stabilizing effect of the magnetite within the pore sites and the surface of AC. Supported iron oxide nanomaterial composites represent a unique sorbent material with tunable uptake properties toward inorganic selenite in aqueous solution.

  13. High temperature sorbents for oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor)

    1994-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C comprising a porous alumina silicate support, such as zeolite, containing from 1 to 10 percent by weight of ion exchanged transition metal, such as copper or cobalt ions, and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum is described. The activation temperature, oxygen sorption, and reducibility are all improved by the presence of the platinum activator.

  14. Monitoring solid oxide CO2 capture sorbents in action.

    PubMed

    Keturakis, Christopher J; Ni, Fan; Spicer, Michelle; Beaver, Michael G; Caram, Hugo S; Wachs, Israel E

    2014-12-01

    The separation, capture, and storage of CO2 , the major greenhouse gas, from industrial gas streams has received considerable attention in recent years because of concerns about environmental effects of increasing CO2 concentration in the atmosphere. An emerging area of research utilizes reversible CO2 sorbents to increase conversion and rate of forward reactions for equilibrium-controlled reactions (sorption-enhanced reactions). Little fundamental information, however, is known about the nature of the sorbent surface sites, sorbent surface-CO2 complexes, and the CO2 adsorption/desorption mechanisms. The present study directly spectroscopically monitors Na2 O/Al2 O3 sorbent-CO2 surface complexes during adsorption/desorption with simultaneous analysis of desorbed CO2 gas, allowing establishment of molecular level structure-sorption relationships between individual surface carbonate complexes and the CO2 working capacity of sorbents at different temperatures.

  15. Sorption of mercury onto waste material derived low-cost activated carbon

    NASA Astrophysics Data System (ADS)

    Bhakta, Jatindra N.; Rana, Sukanta; Lahiri, Susmita; Munekage, Yukihiro

    2014-11-01

    The present study was performed to develop the low-cost activated carbon (AC) from some waste materials as potential mercury (Hg) sorbent to remove high amount of Hg from aqueous phase. The ACs were prepared from banana peel, orange peel, cotton fiber and paper wastes by pyrolysis and characterized by analyzing physico-chemical properties and Hg sorption capacity. The Brunauer Emmett and Teller surface areas (cotton 138 m2/g; paper 119 m2/g), micropore surface areas (cotton 65 m2/g; paper 54 m2/g) and major constituent carbon contents (cotton 95.04 %; paper 94.4 %) were higher in ACs of cotton fiber and paper wastes than the rest two ACs. The Hg sorption capacities and removal percentages were greater in cotton and paper wastes-derived ACs compared to those of the banana and orange peels. The results revealed that elevated Hg removal ability of cotton and paper wastes-derived ACs is largely regulated by their surface area, porosity and carbon content properties. Therefore, ACs of cotton and paper wastes were identified as potential sorbent among four developed ACs to remove high amount of Hg from aqueous phase. Furthermore, easily accessible precursor material, simple preparation process, favorable physico-chemical properties and high Hg sorption capacity indicated that cotton and paper wastes-derived ACs could be used as potential and low-cost sorbents of Hg for applying in practical field to control the severe effect of Hg contamination in the aquatic environment to avoid its human and environmental health risks.

  16. Development of a prototype regenerable carbon dioxide absorber

    NASA Technical Reports Server (NTRS)

    Onischak, M.

    1976-01-01

    Design information was obtained for a new, regenerable carbon dioxide control system for extravehicular activity life support systems. Solid potassium carbonate was supported in a thin porous sheet form and fabricated into carbon dioxide absorber units. Carbon dioxide and water in the life support system atmosphere react with the potassium carbonate and form potassium bicarbonate. The bicarbonate easily reverts to the carbonate by heating to 150 deg C. The methods of effectively packing the sorbent material into EVA-sized units and the effects of inlet concentrations, flowrate, and temperature upon performance were investigated. The cycle life of the sorbent upon the repeated thermal regenerations was demonstrated through 90 cycles.

  17. A critical evaluation of magnetic activated carbon's potential for the remediation of sediment impacted by polycyclic aromatic hydrocarbons.

    PubMed

    Han, Zhantao; Sani, Badruddeen; Akkanen, Jarkko; Abel, Sebastian; Nybom, Inna; Karapanagioti, Hrissi K; Werner, David

    2015-04-09

    Addition of activated carbon (AC) or biochar (BC) to sediment to reduce the chemical and biological availability of organic contaminants is a promising in-situ remediation technology. But concerns about leaving the adsorbed pollutants in place motivate research into sorbent recovery methods. This study explores the use of magnetic sorbents. A coal-based magnetic activated carbon (MAC) was identified as the strongest of four AC and BC derived magnetic sorbents for polycyclic aromatic hydrocarbons (PAHs) remediation. An 8.1% MAC amendment (w/w, equal to 5% AC content) was found to be as effective as 5% (w/w) pristine AC in reducing aqueous PAHs within three months by 98%. MAC recovery from sediment after three months was 77%, and incomplete MAC recovery had both, positive and negative effects. A slight rebound of aqueous PAH concentrations was observed following the MAC recovery, but aqueous PAH concentrations then dropped again after six months, likely due to the presence of the 23% unrecovered MAC. On the other hand, the 77% recovery of the 8.1% MAC dose was insufficient to reduce ecotoxic effects of fine grained AC or MAC amendment on the egestion rate, growth and reproduction of the AC sensitive species Lumbriculus variegatus.

  18. Evaluation of Sorbent Injection for Mercury Control

    SciTech Connect

    Sharon Sjostrom

    2005-02-02

    The power industry in the U.S. is faced with meeting new regulations to reduce the emissions of mercury compounds from coal-fired plants. These regulations are directed at the existing fleet of nearly 1,100 boilers. These plants are relatively old with an average age of over 40 years. Although most of these units are capable of operating for many additional years, there is a desire to minimize large capital expenditures because of the reduced (and unknown) remaining life of the plant to amortize the project. Injecting a sorbent such as powdered activated carbon into the flue gas represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. The overall objective of the test program described in this quarterly report is to evaluate the capabilities of activated carbon injection at five plants with configurations that together represent 78% of the existing coal-fired generation plants. This technology was successfully evaluated in NETL's Phase I tests at scales up to 150 MW, on plants burning subbituminous and bituminous coals and with ESPs and fabric filters. The tests also identified issues that still need to be addressed, such as evaluating performance on other configurations, optimizing sorbent usage (costs), and gathering longer-term operating data to address concerns about the impact of activated carbon on plant equipment and operations. The four sites identified for testing are Sunflower Electric's Holcomb Station, AmerenUE's Meramec Station, AEP's Conesville Station, and Detroit Edison's Monroe Power Plant. In addition to tests identified for the four main sites, parametric testing at Missouri Basin Power Project's Laramie River Station Unit 3 has been scheduled and made possible through additional costshare participation targeted by team members specifically for tests at Holcomb or a similar plant. This is the fifth quarterly report for this project. Long-term testing was completed at Meramec during this

  19. Evaluation of Sorbent Injection for Mercury Control

    SciTech Connect

    Sharon Sjostrom

    2004-10-29

    The power industry in the U.S. is faced with meeting new regulations to reduce the emissions of mercury compounds from coal-fired plants. These regulations are directed at the existing fleet of nearly 1,100 boilers. These plants are relatively old with an average age of over 40 years. Although most of these units are capable of operating for many additional years, there is a desire to minimize large capital expenditures because of the reduced (and unknown) remaining life of the plant to amortize the project. Injecting a sorbent such as powdered activated carbon into the flue gas represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. The overall objective of the test program described in this quarterly report is to evaluate the capabilities of activated carbon injection at four plants with configurations that together represent 78% of the existing coal-fired generation plants. This technology was successfully evaluated in NETL's Phase I tests at scales up to 150 MW, on plants burning subbituminous and bituminous coals and with ESPs and fabric filters. The tests also identified issues that still need to be addressed, such as evaluating performance on other configurations, optimizing sorbent usage (costs), and gathering longer-term operating data to address concerns about the impact of activated carbon on plant equipment and operations. The four sites identified for testing are Sunflower Electric's Holcomb Station, AmerenUE's Meramec Station, AEP's Conesville Station, and a site burning a blend of bituminous and subbituminous coals with a cold-side ESP. This is the fourth quarterly report for this project. Long-term testing was completed at Holcomb during this reporting period and baseline testing at Meramec was begun. Preliminary results from long-term testing at Holcomb are included in this report. Planning information for the other three sites is also included. In general, quarterly reports will be used

  20. A decontamination system for chemical weapons agents using a liquid solution on a solid sorbent.

    PubMed

    Waysbort, Daniel; McGarvey, David J; Creasy, William R; Morrissey, Kevin M; Hendrickson, David M; Durst, H Dupont

    2009-01-30

    A decontamination system for chemical warfare agents was developed and tested that combines a liquid decontamination reagent solution with solid sorbent particles. The components have fewer safety and environmental concerns than traditional chlorine bleach-based products or highly caustic solutions. The liquid solution, based on Decon Greentrade mark, has hydrogen peroxide and a carbonate buffer as active ingredients. The best solid sorbents were found to be a copolymer of ethylene glycol dimethacrylate and n-lauryl methacrylate (Polytrap 6603 Adsorber); or an allyl methacrylate cross-linked polymer (Poly-Pore E200 Adsorber). These solids are human and environmentally friendly and are commonly used in cosmetics. The decontaminant system was tested for reactivity with pinacolyl methylphosphonofluoridate (Soman, GD), bis(2-chloroethyl)sulfide (Mustard, HD), and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX) by using NMR Spectroscopy. Molybdate ion (MoO(4)(-2)) was added to the decontaminant to catalyze the oxidation of HD. The molybdate ion provided a color change from pink to white when the oxidizing capacity of the system was exhausted. The decontaminant was effective for ratios of agent to decontaminant of up to 1:50 for VX (t(1/2) < or = 4 min), 1:10 for HD (t(1/2) < 2 min with molybdate), and 1:10 for GD (t(1/2) < 2 min). The vapor concentrations of GD above the dry sorbent and the sorbent with decontamination solution were measured to show that the sorbent decreased the vapor concentration of GD. The E200 sorbent had the additional advantage of absorbing aqueous decontamination solution without the addition of an organic co-solvent such as isopropanol, but the rate depended strongly on mixing for HD.

  1. Biochar: a green sorbent to sequester acidic organic contaminants

    NASA Astrophysics Data System (ADS)

    Sigmund, Gabriel; Kah, Melanie; Sun, Huichao; Hofmann, Thilo

    2015-04-01

    Biochar is a carbon rich product of biomass pyrolysis that exhibits a high sorption potential towards a wide variety of inorganic and organic contaminants. Because it is a valuable soil additive and a potential carbon sink that can be produced from renewable resources, biochar has gained growing attention for the development of more sustainable remediation strategies. A lot of research efforts have been dedicated to the sorption of hydrophobic contaminants and metals to biochar. Conversely, the understanding of the sorption of acidic organic contaminants remains limited, and questions remain on the influence of biochar characteristics (e.g. ash content) on the sorption behaviour of acidic organic contaminants. To address this knowledge gap, sorption batch experiments were conducted with a series of structurally similar acidic organic contaminants covering a range of dissociation constant (2,4-D, MCPA, 2,4-DB and triclosan). The sorbents selected for experimentation included a series of 10 biochars covering a range of characteristics, multiwalled carbon nanotubes as model for pure carbonaceous phases, and an activated carbon as benchmark. Overall, sorption coefficient [L/kg] covered six orders of magnitude and generally followed the order 2,4-D < MCPA < 2,4-DB < triclosan. Combining comprehensive characterization of the sorbents with the sorption dataset allowed the discussion of sorption mechanisms and driving factors of sorption. Statistical analysis suggests that (i) partitioning was the main driver for sorption to sorbents with small specific surface area (< 25 m²/g), whereas (ii) specific mechanisms dominated sorption to sorbents with larger specific surface area. Results showed that factors usually not considered for the sorption of neutral contaminants play an important role for the sorption of organic acids. The pH dependent lipophilicity ratio (i.e. D instead of Kow), ash content and ionic strength are key factors influencing the sorption of acidic organic

  2. Adsorption of perfluoroalkyl acids by carbonaceous adsorbents: Effect of carbon surface chemistry.

    PubMed

    Zhi, Yue; Liu, Jinxia

    2015-07-01

    Adsorption by carbonaceous sorbents is among the most feasible processes to remove perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) from drinking and ground waters. However, carbon surface chemistry, which has long been recognized essential for dictating performance of such sorbents, has never been considered for PFOS and PFOA adsorption. Thus, the role of surface chemistry was systematically investigated using sorbents with a wide range in precursor material, pore structure, and surface chemistry. Sorbent surface chemistry overwhelmed physical properties in controlling the extent of uptake. The adsorption affinity was positively correlated carbon surface basicity, suggesting that high acid neutralizing or anion exchange capacity was critical for substantial uptake of PFOS and PFOA. Carbon polarity or hydrophobicity had insignificant impact on the extent of adsorption. Synthetic polymer-based Ambersorb and activated carbon fibers were more effective than activated carbon made of natural materials in removing PFOS and PFOA from aqueous solutions.

  3. Novel regenerable sorbent for mercury capture from flue gases of coal-fired power plant.

    PubMed

    Liu, Yan; Kelly, David J A; Yang, Hongqun; Lin, Christopher C H; Kuznicki, Steve M; Xu, Zhenghe

    2008-08-15

    A natural chabazite-based silver nanocomposite (AgMC) was synthesized to capture mercury from flue gases of coal-fired power plants. Silver nanoparticles were engineered on zeolite through ion-exchange of sodium ions with silver ions, followed by thermal annealing. Mercury sorption test using AgMC was performed at various temperatures by exposing it to either pulse injection of mercury or continuous mercury flow. A complete capture of mercury by AgMC was achieved up to a capture temperature of 250 degrees C. Nano silver particles were shown to be the main active component for mercury capture by amalgamation mechanism. Compared with activated carbon-based sorbents, the sorbent prepared in this study showed a much higher mercury capture capacity and upper temperature limit for mercury capture. More importantly, the mercury captured by the spent AgMC could be easily released for safe disposal and the sorbent regenerated by simple heating at 400 degrees C. Mercury capture tests performed in real flue gas environment showed a much higher level of mercury capture by AgMC than by other potential mercury sorbents tested. In our mercury capture tests, the AgMC exposed to real flue gases showed an increased mercury capture efficiency than the fresh AgMC.

  4. Functionalized sorbent for chemical separations and sequential forming process

    DOEpatents

    Fryxell, Glen E [Kennewick, WA; Zemanian, Thomas S [Richland, WA

    2012-03-20

    A highly functionalized sorbent and sequential process for making are disclosed. The sorbent includes organic short-length amino silanes and organic oligomeric polyfunctional amino silanes that are dispersed within pores of a porous support that form a 3-dimensional structure containing highly functionalized active binding sites for sorption of analytes.

  5. Studies of the regeneration of activated bauxite used as granular sorbent for the control of alkali vapors from hot flue gas of coal combustion

    SciTech Connect

    Lee, S H.D.; Smith, S D; Swift, W M; Johnson, I

    1981-05-01

    Regeneration of activated bauxite was studied by water-leaching and thermal swing (high-temperature desorption) methods. Granular activated bauxite has been identified to be very effective when used as a filter medium (i.e., sorbent) in granular-bed filters to remove gaseous alkali metal compounds from simulated hot flue gas of PFBC. Activated bauxite that had captured alkali chloride vapors was demonstrated to be easily and effectively regenerated for reuse by a simple water-leaching method. Data were obtained on (1) the leaching rate of the adsorbed NaCl, (2) effects on the leaching rate of adsorbed NaCl loading, leaching temperature, and the amount of water, and (3) water retention in activated bauxite after leaching. Observed physical changes and particle attrition of activated bauxite as a result of regeneration are discussed. The sorption mechanisms of activated bauxite toward alkali chloride vapors are interpreted on the basis of (1) the chemical compositions of the leachates from alkali chloride-sorbed activated bauxite and (2) the desorption of adsorbed NaCl vapor from activated bauxite at high temperature.

  6. Zinc titanate sorbents

    DOEpatents

    Gupta, R.P.; Gangwal, S.K.; Jain, S.C.

    1998-02-03

    The present invention provides a zinc titanate sorbent material useful in desulfurization applications. The zinc titanate material is in the form of generally spherical particles of substantially uniform chemical distribution. The sorbent material is capable of absorbing sulfur compounds from a gaseous feed in an amount of at least about 15 weight percent based on the weight of the sorbent. The sorbent material is prepared by a process including: (a) forming a zinc oxide/titanium dioxide dry blend, (b) preparing a substantially uniform aqueous slurry comprising the zinc oxide/titanium dioxide dry blend, organic binder, and at least about 1 weight percent inorganic binder based on the solids weight of the slurry, (c) spray drying the slurry to produce substantially spherical particles, and (d) calcining the particles at a temperature of between about 750 to about 950 C. The dry blend is formed by mixing between about 0.5 to about 2 parts zinc oxide having a median particle size of less than about 0.5 microns, and about 1 part titanium dioxide having a median particle size of less than about 1 micron. The slurry contains substantially no free silica and may be prepared by the process including (1) preparing an aqueous solution of organic binder, (2) adding the dry blend to the aqueous solution of organic binder, and (3) adding the inorganic binder to the solution of organic binder, and blend. Additional reagents, such as a surfactant, may also be incorporated into the sorbent material. The present invention also provides a process for desulfurizing a gaseous stream. The process includes passing a gaseous stream through a reactor containing an attrition resistant zinc titanate sorbent material of the present invention.

  7. Zinc titanate sorbents

    DOEpatents

    Gupta, Raghubir P.; Gangwal, Santosh K.; Jain, Suresh C.

    1998-01-01

    The present invention provides a zinc titanate sorbent material useful in desulfurization applications. The zinc titanate material is in the form of generally spherical particles of substantially uniform chemical distribution. The sorbent material is capable of absorbing sulfur compounds from a gaseous feed in an amount of at least about 15 weight percent based on the weight of the sorbent. The sorbent material is prepared by a process including: (a) forming a zinc oxide/titanium dioxide dry blend, (b) preparing a substantially uniform aqueous slurry comprising the zinc oxide/titanium dioxide dry blend, organic binder, and at least about 1 weight percent inorganic binder based on the solids weight of the slurry, (c) spray drying the slurry to produce substantially spherical particles, and (d) calcining the particles at a temperature of between about 750.degree. C. to about 950.degree. C. The dry blend is formed by mixing between about 0.5 to about 2 parts zinc oxide having a median particle size of less than about 0.5 .mu., and about 1 part titanium dioxide having a median particle size of less than about 1 .mu.. The slurry contains substantially no free silica and may be prepared by the process including (1) preparing an aqueous solution of organic binder, (2) adding the dry blend to the aqueous solution of organic binder, and (3) adding the inorganic binder to the solution of organic binder, and blend. Additional reagents, such as a surfactant, may also be incorporated into the sorbent material. The present invention also provides a process for desulfurizing a gaseous stream. The process includes passing a gaseous stream through a reactor containing an attrition resistant zinc titanate sorbent material of the present invention.

  8. Technique for surface oxidation of activated carbon

    SciTech Connect

    Sircar, S.; Golden, T.C.

    1987-10-27

    A method of activating a carbon adsorbent is described, which comprises oxidizing the surface of the carbon adsorbent with a mild oxidizing acid in the presence of a metal oxidation catalyst at an elevated temperature and boiling the mixture of the carbon adsorbent, mild oxidizing acid and metal oxidation catalyst to dryness. Then rinse the surface oxidizing carbon adsorbent with water; and dry the rinsed surface oxidized carbon adsorbent. In a process for the removal of water or carbon dioxide from a gas stream containing water or carbon dioxide of the type wherein the gas stream containing water or carbon dioxide is contacted with a solid phase adsorbent under pressure-swing adsorption or thermal-swing adsorption processing conditions, the improvement is described comprising utilizing an adsorbent produced by the activation of a carbon adsorbent. The activation comprises oxidizing the surface of the carbon adsorbent with a mold oxidizing acid in the presence of a metal oxidation catalyst at an elevated temperature and boiling the mixture of the carbon adsorbent, mild oxidizing acid and metal oxidation catalyst to dryness. Then rinse the surface oxidized carbon adsorbent with water; and dry the rinsed surface oxidized carbon adsorbent.

  9. Space-filling polyhedral sorbents

    DOEpatents

    Haaland, Peter

    2016-06-21

    Solid sorbents, systems, and methods for pumping, storage, and purification of gases are disclosed. They derive from the dynamics of porous and free convection for specific gas/sorbent combinations and use space filling polyhedral microliths with facial aplanarities to produce sorbent arrays with interpenetrating interstitial manifolds of voids.

  10. Adsorption of carbon monoxide on activated carbon tin ligand

    NASA Astrophysics Data System (ADS)

    Mohamad, A. B.; Iyuke, S. E.; Daud, W. R. W.; Kadhum, A. A. H.; Fisal, Z.; Al-Khatib, M. F.; Shariff, A. M.

    2000-09-01

    Activated carbon was impregnated with 34.57% SnCl 2·2H 2O salt and then dried at 180°C to produce AC-SnO 2 to improve its adsorptive interaction with CO. Besides the fact that activated carbon has its original different pore sizes for normal gas phase CO adsorption (as in the case of pure carbon), the impregnated carbon has additional CO adsorption ability due to the presence of O -(ads) on the active sites. AC-SnO 2 proved to be a superior adsorber of CO than pure carbon when used for H 2 purification in a PSA system. Discernibly, the high adsorptive selectivity of AC-SnO 2 towards gas phase CO portrays a good future for the applicability of this noble adsorbent, since CO has become a notorious threat to the global ecosystem due to the current level of air pollution.

  11. [Study on influence between activated carbon property and immobilized biological activated carbon purification effect].

    PubMed

    Wang, Guang-zhi; Li, Wei-guang; He, Wen-jie; Han, Hong-da; Ding, Chi; Ma, Xiao-na; Qu, Yan-ming

    2006-10-01

    By means of immobilizing five kinds of activated carbon, we studied the influence between the chief activated carbon property items and immobilized bioactivated carbon (IBAC) purification effect with the correlation analysis. The result shows that the activated carbon property items which the correlation coefficient is up 0.7 include molasses, abrasion number, hardness, tannin, uniform coefficient, mean particle diameter and effective particle diameter; the activated carbon property items which the correlation coefficient is up 0.5 include pH, iodine, butane and tetrachloride. In succession, the partial correlation analysis shows that activated carbon property items mostly influencing on IBAC purification effect include molasses, hardness, abrasion number, uniform coefficient, mean particle diameter and effective particle diameter. The causation of these property items bringing influence on IBAC purification is that the activated carbon holes distribution (representative activated carbon property item is molasses) provides inhabitable location and adjust food for the dominance bacteria; the mechanical resist-crash property of activated carbon (representative activated carbon property items: abrasion number and hardness) have influence on the stability of biofilm; and the particle diameter size and distribution of activated carbon (representative activated carbon property items: uniform coefficient, mean particle diameter and effective particle diameter) can directly affect the force of water in IBAC filter bed, which brings influence on the dominance bacteria immobilizing on activated carbon.

  12. ASSESSMENT OF LOW COST NOVEL SORBENTS FOR COAL-FIRED POWER PLANT MERCURY CONTROL

    SciTech Connect

    Trevor Ley

    2004-01-01

    This is a Technical Report under a program funded by the Department of Energy's National Energy Technology Laboratory (NETL) to obtain the necessary information to assess the viability of lower cost alternatives to commercially available activated carbon for mercury control in coal-fired utilities. Novel sorbent evaluations at We Energies' Pleasant Prairie Power Plant (P4) Unit 1 (no SCR in place) have been completed. Nineteen sorbents were evaluated for mercury control. A batch injection rate of 1 lb/Mmacf for 1 hour was conducted for screening purposes at a temperature of 300 F. Four sorbents were further evaluated at three injection rates and two temperatures. The multi-pollutant control test system (PoCT) was installed on P4's Unit 2 (with an SCR) and sorbent evaluations are continuing. Evaluations will continue through the end of January 2004. Tests and analysis on samples from Powerton and Valley to yield waste characterization results for the COHPAC long-term tests are continuing. A no-cost time extension for work to be completed by March 31, 2004 was granted by DOE/NETL.

  13. The ADESORB Process for Economical Production of Sorbents for Mercury Removal from Coal Fired Power Plants

    SciTech Connect

    Robin Stewart

    2008-03-12

    The DOE's National Energy Technology Laboratory (NETL) currently manages the largest research program in the country for controlling coal-based mercury emissions. NETL has shown through various field test programs that the determination of cost-effective mercury control strategies is complex and highly coal- and plant-specific. However, one particular technology has the potential for widespread application: the injection of activated carbon upstream of either an electrostatic precipitator (ESP) or a fabric filter baghouse. This technology has potential application to the control of mercury emissions on all coal-fired power plants, even those with wet and dry scrubbers. This is a low capital cost technology in which the largest cost element is the cost of sorbents. Therefore, the obvious solutions for reducing the costs of mercury control must focus on either reducing the amount of sorbent needed or decreasing the cost of sorbent production. NETL has researched the economics and performance of novel sorbents and determined that there are alternatives to the commercial standard (NORIT DARCO{reg_sign} Hg) and that this is an area where significant technical improvements can still be made. In addition, a key barrier to the application of sorbent injection technology to the power industry is the availability of activated carbon production. Currently, about 450 million pounds ($250 million per year) of activated carbon is produced and used in the U.S. each year - primarily for purification of drinking water, food, and beverages. If activated carbon technology were to be applied to all 1,100 power plants, EPA and DOE estimate that it would require an additional $1-$2 billion per year, which would require increasing current capacity by a factor of two to eight. A new facility to produce activated carbon would cost approximately $250 million, would increase current U.S. production by nearly 25%, and could take four to five years to build. This means that there could be

  14. Physical and Chemical Properties of Pan-Derived Electrospun Activated Carbon Nanofibers and Their Potential for Use As An Adsorbent for Toxic Industrial Chemicals (Postprint)

    DTIC Science & Technology

    2012-09-14

    humid) environment. Activated carbons can be hydrophobic and have high micropore vol- ume (relative to zeolites ), are thermally stable, and are re...Brown et al. 1989). Impregnated ad- sorbents cannot be regenerated to initial capacity by thermal or pressure swing if the impregnants are consumed...detected in a series of traps and thermal con- ductivity cells. Oxygen in the sample is determined by mass difference—causing adsorbed water

  15. Regenerable sorbent technique for capturing CO.sub.2 using immobilized amine sorbents

    DOEpatents

    Pennline, Henry W; Hoffman, James S; Gray, McMahan L; Fauth, Daniel J; Resnik, Kevin P

    2013-08-06

    The disclosure provides a CO.sub.2 absorption method using an amine-based solid sorbent for the removal of carbon dioxide from a gas stream. The method disclosed mitigates the impact of water loading on regeneration by utilizing a conditioner following the steam regeneration process, providing for a water loading on the amine-based solid sorbent following CO.sub.2 absorption substantially equivalent to the moisture loading of the regeneration process. This assists in optimizing the CO.sub.2 removal capacity of the amine-based solid sorbent for a given absorption and regeneration reactor size. Management of the water loading in this manner allows regeneration reactor operation with significant mitigation of energy losses incurred by the necessary desorption of adsorbed water.

  16. Inorganic ion sorbent method

    DOEpatents

    Teter, David M.; Brady, Patrick V.; Krumhansl, James L.

    2007-07-17

    A process and medium for decontamination of water containing anionic species including arsenic and chromium, wherein compounds comprising divalent and trivalent metal oxides and sulfides are used to form surface complexes with contaminants under pH conditions within the range of potable water. In one embodiment natural and synthetic spinels and spinel-like materials are used as the sorbent substance.

  17. Inorganic ion sorbents

    DOEpatents

    Teter, David M.; Brady, Patrick V.; Krumhansl, James L.

    2006-10-17

    A process and medium for decontamination of water containing anionic species including arsenic and chromium, wherein compounds comprising divalent and trivalent metal oxides and sulfides are used to form surface complexes with contaminants under pH conditions within the range of potable water. In one embodiment natural and synthetic spinels and spinel-like materials are used as the sorbent substance.

  18. Solid-phase extraction of galloyl- and caffeoylquinic acids from natural sources (Galphimia glauca and Arnicae flos) using pure zirconium silicate and bismuth citrate powders as sorbents inside micro spin columns.

    PubMed

    Hussain, Shah; Schönbichler, Stefan A; Güzel, Yüksel; Sonderegger, Harald; Abel, Gudrun; Rainer, Matthias; Huck, Christian W; Bonn, Günther K

    2013-10-01

    Galloyl- and caffeoylquinic acids are among the most important pharmacological active groups of natural compounds. This study describes a pre-step in isolation of some selected representatives of these groups from biological samples. A selective solid-phase extraction (SPE) method for these compounds may help assign classes and isomer designations within complex mixtures. Pure zirconium silicate and bismuth citrate powders (325 mesh) were employed as two new sorbents for optimized SPE of phenolic acids. These sorbents possess electrostatic interaction sites which accounts for additional interactions for carbon acid moieties as compared to hydrophilic and hydrophobic sorbents alone. Based on this principle, a selective SPE method for 1,3,4,5-tetragalloylquinic acid (an anti-HIV and anti-asthamatic agent) as a starting compound was developed and then deployed upon other phenolic acids with success. The recoveries and selectivities of both sorbents were compared to most commonly applied and commercially available sorbents by using high performance liquid chromatography. The nature of interaction between the carrier sorbent and the acidic target molecules was investigated by studying hydrophilic (silica), hydrophobic (C18), mixed-mode (ionic and hydrophobic: Oasis(®) MAX) and predominantly electrostatic (zirconium silicate) materials. The newly developed zirconium silicate and bismuth citrate stationary phases revealed promising results for the selective extraction of galloyl- and caffeoylquinic acids from natural sources. It was observed that zirconium silicate exhibited maximum recovery and selectivity for tetragalloylquinic acid (84%), chlorogenic acid (82%) and dicaffeoylquinic acid (94%) among all the tested sorbents.

