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Sample records for activated carbon production

  1. 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 inferred from their physical and chemical properties. The developed porosity of the activated carbon was a function of the oxygen content, porosity and H/C ratio of the parent unburned carbon feedstock. It was observed that extended activation times and high activation temperatures increased the porosity of the produced activated carbon at the expense of the solid yield. The development of activated carbon from unburned carbon in fly ash has been proven to be a success by this study in terms of the higher surface areas of the resultant activated carbons, which are comparable with commercial activated carbons. However, unburned carbon samples obtained from coal-fired power plants as by-product have high ash content, which is unwanted for the production of activated carbons. Therefore, the separation of unburned carbon from the fly ash is expected to be beneficial for the utilization of unburned carbon to produce activated carbons with low ash content.

  2. Reprocessing of used tires into activated carbon and other products

    SciTech Connect

    Teng, H.; Serio, M.A.; Wojtowicz, M.A.; Bassilakis, R.; Solomon, P.R.

    1995-09-01

    Landfilling used tires which are generated each year in the US is increasingly becoming an unacceptable solution. A better approach, from an environmental and economic standpoint, is to thermally reprocess the tires into valuable products such as activated carbon, other solid carbon forms (carbon black, graphite, and carbon fibers), and liquid fuels. In this study, high surface area activated carbons (> 800 m{sup 2}/g solid product) were produced in relatively high yields by pyrolysis of tires at up to 900 C, followed by activation in CO{sub 2} at the same temperature. The surface areas of these materials are comparable with those of commercial activated carbons. The efficiency of the activation process (gain in specific surface area/loss in mass) was greatest (up to 138 m{sup 2}/g original tire) when large pieces of tire material were used ({approximately} 170 mg). Oxygen pretreatment of tires was found to enhance both the yield and the surface area of the carbon product. High-pressure treatment of tires at low temperatures (< 400 C) is an alternative approach if the recovery of carbon black or fuel oils is the primary objective.

  3. JV Task 90 - Activated Carbon Production from North Dakota Lignite

    SciTech Connect

    Steven Benson; Charlene Crocker; Rokan Zaman; Mark Musich; Edwin Olson

    2008-03-31

    The Energy & Environmental Research Center (EERC) has pursued a research program for producing activated carbon from North Dakota lignite that can be competitive with commercial-grade activated carbon. As part of this effort, small-scale production of activated carbon was produced from Fort Union lignite. A conceptual design of a commercial activated carbon production plant was drawn, and a market assessment was performed to determine likely revenue streams for the produced carbon. Activated carbon was produced from lignite coal in both laboratory-scale fixed-bed reactors and in a small pilot-scale rotary kiln. The EERC was successfully able to upgrade the laboratory-scale activated carbon production system to a pilot-scale rotary kiln system. The activated carbon produced from North Dakota lignite was superior to commercial grade DARCO{reg_sign} FGD and Rheinbraun's HOK activated coke product with respect to iodine number. The iodine number of North Dakota lignite-derived activated carbon was between 600 and 800 mg I{sub 2}/g, whereas the iodine number of DARCO FGD was between 500 and 600 mg I{sub 2}/g, and the iodine number of Rheinbraun's HOK activated coke product was around 275 mg I{sub 2}/g. The EERC performed both bench-scale and pilot-scale mercury capture tests using the activated carbon made under various optimization process conditions. For comparison, the mercury capture capability of commercial DARCO FGD was also tested. The lab-scale apparatus is a thin fixed-bed mercury-screening system, which has been used by the EERC for many mercury capture screen tests. The pilot-scale systems included two combustion units, both equipped with an electrostatic precipitator (ESP). Activated carbons were also tested in a slipstream baghouse at a Texas power plant. The results indicated that the activated carbon produced from North Dakota lignite coal is capable of removing mercury from flue gas. The tests showed that activated carbon with the greatest iodine number was superior to commercial DARCO FGD for mercury capture. The results of the activated carbon market assessment indicate an existing market for water treatment and an emerging application for mercury control. That market will involve both existing and new coal-fired plants. It is expected that 20% of the existing coal-fired plants will implement activated carbon injection by 2015, representing about 200,000 tons of annual demand. The potential annual demand by new plants is even greater. In the mercury control market, two characteristics are going to dominate the customer's buying habit-performance and price. As continued demonstration testing of activated carbon injection at the various coal-fired power plants progresses, the importance of fuel type and plant configuration on the type of activated carbon best suited is being identified.

  4. Production and characterization of activated carbons from cereal grains

    SciTech Connect

    Venkatraman, A.; Walawender, W.P.; Fan, L.T.

    1996-12-31

    The term, activated carbon, is a generic name for a family of carbonaceous materials with well-developed porosities and consequently, large adsorptive capacities. Activated carbons are increasingly being consumed worldwide for environmental applications such as separation of volatiles from bulk gases and purification of water and waste-water streams. The global annual production is estimated to be around 300 million kilograms, with a rate of increase of 7% each year. Activated carbons can be prepared from a variety of raw materials. Approximately, 60% of the activated carbons generated in the United States is produced from coal; 20%, from coconut shells; and the remaining 20% from wood and other sources of biomass. The pore structure and properties of activated carbons are influenced by the nature of the starting material and the initial physical and chemical conditioning as well as the process conditions involved in its manufacture. The porous structures of charcoals and activated carbons obtained by the carbonization of kernels have been characterized.

  5. Production Scale-Up or Activated Carbons for Ultracapacitors

    SciTech Connect

    Dr. Steven D. Dietz

    2007-01-10

    Transportation use accounts for 67% of the petroleum consumption in the US. Electric and hybrid vehicles are promising technologies for decreasing our dependence on petroleum, and this is the objective of the FreedomCAR & Vehicle Technologies Program. Inexpensive and efficient energy storage devices are needed for electric and hybrid vehicle to be economically viable, and ultracapacitors are a leading energy storage technology being investigated by the FreedomCAR program. The most important parameter in determining the power and energy density of a carbon-based ultracapacitor is the amount of surface area accessible to the electrolyte, which is primarily determined by the pore size distribution. The major problems with current carbons are that their pore size distribution is not optimized for liquid electrolytes and the best carbons are very expensive. TDA Research, Inc. (TDA) has developed methods to prepare porous carbons with tunable pore size distributions from inexpensive carbohydrate based precursors. The use of low-cost feedstocks and processing steps greatly lowers the production costs. During this project with the assistance of Maxwell Technologies, we found that an impurity was limiting the performance of our carbon and the major impurity found was sulfur. A new carbon with low sulfur content was made and found that the performance of the carbon was greatly improved. We also scaled-up the process to pre-production levels and we are currently able to produce 0.25 tons/year of activated carbon. We could easily double this amount by purchasing a second rotary kiln. More importantly, we are working with MeadWestvaco on a Joint Development Agreement to scale-up the process to produce hundreds of tons of high quality, inexpensive carbon per year based on our processes.

  6. Production of charcoal and activated carbon at elevated pressure

    SciTech Connect

    Dai, Xiangfeng; Norberg, N.; Antal, M.J. Jr.

    1995-12-31

    With its wide range of properties, charcoal finds many commercial applications for domestic cooking, refining of metals (steel, copper, bronze, nickel, aluminum and electro-manganese), production of chemicals (carbon disulfide, calcium carbide, silicon carbide, sodium cyanide, carbon black, fireworks, gaseous chemicals, absorbents, soil conditioners and pharmaceuticals), as well as production of activated carbon and synthesis gas. In 1991, the world production of charcoal was 22.8 million cubic meters (3.8 million metric tons) as shown in Table 1. Brazil is the world`s largest charcoal producer --- 5.9 million cubic meters or one million metric tons was produced in 1991, most of which is used in steel and iron industry. African countries produced 45% of the world total amount of charcoal, where 86% of the wood-based energy is for domestic use, most of which is inefficiently used. Charcoal is produced commercially in kilns with a 25% to 30% yield by mass on a 7 to 12 day operating cycle. Until recently, the highest yield of good quality charcoal reported in the literature was 38%. In this paper, and ASME code rated experimental system is presented for producing charcoal and activated carbon from biomass.

  7. Production of activated carbon from a new precursor: Molasses

    NASA Astrophysics Data System (ADS)

    Legrouri, K.; Ezzine, M.; Ichcho, S.; Hannache, H.; Denoyel, R.; Pailler, R.; Naslain, R.

    2005-03-01

    Activated carbon has been prepared from molasses, a natural precursor of vegetable origin resulting from the sugar industry in Morocco. The preparation of the activated carbon from the molasses has been carried out by impregnation of the precursor with sulfuric acid, followed by carbonization. The adsorption capacity, the BET surface area, and the pore volume of the activated carbon were determined. The micropore volume was assessed by Dubinin- Radushkevich (DR) equation. The activated materials are mainly microporous and show the type I isotherm of the Brunauer classification for nitrogen adsorption. The activation in steam yielded a carbon that contains both micropores and supermicropores. Analysis of the nitrogen isotherm by BET and DR methods established that most of obtained carbons are highly microporous, with high surface areas (? 1200 m2/g) and very low mesoporosity.

  8. Production and characterization of activated carbons from cereal grains

    SciTech Connect

    Venkatraman, A.; Walawender, S.P.; Fan, L.T.

    1996-10-01

    The kernels of grain such as corn and hard red winter wheat were subjected to a two-stage pyrolytic process to generate relatively high yields of charcoals. The process involved carbonization of the kernels at low temperatures (250-325{degrees}C) followed by complete devolatilization of the resultant charcoals at around 750{degrees}C. The charcoals were subsequently activated physically with CO{sub 2} at 800{degrees}C to yield activated carbons. The total pore volumes and surface areas of the activated carbons were determined at various degree of activation by physisorption methods. The surface areas from the nitrogen BET method ranged from 500 to 1750 m{sup 2}/g, while the total pore volumes obtained from the volumes at saturation were in the interval from 0.3 to 0.7 cm{sup 3}/g. The fractal nature of the pore interfaces as well as the existence of different types of pores were investigated through small-angle x-ray scattering.

  9. Production of activated carbon from coconut shell char in a fluidized bed reactor

    SciTech Connect

    Sai, P.M.S.; Ahmed, J.; Krishnaiah, K.

    1997-09-01

    Activated carbon is produced from coconut shell char using steam or carbon dioxide as the reacting gas in a 100 mm diameter fluidized bed reactor. The effect of process parameters such as reaction time, fluidizing velocity, particle size, static bed height, temperature of activation, fluidizing medium, and solid raw material on activation is studied. The product is characterized by determination of iodine number and BET surface area. The product obtained in the fluidized bed reactor is much superior in quality to the activated carbons produced by conventional processes. Based on the experimental observations, the optimum values of process parameters are identified.

  10. 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. PMID:26856444

  11. Application of thermal analysis techniques in activated carbon production

    USGS Publications Warehouse

    Donnals, G.L.; DeBarr, J.A.; Rostam-Abadi, M.; Lizzio, A.A.; Brady, T.A.

    1996-01-01

    Thermal analysis techniques have been used at the ISGS as an aid in the development and characterization of carbon adsorbents. Promising adsorbents from fly ash, tires, and Illinois coals have been produced for various applications. Process conditions determined in the preparation of gram quantities of carbons were used as guides in the preparation of larger samples. TG techniques developed to characterize the carbon adsorbents included the measurement of the kinetics of SO2 adsorption, the performance of rapid proximate analyses, and the determination of equilibrium methane adsorption capacities. Thermal regeneration of carbons was assessed by TG to predict the life cycle of carbon adsorbents in different applications. TPD was used to determine the nature of surface functional groups and their effect on a carbon's adsorption properties.

  12. Production of activated carbons from pyrolysis of waste tires impregnated with potassium hydroxide.

    PubMed

    Teng, H; Lin, Y C; Hsu, L Y

    2000-11-01

    Activated carbons were produced from waste tires using a chemical activation method. The carbon production process consisted of potassium hydroxide (KOH) impregnation followed by pyrolysis in N2 at 600-900 degrees C for 0-2 hr. The activation method can produce carbons with a surface area (SA) and total pore volume as high as 470 m2/g and 0.57 cm3/g, respectively. The influence of different parameters during chemical activation, such as pyrolysis temperature, holding time, and KOH/tire ratio, on the carbon yield and the surface characteristics was explored, and the optimum preparation conditions were recommended. The pore volume of the resulting carbons generally increases with the extent of carbon gasified by KOH and its derivatives, whereas the SA increases with degree of gasification to reach a maximum value, and then decreases upon further gasification. PMID:11111338

  13. Production of activated carbons from waste tire--process design and economical analysis.

    PubMed

    Ko, Danny C K; Mui, Edward L K; Lau, Ken S T; McKay, Gordon

    2004-01-01

    The process design and economic analysis of process plants to produce activated carbons from waste tires and coal have been performed. The potential range of products from each process has been considered, namely for waste tire--pyro-gas, active carbon, carbon black and pyro-oil; for coal--pyro-gas and active carbons. Sensitivity analyses have been carried out on the main process factors; these are product price, production capacity, total production cost, capital investment and the tipping fee. Net present values for the two plants at various discount factors have been determined and the internal rates of return have been determined as 27.4% and 18.9% for the waste tire plant and the coal plant, respectively. PMID:15504665

  14. Activated carbon from pyrolysis of brewer's spent grain: Production and adsorption properties.

    PubMed

    Vanreppelen, Kenny; Vanderheyden, Sara; Kuppens, Tom; Schreurs, Sonja; Yperman, Jan; Carleer, Robert

    2014-06-20

    Brewer's spent grain is a low cost residue generated by the brewing industry. Its chemical composition (high nitrogen content 4.35 wt.%, fibres, etc.) makes it very useful for the production of added value in situ nitrogenised activated carbon. The composition of brewer's spent grain revealed high amounts of cellulose (20.8 wt.%), hemicellulose (48.78 wt.%) and lignin (11.3 wt.%). The fat, ethanol extractives and ash accounted for 8.17 wt.%, 4.7 wt.% and 3.2 wt.%, respectively. Different activated carbons were produced in a lab-scale pyrolysis/activation reactor by applying several heat and steam activation profiles on brewer's spent grain. Activated carbon yields from 16.1 to 23.6 wt.% with high N-contents (> 2 wt.%) were obtained. The efficiency of the prepared activated carbons for phenol adsorption was studied as a function of different parameters: pH, contact time and carbon dosage relative to two commercial activated carbons. The equilibrium isotherms were described by the non-linear Langmuir and Freundlich models, and the kinetic results were fitted using the pseudo-first-order model and the pseudo-second-order model. The feasibility of an activated carbon production facility (onsite and offsite) that processes brewer's spent grain for different input feeds is evaluated based on a techno-economic model for estimating the net present value. Even though the model assumptions start from a rather pessimistic scenario, encouraging results for a profitable production of activated carbon using brewer's spent grain are obtained. PMID:25012859

  15. Improved Bioethanol Production Using Activated Carbon-treated Acid Hydrolysate from Corn Hull in Pachysolen tannophilus

    PubMed Central

    Seo, Hyeon-Beom; Kim, Seungseop; Lee, Hyeon-Yong

    2009-01-01

    To optimally convert corn hull, a byproduct from corn processing, into bioethanol using Pachysolen tannophlius, we investigated the optimal conditions for hydrolysis and removal of toxic substances in the hydrolysate via activated carbon treatment as well as the effects of this detoxification process on the kinetic parameters of bioethanol production. Maximum monosaccharide concentrations were obtained in hydrolysates in which 20 g of corn hull was hydrolyzed in 4% (v/v) H2SO4. Activated carbon treatment removed 92.3% of phenolic compounds from the hydrolysate. When untreated hydrolysate was used, the monosaccharides were not completely consumed, even at 480 h of culture. When activated carbon-treated hydrolysate was used, the monosaccharides were mostly consumed at 192 h of culture. In particular, when activated carbon-treated hydrolysate was used, bioethanol productivity (P) and specific bioethanol production rate (Qp) were 2.4 times and 3.4 times greater, respectively, compared to untreated hydrolysate. This was due to sustained bioethanol production during the period of xylose/arabinose utilization, which occurred only when activated carbon-treated hydrolysate was used. PMID:23983522

  16. Renewable phenols production by catalytic microwave pyrolysis of Douglas fir sawdust pellets with activated carbon catalysts.

    PubMed

    Bu, Quan; Lei, Hanwu; Wang, Lu; Wei, Yi; Zhu, Lei; Liu, Yupeng; Liang, Jing; Tang, Juming

    2013-08-01

    The effects of different activated carbon (AC) catalysts based on various carbon sources on products yield and chemical compositions of upgraded pyrolysis oils were investigated using microwave pyrolysis of Douglas fir sawdust pellets. Results showed that high amounts of phenols were obtained (74.61% and 74.77% in the upgraded bio-oils by DARCO MRX (wood based) and DARCO 830 (lignite coal based) activated carbons, respectively). The catalysts recycling test of the selected catalysts indicated that the carbon catalysts can be reused for at least 3-4 times and produced high concentrations of phenol and phenolic compounds. The chemical reaction mechanism for phenolics production during microwave pyrolysis of biomass was analyzed. PMID:23765005

  17. Production of activated carbon and its catalytic application for oxidation of hydrogen sulphide

    NASA Astrophysics Data System (ADS)

    Azargohar, Ramin

    Hydrogen sulphide is an environmentally hazardous gas which is present in many gas streams associated with oil and gas industry. Oxidation of H 2S to sulphur in air produces no bulky or waste material and requires no further purification. Activated carbon is known as a catalyst for this reaction. In this research, a coal-based precursor (luscar char) and a biomass-based precursor (biochar) were used for production of activated carbons by two common methods of activation: physical and chemical activation in which steam and potassium hydroxide (KOH), respectively, were used. Experiments were designed by the statistical central composite design method. Two models were developed for the BET surface area and reaction yield of each activation process. These models showed the effects of operating conditions, such as activation temperature, mass ratio of activating agent to precursor, activation time, and nitrogen flowrate on the BET surface area and reaction yield for each activation method for each precursor. The optimum operating conditions were calculated using these models to produce activated carbons with relatively large BET surface area (> 500 m2/g) and high reaction yield (> 50 wt %). The BET surface area and reaction yield for activated carbons produced at optimum operating conditions showed maximum 7 and 7.4% difference, respectively, comparing to the values predicted by models. The activated carbons produced at optimum operating conditions were used as the base catalysts for the direct oxidation of 1 mol % hydrogen sulphide in nitrogen to sulphur at the temperature range of 160-205°C and pressure of 700 kPa. Originally activated carbons showed a good potential for oxidation of hydrogen sulphide by their selectivity for sulphur product and low amount of sulphur dioxide production. To improve the performance of steam-activated carbons, the catalysts were modified by acid-treatment followed by thermal desorption. This method increased the break-through times for coal-based and biomass-based catalysts to 115 and 141 minutes, respectively. The average amounts of sulphur dioxide produced during the reaction time were 0.14 and 0.03% (as % of hydrogen sulphide fed to the reactor) for modified activated carbons prepared from biochar and luscar char, respectively. The effects of porous structure, surface chemistry, and ash content on the performances of these activated carbon catalysts were investigated for the direct oxidation reaction of hydrogen sulphide. The acid-treatment followed by thermal desorption of activated carbons developed the porosity which produced more surface area for active sites and in addition, provided more space for sulphur product storage resulting in higher life time for catalyst. Boehm titration and temperature program desorption showed that the modification method increased basic character of carbon surface after thermal desorption in comparison to acid-treated sample. In addition, the effects of impregnating agents (potassium iodide and manganese nitrate) and two solvents for impregnation process were studied on the performance of the activated carbon catalysts for the direct oxidation of H2S to sulphur. Sulphur L-edge X-ray near edge structure (XANES) showed that the elemental sulphur was the dominant sulphur species in the product. The kinetic study for oxidation reaction of H2S over LusAC-O-D(650) was performed for temperature range of 160-190°C, oxygen to hydrogen sulphide molar ratio of 1-3, and H2S concentration of 6000-10000 ppm at 200 kPa. The values of activation energy were 26.6 and 29.3 kJ.gmol-1 for Eley-Rideal and Langmuir-Hinshelwood mechanisms, respectively.

  18. EFFECTS OF SODIUM AND CALCIUM IN LIGNITE ON THE PERFORMANCE OF ACTIVATED CARBON PRODUCTS

    SciTech Connect

    Edwin S. Olson; Kurt E. Eylands; Daniel J. Stepan

    2001-12-01

    Powdered activated carbon (PAC) has traditionally been used by the water treatment industry for the removal of compounds contributing to taste and odor problems. PAC also has the potential to remove naturally occurring organic matter (NOM) from raw waters prior to disinfection, thus controlling the formation of regulated disinfection by-products (DBPs). Many small water systems are currently using PAC for taste and odor control and have the potential to use PAC for controlling DBPs. The Energy & Environmental Research Center has been working on the development of a PAC product to remove NOM from surface water supplies to prevent the formation of carcinogenic DBPs during chlorination. During previous studies, the sodium and calcium content of the lignites showed a significant effect on the sorption capacity of the activated carbon product. As much as a 130% increase in the humic acid sorption capacity of a PAC produced from a high-sodium-content lignite was observed. During this study, activated carbons were prepared from three coals representing high-sodium, low-sodium--low-calcium, and high-calcium compositions in two steps, an initial char formation followed by mild activation with steam to avoid excessive burnout. This set of carbons was characterized with respect to physical and chemical properties. The BET (Brunauer-Emmett-Teller) nitrogen adsorption isotherms gave relatively low surface areas (ranging from 245 to 370 m{sup 2}/g). The lowest-BET area was obtained for the high-sodium carbon, which can be attributed to enlargement of micropores as a result of sodium-catalyzed gasification reaction of the carbon structure. This hypothesis is consistent with the scanning electron microscopy microprobe analyses, which show that in both the coal and the activated carbon from this coal, the sodium is distributed over both the carbon structure and the mineral particles. Thus it is initially associated with carboxylate groups on the coal and then as sodium oxide or other active form in close proximity to the carbon and is, therefore, readily available for catalysis of gasification. Humate adsorption isotherms for the high-sodium carbon gave superior results as defined by very high intercepts in modified Freundlich plots. Thus the high-sodium carbon will be considerably more effective in reducing the humate concentration for a given carbon dosage. Analysis of adsorption isotherms indicated the results were consistent with the hypothesis that only the larger pores are effective for binding the large humate molecules, and that the larger pores developed during activation of the high-sodium char give the appropriate macropore structure for humate binding. Toluene adsorption isotherms indicated that the high-calcium carbon and the low-calcium, low-sodium carbon were superior to the high-sodium carbon for small molecules in aqueous solution, but not as effective as a Calgon F-400 commercial activated carbon. This is consistent with the low-BET surface areas observed for the lignite-derived carbons, and thus there are a lower number of sites for binding the smaller toluene molecule in these carbons.

  19. PRODUCTION OF GRANULAR ACTIVATED CARBONS FROM PIG MANURE FOR METAL IONS ADSORPTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The current method of processing pig waste involves diluting it into large lagoons, which carries both environmental and human health risks. Alternatives to pig waste disposal are its reuse into value added products. This study produces activated carbons from swine manure and characterizes them in...

  20. Production of activated carbon from a new precursor molasses by activation with sulphuric acid.

    PubMed

    Legrouri, K; Khouya, E; Ezzine, M; Hannache, H; Denoyel, R; Pallier, R; Naslain, R

    2005-02-14

    Activated carbon has been prepared from molasses, a natural precursor of vegetable origin resulting from the sugar industry in Morocco. The preparation of the activated carbon from the molasses has been carried out by impregnation of the precursor with sulphuric acid, followed by carbonisation at varying conditions (temperature and gas coverage) in order to optimize preparation parameters. The influence of activation conditions was investigated by determination of adsorption capacity of methylene blue and iodine, the BET surface area, and the pore volume of the activated carbon were determined while the micropore volume was determined by the Dubinin-Radushkevich (DR) equation. The activated materials are mainly microporous and reveal the type I isotherm of the Brunauer classification for nitrogen adsorption. The activated carbons properties in this study were found for activation of the mixture (molasses/sulphuric acid) in steam at 750 degrees C. The samples obtained in this condition were highly microporous, with high surface area (> or =1200 m2/g) and the maximum adsorption capacity of methylene blue and iodine were 435 and 1430 mg/g, respectively. PMID:15721553

  1. Antifeedant activity of xanthohumol and supercritical carbon dioxide extract of spent hops against stored product pests.

    PubMed

    Jackowski, J; Hurej, M; Rj, E; Pop?o?ski, J; Ko?ny, L; Huszcza, E

    2015-08-01

    Xanthohumol, a prenylated flavonoid from hops, and a supercritical carbon dioxide extract of spent hops were studied for their antifeedant activity against stored product insect pests: Sitophilus granarius L., Tribolium confusum Duv. and Trogoderma granarium Everts. Xanthohumol exhibited medium deterrent activity against the adults of S. granarius L. and larvae of T. confusum Duv. The spent hops extract was more active than xanthohumol towards the adults of T. confusum Duv. The potential application of the crude spent hops extract as a feeding deterrent against the stored product pests is proposed. PMID:25851834

  2. 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).

  3. Can iron-making and steelmaking slag products be used to sequester CO2? Passive weathering and active carbonation experiments.

    NASA Astrophysics Data System (ADS)

    Worrall, Fred; Dobrzański, Andrew

    2015-04-01

    The high calcium content of iron and steel-making slags has been highlighted as providing a suitable feedstock material and medium with which to sequester CO2 into geologically stable carbonate phases. Optimisation of the natural carbonation process provides the potential for increasing the degree of carbonation above that possible via passive weathering. This study has assessed the baseline passive carbonation potential of several different slag products (graded steel slag aggregate, pellite, GBFS) within the climate of the northern UK. This baseline was then used as a comparison to the carbonation values achieved by the same products when actively reacted in a CO2-rich environment. The active carbonation phase of the project involved a factorial experimental study of materials reacted at 1MPa/10MPa CO2 pressure and 25˚C/125˚C. This study has shown: 1) That active carbonation of these products can successfully sequester additional CO2. 2) Carbonation potential in general is highly dependent upon grain size within material types, 3) There is a material-dependant cost-benefit issue when using different active carbonation conditions as well as the choice to use active vs. passive carbonation. The median sequestration potential of the slag products in this study is equivalent to the total emissions from 910 people from the UK; the CO2 emissions from 10000 tonnes of cement production; or 340000 tonnes of steel production.

  4. Utilization of date stones for production of activated carbon using phosphoric acid

    SciTech Connect

    Haimour, N.M. . E-mail: nomanhaimour@hotmail.com; Emeish, S. . E-mail: s_emiesh@yahoo.com

    2006-07-01

    Date stone wastes have been utilized for production of activated carbon by chemical activation with phosphoric acid using a fluidized-bed reactor. The effects of the activation time, activation temperature, impregnation ratio, and particle size on the yield and the adsorptive capacity towards iodine were studied. The yield and the quality of the activated carbon prepared by using H{sub 3}PO{sub 4} were compared with that prepared from date stones using the same equipment, and under similar conditions by using ZnCl{sub 2} as an oxidizing agent. The maximum value of the iodine number of the activated carbon produced using H{sub 3}PO{sub 4} in this work was about 495 under the following conditions: impregnation ratio 0.4, activation time 60 min, activation temperature 800 deg. C, particle size 0.60 mm. The iodine number for the produced activated carbon was higher when phosphoric acid was used, compared to that when zinc chloride was used as impregnation reagent; however, the yield obtained when H{sub 3}PO{sub 4} was used was lower than the yield when ZnCl{sub 2} was used. The iodine number increases significantly with increasing the activation temperature. By increasing the impregnation ratio at the same temperature, the iodine number decreased sharply and an oscillation is noticed for all the cases but it was clearer at 800 deg. C. The average variation of the iodine number for the whole range of particle size used in this work is {+-}10%.

  5. EFFECTS OF SODIUM AND CALCIUM IN LIGNITE ON THE PERFORMANCE OF ACTIVATED CARBON PRODUCTS

    SciTech Connect

    Edwin S. Olson; Kurt E. Eylands; Daniel J. Stepan

    2001-12-01

    New federal drinking water regulations have been promulgated to restrict the levels of disinfection by-products (DBPs) in finished public water supplies. DBPs are suspected carcinogens and are formed when organic material is partially oxidized by disinfectants commonly used in the water treatment industry. Additional federal mandates are expected in the near future that will also affect public water suppliers with respect to DBPs. These new federal drinking water regulations may require public water suppliers to adjust treatment practices or incorporate additional treatment operations into their existing treatment trains. Many options have been identified, including membrane processes, granular activated carbon, powered activated carbon (PAC), enhanced coagulation and/or softening, and alternative disinfectants (e.g., chlorine dioxide, ozone, and chloramines). Of the processes being considered, PAC appears to offer an attractive benefit-to-cost advantage for many water treatment plants, particularly small systems (those serving fewer than 10,000 customers). PAC has traditionally been used by the water treatment industry for the removal of compounds contributing to taste and odor problems. PAC also has the potential to remove naturally occurring organic matter (NOM) from raw waters prior to disinfection, thus controlling the formation of regulated DBPs. Many small water systems are currently using PAC for taste and odor control and have the potential to use PAC for controlling DBPs. Activated carbons can be produced from a variety of raw materials, including wood, peat, coconut husks, and numerous types of coal. The Energy & Environmental Research Center (EERC) has been working on the development of a PAC product to remove NOM from surface water supplies to prevent the formation of carcinogenic DBPs during chlorination. During that study, the sodium and calcium content of the lignites showed a significant effect on the sorption capacity of the activated carbon product. As much as a 130% increase in the humic acid sorption capacity of a PAC produced from a high-sodium-content lignite was observed. We hypothesize that the sodium and calcium content of the coal plays a significant role in the development of pore structures and pore-size distribution, ultimately producing activated carbon products that have greater sorption capacity for specific contaminants, depending on molecular size.

  6. Optimization of production conditions for activated carbons from Tamarind wood by zinc chloride using response surface methodology.

    PubMed

    Sahu, J N; Acharya, Jyotikusum; Meikap, B C

    2010-03-01

    The low-cost activated carbon was prepared from Tamarind wood an agricultural waste material, by chemical activation with zinc chloride. Activated carbon adsorption is an effective means for reducing organic chemicals, chlorine, heavy metals and unpleasant tastes and odours in effluent or colored substances from gas or liquid streams. Central composite design (CCD) was applied to study the influence of activation temperature, chemical ratio of zinc chloride to Tamarind wood and activation time on the chemical activation process of Tamarind wood. Two quadratic models were developed for yield of activated carbon and adsorption of malachite green oxalate using Design-Expert software. The models were used to calculate the optimum operating conditions for production of activated carbon providing a compromise between yield and adsorption of the process. The yield (45.26 wt.%) and adsorption (99.9%) of the activated carbon produced at these operating conditions showed an excellent agreement with the amounts predicted by the models. PMID:19913410

  7. The production of activated carbon from high-ash sub-bituminous and bituminous South African coals

    SciTech Connect

    Prinsloo, F.F.; Opperman, D.P.J.; Budeli, C.; Hauman, D.

    1999-07-01

    This paper describes a process for the production of activated carbon in a pilot rotary kiln. The first step comprises crushing and/or sieving and beneficiation of the different ROM coal precursors. The coal precursors used in this investigation are part of Sasol's resources and although they show high reactivity towards steam and CO{sub 2} they unfortunately contains high ash contents. Consequently it is necessary to beneficiate the ROM coal in a second step, to be a suitable feedstock for the production of activated carbon. The final step in the process entails devolatilization and activation of the beneficiated precursors in one continuous step in the kiln. The product characterization results demonstrate that the adsorption features of the activated carbons produced by Sasol compare favorably with that of commercial products.

  8. Production of activated carbon by K2CO3 activation treatment of cornstalk lignin and its performance in removing phenol and subsequent bioregeneration.

    PubMed

    Sun, Yong; Wei, Jian; Wang, Yun-Shan; Yang, Gang; Zhang, Jing-Ping

    2010-01-01

    Activated carbon was produced by fast precarbonization of cornstalk lignin in a fluidized bed followed by K2CO3 activation. The results showed that the product is essentially microporous carbon whose Brunauer-Emmett-Teller surface area and pore volume when the carbon was activated at 800 degrees C were 1410 m2/g and 0.77 mL/g, respectively. The potential usefulness of the resultant carbons for removal of phenol from water and their subsequent bioregeneration capabilities were also investigated. The kinetics study showed that all the carbons exhibited a fast adsorption rate and the carbon activated at 800 degrees C had the largest amount of phenol adsorbed due to its greater specific surface area and pore volume. The adsorption isotherms by applying the Langmuir method showed that the monolayer adsorption capacity of carbon activated at 800 degrees C could reach 110.9 mg/g. PMID:20232679

  9. H2 production with anaerobic sludge using activated-carbon supported packed-bed bioreactors.

    PubMed

    Lee, Kuo-Shing; Lo, Yung-Sheng; Lo, Yung-Chung; Lin, Ping-Jei; Chang, Jo-Shu

    2003-01-01

    Packed-bed bioreactors containing activated carbon as support carrier were used to produce H2 anaerobically from a sucrose-limiting medium while acclimated sewage sludge was used as the H2 producer. The effects of bed porosity (epsilon(b)) and substrate loading rate on H2 fermentation were examined using packed beds with epsilon(b) of 70-90% being operated at hydraulic retention times (HRT) of 0.5-4 h. Higher epsilon(b) and lower HRT favored H2 production. With 20 g COD l(-1) of sucrose in the feed, the optimal H2 production rate (7.4 l h(-1) l(-1)) was obtained when the bed with epsilon(b) = 90% was operated at HRT = 0.5 h. Flocculation of cells enhanced the retention of sludge for stable operations of the bioreactor at low HRTs. The gas products resulting from fermentative H2 production consisted of 30-40% H2 and 60-70% CO2. Butyric acid was the primary soluble product, followed by propionic acid and valeric acid. PMID:12882288

  10. Production and comparison of high surface area bamboo derived active carbons.

    PubMed

    Ip, A W M; Barford, J P; McKay, G

    2008-12-01

    High surface area activated carbons have been produced from the natural biomaterial bamboo, using phosphoric acid as the activating agent. The effects of phosphoric acid impregnation ratio, activation temperature, heating rate on the carbon surface area, porosity and mass yield are presented. Three of these bamboo derived active carbons, surface areas 1337, 1628 and 2123m(2)/g were assessed for their ability to adsorb Acid Red 18 dye from aqueous solution; these results were compared with three conventional adsorbents: activated carbon F400, bone char and peat. Isotherm data were analysed using Langmuir, Freundlich, Redlich-Peterson and Langmuir-Freundlich isotherms. Different isotherms provided the best fit correlations to the adsorption experimental data but the Langmuir-Freundlich equation provided the best overall correlation of data. The adsorption capacities of two of the selected bamboo derived carbons were much greater than the capacities of the other three adsorbents. PMID:18572403

  11. Rates of dissolved organic carbon (DOC) production and bacterial activity in the eastern North Atlantic Subtropical Gyre during summer

    NASA Astrophysics Data System (ADS)

    Teira, E.; Paz, M. J.; Quevedo, M.; Fuentes, M. V.; Niell, F. X.; Fernndez, E.

    2003-04-01

    Rates of particulate organic carbon production, dissolved organic carbon production (DOC) and bacterial production were measured at 8 stations located in the eastern North Atlantic Subtropical Gyre during August 1998. Euphotic-depth-integrated particulate organic carbon (POC) production rate was on average 27 mg C m-2 h-1. The corresponding averaged integrated DOC production rate was 5 mg C m-2 h-1, i.e., about 20 % of total primary production. No statistically significant relationship was found between the rates of DOC and POC production, suggesting that other processes besides phytoplankton exudation, such as cell lysis or protist grazing, could substantially contribute to the release of DOC. Euphotic-depth-integrated bacterial biomass and production were, on average, 214 mg C m-2 and 1.4 mg C m-2 h-1, respectively. The lack of correlation between the rates of DOC release and bacterial activity, and a bacterial carbon demand (BCD, calculated by using an estimated bacterial growth efficiency ranging from 11 to 18%) in excess of DOC production suggest the existence of additional organic carbon sources (both allochthonous and/or autochthonous reservoirs), apart from in situ phytoplankton-derived DOC production, for the maintenance of bacterial activity in this region during summer.

  12. A packed bed membrane reactor for production of biodiesel using activated carbon supported catalyst.

    PubMed

    Baroutian, Saeid; Aroua, Mohamed K; Raman, Abdul Aziz A; Sulaiman, Nik M N

    2011-01-01

    In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor. PMID:20888219

  13. GRANULAR ACTIVATED CARBON INSTALLATIONS

    EPA Science Inventory

    This paper presents a compilation and summary of design criteria, performance, and cost data from 22 operating municipal and industrial granular activated carbon (GAC) installations that treat water and wastewater or process food and beverage products. Guidance for using this inf...

  14. Resveratrol Induces Hepatic Mitochondrial Biogenesis Through the Sequential Activation of Nitric Oxide and Carbon Monoxide Production

    PubMed Central

    Kim, Seul-Ki; Joe, Yeonsoo; Zheng, Min; Kim, Hyo Jeong; Yu, Jae-Kyoung; Cho, Gyeong Jae; Chang, Ki Churl; Kim, Hyoung Kyu; Han, Jin; Ryter, Stefan W.

    2014-01-01

    Abstract Aims: Nitric oxide (NO) can induce mitochondrial biogenesis in cultured cells, through increased guanosine 3′,5′-monophosphate (cGMP), and activation of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α). We sought to determine the role of NO, heme oxygenase-1 (HO-1), and its reaction product (carbon monoxide [CO]) in the induction of mitochondrial biogenesis by the natural antioxidant resveratrol. Results: S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, induced mitochondrial biogenesis in HepG2 hepatoma cells, and in vivo, through stimulation of PGC-1α. NO-induced mitochondrial biogenesis required cGMP, and was mimicked by the cGMP analogue (8-bromoguanosine 3′,5′-cyclic monophosphate [8-Br-cGMP]). Activation of mitochondrial biogenesis by SNAP required HO-1, as it could be reversed by genetic interference of HO-1; and by treatment with the HO inhibitor tin-protoporphyrin-IX (SnPP) in vitro and in vivo. Cobalt protoporphyrin (CoPP)-IX, an HO-1 inducing agent, stimulated mitochondrial biogenesis in HepG2 cells, which could be reversed by the CO scavenger hemoglobin. Application of CO, using the CO-releasing molecule-3 (CORM-3), stimulated mitochondrial biogenesis in HepG2 cells, in a cGMP-dependent manner. Both CoPP and CORM-3-induced mitochondrial biogenesis required NF-E2-related factor-2 (Nrf2) activation and phosphorylation of Akt. The natural antioxidant resveratrol induced mitochondrial biogenesis in HepG2 cells, in a manner dependent on NO biosynthesis, cGMP synthesis, Nrf2-dependent HO-1 activation, and endogenous CO production. Furthermore, resveratrol preserved mitochondrial biogenesis during lipopolysaccharides-induced hepatic inflammation in vivo. Innovation and Conclusions: The complex interplay between endogenous NO and CO production may underlie the mechanism by which natural antioxidants induce mitochondrial biogenesis. Strategies aimed at improving mitochondrial biogenesis may be used as therapeutics for the treatment of diseases involving mitochondrial dysfunction. Antioxid. Redox Signal. 20, 2589–2605. PMID:24041027

  15. Microbial activity and dissolved organic carbon production in drained and rewetted blanket peat

    NASA Astrophysics Data System (ADS)

    Wallage, Z. E.; Holden, J.; Jones, T.; McDonald, A. T.

    2009-04-01

    Heightened levels of degradation in response to environmental change have resulted in an increased loss of dissolved organic carbon (DOC) in the drainage waters of many peatland catchments across Europe and North America. One significant threat to peatland sustainability has been the installation of artificial drainage ditches, and although recent restoration schemes have pursued drain blocking as a possible strategy for reducing degradation and fluvial carbon losses, little is known about how such processes influence the intimate biological systems operating within these soils. This paper investigates how disturbance, in the form of drainage and drain blocking, influences the rate of microbial activity within a peat soil, and the subsequent impact this has on DOC production potential. Peat samples were extracted from three treatment sites (intact peat, drained peat and drain-blocked peat) in an upland blanket peat catchment in the UK. Microbial activity was measured via laboratory experimentation that incorporated the use of an INT-Formazan dehydrogenase enzyme assay to assess the level of electron transport system (ETS) activity occurring within each treatment. Drainage significantly lowered the height of the water table relative to the intact peat, whilst drain blocking successfully rewetted the peat, having raised the height of the water table relative to the drained site. Mean microbial activity rates at the drained site were found to be 33 % greater than the undisturbed intact peat and almost double that of the restored, drain-blocked site. These results correspond well with previously published data observing significantly greater DOC concentrations in the pore waters of the drained site and significantly lower concentrations at the blocked site, relative to the intact peat. Data from the drain-blocked treatment also provides evidence contrary to the commonly quoted hypothesis that an enzyme-latch reaction may be sustained in drained peat, even once it has been rewetted following water table restoration. Data is also presented that demonstrates how earlier research using INT-Formazan to assess microbial activity in peat, which has not incorporated correction for the spectrophotometric interference incurred from coloured DOC compounds, should be treated with caution.

  16. Production of energy and activated carbon from agri-residue: sunflower seed example.

    PubMed

    Donaldson, Adam A; Kadakia, Parag; Gupta, Murlidhar; Zhang, Zisheng

    2012-09-01

    In this work, a biomass processing facility is designed and simulated for the annual conversion of 77 ktons of sunflower residue into electricity and activated carbon. The residue is initially pyrolized to produce low hydrocarbon gases (35 wt%), bio-oils (30 wt%), and char (35 wt%). The gases and bio-oils are separated and combusted to generate high pressure steam, electricity, and steam for conversion of char into activated carbon. Assuming 35% of the char's mass is lost during activation, the proposed process produces 15.6 ktons activated carbon and 5.5 ktons ash annually, while generating 10.2 MW of electricity. Economic analysis of the proposed facility yielded capital costs of $31.64 million, annual operating costs of $31.58 million, and a yearly gross revenue of $38.9 million. A discounted payback period of 6.1 years was determined for the current design, extending to 10 years if the facility were operated at 75% capacity. While the proposed process appears to be economically viable, profitability is highly sensitive to the selling price of electricity and activated carbon, highlighting the need for additional research into the pyrolysis reactor design, char/ash separation techniques, and the quality of activated carbon obtained using char from sunflower residue pyrolysis. PMID:21938425

  17. PROCESS DESCRIPTION AND PRODUCT COST TO MANUFACTURE SUGARCANE BAGASSE-BASED GRANULAR ACTIVATED CARBON

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Process flow diagrams and manufacturing costs were developed to convert sugarcane bagasse to granular activated carbon. Unit operations in the conversion process consisted of milling, pelletization, pyrolysis/activation, washing with acid and water, and drying/screening/collecting of the final prod...

  18. Comparing a silver-impregnated activated carbon with an unmodified activated carbon for disinfection by-product minimisation and precursor removal.

    PubMed

    Watson, Kalinda; Farr, Maria Jos; Knight, Nicole

    2016-01-15

    During disinfection, bromide, iodide and natural organic matter (NOM) in source waters can lead to the formation of brominated and/or iodinated disinfection by-products (DBPs), which are often more toxic than their chlorinated analogues. The objective of this study was to compare the efficiency of a silver-impregnated activated carbon (SIAC) with the equivalent unimpregnated granular activated carbon (GAC) for the removal of bromide, iodide and NOM from a matrix of synthetic waters with variable NOM, halide, and alkalinity concentrations, and to investigate the impact on DBP formation. An enhanced coagulation (EC) pre-treatment was employed prior to sample exposure to either carbon adsorbent. Excellent halide removals were observed by the SIAC treatment across the sample matrix, with iodide concentrations consistently reduced to below the method reporting limit (<2 ?g/L) from as high as 25 ?g/L, and 954% removal of bromide achieved. Bromide removal by unimpregnated GAC was poor, however iodide removal was comparable to that achieved by SIAC. The combination of EC with SIAC treatment removed 778% of the dissolved organic carbon (DOC) present, across the sample matrix, which was similar to removals by EC/GAC (6714%). Combined EC/SIAC treatment reduced both total trihalomethanes (tTHMs) and total dihaloacetonitriles (tDHANs) formation by 973%, while also achieving a greater than 74% removal of two chloropropanones and a 928% decrease in chloral hydrate (CH), compared to untreated samples, regardless of the sample's starting water quality (bromide, alkalinity and NOM concentration). Combined EC/GAC treatment led to similar DBP removals to EC/SIAC for the fully chlorinated DBPs, however, brominated DBPs were less efficiently removed, or experienced concentration increases. PMID:26546763

  19. Enrichment of specific electro-active microorganisms and enhancement of methane production by adding granular activated carbon in anaerobic reactors.