  19. Evaluation of Sorbent Injection for Mercury Control

    SciTech Connect

    Sharon Sjostrom

    2006-04-30

    The power industry in the U.S. is faced with meeting new regulations to reduce the emissions of mercury compounds from coal-fired plants. These regulations are directed at the existing fleet of nearly 1,100 boilers. These plants are relatively old with an average age of over 40 years. Although most of these units are capable of operating for many additional years, there is a desire to minimize large capital expenditures because of the reduced (and unknown) remaining life of the plant to amortize the project. Injecting a sorbent such as powdered activated carbon into the flue gas represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. This is the final site report for tests conducted at DTE Energy's Monroe Power Plant, one of five sites evaluated in this DOE/NETL program. The overall objective of the test program was to evaluate the capabilities of activated carbon injection at five plants: Sunflower Electric's Holcomb Station Unit 1, AmerenUE's Meramec Station Unit 2, Missouri Basin Power Project's Laramie River Station Unit 3, Detroit Edison's Monroe Power Plant Unit 4, and AEP's Conesville Station Unit 6. These plants have configurations that together represent 78% of the existing coal-fired generation plants. The goals for the program established by DOE/NETL were to reduce the uncontrolled mercury emissions by 50 to 70% at a cost 25 to 50% lower than the target established by DOE of $60,000/lb mercury removed. The results from Monroe indicate that using DARCO{reg_sign} Hg would result in higher mercury removal (80%) at a sorbent cost of $18,000/lb mercury, or 70% lower than the benchmark. These results demonstrate that the goals established by DOE/NETL were exceeded during this test program. The increase in mercury removal over baseline conditions is defined for this program as a comparison in the outlet emissions measured using the Ontario Hydro method during the baseline and long-term test periods

  20. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 2, Single particle kinetic studies of sulfidation and regeneration reactions of candidate zinc ferrite sorbents

    SciTech Connect

    Silaban, A.; Harrison, D.P.

    1989-05-02

    AMAX Research & Development Center (AMAX R&D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  1. Sorption of boron trifluoride by activated carbons

    SciTech Connect

    Polevoi, A.S.; Petrenko, A.E.

    1988-01-10

    The sorption of born trifluoride on AG-3, SKT, SKT-3, SKT-7, SKT-4A, SKT-6A, and SKT-2B carbons was investigated. The sorption isotherms for both vapors and gas were determined volumetrically. The coefficients of two equations described the sorption of BF/sub 3/ in the sorption of BF/sub 3/ on active carbons. Heats of sorption of BF/sub 3/ on the activated carbons are shown and the sorption isotherms and temperature dependences of the equilibrium pressure of BF/sub 3/ for activated carbons were presented. The values of the heats of sorption indicated the weak character of the reaction of BF/sub 3/ with the surface of the carbons. The equations can be used for calculating the phase equilibrium of BF/sub 3/ on carbons in a wider range of temperatures and pressures.

  2. Catalytic Growth of Macroscopic Carbon Nanofibers Bodies with Activated Carbon

    SciTech Connect

    Abdullah, N.; Muhammad, I. S.; Hamid, S. B. Abd.; Rinaldi, A.; Su, D. S.; Schlogl, R.

    2009-06-01

    Carbon-carbon composite of activated carbon and carbon nanofibers have been synthesized by growing Carbon nanofiber (CNF) on Palm shell-based Activated carbon (AC) with Ni catalyst. The composites are in an agglomerated shape due to the entanglement of the defective CNF between the AC particles forming a macroscopic body. The macroscopic size will allow the composite to be used as a stabile catalyst support and liquid adsorbent. The preparation of CNT/AC nanocarbon was initiated by pre-treating the activated carbon with nitric acid, followed by impregnation of 1 wt% loading of nickel (II) nitrate solutions in acetone. The catalyst precursor was calcined and reduced at 300 deg. C for an hour in each step. The catalytic growth of nanocarbon in C{sub 2}H{sub 4}/H{sub 2} was carried out at temperature of 550 deg. C for 2 hrs with different rotating angle in the fluidization system. SEM and N{sub 2} isotherms show the level of agglomeration which is a function of growth density and fluidization of the system. The effect of fluidization by rotating the reactor during growth with different speed give a significant impact on the agglomeration of the final CNF/AC composite and thus the amount of CNFs produced. The macrostructure body produced in this work of CNF/AC composite will have advantages in the adsorbent and catalyst support application, due to the mechanical and chemical properties of the material.

  3. Catalytic activation of carbon-carbon bonds in cyclopentanones.

    PubMed

    Xia, Ying; Lu, Gang; Liu, Peng; Dong, Guangbin

    2016-11-24

    In the chemical industry, molecules of interest are based primarily on carbon skeletons. When synthesizing such molecules, the activation of carbon-carbon single bonds (C-C bonds) in simple substrates is strategically important: it offers a way of disconnecting such inert bonds, forming more active linkages (for example, between carbon and a transition metal) and eventually producing more versatile scaffolds. The challenge in achieving such activation is the kinetic inertness of C-C bonds and the relative weakness of newly formed carbon-metal bonds. The most common tactic starts with a three- or four-membered carbon-ring system, in which strain release provides a crucial thermodynamic driving force. However, broadly useful methods that are based on catalytic activation of unstrained C-C bonds have proven elusive, because the cleavage process is much less energetically favourable. Here we report a general approach to the catalytic activation of C-C bonds in simple cyclopentanones and some cyclohexanones. The key to our success is the combination of a rhodium pre-catalyst, an N-heterocyclic carbene ligand and an amino-pyridine co-catalyst. When an aryl group is present in the C3 position of cyclopentanone, the less strained C-C bond can be activated; this is followed by activation of a carbon-hydrogen bond in the aryl group, leading to efficient synthesis of functionalized α-tetralones-a common structural motif and versatile building block in organic synthesis. Furthermore, this method can substantially enhance the efficiency of the enantioselective synthesis of some natural products of terpenoids. Density functional theory calculations reveal a mechanism involving an intriguing rhodium-bridged bicyclic intermediate.

  4. Making Activated Carbon by Wet Pressurized Pyrolysis

    NASA Technical Reports Server (NTRS)

    Fisher, John W.; Pisharody, Suresh; Wignarajah, K.; Moran, Mark

    2006-01-01

    A wet pressurized pyrolysis (wet carbonization) process has been invented as a means of producing activated carbon from a wide variety of inedible biomass consisting principally of plant wastes. The principal intended use of this activated carbon is room-temperature adsorption of pollutant gases from cooled incinerator exhaust streams. Activated carbon is highly porous and has a large surface area. The surface area depends strongly on the raw material and the production process. Coconut shells and bituminous coal are the primary raw materials that, until now, were converted into activated carbon of commercially acceptable quality by use of traditional production processes that involve activation by use of steam or carbon dioxide. In the wet pressurized pyrolysis process, the plant material is subjected to high pressure and temperature in an aqueous medium in the absence of oxygen for a specified amount of time to break carbon-oxygen bonds in the organic material and modify the structure of the material to obtain large surface area. Plant materials that have been used in demonstrations of the process include inedible parts of wheat, rice, potato, soybean, and tomato plants. The raw plant material is ground and mixed with a specified proportion of water. The mixture is placed in a stirred autoclave, wherein it is pyrolized at a temperature between 450 and 590 F (approximately between 230 and 310 C) and a pressure between 1 and 1.4 kpsi (approximately between 7 and 10 MPa) for a time between 5 minutes and 1 hour. The solid fraction remaining after wet carbonization is dried, then activated at a temperature of 500 F (260 C) in nitrogen gas. The activated carbon thus produced is comparable to commercial activated carbon. It can be used to adsorb oxides of sulfur, oxides of nitrogen, and trace amounts of hydrocarbons, any or all of which can be present in flue gas. Alternatively, the dried solid fraction can be used, even without the activation treatment, to absorb

  5. Desulfurization of Hydrocarbon Fuels at Ambient Conditions Using Supported Silver Oxide-Titania Sorbents

    DTIC Science & Technology

    2010-12-13

    25 II.6.7 Thermogravimetric analysis----------------------------------------------- 26 II.7 Sorbent pretreatment with probe molecules...different silver loadings -------- 37 Table IV.1. The effect of pretreatment of the support prior to introduction of the precursor on the properties of...of benzothiophene for Ag/TiO2 sorbents where the TiO2 was pretreated with moist air, ammonium carbonate (DP), and conc. HNO3 compared to sorbent

  6. LONG-TERM DEMONSTRATION OF SORBENT ENHANCEMENT ADDITIVE TECHNOLOGY FOR MERCURY CONTROL

    SciTech Connect

    Jason D. Laumb; Dennis L. Laudal; Grant E. Dunham; John P. Kay; Christopher L. Martin; Jeffrey S. Thompson; Nicholas B. Lentz; Alexander Azenkeng; Kevin C. Galbreath; Lucinda L. Hamre

    2011-05-27

    Long-term demonstration tests of advanced sorbent enhancement additive (SEA) technologies have been completed at five coal-fired power plants. The targeted removal rate was 90% from baseline conditions at all five stations. The plants included Hawthorn Unit 5, Mill Creek Unit 4, San Miguel Unit 1, Centralia Unit 2, and Hoot Lake Unit 2. The materials tested included powdered activated carbon, treated carbon, scrubber additives, and SEAs. In only one case (San Miguel) was >90% removal not attainable. The reemission of mercury from the scrubber at this facility prevented >90% capture.

  7. ANASORB{reg_sign} 747 - A universal sorbent for air sampling?

    SciTech Connect

    Harper, M.

    1997-12-31

    A sorbent to be used for air sampling must meet certain performance criteria including sample background, capacity, stability, and recovery. Anasorb{sup R} 747 is a proprietary 20/40 mesh beaded active carbon prepared from raw materials with a very low ash content in a process which creates a regular pore structure. The background is very low for both inorganic and organic species, and the surface is more inert and less hydrophilic than coconut charcoal, while capacity is similar. The low catalytic activity of the surface means samples of many reactive compounds remain stable for longer periods. The sorbent is compatible with most solvent systems in use (e.g. carbon disulfide, methylene chloride, methanol, dimethyformamide). Anasorb 747 can be coated with chemicals for efficient adsorption of inorganic gases, which can be analyzed at very low levels because of low background interference. A large number of validated sampling methods use Anasorb 747, including methods from OSHA and NIOSH, corporate industrial hygiene laboratories, various branches of the EPA, and international agencies. These methods refer to around fifty different gases and vapors. Although this sorbent is not compatible with some compounds (e.g. low molecular weight aldehydes) it is quite close to being of universal application.

  8. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Berggren, M.H.; Jha, M.C.

    1989-10-01

    AMAX Research Development Center (AMAX R D) investigated methods for enhancing the reactivity and durability of zinc ferrite desulfurization sorbents. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For this program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation. Two base case sorbents, a spherical pellet and a cylindrical extrude used in related METC-sponsored projects, were used to provide a basis for the aimed enhancement in durability and reactivity. Sorbent performance was judged on the basis of physical properties, single particle kinetic studies based on thermogravimetric (TGA) techniques, and multicycle bench-scale testing of sorbents. A sorbent grading system was utilized to quantify the characteristics of the new sorbents prepared during the program. Significant enhancements in both reactivity and durability were achieved for the spherical pellet shape over the base case formulation. Overall improvements to reactivity and durability were also made to the cylindrical extrude shape. The primary variables which were investigated during the program included iron oxide type, zinc oxide:iron oxide ratio, inorganic binder concentration, organic binder concentration, and induration conditions. The effects of some variables were small or inconclusive. Based on TGA studies and bench-scale tests, induration conditions were found to be very significant.

  9. Modified clay sorbents

    DOEpatents

    Fogler, H. Scott; Srinivasan, Keeran R.

    1990-01-01

    A novel modified clay sorbent and method of treating industrial effluents to remove trace pollutants, such as dioxins, biphenyls, and polyaromatics such as benzo(a)pyrene and pentachlorophenol. The novel clay sorbent has a composite structure in which the interlayer space of an expandable clay, such as smectite, is filled with polyvalent or multivalent inorganic cations which forces weaker surfactant cations to locate on the surface of the clay in such an orientation that the resulting composite is hydrophilic in nature. A specific example is cetylpyridinium-hydroxy aluminum-montmorillonite. In certain embodiments, a non-expanding clay, such as kaolinite, is used and surfactant cations are necessarily located on an external surface of the clay. A specific example is cetylpyridinium-kaolinite.

  10. Feasibility of CO₂/SO₂ uptake enhancement of calcined limestone modified with rice husk ash during pressurized carbonation.

    PubMed

    Chen, Huichao; Zhao, Changsui; Ren, Qiangqiang

    2012-01-01

    The calcination/carbonation cycle using calcium-based sorbents appears to be a viable method for carbon dioxide (CO₂) capture from combustion gases. Recent attempts to improve the CO₂/SO₂ uptake of a calcium-based sorbent modified by using rice husk ash (RHA) in the hydration process have succeeded in enhancing its effectiveness. The optimal mole ratio of RHA to calcined limestone (M(Si/Ca)) was adjusted to 0.2. The cyclic CO₂ capture characteristics and the SO₂ uptake activity of the modified sorbent were evaluated in a calcination/pressurized carbonation reactor system. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) spectrum of the sorbent were also taken to supplement the study. The results showed that the carbonation conversion was greatly increased for the sorbent with M(Si/Ca) ratio of 0.2. For this sorbent formulation the optimal operating conditions were 700-750 °C and 0.5-0.7 MPa. CO₂ absorption was not proportional to CO₂ concentration in the carbonation atmosphere, but was directly related to reaction time. The CO₂ uptake decreased in the presence of SO₂. SO₂ uptake increased, and the total calcium utilization was maintained over multiple cycles. Analysis has shown that the silicate component is evenly or well distributed, and this serves as a framework to prevent sintering, thus preserving the available microstructure for reaction. The sorbent also displayed high activity to SO₂ absorption and could be used to capture CO₂ and SO₂ simultaneously.

  11. Kinetics of sorption of polyaromatic hydrocarbons onto granular activated carbon and Macronet hyper-cross-linked polymers (MN200).

    PubMed

    Valderrama, C; Cortina, J L; Farran, A; Gamisans, X; Lao, C

    2007-06-01

    Polymeric supports are presented as an alternative to granular activated carbon (GAC) for organic contaminant removal from groundwater using permeable reactive barriers (PRB). The search for suitable polymeric sorbents for hydrocarbon extraction from aqueous streams has prompted the synthesis of new resins incorporating new functionalities or modifying the polymer network properties that solve many of the existing problems. Between them, the new type of polymeric sorbents Macronet Hypersol containing a styrene-divinylbenzene macroporous hyperreticulated network has been evaluated. Because of their potential sorptive properties, tests were conducted to determine the feasibility of using them as a low-cost reactive material for groundwater applications. The present work describes the sorption of six polycyclic hydrocarbons (PAHs) from aqueous solution onto both Macronet polymeric sorbent MN200 and granular activated carbon. Batch experiments were performed to determine loading rates of a family of PAHs (naphthalene, fluorene, anthracene, acenaphthene, pyrene, and fluoranthene), from a simple two-rings PAH (naphthalene) up to a four-ring PAH (pyrene). The behavior of a non-functionalized Macronet support (MN200) was compared with the behavior of a recognized material, granular activated carbon (GAC). Analyses of the respective rate data with three theoretical models (pseudo-first- and pseudo-second-order reaction models and the Elovich model) were used to describe the PAH sorption kinetics. Sorption rate constants were determined by graphical analysis of the proposed models. The study showed that sorption systems followed a pseudo-first-order reaction model, although the pseudo-second-order reaction model provides an acceptable description of the sorption process. Graphical analysis showed that the sorption process with activated carbon is a more complex process than the one observed for hyper-cross-linked polymers (MN200). A simulation of the barrier thickness needed

  12. The transport properties of activated carbon fibers

    SciTech Connect

    di Vittorio, S.L. . Dept. of Materials Science and Engineering); Dresselhaus, M.S. . Dept. of Electrical Engineering and Computer Science Massachusetts Inst. of Tech., Cambridge, MA . Dept. of Physics); Endo, M. . Dept. of Electrical Engineering); Issi, J-P.; Piraux, L.

    1990-07-01

    The transport properties of activated isotropic pitch-based carbon fibers with surface area 1000 m{sup 2}/g have been investigated. We report preliminary results on the electrical conductivity, the magnetoresistance, the thermal conductivity and the thermopower of these fibers as a function of temperature. Comparisons are made to transport properties of other disordered carbons. 19 refs., 4 figs.

  13. Solvent recovery improved with activated carbon fibers

    SciTech Connect

    Not Available

    1982-11-01

    A non-woven net of activated carbon fibers as absorbing media, representing a major advancement in vapor recovery technology, is presented. The carbon fiber exhibits mass transfer coefficients for adsorption description of up to 100 times that of conventional systems.

  14. The Transport Properties of Activated Carbon Fibers

    DOE R&D Accomplishments Database

    di Vittorio, S. L.; Dresselhaus, M. S.; Endo, M.; Issi, J-P.; Piraux, L.

    1990-07-01

    The transport properties of activated isotropic pitch-based carbon fibers with surface area 1000 m{sup 2}/g have been investigated. We report preliminary results on the electrical conductivity, the magnetoresistance, the thermal conductivity and the thermopower of these fibers as a function of temperature. Comparisons are made to transport properties of other disordered carbons.

  15. Chemical activation of carbon mesophase pitches.

    PubMed

    Mora, E; Blanco, C; Pajares, J A; Santamaría, R; Menéndez, R

    2006-06-01

    This paper studies the chemical activation of mesophase pitches of different origins in order to obtain activated carbons suitable for use as electrodes in supercapacitors. The effect that the activating agent (NaOH, LiOH, and KOH), the alkaline hydroxide/pitch ratio, and the activation temperature had on the characteristics of the resultant activated carbons was studied. LiOH was found to be a noneffective activating agent, while activation with NaOH and KOH yielded activated carbons with high apparent surface areas and pore volumes. The increase of the KOH/pitch ratio caused an increase of the chemical attack on the carbon, producing higher burnoffs and development of porosity. Extremely high apparent surface areas were obtained when the petroleum pitch was activated with 5:1 KOH/carbon ratio. The increase of the activation temperature caused an increase of the burnoff, although the differences were not as significant as those derived from the use of different proportions of activating agent.

  16. ACTIVATED CARBON FROM LIGNITE FOR WATER TREATMENT

    SciTech Connect

    Edwin S. Olson; Daniel J. Stepan

    2000-07-01

    High concentrations of humate in surface water result in the formation of excess amounts of chlorinated byproducts during disinfection treatment. These precursors can be removed in water treatment prior to disinfection using powdered activated carbon. In the interest of developing a more cost-effective method for removal of humates in surface water, a comparison of the activities of carbons prepared from North Dakota lignites with those of commercial carbons was conducted. Previous studies indicated that a commercial carbon prepared from Texas lignite (Darco HDB) was superior to those prepared from bituminous coals for water treatment. That the high alkali content of North Dakota lignites would result in favorable adsorptive properties for the very large humate molecules was hypothesized, owing to the formation of larger pores during activation. Since no standard humate test has been previously developed, initial adsorption testing was performed using smaller dye molecules with various types of ionic character. With the cationic dye, methylene blue, a carbon prepared from a high-sodium lignite (HSKRC) adsorbed more dye than the Darco HDB. The carbon from the low-sodium lignite was much inferior. With another cationic dye, malachite green, the Darco HDB was slightly better. With anionic dyes, methyl red and azocarmine-B, the results for the HSKRC and Darco HDB were comparable. A humate test was developed using Aldrich humic acid. The HSKRC and the Darco HDB gave equally high adsorption capacities for the humate (138 mg/g), consistent with the similarities observed in earlier tests. A carbon prepared from a high-sodium lignite from a different mine showed an outstanding improvement (201 mg/g). The carbons prepared from the low-sodium lignites from both mines showed poor adsorption capacities for humate. Adsorption isotherms were performed for the set of activated carbons in the humate system. These exhibited a complex behavior interpreted as resulting from two types

  17. Effect of biochar or activated carbon amendment on the volatilisation and biodegradation of organic soil pollutants

    NASA Astrophysics Data System (ADS)

    Werner, David; Meynet, Paola; Bushnaf, Khaled

    2013-04-01

    Biochar or activated carbon added to contaminated soil may temporarily reduce the volatilisation of organic pollutants by enhanced sorption. The long-term effect of sorbent amendments on the fate of volatile petroleum hydrocarbon mixtures (VPHs) will depend on the responses of the soil bacterial community members, especially those which may utilize VPHs as carbon substrates. We investigated the volatilisation and biodegradation of VPHs emanating from NAPL sources and migrating through one meter long columns containing unsaturated sandy soil with and without 2% biochar or activated carbon amendment. After 420 days, VPH volatilisation from AC amended soil was less than 10 percent of the cumulative VPH volatilisation flux from unamended soil. The cumulative CO2 volatilisation flux increased more slowly in AC amended soil, but was comparable to the untreated soil after 420 days. This indicated that the pollution attenuation over a 1 meter distance was improved by the AC amendment. Biochar was a weaker VPH sorbent than AC and had a lesser effect on the cumulative VPH and CO2 fluxes. We also investgated the predominant bacterial community responses in sandy soil to biochar and/or VPH addition with a factorially designed batch study, and by analyzing preserved soil samples. Biochar addition alone had only weak effects on soil bacterial communities, while VPH addition was a strong community structure shaping factor. The bacterial community effects of biochar-enhanced VPH sorption were moderated by the limited biomass carrying capacity of the sandy soil investigated which contained only low amounts of inorganic nitrogen. Several Pseudomonas spp., including Pseudomonas putida strains, became dominant in VPH polluted soil with and without biochar. The ability of these versatile VPH degraders to effectively regulate their metabolic pathways according to substrate availabilities may additionally have moderated bacterial community structure responses to the presence of biochar

  18. Performance Evaluation of Engineered Structured Sorbents for Atmosphere Revitalization Systems On Board Crewed Space Vehicles and Habitats

    NASA Technical Reports Server (NTRS)

    Howard, David F.; Perry, Jay L.; Knox, James C.; Junaedi, Christian; Roychoudhury, Subir

    2011-01-01

    Engineered structured (ES) sorbents are being developed to meet the technical challenges of future crewed space exploration missions. ES sorbents offer the inherent performance and safety attributes of zeolite and other physical adsorbents but with greater structural integrity and process control to improve durability and efficiency over packed beds. ES sorbent techniques that are explored include thermally linked and pressure-swing adsorption beds for water-save dehumidification and sorbent-coated metal meshes for residual drying, trace contaminant control, and carbon dioxide control. Results from sub-scale performance evaluations of a thermally linked pressure-swing adsorbent bed and an integrated sub-scale ES sorbent system are discussed.

  19. Monitoring by Control Technique - Activated Carbon Adsorber

    EPA Pesticide Factsheets

    Stationary source emissions monitoring is required to demonstrate that a source is meeting the requirements in Federal or state rules. This page is about Activated Carbon Adsorber control techniques used to reduce pollutant emissions.

  20. Desorption kinetics of benzene in a sandy soil in the presence of powdered activated carbon.

    PubMed

    Choi, J-W; Kim, S-B; Kim, D-J

    2007-02-01

    Desorption kinetics of benzene was investigated with a modified biphasic desorption model in a sandy soil with five different powdered activated carbon (PAC) contents (0, 1, 2, 5, 10% w/w) as sorbents. Sorption experiments followed by series dilution desorption were conducted for each sorbent. Desorption of benzene was successively performed at two stages using deionized water and hexane. Modeling was performed on both desorption isotherm and desorption rate for water-induced desorption to elucidate the presence of sorption-desorption hysteresis and biphasic desorption and if present to quantify the desorption-resistant fraction (q (irr)) and labile fraction (F) of desorption site responsible for rapid process. Desorption isotherms revealed that sorption-desorption exhibited a severe hysteresis with a significant fraction of benzene being irreversibly adsorbed onto both pure sand and PAC, and that desorption-resistant fraction (q (irr)) increased with PAC content. Desorption kinetic modeling showed that desorption of benzene was biphasic with much higher (4-40 times) rate constant for rapid process (k (1)) than that for slow process (k (2)), and that the difference in the rate constant increased with PAC content. The labile fraction (F) of desorption site showed a decreasing tendency with PAC. The experimental results would provide valuable information on remediation methods for soils and groundwater contaminated with BTEX.

  1. Comparative performance of cement kiln dust and activated carbon in removal of cadmium from aqueous solutions.

    PubMed

    El-Refaey, Ahmed A

    2016-01-01

    This study compared the performance of cement kiln dust (CKD) as industrial byproduct and commercially activated carbon (AC) as adsorbent derived from agricultural waste for the removal of cadmium (Cd(2+)) from aqueous solutions. CKD and AC were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) and surface areas demonstrate the differences of physicochemical properties. Batch equilibrium experiments were conducted for various intervals extended to 96 h at 20, 25 and 30°C to investigate the efficiency of the sorbents in the removal of Cd(2+). CKD expressed high affinity for removal of Cd(2+) and was not affected by temperature, while AC was significantly affected, which reflects dissimilarity in the retention mechanisms defendant in CKD and those pursued by AC. The results were explained by changes of FTIR and SEM images before and after sorption experiments. The suggestion is that electrostatic ion exchange and complex reactions are the main mechanisms for Cd(2+) removal. The kinetic data were evaluated by fractional power, Elovich, pseudo-first order and pseudo-second-order kinetic models. The pseudo-second-order kinetic model was found to correlate with the experimental data well. These results revealed that CKD can be used as a cost-effective and efficient sorbent for Cd(2+) removal in comparison with AC.

  2. Thermal removal of mercury in spent powdered activated carbon from TOXECON process

    SciTech Connect

    Okwadha, G.D.O.; Li, J.; Ramme, B.; Kollakowsky, D.; Michaud, D.

    2009-10-15

    This research developed and demonstrated a technology to liberate Hg adsorbed onto powdered activated carbon (PAC) by the TOXECON process using pilot-scale high temperature air slide (HTAS) and bench-scale thermogravimetric analyzer (TGA). The HTAS removed 65, 83, and 92% of Hg captured with PAC when ran at 900{sup o}F, 1,000{sup o}F, and 1,200 {sup o}F, respectively, while the TGA removed 46 and 100% of Hg at 800 {sup o}F and 900{sup o}F, respectively. However, addition of CuO-Fe{sub 2}O{sub 3} mixture and CuCl catalysts enhanced Hg removal and PAC regeneration at lower temperatures. CuO-Fe{sub 2}O{sub 3} mixture performed better than CuCl in PAC regeneration. Scanning electron microscopy images and energy dispersive X-ray analysis show no change in PAC particle aggregation or chemical composition. Thermally treated sorbents had higher surface area and pore volume than the untreated samples indicating regeneration. The optimum temperature for PAC regeneration in the HTAS was 1,000{sup o}F. At this temperature, the regenerated sorbent had sufficient adsorption capacity similar to its virgin counterpart at 33.9% loss on ignition. Consequently, the regenerated PAC may be recycled back into the system by blending it with virgin PAC.

  3. JV Task 119 - Effects of Aging on Treated Activated Carbons

    SciTech Connect

    Edwin Olson; Lucinda Hamre; John Pavlish; Blaise Mibeck

    2009-03-25

    For both the United States and Canada, testing has been under way for electric utilities to find viable and economical mercury control strategies to meet pending future mercury emission limits. The technology that holds the most promise for mercury control in low-chlorine lignite to meet the needs of the Clean Air Act in the United States and the Canada-Wide Standards in Canada is injection of treated activated carbon (AC) into the flue gas stream. Most of the treated carbons are reported to be halogenated, often with bromine. Under a previous multiyear project headed by the Energy & Environmental Research Center (EERC), testing was performed on a slipstream unit using actual lignite-derived flue gas to evaluate various sorbent technologies for their effectiveness, performance, and cost. Testing under this project showed that halogenated ACs performed very well, with mercury capture rates often {ge} 90%. However, differences were noted between treated ACs with respect to reactivity and capacity, possibly as a result of storage conditions. Under certain conditions (primarily storage in ambient air), notable performance degradation had occurred in mercury capture efficiency. Therefore, a small exploratory task within this project evaluated possible differences resulting from storage conditions and subsequent effects of aging that might somehow alter their chemical or physical properties. In order to further investigate this potential degradation of treated (halogenated) ACs, the EERC, together with DOE's National Energy Technology Laboratory, the North Dakota Industrial Commission (NDIC), the Electric Power Research Institute (EPRI), SaskPower, and Otter Tail Power Company, assessed the aging effects of brominated ACs for the effect that different storage durations, temperatures, and humidity conditions have on the mercury sorption capacity of treated ACs. No aging effects on initial capture activity were observed for any carbons or conditions in the investigation

  4. Process for preparing zinc oxide-based sorbents

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2011-06-07

    The disclosure relates to zinc oxide-based sorbents, and processes for preparing and using them. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  5. Developing a Small-scale De-fluoridation Filter for use in Rural Northern Ghana with Activated Alumina as the Sorbent

    NASA Astrophysics Data System (ADS)

    Craig, L.; Stillings, L. L.; Decker, D.; Thomas, J.

    2013-12-01

    In northern Ghana, groundwater is the main source of household water and is generally considered a safe and economical source of drinking water. However in some areas it contains fluoride (F-) concentrations above the 1.5 ppm limit recommended by the World Health Organization, putting the users at risk of fluorosis. The study area in the Upper East Region of northern Ghana has pockets of groundwater F- up to 4.6 ppm and, as a result, also has a high percentage of residents with dental fluorosis. They have no alternative water source and, because of the poverty and limited access to technology, the affected community lacks the capacity to set up advanced treatment systems. One proposed solution is to attach F- adsorption filters to the wells, since adsorption is considered a simple and cost effective approach for treating high F- drinking water. This study evaluates activated alumina as a sorbent for use in de-fluoridation filters in the study area. We evaluated the long-term adsorption capacity of activated alumina, as well as potential changes in F- adsorption rate and capacity with grain size. We measured differences in positive surface charge (as C m-2) via slow acid titration, as well as F- loading with varied prior hydration time. Experimental results from this research show no notable change in F- adsorption or positive surface charge when the activated alumina surface was pre-equilibrated in distilled water from 24 hours up to 30 weeks before the experiment. The results of F- loading show a maximum of ~3.4 mg F- sorbed per gm activated alumina (at initial pH ~6.9, initial F- 1 to 60 ppm, and 20 hr reaction time). The pH dependent surface charge shows a maximum of ~0.14 C m-2 at pH of ~4.4 and zero surface charge at pH ~8.5. F- loading experiments were conducted with grain size ranges 0.125 to 0.250 mm and 0.5 to 1.0 mm to evaluate changes in F- adsorption rate (initial pH ~6.9, initial F- 10 ppm) and F- loading (initial pH ~6.9, initial F- 1 to 60 ppm, 20 hr

  6. Hyrdothermally prepared biochars from potato peels. Activation of biochars with phosphoric acid for use as sorbents for cobalt removal from wastewaters

    NASA Astrophysics Data System (ADS)

    Lakkovikiotis, Evangelos; Kyzas, George; Deliyanni, Eleni; Matis, Kostas

    2014-05-01

    In the present study, activated carbons (ACs) were hydrothermally prepared with an environmental friendly preparation route from biomass (specifically from potato peels). The prepared biochars were activated with phosphoric acid (chemical activation). The porous texture and the surface chemistry of the biochars and the relative activated carbons prepared were investigated and were compared to the activated carbon prepared and activated by pyrolysis, in one step procedure. Biochars and activated carbon materials were also characterized by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. The prepared activated carbons were used as adsorbents for the removal of cobalt from aqueous solutions. Batch experiments were performed to investigate the effect of physico-chemical parameters, such as pH, adsorbent dose, contact time, initial metal concentration and temperature. The kinetics of adsorption were studied by applying the pseudo-first order, pseudo-second order and intraparticle diffusion models. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The thermodynamic parameters such as the change of enthalpy (ΔH0), entropy (ΔS0) and Gibb's free energy (ΔG0) of adsorption systems were also determined and evaluated.

  7. Sorbent preparation/modification/additives. Final report, September 1, 1992--November 30, 1993

    SciTech Connect

    Prudich, M.E.; Venkataramakrishnan, R.

    1994-02-01

    Sorbent preparation techniques used today have generally been adapted from techniques traditionally used by the lime industry. Traditional dry hydration and slaking processes have been optimized to produce materials intended for use in the building industry. These preparation techniques should be examined with an eye to optimization of properties important to the SO{sub 2} capture process. The study of calcium-based sorbents for sulfur dioxide capture is complicated by two factors: (1) little is known about the chemical mechanisms by which the standard sorbent preparation and enhancement techniques work, and (2) a sorbent preparation technique that produces a calcium-based sorbent that enjoys enhanced calcium utilization in one regime of operation [flame zone (>2400 F), in-furnace (1600--2400 F), economizer (800--1100 F), after air preheater (<350 F)] may not produce a sorbent that enjoys enhanced calcium utilization in the other reaction zones. Again, an in-depth understanding of the mechanism of sorbent enhancement is necessary if a systematic approach to sorbent development is to be used. As a long-term goal, an experimental program is being carried out for the purpose of (1) defining the effects of slaking conditions on the properties of calcium-based sorbents, (2) determining how the parent limestone properties of calcium-based sorbents, and (3) elucidating the mechanism(s) relating to the activity of various dry sorbent additives. An appendix contains a one-dimensional duct injection model with modifications to handle the sodium additives.

  8. Developing a Small-Scale De-Fluoridation Filter for Use in Rural Northern Ghana with Activated Alumina As the Sorbent

    NASA Astrophysics Data System (ADS)

    Craig, L.; Stillings, L. L.

    2014-12-01

    In northern Ghana, groundwater is the main source of household water and is generally considered safe to drink. However in some areas it contains fluoride (F-) concentrations above the 1.5 ppm limit recommended by the World Health Organization, putting the users at risk of fluorosis. The study area in the Upper East Region of Ghana has pockets of groundwater F- up to 4.6 ppm and, as a result, also has a high percentage of residents with dental fluorosis. They have no alternative water source and, because of poverty and limited access to technology, lack the capacity to set up advanced treatment systems. One proposed solution is to attach F- adsorption filters to the wells, since adsorption is considered a simple and cost effective approach for treating high F-drinking water. This study evaluates activated alumina as a sorbent for use in de-fluoridation filters in the study area. We evaluated the long-term adsorption capacity of activated alumina, and changes in F- adsorption rate and capacity with grain size. We measured differences in positive surface charge (C m-2) via slow acid titration, as well as F- loading with varied prior hydration time. Results from this research show no notable change in F- adsorption or positive surface charge when the activated alumina surface was pre-equilibrated in distilled water from 24 hours to 30 weeks. The results of F- loading show a maximum of ~3.4 mg F- sorbed per gm activated alumina (initial pH ~6.9, initial F- 1 to 60 ppm, 20 hr reaction time). The pH dependent surface charge is ~0.14 C m-2 at pH of ~4.4 and is zero at pH ~8.6. F- loading experiments were conducted with grain size 0.125 to 0.250 mm and 0.5 to 1.0 mm to evaluate changes in F- adsorption rate (initial pH ~6.9, initial F- 10 ppm) and F- loading (initial pH ~6.9, initial F- 1 to 60 ppm, 20 hr reaction time). The F- loading did not change with grain size. However time to equilibrium increased dramatically with a decrease in grain size - after one hour of

  9. Antimicrobial Activity of Carbon-Based Nanoparticles

    PubMed Central

    Maleki Dizaj, Solmaz; Mennati, Afsaneh; Jafari, Samira; Khezri, Khadejeh; Adibkia, Khosro

    2015-01-01

    Due to the vast and inappropriate use of the antibiotics, microorganisms have begun to develop resistance to the commonly used antimicrobial agents. So therefore, development of the new and effective antimicrobial agents seems to be necessary. According to some recent reports, carbon-based nanomaterials such as fullerenes, carbon nanotubes (CNTs) (especially single-walled carbon nanotubes (SWCNTs)) and graphene oxide (GO) nanoparticles show potent antimicrobial properties. In present review, we have briefly summarized the antimicrobial activity of carbon-based nanoparticles together with their mechanism of action. Reviewed literature show that the size of carbon nanoparticles plays an important role in the inactivation of the microorganisms. As major mechanism, direct contact of microorganisms with carbon nanostructures seriously affects their cellular membrane integrity, metabolic processes and morphology. The antimicrobial activity of carbon-based nanostructures may interestingly be investigated in the near future owing to their high surface/volume ratio, large inner volume and other unique chemical and physical properties. In addition, application of functionalized carbon nanomaterials as carriers for the ordinary antibiotics possibly will decrease the associated resistance, enhance their bioavailability and provide their targeted delivery. PMID:25789215

  10. Comparison of activated carbon and oxidized multiwalled carbon nanotubes modified with bis(3-nitrobenzylidene)-1,2-ethanediamine for enrichment of trace amounts of some metal ions.

    PubMed

    Ghaedi, Mehrorang; Montazerozohori, Mortaza; Tabatabie, Maryam; Noormohamadi, Hamid; Haghighi, Alireza Borhan

    2012-01-01

    The efficiency of modified activated carbon (AC) and multiwalled carbon nanotubes (MWCNTs) for the separation/preconcentration and determination of Co, Cd, Pb, Zn, and Cu following their complexation by bis(3-nitrobenzylidene)-1,2-ethanediamine has been described and compared. A one-at-a-time optimization method investigated the influence of various parameters that significantly influence the recoveries of the studied metal ions. At the optimum values of all variables, the response was linear over the range of 0.01-0.3 microg/mL, and detection limit (3 SDb/m, n = 10) was between 1.41-2.05 ng/mL for both sorbents while the preconcentration factor was 100 for AC and 500 for MWCNTs. The method was successfully applied for preconcentration and determination of trace amount of the aforementioned ions in various real samples such as orange, lettuce, bread, and pear.

  11. Sorption of lanthanum and erbium from aqueous solution by activated carbon prepared from rice husk.

    PubMed

    Awwad, N S; Gad, H M H; Ahmad, M I; Aly, H F

    2010-12-01

    A biomass agricultural waste material, rice husk (RH) was used for preparation of activated carbon by chemical activation using phosphoric acid. The effect of various factors, e.g. time, pH, initial concentration and temperature of carbon on the adsorption capacity of lanthanum and erbium was quantitatively determined. It was found that the monolayer capacity is 175.4 mg g(-1) for La(III) and 250 mg g(-1) for Er(III). The calculated activation energy of La(III) adsorption on the activated carbon derived from rice husk was equal to 5.84 kJ/mol while it was 3.6 kJ/mol for Er(III), which confirm that the reaction is mainly particle-diffusion-controlled. The kinetics of sorption was described by a model of a pseudo-second-order. External diffusion and intra-particular diffusion were examined. The experimental data show that the external diffusion and intra-particular diffusion are significant in the determination of the sorption rate. Therefore, the developed sorbent is considered as a better replacement technology for removal of La(III) and Er(III) ions from aqueous solution due to its low-cost and good efficiency, fast kinetics, as well as easy to handle and thus no or small amount of secondary sludge is obtained in this application.

  12. Development of activated carbon derived from banana peel for CO{sub 2} removal

    SciTech Connect

    Borhan, Azry; Thangamuthu, Subhashini; Ramdan, Amira Nurain; Taha, Mohd Faisal

    2015-08-28

    This research work highlights on the constraints involved in the preparation of the banana peel bio-sorbent, such as impregnation ratio, activation temperature and period of activation for reducing carbon dioxide (CO{sub 2}) in the atmosphere. Micromeritics ASAP 2020 and Field Emission Scanning Electron Microscope (FESEM) were used in identifying the best sample preparation method with the largest surface area which directly contributes to the effectiveness of adsorbent in removing CO{sub 2}. Sample A10 was identified to yield activated carbon with the largest surface area (260.3841 m{sup 2}/g), total pore volume (0.01638 cm{sup 3}/g) and pore diameter (0.2508 nm). Through nitrogen adsorption-desorption isotherm analysis, the existence of sub-micropores was proven when a combination of Type-I and Type-II isotherms were exhibited by the activated carbon produced. The results from the final adsorption test found that the material synthesized from the above mentioned parameter is capable of removing up to 1.65% wt of CO{sub 2} through adsorption at 25°C, suggesting that it can be effectively used as an adsorption material.

  13. Adsorption behavior of alpha -cypermethrin on cork and activated carbon.

    PubMed

    Domingues, Valentina F; Priolo, Giuseppe; Alves, Arminda C; Cabral, Miguel F; Delerue-Matos, Cristina

    2007-08-01

    Studies were undertaken to determine the adsorption behavior of alpha -cypermethrin [R)-alpha -cyano-3-phenoxybenzyl(1S)-cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate, and (S)-alpha-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate] in solutions on granules of cork and activated carbon (GAC). The adsorption studies were carried out using a batch equilibrium technique. A gas chromatograph with an electron capture detector (GC-ECD) was used to analyze alpha -cypermethrin after solid phase extraction with C18 disks. Physical properties including real density, pore volume, surface area and pore diameter of cork were evaluated by mercury porosimetry. Characterization of cork particles showed variations thereby indicating the highly heterogeneous structure of the material. The average surface area of cork particles was lower than that of GAC. Kinetics adsorption studies allowed the determination of the equilibrium time - 24 hours for both cork (1-2 mm and 3-4 mm) and GAC. For the studied alpha -cypermethrin concentration range, GAC revealed to be a better sorbent. However, adsorption parameters for equilibrium concentrations, obtained through the Langmuir and Freundlich models, showed that granulated cork 1-2 mm have the maximum amount of adsorbed alpha-cypermethrin (q(m)) (303 microg/g); followed by GAC (186 microg/g) and cork 3-4 mm (136 microg/g). The standard deviation (SD) values, demonstrate that Freundlich model better describes the alpha -cypermethrin adsorption phenomena on GAC, while alpha -cypermethrin adsorption on cork (1-2 mm and 3-4 mm) is better described by the Langmuir. In view of the adsorption results obtained in this study it appears that granulated cork may be a better and a cheaper alternative to GAC for removing alpha -cypermethrin from water.

  14. Laboratory scale studies of Pd/y-Al2O3 sorbents for the removal of trace contaminents from coal-derived fuel gas at elevated temperatures

    SciTech Connect

    Rupp, Erik C.; Granite, Evan J.; Stanko, Dennis C.

    2010-12-31

    The Integrated Gasification Combined Cycle (IGCC) is a promising technology for the use of coal in a clean and efficient manner. In order to maintain the overall efficiency of the IGCC process, it is necessary to clean the fuel gas of contaminants (sulfur, trace compounds) at warm (150-540 C) to hot (>540 C) temperatures. Current technologies for trace contaminant (such as mercury) removal, primarily activated carbon based sorbents, begin to lose effectiveness above 100 C, creating the need to develop sorbents effective at elevated temperatures. As trace elements are of particular environmental concern, previous work by this group has focused on the development of a Pd/{gamma}-Al{sub 2}O{sub 3} sorbent for Hg removal. This paper extends the research to Se (as hydrogen selenide, H{sub 2}Se), As (as arsine, AsH{sub 3}), and P (as phosphine, PH{sub 3}) which thermodynamic studies indicate are present as gaseous species under gasification conditions. Experiments performed under ambient conditions in He on 20 wt.% Pd/{gamma}-Al{sub 2}O{sub 3} indicate the sorbent can remove the target contaminants. Further work is performed using a 5 wt.% Pd/{gamma}-Al{sub 2}O{sub 3} sorbent in a simulated fuel gas (H{sub 2}, CO, CO{sub 2}, N{sub 2} and H{sub 2}S) in both single and multiple contaminant atmospheres to gauge sorbent performance characteristics. The impact of H{sub 2}O, Hg and temperature on sorbent performance is explored.

  15. Activated coconut shell charcoal carbon using chemical-physical activation

    NASA Astrophysics Data System (ADS)

    Budi, Esmar; Umiatin, Nasbey, Hadi; Bintoro, Ridho Akbar; Wulandari, Futri; Erlina

    2016-02-01

    The use of activated carbon from natural material such as coconut shell charcoal as metal absorbance of the wastewater is a new trend. The activation of coconut shell charcoal carbon by using chemical-physical activation has been investigated. Coconut shell was pyrolized in kiln at temperature about 75 - 150 °C for about 6 hours in producing charcoal. The charcoal as the sample was shieved into milimeter sized granule particle and chemically activated by immersing in various concentration of HCl, H3PO4, KOH and NaOH solutions. The samples then was physically activated using horizontal furnace at 400°C for 1 hours in argon gas environment with flow rate of 200 kg/m3. The surface morphology and carbon content of activated carbon were characterized by using SEM/EDS. The result shows that the pores of activated carbon are openned wider as the chemical activator concentration is increased due to an excessive chemical attack. However, the pores tend to be closed as further increasing in chemical activator concentration due to carbon collapsing.

  16. Thermodynamic and kinetic behaviors of trinitrotoluene adsorption on powdered activated carbons

    SciTech Connect

    Lee, J.W.; Hwang, K.J.; Shim, W.G.; Moon, I.S.

    2006-07-01

    Regulations on the removal of trinitrotoluene (TNT) from wastewater have become increasingly more stringent, demanding faster, less expensive, and more efficient treatment. This study focuses on the adsorption equilibrium and kinetics of TNT on powered activated carbons (PAC). Three types of PACs (i.e., wood based, coal based, and coconut-shell based) were studied as functions of temperature and pH. Thermodynamic properties including Gibbs free energy, enthalpy, and entropy, were evaluated by applying the Van't Hoff equation. In addition, the adsorption energy distribution functions which describe heterogeneous characteristics of porous solid sorbents were calculated by using the generalized nonlinear regularization method. Adsorption kinetic studies were carried out in batch adsorber under important conditions such as PAC types, temperature, pH, and concentration. We found that fast and efficient removal of TNT dissolved in water can be successfully achieved by PAC adsorption.

  17. Development of a Rapid Cycling CO(sub 2) and H(sub 2)O Removal Sorbent

    NASA Technical Reports Server (NTRS)

    Paul, Heather; Alptekin, Goekhan; Cates, Matthew; Bernal, Casey; Dubovik, Margarita; Gershanovich, Yevgenia

    2007-01-01

    The National Aeronautics and Space Administration (NASA) planned future missions set stringent demands on the design of the Portable Life Support System (PLSS), requiring dramatic reductions in weight, decreased reliance on supplies and greater flexibility on the types of missions. Use of regenerable systems that reduce weight and volume of the Extravehicular Mobility Unit (EMU) is of critical importance to NASA, both for low orbit operations and for long duration manned missions. The carbon dioxide and humidity control unit in the existing PLSS design is relatively large, since it has to remove and store 8 hours worth of CO2. If the sorbent regeneration can be carried out during the extravehicular activity (EVA) with a relatively high regeneration frequency, the size of the sorbent canister and weight can be significantly reduced. The progress of regenerable CO2 and humidity control is leading us towards the use of a rapid cycling amine system. TDA Research, Inc. is developing compact, regenerable sorbent materials to control CO2 and humidity in the space suit ventilation loop. The sorbent can be regenerated using space vacuum during the EVA, eliminating all carbon dioxide and humidity duration-limiting elements in the life support system. The material also has applications in other areas of space exploration such as the Orion spacecraft and other longer duration exploration missions requiring regenerable technologies. This paper summarizes the results of the sorbent development, testing, and evaluation efforts to date. The results of a preliminary system analysis are also included, showing the size and volume reductions for PLSS provided by the new system.

  18. Converting Poultry Litter into Activated Carbon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disposal of animal manure is one of the biggest problems facing agriculture today. Now new technology has been designed to covert manure into environmentally friendly and highly valued activated carbon. When pelletized and activated under specific conditions, the litter becomes a highly porous mat...

  19. Deposition of Magnetite Nanoparticles in Activated Carbons and Preparation of Magnetic Activated Carbons

    NASA Astrophysics Data System (ADS)

    Kahani, S. A.; Hamadanian, M.; Vandadi, O.

    2007-08-01

    Magnetic activated carbons (MACs) for gold recovery from alkaline cyanide solutions have been developed by mixing a magnetic precursor with a carbon source, and treating the mixture under controlled conditions. As would be expected, these activated carbons have high specific surface areas due to their microporous structure. In addition, the small particle size of the MACs produced allows rapid adsorption of gold in solution, and the magnetic character of these MACs enables recovery from suspension by magnetic separation.

  20. Phenanthrene and pyrene sorption and intraparticle diffusion in polyoxymethylene, coke, and activated carbon

    SciTech Connect

    Sungwoo Ahn; David Werner; Hrissi K. Karapanagioti; Donald R. McGlothlin; Richard N. Zare; Richard G. Luthy

    2005-09-01

    The authors report sorption isotherms and uptake kinetics for phenanthrene and pyrene with three organic model sorbents: polyoxymethylene (POM), coke breeze, and activated carbon. Batch equilibration and kinetic experiments were combined with the direct observation of the long-term diffusion of phenanthrene and pyrene as measured within cross-sectioned particles using microprobe laser-desorption laser-ionization mass spectroscopy ({mu}L{sup 2}MS). For POM pellets, the intraparticle concentration profiles predicted from kinetic batch experiments and a polymer diffusion model with spherical geometry are in agreement with the independent {mu}L{sup 2}MS measurements. For coke particles, the apparent diffusivities decreased with smaller particle size. These trends in diffusivities were described by a sorption-retarded pore diffusion model with a particle-size-dependent solid-water partitioning coefficient obtained from apparent equilibrium observed in the kinetic batch studies. For activated carbon, the {mu}L{sup 2}MS measurements showed faster radial diffusion of phenanthrene and pyrene into the particle interior than predicted from diffusion models based on a single sorption domain and diffusivity. A branched pore kinetic model, comprising polycyclic aromatic hydrocarbon (PAH) macropore diffusion with kinetic exchange of PAH between macroporous and microporous domains, fits the experimental observations better. It is not possible to make independent parameter estimations for intraparticle diffusion in activated carbon using present procedures. 41 refs., 4 figs., 3 tabs.

  1. Phenanthrene and pyrene sorption and intraparticle diffusion in polyoxymethylene, coke, and activated carbon.

    PubMed

    Ahn, Sungwoo; Werner, David; Karapanagioti, Hrissi K; McGlothlin, Donald R; Zare, Richard N; Luthy, Richard G

    2005-09-01

    We report sorption isotherms and uptake kinetics for phenanthrene and pyrene with three organic model sorbents: polyoxymethylene (POM), coke, and activated carbon. We combine batch equilibration and kinetic experiments with the direct observation of the long-term diffusion of phenanthrene and pyrene as measured within cross-sectioned particles using microprobe laser-desorption laser-ionization mass spectroscopy (muL2MS). For POM pellets, the intraparticle concentration profiles predicted from kinetic batch experiments and a polymer diffusion model with spherical geometry are in agreement with the independent muL2MS measurements. For coke particles, the apparent diffusivities decreased with smaller particle size. These trends in diffusivities were described by a sorption-retarded pore diffusion model with a particle-size-dependent solid-water partitioning coefficient obtained from apparent equilibrium observed in the kinetic batch studies. For activated carbon, the muL2MS measurements showed faster radial diffusion of phenanthrene and pyrene into the particle interior than predicted from diffusion models based on a single sorption domain and diffusivity. A branched pore kinetic model, comprising polycyclic aromatic hydrocarbon (PAH) macropore diffusion with kinetic exchange of PAH between macroporous and microporous domains, fits the experimental observations better. Because of parallel macro- and microdiffusion processes, nonlinear sorption isotherms, and a concentration-dependent diffusivity, it is not possible to make independent parameter estimations for intraparticle diffusion in activated carbon using our present procedures.

  2. Storage stability of ketones on carbon adsorbents.

    PubMed

    Prado, C; Alcaraz, M J; Fuentes, A; Garrido, J; Periago, J F

    2006-09-29

    Activated coconut carbon constitutes the more widely used sorbent for preconcentration of volatile organic compounds in sampling workplace air. Water vapour is always present in the air and its adsorption on the activated carbon surface is a serious drawback, mainly when sampling polar organic compounds, such as ketones. In this case, the recovery of the compounds diminishes; moreover, ketones can be decomposed during storage. Synthetic carbons contain less inorganic impurities and have a lower capacity for water adsorption than coconut charcoal. The aim of this work was to evaluate the storage stability of various ketones (acetone, 2-butanone, 4-methyl-2-pentanone and cyclohexanone) on different activated carbons and to study the effect of adsorbed water vapour under different storage conditions. The effect of storage temperature on extraction efficiencies was significant for each ketone in all the studied sorbents. Recovery was higher when samples were stored at 4 degrees C. The results obtained for storage stability of the studied ketones showed that the performance of synthetic carbons was better than for the coconut charcoals. The water adsorption and the ash content of the carbons can be a measure of the reactive sites that may chemisorb ketones or catalize their decomposition. Anasorb 747 showed good ketone stability at least for 7 days, except for cyclohexanone. After 30-days storage, the stability of the studied ketones was excellent on Carboxen 564. This sorbent had a nearly negligible ash content and the adsorbed water was much lower than for the other sorbents tested.

  3. Selection of pecan shell-based activated carbons for removal of organic and inorganic impurities from water.

    PubMed

    Niandou, Mohamed A S; Novak, Jeffrey M; Bansode, Rishipal R; Yu, Jianmei; Rehrah, Djaafar; Ahmedna, Mohamed

    2013-01-01

    Activated carbons are a byproduct from pyrolysis and have value as a purifying agent. The effectiveness of activated carbons is dependent on feedstock selection and pyrolysis conditions that modify their surface properties. Therefore, pecan shell-based activated carbons (PSACs) were prepared by soaking shells in 50% (v/v) HPO or 25 to 50% of KOH-NaHCO followed by pyrolysis at 400 to 700°C under a N atmosphere. Physically activated PSACs were produced by pyrolysis at 700°C under N followed by activation with steam or CO at 700 to 900°C. Physicochemical, surface, and adsorption properties of the PSACs were compared with two commercially available activated carbons. The average mass yield of PSACs with respect to the initial mass of the biomass was about 20 and 34% for physically activated and chemically activated carbons, respectively. Acid-activated carbons exhibited higher surface area, higher bulk density, and lower ash content compared with steam- or CO-activated carbons and the two commercial products. Base activation led to the development of biochar with moderate to high surface area with surface charges suitable for adsorption of anionic species. Regardless of the activation method, PSACs had high total surface area ranging from 400 to 1000 m g, better pore size distribution, and more surface charges than commercial samples. Our results also showed that PSACs were effective in removing inorganic contaminants such as Cu and NO as well as organic contaminants such as atrazine and metolachlor. This study showed that pyrolysis conditions and activation had a large influence on the PSAC's surface characteristics, which can limit its effectiveness as a custom sorbent for targeted water contaminants.

  4. Enhanced durability of desulfurization sorbents for fluidized-bed applications

    SciTech Connect

    Gupta, R.P.; Gangwal, S.K.

    1993-08-01

    To the most important findings of this 100-cycle test, ZT-4 consistently reduced the H{sub 2}S content of coal gas from 11,400 ppmv to less than 20 ppmv at 750{degree}C. The sorbent exhibited deactivation over 100 cycles with most of the activity decline occurring in the first 50 cycles. This deactivation was found to correlate with decreases in the BET area, pore volume, and internal porosity. The best correlation, as expected with small particles, was with the BET surface area. Formation of zinc silicate in the sorbent structure is believed to be a potential cause of deactivation. Despite deactivation, the sorbent became more attrition-resistant after 100 cycles of testing with negligible material loss from the reactor. No evidence of zinc loss from the sorbent was found despite its operation at 750{degree}C for 100 cycles.

  5. Metal sulfide initiators for metal oxide sorbent regeneration

    DOEpatents

    Turk, Brian S.; Gupta, Raghubir P.

    2001-01-01

    A process of regenerating a sulfided sorbent is provided. According to the process of the invention, a substantial portion of the energy necessary to initiate the regeneration reaction is provided by the combustion of a particulate metal sulfide additive. In using the particulate metal sulfide additive, the oxygen-containing gas used to regenerate the sulfided sorbent can be fed to the regeneration zone without heating or at a lower temperature than used in conventional processes wherein the regeneration reaction is initiated only by heating the oxygen-containing gas. The particulate metal sulfide additive is preferably an inexpensive mineral ore such as iron pyrite which does not adversely affect the regeneration or corresponding desulfurization reactions. The invention further includes a sorbent composition comprising the particulate metal sulfide additive in admixture with an active metal oxide sorbent capable of removing one or more sulfur compounds from a sulfur-containing gas stream.

  6. Metal sulfide initiators for metal oxide sorbent regeneration

    DOEpatents

    Turk, Brian S.; Gupta, Raghubir P.

    1999-01-01

    A process of regenerating a sulfided sorbent is provided. According to the process of the invention, a substantial portion of the energy necessary to initiate the regeneration reaction is provided by the combustion of a particulate metal sulfide additive. In using the particulate metal sulfide additive, the oxygen-containing gas used to regenerate the sulfided sorbent can be fed to the regeneration zone without heating or at a lower temperature than used in conventional processes wherein the regeneration reaction is initiated only by heating the oxygen-containing. The particulate metal sulfide additive is preferably an inexpensive mineral ore such as iron pyrite which does not adversely affect the regeneration or corresponding desulfurization reactions. The invention further includes a sorbent composition comprising the particulate metal sulfide additive in admixture with an active metal oxide sorbent capable of removing one or more sulfur compounds from a sulfur-containing gas stream.

  7. Metal sulfide initiators for metal oxide sorbent regeneration

    DOEpatents

    Turk, B.S.; Gupta, R.P.

    1999-06-22

    A process of regenerating a sulfided sorbent is provided. According to the process of the invention, a substantial portion of the energy necessary to initiate the regeneration reaction is provided by the combustion of a particulate metal sulfide additive. In using the particulate metal sulfide additive, the oxygen-containing gas used to regenerate the sulfided sorbent can be fed to the regeneration zone without heating or at a lower temperature than used in conventional processes wherein the regeneration reaction is initiated only by heating the oxygen-containing gas. The particulate metal sulfide additive is preferably an inexpensive mineral ore such as iron pyrite which does not adversely affect the regeneration or corresponding desulfurization reactions. The invention further includes a sorbent composition comprising the particulate metal sulfide additive in admixture with an active metal oxide sorbent capable of removing one or more sulfur compounds from a sulfur-containing gas stream. 1 fig.

  8. Novel Sorbent to Clean Up Biogas for CHPs

    SciTech Connect

    Alptekin, Gökhan O.; Jayataman, Ambalavanan; Schaefer, Matthew; Ware, Michael; Hunt, Jennifer; Dobek, Frank

    2015-05-30

    In this project, TDA Research Inc. (TDA) has developed low-cost (on a per unit volume of gas processed basis), high-capacity expendable sorbents that can remove both the H2S and organic sulfur species in biogas to the ppb levels. The proposed sorbents will operate downstream of a bulk desulfurization system as a polishing bed to provide an essentially sulfur-free gas to a fuel cell (or any other application that needs a completely sulfur-free feed). Our sorbents use a highly dispersed mixed metal oxides active phase with desired modifiers prepared over on a mesoporous support. The support structure allows the large organic sulfur compounds (such as the diethyl sulfide and dipropyl sulfide phases with a large kinetic diameter) to enter the sorbent pores so that they can be adsorbed and removed from the gas stream.