    PubMed

    Lee, Jung-Yeol; Lee, Sang-Hoon; Park, Hee-Deung

    2016-04-01

    Direct interspecies electron transfer (DIET) via conductive materials can provide significant benefits to anaerobic methane formation in terms of production amount and rate. Although granular activated carbon (GAC) demonstrated its applicability in facilitating DIET in methanogenesis, DIET in continuous flow anaerobic reactors has not been verified. Here, evidences of DIET via GAC were explored. The reactor supplemented with GAC showed 1.8-fold higher methane production rate than that without GAC (35.7 versus 20.1±7.1mL-CH4/d). Around 34% of methane formation was attributed to the biomass attached to GAC. Pyrosequencing of 16S rRNA gene demonstrated the enrichment of exoelectrogens (e.g. Geobacter) and hydrogenotrophic methanogens (e.g. Methanospirillum and Methanolinea) from the biomass attached to GAC. Furthermore, anodic and cathodic currents generation was observed in an electrochemical cell containing GAC biomass. Taken together, GAC supplementation created an environment for enriching the microorganisms involved in DIET, which increased the methane production rate. PMID:26836607

  20. Production, characterization and application of activated carbon from brewer's spent grain lignin.

    PubMed

    Mussatto, Solange I; Fernandes, Marcela; Rocha, George J M; Orfo, Jos J M; Teixeira, Jos A; Roberto, Ins C

    2010-04-01

    Different types of activated carbon were prepared by chemical activation of brewer's spent grain (BSG) lignin using H(3)PO(4) at various acid/lignin ratios (1, 2, or 3g/g) and carbonization temperatures (300, 450, or 600 degrees C), according to a 2(2) full-factorial design. The resulting materials were characterized with regard to their surface area, pore volume, and pore size distribution, and used for detoxification of BSG hemicellulosic hydrolysate (a mixture of sugars, phenolic compounds, metallic ions, among other compounds). BSG carbons presented BET surface areas between 33 and 692 m(2)/g, and micro- and mesopores with volumes between 0.058 and 0.453 cm(3)/g. The carbons showed high capacity for adsorption of metallic ions, mainly nickel, iron, chromium, and silicon. The concentration of phenolic compounds and color were also reduced by these sorbents. These results suggest that activated carbons with characteristics similar to those commercially found and high adsorption capacity can be produced from BSG lignin. PMID:20004569

  1. ON-SITE PRODUCTION OF ACTIVATED CARBON FROM KRAFT BLACK LIQUOR

    EPA Science Inventory

    A pilot plant was designed and constructed to produce char via the St. Regis hydropyrolysis kraft chemical recovery process and to produce activated carbon from the char. This report includes discussion of laboratory and prepilot work, the pilot plant, and presents operating resu...

  2. ACTIVATED CARBON FROM BROILER LITTER: PROCESS DESCRIPTION AND COST OF PRODUCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal manure continues to represent a significantly large and problematic portion of the U.S. agricultural waste generated yearly. Granular activated carbons made from pelletized poultry litter have been shown to adsorb various positively charged metal ions from laboratory prepared solutions. Bas...

  3. Production of activated carbon by waste tire thermochemical degradation with CO2.

    PubMed

    Betancur, Mariluz; Martnez, Juan Daniel; Murillo, Ramn

    2009-09-15

    The thermochemical degradation of waste tires in a CO(2) atmosphere without previous treatment of devolatilization (pyrolysis) in order to obtain activated carbons with good textural properties such as surface area and porosity was studied. The operating variables studied were CO(2) flow rate (50 and 150 mL/min), temperature (800 and 900 degrees C) and reaction time (1, 1.5, 2, 2.5 and 3h). Results show a considerable effect of the temperature and the reaction time in the porosity development. Kinetic measurements showed that the reactions involved in the thermochemical degradation of waste tire with CO(2), are similar to those developed in the pyrolysis process carried out under N(2) atmosphere and temperatures below 760 degrees C, for particles sizes of 500 microm and heating rate of 5 degrees C/min. For temperatures higher than 760 degrees C the CO(2) starts to oxidize the remaining carbon black. Activated carbon with a 414-m(2)/g surface area at 900 degrees C of temperature, 150 mL/min of CO(2) volumetric flow and 180 min of reaction time was obtained. In this work it is considering the no reactivity of CO(2) for devolatilization of the tires (up to 760 degrees C), and also the partial oxidation of residual char at high temperature for activation (>760 degrees C). It is confirmed that there are two consecutive stages (devolatilization and activation) developed from the same process. PMID:19398156

  4. CHARACTERIZATION OF CARBON FIBER EMISSIONS FROM CURRENT AND PROJECTED ACTIVITIES FOR THE MANUFACTURE AND DISPOSAL OF CARBON FIBER PRODUCTS

    EPA Science Inventory

    Composite materials formed by impregnating a carbon or graphite fiber mat with plastic binders are being used increasingly in military, aerospace, sports and automotive applications. Carbon fibers are formed primarily from synthetic fibers carbonized in the absence of oxygen. Pos...

  5. 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...

  6. 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. PMID:25758836

  7. Removal of cadmium(II) from wastewater using activated carbon prepared from Agro Industrial by-products.

    PubMed

    Hema, M; Srinivasan, K

    2011-10-01

    Removal of cadmium from wastewater using activated carbons prepared from Cocos nucifera (coconut) and Azadirachta indica (neem) oilcakes-an agricultural solid by-product was investigated. Batch experiments were performed to evaluate the effect of pH, agitation time, initial metal ion concentration and adsorbent dose on the cadmium sorption in coconut oil cake activated carbon (COCAC) and neem oil cake activated carbon (NOCAC). The experiments demonstrated that the adsorption process corresponds to the pseudo-second-order-kinetic model and the equilibrium adsorption data fit well with Temkin isotherm model. The adsorption capacity 'b' calculated from the Langmuir isotherm was 188.68 mg/g for COCAC and 23.7 mg/g for NOCAC. The percent removal of Cd(II) in COCAC increased in pH from 2 to 5, and remained constant up to pH 8, increasing the percent removal with increasing pH for NOCAC. Desorption studies were performed with 0.1M hydrochloric acid. It was found that quantitative recovery of the metal ion is possible. It was also observed that the mechanism of adsorption seems to be ion exchange. Reuse of both carbons were carried out for five cycles at optimum conditions. Adsorption efficiency of carbons was reduced from 99 to 89% in the case of COCAC and 97 to 86% for NOCAC. PMID:23505814

  8. Electrochemical battery including a product of activated carbon fiber as an electrode

    SciTech Connect

    Nogami, T.; Nawa, M.

    1985-04-09

    Disclosed herein is an electrochemical battery having electrodes immersed in an organic solvent electrolyte solution so that the electromotive force is generated by doping to and/or undoping from said electrodes. One electrode is made of metal which is electrochemically equilibrated with cations in the electrolyte, and the other electrode is made of carbon molded product having a specific surface area of 100 to 2,500 m/sup 2//g. The electrodes according to this invention are capable of accepting a large quantity of doping, light in weight and easy to handle.

  9. Premium carbon products from coal

    SciTech Connect

    Rusinko, F. Jr.; Morrison, J.L.

    2000-07-01

    The face of the US coal industry and its markets are changing. Environmental concerns over global warming and plant emissions are two factors that will continue to gain national attention and consequently will challenge the use of coal in the US within its traditional markets. The decline of coke production in the US has lead to high quality metallurgical-grade coal being used to generate electricity. One could argue this is a waste of a limited valuable resource. The debate over global warming and the generation of greenhouse gases, particularly CO{sub 2}, will undoubtedly negatively impact the use of coal in newly constructed power plants. What is the future of the US coal industry and the industries that benefit from coal? This paper will review the use of coal and coal-derived materials in new, non-fuel markets. It will review a new industrial consortium that has recently been formed to stimulate the use of coal in value-added carbon markets. One of the questions the reader should ask when reading this paper is: Is coal more valuable for its carbon content or its BTU content? Carbon materials such as carbon fibers, carbon-carbon composites, specialty and mechanical graphite, activated carbon, carbon black, and carbon foams may provide new markets for the coal industry. These markets are expanding and some of these markets are in their infancy. These new material applications offer an exciting, but little recognized, opportunity for the expanded use of coal.

  10. Detoxification of Eucheuma spinosum Hydrolysates with Activated Carbon for Ethanol Production by the Salt-Tolerant Yeast Candida tropicalis.

    PubMed

    Ra, Chae Hun; Jung, Jang Hyun; Sunwoo, In Young; Kang, Chang Han; Jeong, Gwi-Taek; Kim, Sung-Koo

    2015-06-01

    The objective of this study was to optimize the slurry contents and salt concentrations for ethanol production from hydrolysates of the seaweed Eucheuma spinosum. A monosaccharide concentration of 44.2 g/l as 49.6% conversion of total carbohydrate of 89.1 g/l was obtained from 120 g dw/l seaweed slurry. Monosaccharides from E. spinosum slurry were obtained by thermal acid hydrolysis and enzymatic hydrolysis. Addition of activated carbon at 2.5% (w/v) and the adsorption time of 2 min were used in subsequent adsorption treatments to prevent the inhibitory effect of HMF. The adsorption surface area of the activated carbon powder was 1,400-1,600 m(2)/g and showed selectivity to 5-hydroxymethyl furfural (HMF) from monosaccharides. Candida tropicalis KCTC 7212 was cultured in yeast extract, peptone, glucose, and high-salt medium, and exposed to 80, 90, 100, and 110 practical salinity unit (psu) salt concentrations in the lysates. The 100 psu salt concentration showed maximum cell growth and ethanol production. The ethanol fermentations with activated carbon treatment and use of C. tropicalis acclimated to a high salt concentration of 100 psu produced 17.9 g/l of ethanol with a yield (YEtOH) of 0.40 from E. spinosum seaweed. PMID:25649983

  11. Simultaneous activation/sulfurization method for production of sulfurized activated carbons: characterization and Hg(II) adsorption capacity.

    PubMed

    Shamsijazeyi, Hadi; Kaghazchi, Tahereh

    2014-01-01

    As an inexpensive method for modification of activated carbons (ACs), sulfurization has attracted significant attention. However, the resulting sulfurized activated carbons (SACs) often are less porous than the original ACs. In this work, we propose a new method for concurrent sulfurization/activation that can lead to preparation of SACs with more porosity than the corresponding non-sulfurized ACs. By using scanning electron microscopy, nitrogen adsorption/desorption, and iodine number experiments, the porous structure of the SACs has been compared with that of non-sulfurized ACs. The specific surface areas of SACs are higher than the corresponding ACs, regardless of the type of activation agents used. For instance, the specific surface area of SAC and AC activated with phosphoric acid is 1,637 and 1,338 m(2)/g, respectively. Additionally, sulfur contents and surface charges (pHpzc) of the SACs and non-sulfurized ACs are compared. In fact, the SACs have higher sulfur contents and more acidic surfaces. Furthermore, the Hg(II) adsorption capacity of SACs has been compared with the corresponding non-sulfurized ACs. The Hg(II) adsorption isotherms on a selected SAC is measured at different pH values and temperatures. Hg(II) adsorptions as high as 293 mg/g are observed by using SACs prepared by the method proposed in this study. PMID:24552726

  12. Carbon Black Nanoparticles Promote Endothelial Activation and Lipid Accumulation in Macrophages Independently of Intracellular ROS Production

    PubMed Central

    Cao, Yi; Roursgaard, Martin; Danielsen, Pernille Hgh; Mller, Peter; Loft, Steffen

    2014-01-01

    Exposure to nanoparticles (NPs) may cause vascular effects including endothelial dysfunction and foam cell formation, with oxidative stress and inflammation as supposed central mechanisms. We investigated oxidative stress, endothelial dysfunction and lipid accumulation caused by nano-sized carbon black (CB) exposure in cultured human umbilical vein endothelial cells (HUVECs), THP-1 (monocytes) and THP-1 derived macrophages (THP-1a). The proliferation of HUVECs or co-cultures of HUVECs and THP-1 cells were unaffected by CB exposure, whereas there was increased cytotoxicity, assessed by the LDH and WST-1 assays, especially in THP-1 and THP-1a cells. The CB exposure decreased the glutathione (GSH) content in THP-1 and THP-1a cells, whereas GSH was increased in HUVECs. The reactive oxygen species (ROS) production was increased in all cell types after CB exposure. A reduction of the intracellular GSH concentration by buthionine sulfoximine (BSO) pre-treatment further increased the CB-induced ROS production in THP-1 cells and HUVECs. The expression of adhesion molecules ICAM-1 and VCAM-1, but not adhesion of THP-1 to HUVECs or culture dishes, was elevated by CB exposure, whereas these effects were unaffected by BSO pre-treatment. qRT-PCR showed increased VCAM1 expression, but no change in GCLM and HMOX1 expression in CB-exposed HUVECs. Pre-exposure to CB induced lipid accumulation in THP-1a cells, which was not affected by the presence of the antioxidant N-acetylcysteine. In addition, the concentrations of CB to induce lipid accumulation were lower than the concentrations to promote intracellular ROS production in THP-1a cells. In conclusion, exposure to nano-sized CB induced endothelial dysfunction and foam cell formation, which was not dependent on intracellular ROS production. PMID:25184212

  13. Activated carbon and biochar from agricultural by-products in the adorption of Cd, Pb and Zn under laboratory conditions

    NASA Astrophysics Data System (ADS)

    Coscione, Aline; Zini, Barbara

    2015-04-01

    The immobilization of inorganic contaminants by using biochar in soils has played an increasingly important role and it is seen as an attractive alternative for the remediation of heavy metals. Although, the production of activated carbon (CA) from agricultural by-products has received special attention, the activation of the the organic source has been studied in order to increase its porposity, surface area and chemical polarity, resulting in higher adsorption of metals. Therefore, this study aimed to evaluate the effectiveness of BC and CA samples, obtained from a eucalyptus husks and cane sugar bagasse after activation with 20% phosphoric acid and pyrolyzed at 450oC in the retention of Zn, Cd and Pb using contaminated individual solutions. The experiment was performed using samples of activated carbon of eucalyptus husk (CCA), eucalyptus husk biochar (BC), activated carbon of sugar cane bagasse (CBA) and sugar cane bagasse biochar (BB), treated with Zn, Cd (range of tested solution from 0.1 up to 12 mmol L-1) and Pb (from 0.1 up 50 mmol L-1) and the adjustemento of Langmuir adsorption isotherms. Samples obtained from bagasse presented higher adsoprtion of the metals tested then eucalyptus. Also the activation process had not the expected effect on either eucalyptus and bagasse samples The maxmum adsorption capacyty of samples were as follws, in mmol g-1: for Cd - 0.36 for BC; 0.32 for CCA; 0.40 for BB; 0.31 for CBA. For Zn- 0.14 for BC; no adsorbed by CCA; 0.35 5 for BB; 0.06 for CBA. For Pb - 1.24 for BC; 0.40 for CCA; 0,45 for BB; 0,03 for CBA. However, it was also observed that due to the activation with phosphoric acid, the pH of the activated carbon (CCA and CBA) were 2.4 and 2.5 in comparison with the biochars not activated (BC and BB) 9.7 and 7.0 respectively. Thus, it is yet not possible to state if the calculate capacity is due exclusively to the complexation of chemical groups in the surface of samples or to which extent there is a contribution of precipitation caused by the basic pH (non-activated) biochar samples, as shown for Zn and Pb.

  14. Production of granular activated carbon from food-processing wastes (walnut shells and jujube seeds) and its adsorptive properties.

    PubMed

    Bae, Wookeun; Kim, Jongho; Chung, Jinwook

    2014-08-01

    Commercial activated carbon is a highly effective absorbent that can be used to remove micropollutants from water. As a result, the demand for activated carbon is increasing. In this study, we investigated the optimum manufacturing conditions for producing activated carbon from ligneous wastes generated from food processing. Jujube seeds and walnut shells were selected as raw materials. Carbonization and steam activation were performed in a fixed-bed laboratory electric furnace. To obtain the highest iodine number, the optimum conditions for producing activated carbon from jujube seeds and walnut shells were 2 hr and 1.5 hr (carbonization at 700 degrees C) followed by 1 hr and 0.5 hr (activation at 1000 degrees C), respectively. The surface area and iodine number of activated carbon made from jujube seeds and walnut shells were 1,477 and 1,184 m2/g and 1,450 and 1,200 mg/g, respectively. A pore-distribution analysis revealed that most pores had a pore diameter within or around 30-40 angstroms, and adsorption capacity for surfactants was about 2 times larger than the commercial activated carbon, indicating that waste-based activated carbon can be used as alternative. Implications: Wastes discharged from agricultural and food industries results in a serious environmental problem. A method is proposed to convert food-processing wastes such as jujube seeds and walnut shells into high-grade granular activated carbon. Especially, the performance of jujube seeds as activated carbon is worthy of close attention. There is little research about the application ofjujube seeds. Also, when compared to two commercial carbons (Samchully and Calgon samples), the results show that it is possible to produce high-quality carbon, particularly from jujube seed, using a one-stage, 1,000 degrees C, steam pyrolysis. The preparation of activated carbon from food-processing wastes could increase economic return and reduce pollution. PMID:25185390

  15. 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.

  16. Bacterial Standing Stock, Activity, and Carbon Production during Formation and Growth of Sea Ice in the Weddell Sea, Antarctica †

    PubMed Central

    Grossmann, Sönnke; Dieckmann, Gerhard S.

    1994-01-01

    Bacterial response to formation and growth of sea ice was investigated during autumn in the northeastern Weddell Sea. Changes in standing stock, activity, and carbon production of bacteria were determined in successive stages of ice development. During initial ice formation, concentrations of bacterial cells, in the order of 1 × 108 to 3 × 108 liter-1, were not enhanced within the ice matrix. This suggests that physical enrichment of bacteria by ice crystals is not effective. Due to low concentrations of phytoplankton in the water column during freezing, incorporation of bacteria into newly formed ice via attachment to algal cells or aggregates was not recorded in this study. As soon as the ice had formed, the general metabolic activity of bacterial populations was strongly suppressed. Furthermore, the ratio of [3H]leucine incorporation into proteins to [3H]thymidine incorporation into DNA changed during ice growth. In thick pack ice, bacterial activity recovered and growth rates up to 0.6 day-1 indicated actively dividing populations. However, biomass-specific utilization of organic compounds remained lower than in open water. Bacterial concentrations of up to 2.8 × 109 cells liter-1 along with considerably enlarged cell volumes accumulated within thick pack ice, suggesting reduced mortality rates of bacteria within the small brine pores. In the course of ice development, bacterial carbon production increased from about 0.01 to 0.4 μg of C liter-1 h-1. In thick ice, bacterial secondary production exceeded primary production of microalgae. PMID:16349347

  17. Cloud condensation nucleation activities of calcium carbonate and its atmospheric ageing products.

    PubMed

    Tang, M J; Whitehead, J; Davidson, N M; Pope, F D; Alfarra, M R; McFiggans, G; Kalberer, M

    2015-12-28

    Aerosol particles can serve as cloud condensation nuclei (CCN) to form cloud droplets, and its composition is a main factor governing whether an aerosol particle is an effective CCN. Pure mineral dust particles are poor CCN; however, changes in chemical composition of mineral dust aerosol particles, due to heterogeneous reactions with reactive trace gases in the troposphere, can modify their CCN properties. In this study we investigated the CCN activities of CaCO3 (as a surrogate for mineral dust) and its six atmospheric ageing products: Ca(NO3)2, CaCl2, CaSO4, Ca(CH3SO3)2, Ca(HCOO)2, and Ca(CH3COO)2. CaCO3 has a very low CCN activity with a hygroscopicity parameter (?) of 0.001-0.003. The CCN activities of its potential atmospheric ageing products are significantly higher. For example, we determined that Ca(NO3)2, CaCl2 and Ca(HCOO)2 have ? values of ?0.50, similar to that of (NH4)2SO4. Ca(CH3COO)2 has slightly lower CCN activity with a ? value of ?0.40, and the ? value of CaSO4 is around 0.02. We further show that exposure of CaCO3 particles to N2O5 at 0% relative humidity (RH) significantly enhances their CCN activity, with ? values increasing to around 0.02-0.04. Within the experimental uncertainties, it appears that the variation in exposure to N2O5 from ?550 to 15?000 ppbv s does not change the CCN activities of aged CaCO3 particles. This observation indicates that the CaCO3 surface may be already saturated at the shortest exposure. We also discussed the atmospheric implications of our study, and suggested that the rate of change in CCN activities of mineral dust particles in the troposphere is important to determine their roles in cloud formation. PMID:26578034

  18. GRANULAR ACTIVATED CARBONS FROM AGRICULTURAL BY-PRODUCTS: POTENTIAL APPLICATIONS IN DRINKING WATER AND MUNICIPAL WASTEWATER TREATMENTS.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activated carbons are used routinely in the drinking water and wastewater treatment industries to remove principally organic contaminants. While coconut shell-based carbons are used in these applications, nutshell-based carbons from tree nuts originating from domestic or U.S. sources have not been ...

  19. Enhanced visible light photocatalytic H2 production activity of g-C3N4 via carbon fiber

    NASA Astrophysics Data System (ADS)

    Zhang, Jingtao; Huang, Feng

    2015-12-01

    H2 production from photocatalytic water splitting is an alternative way to develop reproducible energy. As one of the promising visible-light photocatalysts, graphitic carbon nitride (g-C3N4) endures fast recombination of photoinduced charges, which hinders its wide application for water splitting. To this end, novel carbon fiber (CF) and g-C3N4 composite photocatalysts were prepared through a facile two-step approach involving electrospinning and a subsequent calcination process. The incorporation of CF forms intimate interaction with g-C3N4, significantly enhancing the photocatalytic hydrogen production rate of the latter under visible light irradiation (λ ≥ 420 nm), reaching a maximal value of 1080 μmol h-1 g-1 which is about 4.6 times higher than that of pure g-C3N4. The improved photocatalytic activity in the CF/g-C3N4 composites are mainly attributed to the synergic effects of improved separation of electron-hole pairs through efficient electron transfer, increased specific surface area and pore volume, and enhanced visible light absorption. Moreover, a possible photocatalytic mechanism is proposed and verified by photoluminescene, photocurrent and electrochemical impedance spectroscopy. This study contributes to the further promising application of g-C3N4 for H2 production.

  20. Retention efficiency of Cd, Pb and Zn from agricultural by-products activated carbon and biochar under laboratory conditions

    NASA Astrophysics Data System (ADS)

    Coscione, Aline; Ramos, Barbara

    2015-04-01

    The immobilization of inorganic contaminants by using biochar in soils has played an increasingly important role and it is seen as an attractive alternative for the remediation of heavy metals. Although, the production of activated carbon (CA) from agricultural by-products has received special attention, the activation of the the organic source has been studied in order to increase its porposity, surface area and chemical polarity, resulting in higher adsorption of metals. Therefore, this study aimed to evaluate the effectiveness of BC and CA samples, obtained from a eucalyptus husks and cane sugar bagasse after activation with 20% phosphoric acid and pyrolyzed at 450oC in the retention of Zn, Cd and Pb using contaminated individual solutions. The experiment was performed using samples of activated carbon of eucalyptus husk (CCA), eucalyptus husk biochar (BC), activated carbon of sugar cane bagasse (CBA) and sugar cane bagasse biochar (BB) previously treated with Zn, Cd (range of tested solution from 0.1 up to 12 mmol L-1) and Pb (from 0.1 up 50 mmol L-1) which were submitted to stirring with ammonium acetate solution at pH 4.9 for 48 h. The results obtained were adjusted with Langmuir desorptiom isotherms. The pH of the resulting solution, were the meatls were analyse, was measure and remained in the range 4.9 - 5.0. The lower pH found in activated samples (range 2.4-2.5) resulted in larger desorption of metals than the biochar samples (pH of 9.7 for BC and 7.0 for BB). This result is surprising since for the biochar samples it was expected that any precipated metals were dissolved by the desorption solution in addition to metals released by ion exchange. Although the desorption results of activated samoels is still unclear, hich we belive may be explaibed by some adicitonal insterumental analysis, biochar samples showed better potential for application in contaminated soils than the previous.

  1. Production of activated carbon from biodiesel solid residues: An alternative for hazardous metal sorption from aqueous solution.

    PubMed

    Ribeiro, Rita F L; Soares, Vitor C; Costa, Letícia M; Nascentes, Clésia C

    2015-10-01

    In this study, the potential for the sorption of Pb(2+) and Cd(2+) from aqueous solutions using HNO3-treated activated carbon (TAC) obtained from radish press cake (Raphanus sativus L.), a solid residue from biodiesel production, was investigated. Activated carbon (AC) was obtained by physical activation with CO2(g). Chemical modification with HNO3 was employed to increase the sorption capability of the AC. The sorption of Pb(2+) and Cd(2+) was studied in monometallic systems in equilibrium with different metal-ion concentrations (10-400 mg L(-1)). The experimental sorption equilibrium data were fit to the Langmuir and Freundlich isotherm models. The maximum sorption capacity (qmax) obtained for AC from the Langmuir isotherm was 45.5 mg g(-1) for Cd(2+) and 250 mg g(-1) for Pb(2+). Moreover, TAC presented qmax of 166.7 mg g(-1) (1.48 mmol g(-1)) for Cd(2+) and 500.0 mg g(-1) (2.41 mmol g(-1)) for Pb(2+)showing the effect of chemical modification. Sorption-desorption studies showed that the interaction between metals and TAC is reversible and this sorbent can be reused for several consecutive cycles. Furthermore, the sorption of Cd(2+) and Pb(2+) by TAC was not affected by the presence of competing ions. The experimental data obtained in this study indicated that this solid residue is viable for the production of sorbents that remove metals, such as cadmium and lead, from wastewaters and thereby contribute to the sustainable development of the production of biodiesel. PMID:26233585

  2. PEGylated single-walled carbon nanotubes activate neutrophils to increase production of hypochlorous acid, the oxidant capable of degrading nanotubes

    SciTech Connect

    Vlasova, Irina I.; Vakhrusheva, Tatyana V.; Sokolov, Alexey V.; Kostevich, Valeria A.; Research Institute for Experimental Medicine, Russian Academy of Medical Science, Saint Petersburg ; Gusev, Alexandr A.; Gusev, Sergey A.; Melnikova, Viktoriya I.; Lobach, Anatolii S.

    2012-10-01

    Perspectives for the use of carbon nanotubes in biomedical applications depend largely on their ability to degrade in the body into products that can be easily cleared out. Carboxylated single-walled carbon nanotubes (c-SWCNTs) were shown to be degraded by oxidants generated by peroxidases in the presence of hydrogen peroxide. In the present study we demonstrated that conjugation of poly(ethylene glycol) (PEG) to c-SWCNTs does not interfere with their degradation by peroxidase/H{sub 2}O{sub 2} system or by hypochlorite. Comparison of different heme-containing proteins for their ability to degrade PEG-SWCNTs has led us to conclude that the myeloperoxidase (MPO) product hypochlorous acid (HOCl) is the major oxidant that may be responsible for biodegradation of PEG-SWCNTs in vivo. MPO is secreted mainly by neutrophils upon activation. We hypothesize that SWCNTs may enhance neutrophil activation and therefore stimulate their own biodegradation due to MPO-generated HOCl. PEG-SWCNTs at concentrations similar to those commonly used in in vivo studies were found to activate isolated human neutrophils to produce HOCl. Both PEG-SWCNTs and c-SWCNTs enhanced HOCl generation from isolated neutrophils upon serum-opsonized zymosan stimulation. Both types of nanotubes were also found to activate neutrophils in whole blood samples. Intraperitoneal injection of a low dose of PEG-SWCNTs into mice induced an increase in percentage of circulating neutrophils and activation of neutrophils and macrophages in the peritoneal cavity, suggesting the evolution of an inflammatory response. Activated neutrophils can produce high local concentrations of HOCl, thereby creating the conditions favorable for degradation of the nanotubes. -- Highlights: ► Myeloperoxidase (MPO) product hypochlorous acid is able to degrade CNTs. ► PEGylated SWCNTs stimulate isolated neutrophils to produce hypochlorous acid. ► SWCNTs are capable of activating neutrophils in blood samples. ► Activation of neutrophils in blood causes an increase in plasma MPO concentration. ► Intraperitoneal injection of PEG-SWCNTs in mice induces an inflammatory response.

  3. Activated Carbon Catalysts for the Production of Hydrogen for the Sulfur-Iodine Thermochemical Water Splitting Cycle

    SciTech Connect

    Lucia M. Petkovic; Daniel M. Ginosar; Harry W. Rollins; Kyle C Burch; Cristina Deiana; Hugo S. Silva; Maria F. Sardella; Dolly Granados

    2009-05-01

    Seven activated carbon catalysts obtained from a variety of raw material sources and preparation methods were examined for their catalytic activity to decompose hydroiodic acid (HI) to produce hydrogen; a key reaction in the sulfur-iodine (S-I) thermochemical water splitting cycle. Activity was examined under a temperature ramp from 473 to 773 K. Within the group of ligno-cellulosic steam-activated carbon catalysts, activity increased with surface area. However, both a mineral-based steam-activated carbon and a ligno-cellulosic chemically-activated carbon displayed activities lower than expected based on their higher surface areas. In general, ash content was detrimental to catalytic activity while total acid sites, as determined by Bohem’s titrations, seemed to favor higher catalytic activity within the group of steam-activated carbons. These results suggest, one more time, that activated carbon raw materials and preparation methods may have played a significant role in the development of surface characteristics that eventually dictated catalyst activity and stability as well.

  4. Effect of Carbon, Nitrogen Sources and Water Activity on Growth and Ochratoxin Production of Aspergillus carbonarius (Bainier) Thom

    PubMed Central

    Hashem, Abeer; Fathi Abd-Allah, Elsayed; Sultan Al-Obeed, Rashid; Abdullah Alqarawi, Abdulaziz; Alwathnani, Hend Awad

    2015-01-01

    Background: Ochratoxin A (OTA) is a toxic secondary metabolite produced by fungi belonging to Aspergillus and Penicillium genera. The production of OTA is influenced by environmental conditions and nutritional requirements. The postharvest application of bunches of table grape fruit (TGF), with water activity of 0.8 aw, was highly effective for controlling OTA contamination in vitro and in vivo (table grape). Objectives: The aim of this study was to determine the influence of environmental conditions and nutritional requirements on growth and OTA production by Aspergillus carbonarius, as well as, the impact of water activity on OTA production and growth characters of A. carbonarius. Furthermore, we also examined the influence of the application of different levels of water activity (aw 0.8) on the preservation of the general appearance of TGF and control of their contamination with OTA. Materials and Methods: The growth and OTA production by A. carbonarius were studied using glucose-ammonium nitrate salt broth medium. Effect of water activity was studied using glycerol (0.80, 0.85, 0.90, and 0.98 aw). The bunches of table grape fruits were immersed in glycerol solution (equivalent to 0.80 aw) and placed as a double layer in cardboard boxes (25 35 10 cm). The boxes were stored at 20C for 15 days to simulate local market conditions. Results: The maximum OTA production by A. carbonarius was observed on broth medium after eight days of incubation at 20C, with pH 4, and fructose and ammonium nitrate supplementation as carbon and nitrogen sources, respectively. The water activity (0.9, 0.85 aw) caused significant decrease in OTA production by A. carbonarius. The postharvest application of water activity (0.8 aw) was highly effective for maintenance of the table grape quality, which was expressed as weight loss, firmness and decay, while it also controlled OTA contamination of fruits under concept of local market conditions. Conclusions: Our results reported that deterioration of TGF by A. carbonarius could be minimized by application of aw. Our experiments were performed under conditions of local markets, which support the economy of many thousands of families in Egypt, especially in the poor rural areas. In future adequate research is required to use these technologies commercially. PMID:25825649

  5. Production of biodiesel fuel from canola oil with dimethyl carbonate using an active sodium methoxide catalyst prepared by crystallization.

    PubMed

    Kai, Takami; Mak, Goon Lum; Wada, Shohei; Nakazato, Tsutomu; Takanashi, Hirokazu; Uemura, Yoshimitsu

    2014-07-01

    In this study, a novel method for the production of biodiesel under mild conditions using fine particles of sodium methoxide formed in dimethyl carbonate (DMC) is proposed. Biodiesel is generally produced from vegetable oils by the transesterification of triglycerides with methanol. However, this reaction produces glycerol as a byproduct, and raw materials are not effectively utilized. Transesterification with DMC has recently been studied because glycerol is not formed in the process. Although solid-state sodium methoxide has been reported to be inactive for this reaction, the catalytic activity dramatically increased with the preparation of fine catalyst powders by crystallization. The transesterification of canola oil with DMC was studied using this catalyst for the preparation of biodiesel. A conversion greater than 96% was obtained at 65C for 2h with a 3:1M ratio of DMC and oil and 2.0 wt% catalyst. PMID:24813567

  6. DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by-products (DBPS) including total organic halide, trihalomethanes, haloacetic acids, haloacentonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along with ...

  7. DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    The effects of the use of the alternative disinfectants on the formation of halogenated disinfection byproducts (DBPs) including total organic halide, trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along ...

  8. Carbon, nitrogen and pH regulate the production and activity of a polygalacturonase isozyme produced by Penicillium expansum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of carbon, nitrogen and pH on polygalacturonase activity produced by Penicillium expansum were investigated. P. expansum mycelial growth was greatest on lyophilized fruit tissue and the highest PG activity occurred in apple pectin medium. Nitrogen source influenced PG activity and was ...

  9. Activated Carbon Derived from Fast Pyrolysis Liquids Production of Agricultural Residues and Energy Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fast pyrolysis is a thermochemical method that can be used for processing energy crops such as switchgrass, alfalfa, soybean straw, corn stover as well as agricultural residuals (broiler litter) for bio-oil production. Researchers with the Agriculture Research Service (ARS) of the USDA developed a 2...

  10. Production and characterization of activated carbon prepared from safflower seed cake biochar and its ability to absorb reactive dyestuff

    NASA Astrophysics Data System (ADS)

    Ang?n, Dilek; Kse, T. Ennil; Selengil, U?ur

    2013-09-01

    The use of activated carbon obtained from biochar for the removal of reactive dyestuff from aqueous solutions at various contact times, pHs and temperatures was investigated. The biochar was chemically modified with potassium hydroxide. The surface area and micropore volume of activated carbon was 1277 m2/g and 0.4952 cm3/g, respectively. The surface characterization of both biochar and activated carbon was undertaken using by Fourier transform infrared spectroscopy and scanning electron microscopy. The experimental data indicated that the adsorption isotherms are well described by the Dubinin-Radushkevich (DR) isotherm equation. The adsorption kinetics of reactive dyestuff obeys the pseudo second-order kinetic model. The thermodynamic parameters such as ?G?, ?H? and ?S? were calculated to estimate the nature of adsorption. The activation energy of the system was calculated as 1.12 kJ/mol. According to these results, prepared activated carbon could be used as a low-cost adsorbent to compare with the commercial activated carbon for the removal reactive dyestuff from wastewater.

  11. Reducing carbon dioxide to products

    DOEpatents

    Cole, Emily Barton; Sivasankar, Narayanappa; Parajuli, Rishi; Keets, Kate A

    2014-09-30

    A method reducing carbon dioxide to one or more products may include steps (A) to (C). Step (A) may bubble said carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode may reduce said carbon dioxide into said products. Step (B) may adjust one or more of (a) a cathode material, (b) a surface morphology of said cathode, (c) said electrolyte, (d) a manner in which said carbon dioxide is bubbled, (e), a pH level of said solution, and (f) an electrical potential of said divided electrochemical cell, to vary at least one of (i) which of said products is produced and (ii) a faradaic yield of said products. Step (C) may separate said products from said solution.

  12. Determining activated carbon performance

    SciTech Connect

    Naylor, W.F.; Rester, D.O.

    1995-07-01

    This article discusses the key elements involved in evaluating a system`s performance. Empty bed contact time (EBCT) is a term used to describe the length of time a liquid stream being treated is in contact with a granular activated carbon bed. The EBCT is the time required for a fluid to pass through the volume equivalent of the media bed, without the media being present. In a bed of granular activated carbon, the void volume or space between particles is usually about 45 percent. Therefore, the EBCT is about twice the true or actual time of contact between the fluid being treated and the GAC particles. The EBCT plays an important role in determining the effectiveness and longevity of granular activated carbon (GAC) used to treat liquids in a fixed-bed adsorber. Factors that influence and are influenced by EBCT, and their relationship to GAC performance in a treatment scheme include: adsorption, mass transfer zone, impurity concentration, adsorption affinity, flow rate and system design considerations.

  13. POWDERED ACTIVATED CARBON FROM NORTH DAKOTA LIGNITE: AN OPTION FOR DISINFECTION BY-PRODUCT CONTROL IN WATER TREATMENT PLANTS

    SciTech Connect

    Daniel J. Stepan; Thomas A. Moe; Melanie D. Hetland; Margaret L. Laumb

    2001-06-01

    New federal drinking water regulations have been promulgated to restrict the levels of disinfection by-products (DBPs) in finished public water supplies. DBPs are suspected carcinogens and are formed when organic material is partially oxidized by disinfectants commonly used in the water treatment industry. Additional federal mandates are expected in the near future that will further affect public water suppliers with respect to DBPs. Powdered activated carbon (PAC) has traditionally been used by the water treatment industry for the removal of compounds contributing to taste and odor problems. PAC also has the potential to remove naturally occurring organic matter (NOM) from raw waters prior to disinfection, thus controlling the formation of regulated DBPs. Many small water systems are currently using PAC for taste and odor control and have the potential to use PAC for controlling DBPs. This project, a cooperative effort between the Energy & Environmental Research Center (EERC), the Grand Forks Water Treatment Plant, and the University of North Dakota Department of Civil Engineering, consists of several interrelated tasks. The objective of the research was to evaluate a cost-effective PAC produced from North Dakota lignite for removing NOM from water and reducing trihalomethane formation potential. The research approach was to develop a statistically valid testing protocol that can be used to compare dose-response relationships between North Dakota lignite-derived PAC and commercially available PAC products. A statistical analysis was performed to determine whether significant correlations exist between operating conditions, water properties, PAC properties, and dose-response behavior. Pertinent physical and chemical properties were also measured for each of the waters and each of the PACs.

  14. Upgrading the rice husk char obtained by flash pyrolysis for the production of amorphous silica and high quality activated carbon.

    PubMed

    Alvarez, Jon; Lopez, Gartzen; Amutio, Maider; Bilbao, Javier; Olazar, Martin

    2014-10-01

    The overall valorization of rice husk char obtained by flash pyrolysis in a conical spouted bed reactor (CSBR) has been studied in a two-step process. Thus, silica has been recovered in a first step and the remaining carbon material has been subjected to steam activation. The char samples used in this study have been obtained by continuous flash pyrolysis in a conical spouted bed reactor at 500C. Extraction with Na2CO3 allows recovering 88% of the silica contained in the rice husk char. Activation of the silica-free rice husk char has been carried out in a fixed bed reactor at 800C using steam as activating agent. The porous structure of the activated carbons produced includes a combination of micropores and mesopores, with a BET surface area of up to 1365m(2)g(-1) at the end of 15min. PMID:25127010

  15. COMBINED USE OF ION EXCHANGE RESINS AND GRANULAR ACTIVATED CARBON FOR THE CONTROL OF ORGANIC MATTER AND DISINFECTION BY PRODUCTS

    EPA Science Inventory

    The use of anion exchange resin as a pretreatment step to granular activated carbon is evaluated. erformance is evaluated by DOC, SAC, TOXFP, and THMFP parameters. hio River water and Palm Beach groundwater are used. he results show that resin pretreatment is significant in exten...

  16. FREUNDLICH ADSORPTION ISOTHERMS OF AGRICULTURAL BY-PRODUCT-BASED POWDERED ACTIVATED CARBONS IN A GEOSMIN-WATER SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present study was designed to model the adsorption of geosmin from water under laboratory conditions using the Freundlich isotherm model. This model was used to compare the efficiency of sugarcane bagasse and pecan shell-based granular activated carbon (GAC) to the efficiency of a coal-based co...

  17. Commercial Activated Carbon for the Catalytic Production of Hydrogen via the Sulfur-Iodine Thermochemical Water Splitting Cycle

    SciTech Connect

    Daniel M. Ginosar; Lucia M. Petkovic; Kyle C. Burch

    2011-07-01

    Eight activated carbon catalysts were examined for their catalytic activity to decompose hydroiodic acid (HI) to produce hydrogen; a key reaction in the sulfur-iodine (S-I) thermochemical water splitting cycle. Activity was examined under a temperature ramp from 473 to 773 K. No statistically significant correlation was found between catalyst sample properties and catalytic activity. Four of the eight samples were examined for one week of continuous operation at 723 K. All samples appeared to be stable over the period of examination.

  18. 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.

  19. 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 oxides of nitrogen.

  20. 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 of sorption sites. The effect of pH on adsorption was investigated using buffered solutions. The sorption capacity decreased with increasing pH. A study of the effect of activation conditions on the adsorption capacity of the resulting carbon showed that steam activation at 750 C provides the optimum activity with the high-sodium char. An attempt to scale up the carbon production to the 2-kg scale failed to produce the same high activity that was obtained in the 100-g batch unit. Although this research demonstrated that a highly active carbon for water treatment can be produced from high-sodium lignites, much further work is needed to understand what methods and equipment will be needed for large-scale production of this carbon.

  1. Carbon Dioxide Effects on Ethanol Production, Pyruvate Decarboxylase, and Alcohol Dehydrogenase Activities in Anaerobic Sweet Potato Roots 1

    PubMed Central

    Chang, Ling A.; Hammett, Larry K.; Pharr, David M.

    1983-01-01

    The effect of varied anaerobic atmospheres on the metabolism of sweet potato (Ipomoea batatas [L.] Lam.) roots was studied. The internal gas atmospheres of storage roots changed rapidly when the roots were submerged under water. O2 and N2 gases disappeared quickly and were replaced by CO2. There were no appreciable differences in gas composition among the four cultivars that were studied. Under different anaerobic conditions, ethanol concentration in the roots was highest in a CO2 environment, followed by submergence and a N2 environment in all the cultivars except one. A positive relationship was found between ethanol production and pyruvate decarboxylase activity from both 100% CO2-treated and 100% N2-treated roots. CO2 atmospheres also resulted in higher pyruvate decarboxylase activity than did N2 atmospheres. Concentrations of CO2 were higher within anaerobic roots than those in the ambient anaerobic atmosphere. The level of pyruvate decarboxylase and ethanol in anaerobic roots was proportional to the ambient CO2 concentration. The measurable activity of pyruvate decarboxylase that was present in the roots was about 100 times less than that of alcohol dehydrogenase. Considering these observations, it is suggested that the rate-limiting enzyme for ethanol biosynthesis in sweet potato storage roots under anoxia is likely to be pyruvate decarboxylase rather than alcohol dehydrogenase. PMID:16662798

  2. The influence of broiler activity, growth rate, and litter on carbon dioxide balances for the determination of ventilation flow rates in broiler production.