  9. Removal of arsenic from water by supported nano zero-valent iron on activated carbon.

    PubMed

    Zhu, Huijie; Jia, Yongfeng; Wu, Xing; Wang, He

    2009-12-30

    Nano-sized zero-valent iron is an effective adsorbent for arsenic removal from drinking water. However, its application may be limited in public water system and small scale water treatment system due to its tiny particle size. In the present work, nanoscale zero-valent iron was supported onto activated carbon (NZVI/AC) by impregnating carbon with ferrous sulfate followed by chemical reduction with NaBH(4). Approximate 8.2 wt% of iron was loaded onto carbon and SEM analysis showed that the iron particles in the pores of carbon were needle-shaped with the size of 30-500 x 1000-2000 nm. Kinetics study revealed that adsorption of arsenite and arsenate by NZVI/AC was fast in the first 12h and the equilibrium was achieved in approximately 72 h. The adsorption capacity of the synthesized sorbent for arsenite and arsenate at pH 6.5 calculated from Langmuir adsorption isotherms in batch experiments was 18.2 and 12.0mg/g, respectively. Phosphate and silicate markedly decreased the removal of both arsenite and arsenate, while the effect of other anions and humic acid was insignificant. Common metal cations (Ca(2+), Mg(2+)) enhanced arsenate adsorption but ferrous iron (Fe(2+)) was found to suppress arsenite adsorption. NZVI/AC can be effectively regenerated by elution with 0.1M NaOH.

  10. A novel activated carbon for supercapacitors

    SciTech Connect

    Shen, Haijie; Liu, Enhui; Xiang, Xiaoxia; Huang, Zhengzheng; Tian, Yingying; Wu, Yuhu; Wu, Zhilian; Xie, Hui

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer A novel activated carbon was prepared from phenol-melamine-formaldehyde resin. Black-Right-Pointing-Pointer The carbon has large surface area with microporous, and high heteroatom content. Black-Right-Pointing-Pointer Heteroatom-containing functional groups can improve the pseudo-capacitance. Black-Right-Pointing-Pointer Physical and chemical properties lead to the good electrochemical properties. -- Abstract: A novel activated carbon has been prepared by simple carbonization and activation of phenol-melamine-formaldehyde resin which is synthesized by the condensation polymerization method. The morphology, thermal stability, surface area, elemental composition and surface chemical composition of samples have been investigated by scanning electron microscope, thermogravimetry and differential thermal analysis, Brunauer-Emmett-Teller measurement, elemental analysis and X-ray photoelectron spectroscopy, respectively. Electrochemical properties have been studied by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements in 6 mol L{sup -1} potassium hydroxide. The activated carbon shows good capacitive behavior and the specific capacitance is up to 210 F g{sup -1}, which indicates that it may be a promising candidate for supercapacitors.

  11. Anionic sorbents for arsenic and technetium species.

    SciTech Connect

    Lucero, Daniel A.; Moore, Robert Charles; Bontchev, Ranko Panayotov; Hasan, Ahmed Ali Mohamed; Zhao, Hongting; Salas, Fred Manuel; Holt, Kathleen Caroline

    2003-09-01

    Two sorbents, zirconium coated zeolite and magnesium hydroxide, were tested for their effectiveness in removing arsenic from Albuquerque municipal water. Results for the zirconium coated zeolite indicate that phosphate present in the water interfered with the sorption of arsenic. Additionally, there was a large quantity of iron and copper present in the water, corrosion products from the piping system, which may have interfered with the uptake of arsenic by the sorbent. Magnesium hydroxide has also been proven to be a strong sorbent for arsenic as well as other metals. Carbonate, present in water, has been shown to interfere with the sorption of arsenic by reacting with the magnesium hydroxide to form magnesium carbonate. The reaction mechanism was investigated by FT-IR and shows that hydrogen bonding between an oxygen on the arsenic species and a hydrogen on the Mg(OH)2 is most likely the mechanism of sorption. This was also confirmed by RAMAN spectroscopy and XRD. Technetium exists in multiple oxidation states (IV and VII) and is easily oxidized from the relatively insoluble Tc(IV) form to the highly water soluble and mobile Tc(VII) form. The two oxidation states exhibit different sorption characteristics. Tc(VII) does not sorb to most materials whereas Tc(IV) will strongly sorb to many materials. Therefore, it was determined that it is necessary to first reduce the Tc (using SnCl2) before sorption to stabilize Tc in the environment. Additionally, the effect of carbonate and phosphate on the sorption of technetium by hydroxyapatite was studied and indicated that both have a significant effect on reducing Tc sorption.

  12. Sorbent-based sampling methods for volatile and semi-volatile organic compounds in air Part 1: Sorbent-based air monitoring options.

    PubMed

    Woolfenden, Elizabeth

    2010-04-16

    Sorbent tubes/traps are widely used in combination with gas chromatographic (GC) analytical methods to monitor the vapour-phase fraction of organic compounds in air. Target compounds range in volatility from acetylene and freons to phthalates and PCBs and include apolar, polar and reactive species. Airborne vapour concentrations will vary depending on the nature of the location, nearby pollution sources, weather conditions, etc. Levels can range from low percent concentrations in stack and vent emissions to low part per trillion (ppt) levels in ultra-clean outdoor locations. Hundreds, even thousands of different compounds may be present in any given atmosphere. GC is commonly used in combination with mass spectrometry (MS) detection especially for environmental monitoring or for screening uncharacterised workplace atmospheres. Given the complexity and variability of organic vapours in air, no one sampling approach suits every monitoring scenario. A variety of different sampling strategies and sorbent media have been developed to address specific applications. Key sorbent-based examples include: active (pumped) sampling onto tubes packed with one or more sorbents held at ambient temperature; diffusive (passive) sampling onto sorbent tubes/cartridges; on-line sampling of air/gas streams into cooled sorbent traps; and transfer of air samples from containers (canisters, Tedlar) bags, etc.) into cooled sorbent focusing traps. Whichever sampling approach is selected, subsequent analysis almost always involves either solvent extraction or thermal desorption (TD) prior to GC(/MS) analysis. The overall performance of the air monitoring method will depend heavily on appropriate selection of key sampling and analytical parameters. This comprehensive review of air monitoring using sorbent tubes/traps is divided into 2 parts. (1) Sorbent-based air sampling option. (2) Sorbent selection and other aspects of optimizing sorbent-based air monitoring methods. The paper presents

  13. Composite affinity sorbents and their cleaning in place.

    PubMed

    Girot, P; Moroux, Y; Duteil, X P; Nguyen, C; Boschetti, E

    1990-06-27

    Making large-scale affinity sorbents that are reusable under acceptable hygienic conditions implies specific treatments for cleaning in place with known aqueous solutions of chemical agents. However, common agents such as sodium hydroxide are frequently considered too drastic for the stability of macromolecular biologically active immobilized ligands. According to a large series of trials, it was found that only a mixture of sodium hydroxide and ethanol was actually effective in sterilizing a sorbent in a single step. When hydroxide or an ethanol-acetic acid mixture were used alone, they were not totally efficient in the inactivation of sporulated Bacillus subtilis. Conversely, they were efficient when used sequentially. All these solutions were able to remove pyrogens from chromatographic sorbents. As the sterilizing solutions contained a certain amount of ethanol, the most suitable chromatographic affinity sorbents had to be based on an incompressible matrix. When washing an affinity silica sorbent that had proteins as ligands with solutions such as sodium hydroxide, ethanol-acetic acid or ethanol-sodium hydroxide, it was found that certain sorbents were able to tolerate the treatments without a noticeable decrease in their biochemical activity.

  14. Engineered sorbent barriers for low-level waste disposal.

    SciTech Connect

    Freeman, H.D.; Mitchell, S.J.; Buelt, J.L.

    1986-12-01

    The Engineered Sorbent Barriers Program at Pacific Northwest Laboratory is investigating sorbent materials to prevent the migration of soluble radio nuclides from low-level waste sites. These materials would allow water to pass, preventing the bathtub effect at humid sites. Laboratory studies identifield promising sorbent materials for three key radionuclides: for cesium, greensand; for cobalt, activated charcoal; and for strontium, synthetic zeolite or clinoptilolite. Mixtures of these sorbent materials were tested in 0.6-m-diameter columns using radioactive leachates. To simulate expected worst-case conditions, the leachate solution contained the radionuclides, competing cations, and a chelating agent and was adjusted to a pH of 5. A sorbent barrier comprised of greensand (1 wt%), activated charcoal (6 wt%), synthetic zeolite (20 wt%), and local soil (73 wt%) achieved the decontamination factors necessary to meet the regulatory performance requirements established for this study. Sorbent barriers can be applied to shallow-land burial, as backfill around the waste or engineered structures, or as backup to other liner systems. 7 refs., 14 figs., 12 tabs.

  15. Activated carbon monoliths for methane storage

    NASA Astrophysics Data System (ADS)

    Chada, Nagaraju; Romanos, Jimmy; Hilton, Ramsey; Suppes, Galen; Burress, Jacob; Pfeifer, Peter

    2012-02-01

    The use of adsorbent storage media for natural gas (methane) vehicles allows for the use of non-cylindrical tanks due to the decreased pressure at which the natural gas is stored. The use of carbon powder as a storage material allows for a high mass of methane stored for mass of sample, but at the cost of the tank volume. Densified carbon monoliths, however, allow for the mass of methane for volume of tank to be optimized. In this work, different activated carbon monoliths have been produced using a polymeric binder, with various synthesis parameters. The methane storage was studied using a home-built, dosing-type instrument. A monolith with optimal parameters has been fabricated. The gravimetric excess adsorption for the optimized monolith was found to be 161 g methane for kg carbon.

  16. Solid-Sorbent Air Sampler

    NASA Technical Reports Server (NTRS)

    Galen, T. J.

    1986-01-01

    Portable unit takes eight 24-hour samples. Volatile organic compounds in air collected for analysis by portable, self-contained sampling apparatus. Sampled air drawn through sorbent material, commercial porous polymer of 2, 3-diphenyl-p-phenylene oxide. High-boiling-point organic compounds adsorbed onto polymer, while low-boiling-point organics pass through and returned to atmosphere. Sampler includes eight sample tubes filled with polymeric sorbent. Organic compounds in atmosphere absorbed when air pumped through sorbent. Designed for checking air in spacecraft, sampler adaptable to other applications as leak detection, gas-mixture analysis, and ambient-air monitoring.

  17. Novacon process: An alternative to limestone sorbents. Presentation to the Council of Industrial Boiler Owners, fluid bed XI. Held in Burke, Virginia, on November 14, 1995

    SciTech Connect

    Baer, S.H.; Luftglass, B.K.

    1995-12-31

    This paper presents the results of recent tests of a new type of sorbent useful for emissions control. The sorbent, referred to as thermally active marble (TAM), comprises a class of naturally-occurring metamorphic calcium carbonates. TAMs break down upon heating in combustors more evenly and with higher reactivity than limestone, resulting in better calcium utilization rates. Use of TAMS may also reduce NOx and CO emissions, excess air consumption and unburned carbon, and also improve combustion efficiency. In a full-scale (90 MW) demonstration comparing TAM to limestone, the Ca/S improved from 2.6 to 1.5 or better. Unburned carbon in fly ash decreased significantly and NOx levels were also reduced.

  18. Study of the adsorption of Cd and Zn onto an activated carbon: Influence of pH, cation concentration, and adsorbent concentration

    SciTech Connect

    Seco, A.; Marzal, P.; Gabaldon, C.; Ferrer, J.

    1999-06-01

    The single adsorption of Cd and Zn from aqueous solutions has been investigated on Scharlau Ca 346 granular activated carbon in a wide range of experimental conditions: pH, metal concentration, and carbon concentration. The results showed the efficiency of the activated carbon as sorbent for both metals. Metal removals increase on raising the pH and carbon concentration, and decrease on raising the initial metal concentration. The adsorption processes have been modeled using the surface complex formation (SCF) Triple Layer Model (TLM). The adsorbent TLM parameters were determined. Modeling has been performed assuming a single surface bidentate species or an overall surface species with fractional stoichiometry. The bidentate stoichiometry successfully predicted cadmium and zinc removals in all the experimental conditions. The Freundlich isotherm has been also checked.

  19. Process analysis of CO{sub 2} capture from flue gas using carbonation/calcination cycles

    SciTech Connect

    Li, Z.S.; Cai, N.S.; Croiset, E.

    2008-07-15

    Process analysis of CO{sub 2} capture from flue gas using Ca-based carbonation/calcination cycles is presented here. A carbonation/calcination system is composed essentially of two reactors (an absorber and a regenerator) with Ca-based sorbent circulating between the two reactors (assumed here as fluidized beds). CO{sub 2} is, therefore, transferred from the absorber to the regenerator. Because of the endothermicity of the calcination reaction, a certain amount of coal is burned with pure oxygen in the regenerator. Detailed mass balance, heat balance and cost of electricity and CO{sub 2} mitigation for the carbonation/calcination cycles with three Ca-based sorbents in dual fluidized beds were calculated and analyzed to study the effect of the Ca-based sorbent activity decay on CO{sub 2} capture from flue gas. The three sorbents considered were: limestone, dolomite and CaO/Ca{sub 12}Al{sub 14}O{sub 33} (75/25 wt %) sorbent. All results, including the amount of coal and oxygen required, are presented with respect to the difference in calcium oxide conversion between the absorber and the regenerator, which is an important design parameter. Finally, costs of electricity and CO{sub 2} mitigation costs using carbonation/calcination cycles for the three sorbents were estimated. The results indicate that the economics of the carbonation/calcination process compare favorably with competing technologies for capturing CO{sub 2}.

  20. Preparation of a new adsorbent from activated carbon and carbon nanofiber (AC/CNF) for manufacturing organic-vacbpour respirator cartridge

    PubMed Central

    2013-01-01

    In this study a composite of activated carbon and carbon nanofiber (AC/CNF) was prepared to improve the performance of activated carbon (AC) for adsorption of volatile organic compounds (VOCs) and its utilization for respirator cartridges. Activated carbon was impregnated with a nickel nitrate catalyst precursor and carbon nanofibers (CNF) were deposited directly on the AC surface using catalytic chemical vapor deposition. Deposited CNFs on catalyst particles in AC micropores, were activated by CO2 to recover the surface area and micropores. Surface and textural characterizations of the prepared composites were investigated using Brunauer, Emmett and Teller’s (BET) technique and electron microscopy respectively. Prepared composite adsorbent was tested for benzene, toluene and xylene (BTX) adsorption and then employed in an organic respirator cartridge in granular form. Adsorption studies were conducted by passing air samples through the adsorbents in a glass column at an adjustable flow rate. Finally, any adsorbed species not retained by the adsorbents in the column were trapped in a charcoal sorbent tube and analyzed by gas chromatography. CNFs with a very thin diameter of about 10-20 nm were formed uniformly on the AC/CNF. The breakthrough time for cartridges prepared with CO2 activated AC/CNF was 117 minutes which are significantly longer than for those cartridges prepared with walnut shell- based activated carbon with the same weight of adsorbents. This study showed that a granular form CO2 activated AC/CNF composite could be a very effective alternate adsorbent for respirator cartridges due to its larger adsorption capacities and lower weight. PMID:23369424

  1. The development of effective CaO-based CO2 sorbents via a sacrificial templating technique.

    PubMed

    Naeem, Muhammad Awais; Armutlulu, Andac; Broda, Marcin; Lebedev, Dmitry; Müller, Christoph R

    2016-10-20

    A carbon-based sacrificial templating approach was employed to realize single-pot synthesis of cyclically stable CaO-based CO2 sorbents. The sacrificial carbonaceous template was formed through resorcinol-formaldehyde polymerization reaction. The resultant sorbents following the thermal decomposition of the carbonaceous template featured an inverse opal-like macrostructure composed of a highly porous nanostructured backbone. In addition to pure CaO, sorbents supported with Al2O3, MgO, Y2O3, and ZrO2 were synthesized. SEM and XRD were utilized to characterize the morphology and the chemical composition of the synthetic CO2 sorbents, respectively. The cyclic CO2 uptake performance of the synthetic sorbents was assessed by TGA and compared to limestone. All of the synthetic sorbents exhibited an improved CO2 uptake performance when compared to limestone. The performance enhancement became more pronounced in the case of supported sorbents. The sorbent with the best CO2 uptake performance was supported by a mixture of Al2O3 and Y2O3, and exhibited a CO2 uptake of 0.61 g CO2/g CaO after 10 cycles of calcination and carbonation under practically relevant operating temperatures, which exceeded the CO2 uptake of limestone by more than 350%.

  2. Sulfidation of a Novel Iron Sorbent Supported on Lignite Chars during Hot Coal Gas Desulfurization

    NASA Astrophysics Data System (ADS)

    Yin, Fengkui; Yu, Jianglong; Gupta, Sushil; Wang, Shaoyan; Wang, Dongmei; Yang, Li; Tahmasebi, Arash

    The sulfidation behavior of novel iron oxide sorbents supported using activated-chars during desulfurization of hot coal gases has been studied. The sulfidation of the char-supported sorbents was investigated using a fixed-bed quartz reactor in the temperature range of 673K to 873K. The product gases were analyzed using a GC equipped with a TCD and a FPD detector. The sorbent samples before and after sulfidation were examined using SEM and XRD.

  3. Preparation of activated carbons with mesopores by use of organometallics

    SciTech Connect

    Yamada, Yoshio; Yoshizawa, Noriko; Furuta, Takeshi

    1996-12-31

    Activated carbons are commercially produced by steam or CO{sub 2} activation of coal, coconut shell and so on. In general the carbons obtained give pores with a broad range of distribution. The objective of this study was to prepare activated carbons from coal by use of various organometallic compounds. The carbons were evaluated for pore size by nitrogen adsorption experiments.

  4. Supercritical Carbon Dioxide Regeneration of Activated Carbon Loaded with Contaminants from Rocky Mountain Arsenal Well Water.

    DTIC Science & Technology

    1982-05-01

    15 111-7 GRANULAR ACTIVATED CARBON ADSORPTION ISOTHERMS THERMALLY REACTIVATED CARBON .............. 16 I IV-1 PROCESS FLOW DIAGRAM FOR... PROCESSING COST OF ACTIVATED CHARCOAL REGENERATION BY SUPERCRITICAL CARBON DIOXIDE PROCESS ........................... 25 l IV-4 SENSITIVITY OF GAC...regenerate adsorbents such as granular activated carbon loaded with a broad variety of organic adsorbates. This regeneration process uses a supercritical

  5. Making Activated Carbon for Storing Gas

    NASA Technical Reports Server (NTRS)

    Wojtowicz, Marek A.; Serio, Michael A.; Suuberg, Eric M.

    2005-01-01

    Solid disks of microporous activated carbon, produced by a method that enables optimization of pore structure, have been investigated as means of storing gas (especially hydrogen for use as a fuel) at relatively low pressure through adsorption on pore surfaces. For hydrogen and other gases of practical interest, a narrow distribution of pore sizes <2 nm is preferable. The present method is a variant of a previously patented method of cyclic chemisorption and desorption in which a piece of carbon is alternately (1) heated to the lower of two elevated temperatures in air or other oxidizing gas, causing the formation of stable carbon/oxygen surface complexes; then (2) heated to the higher of the two elevated temperatures in flowing helium or other inert gas, causing the desorption of the surface complexes in the form of carbon monoxide. In the present method, pore structure is optimized partly by heating to a temperature of 1,100 C during carbonization. Another aspect of the method exploits the finding that for each gas-storage pressure, gas-storage capacity can be maximized by burning off a specific proportion (typically between 10 and 20 weight percent) of the carbon during the cyclic chemisorption/desorption process.

  6. Sorption of priority pollutants to biochars and activated carbons for application to soil and sediment remediation

    NASA Astrophysics Data System (ADS)

    Beckingham, B.; Gomez-Eyles, J. L.; Kwon, S.; Riedel, G.; Gilmour, C.; Ghosh, U.

    2012-04-01

    The effectiveness of different biochars in comparison to 2 commercially available activated carbons (ACs) to sorb polychlorinated biphenyls (PCBs) and mercury (Hg) was assessed, with the aim of identifying promising materials for application to soil and sediment remediation and elucidating material properties that may enhance pollutant binding potential. Biochars studied were produced from pine dust, peanut hull, barley straw, and acai pit in addition to steam-activated biochars made from poultry litter (chicken and turkey). Aqueous concentrations of PCBs were measured using a polyoxymethylene passive sampling technique allowing a very low environmentally-relevant concentration range to be examined. Mercury pH-edge isotherms were conducted at relatively high concentrations in a wide pH range (pH 3-11). Sorption of Hg at low concentrations was also performed with ACs and two other biochars made from a marsh reed and a hard wood. Organic contaminant isotherms were analyzed by the Freundlich model, and Freundlich sorption coefficients (KFr) were normalized to a single concentration to allow comparison among materials (i.e. Kd). Values of Kd were related to the sorbent surface area, with sorption being greater for ACs than activated biochars, followed by unactivated biochars. ACs also had higher carbon content (80-90%) than biochars (22 - 77%). This sorption trend would thus be expected for adsorption of hydrophobic compounds to black carbon surfaces. In contrast, at high concentration all biochars removed more Hg from solution than ACs. Steam-activated poultry litter biochars showed the best performance, with consistent removal of >99.7% Hg over the entire pH range. The relatively high sulfur and phosphate content of these materials likely contribute to this enhanced Hg sorption. Also, owing to their lower pyrolysis temperatures relative to ACs, biochars are reported to have a greater surface group functionality which can enhance cation sorption. The importance of

  7. Adsorption of Hydantoins on Activated Carbon,

    DTIC Science & Technology

    1985-05-01

    performed for single solute, bisolute, and trisolute solutions as well as an undiluted coal gasification wastewater containing predominantly hydantoin...hydantoin, 5,5-dimethylhydantoin, and 5-ethyl-5-methylhydantoin. Absorption using activated carbon did not appear to be an effective treatment process for the removal of hydantoins from the coal gasification wastewater.

  8. ENGINEERING BULLETIN: GRANULAR ACTIVATED CARBON TREATMENT

    EPA Science Inventory

    Granular activated carbon (GAC) treatment is a physicochemical process that removes a wide variety of contaminants by adsorbing them from liquid and gas streams [1, p. 6-3]. This treatment is most commonly used to separate organic contaminants from water or air; however, it can b...

  9. USING POWDERED ACTIVATED CARBON: A CRITICAL REVIEW

    EPA Science Inventory

    Because the performance of powdered activated carbon (PAC) for uses other than taste and odor control is poorly documented, the purpose of this article is to critically review uses that have been reported (i.e., pesticides and herbicides, synthetic organic chemicals, and trihalom...

  10. MODELING MERCURY CONTROL WITH POWDERED ACTIVATED CARBON

    EPA Science Inventory

    The paper presents a mathematical model of total mercury removed from the flue gas at coal-fired plants equipped with powdered activated carbon (PAC) injection for Mercury control. The developed algorithms account for mercury removal by both existing equipment and an added PAC in...

  11. Development of Highly Durable and Reactive Regenerable Magnesium-Based Sorbents for CO2 Separation in Coal Gasification Process

    SciTech Connect

    Javad Abbasian; Armin Hassanzadeh Khayyat; Rachid B. Slimane

    2005-06-01

    The specific objective of this project was to develop physically durable and chemically regenerable MgO-based sorbents that can remove carbon dioxide from raw coal gas at operating condition prevailing in IGCC processes. A total of sixty two (62) different sorbents were prepared in this project. The sorbents were prepared either by various sol-gel techniques (22 formulations) or modification of dolomite (40 formulations). The sorbents were prepared in the form of pellets and in granular forms. The solgel based sorbents had very high physical strength, relatively high surface area, and very low average pore diameter. The magnesium content of the sorbents was estimated to be 4-6 % w/w. To improve the reactivity of the sorbents toward CO{sub 2}, The sorbents were impregnated with potassium salts. The potassium content of the sorbents was about 5%. The dolomite-based sorbents were prepared by calcination of dolomite at various temperature and calcination environment (CO{sub 2} partial pressure and moisture). Potassium carbonate was added to the half-calcined dolomite through wet impregnation method. The estimated potassium content of the impregnated sorbents was in the range of 1-6% w/w. In general, the modified dolomite sorbents have significantly higher magnesium content, larger pore diameter and lower surface area, resulting in significantly higher reactivity compared to the sol-gel sorbents. The reactivities of a number of sorbents toward CO{sub 2} were determined in a Thermogravimetric Analyzer (TGA) unit. The results indicated that at the low CO{sub 2} partial pressures (i.e., 1 atm), the reactivities of the sorbents toward CO{sub 2} are very low. At elevated pressures (i.e., CO{sub 2} partial pressure of 10 bar) the maximum conversion of MgO obtained with the sol-gel based sorbents was about 5%, which corresponds to a maximum CO{sub 2} absorption capacity of less than 1%. The overall capacity of modified dolomite sorbents were at least one order of magnitude

  12. Exploring molecular sieve capabilities of activated carbon fibers to reduce the impact of NOM preloading on trichloroethylene adsorption.

    PubMed

    Karanfil, Tanju; Dastgheib, Seyed A; Mauldin, Dina

    2006-02-15

    Adsorption of trichloroethylene (TCE) by two activated carbon fibers (ACFs) and two granular activated carbons (GACs) preloaded with hydrophobic and transphilic fractions of natural organic matter (NOM) was examined. ACF10, the most microporous activated carbon used in this study, had over 90% of its pore volume in pores smaller than 10 A. It also had the highest volume in pores 5-8 A, which is the optimum pore size region for TCE adsorption, among the four activated carbons. Adsorption of NOM fractions by ACF10 was, in general, negligible. Therefore, ACF10, functioning as a molecular sieve during preloading, exhibited the least NOM uptake for each fraction, and subsequently the highest TCE adsorption. The other three sorbents had wider pore size distributions, including high volumes in pores larger than 10 A, where NOM molecules can adsorb. As a result, they showed a higher degree of uptake for all NOM fractions, and subsequently lower adsorption capacities for TCE, as compared to ACF10. The results obtained in this study showed that understanding the interplay between the optimum pore size region for the adsorption of target synthetic organic contaminant (SOC) and the pore size region for the adsorption of NOM molecules is important for controlling NOM-SOC competitions. Experiments with different NOM fractions indicated that the degree of NOM loading is important in terms of preloading effects; however the waythatthe carbon pores are filled and loaded by different NOM fractions can be different and may create an additional negative impact on TCE adsorption.

  13. High capacity immobilized amine sorbents

    DOEpatents

    Gray, McMahan L.; Champagne, Kenneth J.; Soong, Yee; Filburn, Thomas

    2007-10-30

    A method is provided for making low-cost CO.sub.2 sorbents that can be used in large-scale gas-solid processes. The improved method entails treating an amine to increase the number of secondary amine groups and impregnating the amine in a porous solid support. The method increases the CO.sub.2 capture capacity and decreases the cost of utilizing an amine-enriched solid sorbent in CO.sub.2 capture systems.

  14. CFB sorbent selection enhances performance

    SciTech Connect

    Buecker, B.; Wofford, J.; DuBose, R.; Ray, D.

    1997-07-01

    The quality and particle size of the sorbent has a direct influence on the efficiency of sulfur dioxide (SO{sub 2}) removal in a circulating fluidized bed (CFB) boiler. This report outlines tests and subsequent operation of a CFB unit at the University of North Carolina at Chapel Hill Cogeneration Facility (UNC-CH) that proved how dramatically a change in sorbent can change the efficiency of performance.

  15. Supercapacitor Electrodes from Activated Carbon Monoliths and Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Dolah, B. N. M.; Othman, M. A. R.; Deraman, M.; Basri, N. H.; Farma, R.; Talib, I. A.; Ishak, M. M.

    2013-04-01

    Binderless monoliths of supercapacitor electrodes were prepared by the carbonization (N2) and activation (CO2) of green monoliths (GMs). GMs were made from mixtures of self-adhesive carbon grains (SACG) of fibers from oil palm empty fruit bunches and a combination of 5 & 6% KOH and 0, 5 & 6% carbon nanotubes (CNTs) by weight. The electrodes from GMs containing CNTs were found to have lower specific BET surface area (SBET). The electrochemical behavior of the supercapacitor fabricated using the prepared electrodes were investigated by electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD). In general an addition of CNTs into the GMs reduces the equivalent series resistance (ESR) value of the cells. A cell fabricated using electrodes from GM with 5% CNT and 5% KOH was found to have the largest reduction of ESR value than that from the others GMs containing CNT. The cell has steeper Warburg's slope than that from its respective non-CNT GM, which reflect the smaller resistance for electrolyte ions to move into pores of electrodes despite these electrodes having largest reduction in specific BET surface area. The cell also has the smallest reduction of specific capacitance (Csp) and maintains the specific power range despite a reduction in the specific energy range due to the CNT addition.

  16. Biochar from Coffee Residues: A New Promising Sorbent

    NASA Astrophysics Data System (ADS)

    Fotopoulou, Kalliopi; Karapanagioti, Hrissi; Manariotis, Ioannis

    2014-05-01

    Biochar is a carbon-rich material produced by heating biomass in an oxygen-limited environment. Biochar is mainly used as an additive to soils to sequester carbon and improve soil fertility as well as a sorbent for environmental remediation processes. Surface properties such as point of zero charge, surface area and pore volume, surface topography, surface functional groups and acid-base behavior are important factors, which affect sorption efficiency. Understanding the surface alteration of biochars increases our understanding of the pollutant-sorbent interaction. The objective of the present study was to characterize the surface properties of biochar produced, and to investigate the effect of thermal treatment conditions on key characteristics that affect sorptive properties. The espresso coffee residue was obtained after the coffee was brewed through espresso machines in coffee shops. The coffee residue was dried and kept in an oven at 50oC until its pyrolysis at 850oC. Pyrolysis with different coffee mass and containers were tested in order to find optimum biochar characteristics. Detailed characterization techniques were carried out to determine the properties of the produced biochar. The surface area, the pore volume, and the average pore size of the biochars were determined using gas (N2) adsorption-desorption cycles using the Brunauer, Emmett, and Teller (BET) equation. Open surface area and micropore volume were determined using the t-plot method and the Harkins & Jura equation. Total organic carbon was also determined because it is an important factor that affects sorption. The results were compared with the corresponding properties of activated carbons. The biochar produced exhibited a wide range of surface area from 21 to 770 m2/g and open surface area from 21 to 65 m2/g. It is obvious that the surface area results from the formation of pores. Actually it was calculated that up to 90% of the porosity is due to the micropores. More specifically the

  17. Influence of temperature and regeneration cycles on Hg capture and efficiency by structured Au/C regenerable sorbents.

    PubMed

    Ballestero, D; Gómez-Giménez, C; García-Díez, E; Juan, R; Rubio, B; Izquierdo, M T

    2013-09-15

    The objective of this work is to evaluate a novel regenerable sorbent for mercury capture based on gold nanoparticles supported on a honeycomb structured carbon monolith. A new methodology for gold nanoparticles deposition onto carbon monolith support has been developed to obtain an Au sorbent based on the direct reduction of a gold salt onto the carbon material. For comparison purposes, colloidal gold method was also used to obtain Au/C sorbents. Both types of sorbents were characterized by different techniques in order to obtain the bulk gold content, the particle size distribution and the chemical states of gold after deposition. The mercury capture capacity and mercury capture efficiency of sorbents were tested in a bench scale facility at different experimental conditions. The regenerability of the sorbents was tested along several cycles of Hg capture-regeneration. High retention efficiencies are found for both types of sorbents comparing their gold content. Moreover, the high retention efficiency is maintained along several cycles of Hg capture-regeneration. The study of the fresh sorbent, the sorbent after Hg exposition and after regeneration by XPS and XRD gives insight to explain those results.

  18. An Ultrahigh Pore Volume Drives Up the Amine Stability and Cyclic CO2 Capacity of a Solid-Amine@Carbon Sorbent.

    PubMed

    Gadipelli, Srinivas; Patel, Hasmukh A; Guo, Zhengxiao

    2015-09-02

    Carbon monoliths of ultrahigh pore volume (5.35 cm(3) g(-1) ) and high surface area (2700 m(2) g(-1) ) accommodate a record high level of amine(tetraethylenepentamine), up to 5 g g(-1) within its hierarchically networked micro-/mesopores over a wide range. Thus, this solid-amine@carbon shows exceptional CO2 sorption and stable cyclic capacities at simulated flue-gas conditions.

  19. Adsorption/oxidation of hydrogen sulfide on nitrogen-containing activated carbons

    SciTech Connect

    Adib, F.; Bagreev, A.; Bandosz, T.J.

    2000-02-22

    Wood-based activated carbon was modified by impregnation with urea and heat treatment at 450 and 950 C. The chemical and physical properties of materials were determined using acid/base titration, FTIR, thermal analysis, IGC, and sorption of nitrogen. The surface features were compared to those of a commercial urea-modified carbon. Then, the H{sub 2}S breakthrough capacity tests were carried out, and the sorption capacity was evaluated. The results showed that urea-modified sorbents have a capacity similar to that of the received material; however, the conversion of hydrogen sulfide to a water-soluble species is significantly higher. It happens due to a high dispersion of basic nitrogen compounds in the small pores of carbons, where oxidation of hydrogen sulfide ions to sulfur radicals followed by the creation of sulfur oxides and sulfuric acid occurs. It is proposed that the process proceeds gradually, from small pores to larger, and that the degree of microporosity is an important factor.

  20. Cooperative redox activation for carbon dioxide conversion

    NASA Astrophysics Data System (ADS)

    Lian, Zhong; Nielsen, Dennis U.; Lindhardt, Anders T.; Daasbjerg, Kim; Skrydstrup, Troels

    2016-12-01

    A longstanding challenge in production chemistry is the development of catalytic methods for the transformation of carbon dioxide into useful chemicals. Silane and borane promoted reductions can be fined-tuned to provide a number of C1-building blocks under mild conditions, but these approaches are limited because of the production of stoichiometric waste compounds. Here we report on the conversion of CO2 with diaryldisilanes, which through cooperative redox activation generate carbon monoxide and a diaryldisiloxane that actively participate in a palladium-catalysed carbonylative Hiyama-Denmark coupling for the synthesis of an array of pharmaceutically relevant diarylketones. Thus the disilane reagent not only serves as the oxygen abstracting agent from CO2, but the silicon-containing `waste', produced through oxygen insertion into the Si-Si bond, participates as a reagent for the transmetalation step in the carbonylative coupling. Hence this concept of cooperative redox activation opens up for new avenues in the conversion of CO2.

  1. The biomass derived activated carbon for supercapacitor

    NASA Astrophysics Data System (ADS)

    Senthilkumar, S. T.; Selvan, R. Kalai; Melo, J. S.

    2013-06-01

    In this work, the activated carbon was prepared from biowaste of Eichhornia crassipes by chemical activation method using KOH as the activating agent at various carbonization temperatures (600 °C, 700 °C and 800 °C). The disordered nature, morphology and surface functional groups of ACs were examined by XRD, SEM and FT-IR. The electrochemical properties of AC electrodes were studied in 1M H2SO4 in the potential range of -0.2 to 0.8 V using cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques in a three electrode system. Subsequently, the fabricated supercapacitor using AC electrode delivered the higher specific capacitance and energy density of 509 F/g at current density of 1 mA/cm2 and 17 Wh/kg at power density of 0.416 W/g.

  2. Field Testing of Activated Carbon Injection Options for Mercury Control at TXU's Big Brown Station

    SciTech Connect

    John Pavlish; Jeffrey Thompson; Christopher Martin; Mark Musich; Lucinda Hamre

    2009-01-07

    The primary objective of the project was to evaluate the long-term feasibility of using activated carbon injection (ACI) options to effectively reduce mercury emissions from Texas electric generation plants in which a blend of lignite and subbituminous coal is fired. Field testing of ACI options was performed on one-quarter of Unit 2 at TXU's Big Brown Steam Electric Station. Unit 2 has a design output of 600 MW and burns a blend of 70% Texas Gulf Coast lignite and 30% subbituminous Powder River Basin coal. Big Brown employs a COHPAC configuration, i.e., high air-to-cloth baghouses following cold-side electrostatic precipitators (ESPs), for particulate control. When sorbent injection is added between the ESP and the baghouse, the combined technology is referred to as TOXECON{trademark} and is patented by the Electric Power Research Institute in the United States. Key benefits of the TOXECON configuration include better mass transfer characteristics of a fabric filter compared to an ESP for mercury capture and contamination of only a small percentage of the fly ash with AC. The field testing consisted of a baseline sampling period, a parametric screening of three sorbent injection options, and a month long test with a single mercury control technology. During the baseline sampling, native mercury removal was observed to be less than 10%. Parametric testing was conducted for three sorbent injection options: injection of standard AC alone; injection of an EERC sorbent enhancement additive, SEA4, with ACI; and injection of an EERC enhanced AC. Injection rates were determined for all of the options to achieve the minimum target of 55% mercury removal as well as for higher removals approaching 90%. Some of the higher injection rates were not sustainable because of increased differential pressure across the test baghouse module. After completion of the parametric testing, a month long test was conducted using the enhanced AC at a nominal rate of 1.5 lb/Macf. During the

  3. Nanostructured Metal Oxide Sorbents for the Collection and Recovery of Uranium from Seawater

    SciTech Connect

    Chouyyok, Wilaiwan; Warner, Cynthia L.; Mackie, Katherine E.; Warner, Marvin G.; Gill, Gary A.; Addleman, Raymond S.

    2016-02-07

    The ability to collect uranium from seawater offers the potential for a long-term green fuel supply for nuclear energy. However, extraction of uranium, and other trace minerals, is challenging due to the high ionic strength and low mineral concentrations in seawater. Herein we evaluate the use of nanostructured metal oxide sorbents for the collection and recovery of uranium from seawater. Chemical affinity, chemical adsorption capacity and kinetics of preferred sorbent materials were evaluated. High surface area manganese and iron oxide nanomaterials showed excellent performance for uranium collection from seawater. Inexpensive nontoxic carbonate solutions were demonstrated to be an effective and environmental benign method of stripping the uranium from the metal oxide sorbents. Various formats for the utilization of the nanostructured metals oxide sorbent materials are discussed including traditional and nontraditional methods such as magnetic separation. Keywords: Uranium, nano, manganese, iron, sorbent, seawater, magnetic, separations, nuclear energy

  4. Modeling of heavy metals removal from aqueous solution using activated carbon produced from cotton stalk.

    PubMed

    El Zayat, Mohamed; Smith, Edward

    2013-01-01

    Activated carbon produced from cotton stalks was examined for the removal of heavy metal contaminants. Adsorption studies in completely mixed batch reactors were used to generate equilibrium pH adsorption edges. Continuous flow experiments using the activated carbon in fixed beds were conducted to determine heavy metal breakthrough versus bed volumes treated. At given pH value in the range 5-7, the adsorption capacity was similar for copper and lead and clearly greater than for cadmium. A surface titration experiment indicated negative surface charge of the activated carbon at pH > 6, meaning that electrostatic attraction of the divalent heavy metals can occur below the pH required for precipitation. Substantive metal removal below the pH of zero charge might be due to surface complexation. Accordingly, a surface complexation model approach that utilizes an electrostatic term in the double-layer description was used to estimate equilibrium constants for the protolysis interactions of the activated carbon surface as well as equilibria between background ions used to establish ionic strength and the sorbent surface. Pb(II) adsorption edges were best modeled using inner-layer surface complexation of Pb(2+), while Cd(II) and Cu(II) data were best fit by outer-layer complexes with Me(2+). The full set of equilibrium constants were used as input in a dual-rate dynamic model to simulate the breakthrough curves of the target metals (Pb, Cu and Cd) from fixed bed experiments and to estimate external (or film) diffusion and internal (surface) diffusion coefficients.

  5. Carbon nanomaterials: Biologically active fullerene derivatives.

    PubMed

    Bogdanović, Gordana; Djordjević, Aleksandar

    2016-01-01

    Since their discovery, fullerenes, carbon nanotubes, and graphene attract significant attention of researches in various scientific fields including biomedicine. Nano-scale size and a possibility for diverse surface modifications allow carbon nanoallotropes to become an indispensable nanostructured material in nanotechnologies, including nanomedicine. Manipulation of surface chemistry has created diverse populations of water-soluble derivatives of fullerenes, which exhibit different behaviors. Both non-derivatized and derivatized fullerenes show various biological activities. Cellular processes that underline their toxicity are oxidative, genotoxic, and cytotoxic responses.The antioxidant/cytoprotective properties of fullerenes and derivatives have been considered in the prevention of organ oxidative damage and treatment. The same unique physiochemical properties of nanomaterials may also be associated with potential health hazards. Non-biodegradability and toxicity of carbon nanoparticles still remain a great concern in the area of biomedical application. In this review, we report on basic physical and chemical properties of carbon nano-clusters--fullerenes, nanotubes, and grapheme--their specificities, activities, and potential application in biological systems. Special emphasis is given to our most important results obtained in vitro and in vivo using polyhydroxylated fullerene derivative C₆₀(OH)₂₄.

  6. The NOVACON{trademark} process: A new class of sorbent technology

    SciTech Connect

    Baer, S.H.; Luftglass, B.K.

    1997-12-31

    This paper discusses a newly-introduced class of sorbent useful for reducing sulfur dioxide (SO{sub 2}) emissions in circulating fluidized bed (CFB) boilers. The sorbent, called thermally active marble (TAM), comprises a class of naturally recrystallized, metamorphic calcium carbonate (CaCO{sub 3}) products which range in purities from at least 54--98% CaCO{sub 3} and have thus far been found in numerous locations. Because of their physical properties, TAMs break down upon heating more evenly and with higher reactivities than limestone, resulting in better calcium utilization rates. Calcium/sulfur ratios and tonnage feed rates have improved by up to 40% in commercial demonstrations compared with conventional limestones. The introduction of TAMs also causes significant changes in the combustion environment, which has been shown to lead to a reduction in nitrogen oxides (NO{sub x}) and carbon monoxide (CO), as well as better carbon burnout in fly ash and bed ash. The results of tests of TAMs in pilot scale and commercial scale CFB boilers are described. Findings from testing in other boiler applications, including a pulverized coal boiler simulator, are also briefly presented.

  7. Enhanced capacitive properties of commercial activated carbon by re-activation in molten carbonates

    NASA Astrophysics Data System (ADS)

    Lu, Beihu; Xiao, Zuoan; Zhu, Hua; Xiao, Wei; Wu, Wenlong; Wang, Dihua

    2015-12-01

    Simple, affordable and green methods to improve capacitive properties of commercial activated carbon (AC) are intriguing since ACs possess a predominant role in the commercial supercapacitor market. Herein, we report a green reactivation of commercial ACs by soaking ACs in molten Na2CO3-K2CO3 (equal in mass ratios) at 850 °C combining the merits of both physical and chemical activation strategies. The mechanism of molten carbonate treatment and structure-capacitive activity correlations of the ACs are rationalized. Characterizations show that the molten carbonate treatment increases the electrical conductivity of AC without compromising its porosity and wettability of electrolytes. Electrochemical tests show the treated AC exhibited higher specific capacitance, enhanced high-rate capability and excellent cycle performance, promising its practical application in supercapacitors. The present study confirms that the molten carbonate reactivation is a green and effective method to enhance capacitive properties of ACs.

  8. Kinetics of adsorption with granular, powdered, and fibrous activated carbon

    SciTech Connect

    Shmidt, J.L.; Pimenov, A.V.; Lieberman, A.I.; Cheh, H.Y.

    1997-08-01

    The properties of three different types of activated carbon, fibrous, powdered, and granular, were investigated theoretically and experimentally. The adsorption rate of the activated carbon fiber was found to be two orders of magnitude higher than that of the granular activated carbon, and one order of magnitude higher than that of the powdered activated carbon. Diffusion coefficients of methylene blue in the fibrous, powdered, and granular activated carbons were determined experimentally. A new method for estimating the meso- and macropore surface areas in these carbons was proposed.

  9. Activation Effect of Fullerene C60 on the Carbon Dioxide Absorption Performance of Amine-Rich Polypropylenimine Dendrimers.

    PubMed

    Andreoli, Enrico; Barron, Andrew R

    2015-08-24

    Converting amine-rich compounds into highly effective carbon dioxide (CO2 ) sorbents requires a better understanding and control of their properties. The reaction of fullerene C60 with polyethyleneimine converts the polymer into a high-performance CO2 sorbent. In this study, experimental evidence is reported for the activation effect of C60 on the amine moieties of the polymer. To do so, polypropylenimine (PPI) dendrimers that allowed for a systematic comparison of molecular composition and CO2 absorption were used. The addition of C60 to PPI to form PPI-C60 results in a reduction of the energy barrier of CO2 absorption, but also in a parallel decrease in the frequency of successful collisions between CO2 and PPI-C60 due to a possible disruption of the hydrogen-bonding network of amino groups and bound water in PPI. This finding supports the existence of a non-affinity "repulsive" effect between hydrophobic C60 and hydrophilic amines that forces them to be actively exposed to CO2.

  10. Hydroxyapatite-based sorbents: elaboration, characterization and application for the removal of catechol from the aqueous phase.

    PubMed

    Sebei, Haroun; Minh, Doan Pham; Lyczko, Nathalie; Sharrock, Patrick; Nzihou, Ange

    2016-12-26

    Hydroxyapatite (HAP) is highly considered as good sorbent for the removal of metals from the aqueous phase. However, soluble metals co-exist with organic pollutants in wastewaters. But little work has been devoted to investigate the reactivity of HAP for the removal of organic compounds. The main objective of this work is to study the reactivity of HAP-based sorbents for the removal of catechol as a model organic pollutant from an aqueous solution. Thus, HAP sorbents were firstly synthesized using calcium carbonate and potassium dihydrogen phosphate under moderate conditions (25-80°C, atmospheric pressure). A zinc-doped HAP was also used as sorbent, which was obtained from the contact of HAP with an aqueous solution of zinc nitrate. All the sorbents were characterized by different standard physico-chemical techniques. The sorption of catechol was carried out in a batch reactor under stirring at room temperature and pressure. Zinc-doped HAP sorbent was found to be more reactive than non-doped HAP sorbents for the fixation of catechol. The highest sorption capacity was of 15 mg of C per gram of zinc-doped HAP sorbent. The results obtained suggest the reaction scheme of HAP sorbents with metals and organic pollutants when HAP sorbents were used for the treatment of complex wastewaters.

  11. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Quarterly technical progress report No. 1, October--December 1986

    SciTech Connect

    Jha, M.C.; Baltich, L.K.

    1987-02-23

    AMAX Research & Development Center (AMAX R&D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  12. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 1, Bench-scale testing and analysis

    SciTech Connect

    Jha, M.C.; Berggren, M.H.

    1989-05-02

    AMAX Research & Development Center (AMAX R&D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  13. Adsorption of low concentration phosphine in yellow phosphorus off-gas by impregnated activated carbon.

    PubMed

    Wang, Xueqian; Ning, Ping; Shi, Yan; Jiang, Ming

    2009-11-15

    In order to utilize high concentration CO comprehensively, impregnated activated carbon sorbent and the catalytic oxidation reaction for PH(3) were investigated in this study. Carbon was impregnated with HCl, KNO(3), or hexanediol. The activated carbon modified by 7% (mass fraction) HCl could enhance the adsorption purification ability significantly. Raising the reaction temperature or increasing the oxygen content of the gas can improve the purification efficiency. The structure of the materials after modification was determined using nitrogen adsorption. The modification decreased the volume of pores smaller than 2 nm in diameter with the most noticeable change occurring in the micropores ranging from 0.3 nm to 1.5 nm in diameter. Decreases in micropore volume accounted for 87% of the total pore volume change. After the adsorption, the surface areas decreased 28%, 29% of which was due to decreased micropore surface. HCl significantly increased the performance of carbon as a PH(3) adsorbent when HCl impregnation was applied whereas the effects of other materials used in this study were much less pronounced. HCl present in the small pores probably acted as a catalyst for oxygen activation that caused PH(3) oxidation. As a result of this process, H(3)PO(4) and P(4)O(10) were formed, strongly adsorbed, and present in the small pores ranging from 0.3 nm to 1.5 nm. In conclusion, this study provides evidence that CO from industrial off-gas can be purified and used as the raw material for a broader range of products.

  14. High temperature removal of hydrogen sulfide using an N-150 sorbent.

    PubMed

    Ko, T H; Chu, H; Chaung, L K; Tseng, T K

    2004-10-18

    In this study, an N-150 sorbent was used as a high temperature desulfurization sorbent for the removal of hydrogen sulfide from coal gas in a fixed bed reactor. The results indicate that the N-150 sorbent could be used for H(2)S removal in the tested temperature ranges. Regeneration test also reveals that utilization of the N-150 sorbent maintains up to 85% compared to the fresh sorbent. No significant degeneration occurs on the N-150 sorbent. In addition, various concentrations of H(2)S, H(2) and CO were also considered in the performance test of the N-150 sorbent. Except for H(2)S, H(2) and CO act the important roles in the high temperature desulfurization. By increasing the H(2) concentration, the sulfur capacity of the sorbent decreases and an adverse result is observed in the case of increasing CO concentration. This can be explained via water-shift reaction. On the basis of the instrument analysis, X-ray powder diffraction determination and SEM images with EDS spectrum characterization, residual sulfur is found in the regenerated N-150 sorbent and this sulfur species is sulfate which resulted by incomplete regeneration. The sulfate formation and sintering effect are major reasons to cause activity loss in the sulfidation/regeneration cycles.

  15. Trace elements removal from water using modified activated carbon.

    PubMed

    Campos, V; Buchler, P M

    2008-02-01

    This paper present the possible alternative options for the remove of trace elements from drinking water supplies in the trace. Arsenic and chromium are two of the most toxic pollutants, introduced into natural waters from a variety of sources and causing various adverse effects on living bodies. The performance of three filter bed methods was evaluated in the laboratory. Experiments were conducted to investigate the sorption of arsenic and chromium on carbon steel and removal of trace elements from drinking water with a household filtration process. The affinity of the arsenic and chromium species for Fe/Fe3C (iron/iron carbide) sites is the key factor controlling the removal of the elements. The method is based on the use of powdered block carbon, powder carbon steel and ceramic spheres in the ion-sorption columns as a cleaning process. The modified powdered block carbon is a satisfactory and economical sorbent for trace elements (arsenite and chromate) dissolved in water due to its low unit cost of about $23 and compatibility with the traditional household filtration system.

  16. Evaluation of a new carbon/zirconia-based sorbent for cleanup of food extracts in multiclass analysis of pesticides and environmental contaminants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel carbon/zirconia based material, SupelTM QuE Verde (Verde), was evaluated in a filter-vial dispersive solid phase extraction (d-SPE) cleanup of QuEChERS extracts of pork, salmon, kale, and avocado for residual analysis of pesticides and environmental contaminants. Low pressure (LP) GC-MS/MS w...

  17. Aqueous mercury adsorption by activated carbons.

    PubMed

    Hadi, Pejman; To, Ming-Ho; Hui, Chi-Wai; Lin, Carol Sze Ki; McKay, Gordon

    2015-04-15

    Due to serious public health threats resulting from mercury pollution and its rapid distribution in our food chain through the contamination of water bodies, stringent regulations have been enacted on mercury-laden wastewater discharge. Activated carbons have been widely used in the removal of mercuric ions from aqueous effluents. The surface and textural characteristics of activated carbons are the two decisive factors in their efficiency in mercury removal from wastewater. Herein, the structural properties and binding affinity of mercuric ions from effluents have been presented. Also, specific attention has been directed to the effect of sulfur-containing functional moieties on enhancing the mercury adsorption. It has been demonstrated that surface area, pore size, pore size distribution and surface functional groups should collectively be taken into consideration in designing the optimal mercury removal process. Moreover, the mercury adsorption mechanism has been addressed using equilibrium adsorption isotherm, thermodynamic and kinetic studies. Further recommendations have been proposed with the aim of increasing the mercury removal efficiency using carbon activation processes with lower energy input, while achieving similar or even higher efficiencies.

  18. A sensitive microextraction by packed sorbent-based methodology combined with ultra-high pressure liquid chromatography as a powerful technique for analysis of biologically active flavonols in wines.

    PubMed

    Silva, Catarina L; Gonçalves, João L; Câmara, José S

    2012-08-20

    A new approach based on microextraction by packed sorbent (MEPS) and reversed-phase high-throughput ultra high pressure liquid chromatography (UHPLC) method that uses a gradient elution and diode array detection to quantitate three biologically active flavonols in wines, myricetin, quercetin, and kaempferol, is described. In addition to performing routine experiments to establish the validity of the assay to internationally accepted criteria (selectivity, linearity, sensitivity, precision, accuracy), experiments are included to assess the effect of the important experimental parameters such as the type of sorbent material (C2, C8, C18, SIL, and C8/SCX), number of extraction cycles (extract-discard), elution volume, sample volume, and ethanol content, on the MEPS performance. The optimal conditions of MEPS extraction were obtained using C8 sorbent and small sample volumes (250μL) in five extraction cycle and in a short time period (about 5min for the entire sample preparation step). Under optimized conditions, excellent linearity (R(values)(2)>0.9963), limits of detection of 0.006μgmL(-1) (quercetin) to 0.013μgmL(-1) (myricetin) and precision within 0.5-3.1% were observed for the target flavonols. The average recoveries of myricetin, quercetin and kaempferol for real samples were 83.0-97.7% with relative standard deviation (RSD, %) lower than 1.6%. The results obtained showed that the most abundant flavonol in the analyzed samples was myricetin (5.8±3.7μgmL(-1)). Quercetin (0.97±0.41μgmL(-1)) and kaempferol (0.66±0.24μgmL(-1)) were found in a lower concentration. The optimized MEPS(C8) method was compared with a reverse-phase solid-phase extraction (SPE) procedure using as sorbent a macroporous copolymer made from a balanced ratio of two monomers, the lipophilic divinylbenzene and the hydrophilic N-vinylpyrrolidone (Oasis HLB) were used as reference. MEPS(C8) approach offers an attractive alternative for analysis of flavonols in wines, providing a number of

  19. ROLE OF POROSITY LOSS IN LIMITING SO2 CAPTURE BY CALCIUM BASED SORBENTS

    EPA Science Inventory

    The extent of high temperature (900-1,300°C), short time (<1 s) SO2 capture was found to be limited by temperature-dependent losses in the porosity of calcium based sorbents. At 970°C these porosity losses were caused by CO2-activated sintering. Sulfation of the sorbents either p...

  20. PREPARATION AND EVALUATION OF MODIFIED LIME AND SILICA-LIME SORBENTS FOR MERCURY VAPOR EMISSIONS CONTROL

    EPA Science Inventory

    The paper discusses current efforts to improve the uptake of mercury species by increasing active sites and adding oxidative species to the sorbent. (NOTE: Previous work showed that mercury chloride vapor is readily absorbed by calcium-based sorbents as an acid gas in environmen...

  1. Less-costly activated carbon for sewage treatment

    NASA Technical Reports Server (NTRS)

    Ingham, J. D.; Kalvinskas, J. J.; Mueller, W. A.

    1977-01-01

    Lignite-aided sewage treatment is based on absorption of dissolved pollutants by activated carbon. Settling sludge is removed and dried into cakes that are pyrolyzed with lignites to yield activated carbon. Lignite is less expensive than activated carbon previously used to supplement pyrolysis yield.

  2. 78 FR 13894 - Certain Activated Carbon From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-01

    ... COMMISSION Certain Activated Carbon From China Determination On the basis of the record \\1\\ developed in the... antidumping duty order on certain activated carbon from China would be likely to lead to continuation or... USITC Publication 4381 (February 2013), entitled Certain Activated Carbon from China: Investigation...

  3. Solid-phase extraction-capillary electrophoresis-mass spectrometry for the determination of tetracyclines residues in surface water by using carbon nanotubes as sorbent material.

    PubMed

    Suárez, B; Santos, B; Simonet, B M; Cárdenas, S; Valcárcel, M

    2007-12-14

    Last years chemical properties of carbon nanotubes (CNTs) have attracted high interest. One of the most important issues is the capability of CNTs to adsorb analytes on its surface. In this work, such property has been used to preconcentrate trace tetracyclines from environmental water samples at the trace level. Multi-walled carbon nanotubes (MWNTs) have showed higher capacity than other two single-walled carbon nanotubes (SWNTs). Preconcentration of the samples was performed in a flow system at-line coupled to the CE-MS equipment. The preconcentration of tetracyclines on MWNTs followed by capillary electrophoresis-mass spectrometry allows the detection of 0.30-0.69 microg/L of tetracyclines for the analysis of 10 mL of samples. Recoveries for the analysis of spiked samples ranged from 98.6 to 103.2% and the precision from 5.4 to 8.2%. Separation of tetracylines in the electrophoretic system was achieved using 50 mM formic acid at pH 2.0 as a background electrolyte. Atmospheric pressure electrospray ionization mass spectrometry detection was accomplished using 50:50 (v/v) methanol/water containing 0.5% (v/v) formic acid as a sheath liquid.

  4. Batch and dynamic sorption of Ni(II) ions by activated carbon based on a native lignocellulosic precursor.

    PubMed

    Nabarlatz, Debora; de Celis, Jorge; Bonelli, Pablo; Cukierman, Ana Lea

    2012-04-30

    Vinal-derived Activated Carbon (VAC) developed by phosphoric acid activation of sawdust from Prosopis ruscifolia native wood was tested for the adsorption of Ni(II) ions from dilute solutions in both batch and dynamic modes, comparing it with a Commercial Activated Carbon (CAC). Batch experiments were performed to determine adsorption kinetics and equilibrium isotherms for both carbons. It was possible to remove near 6.55 mg Ni g(-1) VAC and 7.65 mg Ni g(-1) CAC after 5 h and 10 h contact time, respectively. A pseudo second order equation fitted well with the kinetics of the process, and Langmuir adsorption model was used to adjust the experimental results concerning the adsorption isotherm. The parameters obtained indicate a stronger interaction between sorbent and sorbate for VAC (K = 26.56 L mmol(-1)) than for CAC (K = 19.54 L mmol(-1)). Continuous experiments were performed in a fixed-bed column packed with the investigated carbons, evaluating the influence of operational parameters such as flow rate, bed height and feed concentration on the breakthrough curves obtained. The breakthrough occurred more slowly for low concentrations of the metal ion in the feed, low flow rates and high bed height. The breakthrough curves were properly represented by Hall's model for both carbon types. Regeneration of the vinal activated carbon in column was tested, obtaining the same breakthrough curve in a new cycle of use. Finally, vinal-derived activated carbon can effectively be used to treat wastewater having until 30 ppm Ni(II).

  5. Carbon Monoxide Dehydrogenase Activity in Bradyrhizobium japonicum

    PubMed Central

    Lorite, María J.; Tachil, Jörg; Sanjuán, Juán; Meyer, Ortwin; Bedmar, Eulogio J.

    2000-01-01

    Bradyrhizobium japonicum strain 110spc4 was capable of chemolithoautotrophic growth with carbon monoxide (CO) as a sole energy and carbon source under aerobic conditions. The enzyme carbon monoxide dehydrogenase (CODH; EC 1.2.99.2) has been purified 21-fold, with a yield of 16% and a specific activity of 58 nmol of CO oxidized/min/mg of protein, by a procedure that involved differential ultracentrifugation, anion-exchange chromatography, hydrophobic interaction chromatography, and gel filtration. The purified enzyme gave a single protein and activity band on nondenaturing polyacrylamide gel electrophoresis and had a molecular mass of 230,000 Da. The 230-kDa enzyme was composed of large (L; 75-kDa), medium (M; 28.4-kDa), and small (S; 17.2-kDa) subunits occurring in heterohexameric (LMS)2 subunit composition. The 75-kDa polypeptide exhibited immunological cross-reactivity with the large subunit of the CODH of Oligotropha carboxidovorans. The B. japonicum enzyme contained, per mole, 2.29 atoms of Mo, 7.96 atoms of Fe, 7.60 atoms of labile S, and 1.99 mol of flavin. Treatment of the enzyme with iodoacetamide yielded di(carboxamidomethyl)molybdopterin cytosine dinucleotide, identifying molybdopterin cytosine dinucleotide as the organic portion of the B. japonicum CODH molybdenum cofactor. The absorption spectrum of the purified enzyme was characteristic of a molybdenum-containing iron-sulfur flavoprotein. PMID:10788353

  6. Carbon monoxide dehydrogenase activity in Bradyrhizobium japonicum.

    PubMed

    Lorite, M J; Tachil, J; Sanjuán, J; Meyer, O; Bedmar, E J

    2000-05-01

    Bradyrhizobium japonicum strain 110spc4 was capable of chemolithoautotrophic growth with carbon monoxide (CO) as a sole energy and carbon source under aerobic conditions. The enzyme carbon monoxide dehydrogenase (CODH; EC 1.2.99.2) has been purified 21-fold, with a yield of 16% and a specific activity of 58 nmol of CO oxidized/min/mg of protein, by a procedure that involved differential ultracentrifugation, anion-exchange chromatography, hydrophobic interaction chromatography, and gel filtration. The purified enzyme gave a single protein and activity band on nondenaturing polyacrylamide gel electrophoresis and had a molecular mass of 230,000 Da. The 230-kDa enzyme was composed of large (L; 75-kDa), medium (M; 28.4-kDa), and small (S; 17.2-kDa) subunits occurring in heterohexameric (LMS)(2) subunit composition. The 75-kDa polypeptide exhibited immunological cross-reactivity with the large subunit of the CODH of Oligotropha carboxidovorans. The B. japonicum enzyme contained, per mole, 2.29 atoms of Mo, 7.96 atoms of Fe, 7.60 atoms of labile S, and 1.99 mol of flavin. Treatment of the enzyme with iodoacetamide yielded di(carboxamidomethyl)molybdopterin cytosine dinucleotide, identifying molybdopterin cytosine dinucleotide as the organic portion of the B. japonicum CODH molybdenum cofactor. The absorption spectrum of the purified enzyme was characteristic of a molybdenum-containing iron-sulfur flavoprotein.