    PubMed

    Calvet, S; Estellés, F; Cambra-López, M; Torres, A G; Van den Weghe, H F A

    2011-11-01

    Carbon dioxide balances are useful in determining ventilation rates in livestock buildings. These balances need an accurate estimation of the CO(2) produced by animals and their litter to determine the ventilation flows. To estimate the daily variation in ventilation flow, it is necessary to precisely know the daily variation pattern of CO(2) production, which mainly depends on animal activity. The objective of this study was to explore the applicability of CO(2) balances for determining ventilation flows in broiler buildings. More specifically, this work aimed to quantify the amount of CO(2) produced by the litter, as well as the amount of CO(2) produced by the broilers, as a function of productive parameters, and to analyze the influence of broiler activity on CO(2) emissions. Gas concentrations and ventilation flows were simultaneously measured in 3 trials, with 1 under experimental conditions and the other 2 in a commercial broiler farm. In the experimental assay, broiler activity was also determined. At the end of the experimental trial, on the day after the removal of the broilers, the litter accounted for 20% of the total CO(2) produced, and the broilers produced 3.71 L/h of CO(2) per kg of metabolic weight. On the commercial farm, CO(2) production was the same for the 2 cycles (2.60 L/h per kg of metabolic weight, P > 0.05). However, substantial differences were found between CO(2) and broiler activity patterns after changes in light status. A regression model was used to explain these differences (R(2) = 0.52). Carbon dioxide increased with bird activity, being on average 3.02 L/h per kg of metabolic weight for inactive birds and 4.73 L/h per kg of metabolic weight when bird activity was highest. Overall, CO(2) balances are robust tools for determining the daily average ventilation flows in broiler farms. These balances could also be applied at more frequent intervals, but in this case, particular care is necessary after light status changes because of discrepancy between animal activity and CO(2) production. PMID:22010228

  3. 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.

  4. REACTIONS OF CHLORITE WITH ACTIVATED CARBON AND WITH VANILLIC ACID AND INDAN ADSORBED ON ACTIVATED CARBON

    EPA Science Inventory

    The reaction between chlorite (CO2(-1)) and vanillic acid, at pH 6.0 in the presence of granular activated carbon (GAC), yielded several reaction products identifiable by GC/MS; no products were found in the absence of GAC. Indan and ClO2 or ClO2(-1) reacted in aqueous solution a...

  5. Multiwalled carbon nanotubes induce a fibrogenic response by stimulating reactive oxygen species production, activating NF-?B signaling, and promoting fibroblast-to-myofibroblast transformation.

    PubMed

    He, Xiaoqing; Young, Shih-Houng; Schwegler-Berry, Diane; Chisholm, William P; Fernback, Joseph E; Ma, Qiang

    2011-12-19

    Carbon nanotubes (CNTs) are novel materials with unique electronic and mechanical properties. The extremely small size, fiberlike shape, large surface area, and unique surface chemistry render their distinctive chemical and physical characteristics and raise potential hazards to humans. Several reports have shown that pulmonary exposure to CNTs caused inflammation and lung fibrosis in rodents. The molecular mechanisms that govern CNT lung toxicity remain largely unaddressed. Here, we report that multiwalled carbon nanotubes (MWCNTs) have potent, dose-dependent toxicity on cultured human lung cells (BEAS-2B, A549, and WI38-VA13). Mechanistic analyses were carried out at subtoxic doses (?20 ?g/mL, ? 24 h). MWCNTs induced substantial ROS production and mitochondrial damage, implicating oxidative stress in cellular damage by MWCNT. MWCNTs activated the NF-?B signaling pathway in macrophages (RAW264.7) to increase the secretion of a panel of cytokines and chemokines (TNF?, IL-1?, IL-6, IL-10, and MCP1) that promote inflammation. Activation of NF-?B involved rapid degradation of I?B?, nuclear accumulation of NF-?Bp65, binding of NF-?B to specific DNA-binding sequences, and transactivation of target gene promoters. Finally, MWCNTs induced the production of profibrogenic growth factors TGF?1 and PDGF from macrophages that function as paracrine signals to promote the transformation of lung fibroblasts (WI38-VA13) into myofibroblasts, a key step in the development of fibrosis. Our results revealed that MWCNTs elicit multiple and intertwining signaling events involving oxidative damage, inflammatory cytokine production, and myofibroblast transformation, which potentially underlie the toxicity and fibrosis in human lungs by MWCNTs. PMID:22081859

  6. Production of graphitic carbon-based nanocomposites from K2CO3-activated coconut shells as counter electrodes for dye-sensitized solar-cell applications

    NASA Astrophysics Data System (ADS)

    Loryuenyong, Vorrada; Buasri, Achanai; Lerdvilainarit, Parichat; Manachevakulm, Konnatee; Sompong, Siripond

    2016-01-01

    In this study, graphitic carbon-activated carbon nanocomposites fabricated from K2CO3 chemically-activated coconut shells by using Fe-catalytic chemical vapor deposition are reported. The present method was simple, environmentally-friendly, low cost, but successfully offered graphitic carbon-based materials that demonstrated promise for use as counter electrodes in dye-sensitized solar cells. The results showed that the coconut shell:catalyst ratio (1:0, 1:4, 1:1, and 4:1) significantly affected the structural, physical and electrochemical properties of the samples. Graphitic carbon and activated carbon nanocomposites with a high specific surface area of 1230 m2/g and high electrochemical activity in iodide reduction are obtained for samples with a coconut shells/iron precursor (Fe(NO3)3) ratio of 4:1.

  7. Production Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Gallaway, Ann, Ed.

    This production systems guide provides teachers with learning activities for secondary students. Introductory materials include an instructional planning outline and worksheet, an outline of essential elements, domains and objectives, a course description, and a content outline. The guide contains 30 modules on the following topics: production

  8. A carbon sink pathway increases carbon productivity in cyanobacteria.

    PubMed

    Oliver, John W K; Atsumi, Shota

    2015-05-01

    The burning of fossil reserves, and subsequent release of carbon into the atmosphere is depleting the supply of carbon-based molecules used for synthetic materials including plastics, oils, medicines, and glues. To provide for future society, innovations are needed for the conversion of waste carbon (CO2) into organic carbon useful for materials. Chemical production directly from photosynthesis is a nascent technology, with great promise for capture of CO2 using sunlight. To improve low yields, it has been proposed that photosynthetic capacity can be increased by a relaxation of bottlenecks inherent to growth. The limits of carbon partitioning away from growth within the cell and the effect of partitioning on carbon fixation are not well known. Here we show that expressing genes in a pathway between carbon fixation and pyruvate increases partitioning to 2,3-butanediol (23BD) and leads to a 1.8-fold increase in total carbon yield in the cyanobacterium Synechococcus elongatus PCC 7942. Specific 2,3-butanediol production increases 2.4-fold. As partitioning increases beyond 30%, it leads to a steep decline in total carbon yield. The data suggests a local maximum for carbon partitioning from the Calvin Benson cycle that is scalable with light intensity. PMID:25777135

  9. Rerouting Carbon Flux To Enhance Photosynthetic Productivity

    SciTech Connect

    Ducat, DC; Avelar-Rivas, JA; Way, JC; Silver, PA

    2012-03-23

    The bioindustrial production of fuels, chemicals, and therapeutics typically relies upon carbohydrate inputs derived from agricultural plants, resulting in the entanglement of food and chemical commodity markets. We demonstrate the efficient production of sucrose from a cyanobacterial species, Synechococcus elongatus, heterologously expressing a symporter of protons and sucrose (cscB). cscB-expressing cyanobacteria export sucrose irreversibly to concentrations of >10 mM without culture toxicity. Moreover, sucrose-exporting cyanobacteria exhibit increased biomass production rates relative to wild-type strains, accompanied by enhanced photosystem II activity, carbon fixation, and chlorophyll content. The genetic modification of sucrose biosynthesis pathways to minimize competing glucose-or sucrose-consuming reactions can further improve sucrose production, allowing the export of sucrose at rates of up to 36.1 mg liter(-1) h illumination(-1). This rate of production exceeds that of previous reports of targeted, photobiological production from microbes. Engineered S. elongatus produces sucrose in sufficient quantities (up to similar to 80% of total biomass) such that it may be a viable alternative to sugar synthesis from terrestrial plants, including sugarcane.

  10. Rerouting Carbon Flux To Enhance Photosynthetic Productivity

    PubMed Central

    Ducat, Daniel C.; Avelar-Rivas, J. Abraham; Way, Jeffrey C.

    2012-01-01

    The bioindustrial production of fuels, chemicals, and therapeutics typically relies upon carbohydrate inputs derived from agricultural plants, resulting in the entanglement of food and chemical commodity markets. We demonstrate the efficient production of sucrose from a cyanobacterial species, Synechococcus elongatus, heterologously expressing a symporter of protons and sucrose (cscB). cscB-expressing cyanobacteria export sucrose irreversibly to concentrations of >10 mM without culture toxicity. Moreover, sucrose-exporting cyanobacteria exhibit increased biomass production rates relative to wild-type strains, accompanied by enhanced photosystem II activity, carbon fixation, and chlorophyll content. The genetic modification of sucrose biosynthesis pathways to minimize competing glucose- or sucrose-consuming reactions can further improve sucrose production, allowing the export of sucrose at rates of up to 36.1 mg liter?1 h illumination?1. This rate of production exceeds that of previous reports of targeted, photobiological production from microbes. Engineered S. elongatus produces sucrose in sufficient quantities (up to ?80% of total biomass) such that it may be a viable alternative to sugar synthesis from terrestrial plants, including sugarcane. PMID:22307292

  11. PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS

    SciTech Connect

    Dady Dadyburjor; Chong Chen; Elliot B. Kennel; Liviu Magean; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

    2006-02-23

    The purpose of this DOE-funded effort is to develop technologies for carbon products from coal-derived feedstocks. Carbon products can include precursor materials such as solvent extracted carbon ore (SECO) and synthetic pitch (Synpitch). In addition, derived products include carbon composites, fibers, foams and others. Key milestones included producing hydrogenated coal in the Hydrotreating Facility for the first time. The facility is now operational, although digital controls have not yet been completely wired. In addition, ultrasound is being used to investigate enhanced dissolution of coal. Experiments have been carried out.

  12. 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.

  13. 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.

  14. 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.

  15. Food security and climate change: on the potential to adapt global crop production by active selection to rising atmospheric carbon dioxide

    PubMed Central

    Ziska, Lewis H.; Bunce, James A.; Shimono, Hiroyuki; Gealy, David R.; Baker, Jeffrey T.; Newton, Paul C. D.; Reynolds, Matthew P.; Jagadish, Krishna S. V.; Zhu, Chunwu; Howden, Mark; Wilson, Lloyd T.

    2012-01-01

    Agricultural production is under increasing pressure by global anthropogenic changes, including rising population, diversion of cereals to biofuels, increased protein demands and climatic extremes. Because of the immediate and dynamic nature of these changes, adaptation measures are urgently needed to ensure both the stability and continued increase of the global food supply. Although potential adaption options often consider regional or sectoral variations of existing risk management (e.g. earlier planting dates, choice of crop), there may be a global-centric strategy for increasing productivity. In spite of the recognition that atmospheric carbon dioxide (CO2) is an essential plant resource that has increased globally by approximately 25 per cent since 1959, efforts to increase the biological conversion of atmospheric CO2 to stimulate seed yield through crop selection is not generally recognized as an effective adaptation measure. In this review, we challenge that viewpoint through an assessment of existing studies on CO2 and intraspecific variability to illustrate the potential biological basis for differential plant response among crop lines and demonstrate that while technical hurdles remain, active selection and breeding for CO2 responsiveness among cereal varieties may provide one of the simplest and direct strategies for increasing global yields and maintaining food security with anthropogenic change. PMID:22874755

  16. Production Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Gallaway, Ann, Ed.

    This production systems guide provides teachers with learning activities for secondary students. Introductory materials include an instructional planning outline and worksheet, an outline of essential elements, domains and objectives, a course description, and a content outline. The guide contains 30 modules on the following topics: production…

  17. 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.

  18. 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.

  19. Phenol adsorption by activated carbon produced from spent coffee grounds.

    PubMed

    Castro, Cnthia S; Abreu, Anelise L; Silva, Carmen L T; Guerreiro, Mrio C

    2011-01-01

    The present work highlights the preparation of activated carbons (ACs) using spent coffee grounds, an agricultural residue, as carbon precursor and two different activating agents: water vapor (ACW) and K(2)CO(3) (ACK). These ACs presented the microporous nature and high surface area (620-950 m(2) g(-1)). The carbons, as well as a commercial activated carbon (CAC) used as reference, were evaluated as phenol adsorbent showing high adsorption capacity (?150 mg g(-1)). The investigation of the pH solution in the phenol adsorption was also performed. The different activating agents led to AC with distinct morphological properties, surface area and chemical composition, although similar phenol adsorption capacity was verified for both prepared carbons. The production of activated carbons from spent coffee grounds resulted in promising adsorbents for phenol removal while giving a noble destination to the residue. PMID:22105129

  20. Mercury binding on activated carbon

    SciTech Connect

    Bihter Padak; Michael Brunetti; Amanda Lewis; Jennifer Wilcox

    2006-11-15

    Density functional theory has been employed for the modeling of activated carbon (AC) using a fused-benzene ring cluster approach. Oxygen functional groups have been investigated for their promotion of effective elemental mercury binding on AC surface sites. Lactone and carbonyl functional groups yield the highest mercury binding energies. Further, the addition of halogen atoms has been considered to the modeled surface, and has been found to increase the AC's mercury adsorption capacity. The mercury binding energies increase with the addition of the following halogen atoms, F {gt} Cl {gt} Br {gt} I, with the fluorine addition being the most promising halogen for increasing mercury adsorption.

  1. System and method for coproduction of activated carbon and steam/electricity

    DOEpatents

    Srinivasachar, Srivats; Benson, Steven; Crocker, Charlene; Mackenzie, Jill

    2011-07-19

    A system and method for producing activated carbon comprising carbonizing a solid carbonaceous material in a carbonization zone of an activated carbon production apparatus (ACPA) to yield a carbonized product and carbonization product gases, the carbonization zone comprising carbonaceous material inlet, char outlet and carbonization gas outlet; activating the carbonized product via activation with steam in an activation zone of the ACPA to yield activated carbon and activation product gases, the activation zone comprising activated carbon outlet, activation gas outlet, and activation steam inlet; and utilizing process gas comprising at least a portion of the carbonization product gases or a combustion product thereof; at least a portion of the activation product gases or a combustion product thereof; or a combination thereof in a solid fuel boiler system that burns a solid fuel boiler feed with air to produce boiler-produced steam and flue gas, the boiler upstream of an air heater within a steam/electricity generation plant, said boiler comprising a combustion zone, a boiler-produced steam outlet and at least one flue gas outlet.

  2. Preparation and characterization of activated carbon produced from pomegranate seeds by ZnCl 2 activation

    NASA Astrophysics Data System (ADS)

    Uar, Suat; Erdem, Murat; Tay, Turgay; Karagz, Selhan

    2009-08-01

    In this study, pomegranate seeds, a by-product of fruit juice industry, were used as precursor for the preparation of activated carbon by chemical activation with ZnCl 2. The influence of process variables such as the carbonization temperature and the impregnation ratio on textural and chemical-surface properties of the activated carbons was studied. When using the 2.0 impregnation ratio at the carbonization temperature of 600 C, the specific surface area of the resultant carbon is as high as 978.8 m 2 g -1. The results showed that the surface area and total pore volume of the activated carbons at the lowest impregnation ratio and the carbonization temperature were achieved as high as 709.4 m 2 g -1 and 0.329 cm 3 g -1. The surface area was strongly influenced by the impregnation ratio of activation reagent and the subsequent carbonization temperature.

  3. The enhanced removal of carbonaceous and nitrogenous disinfection by-product precursors using integrated permanganate oxidation and powdered activated carbon adsorption pretreatment.

    PubMed

    Chu, Wenhai; Yao, Dechang; Gao, Naiyun; Bond, Tom; Templeton, Michael R

    2015-12-01

    Pilot-scale tests were performed to reduce the formation of a range of carbonaceous and nitrogenous disinfection by-products (C-, N-DBPs), by removing or transforming their precursors, with an integrated permanganate oxidation and powdered activated carbon adsorption (PM-PAC) treatment process before conventional water treatment processes (coagulation-sedimentation-filtration, abbreviated as CPs). Compared with the CPs, PM-PAC significantly enhanced the removal of DOC, DON, NH3(+)-N, and algae from 52.9%, 31.6%, 71.3%, and 83.6% to 69.5%, 61.3%, 92.5%, and 97.5%, respectively. PM pre-oxidation alone and PAC pre-adsorption alone did not substantially reduce the formation of dichloroacetonitrile, trichloroacetonitrile, N-nitrosodimethylamine and dichloroacetamide. However, the PM-PAC integrated process significantly reduced the formation of both C-DBPs and N-DBPs by 60-90% for six C-DBPs and 64-93% for six N-DBPs, because PM oxidation chemically altered the molecular structures of nitrogenous organic compounds and increased the adsorption capacity of the DBP precursors, thus highlighting a synergistic effect of PM and PAC. PM-PAC integrated process is a promising drinking water technology for the reduction of a broad spectrum of C-DBPs and N-DBPs. PMID:26065622

  4. Fractal analysis of granular activated carbons using isotherm data

    SciTech Connect

    Khalili, N.R.; Pan, M.; Sandi, G.

    1997-08-01

    Utilization of adsorption on solid surfaces was exercised for the first time in 1785. Practical application of unactivated carbon filters, and powdered carbon were first demonstrated in the American water treatment plant, and a municipal treatment plant in New Jersey, in 1883 and 1930, respectively. The use of activated carbon became widespread in the next few decades. At present, adsorption on carbons has a wide spread application in water treatment and removal of taste, odor, removal of synthetic organic chemicals, color-forming organics, and desinfection by-products and their naturally occurring precursors. This paper presents an analysis of the surface fractal dimension and adsorption capacity of a group of carbons.

  5. PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS

    SciTech Connect

    Dady Dadyburjor; Philip R. Biedler; Chong Chen; L. Mitchell Clendenin; Manoj Katakdaunde; Elliot B. Kennel; Nathan D. King; Liviu Magean; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

    2004-08-31

    This Department of Energy National Energy Technology Laboratory sponsored project developed carbon products, using mildly hydrogenated solvents to extract the organic portion of coal to create synthetic pitches, cokes, carbon foam and carbon fibers. The focus of this effort was on development of lower cost solvents, milder hydrogenation conditions and improved yield in order to enable practical production of these products. This technology is needed because of the long-term decline in production of domestic feedstocks such as petroleum pitch and coal tar pitch. Currently, carbon products represents a market of roughly 5 million tons domestically, and 19 million tons worldwide. Carbon products are mainly derived from feedstocks such as petroleum pitch and coal tar pitch. The domestic supply of petroleum pitch is declining because of the rising price of liquid fuels, which has caused US refineries to maximize liquid fuel production. As a consequence, the long term trend has a decline in production of petroleum pitch over the past 20 years. The production of coal tar pitch, as in the case of petroleum pitch, has likewise declined significantly over the past two decades. Coal tar pitch is a byproduct of metallurgical grade coke (metcoke) production. In this industry, modern metcoke facilities are recycling coal tar as fuel in order to enhance energy efficiency and minimize environmental emissions. Metcoke production itself is dependent upon the production requirements for domestic steel. Hence, several metcoke ovens have been decommissioned over the past two decades and have not been replaced. As a consequence sources of coal tar are being taken off line and are not being replaced. The long-term trend is a reduction in coal tar pitch production. Thus import of feedstocks, mainly from Eastern Europe and China, is on the rise despite the relatively large transportation cost. To reverse this trend, a new process for producing carbon products is needed. The process must be economically competitive with current processes, and yet be environmentally friendly as well. The solvent extraction process developed uses mild hydrogenation of low cost oils to create powerful solvents that can dissolve the organic portion of coal. The insoluble portion, consisting mainly of mineral matter and fixed carbon, is removed via centrifugation or filtration, leaving a liquid solution of coal chemicals and solvent. This solution can be further refined via distillation to meet specifications for products such as synthetic pitches, cokes, carbon foam and fibers. The most economical process recycles 85% of the solvent, which itself is obtained as a low-cost byproduct from industrial processes such as coal tar or petroleum refining. Alternatively, processes have been developed that can recycle 100% of the solvent, avoiding any need for products derived from petroleum or coal tar.

  6. Sorption of petroleum products by carbon sorbents

    SciTech Connect

    M.A. Perederii; Y.I. Kurakov; I.N. Malikov; S.V. Molchanov

    2009-07-01

    A comparative study of the adsorption of petroleum products by micro- and macroporous carbon sorbents was performed. For this purpose, four carbon sorbent samples prepared from various raw materials by various processing techniques were used. The following raw materials were used: (1) fuel mill from the Mezinoskoe deposit; (2) wood waste, shaving and sawdust in ratio (%) of 50:50; and (3) low-caking gas coal of the 2G group from the mine im.Kirova in the Kuznetsk Basin. The pore structures and adsorption capacities of these sorbents for petroleum products were studied. It was found that the adsorption of petroleum products on porous and nonporous carbon sorbents occurred in different manners. In this case, macroporous sorbents with a weakly developed structure of sorbing micro- and mesopores exhibited a maximum capacity for petroleum products.

  7. Production of bio-based phenolic resin and activated carbon from bio-oil and biochar derived from fast pyrolysis of palm kernel shells.

    PubMed

    Choi, Gyung-Goo; Oh, Seung-Jin; Lee, Soon-Jang; Kim, Joo-Sik

    2015-02-01

    A fraction of palm kernel shells (PKS) was pyrolyzed in a fluidized bed reactor. The experiments were performed in a temperature range of 479-555 °C to produce bio-oil, biochar, and gas. All the bio-oils were analyzed quantitatively and qualitatively by GC-FID and GC-MS. The maximum content of phenolic compounds in the bio-oil was 24.8 wt.% at ∼500 °C. The maximum phenol content in the bio-oil, as determined by the external standard method, was 8.1 wt.%. A bio-oil derived from the pyrolysis of PKS was used in the synthesis of phenolic resin, showing that the bio-oil could substitute for fossil phenol up to 25 wt.%. The biochar was activated using CO2 at a final activation temperature of 900 °C with different activation time (1-3 h) to produce activated carbon. Activated carbons produced were microporous, and the maximum surface area of the activated carbons produced was 807 m(2)/g. PMID:25227587

  8. 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.

  9. Adsorption of herbicides using activated carbons

    SciTech Connect

    Derbyshire, F.; Jagtoyan, M.; Lafferty, C.; Kimber, G.

    1996-10-01

    This work describes development of a series of novel activated carbon materials and their testing for possible water treatment applications by studying the adsorption of sodium pentachlorphenolate, PCP (a common herbicide/wood preservative). Although the application of activated carbons is an established technology for the treatment of public water supplies, there is a growing need for materials with higher selectivity and adsorptive capacities as well as high abrasion resistance. The materials that will be discussed include extruded wood-derived carbons with novel pore size distributions and high hardness, as well as activated carbon fiber composites. Comparisons will be made with commercial granular water treatment carbons.

  10. Nanostructural activated carbons for hydrogen storage

    NASA Astrophysics Data System (ADS)

    Li, Suoding

    A series of nanostructured activated carbons have been synthesized from poly(ether ether ketone) (PEEK), and its derivatives. These carbons, with surface area exceeding 3000 m2/g and with average pore diameters of ? 20 A, are proven to be superior hydrogen storage materials, with hydrogen storage capacities up to 5.5 wt% at 77 K and 45 atm. The porous texture of these carbons was controlled via optimizing three synthetic steps: thermo-oxidation of PEEK in air, pyrolysis or carbonization of the oxidized PEEK in an inert atmosphere, and activation of the pre-carbonized PEEK with metal hydroxide. Thermo-oxidation of PEEK and carbonization process were thoroughly studied. These processes have been investigated by MDSC, FTIR, TGA and Py-MS. The pyrolysis or carbonization of PEEK involves the degradation of PEEK chains in three stages. Carbon morphology, including crystallinity and porous texture, is readily controlled by adjusting carbonization temperature. Activation of PEEK carbons, using inorganic bases and other activation agents, produces microporous carbons having a very narrow pore size distribution and an average pore diameter of ? 20 A. The activation control parameters including activation agent, activation temperature, time and carbon morphology have been investigated extensively. High surface area activated carbon is obtained by activating a highly amorphous carbon with a high activation agent/carbon ratio at 800C. Theoretical calculations show that the pores with smaller diameter, especially smaller than 7 A, favor hydrogen adsorption. The experimental results confirm this fact and show that: (1) the hydrogen adsorption capacity per unit surface area at 77 K and 1 bar is larger in the smaller pores, (2) gravimetric hydrogen storage capacity (W(H2)) is directly proportional to the ultramicropore (< 7 A) volume; and (3) the volumetric hydrogen storage capacity is directly proportional to the volume fraction of ultramicropores in carbon. Hydrogen adsorption in activated carbons synthesized from PEEK and poly(ether imide) blends, poly(phenylene oxide), polybenzimidazole and lignin show similar trends. In addition, W( H2) progressively increases as surface area increases for the carbons with similar average pore diameters. Keywords. carbon, activated carbon, poly(ether ether ketone), poly(ether imide), poly(phenylene oxide), polybenzimidazole, lignin, gas adsorption, hydrogen storage

  11. The Formation of Carbon Nanofibers on Powdered Activated Carbon Impregnated with Nickel

    NASA Astrophysics Data System (ADS)

    Ahmed, Y. M.; Al-Mamun, A. A.; Muyibi, S. A.; Al-Khatib, M. F. R.; Jameel, A. T.; AlSaadi, M. A.

    2009-06-01

    In the present work, the production and characterization of carbon nanofibers (CNFs) composite is reported. Carbon nanofibers (CNF) were produced on powdered activated carbon PAC—impregnated with nickel—by Chemical Vapor Deposition (CVD) of a hydrocarbon in the presence of hydrogen at ˜780° C. The flow rates of carbon source and hydrogen were fixed. The CNFs were formed directly over the impregnated AC. Variable weight percentage ratios of the catalyst salt (Ni+2) were used for the impregnation (1, 3, 5, 7 and 9%, respectively). The product displays a relatively high surface area, essentially constituted by the external surface, and the absence of the bottled pores encountered with activated carbon. FSEM, TEM and TGA were used for the characterization of the product.

  12. Remove organics by activated carbon adsorption

    SciTech Connect

    Stenzel, M.H. )

    1993-04-01

    Activated carbon has a wide variety of applications in the chemical process industries (CPI), one of which is water and wastewater treatment. Activated carbon is especially effective at removing soluble organic compounds (SOCs) from both surface and groundwater sources. This article focuses on the use of granular activated carbon to remove specific compounds from water sources. It provides a methodology to evaluate adsorption, establish a process design, develop a system design, and estimate preliminary capital and operating costs.

  13. SORPTION OF ELEMENTAL MERCURY BY ACTIVATED CARBONS

    EPA Science Inventory

    The mechanisms and rate of elemental mercury (HgO) capture by activated carbons have been studied using a bench-scale apparatus. Three types of activated carbons, two of which are thermally activated (PC-100 and FGD) and one with elemental sulfur (S) impregnated in it (HGR), were...

  14. Solubility product of OH-carbonated hydroxyapatite.

    PubMed

    Ito, A; Maekawa, K; Tsutsumi, S; Ikazaki, F; Tateishi, T

    1997-09-15

    Information on the solubility of OH-carbonated hydroxyapatite, Ca10(PO4)6(CO3)x(OH)2-2x, previously has not been available. In the present study the solubility product (Ksp) of OH-carbonated hydroxyapatite was measured in a 0.1 M acetic acid and sodium acetate buffer solution in a pH range of 4.0-5.8 at a CO2 partial pressure of 10(-3.52) atm. The equilibrium solubility increased with the increase of carbonate content. The Ksp values decreased with the decrease of pH. For example, Ksps were 10(-119), 10(-123), and 10(-130) for pure hydroxyapatite at pH 4.9, 4.5, and 4.1, respectively. The decrease of Ksp was not accounted for by calcium-carbonate complexation. Ksp measured at isoelectric points (L) was expressed as pL = 118.65 - 0.47316 x (CO2 wt%)2.4176. From this formula, the L values were calculated for pure and fully carbonated hydroxyapatite as 10(-118.7) and 10(102.8), respectively. The L value for pure hydroxyapatite agreed with values measured under carbonate-free conditions. Therefore, the L values were regarded as the Ksp for OH-carbonated hydroxyapatite excluding errors arising from carbonate contamination in the solution. PMID:9294768

  15. Studies and characterisations of various activated carbons used for carbon/carbon supercapacitors

    NASA Astrophysics Data System (ADS)

    Gamby, J.; Taberna, P. L.; Simon, P.; Fauvarque, J. F.; Chesneau, M.

    Various activated carbons from the PICA Company have been tested in supercapacitor cells in order to compare their performances. The differences measured in terms of specific capacitance and cell resistance are presented. Porosity measurements made on activated carbon powders and electrode allowed a better understanding of the electrochemical behaviour of these activated carbons. In this way, the PICACTIF SC carbon was found to be an interesting active material for supercapacitors, with a specific capacitance as high as 125 F/g.

  16. Carbon Footprint Analysis for a GRAPE Production Case Study

    NASA Astrophysics Data System (ADS)

    Sirca, C.; Marras, S.; Masia, S.; Duce, P.; Zara, P.; Spano, D.

    2013-12-01

    Agriculture activities can play a double role in emitting or sequestering carbon from the atmosphere. Mitigation of greenhouse gas (GHG) emissions in agriculture is one of the most urgent research subjects in the framework of enhancing environmental stewardship. However, little is known about the role of the agriculture in the global carbon balance, since most of the studies applied the Eddy Covariance technique in natural or semi-natural ecosystems to investigate their role in mitigate the anthropogenic carbon release. The application of the Eddy Covariance technique in agricultural systems could greatly improve our knowledge about their role on the global carbon budget and help in modeling the related processes. In addition, there is a growing request from producers, trade companies, and customers on the assessment of the environmental impact of a production process related to agricultural high quality products. In recent years, particular attention was put on the estimation of GHG emissions deriving from productive processes. In this context, a useful tool is the Life Cycle Assessment (LCA), which represents a methodology to estimate GHG emissions related to the entire life cycle of a product. The Carbon Footprint (CF) analysis represents a subset of the LCA, which only considers CO2 emissions with an impact on climate change. With respect to the wine industry, most of studies focused on the CF analysis related to the wine making process in the cellar, while a few studies analyzed the GHG emissions related to the grape production. The aim of this work was to quantify the CO2 emissions due to the grape production and emphasize the double role of a vineyard as a carbon sink or source. An Eddy Covariance station was set up in a representative vineyard located in the Mediterranean Basin (Sardinia, Italy) to measure the net carbon exchange between the surface and the atmosphere. The CF analysis was also conducted to compute the carbon balance of the grape production process in terms of CO2-equivalent emissions by following the International Wine Carbon Protocol (IWCP). Additional terms (e.g. emissions due to fossil fuel combustion, fertilizers, soil tillage) were also quantified. Results showed that the vineyard is able to store net amounts of carbon both in biomass and soil. Human added inputs for the vineyard management practices (e.g. soil tillage) are responsible for the release of significant quantities of GHG in the atmosphere. Results also showed that data obtained from the EC measurements could allow for a direct quantification of part of the terms involved in the grape production process, but the assessment of the carbon sequestration capacity in agricultural sites requires to account for GHG emissions from additional anthropogenic inputs.

  17. Selecting activated carbon for water and wastewater treatability studies

    SciTech Connect

    Zhang, W.; Chang, Q.G.; Liu, W.D.; Li, B.J.; Jiang, W.X.; Fu, L.J.; Ying, W.C.

    2007-10-15

    A series of follow-up investigations were performed to produce data for improving the four-indicator carbon selection method that we developed to identify high-potential activated carbons effective for removing specific organic water pollutants. The carbon's pore structure and surface chemistry are dependent on the raw material and the activation process. Coconut carbons have relatively more small pores than large pores; coal and apricot nutshell/walnut shell fruit carbons have the desirable pore structures for removing adsorbates of all sizes. Chemical activation, excessive activation, and/or thermal reactivation enlarge small pores, resulting in reduced phenol number and higher tannic acid number. Activated carbon's phenol, iodine, methylene blue, and tannic acid numbers are convenient indicators of its surface area and pore volume of pore diameters < 10, 10-15, 15-28, and > 28 angstrom, respectively. The phenol number of a carbon is also a good indicator of its surface acidity of oxygen-containing organic functional groups that affect the adsorptive capacity for aromatic and other small polar organics. The tannic acid number is an indicator of carbon's capacity for large, high-molecular-weight natural organic precursors of disinfection by-products in water treatment. The experimental results for removing nitrobenzene, methyl-tert-butyl ether, 4,4-bisphenol, humic acid, and the organic constituents of a biologically treated coking-plant effluent have demonstrated the effectiveness of this capacity-indicator-based method of carbon selection.

  18. Integrating Steel Production with Mineral Carbon Sequestration

    SciTech Connect

    Klaus Lackner; Paul Doby; Tuncel Yegulalp; Samuel Krevor; Christopher Graves

    2008-05-01

    The objectives of the project were (i) to develop a combination iron oxide production and carbon sequestration plant that will use serpentine ores as the source of iron and the extraction tailings as the storage element for CO2 disposal, (ii) the identification of locations within the US where this process may be implemented and (iii) to create a standardized process to characterize the serpentine deposits in terms of carbon disposal capacity and iron and steel production capacity. The first objective was not accomplished. The research failed to identify a technique to accelerate direct aqueous mineral carbonation, the limiting step in the integration of steel production and carbon sequestration. Objective (ii) was accomplished. It was found that the sequestration potential of the ultramafic resource surfaces in the US and Puerto Rico is approximately 4,647 Gt of CO2 or over 500 years of current US production of CO2. Lastly, a computer model was developed to investigate the impact of various system parameters (recoveries and efficiencies and capacities of different system components) and serpentinite quality as well as incorporation of CO2 from sources outside the steel industry.

  19. Accelerated adsorption with activated carbon fiber

    SciTech Connect

    Pimenov, A.V.; Lieberman, A.I.; Shmidt, J.L.; Cheh, H.Y.

    1995-09-01

    The properties of a new type of polyamphoteric activated carbon fiber (ACF) were investigated theoretically and experimentally. Results are compared with those from granular activated carbon (GAC) and ion-exchange resin (IER) materials. The adsorption rate of ACF was found to be two orders of magnitude higher than that of the GAC and one order of magnitude higher than that of the IER.

  20. Merging allylic carbon-hydrogen and selective carbon-carbon bond activation

    NASA Astrophysics Data System (ADS)

    Masarwa, Ahmad; Didier, Dorian; Zabrodski, Tamar; Schinkel, Marvin; Ackermann, Lutz; Marek, Ilan

    2014-01-01

    Since the nineteenth century, many synthetic organic chemists have focused on developing new strategies to regio-, diastereo- and enantioselectively build carbon-carbon and carbon-heteroatom bonds in a predictable and efficient manner. Ideal syntheses should use the least number of synthetic steps, with few or no functional group transformations and by-products, and maximum atom efficiency. One potentially attractive method for the synthesis of molecular skeletons that are difficult to prepare would be through the selective activation of C-H and C-C bonds, instead of the conventional construction of new C-C bonds. Here we present an approach that exploits the multifold reactivity of easily accessible substrates with a single organometallic species to furnish complex molecular scaffolds through the merging of otherwise difficult transformations: allylic C-H and selective C-C bond activations. The resulting bifunctional nucleophilic species, all of which have an all-carbon quaternary stereogenic centre, can then be selectively derivatized by the addition of two different electrophiles to obtain more complex molecular architecture from these easily available starting materials.

  1. Natural gas storage with activated carbon from a bituminous coal

    USGS Publications Warehouse

    Sun, Jielun; Rood, M.J.; Rostam-Abadi, M.; Lizzio, A.A.

    1996-01-01

    Granular activated carbons ( -20 + 100 mesh; 0.149-0.84 mm) were produced by physical activation and chemical activation with KOH from an Illinois bituminous coal (IBC-106) for natural gas storage. The products were characterized by BET surface area, micropore volume, bulk density, and methane adsorption capacities. Volumetric methane adsorption capacities (Vm/Vs) of some of the granular carbons produced by physical activation are about 70 cm3/cm3 which is comparable to that of BPL, a commercial activated carbon. Vm/Vs values above 100 cm3/cm3 are obtainable by grinding the granular products to - 325 mesh (<0.044 mm). The increase in Vm/Vs is due to the increase in bulk density of the carbons. Volumetric methane adsorption capacity increases with increasing pore surface area and micropore volume when normalizing with respect to sample bulk volume. Compared with steam-activated carbons, granular carbons produced by KOH activation have higher micropore volume and higher methane adsorption capacities (g/g). Their volumetric methane adsorption capacities are lower due to their lower bulk densities. Copyright ?? 1996 Elsevier Science Ltd.

  2. Create a Consortium and Develop Premium Carbon Products from Coal

    SciTech Connect

    Frank Rusinko; John Andresen; Jennifer E. Hill; Harold H. Schobert; Bruce G. Miller

    2006-01-01

    The objective of these projects was to investigate alternative technologies for non-fuel uses of coal. Special emphasis was placed on developing premium carbon products from coal-derived feedstocks. A total of 14 projects, which are the 2003 Research Projects, are reported herein. These projects were categorized into three overall objectives. They are: (1) To explore new applications for the use of anthracite in order to improve its marketability; (2) To effectively minimize environmental damage caused by mercury emissions, CO{sub 2} emissions, and coal impounds; and (3) To continue to increase our understanding of coal properties and establish coal usage in non-fuel industries. Research was completed in laboratories throughout the United States. Most research was performed on a bench-scale level with the intent of scaling up if preliminary tests proved successful. These projects resulted in many potential applications for coal-derived feedstocks. These include: (1) Use of anthracite as a sorbent to capture CO{sub 2} emissions; (2) Use of anthracite-based carbon as a catalyst; (3) Use of processed anthracite in carbon electrodes and carbon black; (4) Use of raw coal refuse for producing activated carbon; (5) Reusable PACs to recycle captured mercury; (6) Use of combustion and gasification chars to capture mercury from coal-fired power plants; (7) Development of a synthetic coal tar enamel; (8) Use of alternative binder pitches in aluminum anodes; (9) Use of Solvent Extracted Carbon Ore (SECO) to fuel a carbon fuel cell; (10) Production of a low cost coal-derived turbostratic carbon powder for structural applications; (11) Production of high-value carbon fibers and foams via the co-processing of a low-cost coal extract pitch with well-dispersed carbon nanotubes; (12) Use of carbon from fly ash as metallurgical carbon; (13) Production of bulk carbon fiber for concrete reinforcement; and (14) Characterizing coal solvent extraction processes. Although some of the projects funded did not meet their original goals, the overall objectives of the CPCPC were completed as many new applications for coal-derived feedstocks have been researched. Future research in many of these areas is necessary before implementation into industry.

  3. Oxygen reduction activity of carbon nitride supported on carbon nanotubes.

    PubMed

    Lyth, S M; Nabae, Y; Islam, N M; Kuroki, S; Kakimoto, M; Miyata, S

    2012-06-01

    Fuel cells offer an alternative to burning fossil fuels, but use platinum as a catalyst which is expensive and scarce. Cheap, alternative catalysts could enable fuel cells to become serious contenders in the green energy sector. One promising class of catalyst for electrochemical oxygen reduction is iron-containing, nanostructured, nitrogen-doped carbon. The catalytic activity of such N-doped carbons has improved vastly over the years bringing industrial applications ever closer. Stoichiometric carbon nitride powder has only been observed in recent years. It has nitrogen content up to 57% and as such is an extremely interesting material to work with. The electrochemical activity of carbon nitride has already been explored, confirming that iron is not a necessary ingredient for 4-electron oxygen reduction. Here, we synthesize carbon nitride on a carbon nanotube support and subject it to high temperature treatment in an effort to increase the surface area and conductivity. The results lend insight into the mechanism of oxygen reduction and show the potential for carbon nanotube-supported carbon nitride to be used as a catalyst to replace platinum in fuel cells. PMID:22905547

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Abdullah, N.; Rinaldi, A.; Muhammad, I. S.; Hamid, S. B. Abd.; 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 C for an hour in each step. The catalytic growth of nanocarbon in C2H4/H2 was carried out at temperature of 550 C for 2 hrs with different rotating angle in the fluidization system. SEM and N2 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.

  6. Effects of carbon fibers on consumer products

    NASA Technical Reports Server (NTRS)

    Wise, R. A.; Lovett, C. D.

    1980-01-01

    The potential effects of carbon fibers on consumer products such as dishwashers, microwave ovens, and smoke detectors were investigated. The investigation was divided into two categories to determine the potential faults and hazards that could occur if fibers should enter the electrical circuits of the selected appliances. The categories were a fault analysis and a hazard analysis. Hazards considered were fire, flood, physical harm, explosion, and electrical shock. Electrical shock was found to be a possible occurrence related to carbon fibers. Faults were considered to be any effect on the performance of an appliance which would result in complaint or require service action.

  7. 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%.

  8. Carbon nanotube mass production: principles and processes.

    PubMed

    Zhang, Qiang; Huang, Jia-Qi; Zhao, Meng-Qiang; Qian, Wei-Zhong; Wei, Fei

    2011-07-18

    Our society requires new materials for a sustainable future, and carbon nanotubes (CNTs) are among the most important advanced materials. This Review describes the state-of-the-art of CNT synthesis, with a focus on their mass-production in industry. At the nanoscale, the production of CNTs involves the self-assembly of carbon atoms into a one-dimensional tubular structure. We describe how this synthesis can be achieved on the macroscopic scale in processes akin to the continuous tonne-scale mass production of chemical products in the modern chemical industry. Our overview includes discussions on processing methods for high-purity CNTs, and the handling of heat and mass transfer problems. Manufacturing strategies for agglomerated and aligned single-/multiwalled CNTs are used as examples of the engineering science of CNT production, which includes an understanding of their growth mechanism, agglomeration mechanism, reactor design, and process intensification. We aim to provide guidelines for the production and commercialization of CNTs. Although CNTs can now be produced on the tonne scale, knowledge of the growth mechanism at the atomic scale, the relationship between CNT structure and application, and scale-up of the production of CNTs with specific chirality are still inadequate. A multidisciplinary approach is a prerequisite for the sustainable development of the CNT industry. PMID:21732544

  9. Copper (II) Adsorption by Activated Carbons from Pecan Shells: Effect of Oxygen Level During Activation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural by-products represent a considerable quantity of harvested commodity crops. The use of by-products as precursors for the production of widely used adsorbents, such as activated carbons, may impart a value-added component of the overall biomass harvested. Our objective in this paper is...

  10. 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.

  11. Tracking urban carbon footprints from production and consumption perspectives

    NASA Astrophysics Data System (ADS)

    Lin, Jianyi; Hu, Yuanchao; Cui, Shenghui; Kang, Jiefeng; Ramaswami, Anu

    2015-05-01

    Cities are hotspots of socio-economic activities and greenhouse gas emissions. The aim of this study was to extend the research range of the urban carbon footprint (CF) to cover emissions embodied in products traded among regions and intra-city sectors. Using Xiamen City as a study case, the total urban-related emissions were evaluated, and the carbon flows among regions and intra-city sectors were tracked. Then five urban CF accountings were evaluated, including purely geographic accounting (PGA), community-wide infrastructure footprint (CIF), and consumption-based footprint (CBF) methods, as well as the newly defined production-based footprint (PBF) and purely production footprint (PPF). Research results show that the total urban-related emissions of Xiamen City in 2010 were 55.2 Mt CO2e/y, of which total carbon flow among regions or intra-city sectors accounted for 53.7 Mt CO2e/y. Within the total carbon flow, import and export respectively accounted for 59 and 65%, highlighting the importance of emissions embodied in trade. By regional trade balance, North America and Europe were the largest net carbon exported-to regions, and Mainland China and Taiwan the largest net carbon imported-from regions. Among intra-sector carbon flows, manufacturing was the largest emission-consuming sector of the total urban carbon flow, accounting for 77.4, and 98% of carbon export was through industrial products trade. By the PBF, PPF, CIF, PGA and CBF methods, the urban CFs were respectively 53.7 Mt CO2e/y, 44.8 Mt CO2e/y, 28.4 Mt CO2e/y, 23.7 Mt CO2e/y, and 19.0 Mt CO2e/y, so all of the other four CFs were higher than the CBF. All of these results indicate that urban carbon mitigation must consider the supply chain management of imported goods, the production efficiency within the city, the consumption patterns of urban consumers, and the responsibility of the ultimate consumers outside the city.