  7. Hierarchically structured activated carbon for ultracapacitors

    PubMed Central

    Kim, Mok-Hwa; Kim, Kwang-Bum; Park, Sun-Min; Roh, Kwang Chul

    2016-01-01

    To resolve the pore-associated bottleneck problem observed in the electrode materials used for ultracapacitors, which inhibits the transport of the electrolyte ions, we designed hierarchically structured activated carbon (HAC) by synthesizing a mesoporous silica template/carbon composite and chemically activating it to simultaneously remove the silica template and increase the pore volume. The resulting HAC had a well-designed, unique porous structure, which allowed for large interfaces for efficient electric double-layer formation. Given the unique characteristics of the HAC, we believe that the developed synthesis strategy provides important insights into the design and fabrication of hierarchical carbon nanostructures. The HAC, which had a specific surface area of 1,957 m2 g−1, exhibited an extremely high specific capacitance of 157 F g−1 (95 F cc−1), as well as a high rate capability. This indicated that it had superior energy storage capability and was thus suitable for use in advanced ultracapacitors. PMID:26878820

  8. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL

    SciTech Connect

    Gary M. Blythe

    2000-12-01

    A test program is being sponsored by the US Department of Energy (DOE), EPRI, FirstEnergy, and TVA to investigate furnace injection of alkaline sorbents as a means of reducing sulfuric acid concentrations in the flue gas from coal-fired boilers. This test program is being conducted at the FirstEnergy Bruce Mansfield Plant (BMP), although later testing will be conducted at a TVA plant. A sorbent injection test was conducted the week of April 18, 2000. The test was the first of several short-term (one- to two-week duration) tests to investigate the effectiveness of various alkaline sorbents for sulfuric acid control and the effects of these sorbents on boiler equipment performance. This first short-term test investigated the effect of injecting dry dolomite powder (CaCO{sub 3} {center_dot} MgCO{sub 3}), a mineral similar to limestone, into the furnace of Unit 2. During the test program, various analytical techniques were used to assess the effects of sorbent injection. These primarily included sampling with the controlled condensation system (CCS) for determining flue gas SO{sub 3} content and an acid dew-point (ADP) meter for determining the sulfuric acid dew point (and, indirectly, the concentration of sulfuric acid) of the flue gas. EPA Reference Method 26a was used for determining hydrochloric acid (HCl) and hydrofluoric acid (HF), as well and chlorine (Cl{sub 2}) and fluorine (F{sub 2}) concentrations in the flue gas. Fly ash resistivity was measured using a Southern Research Institute (SRI) point-to-plane resistivity probe, and unburned carbon in fly ash was determined by loss on ignition (LOI). Coal samples were also collected and analyzed for a variety of parameters. Finally, visual observations were made of boiler furnace and convective pass surfaces prior to and during sorbent injection.

  9. Photothermal desorption of single-walled carbon nanotubes and coconut shell-activated carbons using a continuous light source for application in air sampling.

    PubMed

    Floyd, Evan L; Sapag, Karim; Oh, Jonghwa; Lungu, Claudiu T

    2014-08-01

    Many techniques exist to measure airborne volatile organic compounds (VOCs), each with differing advantages; sorbent sampling is compact, versatile, has good sample stability, and is the preferred technique for collecting VOCs for hygienists. Development of a desorption technique that allows multiple analyses per sample (similar to chemical desorption) with enhanced sensitivity (similar to thermal desorption) would be helpful to field hygienists. In this study, activated carbon (AC) and single-walled carbon nanotubes (SWNT) were preloaded with toluene vapor and partially desorbed with light using a common 12-V DC, 50-W incandescent/halogen lamp. A series of experimental chamber configurations were explored starting with a 500-ml chamber under static conditions, then with low ventilation and high ventilation, finally a 75-ml high ventilation chamber was evaluated. When preloaded with toluene and irradiated at the highest lamp setting for 4min, AC desorbed 13.9, 18.5, 23.8, and 45.9% of the loaded VOC mass, in each chamber configuration, respectively; SWNT desorbed 25.2, 24.3, 37.4, and 70.5% of the loaded VOC mass, respectively. SWNT desorption was significantly greater than AC in all test conditions (P = 0.02-<0.0001) demonstrating a substantial difference in sorbent performance. When loaded with 0.435mg toluene and desorbed at the highest lamp setting for 4min in the final chamber design, the mean desorption for AC was 45.8% (39.7, 52.0) and SWNT was 72.6% (68.8, 76.4) (mean represented in terms of 95% confidence interval). All desorption measurements were obtained using a field grade photoionization detector; this demonstrates the potential of using this technique to perform infield prescreening of VOC samples for immediate exposure feedback and in the analytical lab to introduce sample to a gas chromatograph for detailed analysis of the sample.

  10. Photothermal Desorption of Single-Walled Carbon Nanotubes and Coconut Shell-Activated Carbons Using a Continuous Light Source for Application in Air Sampling

    PubMed Central

    Floyd, Evan L.; Sapag, Karim; Oh, Jonghwa; Lungu, Claudiu T.

    2014-01-01

    Many techniques exist to measure airborne volatile organic compounds (VOCs), each with differing advantages; sorbent sampling is compact, versatile, has good sample stability, and is the preferred technique for collecting VOCs for hygienists. Development of a desorption technique that allows multiple analyses per sample (similar to chemical desorption) with enhanced sensitivity (similar to thermal desorption) would be helpful to field hygienists. In this study, activated carbon (AC) and single-walled carbon nanotubes (SWNT) were preloaded with toluene vapor and partially desorbed with light using a common 12-V DC, 50-W incandescent/halogen lamp. A series of experimental chamber configurations were explored starting with a 500-ml chamber under static conditions, then with low ventilation and high ventilation, finally a 75-ml high ventilation chamber was evaluated. When preloaded with toluene and irradiated at the highest lamp setting for 4min, AC desorbed 13.9, 18.5, 23.8, and 45.9% of the loaded VOC mass, in each chamber configuration, respectively; SWNT desorbed 25.2, 24.3, 37.4, and 70.5% of the loaded VOC mass, respectively. SWNT desorption was significantly greater than AC in all test conditions (P = 0.02–<0.0001) demonstrating a substantial difference in sorbent performance. When loaded with 0.435mg toluene and desorbed at the highest lamp setting for 4min in the final chamber design, the mean desorption for AC was 45.8% (39.7, 52.0) and SWNT was 72.6% (68.8, 76.4) (mean represented in terms of 95% confidence interval). All desorption measurements were obtained using a field grade photoionization detector; this demonstrates the potential of using this technique to perform infield prescreening of VOC samples for immediate exposure feedback and in the analytical lab to introduce sample to a gas chromatograph for detailed analysis of the sample. PMID:25016598

  11. Sorbent characterization for FBC application

    SciTech Connect

    Pisupati, S.V.; Scaroni, A.W.

    1994-12-31

    Fluidized-bed boilers operating at both atmospheric and elevated pressures have received considerable attention from utilities and independent power producers because of their ability to remove SO{sub 2} from the flue gas during combustion and to minimize NO{sub x} production. The technology has advanced rapidly in the 1980s because of its adaptability to a range of fuel types, boiler capacities, and operating conditions without seriously compromising efficiency or performance. A sorbent, typically limestone or dolostone, is used in the fluidized-bed boiler to capture the combustion-generated SO{sub 2}. Many CFBC boiler operators are now realizing that optimizing sorbent usage is important for economical and environmentally acceptable operation of their plants. It is reported (mostly based on studies using a few sorbents) that particle size, porosity and pore size distribution, extent of sulfation, combustor temperature, pressure and CaCO{sub 3} content affect extent of sulfation.

  12. Laboratory scale studies of Pd/{gamma}-Al{sub 2}O{sub 3} sorbents for the removal of trace contaminants from coal-derived fuel gas at elevated temperatures

    SciTech Connect

    Rupp, Erik C.; Granite, Evan J.; Stanko, Dennis C.

    2013-01-01

    The Integrated Gasification Combined Cycle (IGCC) is a promising technology for the use of coal in a clean and efficient manner. In order to maintain the overall efficiency of the IGCC process, it is necessary to clean the fuel gas of contaminants (sulfur, trace compounds) at warm (150–540 °C) to hot (>540 °C) temperatures. Current technologies for trace contaminant (such as mercury) removal, primarily activated carbon based sorbents, begin to lose effectiveness above 100 °C, creating the need to develop sorbents effective at elevated temperatures. As trace elements are of particular environmental concern, previous work by this group has focused on the development of a Pd/γ-Al{sub 2}O{sub 3} sorbent for Hg removal. This paper extends the research to Se (as hydrogen selenide, H{sub 2}Se), As (as arsine, AsH{sub 3}), and P (as phosphine, PH{sub 3}) which thermodynamic studies indicate are present as gaseous species under gasification conditions. Experiments performed under ambient conditions in He on 20 wt.% Pd/γ-Al{sub 2}O{sub 3} indicate the sorbent can remove the target contaminants. Further work is performed using a 5 wt.% Pd/γ-Al{sub 2}O{sub 3} sorbent in a simulated fuel gas (H{sub 2}, CO, CO{sub 2}, N{sub 2} and H{sub 2}S) in both single and multiple contaminant atmospheres to gauge sorbent performance characteristics. The impact of H{sub 2}O, Hg and temperature on sorbent performance is explored.

  13. Activated carbons and low cost adsorbents for remediation of tri- and hexavalent chromium from water.

    PubMed

    Mohan, Dinesh; Pittman, Charles U

    2006-09-21

    Hexavalent chromium is a well-known highly toxic metal, considered a priority pollutant. Industrial sources of Cr(VI) include leather tanning, cooling tower blowdown, plating, electroplating, anodizing baths, rinse waters, etc. The most common method applied for chromate control is reduction of Cr(VI) to its trivalent form in acid (pH approximately 2.0) and subsequent hydroxide precipitation of Cr(III) by increasing the pH to approximately 9.0-10.0 using lime. Existing overviews of chromium removal only cover selected technologies that have traditionally been used in chromium removal. Far less attention has been paid to adsorption. Herein, we provide the first review article that provides readers an overview of the sorption capacities of commercial developed carbons and other low cost sorbents for chromium remediation. After an overview of chromium contamination is provided, more than 300 papers on chromium remediation using adsorption are discussed to provide recent information about the most widely used adsorbents applied for chromium remediation. Efforts to establish the adsorption mechanisms of Cr(III) and Cr(VI) on various adsorbents are reviewed. Chromium's impact environmental quality, sources of chromium pollution and toxicological/health effects is also briefly introduced. Interpretations of the surface interactions are offered. Particular attention is paid to comparing the sorption efficiency and capacities of commercially available activated carbons to other low cost alternatives, including an extensive table.

  14. Water Utility Lime Sludge Reuse – An Environmental Sorbent ...

    EPA Pesticide Factsheets

    Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up included a simulated flue gas preparation unit, a lab-scale wet scrubber, and a mercury analyzer system. The influent mercury concentration was based on a range from 22 surveyed power plants. The reactivity of the lime sludge sample for acid neutralization was determined using a method similar to method ASTM C1318-95. Similar experiments were conducted using reagent calcium carbonate and calcium sulfate to obtain baseline data for comparing with the lime sludge test results. The project also evaluated the techno-economic feasibility and sustainable benefits of reusing lime softening sludge. If implemented on a large scale, this transformative approach for recycling waste materials from water treatment utilities at power generation utilities for environmental cleanup can save both water and power utilities millions of dollars. Huge amounts of lime sludge waste, generated from hundreds of water treatment utilities across the U.S., is currently disposed in landfills. This project evaluated a sustainable and economically-attractive approach to the use of lime sludge waste as a valuable resource for power generation utilities.

  15. Performance of a novel synthetic Ca-based solid sorbent suitable for desulfurizing flue gases in a fluidized bed

    SciTech Connect

    Pacciani, R.; Muller, C.R.; Davidson, J.F.; Dennis, J.S.; Hayhurst, A.N.

    2009-08-05

    The extent and mechanism of sulfation and carbonation of limestone, dolomite, and chalk, were compared with a novel, synthetic sorbent (85 wt % CaO and 15 wt % Ca{sub 12}A{sub l14}O{sub 33}), by means of experiments undertaken in a small, electrically heated fluidized bed. The sorbent particles were used either (I) untreated, sieved to two particle sizes and reacted with two different concentrations of SO{sub 2}, or (ii) after being cycled 20 times between carbonation, in 15 vol % CO{sub 2} in N2, and calcination, in pure N2, at 750 degrees C. The uptake of untreated limestone and dolomite was generally low (<0.2 g(SO{sub 2})/g(sorbent)), confirming previous results, However, the untreated chalk and the synthetic sorbent were found to be substantially more reactive with SO{sub 2}, and their final uptake was significantly higher (>0.5 g(SO{sub 2})/g(sorbent)) and essentially independent of the particle size. Here, comparisons are made on the basis of the sorbents in the calcined state. The capacities for the uptake of SO{sub 2}, on a basis of unit mass of calcined sorbent, were comparable for the chalk and the synthetic sorbent. However, previous work has demonstrated the ability of the synthetic sorbent to retain its capacity for CO{sub 2} over many cycles of carbonation and calcination: much more so than natural sorbents such as chalk and limestone. Accordingly, the advantage of the synthetic sorbent is that it could be used to remove CO{sub 2} from flue gases and, at the end of its life, to remove SO{sub 2} on a once-through basis.

  16. Impact of oxy-fuel combustion gases on mercury retention in activated carbons from a macroalgae waste: effect of water.

    PubMed

    Lopez-Anton, M A; Ferrera-Lorenzo, N; Fuente, E; Díaz-Somoano, M; Suarez-Ruíz, I; Martínez-Tarazona, M R; Ruiz, B

    2015-04-01

    The aim of this study is to understand the different sorption behaviors of mercury species on activated carbons in the oxy-fuel combustion of coal and the effect of high quantities of water vapor on the retention process. The work evaluates the interactions between the mercury species and a series of activated carbons prepared from a macroalgae waste (algae meal) from the agar-agar industry in oxy-combustion atmospheres, focussing on the role that the high concentration of water in the flue gases plays in mercury retention. Two novel aspects are considered in this work (i) the impact of oxy-combustion gases on the retention of mercury by activated carbons and (ii) the performance of activated carbons prepared from biomass algae wastes for this application. The results obtained at laboratory scale indicate that the effect of the chemical and textural characteristics of the activated carbons on mercury capture is not as important as that of reactive gases, such as the SOx and water vapor present in the flue gas. Mercury retention was found to be much lower in the oxy-combustion atmosphere than in the O2+N2 (12.6% O2) atmosphere. However, the oxidation of elemental mercury (Hg0) to form oxidized mercury (Hg2+) amounted to 60%, resulting in an enhancement of mercury retention in the flue gas desulfurization units and a reduction in the amalgamation of Hg0 in the CO2 compression unit. This result is of considerable importance for the development of technologies based on activated carbon sorbents for mercury control in oxy-combustion processes.

  17. Improved Regenerative Sorbent-Compressor Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1992-01-01

    Conceptual regenerative sorbent-compressor refrigerator attains regeneration efficiency and, therefore, overall power efficiency and performance greater than conventional refrigerators. Includes two fluid loops. In one, CH2FCF3 (R134a) ciculates by physical adsorption and desorption in four activated-charcoal sorption compressors. In other, liquid or gas coolant circulated by pump. Wave of regenerative heating and cooling propagates cyclically like peristatic wave among sorption compressors and associated heat exchangers. Powered by electricity, oil, gas, solar heat, or waste heat. Used as air conditioners, refrigerators, and heat pumps in industrial, home, and automotive applications.

  18. Activated carbon briquettes from biomass materials.

    PubMed

    Amaya, Alejandro; Medero, Natalia; Tancredi, Néstor; Silva, Hugo; Deiana, Cristina

    2007-05-01

    Disposal of biomass wastes, produced in different agricultural activities, is frequently an environmental problem. A solution for such situation is the recycling of these residues for the production of activated carbon, an adsorbent which has several applications, for instance in the elimination of contaminants. For some uses, high mechanical strength and good adsorption characteristics are required. To achieve this, carbonaceous materials are conformed as pellets or briquettes, in a process that involves mixing and pressing of char with adhesive materials prior to activation. In this work, the influence of the operation conditions on the mechanical and surface properties of briquettes was studied. Eucalyptus wood and rice husk from Uruguay were used as lignocellulosic raw materials, and concentrated grape must from Cuyo Region-Argentina, as a binder. Different wood:rice and solid:binder ratios were used to prepare briquettes in order to study their influence on mechanical and surface properties of the final products.

  19. Cooperative redox activation for carbon dioxide conversion

    PubMed Central

    Lian, Zhong; Nielsen, Dennis U.; Lindhardt, Anders T.; Daasbjerg, Kim; Skrydstrup, Troels

    2016-01-01

    A longstanding challenge in production chemistry is the development of catalytic methods for the transformation of carbon dioxide into useful chemicals. Silane and borane promoted reductions can be fined-tuned to provide a number of C1-building blocks under mild conditions, but these approaches are limited because of the production of stoichiometric waste compounds. Here we report on the conversion of CO2 with diaryldisilanes, which through cooperative redox activation generate carbon monoxide and a diaryldisiloxane that actively participate in a palladium-catalysed carbonylative Hiyama-Denmark coupling for the synthesis of an array of pharmaceutically relevant diarylketones. Thus the disilane reagent not only serves as the oxygen abstracting agent from CO2, but the silicon-containing ‘waste', produced through oxygen insertion into the Si–Si bond, participates as a reagent for the transmetalation step in the carbonylative coupling. Hence this concept of cooperative redox activation opens up for new avenues in the conversion of CO2. PMID:27981967

  20. Adsorbed natural gas storage with activated carbon

    SciTech Connect

    Sun, Jian; Brady, T.A.; Rood, M.J.

    1996-12-31

    Despite technical advances to reduce air pollution emissions, motor vehicles still account for 30 to 70% emissions of all urban air pollutants. The Clean Air Act Amendments of 1990 require 100 cities in the United States to reduce the amount of their smog within 5 to 15 years. Hence, auto emissions, the major cause of smog, must be reduced 30 to 60% by 1998. Natural gas con be combusted with less pollutant emissions. Adsorbed natural gas (ANG) uses adsorbents and operates with a low storage pressure which results in lower capital costs and maintenance. This paper describes the production of an activated carbon adsorbent produced from an Illinois coal for ANG.

  1. Charcoal and activated carbon at elevated pressure

    SciTech Connect

    Antal, M.J. Jr.; Dai, Xiangfeng; Norberg, N.

    1995-12-01

    High quality charcoal has been produced with very high yields of 50% to 60% from macadamia nut and kukui nut shells and of 44% to 47% from Eucalyptus and Leucaena wood in a bench scale unit at elevated pressure on a 2 to 3 hour cycle, compared to commercial practice of 25% to 30% yield on a 7 to 12 day operating cycle. Neither air pollution nor tar is produced by the process. The effects of feedstock pretreatments with metal additives on charcoal yield are evaluated in this paper. Also, the influences of steam and air partial pressure and total pressure on yields of activated carbon from high yield charcoal are presented.

  2. Characteristics and reactivity of rapidly hydrated sorbent for semidry flue gas desulfurization

    SciTech Connect

    Jie Zhang; Changfu You; Suwei Zhao; Changhe Chen; Haiying Qi

    2008-03-01

    The semidry flue gas desulfurization (FGD) process has many advantages over the wet FGD process for moving sulfur dioxide emissions from pulverized coal-fired power plants. Semidry FGD with a rapidly hydrated sorbent was studied in a pilot-scale circulating fluidized bed (CFB) experimental facility. The sorbent was made from lumps of lime and coal fly ash. The desulfurization efficiency was measured for various operating parameters, including the sorbent recirculation rate and the water spray method. The experimental results show that the desulfurization efficiencies of the rapidly hydrated sorbent were 1.5-3.0 times higher than a commonly used industrial sorbent for calcium to sulfur molar ratios from 1.2 to 3.0, mainly due to the higher specific surface area and pore volume. The Ca(OH){sub 2} content in the cyclone separator ash was about 2.9% for the rapidly hydrated sorbent and was about 0.1% for the commonly used industrial sorbent, due to the different adhesion between the fine Ca(OH){sub 2} particles and the fly ash particles, and the low cyclone separation efficiency for the fine Ca(OH){sub 2} particles that fell off the sorbent particles. Therefore the actual recirculation rates of the active sorbent with Ca(OH){sub 2} particles were higher for the rapidly hydrated sorbent, which also contributed to the higher desulfurization efficiency. The high fly ash content in the rapidly hydrated sorbent resulted in good operating stability. The desulfurization efficiency with upstream water spray was 10-15% higher than that with downstream water spray. 20 refs., 7 figs., 1 tab.

  3. Production of activated carbon from TCR char

    NASA Astrophysics Data System (ADS)

    Stenzel, Fabian; Heberlein, Markus; Klinner, Tobias; Hornung, Andreas

    2016-04-01

    The utilization of char for adsorptive purposes is known since the 18th century. At that time the char was made of wood or bones and used for decoloration of fluids. In the 20th century the production of activated carbon in an industrial scale was started. The today's raw materials for activated carbon production are hard coal, peat, wood or coconut shells. All these materials entail costs especially the latter. Thus, the utilization of carbon rich residues (biomass) is an interesting economic opportunity because it is available for no costs or even can create income. The char is produced by thermo-catalytic reforming (TCR®). This process is a combination of an intermediate pyrolysis and subsequently a reforming step. During the pyrolysis step the material is decomposed in a vapor and a solid carbon enriched phase. In the second step the vapor and the solid phase get in an intensive contact and the quality of both materials is improved via the reforming process. Subsequently, the condensables are precipitated from the vapor phase and a permanent gas as well as oil is obtained. Both are suitable for heat and power production which is a clear advantage of the TCR® process. The obtained biochar from the TCR® process has special properties. This material has a very low hydrogen and oxygen content. Its stability is comparable to hard coal or anthracite. Therefore it consists almost only of carbon and ash. The latter depends from input material. Furthermore the surface structure and area can be influenced during the reforming step. Depending from temperature and residence time the number of micro pores and the surface area can be increased. Preliminary investigations with methylene blue solution have shown that a TCR® char made of digestate from anaerobic digestion has adsorptive properties. The decoloration of the solution was achieved. A further influencing factor of the adsorption performance is the particle size. Based on the results of the preliminary tests a

  4. A solid-phase microextraction fiber with carbon nanoparticles as sorbent material prepared by a simple flame-based preparation process.

    PubMed

    Sun, Min; Feng, Juanjuan; Qiu, Huamin; Fan, Lulu; Li, Leilei; Luo, Chuannan

    2013-07-26

    A novel carbon nanoparticles-coated solid-phase microextraction (SPME) fiber was prepared via a simple and low-cost flame-based preparation process, with stainless steel wire as support. Surface characteristic of the fiber was studied with scanning electron microscope. A nano-scaled brushy structure was observed. Coupled to gas chromatography (GC), the fiber was used to extract phthalate esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. Analytical performances of the proposed method were investigated under the optimum extraction conditions (extraction temperature, 40°C; content of KCl, 30% (w/v); extraction time, 50min for PAEs and 40min for PAHs) and compared with other reports for the same analytes. Calibration ranges were 0.06-500μgL(-1) for di-n-butyl phthalate (DBP), and 0.1-300μgL(-1) for di-cyclohexyl phthalate (DCHP) and di-(2-ethyl-hexyl) phthalate (DEHP). For the eight PAHs, good linearity was obtained ranging from 0.01 to 150μgL(-1). Limits of detection were 0.005μgL(-1) for three PAEs and 0.001-0.003μgL(-1) for eight PAHs. The fiber exhibited excellent stability. It can be used for 100 times with RSDs of extraction efficiency less than 22.4%. The as-established SPME-GC method was applied to determine PAEs in food-wrap and PAHs in cigarette ash and snow water, and satisfactory results were obtained. The carbon nanoparticles-coated SPME fiber was efficient for sampling of organic compounds from aqueous samples.

  5. Adsorption study of an organo-arsenical with chitosan-based sorbents.

    PubMed

    Poon, Louis; Younus, Shaguftah; Wilson, Lee D

    2014-04-15

    In this study, chitosan-based copolymers were prepared at various weight ratios of chitosan (C) to glutaraldehyde (G): 1:1 (CG11), 2:1 (CG21), and 3:1 (CG31). The sorption properties of these copolymers were investigated with roxarsone in simulated aquatic conditions at pH 7 in phosphate buffer, similar to that found in poultry litter leachate. The relative sorption capacity (Q(m); mmol/g) of the sorbents are listed in parentheses in descending order: CG11 (1.80)>CG31 (0.945)>CG21 (0.802)>chitosan (0.416). The sorptive properties of the copolymers are comparable to granular activated carbon (GAC), a standard carbonaceous sorbent material, where Q(m)=2.36 mmol/g. The adsorption properties of phenolic adsorbates such as o-nitrophenol, p-nitrophenol, and roxarsone with the CG copolymers and GAC were investigated at various pH and compared with phosphate and carbonate buffer systems.

  6. ENTRAINED-FLOW ADSORPTION OF MERCURY USING ACTIVATED CARBON

    EPA Science Inventory

    Bench-scale experiments were conducted in a flow reactor to simulate entrained-flow capture of elemental mercury (Hg) by activated carbon. Adsorption of Hg by several commercial activated carbons was examined at different carbon-to-mercury (C:Hg) ratios (by weight) (600:1 - 29000...

  7. Preparation of binderless activated carbon monolith from pre-carbonization rubber wood sawdust by controlling of carbonization and activation condition

    NASA Astrophysics Data System (ADS)

    Taer, E.; Deraman, M.; Taslim, R.; Iwantono

    2013-09-01

    Binderless activated carbon monolith (ACM) was prepared from pre-carbonized rubber wood sawdust (RWSD). The effect of the carbonization temperature (400, 500, 600, 700, 800 dan 900 °C) on porosity characteristic of the ACM have been studied. The optimum carbonization temperature for obtaining ACM with high surface area of 600 °C with CO2 activation at 800 °C for one hour. At this condition, the surface area as high as 733 m2 g-1 could be successfully obtained. By improved the activation temperature at 900 °C for 2.5 h, it was found that the surface area of 860 m2 g-1. For this condition, the ACM exhibit the specific capacitance of 90 F g-1. In addition the termogravimertic (TG)-differential termografimertic (DTG) and field emission scanning electron microscope (FESEM) measurement were also performed on the ACMs and the result has been studied. Finally, it was conclude that the high surface area of ACM from RWSD could be produced by proper selections of carbonization and activation condition.

  8. Plant diversity increases soil microbial activity and soil carbon storage.

    PubMed

    Lange, Markus; Eisenhauer, Nico; Sierra, Carlos A; Bessler, Holger; Engels, Christoph; Griffiths, Robert I; Mellado-Vázquez, Perla G; Malik, Ashish A; Roy, Jacques; Scheu, Stefan; Steinbeiss, Sibylle; Thomson, Bruce C; Trumbore, Susan E; Gleixner, Gerd

    2015-04-07

    Plant diversity strongly influences ecosystem functions and services, such as soil carbon storage. However, the mechanisms underlying the positive plant diversity effects on soil carbon storage are poorly understood. We explored this relationship using long-term data from a grassland biodiversity experiment (The Jena Experiment) and radiocarbon ((14)C) modelling. Here we show that higher plant diversity increases rhizosphere carbon inputs into the microbial community resulting in both increased microbial activity and carbon storage. Increases in soil carbon were related to the enhanced accumulation of recently fixed carbon in high-diversity plots, while plant diversity had less pronounced effects on the decomposition rate of existing carbon. The present study shows that elevated carbon storage at high plant diversity is a direct function of the soil microbial community, indicating that the increase in carbon storage is mainly limited by the integration of new carbon into soil and less by the decomposition of existing soil carbon.

  9. Regenerative Cu/La zeolite supported desulfurizing sorbents

    NASA Technical Reports Server (NTRS)

    Voecks, Gerald E. (Inventor); Sharma, Pramod K. (Inventor)

    1991-01-01

    Efficient, regenerable sorbents for removal of H2S from fluid hydrocarbons such as diesel fuel at moderate condition comprise a porous, high surface area aluminosilicate support, suitably a synthetic zeolite, and most preferably a zeolite having a free lattice opening of at least 6 Angstroms containing from 0.1 to 0.5 moles of copper ions, lanthanum ions or their mixtures. The sorbent removes sulfur from the hydrocarbon fuel in high efficiency and can be repetitively regenerated without loss of activity.

  10. PROCEEDINGS: MULTIPOLLUTANT SORBENT REACTIVITY WORKSHOP

    EPA Science Inventory

    The report is a compilation of technical papers and visual aids presented by representatives of industry, academia, and government agencies at a workshop on multipollutant sorbent reactivity that was held at EPA's Environmental Research Center in Research Triangle Park, NC, on Ju...