  12. Quality of poultry litter-derived granular activated carbon.

    PubMed

    Qiu, Guannan; Guo, Mingxin

    2010-01-01

    Utilization of poultry litter as a source material for generating activated carbon is a value-added and environmentally beneficial approach to recycling organic waste. In this study, the overall quality of poultry litter-derived granular activated carbon was systematically evaluated based on its various physical and chemical properties. Granular activated carbon generated from pelletized poultry litter following a typical steam-activation procedure possessed numerous micropores in the matrix. The product exhibited a mean particle diameter of 2.59 mm, an apparent density of 0.45 g cm(-3), a ball-pan hardness of 91.0, an iodine number of 454 mg g(-1), and a BET surface area of 403 m(2) g(-1). It contained high ash, nitrogen, phosphorus contents and the trace elements Cu, Zn, and As. Most of the nutrients and toxic elements were solidified and solution-unextractable. In general, poultry litter-based activated carbon demonstrated overall quality comparable to that of low-grade commercial activated carbon derived from coconut shell and bituminous coal. It is promising to use poultry litter as a feedstock to manufacture activated carbon for wastewater treatment. PMID:19703765

  13. Adsorption of herbicides using activated carbons

    SciTech Connect

    Derbyshire, F.; Jagtoyen, M.; Lafferty, C.; Kimber, G.

    1996-12-31

    This paper describes the results of research in which novel activated carbons have been examined for their efficacy in water treatment and, specifically, for the adsorption of a common herbicide and wood preservative, sodium pentachlorophenolate. To place this work in context, the introduction will discuss first some of the considerations of using activated carbons for water treatment, and then certain aspects of the authors research that has led to this particular topic.

  14. Carbon-Sublimation Production of Fullerenes.

    NASA Astrophysics Data System (ADS)

    Tinker, Frank Albert

    1995-01-01

    Carbon-sublimation production of fullerenes enjoys wide use in both experimental and industrial application worldwide. Although it has been nearly five years since the inception of the technique, little is known about the roles various parameters play in the production process. This work attempts to shed light, both experimentally and theoretically, on the basic processes at work in this type of fullerene production. Experimental results herein show that a functional relationship exists among the C_{60 }, C_{70}, C_{76}, C_ {78}, and C_{84} fullerenes produced in carbon arcs. This result is interpreted to mean that an equilibrium description of the production process may be valid. Theoretical calculations are then offered in support of such a view. The theory goes on to show details of an equilibrium description that reproduce essential features of fullerene mass-spectra. It is shown that equilibrium abundances of n-atom -sized clusters are highly dependent on the stoichiometric equation chosen to describe the system. However, common traits of the investigated equilibrium descriptions lead to useful conclusions.

  15. Thermocatalytic process for CO.sub.2-free production of hydrogen and carbon from hydrocarbons

    DOEpatents

    Muradov, Nazim Z.

    2011-08-23

    A novel process and apparatus are disclosed for sustainable CO.sub.2-free production of hydrogen and carbon by thermocatalytic decomposition (dissociation, pyrolysis, cracking) of hydrocarbon fuels over carbon-based catalysts in the absence of air and/or water. The apparatus and thermocatalytic process improve the activity and stability of carbon catalysts during the thermocatalytic process and produce both high purity hydrogen (at least, 99.0 volume %) and carbon, from any hydrocarbon fuel, including sulfurous fuels. In a preferred embodiment, production of hydrogen and carbon is achieved by both internal and external activation of carbon catalysts. Internal activation of carbon catalyst is accomplished by recycling of hydrogen-depleted gas containing unsaturated and aromatic hydrocarbons back to the reactor. External activation of the catalyst can be achieved via surface gasification with hot combustion gases during catalyst heating. The process and apparatus can be conveniently integrated with any type of fuel cell to generate electricity.

  16. Nanospace engineering of KOH activated carbon.

    PubMed

    Romanos, J; Beckner, M; Rash, T; Firlej, L; Kuchta, B; Yu, P; Suppes, G; Wexler, C; Pfeifer, P

    2012-01-13

    This paper demonstrates that nanospace engineering of KOH activated carbon is possible by controlling the degree of carbon consumption and metallic potassium intercalation into the carbon lattice during the activation process. High specific surface areas, porosities, sub-nanometer (<1 nm) and supra-nanometer (1-5 nm) pore volumes are quantitatively controlled by a combination of KOH concentration and activation temperature. The process typically leads to a bimodal pore size distribution, with a large, approximately constant number of sub-nanometer pores and a variable number of supra-nanometer pores. We show how to control the number of supra-nanometer pores in a manner not achieved previously by chemical activation. The chemical mechanism underlying this control is studied by following the evolution of elemental composition, specific surface area, porosity, and pore size distribution during KOH activation and preceding H(3)PO(4) activation. The oxygen, nitrogen, and hydrogen contents decrease during successive activation steps, creating a nanoporous carbon network with a porosity and surface area controllable for various applications, including gas storage. The formation of tunable sub-nanometer and supra-nanometer pores is validated by sub-critical nitrogen adsorption. Surface functional groups of KOH activated carbon are studied by microscopic infrared spectroscopy. PMID:22156024

  17. Commercial Product Activation Using RFID

    NASA Technical Reports Server (NTRS)

    Jedrey, Thomas

    2008-01-01

    Radio-frequency identification (RFID) would be used for commercial product activation, according to a proposal. What is new here is the concept of combining RFID with activation - more specifically, using RFID for activating commercial products (principally, electronic ones) and for performing such ancillary functions as tracking individual product units on production lines, tracking shipments, and updating inventories. According to the proposal, an RFID chip would be embedded in each product. The information encoded in the chip would include a unique number for identifying the product. An RFID reader at the point of sale would record the number of the product and would write digital information to the RFID chip for either immediate activation of the product or for later interrogation and processing. To be practical, an RFID product-activation system should satisfy a number of key requirements: the system should be designed to be integrable into the inventory-tracking and the data-processing and -communication infrastructures of businesses along the entire supply chain from manufacture to retail; the system should be resistant to sophisticated hacking; activation codes should be made sufficiently complexity to minimize the probability of activating stolen products; RFID activation equipment at points of sale must be capable to two-way RF communication for the purposes of reading information from, and writing information to, embedded RFID chips; the equipment at points of sale should be easily operable by sales clerks with little or no training; the point-of-sale equipment should verify activation and provide visible and/or audible signals indicating verification or lack thereof; and, the system should be able to handle millions of products per year with minimal human intervention, among other requirements.

  18. Facile preparation of hierarchically porous carbon using diatomite as both template and catalyst and methylene blue adsorption of carbon products.

    PubMed

    Liu, Dong; Yuan, Peng; Tan, Daoyong; Liu, Hongmei; Wang, Tong; Fan, Mingde; Zhu, Jianxi; He, Hongping

    2012-12-15

    Hierarchically porous carbons were prepared using a facile preparation method in which diatomite was utilized as both template and catalyst. The porous structures of the carbon products and their formation mechanisms were investigated. The macroporosity and microporosity of the diatomite-templated carbons were derived from replication of diatom shell and structure-reconfiguration of the carbon film, respectively. The macroporosity of carbons was strongly dependent on the original morphology of the diatomite template. The macroporous structure composed of carbon plates connected by the pillar- and tube-like macropores resulted from the replication of the central and edge pores of the diatom shells with disk-shaped morphology, respectively. And another macroporous carbon tubes were also replicated from canoe-shaped diatom shells. The acidity of diatomite dramatically affected the porosity of the carbons, more acid sites of diatomite template resulted in higher surface area and pore volume of the carbon products. The diatomite-templated carbons exhibited higher adsorption capacity for methylene blue than the commercial activated carbon (CAC), although the specific surface area was much smaller than that of CAC, due to the hierarchical porosity of diatomite-templated carbons. And the carbons were readily reclaimed and regenerated. PMID:22999465

  19. Activated carbon for gas phase arsenic capture

    SciTech Connect

    Jadhav, R.; Gupta, H.; Misro, S.; Agnihotri, R.; Fan, L.S.

    1999-07-01

    Investigation of activated carbon as a multifunctional sorbent for trace metal capture is the focus of this study. In addition to mercury and halides, selenium and arsenic represent two of the most volatile trace species that remain in gas phase in substantial amounts. In this work, fundamental sorption characteristics of the activated carbon for arsenic removal from the gas phase are investigated. Activated carbons with different structural properties are studied for their usefulness in removing arsenic species from flue gas. Arsenic oxide (As{sub 2}O{sub 3}) is used as the source of arsenic. Preliminary sorption studies indicate that arsenic removal occurs by physical adsorption, with increased capture by carbons with higher surface areas.

  20. Catalysts for Efficient Production of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Sun, Ted X.; Dong, Yi

    2009-01-01

    Several metal alloys have shown promise as improved catalysts for catalytic thermal decomposition of hydrocarbon gases to produce carbon nanotubes (CNTs). Heretofore almost every experiment on the production of carbon nanotubes by this method has involved the use of iron, nickel, or cobalt as the catalyst. However, the catalytic-conversion efficiencies of these metals have been observed to be limited. The identification of better catalysts is part of a continuing program to develop means of mass production of high-quality carbon nanotubes at costs lower than those achieved thus far (as much as $100/g for purified multi-wall CNTs or $1,000/g for single-wall CNTs in year 2002). The main effort thus far in this program has been the design and implementation of a process tailored specifically for high-throughput screening of alloys for catalyzing the growth of CNTs. The process includes an integral combination of (1) formulation of libraries of catalysts, (2) synthesis of CNTs from decomposition of ethylene on powders of the alloys in a pyrolytic chemical-vapor-decomposition reactor, and (3) scanning- electron-microscope screening of the CNTs thus synthesized to evaluate the catalytic efficiencies of the alloys. Information gained in this process is put into a database and analyzed to identify promising alloy compositions, which are to be subjected to further evaluation in a subsequent round of testing. Some of these alloys have been found to catalyze the formation of carbon nano tubes from ethylene at temperatures as low as 350 to 400 C. In contrast, the temperatures typically required for prior catalysts range from 550 to 750 C.

  1. Microwave-assisted regeneration of activated carbon.

    PubMed

    Foo, K Y; Hameed, B H

    2012-09-01

    Microwave heating was used in the regeneration of methylene blue-loaded activated carbons produced from fibers (PFAC), empty fruit bunches (EFBAC) and shell (PSAC) of oil palm. The dye-loaded carbons were treated in a modified conventional microwave oven operated at 2450 MHz and irradiation time of 2, 3 and 5 min. The virgin properties of the origin and regenerated activated carbons were characterized by pore structural analysis and nitrogen adsorption isotherm. The surface chemistry was examined by zeta potential measurement and determination of surface acidity/basicity, while the adsorptive property was quantified using methylene blue (MB). Microwave irradiation preserved the pore structure, original active sites and adsorption capacity of the regenerated activated carbons. The carbon yield and the monolayer adsorption capacities for MB were maintained at 68.35-82.84% and 154.65-195.22 mg/g, even after five adsorption-regeneration cycles. The findings revealed the potential of microwave heating for regeneration of spent activated carbons. PMID:22728787

  2. 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

  3. 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.

  4. Stratigraphic framework of productive carbonate buildups

    SciTech Connect

    Greenlee, S.M.; Lehmann, P.J. )

    1990-05-01

    Hydrocarbon-productive carbonate buildups are found within a relatively narrow window of geologic time and stratigraphic settings. Because buildups are common exploration objectives in frontier and mature basins, an understanding of their stratigraphic occurrence permits them to be more accurately explored. Based on a worldwide survey, most production occurs in isolated periods of geologic time: Middle Silurian-Late Silurian, late Middle and Late Devonian, Late Pennsylvanian and Early Permian, Late Cretaceous, Paleocene, and Miocene. The authors results suggest that many factors of successful buildup plays are predictable on the basis of geohistory analysis and of basin-filling stratal patterns. Deposition of extensive source beds and thick buildups coincide with second-order eustatic rises. Other primary controls on the temporal distribution of buildups include reef-building organism type, mineralogy, and paleolatitude. Geohistory analysis indicates that periods immediately prior to or during the earliest portion of rapid increases of accommodation correspond to times of productive buildup growth. During this time, shelf margins step landward and buildups become progressively more areally restricted. Buildups eventually are unable to keep pace with high rates of accommodation increase and often are overlain by distal toes of clinoforms within regressive wedges deposited during subsequent periods with lower rates of accommodation increase. The result is a stratigraphic juxtaposition of mounded reservoir carbonate and deep-marine sealing shale. This basin-fill position accounts for over 70% of known buildup-reservoired hydrocarbons. Buildups deposited in overlying regressive wedges are often lower relief and prone to seal problems.

  5. Age differences in productive activities.

    PubMed

    Herzog, A R; Kahn, R L; Morgan, J N; Jackson, J S; Antonucci, T C

    1989-07-01

    Age differences in productive contributions through both paid and unpaid work are examined in commensurate terms. Data are from a nationwide household survey of 3,617 adults age 25 and older conducted in 1986. Older Americans participate in many unpaid productive activities at levels that are comparable to those reached by middle-aged and younger Americans; these activities include volunteer work in organizations, informal help to others, maintenance and repair of their home and possessions, and housework. Relatively few older Americans spend any time participating in paid work and unpaid rearing of children. Largely because of the cessation of paid work and child care, older Americans spend less time overall in productive activities. Women and men spend about equal time in productive activities, but women spend more of it in unpaid work and less of it in paid work. The difficulties with using paid work as the major indicator for describing productivity across the life span are discussed. PMID:2738316

  6. Chemical activation of gasification carbon residue for phosphate removal

    NASA Astrophysics Data System (ADS)

    Kilpimaa, Sari; Runtti, Hanna; Lassi, Ulla; Kuokkanen, Toivo

    2012-05-01

    Recycling of waste materials provides an economical and environmentally significant method to reduce the amount of waste. Bioash formed in the gasification process possesses a notable amount of unburned carbon and therefore it can be called a carbon residue. After chemical activation carbon residue could be use to replace activated carbon for example in wastewater purification processes. The effect of chemical activation process variables such as chemical agents and contact time in the chemical activation process were investigated. This study also explored the effectiveness of the chemically activated carbon residue for the removal of phosphate from an aqueous solution. The experimental adsorption study was performed in a batch reactor and the influence of adsorption time, initial phosphate concentration and pH was studied. Due to the carbon residue's low cost and high adsorption capacity, this type of waste has the potential to be utilised for the cost-effective removal of phosphate from wastewaters. Potential adsorbents could be prepared from these carbonaceous by-products and used as an adsorbent for phosphate removal.

  7. Flax shive as a source of activated carbon for metals remediaton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flax shive constitutes about 70% of the flax stem and has limited use. Because shive is a lignocellulosic by-product, it can potentially be pyroylzed and activated to produce an activated carbon. The objective of this study was to create an activated carbon from flax shive by chemical activation t...

  8. Biofuel intercropping effects on soil carbon and microbial activity.

    PubMed

    Strickland, Michael S; Leggett, Zakiya H; Sucre, Eric B; Bradford, Mark A

    2015-01-01

    Biofuels will help meet rising demands for energy and, ideally, limit climate change associated with carbon losses from the biosphere to atmosphere. Biofuel management must therefore maximize energy production and maintain ecosystem carbon stocks. Increasingly, there is interest in intercropping biofuels with other crops, partly because biofuel production on arable land might reduce availability and increase the price of food. One intercropping approach involves growing biofuel grasses in forest plantations. Grasses differ from trees in both their organic inputs to soils and microbial associations. These differences are associated with losses of soil carbon when grasses become abundant in forests. We investigated how intercropping switchgrass (Panicum virgalum), a major candidate for cellulosic biomass production, in loblolly pine (Pinus taeda) plantations affects soil carbon, nitrogen, and microbial dynamics. Our design involved four treatments: two pine management regimes where harvest residues (i.e., biomass) were left in place or removed, and two switchgrass regimes where the grass was grown with pine under the same two biomass scenarios (left or removed). Soil variables were measured in four 1-ha replicate plots in the first and second year following switchgrass planting. Under switchgrass intercropping, pools of mineralizable and particulate organic matter carbon were 42% and 33% lower, respectively. These declines translated into a 21% decrease in total soil carbon in the upper 15 cm of the soil profile, during early stand development. The switchgrass effect, however, was isolated to the interbed region where switchgrass is planted. In these regions, switchgrass-induced reductions in soil carbon pools with 29%, 43%, and 24% declines in mineralizable, particulate, and total soil carbon, respectively. Our results support the idea that grass inputs to forests can prime the activity of soil organic carbon degrading microbes, leading to net reductions in stocks of soil carbon. Active microbial biomass, however, is higher under switchgrass, and this microbial biomass is a dominant precursor of soil carbon formation. Future studies need to investigate soil carbon dynamics throughout the lifetime of intercropping rotations to evaluate whether increases in microbial biomass can offset initial declines in soil carbon, and hence, maintain ecosystem carbon stocks. PMID:26255363

  9. PYROGENIC ACTIVITY OF CARBON-FILTERED WATERS

    EPA Science Inventory

    The endotoxin content and pyrogenic response of granular activated carbon (GAC) filtered waters were studied. GAC-filtered secondary effluent from an activated sludge pilot plant contained free endotoxins in the range 6-250 micrograms/l yielding positive pyrogenic responses in 18...

  10. 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...

  11. Catalytic carbon membranes for hydrogen production

    SciTech Connect

    Damle, A.S.; Gangwal, S.K.

    1992-01-01

    Commercial carbon composite microfiltration membranes may be modified for gas separation applications by providing a gas separation layer with pores in the 1- to 10-nm range. Several organic polymeric precursors and techniques for depositing a suitable layer were investigated in this project. The in situ polymerization technique was found to be the most promising, and pure component permeation tests with membrane samples prepared with this technique indicated Knudsen diffusion behavior. The gas separation factors obtained by mixed-gas permeation tests were found to depend strongly on gas temperature and pressure indicating significant viscous flow at high-pressure conditions. The modified membranes were used to carry out simultaneous water gas shift reaction and product hydrogen separation. These tests indicated increasing CO conversions with increasing hydrogen separation. A simple process model was developed to simulate a catalytic membrane reactor. A number of simulations were carried out to identify operating conditions leading to product hydrogen concentrations over 90 percent. (VC)

  12. 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.

  13. MOLTEN CARBONATE FUEL CELL PRODUCT DESIGN IMPROVEMENT

    SciTech Connect

    H.C. Maru; M. Farooque

    2003-03-01

    The program efforts are focused on technology and system optimization for cost reduction, commercial design development, and prototype system field trials. The program is designed to advance the carbonate fuel cell technology from full-size field test to the commercial design. FuelCell Energy, Inc. (FCE) is in the later stage of the multiyear program for development and verification of carbonate fuel cell based power plants supported by DOE/NETL with additional funding from DOD/DARPA and the FuelCell Energy team. FCE has scaled up the technology to full-size and developed DFC{reg_sign} stack and balance-of-plant (BOP) equipment technology to meet product requirements, and acquired high rate manufacturing capabilities to reduce cost. FCE has designed submegawatt (DFC300A) and megawatt (DFC1500 and DFC3000) class fuel cell products for commercialization of its DFC{reg_sign} technology. A significant progress was made during the reporting period. The reforming unit design was optimized using a three-dimensional stack simulation model. Thermal and flow uniformities of the oxidant-In flow in the stack module were improved using computational fluid dynamics based flow simulation model. The manufacturing capacity was increased. The submegawatt stack module overall cost was reduced by {approx}30% on a per kW basis. An integrated deoxidizer-prereformer design was tested successfully at submegawatt scale using fuels simulating digester gas, coal bed methane gas and peak shave (natural) gas.

  14. Destruxin production of Metarhizium anisopliae under carbon and nitrogen exhaustion.

    TOXLINE Toxicology Bibliographic Information

    Wang H; Hutwimmer S; Strasser H; Burgstaller W

    2009-08-01

    Destruxins (dtx) A, B, and E, showing a variety of biological activities, are the main toxic secondary metabolites of the entomopathogenous ascomycete Metarhizium anisopliae Bipesco 5, a widely used biocontrol production strain. Dynamics of dtx biosynthesis were monitored during liquid fermentation in a chemically defined medium. During shake flask cultivation with excess carbon, nitrogen and phosphate, approximately 50, 20, and 100 mg l(-1) dtx A, B, and E were produced after 12 d. Destruxins were produced during exponential growth phase and in the stationary phase. Carbon exhaustion in the culture broth was demonstrated to affect destruxin production to a minor degree: Absolute dtx amounts in the liquid increased also after glucose exhaustion; dtx amounts referred to biomass increased further evidently in shake flasks or slightly in bioreactor experiments after carbon limitation occurred. Contrarily, nitrogen exhaustion resulted in an evident decline in dtx amounts referred to biomass. Absolute amounts in the culture broth, however, still increased slightly the following four days in bioreactor experiments. From this we conclude that dtx production is highly influenced by nitrogen availability. Generally, dtx production in bioreactors with controlled aeration (1 vvm) was significantly lower than in shake flasks.

  15. Destruxin production of Metarhizium anisopliae under carbon and nitrogen exhaustion.

    PubMed

    Wang, Hui; Hutwimmer, Stefan; Strasser, Hermann; Burgstaller, Wolfgang

    2009-08-01

    Destruxins (dtx) A, B, and E, showing a variety of biological activities, are the main toxic secondary metabolites of the entomopathogenous ascomycete Metarhizium anisopliae Bipesco 5, a widely used biocontrol production strain. Dynamics of dtx biosynthesis were monitored during liquid fermentation in a chemically defined medium. During shake flask cultivation with excess carbon, nitrogen and phosphate, approximately 50, 20, and 100 mg l(-1) dtx A, B, and E were produced after 12 d. Destruxins were produced during exponential growth phase and in the stationary phase. Carbon exhaustion in the culture broth was demonstrated to affect destruxin production to a minor degree: Absolute dtx amounts in the liquid increased also after glucose exhaustion; dtx amounts referred to biomass increased further evidently in shake flasks or slightly in bioreactor experiments after carbon limitation occurred. Contrarily, nitrogen exhaustion resulted in an evident decline in dtx amounts referred to biomass. Absolute amounts in the culture broth, however, still increased slightly the following four days in bioreactor experiments. From this we conclude that dtx production is highly influenced by nitrogen availability. Generally, dtx production in bioreactors with controlled aeration (1 vvm) was significantly lower than in shake flasks. PMID:19322833

  16. Photobiological hydrogen production and carbon dioxide sequestration

    NASA Astrophysics Data System (ADS)

    Berberoglu, Halil

    Photobiological hydrogen production is an alternative to thermochemical and electrolytic technologies with the advantage of carbon dioxide sequestration. However, it suffers from low solar to hydrogen energy conversion efficiency due to limited light transfer, mass transfer, and nutrient medium composition. The present study aims at addressing these limitations and can be divided in three parts: (1) experimental measurements of the radiation characteristics of hydrogen producing and carbon dioxide consuming microorganisms, (2) solar radiation transfer modeling and simulation in photobioreactors, and (3) parametric experiments of photobiological hydrogen production and carbon dioxide sequestration. First, solar radiation transfer in photobioreactors containing microorganisms and bubbles was modeled using the radiative transport equation (RTE) and solved using the modified method of characteristics. The study concluded that Beer-Lambert's law gives inaccurate results and anisotropic scattering must be accounted for to predict the local irradiance inside a photobioreactor. The need for accurate measurement of the complete set of radiation characteristics of microorganisms was established. Then, experimental setup and analysis methods for measuring the complete set of radiation characteristics of microorganisms have been developed and successfully validated experimentally. A database of the radiation characteristics of representative microorganisms have been created including the cyanobacteria Anabaena variabilis, the purple non-sulfur bacteria Rhodobacter sphaeroides and the green algae Chlamydomonas reinhardtii along with its three genetically engineered strains. This enabled, for the first time, quantitative assessment of the effect of genetic engineering on the radiation characteristics of microorganisms. In addition, a parametric experimental study has been performed to model the growth, CO2 consumption, and H 2 production of Anabaena variabilis as functions of irradiance and CO2 concentration. Kinetic models were successfully developed based on the Monod model and on a novel scaling analysis employing the CO2 consumption half-time as the time scale. Finally, the growth and hydrogen production of Anabaena variabilis have been compared in a flat panel photobioreactor using three different nutrient media under otherwise similar conditions. Light to hydrogen energy conversion efficiency for Allen-Arnon medium was superior by a factor of 5.5 to both BG-11 and BG-11o media. This was attributed to the presence of vanadium and larger heterocyst frequency observed in the Allen-Arnon medium.

  17. Carbon sequestration from boreal wildfires via Pyrogenic Carbon production

    NASA Astrophysics Data System (ADS)

    Santin, Cristina; Doerr, Stefan; Preston, Caroline

    2014-05-01

    Fire releases important quantities of carbon (C) to the atmosphere. Every year, an average of 460 Million ha burn around the globe, generating C emissions equivalent to a third of the current annual contribution from fossil fuel combustion. Over the longer-term wildfires are widely considered as 'net zero C emission events', because C emissions from fires, excluding those associated with deforestation and peatland fires, are balanced by C uptake by regenerating vegetation. This 'zero C emission' scenario, however, may be flawed, as it does not consider the production of pyrogenic C (PyC). During fire, part of the biomass C burnt is emitted to the atmosphere but part is transformed into PyC (i.e. charcoal). The enhanced resistance of PyC to environmental degradation compared to unburnt biomass gives it the potential to sequester C over the medium/long term. Therefore, after complete regeneration of the vegetation, the PyC generated may represent an additional C pool and, hence, recurring fire-regrowth cycles could represent net sinks of atmospheric C. To estimate the quantitative importance of PyC production, accurate data on PyC generation with respect to the fuel combusted are needed. Unfortunately, detailed quantification of fuel prior to fire is normally only available for prescribed and experimental fires, which are usually of low-intensity and therefore not representative of higher-intensity wildfires. Furthermore, what little data is available is usually based on only a specific fraction of the PyC present following burning rather than the whole range of PyC products and pools (i.e. PyC in soil, ash, downed wood and standing vegetation). To address this research gap, we utilized the globally unique FireSmart experimental forest fires in Northwest Canada. They are aimed to reproduce wildfire conditions typical for boreal forest and, at the same time, allow pre-fire fuel assessment, fire behaviour monitoring and immediate post-fire fuel and PyC inventory. This allowed, for the first time, quantifying the whole range of PyC components found in-situ immediately after a typical boreal forest fire. The fire examined had a fireline intensity of ~8000 kw/m, which is typical of boreal fires in NW Canada and we found that more than 18% of the fuel consumed was converted to PyC. This rate by far exceeds previous estimates (1-3%) and suggests that PyC production has indeed been substantially underestimated. As boreal forests are the world's largest terrestrial biome and contain half of the forest ecosystem C with a third its net primary productivity being consumed by fire every year, our findings could imply that PyC production from wildfires is a potential carbon sequestration mechanism of sufficient magnitude that warrants inclusion in boreal and perhaps global C budget estimations.

  18. Carbon dioxide-activated carbons from almond tree pruning: Preparation and characterization

    NASA Astrophysics Data System (ADS)

    Gañán, J.; González, J. F.; González-García, C. M.; Ramiro, A.; Sabio, E.; Román, S.

    2006-06-01

    Activated carbons were prepared from almond tree pruning by non-catalytic and catalytic gasification with carbon dioxide and their surface characteristics were investigated. In both series a two-stage activation procedure (pyrolysis at 800 °C in nitrogen atmosphere, followed by carbon dioxide activation) was used for the production of activated samples. In non-catalytic gasification, the effect of the temperature (650-800 °C for 1 h) and the reaction time (1-12 h at 650 °C) on the surface characteristics of the prepared samples was investigated. Carbons were characterized by means of nitrogen adsorption isotherms at 77 K. The textural parameters of the carbons present a linear relation with the conversion degree until a value of approximately 40%, when they come independent from both parameters studied. The highest surface area obtained for this series was 840 m 2 g -1. In the catalytic gasification the effect of the addition of one catalyst (K and Co) and the gasification time (2-4 h) on the surface and porosity development of the carbons was also studied. At the same conditions, Co leads to higher conversion values than K but this last gives a better porosity development.

  19. Method for production of carbon nanofiber mat or carbon paper

    DOEpatents

    Naskar, Amit K.

    2015-08-04

    Method for the preparation of a non-woven mat or paper made of carbon fibers, the method comprising carbonizing a non-woven mat or paper preform (precursor) comprised of a plurality of bonded sulfonated polyolefin fibers to produce said non-woven mat or paper made of carbon fibers. The preforms and resulting non-woven mat or paper made of carbon fiber, as well as articles and devices containing them, and methods for their use, are also described.

  20. 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.

  1. Biomass-based palm shell activated carbon and palm shell carbon molecular sieve as gas separation adsorbents.

    PubMed

    Sethupathi, Sumathi; Bashir, Mohammed Jk; Akbar, Zinatizadeh Ali; Mohamed, Abdul Rahman

    2015-04-01

    Lignocellulosic biomass has been widely recognised as a potential low-cost source for the production of high added value materials and proved to be a good precursor for the production of activated carbons. One of such valuable biomasses used for the production of activated carbons is palm shell. Palm shell (endocarp) is an abundant by-product produced from the palm oil industries throughout tropical countries. Palm shell activated carbon and palm shell carbon molecular sieve has been widely applied in various environmental pollution control technologies, mainly owing to its high adsorption performance, well-developed porosity and low cost, leading to potential applications in gas-phase separation using adsorption processes. This mini-review represents a comprehensive overview of the palm shell activated carbon and palm shell carbon molecular sieve preparation method, physicochemical properties and feasibility of palm shell activated carbon and palm shell carbon molecular sieve in gas separation processes. Some of the limitations are outlined and suggestions for future improvements are pointed out. PMID:25804669

  2. Natural Product Polyamines That Inhibit Human Carbonic Anhydrases

    PubMed Central

    Davis, Rohan A.; Vullo, Daniela; Supuran, Claudiu T.

    2014-01-01

    Natural product compound collections have proven an effective way to access chemical diversity and recent findings have identified phenolic, coumarin, and polyamine natural products as atypical chemotypes that inhibit carbonic anhydrases (CAs). CA enzymes are implicated as targets of variable drug therapeutic classes and the discovery of selective, drug-like CA inhibitors is essential. Just two natural product polyamines, spermine and spermidine, have until now been investigated as CA inhibitors. In this study, five more complex natural product polyamines 15, derived from either marine sponge or fungi, were considered for inhibition of six different human CA isozymes of interest in therapeutic drug development. All compounds share a simple polyamine core fragment, either spermine or spermidine, yet display substantially different structure activity relationships for CA inhibition. Notably, polyamines 15 were submicromolar inhibitors of the cancer drug target CA IX, this is more potent than either spermine or spermidine. PMID:25162012

  3. 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.

  4. Granular activated carbon: Design, operation and cost

    SciTech Connect

    Clark, R.M.; Lykins, B.W.

    1990-01-01

    A summary is presented of design, cost, and performance information on the application of application of granular activated carbon (GAC) in drinking water based on field-scale experience. A brief history of the development of regulations for control of synthetic organics in drinking water is presented. The use of GAC in other countries is discussed and various design concepts for the unit operations that make up the GAC process are explored. Included in the book are chapters that present information from field-scale research projects dealing with the performance of virgin and reactivated carbon; problems and limitations of carbon reactivation systems; and use of carbon for removing trihalomethanes, trihalomethane precursors, and synthetic organics. The last chapter provides cost equations and comparative cost studies for full-scale application of GAC.

  5. Production and screening of carbon products precursors from coal. Quarterly technical report, October 1, 1996--December 31, 1996

    SciTech Connect

    Irwin, C.L.

    1997-02-01

    The technical work during this past quarter has focused on enhancing equipment and instrumentation in the WVU Carbon Products Laboratory. Development work on coal-based precursors for carbon foams, pitches, cokes, and fibers continues. The effects of carbon powders and chopped fibers as additives to the foam precursor are being evaluated. Extensive coordination and technology transfer activities have been undertaken and are described in Section 5 of this report.

  6. Waste management activities and carbon emissions in Africa

    SciTech Connect

    Couth, R.; Trois, C.

    2011-01-15

    This paper summarizes research into waste management activities and carbon emissions from territories in sub-Saharan Africa with the main objective of quantifying emission reductions (ERs) that can be gained through viable improvements to waste management in Africa. It demonstrates that data on waste and carbon emissions is poor and generally inadequate for prediction models. The paper shows that the amount of waste produced and its composition are linked to national Gross Domestic Product (GDP). Waste production per person is around half that in developed countries with a mean around 230 kg/hd/yr. Sub-Saharan territories produce waste with a biogenic carbon content of around 56% (+/-25%), which is approximately 40% greater than developed countries. This waste is disposed in uncontrolled dumps that produce large amounts of methane gas. Greenhouse gas (GHG) emissions from waste will rise with increasing urbanization and can only be controlled through funding mechanisms from developed countries.

  7. Nitric acid vapor removal by activated, impregnated carbons

    SciTech Connect

    Wood, G.O.

    1996-12-31

    Laboratory and industrial workers can be exposed to vapors of nitric acid, especially in accidents, such as spills. Nitric acid can also be a product of incineration for energy production or waste (e.g., CW agent) disposal. Activated carbons containing impregnants for enhancing vapor and gas removal have been tested for effectiveness in removing vapors of nitric acid from air. The nitric acid vapor was generated from concentrated acid solutions and detected by trapping in a water bubbler for pH measurements. Both low and moderate relative humidity conditions were used. All carbons were effective at vapor contact times representative of air-purifying respirator use. One surprising observation was the desorption of low levels of ammonia from impregnated carbons. This was apparently due to residual ammonia from the impregnation processes.

  8. 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.

  9. Preparation and characterization of activated carbon from demineralized tyre char

    NASA Astrophysics Data System (ADS)

    Manocha, S.; Prasad, Guddu R.; Joshi, Parth.; Zala, Ranjitsingh S.; Gokhale, Siddharth S.; Manocha, L. M.

    2013-06-01

    Activated carbon is the most adsorbing material for industrial waste water treatment. For wider applications, the main consideration is to manufacture activated carbon from low cost precursors, which are easily available and cost effective. One such source is scrap tyres. Recently much effort has been devoted to the thermal degradation of tyres into gaseous and liquid hydrocarbons and solid char residue, all of which have the potential to be processed into valuable products. As for solid residue, char can be used either as low-grade reinforcing filler or as activated carbon. The product recovered by a typical pyrolysis of tyres are usually, 33-38 wt% pyrolytic char, 38-55 wt% oil and 10-30 wt% solid fractions. In the present work activated carbon was prepared from pyrolyzed tyre char (PC). Demineralization involves the dissolution of metal into acids i.e. HCl, HNO3 and H2SO4 and in base i.e. NaOH. Different concentration of acid and base were used. Sodium hydroxide showed maximum amount of metal oxide removal. Further the concentration of sodium hydroxide was varied from 1N to 6N. As the concentration of acid are increased demineralization increases. 6N Sodium hydroxide is found to be more effective demineralising agent of tyre char.

  10. ACTIVATED CARBON TREATMENT OF KRAFT BLEACHING EFFLUENTS

    EPA Science Inventory

    The removal of color and organic contaminants by adsorption on activated carbon from the effluent of a kraft pulp bleaching plant was investigated in a pilot plant. The caustic bleach effluent, which contains 80% of the color from pulp bleaching, was decolorized successfully when...

  11. EPA'S RESEARCH PROGRAM IN GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    Research into Granular Activated Carbon (GAC) for use in drinking water treatment has a long history in the Drinking Water Research Division and its predecessor organizations. tudies were conducted by the U.S. Public Health Service in the late fifties and early sixties to examine...

  12. 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...

  13. Activity of lithium intercalated in carbon materials

    SciTech Connect

    Skundin, A.M.; Egorkina, O.Yu.

    1995-04-01

    The equilibrium potentials of carbonized cloth electrode are measured upon lithium intercalation from LiClO{sub 4} in different solvents. In all cases, the relationship between the activity of lithium intercalated and its concentration is described by the power function, whose exponent depends on the electrolyte nature.

  14. 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...

  15. 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...

  16. 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.

  17. Production of carbon molecular sieves from Illinois coal

    USGS Publications Warehouse

    Lizzio, A.A.; Rostam-Abadi, M.

    1993-01-01

    Carbon molecular sieves (CMS) have become an increasingly important class of adsorbents for application in the separation of gas molecules that vary in size and shape. A study is in progress at the Illinois State Geological Survey to determine whether Illinois basin coals are suitable feedstocks for the production of CMS and to evaluate their potential application in gas separation processes of commercial importance. Chars were prepared from Illinois coal in a fixed-bed reactor under a wide range of heat treatment and activation conditions. The effects of various coal/char pretreatments, including coal demineralization, preoxidation, char activation, and carbon deposition, on the molecular sieve properties of the chars were also investigated. Chars with commercially significant BET surface areas of 1500 m2/g were produced by chemical activation using potassium hydroxide as the activant. These high-surface-area (HSA) chars had more than twice the adsorption capacity of commercial carbon and zeolite molecular sieves. The kinetics of adsorption of various gases, e.g., N2, O2, CO2, CH4, CO and H2, on these chars at 25??C was measured. The O2/N2 molecular sieve properties of one char prepared without chemical activation were similar to those of a commercial CMS. On the other hand, the O2/N2 selectivity of the HSA char was comparable to that of a commercial activated carbon, i.e., essentially unity. Carbon deposition, using methane as the cracking gas, increased the O2/N2 selectivity of the HSA char, but significantly decreased its adsorption capacity. Several chars showed good potential for efficient CO2/CH4 separation; both a relatively high CO2 adsorption capacity and CO2/CH4 selectivity were achieved. The micropore size distribution of selected chars was estimated by equilibrium adsorption of carbon dioxide, n-butane and iso-butane at O??C. The extent of adsorption of each gas corresponded to the effective surface area contained in pores with diameters greater than 3.3, 4.3 and 5.0 A??, respectively. Kinetic and equilibrium adsorption data provided complementary information on the molecular sieving capabilities and microstructure of the prepared chars. ?? 1993.

  18. Improved granular activated carbon for the stabilization of wastewater PH

    SciTech Connect

    Farmer, R.W.; Dussert, B.W.; Kovacic, S.L.

    1996-12-31

    Laboratory studies have identified the cause of the pH rise, which occurs during water treatment with activated carbon, as an interaction between the naturally occurring anions and protons in the water and the carbon surface. The interaction can be described as an ion exchange type of phenomenon, in which the carbon surface sorbs the anions and corresponding hydronium ions from the water. These studies have shown that the anion sorption and resulting pH increase is independent of the raw material used for the activated carbon production, e.g. bituminous or subbituminous coal, peat, wood or coconut. Also, the pH excursions occur with virgin, reactivated, and acid washed granular carbons. Current pH control technologies focus on adjustment of the wastewater pH prior to discharge or recycle of the initial effluent water until the pH increase abates. However, improved water pH control options have been realized by altering the carbon surface through controlled oxidation rather than the water chemistry or extended preprocessing at the treatment site.

  19. Studying the effectiveness of activated carbon R95 respirators in reducing the inhalation of combustion by-products in Hanoi, Vietnam: a demonstration study

    PubMed Central

    2012-01-01

    Background Urban air pollution is an increasing health problem, particularly in Asia, where the combustion of fossil fuels has increased rapidly as a result of industrialization and socio-economic development. The adverse health impacts of urban air pollution are well established, but less is known about effective intervention strategies. In this demonstration study we set out to establish methods to assess whether wearing an R95 activated carbon respirator could reduce intake of polycyclic aromatic hydrocarbons (PAH) in street workers in Hanoi, Vietnam. Methods In this demonstration study we performed a cross-over study in which non-smoking participants that worked at least 4 hours per day on the street in Hanoi were randomly allocated to specific respirator wearing sequences for a duration of 2 weeks. Urines were collected after each period, i.e. twice per week, at the end of the working day to measure hydroxy PAHs (OH-PAH) using gas chromatography/high resolution mass spectrometry. The primary endpoint was the urinary concentration of 1-hydroxypyrene (1-OHP). Results Forty-four participants (54.5% male, median age 40 years) were enrolled with the majority being motorbike taxi drivers (38.6%) or street vendors (34.1%). The baseline creatinine corrected urinary level for 1-OHP was much higher than other international comparisons: 1020 ng/g creatinine (IQR: 6041551). Wearing a R95 mask had no significant effect on 1-OHP levels: estimated multiplicative effect 1.0 (95% CI: 0.92-1.09) or other OH-PAHs, except 1-hydroxynaphthalene (1-OHN): 0.86 (95% CI: 0.11-0.96). Conclusions High levels of urine OH-PAHs were found in Hanoi street workers. No effect was seen on urine OH-PAH levels by wearing R95 particulate respirators in an area of high urban air pollution, except for 1-OHN. A lack of effect may be de to gaseous phase PAHs that were not filtered efficiently by the respirator. The high levels of urinary OH-PAHs found, urges for effective interventions. Trial registration ISRCTN74390617 (date of assignation: 04/08/2009). PMID:23013369

  20. Production of carbon molecular sieves from illinois coals. An assessment

    USGS Publications Warehouse

    Lizzio, Anthony A.; Rostam-Abadi, Massoud

    1991-01-01

    Chars were produced from an Illinois No. 2 bituminous coal under various pyrolysis and activation conditions and tested for their molecular sieve properties. The amount of N2 compared to the amount of CO2 adsorbed by each char was used as a preliminary indicator of its molecular sieve properties. This relatively simple, but apparently useful test was confirmed by successfully characterizing the well-known molecular sieve properties of a commercial zeolite and molecular sieve carbon. In addition, coal chars having relatively high surface areas (800-1800 m2/g) were produced and tested for their molecular sieving capabilities. These carbon materials, which have high adsorption capacities and relatively narrow pore size distributions, should be ideal candidates for the commercial production of CMS.

  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. Activated carbon from vetiver roots: gas and liquid adsorption studies.

    PubMed

    Gaspard, S; Altenor, S; Dawson, E A; Barnes, P A; Ouensanga, A

    2007-06-01

    Large quantities of lignocellulosic residues result from the industrial production of essential oil from vetiver grass (Vetiveria zizanioides) roots. These residues could be used for the production of activated carbon. The yield of char obtained after vetiver roots pyrolysis follows an equation recently developed [A. Ouensanga, L. Largitte, M.A. Arsene, The dependence of char yield on the amounts of components in precursors for pyrolysed tropical fruit stones and seeds, Micropor. Mesopor. Mater. 59 (2003) 85-91]. The N(2) adsorption isotherm follows either the Freundlich law K(F)P(alpha) which is the small alpha equation limit of a Weibull shaped isotherm or the classical BET isotherm. The surface area of the activated carbons are determined using the BET method. The K(F) value is proportional to the BET surface area. The alpha value increases slightly when the burn-off increases and also when there is a clear increase in the micropore distribution width. PMID:17092643

  3. Preparation of activated carbons from macadamia nut shell and coconut shell by air activation

    SciTech Connect

    Tam, M.S.; Antal, M.J. Jr.

    1999-11-01

    A novel, three-step process for the production of high-quality activated carbons from macadamia nut shell and coconut shell charcoals is described. In this process the charcoal is (1) heated to a high temperature (carbonized), (2) oxidized in air following a stepwise heating program from low (ca. 450 K) to high (ca. 660 K) temperatures (oxygenated), and (3) heated again in an inert environment to a high temperature (activated). By use of this procedure, activated carbons with surface areas greater than 1,000 m{sub 2}/g are manufactured with an overall yield of 15% (based on the dry shell feed). Removal of carbon mass by the development of mesopores and macropores is largely responsible for increases in the surface area of the carbons above 600 m{sub 2}/g. Thus, the surface area per gram of activated carbon can be represented by an inverse function of the yield for burnoffs between 15 and 60%. These findings are supported by mass-transfer calculations and pore-size distribution measurements. A kinetic model for gasification of carbon by oxygen, which provides for an Eley-Rideal type reaction of a surface oxide with oxygen in air, fits the measured gasification rates reasonably well over the temperature range of 550--660 K.

  4. Adsorption of methyl orange using activated carbon prepared from lignin by ZnCl2 treatment

    NASA Astrophysics Data System (ADS)

    Mahmoudi, K.; Hamdi, N.; Kriaa, A.; Srasra, E.