  11. Preparation of activated carbons from bituminous coal pitches

    NASA Astrophysics Data System (ADS)

    Gañan, J.; González-García, C. M.; González, J. F.; Sabio, E.; Macías-García, A.; Díaz-Díez, M. A.

    2004-11-01

    High-porosity carbons were prepared from bituminous coal pitches by combining chemical and physical activation. The chemical activation process consisted of potassium hydroxide impregnation followed by carbonization in nitrogen atmosphere. The effect of the KOH impregnation ratio on the surface area and pore volumes evolution of the carbons derived from mesophase pitch was studied. The optimum KOH:pitch ratio was fixed to realize a physical activation process in order to increase the textural parameters of the KOH-activated carbons. Physical activation was performed by carbonizing the KOH-activated carbons followed by gasifying with air. The influence of the carbonization temperature and the residence time of the gasification with air were explored to optimize those preparation parameters.

  12. Separating DDTs in edible animal fats using matrix solid-phase dispersion extraction with activated carbon filter, Toyobo-KF.

    PubMed

    Furusawa, Naoto

    2006-09-01

    A technique is presented for the economical, routine, and quantitative analysis of contamination by dichloro-diphenyl-trichloroethanes (DDTs) [pp'-DDT, pp'-dichlorodiphenyl dichloroethylene, and pp'-dichlorodiphenyl dichloreothane in beef tallow and chicken fat samples, based on their separation using matrix solid-phase dispersion (MSPD) extraction with Toyobo-KF, an activated carbon fiber. Toyobo-KF is a newly applied MSPD sorbent, and it is followed by reversed-phase high-performance liquid chromatography (HPLC) with a photodiode array detector. The resulting analytical performance parameters [recoveries of spiked DDTs (0.1, 0.2, and 0.4 microg/g) > or = 81%, with relative standard deviations of < or = 8% (n = 5), and quantitation limits < or = 0.03 microg/g], with minimal handling and cost-efficiency, indicate that the present MSPD-HPLC method may be a useful tool for routine monitoring of DDT contamination in meat.

  13. Impacts of Activated Carbon Amendment on Hg Methylation, Demethylation and Microbial Activity in Marsh Soils

    NASA Astrophysics Data System (ADS)

    Gilmour, C. C.; Ghosh, U.; Santillan, E. F. U.; Soren, A.; Bell, J. T.; Butera, D.; McBurney, A. W.; Brown, S.; Henry, E.; Vlassopoulos, D.

    2015-12-01

    In-situ sorbent amendments are a low-impact approach for remediation of contaminants in sediments, particular in habitats like wetlands that provide important ecosystem services. Laboratory microcosm trials (Gilmour et al. 2013) and early field trials show that activated carbon (AC) can effectively increase partitioning of both inorganic Hg and methylmercury to the solid phase. Sediment-water partitioning can serve as a proxy for Hg and MeHg bioavailability in soils. One consideration in using AC in remediation is its potential impact on organisms. For mercury, a critical consideration is the potential impact on net MeHg accumulation and bioavailability. In this study, we specifically evaluated the impact of AC on rates of methylmercury production and degradation, and on overall microbial activity, in 4 different Hg-contaminated salt marsh soils. The study was done over 28 days in anaerobic, sulfate-reducing slurries. A double label of enriched mercury isotopes (Me199Hg and inorganic 201Hg) was used to separately follow de novo Me201Hg production and Me199Hg degradation. AC amendments decreased both methylation and demethylation rate constants relative to un-amended controls, but the impact on demethylation was stronger. The addition of 5% (dry weight) regenerated AC to soil slurries drove demethylation rate constants to nearly zero; i.e. MeHg sorption to AC almost totally blocked its degradation. The net impact was increased solid phase MeHg concentrations in some of the soil slurries with the highest methylation rate constants. However, the net impact of AC amendments was to increase MeHg (and inorganic Hg) partitioning to the soil phase and decrease concentrations in the aqueous phase. AC significantly decreased aqueous phase inorganic Hg and MeHg concentrations after 28 days. Overall, the efficacy of AC in reducing aqueous MeHg was highest in the soils with the highest MeHg concentrations. The AC addition did not significantly impact microbial activity, as

  14. REPEATED REDUCTIVE AND OXIDATIVE TREATMENTS ON GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    Fenton oxidation and Fenton oxidation preceded by reduction solutions were applied to granular activated carbon (GAC) to chemically regenerate the adsorbent. No adsorbate was present on the GAC so physicochemical effects from chemically aggressive regeneration of the carbon coul...

  15. Reduction of bromate by granular activated carbon

    SciTech Connect

    Kirisits, M.J.; Snoeyink, V.L.; Kruithof, J.C.

    1998-07-01

    Ozonation of waters containing bromide can lead to the formation of bromate, a probable human carcinogen. Since bromate will be regulated at 10 {micro}g/L by the Stage 1 Disinfectants/Disinfection By-Products Rule, there is considerable interest in finding a suitable method of bromate reduction. Granular activated carbon (GAC) can be used to chemically reduce bromate to bromide, but interference from organic matter and anions present in natural water render this process inefficient. In an effort to improve bromate reduction by GAC, several modifications were made to the GAC filtration process. The use of a biologically active carbon (BAC) filter ahead of a fresh GAC filter with and without preozonation, to remove the biodegradable organic matter, did not substantially improve the bromate removal of the GAC filter. The use of the BAC filter for biological bromate reduction proved to be the most encouraging experiment. By lowering the dissolved oxygen in the influent to the BAC from 8.0 mg/L to 2.0 mg/L, the percent bromate removal increased from 42% to 61%.

  16. Activated Carbon Fibers For Gas Storage

    SciTech Connect

    Burchell, Timothy D; Contescu, Cristian I; Gallego, Nidia C

    2017-01-01

    The advantages of Activated Carbon Fibers (ACF) over Granular Activated Carbon (GAC) are reviewed and their relationship to ACF structure and texture are discussed. These advantages make ACF very attractive for gas storage applications. Both adsorbed natural gas (ANG) and hydrogen gas adsorption performance are discussed. The predicted and actual structure and performance of lignin-derived ACF is reviewed. The manufacture and performance of ACF derived monolith for potential automotive natural gas (NG) storage applications is reported Future trends for ACF for gas storage are considered to be positive. The recent improvements in NG extraction coupled with the widespread availability of NG wells means a relatively inexpensive and abundant NG supply in the foreseeable future. This has rekindled interest in NG powered vehicles. The advantages and benefit of ANG compared to compressed NG offer the promise of accelerated use of ANG as a commuter vehicle fuel. It is to be hoped the current cost hurdle of ACF can be overcome opening ANG applications that take advantage of the favorable properties of ACF versus GAC. Lastly, suggestions are made regarding the direction of future work.

  17. Deep Bed Iodine Sorbent Testing FY 2011 Report

    SciTech Connect

    Nick Soelberg; Tony Watson

    2011-08-01

    Nuclear fission results in the production of fission products (FPs) and activation products that increasingly interfere with the fission process as their concentrations increase. Some of these fission and activation products tend to evolve in gaseous species during used nuclear fuel reprocessing. Analyses have shown that I129, due to its radioactivity, high potential mobility in the environment, and high longevity (half life of 15.7 million years), can require control efficiencies of up to 1,000x or higher to meet regulatory emission limits. Deep-bed iodine sorption testing has been done to evaluate the performance of solid sorbents for capturing iodine in off-gas streams from nuclear fuel reprocessing plants. The objectives of the FY 2011 deep bed iodine sorbent testing are: (1) Evaluate sorbents for iodine capture under various conditions of gas compositions and operating temperature (determine sorption efficiencies, capacities, and mass transfer zone depths); and (2) Generate data for dynamic iodine sorption modeling. Three tests performed this fiscal year on silver zeolite light phase (AgZ-LP) sorbent are reported here. Additional tests are still in progress and can be reported in a revision of this report or a future report. Testing was somewhat delayed and limited this year due to initial activities to address some questions of prior testing, and due to a period of maintenance for the on-line GC. Each test consisted of (a) flowing a synthetic blend of gases designed to be similar to an aqueous dissolver off-gas stream over the sorbent contained in three separate bed segments in series, (b) measuring each bed inlet and outlet gas concentrations of iodine and methyl iodide (the two surrogates of iodine gas species considered most representative of iodine species expected in dissolver off-gas), (c) operating for a long enough time to achieve breakthrough of the iodine species from at least one (preferably the first two) bed segments, and (d) post-test purging

  18. Electrochemical activation of carbon nanotube/polymer composites.

    PubMed

    Sánchez, Samuel; Fàbregas, Esteve; Pumera, Martin

    2009-01-07

    Electrochemical activation of carbon nanotube/polysulfone composite electrodes for enhanced heterogeneous electron transfer is studied. The physicochemical insight into the electrochemical activation of carbon nanotube/polymer composites was provided by transmission electron microscopy, Raman spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Dopamine, ascorbic acid, NADH, and ferricyanide are used as a model redox system for evaluating the performance of activated carbon nanotube/polymer composite electrodes. We demonstrate that polymer wrapping of carbon nanotubes is subject to defects and to partial removal during activation. Such tunable activation of electrodes would enable on-demand activation of electrodes for satisfying the needs of sensing or energy storage devices.

  19. Single-step reinforced microextraction of polycyclic aromatic hydrocarbons from soil samples using an inside needle capillary adsorption trap with electropolymerized aniline/multi-walled carbon nanotube sorbent.

    PubMed

    Ghiasvand, Ali Reza; Yazdankhah, Fatemeh

    2017-03-03

    A polyaniline/multi-wall carbon nanotubes (PANI/MWCNT) composite was electrodeposited on the interior surface of a platinized stainless steel capillary needle and used to prepare an inside needle capillary adsorption trap (INCAT) device. The platinization expanded the interior adsorbing surface of the needle and made it more porous and cohesive for nanocomposite film. The nanocomposite was characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The fabricated INCAT was fixed into a cooling capsule to fabricate a cooling-assisted INCAT (CA-INCAT) system. The CA-INCAT device was used to extract polycyclic aromatic hydrocarbons (PAHs) from solid samples followed by gas chromatography-flame ionization detection (GC-FID) determination. To obtain the best extraction efficiency, the important experimental variables were studied and optimized. Under the optimal conditions, the limits of detection (LODs) for the studied PAHs were in the range of 0.002-0.02ngg(-1). Linear dynamic ranges (LDRs) for the calibration curves were found to be 0.1-30,000ngg(-1). Relative standard deviations (RSDs%) for six replicated analysis of 1ngg(-1) PAHs were obtained 7.7-11%. The CA-INCAT-GC-FID method was successfully applied for the extraction and determination of PAHs in contaminated soil samples. The results were in agreement with those obtained by a validated ultrasound-assisted solvent extraction (UA-SE) method.

  20. Simultaneous removal of As, Cd, Cr, Cu, Ni and Zn from stormwater: experimental comparison of 11 different sorbents.

    PubMed

    Genç-Fuhrman, Hülya; Mikkelsen, Peter S; Ledin, Anna

    2007-02-01

    The potential of using alumina, activated bauxsol-coated sand (ABCS), bark, bauxsol-coated sand (BCS), fly ash (FA), granulated activated carbon (GAC), granulated ferric hydroxide (GFH), iron oxide-coated sand (IOCS), natural zeolite (NZ), sand, and spinel (MgAl(2)O(4)) as sorbents for removing heavy metals from stormwater are investigated in the present study. The ability of the sorbents to remove a mixture of As, Cd, Cr, Cu, Ni and Zn from synthetic stormwater samples were evaluated in batch tests at a starting pH of 6.5. The metal speciation and saturation data is obtained using the PHREEQ-C geochemical model and used to elucidate the sorption data. It is found that BCS, FA, and spinel have significantly higher affinity towards heavy metals mainly present as cationic or non-charged species (i.e. Cd, Cu, Ni and Zn) compared to those present as anionic species (i.e. As and Cr). However, IOCS, NZ and sand have higher affinity towards As and Cr, while alumina has equally high affinity to all tested heavy metals. The Freundlich isotherm model is found to fit the data in many cases, but ill fitted results are also observed, especially for FA, BCS and GAC, possibly due to leaching of some metals from the sorbents (i.e. for FA) and oversaturated conditions making precipitation the dominant removal mechanism over sorption in batches with high heavy metal concentrations and pH. Calculated sorption constants (i.e. K(d)) are used to compare the overall heavy metal removal efficiency of the sorbents, which in a decreasing order are found to be: alumina, BCS, GFH, FA, GAC, spinel, ABCS, IOCS, NZ, bark, and sand. These findings are significant for future development of secondary filters for removal of dissolved heavy metals from stormwater runoff under realistic competitive conditions in terms of initial heavy metal concentrations, pH and ionic strength.

  1. Comparison of CaO-based synthetic CO{sub 2} sorbents under realistic calcination conditions

    SciTech Connect

    Gemma Grasa; Belen Gonzalez; Monica Alonso; J. Carlos Abanades

    2007-12-15

    Several concepts to capture CO{sub 2} in power plants and hydrogen generation plants are under development using CaO as regenerable sorbent. The drastic decay in sorbent capture capacity of CaO obtained through calcination of natural sources of CaCO{sub 3} (limestones or dolomites) justifies the search of synthetic sorbents that aim to overcome this decay in capture capacity. We have reviewed some of the recent literature on the subject and tested some of the proposed sorbents under comparable conditions. Our results confirm the good performance of some of these synthetic sorbents under mild conditions and/or long carbonation times used in the original references. However, we show that these sorbents deactivate also very quickly when realistic regeneration conditions (high temperatures for calcination at high partial pressures of CO{sub 2}) are used in the laboratory test. We conclude that none of the reviewed sorbents have a chance to compete with the performance of natural limestones, of much lower cost. 24 refs., 4 figs.

  2. Surface Functionalized Nanostructured Ceramic Sorbents for the Effective Collection and Recovery of Uranium from Seawater

    SciTech Connect

    Chouyyok, Wilaiwan; Pittman, Jonathan W.; Warner, Marvin G.; Nell, Kara M.; Clubb, Donald C.; Gill, Gary A.; Addleman, Raymond S.

    2016-05-02

    The ability to collect uranium from seawater offers the potential for a nearly limitless fuel supply for nuclear energy. We evaluated the use of functionalized nanostructured sorbents for the collection and recovery of uranium from seawater. Extraction of trace minerals from seawater and brines is challenging due to the high ionic strength of seawater, low mineral concentrations, and fouling of surfaces over time. We demonstrate that rationally assembled sorbent materials that integrate high affinity surface chemistry and high surface area nanostructures into an application relevant micro/macro structure enables collection performance that far exceeds typical sorbent materials. High surface area nanostructured silica with surface chemistries composed of phosphonic acid, phosphonates, 3,4 hydroxypyridinone, and EDTA showed superior performance for uranium collection. A few phosphorous-based commercial resins, specifically Diphonix and Ln Resin, also performed well. We demonstrate an effective and environmentally benign method of stripping the uranium from the high affinity sorbents using inexpensive nontoxic carbonate solutions. The cyclic use of preferred sorbents and acidic reconditioning of materials was shown to improve performance. Composite thin films composed of the nanostructured sorbents and a porous polymer binder are shown to have excellent kinetics and good capacity while providing an effective processing configuration for trace mineral recovery from solutions. Initial work using the composite thin films shows significant improvements in processing capacity over the previously reported sorbent materials.

  3. DEVELOPMENT OF ACTIVATED CARBONS FROM COAL COMBUSTION BY-PRODUCTS

    SciTech Connect

    Harold H. Schobert; M. Mercedes Maroto-Valer; Zhe Lu

    2003-09-30

    The increasing role of coal as a source of energy in the 21st century will demand environmental and cost-effective strategies for the use of coal combustion by-products (CCBPs), mainly unburned carbon in fly ash. Unburned carbon is nowadays regarded as a waste product and its fate is mainly disposal, due to the present lack of efficient routes for its utilization. However, unburned carbon is a potential precursor for the production of adsorbent carbons, since it has gone through a devolatilization process while in the combustor, and therefore, only requires to be activated. Accordingly, the principal objective of this work was to characterize and utilize the unburned carbon in fly ash for the production of activated carbons. The unburned carbon samples were collected from different combustion systems, including pulverized utility boilers, a utility cyclone, a stoker, and a fluidized bed combustor. LOI (loss-on-ignition), proximate, ultimate, and petrographic analyses were conducted, and the surface areas of the samples were characterized by N2 adsorption isotherms at 77K. The LOIs of the unburned carbon samples varied between 21.79-84.52%. The proximate analyses showed that all the samples had very low moisture contents (0.17 to 3.39 wt %), while the volatile matter contents varied between 0.45 to 24.82 wt%. The elemental analyses show that all the unburned carbon samples consist mainly of carbon with very little hydrogen, nitrogen, sulfur and oxygen In addition, the potential use of unburned carbon as precursor for activated carbon (AC) was investigated. Activated carbons with specific surface area up to 1075m{sup 2}/g were produced from the unburned carbon. The porosity of the resultant activated carbons was related to the properties of the unburned carbon feedstock and the activation conditions used. It was found that not all the unburned carbon samples are equally suited for activation, and furthermore, their potential as activated carbons precursors could be

  4. Superhydrophobic activated carbon-coated sponges for separation and absorption.

    PubMed

    Sun, Hanxue; Li, An; Zhu, Zhaoqi; Liang, Weidong; Zhao, Xinhong; La, Peiqing; Deng, Weiqiao

    2013-06-01

    Highly porous activated carbon with a large surface area and pore volume was synthesized by KOH activation using commercially available activated carbon as a precursor. By modification with polydimethylsiloxane (PDMS), highly porous activated carbon showed superhydrophobicity with a water contact angle of 163.6°. The changes in wettability of PDMS- treated highly porous activated carbon were attributed to the deposition of a low-surface-energy silicon coating onto activated carbon (confirmed by X-ray photoelectron spectroscopy), which had microporous characteristics (confirmed by XRD, SEM, and TEM analyses). Using an easy dip-coating method, superhydrophobic activated carbon-coated sponges were also fabricated; those exhibited excellent absorption selectivity for the removal of a wide range of organics and oils from water, and also recyclability, thus showing great potential as efficient absorbents for the large-scale removal of organic contaminants or oil spills from water.

  5. Recent Data Analysis of Carbon ACtivation

    NASA Astrophysics Data System (ADS)

    Jiang, Hui Ming; Smith, Elizabeth; Padalino, Stephen; Baumgart, Leigh; Suny Geneseooltz, Katie; Colburn, Robyn; Fuschino, Julia

    2002-10-01

    A method for measuring tertiary neutrons produced in Inertial Confinement Fusion reactions has been developed using carbon activation. Ultra pure samples of carbon, free from positron-emitting contaminants must be used in the detection. Our primary goal has been to reduce the contamination level by refining purification and packaging procedures. This process involves baking the disks in a vacuum oven to 1000¢XC @ 200 microns for a prescribed bake time without exposing the disks to nitrogen in the air which is a major contaminant. Recent experiments were conducted to determine the optimal bake time for purification. Disks were baked for varying times, from one hour to five hours, and then exposed to high-neutron-yield ( 5 x 1013) shots on OMEGA. Data collected was normalized to the same time interval and the same primary neutron yield, and no significant difference in the number of background counts was seen. Experimental results also indicated that disks that were exposed to air for short time intervals showed a significant increase in the number of contamination counts. This further supports our findings that the gaseous diffusion through graphite disks is very high. Experimental results of these findings will be presented. Research funded in part by the United States Department of Energy.

  6. Activated Carbon Composites for Air Separation

    SciTech Connect

    Baker, Frederick S; Contescu, Cristian I; Tsouris, Costas; Burchell, Timothy D

    2011-09-01

    Coal-derived synthesis gas is a potential major source of hydrogen for fuel cells. Oxygen-blown coal gasification is an efficient approach to achieving the goal of producing hydrogen from coal, but a cost-effective means of enriching O2 concentration in air is required. A key objective of this project is to assess the utility of a system that exploits porous carbon materials and electrical swing adsorption to produce an O2-enriched air stream for coal gasification. As a complement to O2 and N2 adsorption measurements, CO2 was used as a more sensitive probe molecule for the characterization of molecular sieving effects. To further enhance the potential of activated carbon composite materials for air separation, work was implemented on incorporating a novel twist into the system; namely the addition of a magnetic field to influence O2 adsorption, which is accompanied by a transition between the paramagnetic and diamagnetic states. The preliminary findings in this respect are discussed.

  7. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    NASA Astrophysics Data System (ADS)

    Byamba-Ochir, Narandalai; Shim, Wang Geun; Balathanigaimani, M. S.; Moon, Hee

    2016-08-01

    Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816-2063 m2/g and of 0.55-1.61 cm3/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  8. Reuse performance of granular-activated carbon and activated carbon fiber in catalyzed peroxymonosulfate oxidation.

    PubMed

    Yang, Shiying; Li, Lei; Xiao, Tuo; Zhang, Jun; Shao, Xueting

    2017-03-01

    Recently, activated carbon was investigated as an efficient heterogeneous metal-free catalyst to directly activate peroxymonosulfate (PMS) for degradation of organic compounds. In this paper, the reuse performance and the possible deactivation reasons of granular-activated carbon (GAC) and activated carbon fiber (ACF) in PMS activation were investigated. As results indicated, the reusability of GAC, especially in the presence of high PMS dosage, was relatively superior to ACF in catalyzed PMS oxidation of Acid Orange 7 (AO7), which is much more easily adsorbed by ACF than by GAC. Pre-oxidation experiments were studied and it was demonstrated that PMS oxidation on ACF would retard ACF's deactivation to a big extent. After pre-adsorption with AO7, the catalytic ability of both GAC and ACF evidently diminished. However, when methanol was employed to extract the AO7-spent ACF, the catalytic ability could recover quite a bit. GAC and ACF could also effectively catalyze PMS to degrade Reactive Black 5 (RB5), which is very difficult to be adsorbed even by ACF, but both GAC and ACF have poor reuse performance for RB5 degradation. The original organic compounds or intermediate products adsorbed by GAC or ACF would be possibly responsible for the deactivation.

  9. Enhanced adsorption of humic acids on ordered mesoporous carbon compared with microporous activated carbon.

    PubMed

    Liu, Fengling; Xu, Zhaoyi; Wan, Haiqin; Wan, Yuqiu; Zheng, Shourong; Zhu, Dongqiang

    2011-04-01

    Humic acids are ubiquitous in surface and underground waters and may pose potential risk to human health when present in drinking water sources. In this study, ordered mesoporous carbon was synthesized by means of a hard template method and further characterized by X-ray diffraction, N2 adsorption, transition electron microscopy, elemental analysis, and zeta-potential measurement. Batch experiments were conducted to evaluate adsorption of two humic acids from coal and soil, respectively, on the synthesized carbon. For comparison, a commercial microporous activated carbon and nonporous graphite were included as additional adsorbents; moreover, phenol was adopted as a small probe adsorbate. Pore size distribution characterization showed that the synthesized carbon had ordered mesoporous structure, whereas the activated carbon was composed mainly of micropores with a much broader pore size distribution. Accordingly, adsorption of the two humic acids was substantially lower on the activated carbon than on the synthesized carbon, because of the size-exclusion effect. In contrast, the synthesized carbon and activated carbon showed comparable adsorption for phenol when the size-exclusion effect was not in operation. Additionally, we verified by size-exclusion chromatography studies that the synthesized carbon exhibited greater adsorption for the large humic acid fraction than the activated carbon. The pH dependence of adsorption on the three carbonaceous adsorbents was also compared between the two test humic acids. The findings highlight the potential of using ordered mesoporous carbon as a superior adsorbent for the removal of humic acids.

  10. Characterization of Activated Carbons from Oil-Palm Shell by CO2 Activation with No Holding Carbonization Temperature

    PubMed Central

    Herawan, S. G.; Hadi, M. S.; Ayob, Md. R.; Putra, A.

    2013-01-01

    Activated carbons can be produced from different precursors, including coals of different ranks, and lignocellulosic materials, by physical or chemical activation processes. The objective of this paper is to characterize oil-palm shells, as a biomass byproduct from palm-oil mills which were converted into activated carbons by nitrogen pyrolysis followed by CO2 activation. The effects of no holding peak pyrolysis temperature on the physical characteristics of the activated carbons are studied. The BET surface area of the activated carbon is investigated using N2 adsorption at 77 K with selected temperatures of 500, 600, and 700°C. These pyrolysis conditions for preparing the activated carbons are found to yield higher BET surface area at a pyrolysis temperature of 700°C compared to selected commercial activated carbon. The activated carbons thus result in well-developed porosities and predominantly microporosities. By using this activation method, significant improvement can be obtained in the surface characteristics of the activated carbons. Thus this study shows that the preparation time can be shortened while better results of activated carbon can be produced. PMID:23737721

  11. Characterization of activated carbons from oil-palm shell by CO2 activation with no holding carbonization temperature.

    PubMed

    Herawan, S G; Hadi, M S; Ayob, Md R; Putra, A

    2013-01-01

    Activated carbons can be produced from different precursors, including coals of different ranks, and lignocellulosic materials, by physical or chemical activation processes. The objective of this paper is to characterize oil-palm shells, as a biomass byproduct from palm-oil mills which were converted into activated carbons by nitrogen pyrolysis followed by CO2 activation. The effects of no holding peak pyrolysis temperature on the physical characteristics of the activated carbons are studied. The BET surface area of the activated carbon is investigated using N2 adsorption at 77 K with selected temperatures of 500, 600, and 700°C. These pyrolysis conditions for preparing the activated carbons are found to yield higher BET surface area at a pyrolysis temperature of 700°C compared to selected commercial activated carbon. The activated carbons thus result in well-developed porosities and predominantly microporosities. By using this activation method, significant improvement can be obtained in the surface characteristics of the activated carbons. Thus this study shows that the preparation time can be shortened while better results of activated carbon can be produced.

  12. FIELD TEST PROGRAM FOR EVALUATION OF SORBENT INJECTION FOR MERCURY CONTROL

    SciTech Connect

    Sharon Sjostrom

    2004-02-12

    The power industry in the U.S. is faced with meeting new regulations to reduce the emissions of mercury compounds from coal-fired plants. These regulations are directed at the existing fleet of nearly 1,100 boilers. These plants are relatively old with an average age of over 40 years. Although most of these units are capable of operating for many additional years, there is a desire to minimize large capital expenditures because of the reduced (and unknown) remaining life of the plant to amortize the project. Injecting a sorbent such as powdered activated carbon into the flue gas represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. The overall objective of this test program described in this quarterly report is to evaluate the capabilities of activated carbon injection at four plants with configurations that together represent 78% of the existing coal-fired generation plants. This technology was successfully evaluated in NETL's Phase I tests at scales up to 150 MW, on plants burning subbituminous and bituminous coals and with ESPs and fabric filters. The tests also identified issues that still need to be addressed, such as evaluating performance on other configurations, optimizing sorbent usage (costs), and gathering longer term operating data to address concerns about the impact of activated carbon on plant equipment and operations. The four sites identified for testing are Sunflower Electric's Holcomb Station, AmerenUE's Meramec Station, AEP's Conesville Station, and Ontario Power Generation's Nanticoke Station. This is the first quarterly report for this project. This report includes an overview of the plans for the project. Field testing is scheduled to begin next quarter. In general, quarterly reports will be used to provide project overviews, project status, and technology transfer information. Topical reports will be prepared to present detailed technical information.

  13. Silica- and germania-based dual-ligand sol-gel organic-inorganic hybrid sorbents combining superhydrophobicity and π-π interaction. The role of inorganic substrate in sol-gel capillary microextraction.

    PubMed

    Seyyal, Emre; Malik, Abdul

    2017-04-29

    Principles of sol-gel chemistry were utilized to create silica- and germania-based dual-ligand surface-bonded sol-gel coatings providing enhanced performance in capillary microextraction (CME) through a combination of ligand superhydrophobicity and π-π interaction. These organic-inorganic hybrid coatings were prepared using sol-gel precursors with bonded perfluorododecyl (PF-C12) and phenethyl (PhE) ligands. Here, the ability of the PF-C12 ligand to provide enhanced hydrophobic interaction was advantageously combined with π-π interaction capability of the PhE moiety to attain the desired sorbent performance in CME. The effect of the inorganic sorbent component on microextraction performance of was explored by comparing microextraction characteristics of silica- and germania-based sol-gel sorbents. The germania-based dual-ligand sol-gel sorbent demonstrated superior CME performance compared to its silica-based counterpart. Thermogravimetric analysis (TGA) of the created silica- and germania-based dual-ligand sol-gel sorbents suggested higher carbon loading on the germania-based sorbent. This might be indicative of more effective condensation of the organic ligand-bearing sol-gel-active chemical species to the germania-based sol-gel network (than to its silica-based counterpart) evolving in the sol solution. The type and concentration of the organic ligands were varied in the sol-gel sorbents to fine-tune extraction selectivity toward different classes of analytes. Specific extraction (SE) values were used for an objective comparison of the prepared sol-gel CME sorbents. The sorbents with higher content of PF-C12 showed remarkable affinity for aliphatic hydrocarbons. Compared to their single-ligand sol-gel counterparts, the dual-ligand sol-gel coatings demonstrated significantly superior CME performance in the extraction of alkylbenzenes, providing up to ∼65.0% higher SE values. The prepared sol-gel CME coatings provided low ng L(-1) limit of detections (LOD

  14. Selective cytopheretic inhibitory device with regional citrate anticoagulation and portable sorbent dialysis.

    PubMed

    Pino, Christopher J; Farokhrani, Amin; Lou, Liandi; Smith, Peter L; Johnston, Kimberly; Buffington, Deborah A; Humes, H David

    2013-02-01

    Selective cytopheretic inhibitory device (SCD) therapy is an immunomodulatory treatment provided by a synthetic biomimetic membrane in an extracorporeal circuit, which has shown promise in preclinical large animal models of severe sepsis as well as in clinical trials treating patients with acute kidney injury and multiple organ failure. During SCD therapy, citrate is administered to lower ionized calcium levels in blood for anticoagulation and inhibition of leukocyte activation. Historically, citrate has been known to interfere with sorbent dialysis, therefore, posing a potential issue for the use of SCD therapy with a portable dialysis system. This sorbent dialysis SCD (sorbent SCD) would be well suited for battlefield and natural disaster applications where the water supply for standard dialysis is limited, and the types of injuries in those settings would benefit from SCD therapy. In order to explore the compatibility of sorbent and SCD technologies, a uremic porcine model was tested with the Allient sorbent dialysis system (Renal Solutions Incorporated, Fresenius Medical Care, Warrendale, PA, USA) and concurrent SCD therapy with regional citrate anticoagulation. The hypothesis to be assessed was whether the citrate load required by the SCD could be metabolized prior to recirculation from systemic blood back into the therapeutic circuit. Despite the fact that the sorbent SCD maintained urea clearance without any adverse hematologic events, citrate load for SCD therapy caused an interaction with the sorbent column resulting in elevated, potentially toxic aluminum levels in dialysate and in systemic blood. Alternative strategies to implement sorbent-SCD therapy will be required, including development of alternate urease-sorbent column binding chemistry or further changes to the sorbent-SCD therapeutic circuit along with determining the minimum citrate concentration required for efficacious SCD treatment.