    2012-08-01

    Lignocellulosic materials are good and cheap precursors for the production of activated carbon. In this study, activated carbons were prepared from the lignin at different temperatures (200 to 500C) by ZnCl2. The effects influencing the surface area of the resulting activated carbon are activation temperature, activation time and impregnation ratio. The optimum condition, are found an impregnation ratio of 2, an activation temperature of 450C, and an activation time of 2 h. The results showed that the surface area and micropores volume of activated carbon at the experimental conditions are achieved to 587 and 0.23 cm3 g-1, respectively. The adsorption behavior of methyl orange dye from aqueous solution onto activated lignin was investigated as a function of equilibrium time, pH and concentration. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 300 mg g-1 of methyl orange by activated carbon was achieved.

  5. Behavior of glyoxal during granular activated carbon treatment

    SciTech Connect

    Yamamori, H.; Sato, T.; Nagase, H.; Kito, H. ); Matsuda, H. ); Ose, Y. )

    1993-02-01

    Glyoxal, which was the strong mutagen formed by ozonation of humic substances, was treated with granular activated carbon (GAC) and the behavior of glyoxal was investigated. Glyoxal itself was adsorbed well on GAC at pH 5-7. But, glyoxal increased by GAC treatment of ozonated humic substances when the ozone dose was insufficient to decolorize the humic substances. The precursors of glyoxal may be among other ozonated products which may be changed to glyoxal on GAC. 23 refs., 3 figs.

  6. Product carbon footprints and their uncertainties in comparative decision contexts.

    PubMed

    Henriksson, Patrik J G; Heijungs, Reinout; Dao, Hai M; Phan, Lam T; de Snoo, Geert R; Guine, Jeroen B

    2015-01-01

    In response to growing awareness of climate change, requests to establish product carbon footprints have been increasing. Product carbon footprints are life cycle assessments restricted to just one impact category, global warming. Product carbon footprint studies generate life cycle inventory results, listing the environmental emissions of greenhouse gases from a product's lifecycle, and characterize these by their global warming potentials, producing product carbon footprints that are commonly communicated as point values. In the present research we show that the uncertainties surrounding these point values necessitate more sophisticated ways of communicating product carbon footprints, using different sizes of catfish (Pangasius spp.) farms in Vietnam as a case study. As most product carbon footprint studies only have a comparative meaning, we used dependent sampling to produce relative results in order to increase the power for identifying environmentally superior products. We therefore argue that product carbon footprints, supported by quantitative uncertainty estimates, should be used to test hypotheses, rather than to provide point value estimates or plain confidence intervals of products' environmental performance. PMID:25781175

  7. Preparation of functionalized and metal-impregnated activated carbon by a single-step activation method

    NASA Astrophysics Data System (ADS)

    Dastgheib, Seyed A.; Ren, Jianli; Rostam-Abadi, Massoud; Chang, Ramsay

    2014-01-01

    A rapid method to prepare functionalized and metal-impregnated activated carbon from coal is described in this paper. A mixture of ferric chloride and a sub-bituminous coal was used to demonstrate simultaneous coal activation, chlorine functionalization, and iron/iron oxides impregnation in the resulting porous carbon products. The FeCl3 concentration in the mixture, the method to prepare the FeCl3-coal mixture (solid mixing or liquid impregnation), and activation atmosphere and temperature impacted the surface area and porosity development, Cl functionalization, and iron species impregnation and dispersion in the carbon products. Samples activated in nitrogen or a simulated flue gas at 600 or 1000 C for 1-2 min had surface areas up to ?800 m2/g, bulk iron contents up to 18 wt%, and surface chlorine contents up to 27 wt%. Potential catalytic and adsorption application of the carbon materials was explored in catalytic wet air oxidation (CWAO) of phenol and adsorption of ionic mercury from aqueous solutions. Results indicated that impregnated activated carbons outperformed their non-impregnated counterparts in both the CWAO and adsorption tests.

  8. MOLTEN CARBONATE FUEL CELL PRODUCT DESIGN IMPROVEMENT

    SciTech Connect

    H.C. Maru; M. Farooque

    2004-08-01

    The ongoing program is designed to advance the carbonate fuel cell technology from full-size proof-of-concept field test to the commercial design. DOE has been funding Direct FuelCell{reg_sign} (DFC{reg_sign}) development at FuelCell Energy, Inc. (FCE) for stationary power plant applications. The program efforts are focused on technology and system optimization for cost reduction, leading to commercial design development and prototype system field trials. FCE, Danbury, CT, is a world-recognized leader for the development and commercialization of high efficiency fuel cells that can generate clean electricity at power stations, or at distributed locations near the customers such as hospitals, schools, universities, hotels and other commercial and industrial applications. FCE has designed three different fuel cell power plant models (DFC300A, DFC1500 and DFC3000). FCE's power plants are based on its patented DFC{reg_sign} technology, where the fuel is directly fed to the fuel cell and hydrogen is generated internally. These power plants offer significant advantages compared to the existing power generation technologies--higher fuel efficiency, significantly lower emissions, quieter operation, flexible siting and permitting requirements, scalability and potentially lower operating costs. Also, the exhaust heat by-product can be used for cogeneration applications such as high-pressure steam, district heating and air conditioning. Several FCE sub-megawatt power plants are currently operating in Europe, Japan and the US. Because hydrogen is generated directly within the fuel cell module from readily available fuels such as natural gas and waste water treatment gas, DFC power plants are ready today and do not require the creation of a hydrogen infrastructure. Product improvement progress made during the reporting period in the areas of technology, manufacturing processes, cost reduction and balance of plant equipment designs is discussed in this report.

  9. Nitrogen activated-carbon sorption compressor

    NASA Astrophysics Data System (ADS)

    Tzabar, Nir; Grossman, Gershon

    2012-06-01

    Joule-Thomson (JT) sorption cryocooling is the most mature technology for cooling from a normal Room-Temperature (RT) down to temperatures below 100 K in the absence of moving parts. Therefore, high reliability and no vibrations are attainable, in comparison with other cryocoolers. Nitrogen is usually used as the working fluid for cooling to temperatures between 80 and 100 K and activated carbons are the best adsorbent for this purpose. In this paper we present the development of a sorption compressor for nitrogen with a commercial Chemviron pelleted activated carbon. The development consists of sorption measurements that we performed for characterizing the adsorption of nitrogen on the selected adsorbent, and the compressor experimental results are compared with equilibrium condition analysis and numerical heat transfer analysis predictions

  10. PRODUCTION AND SCREENING OF CARBON PRODUCTS PRECURSORS FROM COAL

    SciTech Connect

    Caulton L. Irwin

    2001-05-31

    The authors have examined effects of blending a raw coal extract (EXT) with an extracted coal-tar pitch (ECTP). Previous reports were concerned with the addition of 15 wt% EXT, or less, on the physical characteristics of the blend and on the development of optical texture following carbonization. Two additional blends of ECTP and EXT were prepared at the 30 and 50 wt% EXT content using a procedure already described. The characteristics of the blends are presented. The density for these blended materials is not much different than the density for the blends reported earlier. The softening point temperature for the 30 wt% EXT increased to over 200 C while the softening point temperature for the 50 wt% EXT blend was too high to be determined by the Mettler method. Coke yields approximately follow the law of mixtures. The optical texture of the green cokes for the 30 and 50 wt% EXT blends is shown. Though the optical texture of the green cokes was not significantly affected where the level of EXT is 15 wt% or less, larger proportions of EXT exert a marked reduction in anisotropy. The co-processing of coal with petroleum residues or other heavy hydrocarbons at elevated temperature and pressure has received considerable attention in the research community as a means to upgrade simultaneously coal and byproducts. Heavy hydrocarbons can function as sources of hydrogen, as well as performing as a medium for dissolution and dispersion of coal fragments. However, the focus of much of the prior research has been on developing fuels, distillable liquids, or synthetic crudes. Comparatively little effort has been deliberately directed toward the production of heavier, non-distillable materials which could perform as binder and extender pitches, impregnants, or feedstocks for cokes and other carbons.

  11. Adsorption of chlorophenols on granular activated carbon

    SciTech Connect

    Yang, M.

    1993-12-31

    Studies were undertaken of the adsorption of chlorinated phenols from aqueous solution on granular activated carbon (Filtrasorb-400, 30 x 40 mesh). Single-component equilibrium adsorption data on the eight compounds in two concentration ranges at pH 7.0 fit the Langmuir equation better than the Freundlich equation. The adsorptive capacities at pH 7.0 increase from pentachlorophenol to trichlorophenols and are fairly constant from trichlorophenols to monochlorophenols. The adsorption process was found to be exothermic for pentachlorophenol and 2,4,6-trichlorophenol, and endothermic for 2,4-dichlorophenol and 4-chlorophenol. Equilibrium measurements were also conducted for 2,4,5-trichlorophenol, 2,4-dichlorophenol, and 4-chlorophenol over a wide pH range. A surface complexation model was proposed to describe the effect of pH on adsorption equilibria of chlorophenols on activated carbon. The simulations of the model are in excellent agreement with the experimental data. Batch kinetics studies were conducted of the adsorption of chlorinated phenols on granular activated carbon. The results show that the surface reaction model best describes both the short-term and long-term kinetics, while the external film diffusion model describes the short-term kinetics data very well and the linear-driving-force approximation improved its performance for the long-term kinetics. Multicomponent adsorption equilibria of chlorophenols on granular activated carbon was investigated in the micromolar equilibrium concentration range. The Langmuir competitive and Ideal Adsorbed Solution (IAS) models were tested for their performance on the three binary systems of pentachlorophenol/2,4,6-trichlorophenol, 2,4,6-trichlorophenol/2,4-dichlorophenol, and 2,4-dichlorophenol/4-chlorophenol, and the tertiary system of 2,4,6-trichlorophenol/2,4-dichlorophenol/4-chlorophenol, and found to fail to predict the two-component adsorption equilibria of the former two binary systems and the tertiary system.

  12. Carbon nano structures: Production and characterization

    NASA Astrophysics Data System (ADS)

    Beig Agha, Rosa

    L'objectif de ce memoire est de preparer et de caracteriser des nanostructures de carbone (CNS -- Carbon Nanostructures, en licence a l'Institut de recherche sur l'hydrogene, Quebec, Canada), un carbone avec un plus grand degre de graphitisation et une meilleure porosite. Le Chapitre 1 est une description generale des PEMFCs (PEMFC -- Polymer Electrolyte Membrane Fuel Cell) et plus particulierement des CNS comme support de catalyseurs, leur synthese et purification. Le Chapitre 2 decrit plus en details la methode de synthese et la purification des CNS, la theorie de formation des nanostructures et les differentes techniques de caracterisation que nous avons utilises telles que la diffraction aux rayons-X (XRD -- X-ray diffraction), la microscopie electronique a transmission (TEM -- transmission electron microscope ), la spectroscopie Raman, les isothermes d'adsorption d'azote a 77 K (analyse BET, t-plot, DFT), l'intrusion au mercure, et l'analyse thermogravimetrique (TGA -- thermogravimetric analysis). Le Chapitre 3 presente les resultats obtenus a chaque etape de la synthese des CNS et avec des echantillons produits a l'aide d'un broyeur de type SPEXRTM (SPEX/CertiPrep 8000D) et d'un broyeur de type planetaire (Fritsch Pulverisette 5). La difference essentielle entre ces deux types de broyeur est la facon avec laquelle les materiaux sont broyes. Le broyeur de type SPEX secoue le creuset contenant les materiaux et des billes d'acier selon 3 axes produisant ainsi des impacts de tres grande energie. Le broyeur planetaire quant a lui fait tourner et deplace le creuset contenant les materiaux et des billes d'acier selon 2 axes (plan). Les materiaux sont donc broyes differemment et l'objectif est de voir si les CNS produits ont les memes structures et proprietes. Lors de nos travaux nous avons ete confrontes a un probleme majeur. Nous n'arrivions pas a reproduire les CNS dont la methode de synthese a originellement ete developpee dans les laboratoires de l'Institut de recherche sur l'hydrogene (IRH). Nos echantillons presentaient toujours une grande quantite de carbure de fer au detriment de la formation de nanostructures de carbone. Apres plusieurs mois de recherche nous avons constate que les metaux de base, soit le fer et le cobalt, etaient contamines. Neanmoins, ces recherches nous ont enseigne beaucoup et les resultats sont presentes aux Appendices I a III. Le carbone de depart est du charbon active commercial (CNS201) qui a ete prealablement chauffe a 1,000C sous vide pendant 90 minutes pour se debarrasser de toute humidite et autres impuretes. En premiere etape, dans un creuset d'acier durci du CNS201 pretraite fut melange a une certaine quantite de Fe et de Co (99.9 % purs). Des proportions typiques sont 50 pd. %, 44 pd. %, et 6 pd. % pour le C, le Fe, et le Co respectivement. Pour les echantillons prepares avec le broyeur SPEX, trois a six billes en acier durci furent utilisees pour le broyage, de masse relative echantillon/poudre de 35 a 1. Pour les echantillons prepares avec le broyeur planetaire, trente-six billes en acier durci furent utilisees pour le broyage, de masse relative echantillon/poudre de 10 a 1. L'hydrogene fut alors introduit dans le creuset pour les deux types de broyeur a une pression de 1.4 MPa, et l'echantillon fut broye pendant 12 h pour le SPEX et 24 h pour le planetaire. Le broyeur SPEX a un rendement de transfert d'energie mecanique plus grand qu'un broyeur planetaire, mais il a le desavantage de contaminer davantage l'echantillon en Fe par attrition. Cependant, ceci peut etre neglige vu que le Fe etait un des catalyseurs metalliques ajoutes au creuset. En deuxieme etape, l'echantillon broye est transfere sous gaz inerte (argon) dans un tube en quartz, qui est alors chauffe a 700C pendant 90 minutes. Des mesures de patrons de diffraction a rayons-X sur poudre furent faites pour caracteriser les changements structurels des CNS lors des etapes de synthese. Ces mesures furent prises avec un diffractometre Bruker D8 FOCUS utilisant le rayonnement Cu Ka (lambda = 1.54054 A) et une geometrie Theta/2Theta. La Figure 3.1 montre le patron de diffraction de rayon-X du charbon active utilise comme precurseur pour produire les CNS. Le charbon active est prechauffe a haute temperature (1,000C) pendant 1 h pour enlever l'humidite. La Figure 3.2 montre les patrons de diffraction de rayons-X des echantillons SPEX et planetaire apres broyage de 12 h et 24 h, respectivement. Les structures de charbon ne sont pas encore bien definies, mais un pic a 2theta ? 20-30 correspond aux petites cristallites a caractere turbostatique et un pic correspondant au fer et au carbure de fer apparait a 2theta ? 45. (Abstract shortened by UMI.)

  13. Beneficial Use of Carbon Dioxide in Precast Concrete Production

    SciTech Connect

    Shao, Yixin

    2014-03-31

    The feasibility of using carbon dioxide as feedstock in precast concrete production is studied. Carbon dioxide reacts with calcium compounds in concrete, producing solid calcium carbonates in binding matrix. Two typical precast products are examined for their capacity to store carbon dioxide during the production. They are concrete blocks and fiber‐cement panels. The two products are currently mass produced and cured by steam. Carbon dioxide can be used to replace steam in curing process to accelerate early strength, improve the long‐term durability and reduce energy and emission. For a reaction within a 24‐hour process window, the theoretical maximum possible carbon uptake in concrete is found to be 29% based on cement mass in the product. To reach the maximum uptake, a special process is developed to promote the reaction efficiency to 60‐80% in 4‐hour carbon dioxide curing and improve the resistance to freeze‐thaw cycling and sulfate ion attack. The process is also optimized to meet the project target of $10/tCO{sub 2} in carbon utilization. By the use of self‐concentrating absorption technology, high purity CO{sub 2} can be produced at a price below $40/t. With low cost CO{sub 2} capture and utilization technologies, it is feasible to establish a network for carbon capture and utilization at the vicinity of carbon sources. If all block produces and panel producers in United States could adopt carbon dioxide process in their production in place of steam, carbon utilization in these two markets alone could consume more than 2 Mt CO{sub 2}/year. This capture and utilization process can be extended to more precast products and will continue for years to come.

  14. Nonclassical activation of carbon monoxide by organoactinides

    SciTech Connect

    Marks, T.J.; Manriquez, J.M.; Fagan, P.J.; Day, V.W.; Day, C.S.; Vollmer, S.H.

    1980-01-01

    This article reviews recent results on the carbonylation chemistry of bis(pentamethylcyclopentadienyl) thorium and uranium hydrocarbyl and dialkylamide complexes. Facile migratory insertion of carbon monoxide into metal-carbon and metal-nitrogen bonds is observed. In several cases bihaptoacyl and bihaptocarbamoyl complexes were isolated and characterized by single crystal x-ray diffraction. The great strength of the metal-oxygen bonding in these species is evident in metrical and spectral data, as well as in the reaction chemistry, which is decidedly alkoxycarbene-like. In the case of the bis(pentamethylcyclopentadienyl) actinide dialkyls, the final carbonylation products are C-C coupled cis-1,2-enediolate complexes, while for the corresponding bis(dialkylamides), the products are bis(carbamoyl) species. Both types of compound have been characterized by x-ray diffraction. The carbon monoxide chemistry observed here may be of relevance to mechanistic discussions of catalytic CO reduction, especially that involving actinide oxide or actinide oxide supported catalysts.

  15. 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. PMID:25644627

  16. MOLTEN CARBONATE FUEL CELL PRODUCT DESIGN IMPROVEMENT

    SciTech Connect

    H. C. Maru; M. Farooque

    2003-12-19

    The ongoing program is designed to advance the carbonate fuel cell technology from full-size proof-of-concept field test to the commercial design. DOE has been funding Direct FuelCell{reg_sign} (DFC{reg_sign}) development at FuelCell Energy, Inc. (FCE) for stationary power plant applications. The program efforts are focused on technology and system optimization for cost reduction leading to commercial design development and prototype system field trials. FCE, Danbury, CT, is a world-recognized leader for the development and commercialization of high efficiency fuel cells that can generate clean electricity at power stations or in distributed locations near the customer, including hospitals, schools, universities, hotels and other commercial and industrial applications. FuelCell Energy has designed three different fuel cell power plant models (DFC300, DFC1500 and DFC3000). FCE's power plants are based on its patented Direct FuelCell technology, where the fuel is directly fed to fuel cell and hydrogen is generated internally. These power plants offer significant advantages compared to existing power generation technologies--higher fuel efficiency, significantly lower emissions, quieter operation, flexible siting and permitting requirements, scalability and potentially lower operating costs. Also, the exhaust heat by-product can be used for cogeneration applications such as high-pressure steam, district heating, and air conditioning. Several FCE sub-megawatt power plants are currently operating in Europe, Japan and the US. Because hydrogen is generated directly within the fuel cell module from readily available fuels such as natural gas and waste water treatment gas, DFC power plants are ready today and do not require the creation of a hydrogen infrastructure. Product improvement progress made during the reporting period in the areas of technology, manufacturing processes, cost reduction and balance of plant equipment designs is discussed in this report. FCE's DFC products development has been carried out under a joint public-private effort with DOE being the major contributor. Current funding is primarily under a Cooperative Agreement with DOE.

  17. Sorption of cobalt on activated carbons from aqueous solutions

    SciTech Connect

    Paajanen, A.; Lehto, J.; Santapakka, T.; Morneau, J.P.

    1997-01-01

    The efficiencies of 15 commercially available activated carbons were tested for the separation of trace cobalt ({sup 60}Co) in buffer solutions at pH 5.0, 6.7, and 9.1. On the basis of the results four carbon products, Diahope-006, Eurocarb TN5, Hydraffin DG47, and Norit ROW Supra, were selected for further study. These carbons represented varying (low, medium and high) cobalt removal efficiencies and were prepared of three typical raw materials: peat, coconut shell, or coal. Study was made of the effects on sorption efficiencies of factors of interest in metal/radionuclide-bearing waste effluents. These factors were pH, sodium ions, borate, and citrate.

  18. Activated carbon derived from carbon residue from biomass gasification and its application for dye adsorption: Kinetics, isotherms and thermodynamic studies.

    PubMed

    Maneerung, Thawatchai; Liew, Johan; Dai, Yanjun; Kawi, Sibudjing; Chong, Clive; Wang, Chi-Hwa

    2016-01-01

    In this work, activated carbon (AC) as an effective and low-cost adsorbent was successfully prepared from carbon residue (or char, one of the by-products from woody biomass gasification) via physical activation. The surface area of char was significantly increased from 172.24 to 776.46m(2)/g after steam activation at 900C. The obtained activated carbons were then employed for the adsorption of dye (Rhodamine B) and it was found that activated carbon obtained from steam activation exhibited the highest adsorption capability, which is mainly attributed to the higher surface area and the abundance of hydroxyl (-OH) and carboxyl (-COOH) groups on the activated carbon surface. Moreover, it was also found that the adsorption capability significantly increased under the basic condition, which can be attributed to the increased electrostatic interaction between the deprotonated (negatively charged) activated carbon and dye molecules. Furthermore, the equilibrium data were fitted into different adsorption isotherms and found to fit well with Langmuir model (indicating that dye molecules form monolayer coverage on activated carbon) with a maximum monolayer adsorption capability of 189.83mg/g, whereas the adsorption kinetics followed the pseudo-second-order kinetics. PMID:26512858

  19. APPRAISAL OF POWDERED ACTIVATED CARBON PROCESSES FOR MUNICIPAL WASTEWATER TREATMENT

    EPA Science Inventory

    Powdered activated carbon has been the subject of several developmental efforts directed towards producing improved methods for treating municipal wastewaters. Granular activated carbon has proven itself as an effective means of reducing dissolved organic contaminant levels, but ...

  20. Preparation and Characterizations of Carbon Nanospheres Derived from Activated Carbons and Palm Oil as Anode Materials of Lithium Secondary Batteries.

    PubMed

    Arie, Arenst Andreas; Kristianto, Hans; Susanti, Ratna Frida; Devianto, Hary; Halim, Martin; Lee, Joong Kee

    2015-11-01

    Carbon nanospheres (CNSs) with diameter of around 100 nm were synthesized by pyrolysis technique using activated carbon as Fe-catalyst support and palm oil as carbon precursors with various ratios. Firstly, the Fe catalyst were deposited onto the activated carbon by incipient wetness impregnation method using Fe(NO3)2 x 9H2O as precursors with various content of catalyst (5%, 7% and 10% with respect to the carbon support). The carbon products were characterized by X-ray diffraction, transmission electron microscope, scanning electron microscope, Raman spectroscopy, nitrogen adsorption and X-ray photoelectron spectroscopy. Preliminary electrochemical characteristics of as-synthesized CNSs as anode materials of lithium secondary batteries were conducted using Cyclic Voltammetry to observe the mechanism of Li-ion insertion/extraction during charge-discharge tests. PMID:26726654

  1. Enhancing capacitive deionization performance of electrospun activated carbon nanofibers by coupling with carbon nanotubes.

    PubMed

    Dong, Qiang; Wang, Gang; Wu, Tingting; Peng, Senpei; Qiu, Jieshan

    2015-05-15

    Capacitive deionization (CDI) is an alternative, effective and environmentally friendly technology for desalination of brackish water. The performance of the CDI device is highly determined by the electrode materials. In this paper, a composite of carbon nanotubes (CNTs) embedded in activated carbon nanofiber (ACF) was prepared by a direct co-electrospinning way and subsequent CO2 activation. The introduction of CNTs can greatly improve the conductivity while the CO2-mediated activation can render the final product with high porosity. As such, the hybrid structure can provide an excellent storage space and pathways for ion adsorption and conduction. When evaluated as electrode materials for CDI, the as-prepared CNT/ACF composites with higher electrical conductivity and mesopore ratios exhibited higher electrosorption capacity and good regeneration performance in comparison with the pure ACF. PMID:25595622

  2. Carbonate Precipitation through Microbial Activities in Natural Environment, and Their Potential in Biotechnology: A Review.

    PubMed

    Zhu, Tingting; Dittrich, Maria

    2016-01-01

    Calcium carbonate represents a large portion of carbon reservoir and is used commercially for a variety of applications. Microbial carbonate precipitation, a by-product of microbial activities, plays an important metal coprecipitation and cementation role in natural systems. This natural process occurring in various geological settings can be mimicked and used for a number of biotechnologies, such as metal remediation, carbon sequestration, enhanced oil recovery, and construction restoration. In this study, different metabolic activities leading to calcium carbonate precipitation, their native environment, and potential applications and challenges are reviewed. PMID:26835451

  3. Carbonate Precipitation through Microbial Activities in Natural Environment, and Their Potential in Biotechnology: A Review

    PubMed Central

    Zhu, Tingting; Dittrich, Maria

    2016-01-01

    Calcium carbonate represents a large portion of carbon reservoir and is used commercially for a variety of applications. Microbial carbonate precipitation, a by-product of microbial activities, plays an important metal coprecipitation and cementation role in natural systems. This natural process occurring in various geological settings can be mimicked and used for a number of biotechnologies, such as metal remediation, carbon sequestration, enhanced oil recovery, and construction restoration. In this study, different metabolic activities leading to calcium carbonate precipitation, their native environment, and potential applications and challenges are reviewed. PMID:26835451

  4. Tc-99 Adsorption on Selected Activated Carbons - Batch Testing Results

    SciTech Connect

    Mattigod, Shas V.; Wellman, Dawn M.; Golovich, Elizabeth C.; Cordova, Elsa A.; Smith, Ronald M.

    2010-12-01

    CH2M HILL Plateau Remediation Company (CHPRC) is currently developing a 200-West Area groundwater pump-and-treat system as the remedial action selected under the Comprehensive Environmental Response, Compensation, and Liability Act Record of Decision for Operable Unit (OU) 200-ZP-1. This report documents the results of treatability tests Pacific Northwest National Laboratory researchers conducted to quantify the ability of selected activated carbon products (or carbons) to adsorb technetium-99 (Tc-99) from 200-West Area groundwater. The Tc-99 adsorption performance of seven activated carbons (J177601 Calgon Fitrasorb 400, J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, J177612 Norit GAC830, J177613 Norit GAC830, and J177617 Nucon LW1230) were evaluated using water from well 299-W19-36. Four of the best performing carbons (J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, and J177613 Norit GAC830) were selected for batch isotherm testing. The batch isotherm tests on four of the selected carbons indicated that under lower nitrate concentration conditions (382 mg/L), Kd values ranged from 6,000 to 20,000 mL/g. In comparison. Under higher nitrate (750 mg/L) conditions, there was a measureable decrease in Tc-99 adsorption with Kd values ranging from 3,000 to 7,000 mL/g. The adsorption data fit both the Langmuir and the Freundlich equations. Supplemental tests were conducted using the two carbons that demonstrated the highest adsorption capacity to resolve the issue of the best fit isotherm. These tests indicated that Langmuir isotherms provided the best fit for Tc-99 adsorption under low nitrate concentration conditions. At the design basis concentration of Tc 0.865 µg/L(14,700 pCi/L), the predicted Kd values from using Langmuir isotherm constants were 5,980 mL/g and 6,870 mL/g for for the two carbons. These Kd values did not meet the target Kd value of 9,000 mL/g. Tests conducted to ascertain the effects of changing pH showed that at pH values of 6.5 and 7.5, no significant differences existed in Tc-adsorption performance for three of the carbons, but the fourth carbon performed better at pH 7.5. When the pH was increased to 8.5, a slight decline in performance was observed for all carbons. Tests conducted to ascertain the temperature effect on Tc-99 adsorption indicated that at 21 ºC, 27 ºC, and 32 ºC there were no significant differences in Tc-99 adsorption for three of the carbons. The fourth carbon showed a noticeable decline in Tc-99 adsorption performance with increasing temperature. The presence of volatile organic compounds (VOCs) in the source water did not significantly affect Tc-99 adsorption on either of two carbons tested. Technetium-99 adsorption differed by less than 15% with or without VOCs present in the test water, indicating that Tc-99 adsorption would not be significantly affected if VOCs were removed from the water prior to contact with carbon.

  5. Sustainable production of green feed from carbon dioxide and hydrogen.

    PubMed

    Landau, Miron V; Vidruk, Roxana; Herskowitz, Moti

    2014-03-01

    Carbon dioxide hydrogenation to form hydrocarbons was conducted on two iron-based catalysts, prepared according to procedures described in the literature, and on a new iron spinel catalyst. The CO2 conversion measured in a packed-bed reactor was limited to about 60% because of excessive amounts of water produced in this process. Switching to a system of three packed-bed reactors in series with interim removal of water and condensed hydrocarbons increased CO2 conversion to as much as 89%. The pure spinel catalyst displayed a significantly higher activity and selectivity than those of the other iron catalysts. This process produces a product called green feed, which is similar in composition to the product of a high-temperature, iron-based Fischer–Tropsch process from syngas. The green feed can be readily converted into renewable fuels by well-established technologies. PMID:24678062

  6. Regulation of ROS Production and Vascular Function by Carbon Monoxide

    PubMed Central

    Choi, Yoon Kyung; Por, Elaine D.; Kwon, Young-Guen; Kim, Young-Myeong

    2012-01-01

    Carbon monoxide (CO) is a gaseous molecule produced from heme by heme oxygenase (HO). CO interacts with reduced iron of heme-containing proteins, leading to its involvement in various cellular events via its production of mitochondrial reactive oxygen species (ROS). CO-mediated ROS production initiates intracellular signal events, which regulate the expression of adaptive genes implicated in oxidative stress and functions as signaling molecule for promoting vascular functions, including angiogenesis and mitochondrial biogenesis. Therefore, CO generated either by exogenous delivery or by HO activity can be fundamentally involved in regulating mitochondria-mediated redox cascades for adaptive gene expression and improving blood circulation (i.e., O2 delivery) via neovascularization, leading to the regulation of mitochondrial energy metabolism. This paper will highlight the biological effects of CO on ROS generation and cellular redox changes involved in mitochondrial metabolism and angiogenesis. Moreover, cellular mechanisms by which CO is exploited for disease prevention and therapeutic applications will also be discussed. PMID:22928087

  7. Food security and climate change: On the potential to adapt global crop production by active selection to rising atmospheric carbon dioxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural production is under increasing pressure by global anthropogenic changes, including rising population, diversion of cereals to biofuels, increased protein demands, and climatic extremes. Because of the immediate and dynamic nature of these changes, adaptation measures are urgently need...

  8. Product Carbon Footprints and Their Uncertainties in Comparative Decision Contexts

    PubMed Central

    Dao, Hai M.; Phan, Lam T.; de Snoo, Geert R.

    2015-01-01

    In response to growing awareness of climate change, requests to establish product carbon footprints have been increasing. Product carbon footprints are life cycle assessments restricted to just one impact category, global warming. Product carbon footprint studies generate life cycle inventory results, listing the environmental emissions of greenhouse gases from a product’s lifecycle, and characterize these by their global warming potentials, producing product carbon footprints that are commonly communicated as point values. In the present research we show that the uncertainties surrounding these point values necessitate more sophisticated ways of communicating product carbon footprints, using different sizes of catfish (Pangasius spp.) farms in Vietnam as a case study. As most product carbon footprint studies only have a comparative meaning, we used dependent sampling to produce relative results in order to increase the power for identifying environmentally superior products. We therefore argue that product carbon footprints, supported by quantitative uncertainty estimates, should be used to test hypotheses, rather than to provide point value estimates or plain confidence intervals of products’ environmental performance. PMID:25781175

  9. REACTION OF ACTIVATED CARBON WITH AQUEOUS CHLORINE AND CHLORINE DIOXIDE

    EPA Science Inventory

    The objective of this research was to determine whether aqueous chlorine and chlorine dioxide react with activated carbon, or with compounds adsorbed on activated carbon, to produce compounds that would not form in the absence of activated carbon. The experimental conditions were...

  10. 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.

  11. Production and characterization of carbon structures derived from wood

    NASA Astrophysics Data System (ADS)

    Xie, Xinfeng

    The objective of this research was to produce structural carbon materials from wood, a renewable biomaterial, for advanced material application. A broad range of materials were produced for study including carbonized wood, resin infused carbon composites made from carbonized wood, and carbon nanotubes from wood fibers. The effect of slow heating on the properties of carbonized wood was studied and important carbonized wood properties were found to be produced over a range of heating rates and peak temperatures. Slow heating rates promoted the formation and growth of graphene sheets in turbostratic crystallites, which had a significant influence on the electrical resistivity and Young's modulus of the carbonized wood. A reduction in the rate of heating may be beneficial with respect to carbon properties and the prevention of crack production during the manufacture of large monolithic carbon specimens from wood and wood-based materials. Investigation of selected physical and mechanical properties of resin-infused porous carbon composites made from medium density fiberboard demonstrated that the infused material can be used in specific applications, where high mechanical strength is not required but high dimensional stability at elevated-use temperatures, fire safety, or static dissipation and shielding is required. A unique cyclic heating process has been developed to produce carbon nanotubes directly from wood fibers. Study on the oxidative behavior of carbons derived from cellulose and lignin showed that cellulose carbon ablates faster at a lower temperature in air than lignin carbon when they were prepared at temperatures lower than 500C due to cellulose carbon's lower content of aromatic structures. It is hypothesized that the formation of carbon nanotubes during the cyclic heating process occurred via template synthesis, with the nanochannels formed from the ablation of cellulose fibrils functioning as a template. Evidence of formation of nanochannels has been observed, but the growth mechanism of carbon nanotubes in this specific process must be further explored.

  12. Photorespiration and Carbon Limitation Determine Productivity in Temperate Seagrasses

    PubMed Central

    Buapet, Pimchanok; Rasmusson, Lina M.; Gullstrm, Martin; Bjrk, Mats

    2013-01-01

    The gross primary productivity of two seagrasses, Zostera marina and Ruppia maritima, and one green macroalga, Ulva intestinalis, was assessed in laboratory and field experiments to determine whether the photorespiratory pathway operates at a substantial level in these macrophytes and to what extent it is enhanced by naturally occurring shifts in dissolved inorganic carbon (DIC) and O2 in dense vegetation. To achieve these conditions in laboratory experiments, seawater was incubated with U. intestinalis in light to obtain a range of higher pH and O2 levels and lower DIC levels. Gross photosynthetic O2 evolution was then measured in this pretreated seawater (pH, 7.89.8; high to low DIC:O2 ratio) at both natural and low O2 concentrations (adjusted by N2 bubbling). The presence of photorespiration was indicated by a lower gross O2 evolution rate under natural O2 conditions than when O2 was reduced. In all three macrophytes, gross photosynthetic rates were negatively affected by higher pH and lower DIC. However, while both seagrasses exhibited significant photorespiratory activity at increasing pH values, the macroalga U. intestinalis exhibited no such activity. Rates of seagrass photosynthesis were then assessed in seawater collected from the natural habitats (i.e., shallow bays characterized by high macrophyte cover and by low DIC and high pH during daytime) and compared with open baymouth water conditions (where seawater DIC is in equilibrium with air, normal DIC, and pH). The gross photosynthetic rates of both seagrasses were significantly higher when incubated in the baymouth water, indicating that these grasses can be significantly carbon limited in shallow bays. Photorespiration was also detected in both seagrasses under shallow bay water conditions. Our findings indicate that natural carbon limitations caused by high community photosynthesis can enhance photorespiration and cause a significant decline in seagrass primary production in shallow waters. PMID:24376754

  13. Photorespiration and carbon limitation determine productivity in temperate seagrasses.

    PubMed

    Buapet, Pimchanok; Rasmusson, Lina M; Gullstrm, Martin; Bjrk, Mats

    2013-01-01

    The gross primary productivity of two seagrasses, Zostera marina and Ruppia maritima, and one green macroalga, Ulva intestinalis, was assessed in laboratory and field experiments to determine whether the photorespiratory pathway operates at a substantial level in these macrophytes and to what extent it is enhanced by naturally occurring shifts in dissolved inorganic carbon (DIC) and O2 in dense vegetation. To achieve these conditions in laboratory experiments, seawater was incubated with U. intestinalis in light to obtain a range of higher pH and O2 levels and lower DIC levels. Gross photosynthetic O2 evolution was then measured in this pretreated seawater (pH, 7.8-9.8; high to low DIC:O2 ratio) at both natural and low O2 concentrations (adjusted by N2 bubbling). The presence of photorespiration was indicated by a lower gross O2 evolution rate under natural O2 conditions than when O2 was reduced. In all three macrophytes, gross photosynthetic rates were negatively affected by higher pH and lower DIC. However, while both seagrasses exhibited significant photorespiratory activity at increasing pH values, the macroalga U. intestinalis exhibited no such activity. Rates of seagrass photosynthesis were then assessed in seawater collected from the natural habitats (i.e., shallow bays characterized by high macrophyte cover and by low DIC and high pH during daytime) and compared with open baymouth water conditions (where seawater DIC is in equilibrium with air, normal DIC, and pH). The gross photosynthetic rates of both seagrasses were significantly higher when incubated in the baymouth water, indicating that these grasses can be significantly carbon limited in shallow bays. Photorespiration was also detected in both seagrasses under shallow bay water conditions. Our findings indicate that natural carbon limitations caused by high community photosynthesis can enhance photorespiration and cause a significant decline in seagrass primary production in shallow waters. PMID:24376754

  14. MOLTEN CARBONATE FUEL CELL PRODUCT DESIGN IMPROVEMENT

    SciTech Connect

    H.C. Maru; M. Farooque

    2005-03-01

    The program was designed to advance the carbonate fuel cell technology from full-size proof-of-concept field test to the commercial design. DOE has been funding Direct FuelCell{reg_sign} (DFC{reg_sign}) development at FuelCell Energy, Inc. (FCE, formerly Energy Research Corporation) from an early state of development for stationary power plant applications. The current program efforts were focused on technology and system development, and cost reduction, leading to commercial design development and prototype system field trials. FCE, in Danbury, CT, is a world-recognized leader for the development and commercialization of high efficiency fuel cells that can generate clean electricity at power stations, or at distributed locations near the customers such as hospitals, schools, universities, hotels and other commercial and industrial applications. FCE has designed three different fuel cell power plant models (DFC300A, DFC1500 and DFC3000). FCE's power plants are based on its patented DFC{reg_sign} technology, where a hydrocarbon fuel is directly fed to the fuel cell and hydrogen is generated internally. These power plants offer significant advantages compared to the existing power generation technologies--higher fuel efficiency, significantly lower emissions, quieter operation, flexible siting and permitting requirements, scalability and potentially lower operating costs. Also, the exhaust heat by-product can be used for cogeneration applications such as high-pressure steam, district heating and air conditioning. Several sub-MW power plants based on the DFC design are currently operating in Europe, Japan and the US. Several one-megawatt power plant design was verified by operation on natural gas at FCE. This plant is currently installed at a customer site in King County, WA under another US government program and is currently in operation. Because hydrogen is generated directly within the fuel cell module from readily available fuels such as natural gas and waste water treatment gas, DFC power plants are ready today and do not require the creation of a hydrogen infrastructure. Product improvement progress made during the program period in the areas of technology, manufacturing processes, cost reduction and balance-of-plant equipment designs is discussed in this report.

  15. Hierarchically structured activated carbon for ultracapacitors

    NASA Astrophysics Data System (ADS)

    Kim, Mok-Hwa; Kim, Kwang-Bum; Park, Sun-Min; Roh, Kwang Chul

    2016-02-01

    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.

  16. 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

  17. Hierarchically structured activated carbon for ultracapacitors.

    PubMed

    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 m(2) 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

  18. Rhodamine B removal with activated carbons obtained from lignocellulosic waste.

    PubMed

    da Silva Lacerda, Viviane; Lpez-Sotelo, Juan B; Correa-Guimares, Adriana; Hernndez-Navarro, Salvador; Snchez-Bscones, Mercedes; Navas-Gracia, Luis M; Martn-Ramos, Pablo; Martn-Gil, Jess

    2015-05-15

    By-products from the wax production process from carnauba palm (leaves), from the extraction of oil from macauba seeds (endocarp) and from pine nut production (shell) have been assessed for activated carbon production, using H3PO4 or CaCl2 for their chemical activation. The resulting activated charcoals have been thoroughly characterized by elemental and thermal analysis, X-ray diffraction, infrared spectroscopy, electron scanning microscopy and N2 adsorption behavior. Subsequently, their adsorption capacity for the removal of rhodamine B (RhB) from aqueous solutions has been evaluated by studying different parameters: contact time, pH, adsorbent dose, initial dye concentration and solution temperature. The adsorption of RhB followed Freundlich's model in all cases. Kinetic studies indicate that the pseudo-second order model can be used for describing the dynamics of the adsorption process. Thermodynamic parameters have also been evaluated, indicating its endothermic and spontaneous nature. Finally, a preliminary analysis of the impact of cellulose content in the carbon precursor materials has been conducted, by using a mixture of native cellulose with one of the lignocellulosic materials. PMID:25770964

  19. Granular activated carbon and biological activated carbon treatment of dissolved and sorbed polychlorinated biphenyls

    SciTech Connect

    Ghosh, U.; Weber, A.S.; Jensen, J.N.; Smith, J.R.

    1999-03-01

    The most widely practiced treatment method for polychlorinated biphenyls (PCBs) in aqueous wastes is activated carbon adsorption. However, the presence of particulates in aqueous wastes may affect treatment processes primarily designed to treat dissolved. PCBs because PCBs tend to partition strongly to solid surfaces. In this research, bench-scale studies were conducted to investigate the performance of granular activated carbon (GAC) and biological activated carbon (BAC) processes for treating aqueous wastes containing dissolved and sorbed PCBs. When all influent PCBs were dissolved, influent PCBs of approximately 175 {micro}g/L were removed to approximately 0.2 {micro}g/L in the BAC column, compared to approximately 0.8 {micro}g/L in the GAC column. A reduction in the extent of PCB removal was observed for both GAC and BAC processes when 10 mg/L of 0.5-{micro}m polystyrene particles were added to the influent. In the presence of influent particulates, PCB removal was significantly better in the BAC column and equaled 99% compared to 62% in the GAC column. Performance differences between the GAC and BAC columns were attributed to higher particulate capture efficiency of the biological film covering the activated carbon in the BAC column. Biological activated carbon columns thus seem to offer advantages to conventional GAC processes for aqueous wastes containing either dissolved or sorbed PCBs.

  20. Molten carbonate fuel cell product development test

    NASA Astrophysics Data System (ADS)

    1993-12-01

    Advanced fuel cell active components have been developed and scaled up from laboratory scale to commercial scale. Full width components of both the stabilized nickel cathodes and the low chrome anodes have been successfully cast on M-C Power's production tape caster. An improved design for a fuel cell separator plate has been developed. The improved design meets the goals of lower cost and manufacturing simplicity, and addresses performance issues of the current commercial area plate. The engineering that the Bechtel Corporation has completed for the MCFC power plant includes a site design, a preliminary site layout, a Process Flow Diagram, and specification for the procurement of some of the major equipment items. Raw materials for anode and cathode components were ordered and received during the first half of 1993. Tape casting of anodes was started in late summer and continued through August. In addition to the technical progress mentioned above, an environment assessment was prepared in compliance with the National Environmental Policy Act of 1969 (NEPA). As a result, the PDT has received a categorical exclusion from the Air Pollution Control District permit requirements. The PDT is configured to demonstrate the viability of natural gas-fueled MCFC for the production of electricity and thermal energy in an environmentally benign manner for use in commercial and industrial applications.