  15. Exploring molecular sieve capabilities of activated carbon fibers to reduce the impact of NOM preloading on trichloroethylene adsorption

    SciTech Connect

    Tanju Karanfil; Seyed A. Dastgheib; Dina Mauldin

    2006-02-15

    Adsorption of trichloroethylene (TCE) by two activated carbon fibers ACF10 and ACF20H and two granular activated carbons, coal-based F400 and Macro preloaded with hydrophobic and transphilic fractions of natural organic matter (NOM) was examined. ACF10, the most microporous activated carbon used in this study, had over 90% of its pore volume in pores smaller than 10 {angstrom}. It also had the highest volume in pores 5-8 {angstrom}, which is the optimum pore size region for TCE adsorption, among the four activated carbons. Adsorption of NOM fractions by ACF10 was, in general, negligible. Therefore, ACF10, functioning as a molecular sieve during preloading, exhibited the least NOM uptake for each fraction, and subsequently the highest TCE adsorption. The other three sorbents had wider pore size distributions, including high volumes in pores larger than 10 {angstrom}, where NOM molecules can adsorb. As a result, they showed a higher degree of uptake for all NOM fractions, and subsequently lower adsorption capacities for TCE, as compared to ACF10. The results obtained in this study showed that understanding the interplay between the optimum pore size region for the adsorption of target synthetic organic contaminant (SOC) and the pore size region for the adsorption of NOM molecules is important for controlling NOM-SOC competitions. Experiments with different NOM fractions indicated that the degree of NOM loading is important in terms of preloading effects; however the way that the carbon pores are filled and loaded by different NOM fractions can be different and may create an additional negative impact on TCE adsorption. 40 refs., 3 figs., 2 tabs.

  16. Photopatternable sorbent and functionalized films

    DOEpatents

    Grate, Jay W.; Nelson, David A.

    2006-01-31

    A composition containing a polymer, a crosslinker and a photo-activatable catalyst is placed on a substrate. The composition is exposed to a predetermined pattern of light, leaving an unexposed region. The light causes the polymer to become crosslinked by hydrosilylation. A solvent is used to remove the unexposed composition from the substrate, leaving the exposed pattern to become a sorbent polymer film that will absorb a predetermined chemical species when exposed to such chemical species.

  17. Environmental carbon dioxide control

    NASA Technical Reports Server (NTRS)

    Onischak, M.; Baker, B.; Gidaspow, D.

    1974-01-01

    A study of environmental carbon dioxide control for NASA EVA missions found solid potassium carbonate to be an effective regenerable absorbent in maintaining low carbon dioxide levels. The supported sorbent was capable of repeated regeneration below 150 C without appreciable degradation. Optimum structures in the form of thin pliable sheets of carbonate, inert support and binder were developed. Interpretation of a new solid-gas pore closing model helped predict the optimum sorbent and analysis of individual sorbent sheet performance in a thin rectangular channel sorber can predict packed bed performance.

  18. Removal of lead from aqueous effluents by adsorption on coconut shell carbon.

    PubMed

    Sekhar, M Chandra

    2008-04-01

    The application of adsorption for removal of heavy metals is quite popular and activated carbon is universally used as an adsorbent. However, high cost of its preparation and regeneration has led to a search for alternative sorbents, especially in the developing countries. A number of sorbents are used to remove metals by adsorption from industrial effluents, which include insoluble starch, xanthates, modified cotton and wool, tree barks, activated carbon, plant leaves and agricultural products. Therefore, as an alternative, coconut shell carbon (CSC), a low cost sorbent derived from organic waste material, was used in the present work, for removal of lead from aqueous effluents. The results of the batch sorption studies indicated that the efficiency of lead removal by coconut shell carbon is comparable to that of commercially available activated carbon. From the kinetic and equilibrium studies, the sorptive capacity of coconut shell carbon for lead was found to be 30 mg/g. Desorption and subsequent recovery of the metal from the surface of the sorbent was successfully demonstrated. Parameters affecting the sorption were evaluated.

  19. Mercury Control with Calcium-Based Sorbents and Oxidizing Agents

    SciTech Connect

    Thomas K. Gale

    2005-07-01

    This Final Report contains the test descriptions, results, analysis, correlations, theoretical descriptions, and model derivations produced from many different investigations performed on a project funded by the U.S. Department of Energy, to investigate calcium-based sorbents and injection of oxidizing agents for the removal of mercury. Among the technologies were (a) calcium-based sorbents in general, (b) oxidant-additive sorbents developed originally at the EPA, and (c) optimized calcium/carbon synergism for mercury-removal enhancement. In addition, (d) sodium-tetrasulfide injection was found to effectively capture both forms of mercury across baghouses and ESPs, and has since been demonstrated at a slipstream treating PRB coal. It has been shown that sodium-tetrasulfide had little impact on the foam index of PRB flyash, which may indicate that sodium-tetrasulfide injection could be used at power plants without affecting flyash sales. Another technology, (e) coal blending, was shown to be an effective means of increasing mercury removal, by optimizing the concentration of calcium and carbon in the flyash. In addition to the investigation and validation of multiple mercury-control technologies (a through e above), important fundamental mechanism governing mercury kinetics in flue gas were elucidated. For example, it was shown, for the range of chlorine and unburned-carbon (UBC) concentrations in coal-fired utilities, that chlorine has much less effect on mercury oxidation and removal than UBC in the flyash. Unburned carbon enhances mercury oxidation in the flue gas by reacting with HCl to form chlorinated-carbon sites, which then react with elemental mercury to form mercuric chloride, which subsequently desorbs back into the flue gas. Calcium was found to enhance mercury removal by stabilizing the oxidized mercury formed on carbon surfaces. Finally, a model was developed to describe these mercury adsorption, desorption, oxidation, and removal mechanisms, including

  20. [Effects of different fertilizer application on soil active organic carbon].

    PubMed

    Zhang, Rui; Zhang, Gui-Long; Ji, Yan-Yan; Li, Gang; Chang, Hong; Yang, Dian-Lin

    2013-01-01

    The variation characteristics of the content and components of soil active organic carbon under different fertilizer application were investigated in samples of calcareous fluvo-aquic soil from a field experiment growing winter wheat and summer maize in rotation in the North China Plain. The results showed that RF (recommended fertilization), CF (conventional fertilization) and NPK (mineral fertilizer alone) significantly increased the content of soil dissolved organic carbon and easily oxidized organic carbon by 24.92-38.63 mg x kg(-1) and 0.94-0.58 mg x kg(-1) respectively compared to CK (unfertilized control). The soil dissolved organic carbon content under OM (organic manure) increased greater than those under NPK and single fertilization, soil easily oxidized organic carbon content under OM and NPK increased greater than that under single chemical fertilization. OM and NPK showed no significant role in promoting the soil microbial biomass carbon, but combined application of OM and NPK significantly increased the soil microbial biomass carbon content by 36.06% and 20.69%, respectively. Soil easily oxidized organic carbon, dissolved organic carbon and microbial biomass carbon accounted for 8.41% - 14.83%, 0.47% - 0.70% and 0.89% - 1.20% of the total organic carbon (TOC), respectively. According to the results, the fertilizer application significantly increased the proportion of soil dissolved organic carbon and easily oxidized organic carbon, but there was no significant difference in the increasing extent of dissolved organic carbon. The RF and CF increased the proportion of soil easily oxidized organic carbon greater than OM or NPK, and significantly increased the proportion of microbial biomass carbon. OM or RF had no significant effect on the proportion of microbial biomass carbon. Therefore, in the field experiment, appropriate application of organic manure and chemical fertilizers played an important role for the increase of soil active organic carbon

  1. Advanced low-temperature sorbents

    SciTech Connect

    Ayala, R.E.; Venkataramani, V.S.; Abbasian, J.; Hill, A.H.

    1995-12-01

    A number of promising technologies are currently being optimized for coal-based power generation, including the Integrated-Gasification Combined Cycle (IGCC) system. If IGCC is to be used successfully for power generation, an economic and efficient way must be found to remove the contaminants, particularly sulfur species, found in coal gas. Except for the hot gas desulfurization system, all major components of IGCC are commercially available or have been shown to meet system requirements. Over the last two decades, the U.S. Department of Energy/Morgantown Energy Technology Center (DOE/METC) has sponsored development of various configurations of high-temperature desulfurization systems including fixed-bed, moving-bed, transport-bed, and fluidized-bed systems. Because of their mode of operation and requirements for sorbent manufacturing, the fixed-bed systems can generally use the same materials as moving-bed configurations, i.e., pelletized or extruded sorbents, while fluidized-bed (circulating or bubbling configurations) and transport reactor configurations use materials generally described as agglomerated or granulated.The objective of this program is to remove hydrogen sulfides from coal gas using sorbent materials.

  2. The chemical precipitation of nickel on ion exchangers and active carbons

    NASA Astrophysics Data System (ADS)

    Khorol'Skaya, S. V.; Zolotukhina, E. V.; Polyanskii, L. N.; Peshkov, S. V.; Kravchenko, T. A.; Krysanov, V. A.

    2010-12-01

    The chemical precipitation of nickel in the form of poorly soluble precipitates in ion exchanger matrices and on active carbons from solutions of nickel chloride and chemical nickel plating electrolytes was studied. The sorption of nickel ions from a solution of nickel chloride occurs most effectively on Purolite D24002 macroporous chelate forming ion exchanger, KU-23-15/100 sulfo cation exchanger, and KU-2-8 gel sulfo cation exchanger. Nickel enters sulfo cation exchangers in the form of counterions, and is adsorbed on Purolite D24002 largely because of complex formation. The subsequent precipitation of nickel in the solid state in matrix pores liberates ionogenic centers, which allows repeated sorption cycles to be performed. After three chemical precipitation cycles under static conditions, the amount of nickel is higher by 170-250% than the ion exchange capacity of the sorbents. The electrolyte of chemical nickel plating contains nickel predominantly in the form of negatively charged and neutral complexes with glycine, which cannot form bonds with the matrices under study. It is therefore reasonable to perform sorption at decreased solution pH values.

  3. Equilibrium and dynamic study on hexavalent chromium adsorption onto activated carbon.

    PubMed

    Di Natale, F; Erto, A; Lancia, A; Musmarra, D

    2015-01-08

    In this work, the results of equilibrium and dynamic adsorption tests of hexavalent chromium, Cr (VI), on activated carbon are presented. Adsorption isotherms were determined at different levels of pH and temperature. Dynamic tests were carried out in terms of breakthrough curves of lab-scale fixed bed column at different pH, inlet concentration and flow rate. Both the adsorption isotherms and the breakthrough curves showed non-linear and unconventional trends. The experimental results revealed that chromium speciation played a key role in the adsorption process, also for the occurrence of Cr(VI)-to-Cr(III) reduction reactions. Equilibrium tests were interpreted in light of a multi-component Langmuir model supported by ion speciation analysis. For the interpretation of the adsorption dynamic tests, a mass transfer model was proposed. Dynamic tests at pH 11 were well described considering the external mass transfer as the rate controlling step. Differently, for dynamic tests at pH 6 the same model provided a satisfying description of the experimental breakthrough curves only until a sorbent coverage around 1.6mgg(-1). Above this level, a marked reduction of the breakthrough curve slope was observed in response to a transition to an inter-particle adsorption mechanism.

  4. Carbon dioxide separation using adsorption with steam regeneration

    DOEpatents

    Elliott, Jeannine Elizabeth; Copeland, Robert James; Leta, Daniel P.; McCall, Patrick P.; Bai, Chuansheng; DeRites, Bruce A.

    2016-11-29

    A process for separating a carbon dioxide from a gas stream is disclosed. The process can include passing the gas stream over a sorbent that adsorbs the carbon dioxide by concentration swing adsorption and adsorptive displacement. The sorbent can be regenerated and the carbon dioxide recaptured by desorbing the carbon dioxide from the sorbent using concentration swing adsorption and desorptive displacement. A carbon dioxide separation system is also disclosed. Neither the system nor the process rely on temperature swing or pressure swing adsorption.

  5. Development and Evaluation of Nanoscale Sorbents for Mercury Capture from Warm Fuel Gas

    SciTech Connect

    Raja A. Jadhav; Howard Meyer; Slawomir Winecki

    2006-03-01

    Several nanocrystalline sorbents were synthesized by GTI's subcontractor NanoScale Materials, Inc. (NanoScale) and submitted to GTI for evaluation. A total of seventeen sorbent formulations were synthesized and characterized by NanoScale, including four existing sorbent formulations (NanoActive{trademark} TiO{sub 2}, NanoActive CeO{sub 2}, NanoActive ZnO, and NanoActive CuO), three developmental nanocrystalline metal oxides (MnO{sub 2}, MoO{sub 3}, and Cr{sub 2}O{sub 3}), and ten supported forms of metal oxides. These sorbents were characterized for physical and chemical properties using a variety of analytical equipments, which confirmed their nanocrystalline structure.

  6. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    PubMed

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

  7. Lime-Based Sorbents for High-Temperature CO2 Capture—A Review of Sorbent Modification Methods

    PubMed Central

    Manovic, Vasilije; Anthony, Edward J.

    2010-01-01

    This paper presents a review of the research on CO2 capture by lime-based looping cycles undertaken at CanmetENERGY’s (Ottawa, Canada) research laboratories. This is a new and very promising technology that may help in mitigation of global warming and climate change caused primarily by the use of fossil fuels. The intensity of the anticipated changes urgently requires solutions such as more cost-effective technologies for CO2 capture. This new technology is based on the use of lime-based sorbents in a dual fluidized bed combustion (FBC) reactor which contains a carbonator—a unit for CO2 capture, and a calciner—a unit for CaO regeneration. However, even though natural materials are cheap and abundant and very good candidates as solid CO2 carriers, their performance in a practical system still shows significant limitations. These limitations include rapid loss of activity during the capture cycles, which is a result of sintering, attrition, and consequent elutriation from FBC reactors. Therefore, research on sorbent performance is critical and this paper reviews some of the promising ways to overcome these shortcomings. It is shown that reactivation by steam/water, thermal pre-treatment, and doping simultaneously with sorbent reforming and pelletization are promising potential solutions to reduce the loss of activity of these sorbents over multiple cycles of use. PMID:20948952

  8. JPL Activated Carbon Treatment System (ACTS) for sewage

    NASA Technical Reports Server (NTRS)

    1976-01-01

    An Activated Carbon Treatment System (ACTS) was developed for sewage treatment and is being applied to a one-million gallon per day sewage treatment pilot plant in Orange County California. Activities reported include pyrolysis and activation of carbon-sewage sludge, and activated carbon treatment of sewage to meet ocean discharge standards. The ACTS Sewage treatment operations include carbon-sewage treatment, primary and secondary clarifiers, gravity (multi-media) filter, filter press dewatering, flash drying of carbon-sewage filter cake, and sludge pyrolysis and activation. Tests were conducted on a laboratory scale, 10,000 gallon per day demonstration plant and pilot test equipment. Preliminary economic studies are favorable to the ACTS process relative to activated sludge treatment for a 175,000,000 gallon per day sewage treatment plant.

  9. Activated Carbon Modified with Copper for Adsorption of Propanethiol

    PubMed Central

    Moreno-Piraján, Juan Carlos; Tirano, Joaquín; Salamanca, Brisa; Giraldo, Liliana

    2010-01-01

    Activated carbons were characterized texturally and chemically before and after treatment, using surface area determination in the BET model, Boehm titration, TPR, DRX and immersion calorimetry. The adsorption capacity and the kinetics of sulphur compound removal were determined by gas chromatography. It was established that the propanethiol retention capacity is dependent on the number of oxygenated groups generated on the activated carbon surface and that activated carbon modified with CuO at 0.25 M shows the highest retention of propanethiol. Additionally is proposed a mechanism of decomposition of propenothiol with carbon-copper system. PMID:20479992

  10. CO{sub 2} capture from flue gases using three Ca-based sorbents in a fluidized bed reactor

    SciTech Connect

    Li, Z.S.; Fang, F.; Cai, N.S.

    2009-06-15

    Abstract: Experiments of CO{sub 2} capture and sorbent regeneration characteristics of limestone, dolomite, and CaO/Ca{sub 1}2Al{sub 14}O{sub 3}3 at high temperature were investigated in a thermogravimetric analyzer (TGA) and a fluidized bed reactor. The effect of reactivity decay of limestone, dolomite, and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents on CO{sub 2} capture and sorbent regeneration processes was studied. The experimental results indicated that the operation time of high efficient CO{sub 2} capture stage declined continuously with increasing of the cyclic number due to the loss of the sorbent activity, and the final CO{sub 2} capture efficiency would remain nearly constant, due to the sorbent already reaching the final residual capture capacity. After the CO{sub 2} capture step, the Ca-based sorbents need to be regenerated to be used for a subsequent cycle, and the multiple calcination processes of Ca-based sorbent under different calcination conditions are studied and discussed. Reactivity loss of limestone, dolomite and CaO/Ca{sub 12}Al{sub 14}O{sub 3}3 sorbents from a fluidized bed reactor at both mild and severe calcination conditions was compared with the TGA data. At mild calcination conditions, TGA results of sorbent reactivity loss were similar to the experimental results of fluidized bed reactor for three sorbents at 850 degrees C calcination temperature, and this indicated that TGA experimental results can be used as a reference to predict sorbent reactivity loss behavior in fluidized bed reactor. At severe calcination condition, sorbent reactivity loss behavior for limestone and dolomite from TGA compare well with the result from a fluidized bed reactor.

  11. Tailor-Made Core-Shell CaO/TiO2-Al2O3 Architecture as a High-Capacity and Long-Life CO2 Sorbent.

    PubMed

    Peng, Weiwei; Xu, Zuwei; Luo, Cong; Zhao, Haibo

    2015-07-07

    CaO-based sorbents are widely used for CO2 capture, steam methane reforming, and gasification enhancement, but the sorbents suffer from rapid deactivation during successive carbonation/calcination cycles. This research proposes a novel self-assembly template synthesis (SATS) method to prepare a hierarchical structure CaO-based sorbent, Ca-rich, Al2O3-supported, and TiO2-stabilized in a core-shell microarchitecture (CaO/TiO2-Al2O3). The cyclic CO2 capture performance of CaO/TiO2-Al2O3 is compared with those of pure CaO and CaO/Al2O3. CaO/TiO2-Al2O3 sorbent achieved superior and durable CO2 capture capacity of 0.52 g CO2/g sorbent after 20 cycles under the mild calcination condition and retained a high-capacity and long-life performance of 0.44 g CO2/g sorbent after 104 cycles under the severe calcination condition, much higher than those of CaO and CaO/Al2O3. The microstructure characterization of CaO/TiO2-Al2O3 confirmed that the core-shell structure of composite support effectively inhibited the reaction between active component (CaO particles) and main support (Al2O3 particles) by TiO2 addition, which contributed to its properties of high reactivity, thermal stability, mechanical strength, and resistance to agglomeration and sintering.

  12. Hot Coal Gas Desulfurization with manganese-based sorbents. Second [quarterly] technical report, December 1, 1992--March 1, 1993

    SciTech Connect

    Hepworth, M.T.

    1993-03-01

    At present, the focus of work being performed on Hot Coal Gas Desulfurization is primarily in the use of zinc ferrite and zinc titanate sorbents; however studies at the US Steel Fundamental Research Laboratories in Monroeville, PA, by E. T. Turkdogan indicate that an alternate sorbent, manganese dioxide-containing ore in mixture with alumina (75 wt % ore + 25 wt % Al{sub 2}O{sub 3}) may be a preferable alternative to zinc-based sorbents. A significant domestic source of manganese in Minnesota is being explored for an in situ leach process which has potential for producing large tonnages of solutions which may be ideal for precipitation and recovery of pure manganese as a carbonate in a reactive form. In the current program the following studies will be addressed: Preparation of manganese sorbent pellets and characterization tests on pellets for strength and surface area; analysis of the thermodynamics and kinetics of sulfur removal from hot fuel gases by individual sorbent pellets (loading tests) by thermogravimetric testing; regeneration tests via TGA on individual sorbent pellets by oxidation; and bench-scale testing on sorbent beds in a two-inch diameter reactor. The developed information will be of value to METC in its determination of whether or not a manganese-based regenerable sorbent holds real promise for sulfur cleanup of hot fuel gases. This information is necessary prior to pilot-scale testing leading to commercial development is undertaken.

  13. Magnetic pollen grains as sorbents for facile removal of organic pollutants in aqueous media.

    PubMed

    Thio, Beng Joo Reginald; Clark, Kristin K; Keller, Arturo A

    2011-10-30

    Plant materials have long been demonstrated to sorb organic compounds. However, there are no known reports about pollen grains acting as sorbents to remove hydrophobic organic compounds (HOCs) such as pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from contaminated waters. We report a facile and effective method to remove HOCs from water using magnetized short ragweed (Ambrosia artemisiifolia) pollen grains. We dispersed the magnetized pollen grains in two different water samples - deionized (DI) and natural storm water to mimic real environmental conditions likely to be encountered during treatment. The magnetized pollen grains were readily separated from the aqueous media via a magnetic field after adsorption of the HOCs. We measured the adsorption of five representative HOCs (acenaphthene, phenanthrene, atrazine, diuron, and lindane) onto magnetized ragweed pollen in different aqueous matrices. We demonstrate that the adsorption capacity of the magnetized ragweed pollen can be regenerated to a large extent for reuse as a sorbent. Our results also indicate that the magnetized pollen grains are as effective as activated carbon (AC) in removing HOCs from both types of contaminated waters. The high HOC sorption of the ragweed pollen allows it to have potential remediation application in the field under realistic conditions.

  14. Metal-Organic Frameworks: Literature Survey and Recommendation of Potential Sorbent Materials

    SciTech Connect

    Baumann, T F

    2010-04-29

    Metal-organic frameworks (MOFs) are a special type of porous material with a number of unique properties, including exceptionally high surface areas, large internal pore volumes (void space) and tunable pore sizes. These materials are prepared through the assembly of molecular building blocks into ordered three-dimensional structures. The bulk properties of the MOF are determined by the nature of the building blocks and, as such, these materials can be designed with special characteristics that cannot be realized in other sorbent materials, like activated carbons. For example, MOFs can be constructed with binding sites or pockets that can exhibit selectivity for specific analytes. Alternatively, the framework can be engineered to undergo reversible dimensional changes (or 'breathing') upon interaction with an analyte, effectively trapping the molecule of interest in the lattice structure. In this report, we have surveyed the 4000 different MOF structures reported in the open literature and provided recommendations for specific MOF materials that should be investigated as sorbents for this project.

  15. Synthesis of nanostructured hybrid sorbent materials using organosilane self-assembly on mesoporous ceramic oxides

    SciTech Connect

    Fryxell, Glen E.

    2007-01-30

    The single most important factor in determining quality of life in human society is the availability of pure, clean drinking water. Wars have been fought, and will continue to be fought, over access and control of clean water. Drinking water has two major classes of contamination, biological contamination and chemical contamination. Bacterial contamination can be dealt with by a number of well-established technologies (e.g. chlorination, ozone, UV, etc.), but chemical contamination is a somewhat more challenging target. Common organic contaminants, such as pesticides, agricultural chemicals, industrial solvents, and fuels can be removed by treatment with UV/ozone, activated carbon or plasma technologies. Toxic heavy metals like mercury, lead and cadmium can be partially addressed by using traditional sorbent materials like alumina, but these materials bind metal ions non-specifically and can easily be saturated with harmless, ubiquitous species like calcium, magnesium and zinc (which are actually nutrients, and don’t need to be removed). Another weakness of these traditional sorbent materials is that metal ion sorption to a ceramic oxide surface is a reversible process, meaning they can easily desorb back into the drinking water supply.

  16. Preparation of nitrogen-enriched activated carbons from brown coal

    SciTech Connect

    Robert Pietrzak; Helena Wachowska; Piotr Nowicki

    2006-05-15

    Nitrogen-enriched activated carbons were prepared from a Polish brown coal. Nitrogen was introduced from urea at 350{sup o}C in an oxidizing atmosphere both to carbonizates obtained at 500-700{sup o}C and to activated carbons prepared from them. The activation was performed at 800{sup o}C with KOH in argon. It has been observed that the carbonization temperature determines the amount of nitrogen that is incorporated (DC5U, 8.4 wt % N{sup daf}; DC6U, 6.3 wt % N{sup daf}; and DC7U, 5.4 wt % N{sup daf}). X-ray photoelectron spectroscopy (XPS) measurements have shown that nitrogen introduced both at the stage of carbonizates and at the stage of activated carbons occurs mainly as -6, -5, and imine, amine and amide groups. On the other hand, the activation of carbons enriched with nitrogen results in the formation of pyridonic nitrogen and N-Q. The introduction of nitrogen at the activated carbon stage leads to a slight decrease in surface area. It has been proven that the most effective way of preparing microporous activated carbons enriched with nitrogen to a considerable extent and having high surface area ({approximately} 3000 m{sup 2}/g) is the following: carbonization - activation - reaction with urea. 40 refs., 1 fig., 6 tabs.

  17. SCALE-UP OF ADVANCED HOT-GAS DESULFURIZATION SORBENTS

    SciTech Connect

    K. JOTHIMURUGESAN; S.K. GANGWAL

    1998-03-01

    The objective of this study was to develop advanced regenerable sorbents for hot gas desulfurization in IGCC systems. The specific objective was to develop durable advanced sorbents that demonstrate a strong resistance to attrition and chemical deactivation, and high sulfidation activity at temperatures as low as 343 C (650 F). Twenty sorbents were synthesized in this work. Details of the preparation technique and the formulations are proprietary, pending a patent application, thus no details regarding the technique are divulged in this report. Sulfidations were conducted with a simulated gas containing (vol %) 10 H{sub 2}, 15 CO, 5 CO{sub 2}, 0.4-1 H{sub 2}S, 15 H{sub 2}O, and balance N{sub 2} in the temperature range of 343-538 C. Regenerations were conducted at temperatures in the range of 400-600 C with air-N{sub 2} mixtures. To prevent sulfation, catalyst additives were investigated that promote regeneration at lower temperatures. Characterization were performed for fresh, sulfided and regenerated sorbents.

  18. Zinc-oxide-based sorbents and processes for preparing and using same

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasael

    2010-03-23

    Zinc oxide-based sorbents, and processes for preparing and using them are provided. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  19. Zinc oxide-based sorbents and processes for preparing and using same

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2005-10-04

    Zinc oxide-based sorbents, and processes for preparing and using them are provided, wherein the sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents contain an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2 O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, containing a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  20. Microbial Enzyme Activity and Carbon Cycling in Grassland Soil Fractions

    NASA Astrophysics Data System (ADS)

    Allison, S. D.; Jastrow, J. D.

    2004-12-01

    Extracellular enzymes are necessary to degrade complex organic compounds present in soils. Using physical fractionation procedures, we tested whether old soil carbon is spatially isolated from degradative enzymes across a prairie restoration chronosequence in Illinois, USA. We found that carbon-degrading enzymes were abundant in all soil fractions, including macroaggregates, microaggregates, and the clay fraction, which contains carbon with a mean residence time of ~200 years. The activities of two cellulose-degrading enzymes and a chitin-degrading enzyme were 2-10 times greater in organic matter fractions than in bulk soil, consistent with the rapid turnover of these fractions. Polyphenol oxidase activity was 3 times greater in the clay fraction than in the bulk soil, despite very slow carbon turnover in this fraction. Changes in enzyme activity across the restoration chronosequence were small once adjusted for increases in soil carbon concentration, although polyphenol oxidase activity per unit carbon declined by 50% in native prairie versus cultivated soil. These results are consistent with a `two-pool' model of enzyme and carbon turnover in grassland soils. In light organic matter fractions, enzyme production and carbon turnover both occur rapidly. However, in mineral-dominated fractions, both enzymes and their carbon substrates are immobilized on mineral surfaces, leading to slow turnover. Soil carbon accumulation in the clay fraction and across the prairie restoration chronosequence probably reflects increasing physical isolation of enzymes and substrates on the molecular scale, rather than the micron to millimeter scale.

  1. A Magnesium-Activated Carbon Hybrid Capacitor

    SciTech Connect

    Yoo, HD; Shterenberg, I; Gofer, Y; Doe, RE; Fischer, CC; Ceder, G; Aurbach, D

    2013-12-11

    Prototype cells of hybrid capacitor were developed, comprising activated carbon (AC) cloth and magnesium (Mg) foil as the positive and negative electrodes, respectively. The electrolyte solution included ether solvent (TBF) and a magnesium organo-halo-aluminate complex 0.25 M Mg2Cl3+-Ph2AlCl2-. In this solution Mg can be deposited/dissolved reversibly for thousands of cycles with high reversibility (100% cycling efficiency). The main barrier for integrating porous AC electrodes with this electrolyte solution was the saturation of the pores with the large ions in the AC prior to reaching the potential limit. This is due to the existence of bulky Mg and Al based ionic complexes consisting Cl, alkyl or aryl (R), and THF ligands. This problem was resolved by adding 0.5 M of lithium chloride (LiCl), thus introducing sma