  1. MOLTEN CARBONATE FUEL CELL PRODUCT DESIGN IMPROVEMENT

    SciTech Connect

    H.C. Maru; M. Farooque

    2002-02-01

    The carbonate fuel cell promises highly efficient, cost-effective and environmentally superior power generation from pipeline natural gas, coal gas, biogas, and other gaseous and liquid fuels. FuelCell Energy, Inc. has been engaged in the development of this unique technology, focusing on the development of the Direct Fuel Cell (DFC{reg_sign}). The DFC{reg_sign} design incorporates the unique internal reforming feature which allows utilization of a hydrocarbon fuel directly in the fuel cell without requiring any external reforming reactor and associated heat exchange equipment. This approach upgrades waste heat to chemical energy and thereby contributes to a higher overall conversion efficiency of fuel energy to electricity with low levels of environmental emissions. Among the internal reforming options, FuelCell Energy has selected the Indirect Internal Reforming (IIR)--Direct Internal Reforming (DIR) combination as its baseline design. The IIR-DIR combination allows reforming control (and thus cooling) over the entire cell area. This results in uniform cell temperature. In the IIR-DIR stack, a reforming unit (RU) is placed in between a group of fuel cells. The hydrocarbon fuel is first fed into the RU where it is reformed partially to hydrogen and carbon monoxide fuel using heat produced by the fuel cell electrochemical reactions. The reformed gases are then fed to the DIR chamber, where the residual fuel is reformed simultaneously with the electrochemical fuel cell reactions. FuelCell Energy plans to offer commercial DFC power plants in various sizes, focusing on the subMW as well as the MW-scale units. The plan is to offer standardized, packaged DFC power plants operating on natural gas or other hydrocarbon-containing fuels for commercial sale. The power plant design will include a diesel fuel processing option to allow dual fuel applications. These power plants, which can be shop-fabricated and sited near the user, are ideally suited for distributed power generation, industrial cogeneration, marine applications and uninterrupted power for military bases. FuelCell Energy operated a 1.8 MW plant at a utility site in 1996-97, the largest fuel cell power plant ever operated in North America. This proof-of-concept power plant demonstrated high efficiency, low emissions, reactive power control, and unattended operation capabilities. Drawing on the manufacture, field test, and post-test experience of the full-size power plant; FuelCell Energy launched the Product Design Improvement (PDI) program sponsored by government and the private-sector cost-share. The PDI efforts are focused on technology and system optimization for cost reduction, commercial design development, and prototype system field trials. The program was initiated in December 1994. Year 2000 program accomplishments are discussed in this report.

  2. Coal precursors for production of carbon and graphite products. Final report

    SciTech Connect

    Lewis, I.C.; Lewis, R.T.; Mayer, H.K.

    1996-04-08

    The main goal of this program was to demonstrate the utility of coal extracts from the West Virginia University (WVU) extraction process as suitable base raw materials for the carbon products encompassed by the Carbon Products Consortium (CPC) team. These include binder and impregnation pitches, Coke for graphite electrodes, Cokes for anodes and specialty graphite, matrices for C/C composites and raw material for mesophase pitch fibers. Previous work in this program has shown that the WVU coal extraction process coupled with hydrotreatment, does have the potential for achieving this objective. The current effort involved screening and evaluation of extracts produced by the WVU Group and recommending appropriate materials for scaleup for subsequent evaluation by Consortium Team members. The program involved an initial characterization of small-scale extracts using standard analytical methods and mesophase formation studies. This was followed by feedback to the WVU Group and to the CPC partners with recommendation of material for scaleup. Similar analytical and mesophase studies on some of the scaled-up extracts was performed. The activation of the coal extraction residues for the purpose of producing a useful active carbon was investigated. A further task was to fabricate a small graphite artifact using Coke derived from coal extract as the filler and the coal extract itself as a binder. The results of the studies are summarized in this report.

  3. Vibration damping with active carbon fiber structures

    NASA Astrophysics Data System (ADS)

    Neugebauer, Reimund; Kunze, Holger; Riedel, Mathias; Roscher, Hans-Jrgen

    2007-04-01

    This paper presents a mechatronic strategy for active reduction of vibrations on machine tool struts or car shafts. The active structure is built from a carbon fiber composite with embedded piezofiber actuators that are composed of piezopatches based on the Macro Fiber Composite (MFC) technology, licensed by NASA and produced by Smart Material GmbH in Dresden, Germany. The structure of these actuators allows separate or selectively combined bending and torsion, meaning that both bending and torsion vibrations can be actively absorbed. Initial simulation work was done with a finite element model (ANSYS). This paper describes how state space models are generated out of a structure based on the finite element model and how controller codes are integrated into finite element models for transient analysis and the model-based control design. Finally, it showcases initial experimental findings and provides an outlook for damping multi-mode resonances with a parallel combination of resonant controllers.

  4. 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.

  5. High surface area active carbon from coal

    SciTech Connect

    Yan Zhenming; Wen Lixian; Wang Yulan; Wang Junjie; Ding Jieran

    1997-12-31

    Recently, more and more attention has been paid to environment problems. Active carbon (AC) has been developed rapidly due to its good adsorption properties. Now, various kinds of AC with different pore structure and chemical property could be made according to the requirements of industrial applications. In America, high surface area active carbon (HSAC) has been made from petroleum coke and coal. It has also been commercialized in Japan by Kansai Coke and Chemicals Company from petroleum coke named Maxsorb. This kind of AC possesses high surface area (above 3,000 m{sup 2}/g) and excellent adsorption capacity. So, it could be used in a high performance adsorption system as well as in conventional situations. For example, it could be used for a high efficient capacitor, high capacity fuel battery and adsorption/separation of CH{sub 4}. However, HSAC from coal hasn`t been well studied in China. In this paper, using coal as raw material and KOH as activating agent, HSAC with surface area in excess of 3,000 m{sup 2}/g was made. The pore width of this AC were in the micropore range with concentrated distribution. It has also low ash content.

  6. 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.

  7. Qualitative determination of carbon black in food products.

    PubMed

    Miranda-Bermudez, E; Belai, N; Harp, B Petigara; Yakes, B J; Barrows, J N

    2012-01-01

    Carbon black (C.I. 77266) is an insoluble pigment produced by the partial combustion of hydrocarbons. The pigment is known by several synonyms, including vegetable carbon, lamp black and carbon ash, that correspond to the raw materials and methods used for its production. Vegetable carbon (E153) is permitted for use in colouring food in the European Union. The US Food and Drug Administration (USFDA) has not approved the use of any type of carbon black for colouring food, although the agency batch certifies the pigment as D&C Black No. 2 for use in colouring certain cosmetics. Since carbon black (as vegetable carbon) may be present in food products offered for import into the United States, the USFDA's district laboratories need a qualitative analytical method for determining its presence. We have developed an extraction method for this purpose. A sample is broken down and dissolved with nitric acid. The resulting solution is filtered and treated with hydrochloric acid to dissolve any black iron oxide also present as a colour additive. A black residue remaining on the filter paper indicates the presence of carbon black in the food. We confirmed the presence of carbon black in residues from several standards and food products using Raman spectroscopy. The limit of detection for this method is 0.0001%. PMID:22035229

  8. Carbonate thermochemical cycle for the production of hydrogen

    DOEpatents

    Collins, Jack L (Knoxville, TN) [Knoxville, TN; Dole, Leslie R (Knoxville, TN) [Knoxville, TN; Ferrada, Juan J (Knoxville, TN) [Knoxville, TN; Forsberg, Charles W (Oak Ridge, TN) [Oak Ridge, TN; Haire, Marvin J (Oak Ridge, TN) [Oak Ridge, TN; Hunt, Rodney D (Oak Ridge, TN) [Oak Ridge, TN; Lewis Jr., Benjamin E (Knoxville, TN) [Knoxville, TN; Wymer, Raymond G (Oak Ridge, TN) [Oak Ridge, TN

    2010-02-23

    The present invention is directed to a thermochemical method for the production of hydrogen from water. The method includes reacting a multi-valent metal oxide, water and a carbonate to produce an alkali metal-multi-valent metal oxide compound, carbon dioxide, and hydrogen.

  9. Carbonate Thermochemical Cycle for the Production of Hydrogen

    SciTech Connect

    Ferrada, Juan J; Collins, Jack Lee; Dole, Leslie Robert; Forsberg, Charles W; Haire, Marvin Jonathan; Hunt, Rodney Dale; Lewis Jr, Benjamin E; Wymer, Raymond; Ladd-Lively, Jennifer L

    2009-01-01

    The present invention is directed to a thermochemical method for the production of hydrogen from water. The method includes reacting a multi-valent metal oxide, water and a carbonate to produce an alkali metal-multi-valent metal oxide compound, carbon dioxide, and hydrogen.

  10. Ultrahigh surface area carbon from carbonated beverages. Combining self-templaing process and in situ activation

    SciTech Connect

    Zhang, Pengfei; Zhang, Zhiyong; Chen, Jihua; Dai, Sheng

    2015-05-11

    Ultrahigh surface area carbons (USACs, e.g., >2000 m2/g) are attracting tremendous attention due to their outstanding performance in energy-related applications. The state-of-art approaches to USACs involve templating or activation methods and all these techniques show certain drawbacks. In this work, a series of USACs with specific surface areas up to 3633 m2/g were prepared in two steps: hydrothermal carbonization (200 °C) of carbonated beverages (CBs) and further thermal treatment in nitrogen (600–1000 °C). The rich inner porosity is formed by a self-templated process during which acids and polyelectrolyte sodium salts in the beverage formulas make some contribution. This strategy covers various CBs such as Coca Cola®, Pepsi Cola®, Dr. Pepper®, andFanta® and it enables an acceptable product yield (based on sugars), for example: 21 wt% for carbon (2940 m2/g) from Coca Cola®. Being potential electrode materials for supercapacitors, those carbon materials possessed a good specific capacitance (57.2–185.7 F g-1) even at a scan rate of 1000 mV s-1. Thus, a simple and efficient strategy to USACs has been presented.

  11. Ultrahigh surface area carbon from carbonated beverages. Combining self-templaing process and in situ activation

    DOE PAGESBeta

    Zhang, Pengfei; Zhang, Zhiyong; Chen, Jihua; Dai, Sheng

    2015-05-11

    Ultrahigh surface area carbons (USACs, e.g., >2000 m2/g) are attracting tremendous attention due to their outstanding performance in energy-related applications. The state-of-art approaches to USACs involve templating or activation methods and all these techniques show certain drawbacks. In this work, a series of USACs with specific surface areas up to 3633 m2/g were prepared in two steps: hydrothermal carbonization (200 °C) of carbonated beverages (CBs) and further thermal treatment in nitrogen (600–1000 °C). The rich inner porosity is formed by a self-templated process during which acids and polyelectrolyte sodium salts in the beverage formulas make some contribution. This strategy coversmore » various CBs such as Coca Cola®, Pepsi Cola®, Dr. Pepper®, andFanta® and it enables an acceptable product yield (based on sugars), for example: 21 wt% for carbon (2940 m2/g) from Coca Cola®. Being potential electrode materials for supercapacitors, those carbon materials possessed a good specific capacitance (57.2–185.7 F g-1) even at a scan rate of 1000 mV s-1. Thus, a simple and efficient strategy to USACs has been presented.« less

  12. 40 CFR 415.450 - Applicability; description of the lithium carbonate production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... lithium carbonate production subcategory. 415.450 Section 415.450 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Lithium Carbonate Production Subcategory 415.450 Applicability; description of the lithium carbonate production subcategory. The provisions of this subpart are applicable to...

  13. 40 CFR 415.450 - Applicability; description of the lithium carbonate production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... lithium carbonate production subcategory. 415.450 Section 415.450 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Lithium Carbonate Production Subcategory 415.450 Applicability; description of the lithium carbonate production subcategory. The provisions of this subpart are applicable to...

  14. Carbon production and export from Biscayne Bay, Florida. II. Episodic export of organic carbon

    NASA Astrophysics Data System (ADS)

    Incze, Michael L.; Roman, M. R.

    1983-07-01

    Seasonal meteorological events of high wind energy are important in the export of organic carbon from Biscayne Bay, Florida, by altering circulation and tidal flushing patterns coincident with increased resuspension. The accumulation of detrital organic carbon in the bay during productive summer months with light south-east breezes is reversed by the onset of the winter season and associated weekly cold fronts with sustained 15 knot northerly winds. The reversal of Biscayne Bay circulation patterns and increased discharge at Caesar's Creek result in an outwelling of dissolved organic carbon and particulate organic carbon. Southward advection at the seaward extremes of exchange channels prevents reintroduction of exported organic carbon by tidal currents.

  15. Accounting for forest carbon pool dynamics in product carbon footprints: Challenges and opportunities

    SciTech Connect

    Newell, Joshua P.; Vos, Robert O.

    2012-11-15

    Modification and loss of forests due to natural and anthropogenic disturbance contribute an estimated 20% of annual greenhouse gas (GHG) emissions worldwide. Although forest carbon pool modeling rarely suggests a 'carbon neutral' flux profile, the life cycle assessment community and associated product carbon footprint protocols have struggled to account for the GHG emissions associated with forestry, specifically, and land use generally. Principally, this is due to underdeveloped linkages between life cycle inventory (LCI) modeling for wood and forest carbon modeling for a full range of forest types and harvest practices, as well as a lack of transparency in globalized forest supply chains. In this paper, through a comparative study of U.S. and Chinese coated freesheet paper, we develop the initial foundations for a methodology that rescales IPCC methods from the national to the product level, with reference to the approaches in three international product carbon footprint protocols. Due to differences in geographic origin of the wood fiber, the results for two scenarios are highly divergent. This suggests that both wood LCI models and the protocols need further development to capture the range of spatial and temporal dimensions for supply chains (and the associated land use change and modification) for specific product systems. The paper concludes by outlining opportunities to measure and reduce uncertainty in accounting for net emissions of biogenic carbon from forestland, where timber is harvested for consumer products. - Highlights: Black-Right-Pointing-Pointer Typical life cycle assessment practice for consumer products often excludes significant land use change emissions when estimating carbon footprints. Black-Right-Pointing-Pointer The article provides a methodology to rescale IPCC guidelines for product-level carbon footprints. Black-Right-Pointing-Pointer Life cycle inventories and product carbon footprint protocols need more comprehensive land use-related accounting. Black-Right-Pointing-Pointer Interdisciplinary collaboration linking the LCA and forest carbon modeling communities is necessary.

  16. 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...

  17. The regeneration of polluted activated carbon by radiation techniques

    NASA Astrophysics Data System (ADS)

    Minghong, Wu; Borong, Bao; Ruimin, Zhou; Jinliang, Zhu; Longxin, Hu

    1998-10-01

    In this paper, the regeneration of used activated carbon from monosodium glutamate factory was experimented using radiation and acid-alkali chemical cleaning method. Results showed that the activated carbon saturated with pollutants can be wash away easily by flushing with chemical solution prior irradiation. DSC was used to monitor the change of carbon adsorption

  18. 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.

  19. Activation and Micropore Structure Determination of Activated Carbon-Fiber Composites

    SciTech Connect

    Jagtoyen, M.; Derbyshire, F.

    1999-04-23

    Previous work focused on the production of carbon fiber composites and subsequently activating them to induce adsorbent properties. One problem related to this approach is the difficulty of uniformly activating large composites. In order to overcome this problem, composites have been made from pre-activated fibers. The loss of surface area upon forming the composites after activation of the fibers was investigated. The electrical resistivity and strength of these composites were compared to those made by activation after forming. It was found that the surface area is reduced by about 35% by forming the composite from pre-activated fibers. However, the properties of the activated sample are very uniform: the variation in surface area is less than {+-}0.5%. So, although the surface area is somewhat reduced, it is believed that making composites from pre-activated fibers could be useful in applications where the BET surface area is not required to be very high. The strength of the composites produced from pre-activated fibers is lower than for composites activated after forming when the carbon burnoff is below 45%. For higher burnoffs, the strength of composites made with pre-activated fibers is as good or better. In both cases, there is a dramatic decrease in strength when the fiber:binder ratio is reduced below 4:1. The electrical resistivity is slightly higher for composites made from pre-activated fibers than for composites that are activated after forming, other parameters being constant (P-200 fibers, similar carbon burnoffs). For both types of composite the resistivity was also found to increase with carbon burnoff. This is attributed to breakage of the fiber causing shorter conductive paths. The electrical resistivity also increases when the binder content is lowered, which suggests that there are fewer solid contact points between the fibers.

  20. Investigations about the quantitative changes of carbon dioxide production in humans. Report 2: Carbon dioxide production during fever and its relationship with heat production

    NASA Technical Reports Server (NTRS)

    Liebermeister, C.

    1978-01-01

    Investigations are cited and explained for carbon dioxide production during fever and its relationship with heat production. The general topics of discussion are: (1) carbon dioxide production for alternating fever attacks; (2) heat balance during the perspiration phase; (3) heat balance during the chill phase; (4) the theory of fever; and (5) chill phase for other fever attacks.

  1. Preparation of activated carbons from bituminous coal pitches

    NASA Astrophysics Data System (ADS)

    Gaan, J.; Gonzlez-Garca, C. M.; Gonzlez, J. F.; Sabio, E.; Macas-Garca, A.; Daz-Dez, 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.

  2. 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-Vzquez, Perla G; Malik, Ashish A; Roy, Jacques; Scheu, Stefan; Steinbeiss, Sibylle; Thomson, Bruce C; Trumbore, Susan E; Gleixner, Gerd

    2015-01-01

    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. PMID:25848862

  3. CRADA Carbon Sequestration in Soils and Commercial Products

    SciTech Connect

    Jacobs, G.K.

    2002-01-31

    ORNL, through The Consortium for Research on Enhancing Carbon Sequestration in Terrestrial Ecosystems (CSiTE), collaborated with The Village Botanica, Inc. (VB) on a project investigating carbon sequestration in soils and commercial products from a new sustainable crop developed from perennial Hibiscus spp. Over 500 pre-treated samples were analyzed for soil carbon content. ORNL helped design a sampling scheme for soils during the planting phase of the project. Samples were collected and prepared by VB and analyzed for carbon content by ORNL. The project did not progress to a Phase II proposal because VB declined to prepare the required proposal.

  4. 40 CFR 415.330 - Applicability; description of the carbon monoxide and by-product hydrogen production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... carbon monoxide and by-product hydrogen production subcategory. 415.330 Section 415.330 Protection of... MANUFACTURING POINT SOURCE CATEGORY Carbon Monoxide and By-Product Hydrogen Production Subcategory § 415.330 Applicability; description of the carbon monoxide and by-product hydrogen production subcategory. The...

  5. 40 CFR 415.330 - Applicability; description of the carbon monoxide and by-product hydrogen production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... carbon monoxide and by-product hydrogen production subcategory. 415.330 Section 415.330 Protection of... MANUFACTURING POINT SOURCE CATEGORY Carbon Monoxide and By-Product Hydrogen Production Subcategory § 415.330 Applicability; description of the carbon monoxide and by-product hydrogen production subcategory. The...

  6. 40 CFR 415.330 - Applicability; description of the carbon monoxide and by-product hydrogen production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... carbon monoxide and by-product hydrogen production subcategory. 415.330 Section 415.330 Protection of... MANUFACTURING POINT SOURCE CATEGORY Carbon Monoxide and By-Product Hydrogen Production Subcategory § 415.330 Applicability; description of the carbon monoxide and by-product hydrogen production subcategory. The...

  7. 40 CFR 415.330 - Applicability; description of the carbon monoxide and by-product hydrogen production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... carbon monoxide and by-product hydrogen production subcategory. 415.330 Section 415.330 Protection of... MANUFACTURING POINT SOURCE CATEGORY Carbon Monoxide and By-Product Hydrogen Production Subcategory § 415.330 Applicability; description of the carbon monoxide and by-product hydrogen production subcategory. The...

  8. 40 CFR 415.330 - Applicability; description of the carbon monoxide and by-product hydrogen production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... carbon monoxide and by-product hydrogen production subcategory. 415.330 Section 415.330 Protection of... MANUFACTURING POINT SOURCE CATEGORY Carbon Monoxide and By-Product Hydrogen Production Subcategory § 415.330 Applicability; description of the carbon monoxide and by-product hydrogen production subcategory. The...

  9. 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...

  10. Carbon Fiber Production from a Kraft Hardwood Lignin

    SciTech Connect

    Baker, Darren A; Gallego, Nidia C; Baker, Frederick S

    2008-01-01

    Lignin is a renewable resource material that is being evaluated for the low cost production of carbon fiber for automotive and other applications. Solvent extraction of a commercial hardwood lignin product yielded a purified lignin free of the contaminants typical of lignins derived from the Kraft chemical pulping of wood. The purified lignin was highly melt-spinnable into fibers, from which carbon fiber was subsequently produced. The lignin has been evaluated in terms of its rheological properties, fiber melt spinning ability, and potential for manufacture of low cost carbon fiber without the need for plasticizing agents or chemical modifications.

  11. Future productivity and carbon storage limited by terrestrial nutrient availability

    NASA Astrophysics Data System (ADS)

    Wieder, William R.; Cleveland, Cory C.; Smith, W. Kolby; Todd-Brown, Katherine

    2015-06-01

    The size of the terrestrial sink remains uncertain. This uncertainty presents a challenge for projecting future climate-carbon cycle feedbacks. Terrestrial carbon storage is dependent on the availability of nitrogen for plant growth, and nitrogen limitation is increasingly included in global models. Widespread phosphorus limitation in terrestrial ecosystems may also strongly regulate the global carbon cycle, but explicit considerations of phosphorus limitation in global models are uncommon. Here we use global state-of-the-art coupled carbon-climate model projections of terrestrial net primary productivity and carbon storage from 1860-2100 estimates of annual new nutrient inputs from deposition, nitrogen fixation, and weathering; and estimates of carbon allocation and stoichiometry to evaluate how simulated CO2 fertilization effects could be constrained by nutrient availability. We find that the nutrients required for the projected increases in net primary productivity greatly exceed estimated nutrient supply rates, suggesting that projected productivity increases may be unrealistically high. Accounting for nitrogen and nitrogen-phosphorus limitation lowers projected end-of-century estimates of net primary productivity by 19% and 25%, respectively, and turns the land surface into a net source of CO2 by 2100. We conclude that potential effects of nutrient limitation must be considered in estimates of the terrestrial carbon sink strength through the twenty-first century.

  12. Production of carbon-13-labeled cadaverine by engineered Corynebacterium glutamicum using carbon-13-labeled methanol as co-substrate.

    PubMed

    Lemeier, Lennart; Pfeifenschneider, Johannes; Carnicer, Marc; Heux, Stephanie; Portais, Jean-Charles; Wendisch, Volker F

    2015-12-01

    Methanol, a one-carbon compound, can be utilized by a variety of bacteria and other organisms as carbon and energy source and is regarded as a promising substrate for biotechnological production. In this study, a strain of non-methylotrophic Corynebacterium glutamicum, which was able to produce the polyamide building block cadaverine as non-native product, was engineered for co-utilization of methanol. Expression of the gene encoding NAD(+)-dependent methanol dehydrogenase (Mdh) from the natural methylotroph Bacillus methanolicus increased methanol oxidation. Deletion of the endogenous aldehyde dehydrogenase genes ald and fadH prevented methanol oxidation to carbon dioxide and formaldehyde detoxification via the linear formaldehyde dissimilation pathway. Heterologous expression of genes for the key enzymes hexulose-6-phosphate synthase and 6-phospho-3-hexuloisomerase of the ribulose monophosphate (RuMP) pathway in this strain restored growth in the presence of methanol or formaldehyde, which suggested efficient formaldehyde detoxification involving RuMP key enzymes. While growth with methanol as sole carbon source was not observed, the fate of (13)C-methanol added as co-substrate to sugars was followed and the isotopologue distribution indicated incorporation into central metabolites and in vivo activity of the RuMP pathway. In addition, (13)C-label from methanol was traced to the secreted product cadaverine. Thus, this synthetic biology approach led to a C. glutamicum strain that converted the non-natural carbon substrate methanol at least partially to the non-native product cadaverine. PMID:26276544

  13. Activated carbon/enhanced biological treatment of a complex groundwater

    SciTech Connect

    Pugh, L.B.; Rediske, R.R.; Rogers, D.R.; Peden, D.H.

    1996-12-31

    Impacted groundwater at the Ott/Story/Cordova Superfund site near Muskegon, Michigan contains a complex mixture of organic compounds and nitrogen. The remediation plan for the site calls for extraction and treatment of 4,600 cubic meters per day of groundwater, estimated to contain 1,500 mg/L of chemical oxygen demand (COD) and 80 mg/L of ammonia-nitrogen. Approximately 30% of the COD is comprised of a mixture of 50 Appendix IX compounds, including halogenated and aromatic orcanics. The remaining COD is contributed by an unidentified group of process intermediates and degradation products related to historical production at this former chemical production facility. The objectives for discharge of the treated Groundwater to a local surface water body included removal of known organic compounds and ammonia-nitrogen, as well as numerous unidentified compounds in the site groundwater. The purpose of this work was to evaluate the effectiveness of two activated carbon-enhanced biological treatment systems: granular activated Carbon/fluidized bed (GAC/FB) and powdered activated carbon treatment (PACT{reg_sign}) for achieving the expected standards for surface water discharge. GAC/FB and PACT were initially evaluated using laboratory-scale reactors. The GAC/FB reactor achieved consistent, high removals of all organic compounds; however, consistent nitrification could not be maintained. The two-stage PACT system achieved nearly complete removal of all organic compounds and ammonia. A 9.5-L/minute pilot system was subsequently operated at the site to provide additional performance information for the two-stage PACT process. Three of the most highly impacted site wells were used to supply groundwater to the pilot system. Excellent removal of all known and unknown organic compounds, and nearly complete nitrification was consistently achieved. As a result of the on-site pilot study, a two-stage PACT system is being implemented at the site.

  14. Thermal conversion of municipal solid waste via hydrothermal carbonization: Comparison of carbonization products to products from current waste management techniques

    SciTech Connect

    Lu Xiaowei; Jordan, Beth; Berge, Nicole D.

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer Hydrothermal carbonization (HTC) is a novel thermal conversion process. Black-Right-Pointing-Pointer HTC converts wastes into value-added resources. Black-Right-Pointing-Pointer Carbonization integrates majority of carbon into solid-phase. Black-Right-Pointing-Pointer Carbonization results in a hydrochar with high energy density. Black-Right-Pointing-Pointer Using hydrochar as an energy source may be beneficial. - Abstract: Hydrothermal carbonization (HTC) is a novel thermal conversion process that may be a viable means for managing solid waste streams while minimizing greenhouse gas production and producing residual material with intrinsic value. HTC is a wet, relatively low temperature (180-350 Degree-Sign C) thermal conversion process that has been shown to convert biomass to a carbonaceous residue referred to as hydrochar. Results from batch experiments indicate HTC of representative waste materials is feasible, and results in the majority of carbon (45-75% of the initially present carbon) remaining within the hydrochar. Gas production during the batch experiments suggests that longer reaction periods may be desirable to maximize the production of energy-favorable products. If using the hydrochar for applications in which the carbon will remain stored, results suggest that the gaseous products from HTC result in fewer g CO{sub 2}-equivalent emissions than the gases associated with landfilling, composting, and incineration. When considering the use of hydrochar as a solid fuel, more energy can be derived from the hydrochar than from the gases resulting from waste degradation during landfilling and anaerobic digestion, and from incineration of food waste. Carbon emissions resulting from the use of the hydrochar as a fuel source are smaller than those associated with incineration, suggesting HTC may serve as an environmentally beneficial alternative to incineration. The type and extent of environmental benefits derived from HTC will be dependent on hydrochar use/the purpose for HTC (e.g., energy generation or carbon storage).

  15. Carbon dioxide supersaturation promotes primary production in lakes.

    PubMed

    Jansson, Mats; Karlsson, Jan; Jonsson, Anders

    2012-06-01

    A majority of the world's lakes are supersaturated with respect to carbon dioxide (CO(2) ). By experimental manipulation of the CO(2) concentration in supersaturated boreal lakes, we demonstrate that phytoplankton primary production was up to 10 times higher in supersaturated lake water in comparison with water with CO(2) at equilibrium concentrations and that CO(2) , together with nutrients, explained most of the variation in pelagic primary production and phytoplankton biomass over a wide variety of unproductive lakes. These results suggest that phytoplankton can be co-limited by CO(2) and nutrients in unproductive lakes. As import of terrestrial organic carbon and its subsequent microbial mineralisation in lakes is a driving force of CO(2) -supersaturation our results suggest that lake productivity and carbon cycling may respond to variations in terrestrial organic carbon export, (e.g. caused by land use or climate change) in ways not described before. PMID:22420750

  16. Evaluation of NOAA Carbon Tracker Global Carbon Dioxide Products

    NASA Astrophysics Data System (ADS)

    Nayak, R. K.; Deepthi, E. N.; Dadhwal, V. K.; Rao, K. H.; Dutt, C. B. S.

    2014-11-01

    Inter-comparison between National Oceanic and Atmospheric Administration Carbon Tracker (NOAACT) CO2 with satellite observations were carried out in this study. The satellite observations used here are mid troposphere CO2 based on Atmosphere Infrared Sounder (AIRS) on board NASA's Aqua and lower troposphere CO2 based on Greenhouse-gas Observing Satellite (GOSAT) of Japanese Aerospace Exploration Agency (JAXA). There exists good agreement between the seasonal cycles as estimated by NOAACT and Satellite observations. The mid troposphere CO2 exhibits distinct annual cycle in the northern hemisphere with positive detrended value during January-June and negative values during July-December. In the southern hemisphere, the annual cycle is less prominent and opposite phase with respect to the northern hemisphere. The lower tropospheric CO2 in both the hemispheres exhibits mixed signature of annual and semi-annual cycle. The amplitudes of the variability are significantly larger in the northern hemisphere than the southern hemisphere. The inter-annual variability of annual growth rates from the NOAACT is comparable with satellite observations however NOAACT could not resolved the spatial patterns of long-term growth rate as observed in the satellite observations.

  17. The mechanism of elution of gold cyanide from activated carbon

    NASA Astrophysics Data System (ADS)

    van Deventer, J. S. J.; van der Merwe, P. F.

    1994-12-01

    Numerous articles have appeared on the mechanism of the adsorption of gold cyanide onto activated carbon. In contrast, little information is available on the mechanism of elution of the adsorbed gold. It is the objective of this article to formulate such a mechanism on the basis of batch and column elution tests without analyzing adsorbed species on the carbon directly. The presence of spectator cations (M n+) enhances the formation of M n+{Au(CN){2/-}} n ion pairs on the carbon, which in turn suppress the elution of gold cyanide. The dynamics of removal of these cations determine the horizontal position of the gold peak in an elution profile. When the concentration of cations in the eluant is high and no cyanide is present in the solution or on the carbon, very little desorption of gold is observed. The quantitative effect of the concentration of spectator cations on the equilibrium for desorption of aurocyanide can be estimated from the elution profiles for gold and cations. Free cyanide in the eluant, which causes some competitive adsorption of cyanide with aurocyanide, therefore plays a minor role at the elevated temperatures used in industry. A more important effect of cyanide is its reaction with functional groups on the carbon, the products of which passivate the surface for adsorption of aurocyanide, and thereby cyanide promotes the elution of aurocyanide. The degree of passivation, which is determined to a large extent by the temperature of pretreatment, also affects the elution of cations and the degradation/adsorption of cyanide itself. Reactivation of the carbon surface occurs when the adsorbed/decomposed cyanide is removed by the eluant. At high temperatures of pretreatment, such as used in practice, it is not necessary to include a reactivation term in the mathematical model for elution.

  18. A trimodal porous carbon as an effective catalyst for hydrogen production by methane decomposition.

    PubMed

    Shen, Yi; Lua, Aik Chong

    2016-01-15

    A new type of porous carbon with an interconnected trimodal pore system is synthesized by a nanocasting method using nanoparticulated bimodal micro-mesoporous silica particles as the template. The synthesized template and carbon material are characterized using transmission electron microscopy (TEM), field emission electron scanning microscopy (FESEM) and nitrogen adsorption-desorption test. The synthesized carbon material has an extremely high surface area, a large pore volume and an interconnected pore structure, which could provide abundant active sites and space for chemical reactions and minimize the diffusion resistance of the reactants. The resulting carbon is used as the catalyst for hydrogen production by the thermal decomposition of methane. The catalytic results show that the as-synthesized carbon in this study produces much higher methane conversion and hydrogen yield than the commercial carbon materials. PMID:26433477

  19. 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.

  20. Production and screening of carbon products precursors from coal. Quarterly progress report, July 1, 1996--September 30, 1996

    SciTech Connect

    Zondlo, J.; Stiller, A.

    1996-10-25

    This quarterly report covers activities during the period from July 1, 1996 through September 30, 1996 on the development of carbon products precursor materials from coal. The first year of the project ended in February, 1996; however, the WVU research effort continued through August 14, 1997 on a no-cost extension of the original contract. PETC chose to exercise the option for continuation of the projects and $100,000 became available on August 9, 1996. The objective for year two is to focus on development of those carbon products from coal-based solvent extract precursors which have the greatest possibility for commercial success.

  1. LOW COST PRODUCTION OF CARBON FIBERS FROM LIGNIN MATERIALS

    SciTech Connect

    Gallego, Nidia C; Baker, Darren A; Baker, Frederick S

    2009-01-01

    The DOE Vehicle Technologies-funded work at ORNL is directed to the development of processes for the low cost production of carbon fibers. The objective of the project is to develop more energy-efficient, cost-effective processes for production of carbon fibers for use in composite materials for vehicles, which would substantially reduce vehicle weight, increase vehicle fuel economy, and result in lower CO2 emissions. Carbon fibers have the potential for substantial weight saving in vehicles because of their remarkable high strength, high modulus, and low density. However, carbon fibers are currently too expensive for large scale automotive use, which necessitates a large reduction in the cost of commercial grade fiber from about $20/lb to $5-7/lb. Lignin, a renewable resource material, has significant potential as a precursor material for low cost carbon fiber production. In this paper we report on progress to demonstrate the melt-spinning of precursor fibers from various lignin sources, the subsequent processing of the lignin precursor fibers into carbon fibers, and carbon fiber properties.

  2. Granular activated-carbon treatment. Engineering bulletin

    SciTech Connect

    Not Available

    1991-10-01

    Granular activated carbon (GAC) treatment is a physicochemical process that removes a wide variety of contaminants by adsorbing them from liquid and gas streams. The treatment is most commonly used to separate organic contaminants from water or air; however, it can be used to remove a limited number of inorganic contaminants. In most cases, the contaminants are collected in concentrated form on the GAC, and further treatment is required. Site-specific treatability studies are generally necessary to document the applicability and potential performance of a GAC system. The bulletin provides information on the technology applicability, technology limitations, a technology description, the types of residuals produced, site requirements, latest performance data, status of the technology, and sources for further information.

  3. Production of single-walled carbon nanotube grids

    DOEpatents

    Hauge, Robert H; Xu, Ya-Qiong; Pheasant, Sean

    2013-12-03

    A method of forming a nanotube grid includes placing a plurality of catalyst nanoparticles on a grid framework, contacting the catalyst nanoparticles with a gas mixture that includes hydrogen and a carbon source in a reaction chamber, forming an activated gas from the gas mixture, heating the grid framework and activated gas, and controlling a growth time to generate a single-wall carbon nanotube array radially about the grid framework. A filter membrane may be produced by this method.

  4. 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 700C. These pyrolysis conditions for preparing the activated carbons are found to yield higher BET surface area at a pyrolysis temperature of 700C 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

  5. 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. PMID:23737721

  6. Net carbon flux in organic and conventional olive production systems

    NASA Astrophysics Data System (ADS)

    Saeid Mohamad, Ramez; Verrastro, Vincenzo; Bitar, Lina Al; Roma, Rocco; Moretti, Michele; Chami, Ziad Al

    2014-05-01

    Agricultural systems are considered as one of the most relevant sources of atmospheric carbon. However, agriculture has the potentiality to mitigate carbon dioxide mainly through soil carbon sequestration. Some agricultural practices, particularly fertilization and soil management, can play a dual role in the agricultural systems regarding the carbon cycle contributing to the emissions and to the sequestration process in the soil. Good soil and input managements affect positively Soil Organic Carbon (SOC) changes and consequently the carbon cycle. The present study aimed at comparing the carbon footprint of organic and conventional olive systems and to link it to the efficiency of both systems on carbon sequestration by calculating the net carbon flux. Data were collected at farm level through a specific and detailed questionnaire based on one hectare as a functional unit and a system boundary limited to olive production. Using LCA databases particularly ecoinvent one, IPCC GWP 100a impact assessment method was used to calculate carbon emissions from agricultural practices of both systems. Soil organic carbon has been measured, at 0-30 cm depth, based on soil analyses done at the IAMB laboratory and based on reference value of SOC, the annual change of SOC has been calculated. Substracting sequestrated carbon in the soil from the emitted on resulted in net carbon flux calculation. Results showed higher environmental impact of the organic system on Global Warming Potential (1.07 t CO2 eq. yr-1) comparing to 0.76 t CO2 eq. yr-1 in the conventional system due to the higher GHG emissions caused by manure fertilizers compared to the use of synthetic foliar fertilizers in the conventional system. However, manure was the main reason behind the higher SOC content and sequestration in the organic system. As a resultant, the organic system showed higher net carbon flux (-1.7 t C ha-1 yr-1 than -0.52 t C ha-1 yr-1 in the conventional system reflecting higher efficiency as a sink for atmospheric CO2 (the negative value of Net C flux indicates that a system is a net sink for atmospheric CO2). In conclusion, this study illustrates the importance of including soil carbon sequestration associated with CO2 emissions in the evaluation process between alternatives of agricultural systems. Thus, organic olive system offers an opportunity to increase carbon sequestration compared to the conventional one although it causes higher C emissions from manure fertilization. Keywords: Net carbon flux, GHG, organic, olive, soil organic carbon

  7. Beech carbon productivity as driver of ectomycorrhizal abundance and diversity.

    PubMed

    Druebert, Christine; Lang, Christa; Valtanen, Kerttu; Polle, Andrea

    2009-08-01

    We tested the hypothesis that carbon productivity of beech (Fagus sylvatica) controls ectomycorrhizal colonization, diversity and community structures. Carbon productivity was limited by long-term shading or by girdling. The trees were grown in compost soil to avoid nutrient deficiencies. Despite severe limitation in photosynthesis and biomass production by shading, the concentrations of carbohydrates in roots were unaffected by the light level. Shade-acclimated plants were only 10% and sun-acclimated plants were 74% colonized by ectomycorrhiza. EM diversity was higher on roots with high than at roots with low mycorrhizal colonization. Evenness was unaffected by any treatment. Low mycorrhizal colonization had no negative effects on plant mineral nutrition. In girdled plants mycorrhizal colonization and diversity were retained although (14)C-leaf feeding showed almost complete disruption of carbon transport from leaves to roots. Carbohydrate storage pools in roots decreased upon girdling. Our results show that plant carbon productivity was the reason for and not the result of high ectomycorrhizal diversity. We suggest that ectomycorrhiza can be supplied by two carbon routes: recent photosynthate and stored carbohydrates. Storage pools may be important for ectomycorrhizal survival when photoassimilates were unavailable, probably feeding preferentially less carbon demanding EM species as shifts in community composition were found. PMID:19344334

  8. Carbon Monoxide Production by a Bathypelagic Siphonophore.

    PubMed

    Pickwell, G V; Barham, E G; Wilton, J W

    1964-05-15

    A physonectid siphonophore, Nanomia bijuga, associated with a verticallymigrating deep scattering layer, has been observed with a gasfilled float at depths in excess of 300 meters in the sea. This implies that gas is secreted and maintained in the pneumatophore against a diffusion gradient of 30 atmospheres or more. Analysis of the enclosed gases revealed concentrations of carbon monoxide exceeding 90 percent. Necessary voiding of this gas during a vertical ascent of 300 meters could give rise to a transient population of bubbles which would act as sound-reflecting targets. PMID:17733619

  9. CYANIDE REMOVAL FROM REFINERY WASTEWATER USING POWDERED ACTIVATED CARBON

    EPA Science Inventory

    The objective of this project was to evaluate the removal of low level cyanide in petroleum refinery wastewater by the addition of powdered activated carbon and cupric chloride to an activated sludge unit. The activated carbon and cupric chloride act as a catalyst in the oxidatio...

  10. New natural product carbonic anhydrase inhibitors incorporating phenol moieties.

    PubMed

    Karioti, Anastasia; Ceruso, Mariangela; Carta, Fabrizio; Bilia, Anna-Rita; Supuran, Claudiu T

    2015-11-15

    Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the fundamental reaction of CO2 hydration in all living organisms, being actively involved in the regulation of a plethora of patho/physiological conditions. They represent a typical example of enzyme convergent evolution, as six genetically unrelated families of such enzymes were described so far. The need to find selective CA inhibitors (CAIs) triggered the investigation of natural product libraries, which proved to be a valid source of agents with such an activity, as demonstrated for the phenols, polyamines and coumarins. Herein we report an in vitro inhibition study of human (h) CA isoforms hCAs I, II, IV, VII and XII with a panel of natural polyphenols including flavones, flavonols, flavanones, flavanols, isoflavones and depsides, some of which extracted from Quercus ilex and Salvia miltiorrhiza. Several of the investigated derivatives showed interesting inhibition activity and selectivities for inhibiting some important isoforms over the off-target ones hCA I and II. PMID:26498393

  11. Production of superconductor/carbon bicomponent fibers

    NASA Technical Reports Server (NTRS)

    Wise, S. A.; Fain, C. C.; Leigh, H. D.

    1991-01-01

    Certain materials are unable to be drawn or spun into fiber form due to their improper melting characteristics or brittleness. However, fibrous samples of such materials are often necessary for the fabrication of intricate shapes and composites. In response to this problem, a unique process, referred to as the piggyback process, was developed to prepare fibrous samples of a variety of nonspinnable ceramics. In this technique, specially produced C shaped carbon fibers serve as micromolds to hold the desired materials prior to sintering. Depending on the sintering atmosphere used, bicomponent or single component fibers result. While much has been shown worldwide concerning the YBa2Cu3O(7-x) superconductor, fabrication into unique forms has proven quite difficult. However, a variety of intricate shapes are necessary for rapid commercialization of the superconducting materials. The potential for producing fibrous samples of the YBa2Cu3O(7-x) compound by the piggyback process is being studied. Various organic and acrylic materials were studied to determine suspending ability, reactivity with the YBa2Cu3O(7-x) compound during long term storage, and burn out characteristics. While many questions were answered with respect to the interfacial reactions between YBa2Cu3O(7-x) and carbon, much work is still necessary to improve the quality of the sintered material if the fibers produced are to be incorporated into useful composite or cables.

  12. Microbial Methane Production Associated with Carbon Steel Corrosion in a Nigerian Oil Field

    PubMed Central

    Mand, Jaspreet; Park, Hyung S.; Okoro, Chuma; Lomans, Bart P.; Smith, Seun; Chiejina, Leo; Voordouw, Gerrit

    2016-01-01

    Microbially influenced corrosion (MIC) in oil field pipeline systems can be attributed to many different types of hydrogenotrophic microorganisms including sulfate reducers, methanogens and acetogens. Samples from a low temperature oil reservoir in Nigeria were analyzed using DNA pyrotag sequencing. The microbial community compositions of these samples revealed an abundance of anaerobic methanogenic archaea. Activity of methanogens was demonstrated by incubating samples anaerobically in a basal salts medium, in the presence of carbon steel and carbon dioxide. Methane formation was measured in all enrichments and correlated with metal weight loss. Methanogens were prominently represented in pipeline solids samples, scraped from the inside of a pipeline, comprising over 85% of all pyrosequencing reads. Methane production was only witnessed when carbon steel beads were added to these pipeline solids samples, indicating that no methane was formed as a result of degradation of the oil organics present in these samples. These results were compared to those obtained for samples taken from a low temperature oil field in Canada, which had been incubated with oil, either in the presence or in the absence of carbon steel. Again, methanogens present in these samples catalyzed methane production only when carbon steel was present. Moreover, acetate production was also found in these enrichments only in the presence of carbon steel. From these studies it appears that carbon steel, not oil organics, was the predominant electron donor for acetate production and methane formation in these low temperature oil fields, indicating that the methanogens and acetogens found may contribute significantly to MIC. PMID:26793176

  13. Microbial Methane Production Associated with Carbon Steel Corrosion in a Nigerian Oil Field.

    PubMed

    Mand, Jaspreet; Park, Hyung S; Okoro, Chuma; Lomans, Bart P; Smith, Seun; Chiejina, Leo; Voordouw, Gerrit

    2015-01-01

    Microbially influenced corrosion (MIC) in oil field pipeline systems can be attributed to many different types of hydrogenotrophic microorganisms including sulfate reducers, methanogens and acetogens. Samples from a low temperature oil reservoir in Nigeria were analyzed using DNA pyrotag sequencing. The microbial community compositions of these samples revealed an abundance of anaerobic methanogenic archaea. Activity of methanogens was demonstrated by incubating samples anaerobically in a basal salts medium, in the presence of carbon steel and carbon dioxide. Methane formation was measured in all enrichments and correlated with metal weight loss. Methanogens were prominently represented in pipeline solids samples, scraped from the inside of a pipeline, comprising over 85% of all pyrosequencing reads. Methane production was only witnessed when carbon steel beads were added to these pipeline solids samples, indicating that no methane was formed as a result of degradation of the oil organics present in these samples. These results were compared to those obtained for samples taken from a low temperature oil field in Canada, which had been incubated with oil, either in the presence or in the absence of carbon steel. Again, methanogens present in these samples catalyzed methane production only when carbon steel was present. Moreover, acetate production was also found in these enrichments only in the presence of carbon steel. From these studies it appears that carbon steel, not oil organics, was the predominant electron donor for acetate production and methane formation in these low temperature oil fields, indicating that the methanogens and acetogens found may contribute significantly to MIC. PMID:26793176

  14. Clouds Versus Carbon: Predicting Vegetation Roughness by Maximizing Productivity

    NASA Technical Reports Server (NTRS)

    Olsen, Lola M.

    2004-01-01

    Surface roughness is one of the dominant vegetation properties that affects land surface exchange of energy, water, carbon, and momentum with the overlying atmosphere. We hypothesize that the canopy structure of terrestrial vegetation adapts optimally to climate by maximizing productivity, leading to an optimum surface roughness. An optimum should exist because increasing values of surface roughness cause increased surface exchange, leading to increased supply of carbon dioxide for photosynthesis. At the same time, increased roughness enhances evapotranspiration and cloud cover, thereby reducing the supply of photosynthetically active radiation. We demonstrate the optimum through sensitivity simulations using a coupled dynamic vegetation-climate model for present day conditions, in which we vary the value of surface roughness for vegetated surfaces. We find that the maximum in productivity occurs at a roughness length of 2 meters, a value commonly used to describe the roughness of today's forested surfaces. The sensitivity simulations also illustrate the strong climatic impacts of vegetation roughness on the energy and water balances over land: with increasing vegetation roughness, solar radiation is reduced by up to 20 W/sq m in the global land mean, causing shifts in the energy partitioning and leading to general cooling of the surface by 1.5 K. We conclude that the roughness of vegetated surfaces can be understood as a reflection of optimum adaptation, and it is associated with substantial changes in the surface energy and water balances over land. The role of the cloud feedback in shaping the optimum underlines the importance of an integrated perspective that views vegetation and its adaptive nature as an integrated component of the Earth system.

  15. 78 FR 35603 - Foreign-Trade Zone 83-Huntsville, Alabama; Application for Production Authority; Toray Carbon...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-13

    ...; Toray Carbon Fibers America, Inc.; (Polyacrylonitrile Fiber/Carbon Fiber Production), Decatur, Alabama... facility is used for the production of polyacrylonitrile (PAN)-based carbon fiber, and PAN fiber,...

  16. Economic Analysis of Planting Forests on Rice Lands in Texas: Sequestering Carbon and Avoiding Methane Production

    NASA Astrophysics Data System (ADS)

    Kronrad, G. D.; Huang, C.

    2005-12-01

    Global climate change is predicted due to increases in greenhouse gasses (i.e. CO2, CH4, CFCs, N2O, O3) in the atmosphere caused by human activities. The atmospheric concentration of methane (CH4), which absorbs and retains heat 21 times more effectively than CO2, has increased. Anaerobic bacterial activity in rice paddies constitutes one of major emission sources of CH4. The rice fields of Texas, for example, accounted for an annual CH4 emission of between 1.1 and 1.6 million tons of CO2 equivalent between 1990 and 2000. Converting marginal rice fields to forests plantations will remove CO2 from the atmosphere, sequester carbon in the forests and prevent the production of CH4. Therefore, carbon credits can be claimed for the carbon sequestered and the avoidance of CH4 production. Analyses were conducted to calculate the amount of carbon sequestered and methane avoided, and the profitability, measured in net present worth (NPW), of managing loblolly pine plantation for 1) timber production only, 2) the dual products of timber products and carbon credits in forests planted on marginal agricultural and unused pastureland and 3) the dual products of timber and carbon storage in forests planted on marginal rice lands. Calculations were performed using three discount rates, three site qualities and five prices for carbon credits. The results indicate that on average quality land, using a discount rate of 8 percent, forests planted on marginal agricultural and unused pastureland earn a NPW of 346 per acre from timber production only; a NPW of 438 per acre from timber and carbon credits (54.4 tons of carbon sequestered), assuming carbon is worth 10 per ton, during one rotation (32 years). The profitability of forest management increases due to the inclusion of carbon credits. The profitability of planting forests on marginal rice fields is even higher, earning a NPW of 566 per acre from timber and carbon credits (54.4 tons of C sequestered and 33.3 tons of C emission avoided).

  17. Production of Feruloyl Esterase from Aspergillus niger by Solid-State Fermentation on Different Carbon Sources

    PubMed Central

    Ou, Shiyi; Zhang, Jing; Wang, Yong; Zhang, Ning

    2011-01-01

    A mixture of wheat bran with maize bran as a carbon source and addition of (NH4)SO4 as nitrogen source was found to significantly increase production of feruloyl esterase (FAE) enzyme compared with wheat bran as a sole carbon and nitrogen source. The optimal conditions in conical flasks were carbon source (30?g) to water 1?:?1, maize bran to wheat bran 1?:?2, (NH4)SO4 1.2?g and MgSO4 70?mg. Under these conditions, FAE activity was 7.68?mU/g. The FAE activity on the mixed carbon sources showed, high activity against the plant cell walls contained in the cultures. PMID:21603274

  18. Oxidative degradation of trichloroethylene adsorbed on active carbons: Use of microwave energy

    SciTech Connect

    Varma, R.; Nandi, S.P.

    1991-01-01

    Chlorinated hydrocarbon compounds (CHCl), such as chlorinated alkanes/alkenes, benzene and biphenyl etc, represent an important fraction of the industrial hazardous wastes produced. Trichloroethylene (TCE) can be removed from waste streams by adsorption on active carbons. The primary objective of the present work was to study the detoxification in air-stream of TCE adsorbed on different types of active carbons using in situ microwave heating. A secondary objective was to examine the regeneration of used carbons from the effects of repeated cyclic operations (adsorption- detoxification). The experimental study has shown that trichloroethylene adsorbed on active carbon can be oxidatively degradated in presence of microwave radiation. Energy can be transferred efficiently to the reaction sites without losing heat to the surrounding vessel. One of the decomposition product of trichloroethylene is free chlorine which is held very strongly on active carbon. Hydrochloric acid on the other hand seems to be less strongly held and appears in large concentration in the exit gas. Production of free chlorine can be avoided by using chlorohydrocarbon mixed with sufficient internal hydrogen. This is also expected to minimize the problem of carbon regeneration encountered in this study. The results obtained from studies on the oxidative degradation of TCE under microwave radiation are promising in a number of respects: (1) the detoxification of TCE adsorbed on active carbon can be conducted at moderate (<400{degree}C) temperatures, and (2) the used carbon bed can be regenerated. A patent on the process has been issued. 9 refs., 2 figs., 2 tabs.

  19. Selective Catalytic Oxidation of Hydrogen Sulfide on Activated Carbons Impregnated with Sodium Hydroxide

    SciTech Connect

    Schwartz, Viviane; Baskova, Svetlana; Armstrong, Timothy R.

    2009-01-01

    Two activated carbons of different origin were impregnated with the solution of sodium hydroxide (NaOH) of various concentrations up to 10 wt %, and the effect of impregnation on the catalytic performance of the carbons was evaluated. The catalytic activity was analyzed in terms of the capacity of carbons for hydrogen sulfide (H2S) conversion and removal from hydrogen-rich fuel streams and the emission times of H2S and the products of its oxidation [e.g., sulfur dioxide (SO2) and carbonyl sulfide (COS)]. The results of impregnation showed a significant improvement in the catalytic activity of both carbons proportional to the amount of NaOH introduced. NaOH introduces hydroxyl groups (OH-) on the surface of the activated carbon that increase its surface reactivity and its interaction with sulfur-containing compounds.

  20. Active carbons and clean briquettes from the modified Kansk-Achinsk brown coal

    SciTech Connect

    Kuznetsov, P.N.; Kuznetsova, L.I.; Kontzevoi, A.A.; Pozharnikov, V.A.

    1996-12-31

    The effect of modification of Kansk Achinsk Brown coal by means of chemical and mechanical pretreatments as well as by hydrolyzed lignin addition on coal briquetting was studied. Coal briquettes were then pyrolyzed and steam activated at 700--800 C to prepare the active carbons. The main focus was to analyze how macromolecular structure of brown coal affect the properties of briquettes and the sorption and mechanical properties of activated carbons and to investigate the potential for the production of clean briquetted fuel and high performance carbon adsorbents through the directive modification of coal.

  1. Production of superconductor/carbon bicomponent fibers

    NASA Technical Reports Server (NTRS)

    Wise, S. A.; Fain, C. C.; Leigh, H. D.; Sherrill, M.

    1990-01-01

    Certain materials are unable to be drawn or spun into fiber form due to their improper melting characteristics or brittleness. However, fibrous samples of such materials are often necessary for the fabrication of intricate shapes and composites. In response to this problem, a unique process, referred to as the piggyback process, was developed to prepare fibrous samples of a variety of nonspinnable ceramics. In this technique, specially produced C-shaped carbon fibers serve as micromolds to hold the desired materials prior to sintering. Depending on the sintering atmosphere used, bicomponent or single component fibers result. While much has been demonstrated worldwide concerning the YBa2Cu3O(7-x) superconductor, fabrication into unique forms has proven quite difficult. However, a variety of intricate shapes are necessary for rapid commercialization of the superconducting materials. The potential for producing fibrous samples of the YBa2Cu3O(7-x) compound by the piggyback process is being investigated. Various organic and acrylic materials were investigated to determine suspending ability, reactivity with the YBa2Cu3O(7-x) compound during long term storage, and burn out characteristics. While many questions were answered with respect to the interfacial reactions between YBa2Cu3O(7-x) and carbon, much work is still necessary to improve the quality of the sintered material if the fibers produced are to be incorporated into useful composites or cables. Additional research is necessary to evaluate quality of the barrier layer during long soakings at the peak temperature; adjust the firing schedule to avoid microcracking and improve densification; and increase the solids loading in the superconductive suspension to decrease porosity.

  2. DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS

    SciTech Connect

    Elliot B. Kennel; Stephen P. Carpenter; Dady Dadyburjor; Manoj Katakdaunde; Liviu Magean; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

    2005-06-08

    The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. These carbon products include materials used in metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. During this reporting period, efforts have focused on the development of continuous processes for hydrogenation as well as continuous production of carbon foam and coke.

  3. DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS

    SciTech Connect

    Elliot B. Kennel; Stephen P. Carpenter; Dady Dadyburjor; Manoj Katakdaunde; Liviu Magean; Madhavi Nallani-Chakravartula; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

    2006-03-27

    The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. These carbon products include materials used in metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. During this reporting period, efforts have focused on the development of continuous processes for hydrogenation as well as continuous production of carbon foam and coke.

  4. Synthesis of fluorescent carbon nanoparticles directly from active carbon via a one-step ultrasonic treatment

    SciTech Connect

    Li, Haitao; He, Xiaodie; Liu, Yang; Department of Chemistry, Northeast Normal University, Changchun 130024 ; Yu, Hang; Kang, Zhenhui; Department of Chemistry, Northeast Normal University, Changchun 130024 ; Lee, Shuit-Tong

    2011-01-15

    Water-soluble fluorescent carbon nanoparticles were synthesized directly from active carbon by a one-step hydrogen peroxide-assisted ultrasonic treatment. The carbon nanoparticles were characterized by transmission electron microscopy, optical fluorescent microscopy, fluorescent spectroscopy, Fourier transform infrared spectroscopy and ultraviolet-visible spectrophotometer. The results showed that the surface of carbon nanoparticles was rich of hydroxyl groups resulting in high hydrophilicity. The carbon nanoparticles could emit bright and colorful photoluminescence covering the entire visible-to-near infrared spectral range. Furthermore, these carbon nanoparticles also had excellent up-conversion fluorescent properties.

  5. Removal of an endocrine disrupting chemical (17alpha-ethinyloestradiol) from wastewater effluent by activated carbon adsorption: effects of activated carbon type and competitive adsorption.

    PubMed

    Ifelebuegu, A O; Lester, J N; Churchley, J; Cartmell, E

    2006-12-01

    Granular activated carbon has been extensively used for the adsorption of organic micropollutants for potable water production. In this study the removal of an endocrine disrupting chemical from wastewater final effluent by three types of granular activated carbon (wood, coconut and coal based) has been investigated in batch adsorption experiments and correlated with the removal of chemical oxygen demand (COD), total organic carbon (TOC) and ultraviolet absorbance (UV). The results obtained demonstrated 17alpha-ethinyloestradiol (EE2) removals of 98.6%, 99.3%, and 96.4% were achieved by the coal based (ACo), coconut based (ACn) and wood based (AWd) carbons respectively at the lowest dose of carbon (0.1gl(-1)). The other adsorbates investigated all exhibited good removal. At an equilibrium concentration of 7mgl(-1) the COD adsorption capacities were 3.16mg g(-1), 4.8 mg g(-1) and 7.1 mg g(-1) for the wood, coconut and coal based carbons respectively. Overall, the order of removal efficiency of EE2 and the other adsorbates for the three activated carbons was ACn > ACo > AWd. The adsorption capacities of the carbons were found to be reduced by the effects of other competing adsorbates in the wastewater effluent. PMID:17285939

  6. Carbon footprint of dairy production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse gas (GHG) emissions and their potential impact on global warming has become an important national and international concern. Dairy production systems along with all other types of animal agriculture are recognized as a source of GHG. Although little information exists on the net GHG emiss...

  7. Biomass Crop Production: Benefits for Soil Quality and Carbon Sequestration

    SciTech Connect

    Bandaranayake, W.; Bock, B.R.; Houston, A.; Joslin, J.D.; Pettry, D.E.; Schoenholtz, S.; Thornton, F.C.; Tolbert, V.R.; Tyler, D.

    1999-08-29

    Research at three locations in the southeastern US is quantifying changes in soil quality and soil carbon storage that occur during production of biomass crops compared with row crops. After three growing seasons, soil quality improved and soil carbon storage increased on plots planted to cottonwood, sycamore, sweetgum with a cover crop, switchgrass, and no-till corn. For tree crops, sequestered belowground carbon was found mainly in stumps and large roots. At the TN site, the coarse woody organic matter storage belowground was 1.3 Mg ha{sup {minus}1}yr{sup {minus}1}, of which 79% was stumps and large roots and 21% fine roots. Switchgrass at the AL site also stored considerable carbon belowground as coarse roots. Most of the carbon storage occurred mainly in the upper 30 cw although coarse roots were found to depths of greater than 60 cm. Biomass crops contributed to improvements in soil physical quality as well as increasing belowground carbon sequestration. The distribution and extent of carbon sequestration depends on the growth characteristics and age of the individual biomass crop species. Time and increasing crop maturity will determine the potential of these biomass crops to significantly contribute to the overall national goal of increasing carbon sequestration and reducing greenhouse gas emissions.

  8. The production of phytolith-occluded carbon in China's forests: implications to biogeochemical carbon sequestration.

    PubMed

    Song, Zhaoliang; Liu, Hongyan; Li, Beilei; Yang, Xiaomin

    2013-09-01

    The persistent terrestrial carbon sink regulates long-term climate change, but its size, location, and mechanisms remain uncertain. One of the most promising terrestrial biogeochemical carbon sequestration mechanisms is the occlusion of carbon within phytoliths, the silicified features that deposit within plant tissues. Using phytolith content-biogenic silica content transfer function obtained from our investigation, in combination with published silica content and aboveground net primary productivity (ANPP) data of leaf litter and herb layer in China's forests, we estimated the production of phytolith-occluded carbon (PhytOC) in China's forests. The present annual phytolith carbon sink in China's forests is 1.70.4 Tg CO2 yr(-1) , 30% of which is contributed by bamboo because the production flux of PhytOC through tree leaf litter for bamboo is 3-80 times higher than that of other forest types. As a result of national and international bamboo afforestation and reforestation, the potential of phytolith carbon sink for China's forests and world's bamboo can reach 6.81.5 and 27.06.1 Tg CO2 yr(-1) , respectively. Forest management practices such as bamboo afforestation and reforestation may significantly enhance the long-term terrestrial carbon sink and contribute to mitigation of global climate warming. PMID:23729188

  9. Calcium Carbonate Production by Coccolithophorid Algae in Long Term, Carbon Dioxide Sequestration

    SciTech Connect

    V.J. Fabry

    2005-04-29

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  10. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V.J. Fabry, Ph.D.

    2003-04-15

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  11. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V. J. Fabry

    2003-10-30

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds or bioreactors to abate CO{sub 2} emissions from power plants.

  12. Calcium Carbonate Production by Coccolithophorid Algae in Long Term, Carbon Dioxide Sequestration

    SciTech Connect

    V. J. Fabry

    2006-06-30

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  13. Calcium Carbonate Production by Coccolithophorid Alge in Long Term Carbon Dioxide Sequestration

    SciTech Connect

    V. J. Fabry

    2006-09-30

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  14. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V.J. Fabry, Ph.D.

    2003-07-15

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  15. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V.J. Fabry, Ph.D.

    2002-12-15

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  16. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V.J. Fabry

    2004-10-30

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds or bioreactors to abate CO{sub 2} emissions from power plants.

  17. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V. J. Fabry

    2005-01-24

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids ? single-celled, marine algae that are the major global producers of calcium carbonate ? to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  18. CALCIUM CARBONATE PRODUCTION BY COCCOLITHAPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V. J.Fabry

    2004-01-30

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  19. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V.J. Fabry, Ph.D.

    2002-09-30

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  20. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V.J. Fabry, Ph.D.

    2002-07-09

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids--single-celled, marine algae that are the major global producers of calcium carbonate--to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  1. CALCIUM CARBONATE PRODUCTION BY COCCOLITHOPHORID ALGAE IN LONG TERM, CARBON DIOXIDE SEQUESTRATION

    SciTech Connect

    V.J. Fabry

    2004-04-26

    Predictions of increasing levels of anthropogenic carbon dioxide (CO{sub 2}) and the specter of global warming have intensified research efforts to identify ways to sequester carbon. A number of novel avenues of research are being considered, including bioprocessing methods to promote and accelerate biosequestration of CO{sub 2} from the environment through the growth of organisms such as coccolithophorids, which are capable of sequestering CO{sub 2} relatively permanently. Calcium and magnesium carbonates are currently the only proven, long-term storage reservoirs for carbon. Whereas organic carbon is readily oxidized and releases CO{sub 2} through microbial decomposition on land and in the sea, carbonates can sequester carbon over geologic time scales. This proposal investigates the use of coccolithophorids single-celled, marine algae that are the major global producers of calcium carbonate to sequester CO{sub 2} emissions from power plants. Cultivation of coccolithophorids for calcium carbonate (CaCO{sub 3}) precipitation is environmentally benign and results in a stable product with potential commercial value. Because this method of carbon sequestration does not impact natural ecosystem dynamics, it avoids controversial issues of public acceptability and legality associated with other options such as direct injection of CO{sub 2} into the sea and ocean fertilization. Consequently, cultivation of coccolithophorids could be carried out immediately and the amount of carbon sequestered as CaCO{sub 3} could be readily quantified. The significant advantages of this approach warrant its serious investigation. The major goals of the proposed research are to identify the growth conditions that will result in the maximum amount of CO{sub 2} sequestration through coccolithophorid calcite production and to evaluate the costs/benefits of using coccolithophorid cultivation ponds to abate CO{sub 2} emissions from power plants.

  2. 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.

  3. Activated Carbon Modified with Copper for Adsorption of Propanethiol

    PubMed Central

    Moreno-Pirajn, Juan Carlos; Tirano, Joaqun; 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

  4. Carbon footprint and ammonia emissions of California beef production systems.

    PubMed

    Stackhouse-Lawson, K R; Rotz, C A; Oltjen, J W; Mitloehner, F M

    2012-12-01

    Beef production is a recognized source of greenhouse gas (GHG) and ammonia (NH(3)) emissions; however, little information exists on the net emissions from beef production systems. A partial life cycle assessment (LCA) was conducted using the Integrated Farm System Model (IFSM) to estimate GHG and NH(3) emissions from representative beef production systems in California. The IFSM is a process-level farm model that simulates crop growth, feed production and use, animal growth, and the return of manure nutrients back to the land to predict the environmental impacts and economics of production systems. Ammonia emissions are determined by summing the emissions from animal housing facilities, manure storage, field applied manure, and direct deposits of manure on pasture and rangeland. All important sources and sinks of methane, nitrous oxide, and carbon dioxide are predicted from primary and secondary emission sources. Primary sources include enteric fermentation, manure, cropland used in feed production, and fuel combustion. Secondary emissions occur during the production of resources used on the farm, which include fuel, electricity, machinery, fertilizer, and purchased animals. The carbon footprint is the net exchange of all GHG in carbon dioxide equivalent (CO(2)e) units per kg of HCW produced. Simulated beef production systems included cow-calf, stocker, and feedlot phases for the traditional British beef breeds and calf ranch and feedlot phases for Holstein steers. An evaluation of differing production management strategies resulted in ammonia emissions ranging from 98 13 to 141 27 g/kg HCW and carbon footprints of 10.7 1.4 to 22.6 2.0 kg CO(2)e/kg HCW. Within the British beef production cycle, the cow-calf phase was responsible for 69 to 72% of total GHG emissions with 17 to 27% from feedlot sources. Holstein steers that entered the beef production system as a by-product of dairy production had the lowest carbon footprint because the emissions associated with their mothers were primarily attributed to milk rather than meat production. For the Holstein system, the feedlot phase was responsible for 91% of the total GHG emission, while the calf-ranch phase was responsible for 7% with the remaining 2% from transportation. This simulation study provides baseline emissions data for California beef production systems and indicates where mitigation strategies can be most effective in reducing emissions. PMID:22952361

  5. Improvements in Production of Single-Walled Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Balzano, Leandro; Resasco, Daniel E.

    2009-01-01

    A continuing program of research and development has been directed toward improvement of a prior batch process in which single-walled carbon nanotubes are formed by catalytic disproportionation of carbon monoxide in a fluidized-bed reactor. The overall effect of the improvements has been to make progress toward converting the process from a batch mode to a continuous mode and to scaling of production to larger quantities. Efforts have also been made to optimize associated purification and dispersion post processes to make them effective at large scales and to investigate means of incorporating the purified products into composite materials. The ultimate purpose of the program is to enable the production of high-quality single-walled carbon nanotubes in quantities large enough and at costs low enough to foster the further development of practical applications. The fluidized bed used in this process contains mixed-metal catalyst particles. The choice of the catalyst and the operating conditions is such that the yield of single-walled carbon nanotubes, relative to all forms of carbon (including carbon fibers, multi-walled carbon nanotubes, and graphite) produced in the disproportionation reaction is more than 90 weight percent. After the reaction, the nanotubes are dispersed in various solvents in preparation for end use, which typically involves blending into a plastic, ceramic, or other matrix to form a composite material. Notwithstanding the batch nature of the unmodified prior fluidized-bed process, the fluidized-bed reactor operates in a continuous mode during the process. The operation is almost entirely automated, utilizing mass flow controllers, a control computer running software specific to the process, and other equipment. Moreover, an important inherent advantage of fluidized- bed reactors in general is that solid particles can be added to and removed from fluidized beds during operation. For these reasons, the process and equipment were amenable to modification for conversion from batch to continuous production.

  6. Acoustical Evaluation of Carbonized and Activated Cotton Nonwovens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The process of manufacturing a carbonized and activated nonwoven made by cotton fiber was investigated in this paper. The study was focused on the acoustic application and nonwoven composites with cotton nonwoven as a base layer and glass fiber nonwoven, cotton nonwoven, and carbonized and activated...

  7. [Flue gas desulfurization by a novel biomass activated carbon].

    PubMed

    Liu, Jie-Ling; Tang, Zheng-Guang; Chen, Jie; Jiang, Wen-Ju; Jiang, Xia

    2013-04-01

    A novel biomass columnar activated carbon was prepared from walnut shell and pyrolusite was added as a catalyst. The activated carbon prepared was used for flue gas desulphurization in a fixed-bed reactor with 16 g of activated carbon. The impact of operating parameters such as SO2 inlet concentration, space velocity, bed temperature, moisture content and O2 concentration on the desulfurization efficiency of activated carbon was investigated. The results showed that both the breakthrough sulfur capacity and breakthrough time of activated carbon decreased with the increase of SO2 inlet concentration within the range of 0.1% -0.3%. The breakthrough sulfur capacity deceased with the increase of space velocity, with optimal space velocity of 600 h(-1). The optimal bed temperature was 80 degrees C, and the desulfurization efficiency can be reduced if the temperature continue to increase. The presence of moisture and oxygen greatly promoted the adsorption of SO2 onto the activated carbon. The best moisture content was 10%. When the oxygen concentrations were between 10% and 13%, the desulfurization performance of activated carbon was the highest. Under the optimal operating conditions, the sulfur capacity of activated carbon was 252 mg x g(-1), and the breakthrough time was up to 26 h when the SO2 inlet concentration was 0.2%. PMID:23798152

  8. FOREST HARVESTS AND WOOD PRODUCTS: SOURCES AND SINKS OF ATMOSPHERIC CARBON DIOXIDE

    EPA Science Inventory

    Changes in the net carbon(c)sink-source balance related to a country's forest harvesting and use of wood products is an important component in making country-level inventories of greenhouse gas emissions,a current activity within many signatory nations to the UN Framework Convent...

  9. Physical activation of diatomite-templated carbons and its effect on the adsorption of methylene blue (MB)

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Yuan, Weiwei; Yuan, Peng; Yu, Wenbin; Tan, Daoyong; Liu, Hongmei; He, Hongping

    2013-10-01

    One- and two-step physical activation methods, using CO2 and H2O as activation agents, were performed to enhance the porosity of diatomite-templated carbons. The morphology, pore parameters, and adsorption capacity of diatomite-templated carbons before and after activation were investigated to evaluate the effects of activation. The results showed deconstruction of the macroporous structure occurred after one-step activation, while two-step activation retained the unique tubular and pillared macroporous structure of diatomite-templated carbon, indicating a highly promising activation method. The new-appearing pores after two-step activation were mainly micropores, which formed on the walls of carbon tubes and pillars. Pore parameters, such as the specific surface area and pore volume, as well as the micropore volume, showed a great increase after two-step activation and were 2-3 times larger than those of the original carbon. CO2 was more effective in enhancing the porosity than H2O during two-step activation, and the obtained carbon products had a higher specific surface area and pore volume. Moreover, the carbon products after two-step activation possessed a larger adsorption capacity of methylene blue than the original carbon; the maximum Langmuir adsorption capacity of MB on the CO2-activated carbon was 505.1 mg/g.

  10. 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 smaller ionic species to the solution. This Mg hybrid capacitor system demonstrated a stable cycle performance for many thousands of cycles with a specific capacitance of 90 Fg(-1) for the AC positive electrodes along a potential range of 2.4 V. (C) 2014 The Electrochemical Society. All rights reserved.

  11. A Carbon Arc Apparatus For Production Of Nanotubes In Microgravity

    NASA Technical Reports Server (NTRS)

    Alford, J. M.; Mason, G. R.; Feikema, D. A.

    2003-01-01

    Although many methods are available for production of single-walled carbon nanotubes (SWNTs), the conventional carbon arc process remains the most popular due to its simplicity and large production rate. However, high temperatures inside the carbon arc generate strong buoyancy driven convection, and it is hypothesized that the non-uniform environment created by this flow will have large effects on the growth and morphology of SWNTs produced by the arc process. Indeed, using normal gravity experiments, Marin et al. have demonstrated that changes in the buoyant convection plume produced by altering the arc electrode orientation can be used to change the diameter distribution of the SWNTs produced; an effect they attribute to changes in the temperature of the local nanotube growth environment. While these experiments present convincing evidence that buoyant convection has a strong effect on nanotube growth, normal gravity experiments are severely limited in scope. The ideal way to study the effect of buoyancy on SWNT production is to remove it completely. Toward this goal, a microgravity carbon arc reactor has been designed for use in the NASA Glenn 2.2 and 5 second drop towers. Although simple in principle, conventional carbon arc machines, which generally employ large reaction chambers and require heavy duty welding power supplies capable of supplying kilowatts of power, are not suitable for microgravity experiments. Here we describe a miniature carbon arc machine for SWNT production that fits into a conventional drop rig for use on the NASA Glenn 2.2 and 5 second drop towers, but that has a performance (production rate) that is better than most large ground-based machines.

  12. Use of carbon dioxide in the chemical synthesis technologies, plasma gasification and carbon production

    NASA Astrophysics Data System (ADS)

    Rutberg, Ph G.; Kuznetsov, V. A.; Bratsev, A. N.; Popov, V. E.; Shtengel', S. V.; Ufimtsev, A. A.

    2011-03-01

    The modern electric power sector is based on burning of carbonaceous substances (coal, oil, natural gas, etc.). Large power stations are powerful local sources of carbon dioxide. Inconstancy of the electric power demand leads to increase in CO2 specific emissions, as the output power is basically higher than required one by the power network. One of promising ways of increase of operating efficiency of power stations is use of surpluses of the generated electric power in plasma technologies. The paper deals with the opportunity to use the plasma technologies in processes of methanol and methane production from carbon dioxide. Comparison of ranges of key parameters of plasma gasification of wood by air, carbon dioxide, and steam is presented. Also, use of CO2 for pure carbon production is examined.

  13. Carbon dioxide sequestration by direct mineral carbonation: process mineralogy of feed and products

    SciTech Connect

    O'Connor, William K.; Dahlin, David C.; Rush, G.E.; Dahlin, Cheryl L.; Collins, W. Keith

    2001-01-01

    Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO2 (PCO2). Specific conditions include: 155?C; PCO2=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to characterize the feed and process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

  14. Electro-osmotic-based catholyte production by Microbial Fuel Cells for carbon capture.

    PubMed

    Gajda, Iwona; Greenman, John; Melhuish, Chris; Santoro, Carlo; Li, Baikun; Cristiani, Pierangela; Ieropoulos, Ioannis

    2015-12-01

    In Microbial Fuel Cells (MFCs), the recovery of water can be achieved with the help of both active (electro-osmosis), and passive (osmosis) transport pathways of electrolyte through the semi-permeable selective separator. The electrical current-dependent transport, results in cations and electro-osmotically dragged water molecules reaching the cathode. The present study reports on the production of catholyte on the surface of the cathode, which was achieved as a direct result of electricity generation using MFCs fed with wastewater, and employing Pt-free carbon based cathode electrodes. The highest pH levels (>13) of produced liquid were achieved by the MFCs with the activated carbon cathodes producing the highest power (309 μW). Caustic catholyte formation is presented in the context of beneficial cathode flooding and transport mechanisms, in an attempt to understand the effects of active and passive diffusion. Active transport was dominant under closed circuit conditions and showed a linear correlation with power performance, whereas osmotic (passive) transport was governing the passive flux of liquid in open circuit conditions. Caustic catholyte was mineralised to a mixture of carbonate and bicarbonate salts (trona) thus demonstrating an active carbon capture mechanism as a result of the MFC energy-generating performance. Carbon capture would be valuable for establishing a carbon negative economy and environmental sustainability of the wastewater treatment process. PMID:26343045

  15. Influence of surface properties on the mechanism of H2S removal by alkaline activated carbons.

    PubMed

    Yan, Rong; Chin, Terence; Ng, Yuen Ling; Duan, Huiqi; Liang, David Tee; Tay, Joo Hwa

    2004-01-01

    Alkaline activated carbons are widely used as adsorbents of hydrogen sulfide (H2S), one of the major odorous compounds arising from sewage treatment facilities. Although a number of studies have explored the effects of various parameters, mechanisms of H2S adsorption by alkaline carbons are not yet fully understood. The major difficulty seems to lie in the fact that little is known with certainty about the predominant reactions occurring on the carbon surface. In this study, the surface properties of alkaline activated carbons were systematically investigated to further exploit and better understand the mechanisms of H2S adsorption by alkaline activated carbons. Two commercially available alkaline activated carbons and their representative exhausted samples (8 samples collected at different height of the column after H2S breakthrough tests) were studied. The 8 portions of the exhausted carbon were used to represent the H2S/carbon reaction process. The surface properties of both the original and the exhausted carbons were characterized using the sorption of nitrogen (BET test), surface pH, Boehm titration, thermal and FTIR analysis. Porosity and surface area provide detailed information about the pore structure of the exhausted carbons with respect to the reaction extent facilitating the understanding of potential pore blockages. Results of Boehm titration and FTIR both demonstrate the significant effects of surface functional groups, and identification of oxidation products confirmed the different mechanisms involved with the two carbons. From the DTG curves of thermal analysis, two well-defined peaks representing two products of surface reactions (i.e., sulfur and sulfuric acid) were observed from the 8 exhausted portions with gradually changing patterns coinciding with the extent of the reaction. Surface pH values of the exhausted carbons show a clear trend of pH drop along the reaction extent, while pH around 2 was observed for the bottom of the bed indicating sulfuric acid as the predominant products. Although both carbons are coal-based and of KOH impregnated type, performances of different carbons differ significantly. A correlation is well established to link the reaction extent with various surface properties. In summary, not only the homogeneous alkali impregnation and physical porosity but also the carbon surface chemistry are significant factors influencing the performances of alkaline activated carbons as H2S adsorbents. PMID:14740753

  16. [Study on adsorption properties of organic vapor on activated carbons].

    PubMed

    Cai, Dao-Fei; Huang, Wei-Qiu; Wang, Dan-Li; Zhang, Lin; Yang, Guang

    2013-12-01

    Adsorption technology is widely used in oil vapor recovery, and adsorbents have decisive effect on separation. Three kinds of activated carbon (AC) were chosen to study their adsorption properties and adsorption energy, where n-hexane and n-heptane acted as adsorbate and adsorption experiments were conducted at 293.15 K. At the same time, regression formula of Logistic model was used to fit the throughout curves of active carbons. The results showed that: surface area and pore volume of activated carbon were the main factors affecting its adsorption properties; the adsorption behavior of n-hexane and n-heptane were corresponding to Langmuir adsorption isotherm model; adsorption energy of these three kinds of activated carbon became greater with increasing specific surface area. Fitting curve of Logistic model had high similarity with the experimental results, which could be used in the prediction of breakthrough curves of activated carbons. PMID:24640910

  17. Ozone Removal by Filters Containing Activated Carbon: A Pilot Study

    SciTech Connect

    Fisk, William; Spears, Mike; Sullivan, Douglas; Mendell, Mark

    2009-09-01

    This study evaluated the ozone removal performance of moderate-cost particle filters containing activated carbon when installed in a commercial building heating, ventilating, and air conditioning (HVAC) system. Filters containing 300 g of activated carbon per 0.09 m2 of filter face area were installed in two 'experimental' filter banks within an office building located in Sacramento, CA. The ozone removal performance of the filters was assessed through periodic measurements of ozone concentrations in the air upstream and downstream of the filters. Ozone concentrations were also measured upstream and downstream of a 'reference' filter bank containing filters without any activated carbon. The filter banks with prefilters containing activated carbon were removing 60percent to 70percent of the ozone 67 and 81 days after filter installation. In contrast, there was negligible ozone removal by the reference filter bank without activated carbon.

  18. Lithium Methyl Carbonate as a Reaction Product of Metallic Lithiumand Dimethyl Carbonate

    SciTech Connect

    Zhuang, Guorong V.; Yang, Hui; Ross Jr., Philip N.; Xu, Kang; Jow, T. Richard

    2005-10-16

    To improve the understanding of passive film formation on metallic lithium in organic electrolyte, we synthesized and characterized lithium methyl carbonate (LiOCO{sub 2}CH{sub 3}), a prototypical component of the film. The chemical structure of this compound was characterized with Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR), and its thermal stability and decomposition pathway was studied by thermo-gravimetric analysis (TGA). The FTIR spectrum of chemically synthesized compound enabled us to resolve multiple products in the passive film on lithium in dimethyl carbonate (DMC). Lithium methyl carbonate is only one of the components, the others being lithium oxalate and lithium methoxide.

  19. Carbon sink activity and GHG budget of managed European grasslands

    NASA Astrophysics Data System (ADS)

    Klumpp, Katja; Herfurth, Damien; Soussana, Jean-Francois; Fluxnet Grassland Pi's, European

    2013-04-01

    In agriculture, a large proportion (89%) of greenhouse gas (GHG) emission saving potential may be achieved by means of soil C sequestration. Recent demonstrations of carbon sink activities of European ecosystemes, however, often questioned the existence of C storing grasslands, as though a net sink of C was observed, uncertainty surrounding this estimate was larger than the sink itself (Janssens et al., 2003, Schulze et al., 2009. Then again, some of these estimates were based on a small number of measurements, and on models. Not surprising, there is still, a paucity of studies demonstrating the existence of grassland systems, where C sequestration would exceed (in CO2 equivalents) methane emissions from the enteric fermentation of ruminants and nitrous oxide emissions from managed soils. Grasslands are heavily relied upon for food and forage production. A key component of the carbon sink activity in grasslands is thus the impact of changes in management practices or effects of past and recent management, such as intensification as well as climate (and -variation). We analysed data (i.e. flux, ecological, management and soil organic carbon) from a network of European grassland flux observation sites (36). These sites covered different types and intensities of management, and offered the opportunity to understand grassland carbon cycling and trade-offs between C sinks and CH4 and N2O emissions. For some sites, the assessment of carbon sink activities were compared using two methods; repeated soil inventory and determination of the ecosystem C budget by continuous measurement of CO2 exchange in combination with quantification of other C imports and exports (net C storage, NCS). In general grassland, were a potential sink of C with 60±12 g C /m2.yr (median; min -456; max 645). Grazed sites had a higher NCS compared to cut sites (median 99 vs 67 g C /m2.yr), while permanent grassland sites tended to have a lower NCS compared to temporary sown grasslands (median 64 vs 125 g C /m2.yr). Including CH4 and N2O emission in the budget , revealed that for most sites, GHG emissions were compensated by NCS. The role of management impact,soil organic C and fluxes driven by interannual climate variation will be dicussed in the presentation.

  20. Reduction of iron(III) ion by activated carbon fiber

    SciTech Connect

    Uchida, M.; Shinohara, O.; Ito, S.; Kawasaki, N.; Nakamura, T.; Tanada, S.

    2000-04-15

    The mechanisms of adsorption of iron(II) ion, iron(III) ion, and reduced iron(III) ion onto an activated carbon fiber and the ability of carbon fibers to reduce iron(III) ion were investigated on the basis of the amounts of iron ion adsorbed. The amount of iron(II) ion adsorbed onto the activated carbon fiber increased with increasing adsorption temperature. Iron(II) ion was more easily removed by the activated carbon fiber than iron(III) ion. Iron(III) ion was adsorbed onto the activated carbon fiber after being reduced to iron(II) ion. The reduction ability of A-20 was stronger than that of A-10 because the hydrophilic groups of A-20 were larger than those of A-10. It is concluded that the activated carbon fiber has a reduction effect on iron(III) ion and that the reduction effect of the activated carbon fiber depended on the number of hydrophilic groups on the activated carbon fiber.

  1. Productive Activities and Aging Well.

    ERIC Educational Resources Information Center

    Herzog, A. Regula; House, James S.

    1991-01-01

    Older adults contribute to society through volunteer work, informal assistance, paid work, and self-care. Both individual and societal aging could benefit from increased productive participation of older persons, but institutions must provide more flexible options for them. (SK)

  2. Labile carbon concentrations are strongly linked to plant production in Arctic tussock tundra soils

    NASA Astrophysics Data System (ADS)

    Darrouzet-Nardi, A.; Weintraub, M. N.; Euskirchen, E. S.; Steltzer, H.; Sullivan, P.

    2013-12-01

    The exchange of carbon and nutrients between plants and microbes is a key determinant of carbon balance in Arctic soils. Microbes rely on labile plant carbon for the energy they need to produce enzymes that can release nutrients and less energetically favorable carbon from soil organic matter. One of the main mechanisms of carbon transfer is rhizodeposition, the exudation of labile plant carbon such as sugars from roots into the rhizosphere. Despite the importance of this flow of energy and materials from plants to microbes, there have been few attempts to quantify labile carbon pools or fluxes in Arctic soils. To improve our knowledge of labile carbon dynamics in Arctic soils, we address two basic questions: (1) What are the seasonal patterns of labile carbon concentrations? and (2) How do seasonal patterns in labile carbon correlate with plant production, microbial biomass, and soil nutrients? We measured concentrations of total reducing sugars (TRS) in the soil solution of moist acidic tussock tundra on 28 dates during the 2012 growing season in 20 plots of an early snowmelt warming experiment. We evaluated these total reducing sugar concentrations in the context of eddy flux carbon exchange data, plant NDVI, total dissolved carbon in soils, microbial biomass, and soil nutrients. Though we did not see treatment effects of the snowmelt warming experiment, we did observe a clear seasonal pattern in TRS concentrations in which they started low at the time of thaw, then built to a maximum value around the time of peak plant physiology in July, followed by a decline as plants senesced. We observed a clear correlation between TRS and gross primary production (GPP). NDVI values also increased with TRS concentrations during the first half of the season and then leveled off as TRS began its decline. These relationships were in contrast to labile N concentrations, which remained at low concentrations all season. Our data suggest that rhizodeposition of labile carbon compounds in Arctic tundra ecosystems has a strong seasonal pattern that closely tracks plant production. This connection suggests that if plant production increases in a warmer Arctic, plants may ease carbon limitation to summer microbial activity.

  3. Method for creating high carbon content products from biomass oil

    DOEpatents

    Parker, Reginald; Seames, Wayne

    2012-12-18

    In a method for producing high carbon content products from biomass, a biomass oil is added to a cracking reactor vessel. The biomass oil is heated to a temperature ranging from about 100.degree. C. to about 800.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to crack the biomass oil. Tar is separated from the cracked biomass oil. The tar is heated to a temperature ranging from about 200.degree. C. to about 1500.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to reduce the tar to a high carbon content product containing at least about 50% carbon by weight.

  4. Phenol removal onto novel activated carbons made from lignocellulosic precursors: influence of surface properties.

    PubMed

    Nabais, J M Valente; Gomes, J A; Suhas; Carrott, P J M; Laginhas, C; Roman, S

    2009-08-15

    The adsorption of phenol from dilute aqueous solutions onto new activated carbons (AC) was studied. The novel activated carbon was produced from lignocellulosic (LC) precursors of rapeseed and kenaf. Samples oxidised with nitric acid in liquid phase were also studied. The results have shown the significant potential of rapeseed and kenaf for the activated carbon production. The activated carbons produced by carbon dioxide activation were mainly microporous with BET apparent surface area up to 1350 m(2)g(-1) and pore volume 0.5 cm(3)g(-1). The effects of concentration (0.1-2 mM) and pH (3-13) were studied. The phenol adsorption isotherms at 25 degrees C followed the Freundlich model with maximum adsorption capacities of approximately 80 and 50 mg g(-1) for the pristine and oxidised activated carbons, respectively. The influence of pH on the adsorption has two trends for pH below and above 10. It was possible to conclude that when phenol is predominantly in the molecular form the most probable mechanism is based on the pi-pi dispersion interaction between the phenol aromatic ring and the delocalised pi electrons present in the activated carbon aromatic structure. When phenolate is the major component the electrostatic repulsion that occurs at high pH values is the most important aspect of the adsorption mechanism. PMID:19233559

  5. PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS

    SciTech Connect

    Dady Dadyburjor; Chong Chen; Elliot B. Kennel; Liviu Magean; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

    2005-12-12

    High melting temperature synthetic pitches (Synpitches) were created using coal derivatives produced from a solvent extraction technique. Solvent extraction is used to separate hydrocarbons from mineral matter as well as other insolubles. Mild hydrogenation can be used to chemically modify resultant material to produce a true pitch. There are three main techniques which can be used to tailor the softening point of the Synpitch. First, the softening point can be controlled by varying the conditions of hydrogenation, chiefly the temperature, pressure and residence time in a hydrogen overpressure. Second, by selectively distilling light hydrocarbons, the softening point of the remaining pitch can be raised. Third, the Synpitch can be blended with another mutually soluble pitch or hydrocarbon liquid. Through such techniques, spinnable isotropic Synpitches have been created from coal feedstocks. Characteristics of Synpitches include high cross-linking reactivity and high molecular weight, resulting in carbon fibers with excellent mechanical properties. To date, mechanical properties have been achieved which are comparable to the state of the art achievable with conventional coal tar pitch or petroleum pitch.

  6. CROP MANAGEMENT EFFECTS ON PRODUCTIVITY, SOIL NITROGEN, AND SOIL CARBON

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the influence of soil fertility on soil organic carbon (SOC) sequestration and nitrate-nitrogen (NO3-N) leaching potential under irrigated continuous corn production in northwest Texas. Research has indicated that a fertility program that maximizes crop yields will also have positive ...

  7. CONSERVATION ROTATIONS FOR COTTON PRODUCTION AND CARBON STORAGE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We conducted a 4-yr study on a Compass loamy sand (Plinthic Paleudult) to compare economics and soil organic carbon (SOC) storage of an intensive cropping system to standard cotton production systems in the Southeast. The system uses sunn hemp (Crotalaria juncea L.) and ultra-narrow row (UNR; 8-inc...

  8. Field windbreaks for bioenergy production and carbon sequestration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tree windbreaks are a multi-benefit land use with the ability to mitigate climate change by modifying the local microclimate for improved crop growth and sequestering carbon in soil and biomass. Agroforestry practices are also being considered for bioenergy production by direct combustion or produci...

  9. Laser-Induced Production of Large Carbon-Based Toriods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report on the production of large carbon-based toroids (CBTs) from fullerencs. The process involves two step laser irradiation of a mixed fullcrene target (76% C-60, 22% C-70). Transmission electron microscopy (11M) clearly identifies toroidal-shaped structures as well as Q-shaped constructs. ...

  10. Methodology for calculation of carbon balances for biofuel crops production

    NASA Astrophysics Data System (ADS)

    Gerlfand, I.; Hamilton, S. K.; Snapp, S. S.; Robertson, G. P.

    2012-04-01

    Understanding the carbon balance implications for different biofuel crop production systems is important for the development of decision making tools and policies. We present here a detailed methodology for assessing carbon balances in agricultural and natural ecosystems. We use 20 years of data from Long-term Ecological Research (LTER) experiments at the Kellogg Biological Station (KBS), combined with models to produce farm level CO2 balances for different management practices. We compared four grain and one forage systems in the U.S. Midwest: corn (Zea mays) - soybean (Glycine max) - wheat (Triticum aestivum) rotations managed with (1) conventional tillage, (2) no till, (3) low chemical input, and (4) biologically-based (organic) practices; and (5) continuous alfalfa (Medicago sativa). In addition we use an abandoned agricultural field (successionnal ecosystem) as reference system. Measurements include fluxes of N2O and CH4, soil organic carbon change, agricultural yields, and agricultural inputs (e.g. fertilization and farm fuel use). In addition to measurements, we model carbon offsets associated with the use of bioenergy from agriculturally produced crops. Our analysis shows the importance of establishing appropriate system boundaries for carbon balance calculations. We explore how different assumptions regarding production methods and emission factors affect overall conclusions on carbon balances of different agricultural systems. Our results show management practices that have major the most important effects on carbon balances. Overall, agricultural management with conventional tillage was found to be a net CO2 source to the atmosphere, while agricultural management under reduced tillage, low input, or organic management sequestered carbon at rates of 93, -23, -51, and -14 g CO2e m-2 yr-1, respectively for conventionally tilled, no-till, low-input, and organically managed ecosystems. Perennial systems (alfalfa and the successionnal fields) showed net carbon sequestration of -44 and -382 g CO2e m-2 yr-1, respectively. When studied systems were assumed to be used for bioenergy production, all system exhibited carbon sequestration -- between -149 and -841 g CO2e m-2 yr-1, for conventionally tilled and successionnal ecosystems, respectively.

  11. Adsorption uptake of synthetic organic chemicals by carbon nanotubes and activated carbons

    NASA Astrophysics Data System (ADS)

    Brooks, A. J.; Lim, Hyung-nam; Kilduff, James E.

    2012-07-01

    Carbon nanotubes (CNTs) have shown great promise as high performance materials for adsorbing priority pollutants from water and wastewater. This study compared uptake of two contaminants of interest in drinking water treatment (atrazine and trichloroethylene) by nine different types of carbonaceous adsorbents: three different types of single walled carbon nanotubes (SWNTs), three different sized multi-walled nanotubes (MWNTs), two granular activated carbons (GACs) and a powdered activated carbon (PAC). On a mass basis, the activated carbons exhibited the highest uptake, followed by SWNTs and MWNTs. However, metallic impurities in SWNTs and multiple walls in MWNTs contribute to adsorbent mass but do not contribute commensurate adsorption sites. Therefore, when uptake was normalized by purity (carbon content) and surface area (instead of mass), the isotherms collapsed and much of the CNT data was comparable to the activated carbons, indicating that these two characteristics drive much of the observed differences between activated carbons and CNT materials. For the limited data set here, the Raman D:G ratio as a measure of disordered non-nanotube graphitic components was not a good predictor of adsorption from solution. Uptake of atrazine by MWNTs having a range of lengths and diameters was comparable and their Freundlich isotherms were statistically similar, and we found no impact of solution pH on the adsorption of either atrazine or trichloroethylene in the range of naturally occurring surface water (pH = 5.7-8.3). Experiments were performed using a suite of model aromatic compounds having a range of ?-electron energy to investigate the role of ?-? electron donor-acceptor interactions on organic compound uptake by SWNTs. For the compounds studied, hydrophobic interactions were the dominant mechanism in the uptake by both SWNTs and activated carbon. However, comparing the uptake of naphthalene and phenanthrene by activated carbon and SWNTs, size exclusion effects appear to be more pronounced with activated carbon materials, perhaps due to smaller pore sizes or larger adsorption surface areas in small pores.

  12. Combined hydrogen production and storage with subsequent carbon crystallization.

    PubMed

    Lueking, Angela D; Gutierrez, Humberto R; Fonseca, Dania A; Narayanan, Deepa L; Van Essendelft, Dirk; Jain, Puja; Clifford, Caroline E B

    2006-06-21

    We provide evidence of low-temperature hydrogen evolution and possible hydrogen trapping in an anthracite coal derivative, formed via reactive ball milling with cyclohexene. No molecular hydrogen is added to the process. Raman-active molecular hydrogen vibrations are apparent in samples at atmospheric conditions (300 K, 1 bar) for samples prepared 1 year previously and stored in ambient air. Hydrogen evolves slowly at room temperature and is accelerated upon sample heating, with a first increase in hydrogen evolution occurring at approximately 60 degrees C. Subsequent chemical modification leads to the observation of crystalline carbons, including nanocrystalline diamond surrounded by graphene ribbons, other sp2-sp3 transition regions, purely graphitic regions, and a previously unidentified crystalline carbon form surrounded by amorphous carbon. The combined evidence for hydrogen trapping and carbon crystallization suggests hydrogen-induced crystallization of the amorphous carbon materials, as metastable hydrogenated carbons formed via the high-energy milling process rearrange into more thermodynamically stable carbon forms and molecular hydrogen. PMID:16771488

  13. Carbon Nanotube Activities at NASA-Johnson Space Center

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivaram

    2006-01-01

    Research activities on carbon nanotubes at NASA-Johnson Space Center include production, purification, characterization and their applications for human space flight. In-situ diagnostics during nanotube production by laser oven process include collection of spatial and temporal data of passive emission and laser induced fluorescence from C2, C3 and Nickel atoms in the plume. Details of the results from the "parametric study" of the pulsed laser ablation process indicate the effect of production parameters including temperature, buffer gas, flow rate, pressure, and laser fluence. Improvement of the purity by a variety of steps in the purification process is monitored by characterization techniques including SEM, TEM, Raman, UV-VIS-NIR and TGA. A recently established NASA-JSC protocol for SWCNT characterization is undergoing revision with feedback from nanotube community. Efforts at JSC over the past five years in composites have centered on structural polymednanotube systems. Recent activities broadened this focus to multifunctional materials, supercapacitors, fuel cells, regenerable CO2 absorbers, electromagnetic shielding, radiation dosimetry and thermal management systems of interest for human space flight. Preliminary tests indicate improvement of performance in most of these applications because of the large surface area as well as high electrical and thermal conductivity exhibited by SWCNTs.

  14. Adsorbed natural gas storage with activated carbons made from Illinois coals and scrap tires

    USGS Publications Warehouse

    Sun, Jielun; Brady, T.A.; Rood, M.J.; Lehmann, C.M.; Rostam-Abadi, M.; Lizzio, A.A.

    1997-01-01

    Activated carbons for natural gas storage were produced from Illinois bituminous coals (IBC-102 and IBC-106) and scrap tires by physical activation with steam or CO2 and by chemical activation with KOH, H3PO4, or ZnCl2. The products were characterized for N2-BET area, micropore volume, bulk density, pore size distribution, and volumetric methane storage capacity (Vm/Vs). Vm/Vs values for Illinois coal-derived carbons ranged from 54 to 83 cm3/cm3, which are 35-55% of a target value of 150 cm3/cm3. Both granular and pelletized carbons made with preoxidized Illinois coal gave higher micropore volumes and larger Vm/Vs values than those made without preoxidation. This confirmed that preoxidation is a desirable step in the production of carbons from caking materials. Pelletization of preoxidized IBC-106 coal, followed by steam activation, resulted in the highest Vm/Vs value. With roughly the same micropore volume, pelletization alone increased Vm/Vs of coal carbon by 10%. Tire-derived carbons had Vm/Vs values ranging from 44 to 53 cm3/cm3, lower than those of coal carbons due to their lower bulk densities. Pelletization of the tire carbons increased bulk density up to 160%. However, this increase was offset by a decrease in micropore volume of the pelletized materials, presumably due to the pellet binder. As a result, Vm/Vs values were about the same for granular and pelletized tire carbons. Compared with coal carbons, tire carbons had a higher percentage of mesopores and macropores.

  15. Adsorption of radon and water vapor on commercial activated carbons

    SciTech Connect

    Hassan, N.M.; Ghosh, T.K.; Hines, A.L.; Loyalka, S.K.

    1995-02-01

    Equilibrium adsorption isotherms are reported for radon and water vapor on two commercial activated carbons: coconut shell Type PCB and hardwood Type BD. The isotherms of the water vapor were measured gravimetrically at 298 K. The isotherms of radon from dry nitrogen were obtained at 293, 298, and 308 K while the data for the mixture of radon and water vapor were measured at 298 K. The concentrations of radon in the gas and solid phases were measured simultaneously, once the adsorption equilibrium and the radioactive equilibrium between the radon and its daughter products were established. The shape of the isotherms was of Type III for the radon and Type V for the water vapor, according to Brunauer`s classification. The adsorption mechanism was similar for both the radon and the water vapor, being physical adsorption on the macropore surface area in the low pressure region and micropore filling near saturation pressure. The uptake capacity of radon decreased both with increasing temperature and relative humidity. The heat of adsorption data indicated that the PCB- and the BD-activated carbons provided a heterogeneous surface for radon adsorption. The equilibrium data for radon were correlated with a modified Freundlich equation.

  16. Preparation of activated carbon monolith by application of phenolic resins as carbon precursors

    NASA Astrophysics Data System (ADS)

    Sajad, Mehran; Kazemzad, Mahmood; Hosseinnia, Azarmidokht

    2014-04-01

    In the current work, activated carbon monoliths have been prepared by application of different phenolic hydrocarbons namely catechol and resorcinol as carbon precursors. For synthesis of carbon monolith, the precursors have been mixed with Genapol PF-10 as template and then polymerized in the presence of lysine as catalyst. Then the polymerized monolith carbonized in inert atmosphere at 700C and activated by water steam at 550C. It was found that resorcinol polymerization is easier than catechol and occurred at 90C while for polymerization of catechol elevated temperature of 120C at hydrothermal condition is necessary. The prepared activated carbon samples have been characterized by various analysis methods including scanning electron microscopy (SEM), surface area measurement, and transmission electron microscopy (TEM). The adsorptions of three different aromatic hydrocarbons by the prepared activated carbon samples have also been investigated by high performance liquid chromatography (HPLC) and UV-Vis spectroscopy. It was found that carbon monolith prepared by catechol as carbon precursor has higher adsorpability and strength in comparison with the other sample. The higher performance of carbon monolith prepared by catechol can be associated with its higher active sites in comparison with resorcinol.

  17. Grain-based activated carbons for natural gas storage.

    PubMed

    Zhang, Tengyan; Walawender, Walter P; Fan, L T

    2010-03-01

    Natural gas has emerged as a potential alternative to gasoline due to the increase in global energy demand and environmental concerns. An investigation was undertaken to explore the technical feasibility of implementing the adsorbed natural gas (ANG) storage in the fuel tanks of motor vehicles with activated carbons from biomass, e.g., sorghum and wheat. The grain-based activated carbons were prepared by chemical activation; the experimental parameters were varied to identify the optimum conditions. The porosity of the resultant activated carbons was evaluated through nitrogen adsorption; and the storage capacity, through methane adsorption. A comparative study was also carried out with commercial activated carbons from charcoal. The highest storage factor attained was 89 for compacted grain-based activated carbons from grain sorghum with a bulk density of 0.65 g/cm(3), and the highest storage factor attained is 106 for compacted commercial activated carbons (Calgon) with a bulk density of 0.70 g/cm(3). The storage factor was found to increase approximately linearly with increasing bulk density and to be independent of the extent of compaction. This implies that the grain-based activated carbons are the ideal candidates for the ANG storage. PMID:19945864

  18. Morphogenesis and production of enzymes by Penicillium echinulatum in response to different carbon sources.

    PubMed

    Schneider, Willian Daniel Hahn; dos Reis, Lasa; Camassola, Marli; Dillon, Aldo Jos Pinheiro

    2014-01-01

    The effect of different carbon sources on morphology and cellulase and xylanase production of Penicillium echinulatum was evaluated in this work. Among the six carbon sources studied, cellulose and sugar cane bagasse were the most suitable for the production of filter paper activity, endoglucanases, xylanases, and ?-glucosidases. However, sucrose and glucose showed ? -glucosidase activities similar to those obtained with the insoluble sources. The polyacrylamide gels proved the enzymatic activity, since different standards bands were detected in the media mentioned above. Regarding morphology, it was observed that the mycelium in a dispersed form provided the greatest enzymatic activity, possibly due to greater interaction between the substrate and hyphae. These data are important in understanding the physiology of fungi and could contribute to obtaining enzyme with potential application in the technology of second generation ethanol. PMID:24877074

  19. Morphogenesis and Production of Enzymes by Penicillium echinulatum in Response to Different Carbon Sources

    PubMed Central

    Schneider, Willian Daniel Hahn; dos Reis, Laísa; Dillon, Aldo José Pinheiro

    2014-01-01

    The effect of different carbon sources on morphology and cellulase and xylanase production of Penicillium echinulatum was evaluated in this work. Among the six carbon sources studied, cellulose and sugar cane bagasse were the most suitable for the production of filter paper activity, endoglucanases, xylanases, and β-glucosidases. However, sucrose and glucose showed β-glucosidase activities similar to those obtained with the insoluble sources. The polyacrylamide gels proved the enzymatic activity, since different standards bands were detected in the media mentioned above. Regarding morphology, it was observed that the mycelium in a dispersed form provided the greatest enzymatic activity, possibly due to greater interaction between the substrate and hyphae. These data are important in understanding the physiology of fungi and could contribute to obtaining enzyme with potential application in the technology of second generation ethanol. PMID:24877074

  20. Comparison of adsorption characteristics for VOCs on acivated carbon and oxidized activated carbon

    SciTech Connect

    You, J.H.; Chiang, H.L.; Chiang, P.C. )

    1994-02-01

    In this investigation, the selected activated carbon is treated in NaOH solution or gas fluid with ozone from an ozone generator. FTIR, BET specific surface area and element analysis instruments were used to identify the difference in the chemical and physical characteristics between the activated carbon and oxidized activated carbon. The system of adsorption apparatus consists of a fixed adsorption column, quartz pan, electronic balance, and data acquisition system to measure the adsorption capacities and adsorption rates for VOCs under various operating conditions. VOCs n-hexane, methyl-ethyl-ketone, and benzene were selected to evaluate the effect of adsorption characterisitics on the activated carbon and oxidized activated carbon. The results of chemical analysis with the FTIR instrument indicate the adsorption bands and peaks measured at 1632 cm[sup [minus]1] on the oxidized activated carbons (AOHO[sub 3] and AO[sub 3]) are much stronger than on the activated carbon (AC). This shows that carbonyl (conjugated C=O) of the functional group is predominantly found to increase on the oxidized activated carbons (AO[sub 3] and AOHO[sub 3]). Significant changes were observed for BET-specific areas for AOHO[sub 3] and AO[sub 3] but the carbon contents of AOHO[sub 3] and AO[sub 3] decreases slightly. Moreover, the oxidized activated carbons showed greater affinity for polar adsorbate than did AC, and the overall effective mass transfer coefficients, k[sub D], of AO[sub 3] for various VOC adsorption were larger than those of AC and AOHO[sub 3]. 12 refs., 8 figs., 4 tabs.

  1. Thermoascus aurantiacus CBHI/Cel7A Production in Trichoderma reesei on Alternative Carbon Sources

    NASA Astrophysics Data System (ADS)

    Benk?, Zsuzsa; Drahos, Eszter; Szengyel, Zsolt; Puranen, Terhi; Vehmaanper, Jari; Rczey, Kati

    To develop functional enzymes in cellulose hydrolysis at or above 70C the cellobiohydrolase (CBHI/Cel7A) of Thermoascus aurantiacus was cloned and expressed in Trichoderma reesei Rut-C30 under the strong cbh1 promoter. Cellulase production of the parental strain and the novel strain (RF6026) was examined in submerged fermentation experiments using various carbon sources, which were lactose, Solka Floc 200 cellulose powder, and steam pretreated corn stover. An industrially feasible production medium was used containing only distiller's spent grain, KH2PO4, and (NH4)2SO4. Enzyme production was followed by measurements of protein concentration, total cellulase enzyme activity (filter paper activity), ?-glucosidase activity, CBHI activity, and endogenase I (EGI) activity. The Thermoascus CBHI/Cel7A activity was taken as an indication of the heterologous gene expression under the cbh1 promoter.

  2. Biogenic carbon fluxes from global agricultural production and consumption

    SciTech Connect

    Wolf, Julie; West, Tristram O.; Le Page, Yannick LB; Kyle, G. Page; Zhang, Xuesong; Collatz, George; Imhoff, Marc L.

    2015-10-01

    Quantification of biogenic carbon fluxes from agricultural lands is needed to generate comprehensive bottom-up estimates of net carbon exchange for global and regional carbon monitoring. We estimated global agricultural carbon fluxes associated with annual crop net primary production (NPP), harvested biomass, and consumption of biomass by humans and livestock. These estimates were combined for a single estimate of net carbon exchange (NCE) and spatially distributed to 0.05 degree resolution using MODIS satellite land cover data. Global crop NPP in 2011 was estimated at 5.25 ± 0.46 Pg C yr-1, of which 2.05 ± 0.05 Pg C yr-1 was harvested and 0.54 Pg C yr-1 was collected from crop residues for livestock fodder. Total livestock feed intake in 2011 was 2.42 ± 0.21 Pg C yr-1, of which 2.31 ± 0.21 Pg C yr-1 was emitted as CO2, 0.07 ± 0.01 Pg C yr-1 was emitted as CH4, and 0.04 Pg C yr-1 was contained within milk and egg production. Livestock grazed an estimated 1.27 Pg C yr-1 in 2011, which constituted 52.4% of total feed intake. Global human food intake was 0.57 ± 0.03 Pg C yr-1 in 2011, the majority of which is respired as CO2. Completed global cropland carbon budgets accounted for the ultimate use of ca. 80% of harvested biomass. The spatial distribution of these fluxes may be used for global carbon monitoring, estimation of regional uncertainty, and for use as input to Earth system models.

  3. Biogenic carbon fluxes from global agricultural production and consumption

    NASA Astrophysics Data System (ADS)

    Wolf, Julie; West, Tristram O.; Le Page, Yannick; Kyle, G. Page; Zhang, Xuesong; Collatz, G. James; Imhoff, Marc L.

    2015-10-01

    Quantification of biogenic carbon fluxes from agricultural lands is needed to generate comprehensive bottom-up estimates of net carbon exchange for global and regional carbon monitoring. We estimated global agricultural carbon fluxes associated with annual crop net primary production (NPP), harvested biomass, and consumption of biomass by humans and livestock. These estimates were combined for a single estimate of net carbon exchange and spatially distributed to 0.05° resolution using Moderate Resolution Imaging Spectroradiometer satellite land cover data. Global crop NPP in 2011 was estimated at 5.25 ± 0.46 Pg C yr-1, of which 2.05 ± 0.05 Pg C yr-1 was harvested and 0.54 Pg C yr-1 was collected from crop residues for livestock fodder. Total livestock feed intake in 2011 was 2.42 ± 0.21 Pg C yr-1, of which 2.31 ± 0.21 Pg C yr-1 was emitted as CO2, 0.07 ± 0.01 Pg C yr-1 was emitted as CH4, and 0.04 Pg C yr-1 was contained within milk and egg production. Livestock grazed an estimated 1.27 Pg C yr-1 in 2011, which constituted 52.4% of total feed intake. Global human food intake was 0.57 ± 0.03 Pg C yr-1 in 2011, the majority of which was respired as CO2. Completed global cropland carbon budgets accounted for the ultimate use of approximately 80% of harvested biomass. The spatial distribution of these fluxes may be used for global carbon monitoring, estimation of regional uncertainty, and for use as input to Earth system models.

  4. The nature of the products of deprotonation of disulfonyl carbon acids in acetonitrile solvent

    NASA Astrophysics Data System (ADS)

    Binkowska, I.; Jarczewski, A.

    2006-09-01

    The series of bis(ethylsulfonyl) and bis(benzylsulfonyl) activated carbon acids were synthesized and the products of the deprotonation of these carbon acids by strong, organic, cyclic bases such as: 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD) in acetonitrile were characterized by conductance measurements. The values of p Ka in acetonitrile are in the range between 19.1 and 24.23 for disulfonyl carbon acids and 25.96 and 25.0 for TBD and MTBD appropriately. The conductometric titration of 0.001 M carbon acids solution in acetonitrile with 0.1 M TBD or 0.1 M MTBD in acetonitrile has been carried out. The dissociation constant values of the products of the reaction between studied carbon acids and TBD and MTBD bases in acetonitrile at 25 °C have been estimated. The results of the conductometric study for various disulfonyl carbon acids indicate convincingly that the products of the studied proton transfer reactions in acetonitrile occur as free ions or can exist also in the form of ion pairs in case of phenyl[bis(ethylsulfonyl)]methane.

  5. Can we afford to waste carbon dioxide? Carbon dioxide as a valuable source of carbon for the production of light olefins.

    PubMed

    Centi, Gabriele; Iaquaniello, Gaetano; Perathoner, Siglinda

    2011-09-19

    Concerns about climate change have increased the amount of activity on carbon capture and sequestration (CCS) as one of the solutions to the problem of rising levels of CO(2) in the troposphere, while the reuse of CO(2) (carbon capture and recycling; CCR) has only recently received more attention. CCR is focused on the possibility of using CO(2) as a cheap (or even negative-value) raw material. This Concept paper analyzes this possibility from a different perspective: In a sustainable vision, can we afford to waste CO(2) as a source of carbon in a changing world faced with a fast depletion of natural carbon sources and in need of a low-carbon, resource-efficient economy? One of the points emerging from this discussion concerns the use of CO(2) for the production of olefins (substituting into or integrating with current energy-intensive methodologies that start from oil or syngas from other fossil fuel resources) if H(2) from renewable resources were available at competitive costs. This offers an opportunity to accelerate the introduction of renewable energy into the chemical production chain, and thus to improve resource efficiency in this important manufacturing sector. PMID:21922678

  6. Mechanisms of Carbon Nanotube Production by Laser Ablation Process

    NASA Technical Reports Server (NTRS)

    Scott, Carl D.; Arepalli, Sivaram; Nikolaev, Pavel; Smalley, Richard E.; Nocholson, Leonard S. (Technical Monitor)

    2000-01-01

    We will present possible mechanisms for nanotube production by laser oven process. Spectral emission of excited species during laser ablation of a composite graphite target is compared with that of laser irradiated C60 vapor. The similarities in the transient and spectral data suggest that fullerenes are intermediate precursors for nanotube formation. The confinement of the ablation products by means of a 25-mm diameter tube placed upstream of the target seems to improve the production and purity of nanotubes. Repeated laser pulses vaporize the amorphous/graphitic carbon and possibly catalyst particles, and dissociate fullerenes yielding additional feedstock for SWNT growth.

  7. Characteristics and humidity control capacity of activated carbon from bamboo.

    PubMed

    Horikawa, Toshihide; Kitakaze, Yoshiyuki; Sekida, Tomoki; Hayashi, Jun'ichi; Katoh, Masahiro

    2010-06-01

    Activated carbons were prepared from bamboo by chemical activation with K2CO3 or physical activation with CO2. The structural and surface chemical characteristics of the activated carbons were determined by N2 adsorption-desorption and Boehm titration, respectively. The water vapor adsorption properties of the activated carbons with various pore structures (preparation conditions) were examined. The relationship between water vapor adsorption capacity and pore properties, and the humidity control capacity of the prepared activated carbons are also discussed. The water adsorption isotherms show a region of rapidly increasing uptake of water vapor, and the relative humidity corresponding to those regions was different according to the preparation conditions, especially activation temperature. Water vapor adsorption capacity was improved with larger pore volume and surface area, but the humidity control capacity in a certain specific humidity region differed greatly according to the relative humidity corresponding to the steeply rising regions of the isotherms. In the typical operating conditions of an adsorption heat pump, RH 10-35%, the bamboo-sourced activated carbon that was prepared at 873K by potassium carbonate activation with impregnation ratio 1.0 had the highest humidity control capacity. PMID:20133125

  8. Production of biodiesel from carbon sources of macroalgae, Laminaria japonica.

    PubMed

    Xu, Xu; Kim, Ji Young; Oh, Yu Ri; Park, Jong Moon

    2014-10-01

    As aquatic biomass which is called "the third generation biomass", Laminaria japonica (also known as Saccharina japonica) consists of mannitol and alginate which are the main polysaccharides of algal carbohydrates. In this study, oleaginous yeast (Cryptococcus curvatus) was used to produce lipid from carbon sources derived from Laminaria japonica. Volatile fatty acids (VFAs) were produced by fermentation of alginate extracted from L. japonica. Thereafter, mannitol was mixed with VFAs to culture the oleaginous yeast. The highest lipid content was 48.30%. The composition of the fatty acids was similar to vegetable oils. This is the first confirmation of the feasibility of using macroalgae as a carbon source for biodiesel production. PMID:25084043

  9. Physicochemical and porosity characteristics of thermally regenerated activated carbon polluted with biological activated carbon process.

    PubMed

    Dong, Lihua; Liu, Wenjun; Jiang, Renfu; Wang, Zhansheng

    2014-11-01

    The characteristics of thermally regenerated activated carbon (AC) polluted with biological activated carbon (BAC) process were investigated. The results showed that the true micropore and sub-micropore volume, pH value, bulk density, and hardness of regenerated AC decreased compared to the virgin AC, but the total pore volume increased. XPS analysis displayed that the ash contents of Al, Si, and Ca in the regenerated AC respectively increased by 3.83%, 2.62% and 1.8%. FTIR spectrum showed that the surface functional groups of virgin and regenerated AC did not change significantly. Pore size distributions indicated that the AC regeneration process resulted in the decrease of micropore and macropore (D>10 μm) volume and the increase of mesopore and macropore (0.1 μm

  10. Liquid-phase adsorption of organic compounds by granular activated carbon and activated carbon fibers

    SciTech Connect

    Lin, S.H.; Hsu, F.M.

    1995-06-01

    Liquid-phase adsorption of organic compounds by granular activated carbon (GAC) and activated carbon fibers (ACFs) is investigated. Acetone, isopropyl alcohol (IPA), phenol, and tetrahydrofuran (THF) were employed as the model compounds for the present study. It is observed from the experimental results that adsorption of organic compounds by GAC and ACF is influenced by the BET (Brunauer-Emmett-Teller) surface area of adsorbent and the molecular weight, polarity, and solubility of the adsorbate. The adsorption characteristics of GAC and ACFs were found to differ rather significantly. In terms of the adsorption capacity of organic compounds, the time to reach equilibrium adsorption, and the time for complete desorption, ACFs have been observed to be considerably better than GAC. For the organic compounds tested here, the GAC adsorptions were shown to be represented well by the Langmuir isotherm while the ACF adsorption could be adequately described by the Langmuir or the Freundlich isotherm. Column adsorption tests indicated that the exhausted ACFs can be effectively regenerated by static in situ thermal desorption at 150 C, but the same regeneration conditions do not do as well for the exhausted GAC.

  11. The Late Miocene Carbon Isotope Shift and Marine Biological Productivity.

    NASA Astrophysics Data System (ADS)

    Diester-Haass, L.; Billups, K.; Emeis, K. C.

    2004-12-01

    The late Miocene global carbon isotope shift of approximately 1 per mil is not well understood. Is it linked to ocean-related processes such as the AƒAøAøâ_sA¬A.â_oBiologic BloomAƒAøAøâ_sA¬ \\(Farrell et al., 1995\\), or to changes in type \\(C3/C4 plants\\) or cover of terrestrial vegetation? Here we examine the evolution of marine biological productivity during the isotope shift at ODP Site 846 \\(Pacific equatorial upwelling, where the AƒAøAøâ_sA¬A.â_oBiologic BloomAƒAøAøâ_sA¬ has been first described, Farrell al, 1995\\) and at Indian Ocean Site 721 \\(monsoon-driven upwelling\\), and compare their productivity history with non upwelling locations in the Atlantic Ocean. The onset of the carbon isotope shift is accompanied at all locations by an increase in paleoproductivity derived from benthic foraminiferal accumulation rates \\(expressed as gC/cm2 * ky; Huerguera, 2000\\) and increased abundance of Uvigerina spp.. At the equatorial upwelling sites the increase is comparable to half present-day values to present-day values; in the Atlantic Ocean paleoproductivity increases from present-day up to 3 times present-day values. But the productivity maxima are not concurrent. The carbon isotope shift is accompanied by severe carbonate dissolution and reduced ventilation of bottom waters, as reflected in the occurrence of pyrite and good preservation of cartilageous fish debris. Carbonate preservation is good since about 6 Ma despite high productivity. We discuss changing deep water circulation patterns, increased weathering and continental nutrient delivery, as well as erosion of terrestrial vegetation as possible factors to explain our findings.

  12. Performance Evaluation of Activated Carbon Nanofiber as Carbon Supports to Improve the Cyclability of Li-Air Batteries.

    PubMed

    Park, Inyeong; Kim, Heeyun; Shim, Sang Eun; Baeck, Sung-Hyeon

    2015-11-01

    This study addresses the effects of the pore structures of carbon materials used as cathodes for non-aqueous lithium-air batteries on cycle life. Carbon Nanofibers (CNFs) were synthesized by electrospinning polyacrylonitrile (PAN) and carbonization. The synthesized CNF was then converted to activated carbon nanofibers (ACNFs) under flowing CO2. The specific surface areas CNFs were increased on activation. ACNFs were arranged randomly to form a web-like structure providing both oxygen pathways and a means of discharging products. To examine the electrochemical properties of ACNF, charge-discharge tests were conducted using a Swagelok-type cell at a constant current density of 0.2 mA/cm2; impedance tests were also conducted. ACNF sheet electrodes had cycle lives of up to 50 cycles, which was attributed to high surface area and porosity, although overpotentials for both charge and discharge were high. This cycling performance showed that the pore structure of sheet ACNF is more suitable for the transport of oxygen and for the storage of discharge products than carbon powders. PMID:26726643

  13. Preparation and electrochemical investigation of the cobalt hydroxide carbonate/activated carbon nanocomposite for supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Masikhwa, Tshifhiwa M.; Dangbegnon, Julien K.; Bello, Abdulhakeem; Madito, Moshawe J.; Momodu, Damilola; Manyala, Ncholu

    2016-01-01

    Cobalt hydroxide carbonate/activated carbon (AC) composite was successfully synthesized by hydrothermal method. Morphological characterizations of cobalt hydroxide carbonate/AC composite were carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the results show that the cobalt hydroxide carbonate nanorods are well dispersed on the AC. Due to the synergistic effects arising from cobalt hydroxide carbonate nanorods and AC, the electrochemical performances of pure cobalt hydroxide carbonate material is significantly improved by the addition of AC. The composite shows a specific capacitance of 301.44 F g-1 at a current density of 1 A g-1 in 6 M KOH electrolyte and exhibits good cycling stability. Based on the above results, the cobalt hydroxide carbonate/AC composite shows a considerable promise as electrode for electrochemical applications.

  14. Activated carbon fibers and engineered forms from renewable resources

    DOEpatents

    Baker, Frederick S

    2013-02-19

    A method of producing activated carbon fibers (ACFs) includes the steps of providing a natural carbonaceous precursor fiber material, blending the carbonaceous precursor material with a chemical activation agent to form chemical agent-impregnated precursor fibers, spinning the chemical agent-impregnated precursor material into fibers, and thermally treating the chemical agent-impregnated precursor fibers. The carbonaceous precursor material is both carbonized and activated to form ACFs in a single step. The method produces ACFs exclusive of a step to isolate an intermediate carbon fiber.

  15. Activated carbon fibers and engineered forms from renewable resources

    DOEpatents

    Baker, Frederick S.

    2010-06-01

    A method of producing activated carbon fibers (ACFs) includes the steps of providing a natural carbonaceous precursor fiber material, blending the carbonaceous precursor material with a chemical activation agent to form chemical agent-impregnated precursor fibers, spinning the chemical agent-impregnated precursor material into fibers, and thermally treating the chemical agent-impregnated precursor fibers. The carbonaceous precursor material is both carbonized and activated to form ACFs in a single step. The method produces ACFs exclusive of a step to isolate an intermediate carbon fiber.

  16. Preparation of activated carbons from agricultural residues for pesticide adsorption.

    PubMed

    Ioannidou, Ourania A; Zabaniotou, Anastasia A; Stavropoulos, George G; Islam, Md Azharul; Albanis, Triantafyllos A

    2010-09-01

    Activated carbons (ACs) can be used not only for liquid but also for vapour phase applications, such as water treatment, deodorisation, gas purification and air treatment. In the present study, activated carbons produced from agricultural residues (olive kernel, corn cobs, rapeseed stalks and soya stalks) via physical steam activation were tested for the removal of Bromopropylate (BP) from water. For the characterization of the activated carbons ICP, SEM, FTIR and XRD analyses were performed. Adsorption kinetics and equilibrium isotherms were investigated for all biomass activated carbons in aqueous solutions. Experimental data of BP adsorption have fitted best to the pseudo 2nd-order kinetic model and Langmuir isotherm. The study resulted that corn cobs showed better adsorption capacity than the other biomass ACs. Comparison among ACs from biomass and commercial ones (F400 and Norit GL50) revealed that the first can be equally effective for the removal of BP from water with the latter. PMID:20598734

  17. Extramitochondrial domain rich in carbonic anhydrase activity improves myocardial energetics.

    PubMed

    Schroeder, Marie A; Ali, Mohammad A; Hulikova, Alzbeta; Supuran, Claudiu T; Clarke, Kieran; Vaughan-Jones, Richard D; Tyler, Damian J; Swietach, Pawel

    2013-03-01

    CO2 is produced abundantly by cardiac mitochondria. Thus an efficient means for its venting is required to support metabolism. Carbonic anhydrase (CA) enzymes, expressed at various sites in ventricular myocytes, may affect mitochondrial CO2 clearance by catalyzing CO2 hydration (to H(+) and HCO3(-)), thereby changing the gradient for CO2 venting. Using fluorescent dyes to measure changes in pH arising from the intracellular hydration of extracellularly supplied CO2, overall CA activity in the cytoplasm of isolated ventricular myocytes was found to be modest (2.7-fold above spontaneous kinetics). Experiments on ventricular mitochondria demonstrated negligible intramitochondrial CA activity. CA activity was also investigated in intact hearts by (13)C magnetic resonance spectroscopy from the rate of H(13)CO3(-) production from (13)CO2 released specifically from mitochondria by pyruvate dehydrogenase-mediated metabolism of hyperpolarized [1-(13)C]pyruvate. CA activity measured upon [1-(13)C]pyruvate infusion was fourfold higher than the cytoplasm-averaged value. A fluorescent CA ligand colocalized with a mitochondrial marker, indicating that mitochondria are near a CA-rich domain. Based on immunoreactivity, this domain comprises the nominally cytoplasmic CA isoform CAII and sarcoplasmic reticulum-associated CAXIV. Inhibition of extramitochondrial CA activity acidified the matrix (as determined by fluorescence measurements in permeabilized myocytes and isolated mitochondria), impaired cardiac energetics (indexed by the phosphocreatine-to-ATP ratio measured by (31)P magnetic resonance spectroscopy of perfused hearts), and reduced contractility (as measured from the pressure developed in perfused hearts). These data provide evidence for a functional domain of high CA activity around mitochondria to support CO2 venting, particularly during elevated and fluctuating respiratory activity. Aberrant distribution of CA activity therefore may reduce the heart's energetic efficiency. PMID:23431149

  18. Microbial primary production on an Arctic glacier is insignificant in comparison with allochthonous organic carbon input.

    PubMed

    Stibal, Marek; Tranter, Martyn; Benning, Liane G; Rehk, Josef

    2008-08-01

    Cryoconite holes are unique freshwater environments on glacier surfaces, formed when solar-heated dark debris melts down into the ice. Active photoautotrophic microorganisms are abundant within the holes and fix inorganic carbon due to the availability of liquid water and solar radiation. Cryoconite holes are potentially important sources of organic carbon to the glacial ecosystem, but the relative magnitudes of autochthonous microbial primary production and wind-borne allochthonous organic matter brought are unknown. Here, we compare an estimate of annual microbial primary production in 2006 on Werenskioldbreen, a Svalbard glacier, with the organic carbon content of cryoconite debris. There is a great disparity between annual primary production (4.3 mug C g(-1) year(-1)) and the high content of organic carbon within the debris (1.7-4.5%, equivalent to 8500-22 000 mug C g(-1) debris). Long-term accumulation of autochthonous organic matter is considered unlikely due to ablation dynamics and the surface hydrology of the glacier. Rather, it is more likely that the majority of the organic matter on Werenskioldbreen is allochthonous. Hence, although glacier surfaces can be a significant source of organic carbon for glacial environments on Svalbard, they may be reservoirs rather than oases of high productivity. PMID:18430008

  19. Microstructure and surface properties of lignocellulosic-based activated carbons

    NASA Astrophysics Data System (ADS)

    Gonzlez-Garca, P.; Centeno, T. A.; Urones-Garrote, E.; vila-Brande, D.; Otero-Daz, L. C.

    2013-01-01

    Low cost activated carbons have been produced via chemical activation, by using KOH at 700 C, from the bamboo species Guadua Angustifolia and Bambusa Vulgaris Striata and the residues from shells of the fruits of Castanea Sativa and Juglans Regia as carbon precursors. The scanning electron microscopy micrographs show the conservation of the precursor shape in the case of the Guadua Angustifolia and Bambusa Vulgaris Striata activated carbons. Transmission electron microscopy analyses reveal that these materials consist of carbon platelet-like particles with variable length and thickness, formed by highly disordered graphene-like layers with sp2 content ? 95% and average mass density of 1.65 g/cm3 (25% below standard graphite). Textural parameters indicate a high porosity development with surface areas ranging from 850 to 1100 m2/g and average pore width centered in the supermicropores range (1.3-1.8 nm). The electrochemical performance of the activated carbons shows specific capacitance values at low current density (1 mA/cm2) as high as 161 F/g in the Juglans Regia activated carbon, as a result of its textural parameters and the presence of pseudocapacitance derived from surface oxygenated acidic groups (mainly quinones and ethers) identified in this activated carbon.

  20. Hydrogen storage on activated carbon. Final report

    SciTech Connect

    Schwarz, J.A.

    1994-11-01

    The project studied factors that influence the ability of carbon to store hydrogen and developed techniques to enhance that ability in naturally occurring and factory-produced commercial carbon materials. During testing of enhanced materials, levels of hydrogen storage were achieved that compare well with conventional forms of energy storage, including lead-acid batteries, gasoline, and diesel fuel. Using the best materials, an electric car with a modern fuel cell to convert the hydrogen directly to electricity would have a range of over 1,000 miles. This assumes that the total allowable weight of the fuel cell and carbon/hydrogen storage system is no greater than the present weight of batteries in an existing electric vehicle. By comparison, gasoline cars generally are limited to about a 450-mile range, and battery-electric cars to 40 to 60 miles. The project also developed a new class of carbon materials, based on polymers and other organic compounds, in which the best hydrogen-storing factors discovered earlier were {open_quotes}molecularly engineered{close_quotes} into the new materials. It is believed that these new molecularly engineered materials are likely to exceed the performance of the naturally occurring and manufactured carbons seen earlier with respect to hydrogen storage.

  1. Activated carbon testing for the 200 area effluent treatment facility

    SciTech Connect

    Wagner, R.N.

    1997-01-17

    This report documents pilot and laboratory scale testing of activated carbon for use in the 200 Area Effluent Treatment Facility peroxide decomposer columns. Recommendations are made concerning column operating conditions and hardware design, the optimum type of carbon for use in the plant, and possible further studies.

  2. ACTIVATED CARBON PROCESS FOR TREATMENT OF WASTEWATERS CONTAINING HEXAVALENT CHROMIUM

    EPA Science Inventory

    The removal of hexavalent chromium, Cr(VI), from dilute aqueous solution by an activated carbon process has been investigated. Two removal mechanisms were observed; hexavalent chromium species were removed by adsorption onto the interior carbon surface and/or through reduction to...

  3. DESIGN AND CONSTRUCTION OF A MOBILE ACTIVATED CARBON REGENERATOR SYSTEM

    EPA Science Inventory

    Activated carbon adsorption has become a standard procedure for the cleanup of contaminated water streams. To facilitate such cleanup at hazardous waste and spill sites, mobile carbon adsorption units have been constructed and are now in use. Their primary drawback is the logisti...

  4. HARDWOOD-BASED GRANULAR ACTIVATED CARBON FOR METALS REMEDIATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Granular activated carbon is usually the adsorbent of choice for removing organic pollutants from air and water waste streams. Its ability to remove metal ions from aqueous media is considered secondary to its ability to remove organics. Only recently was a coal-based, commerical carbon (Minotaur,...

  5. SYNTHETIC ORGANIC CHEMICAL REMOVAL BY GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    The paper is an overview of the adsorbability of synthetic organic chemicals (SOC) by granular activated carbon (GAC). The paper demonstrates the adsorbability by presenting data on the removal of SOCs and organic surrogates such as total organic carbon and total organic halide b...

  6. 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...

  7. HARDWOOD-BASED GRANULAR ACTIVATED CARBON FOR METALS REMEDIATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Granular activated carbon is usually the adsorbent of choice for removing organic pollutants from air and water waste streams. Its ability to remove metal ions from aqueous media is considered secondary to its ability to remove organics. Only recently was a coal-based, commercial carbon (Minotaur) m...

  8. HARDWOOD-BASED GRANULAR ACTIVATED CARBON FOR METALS REMEDIATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Granular activated carbon is usually the adsorbent of choice for removing organic pollutants from air and water waste streams. Its ability to remove metal ions from aqueous media is considered secondary to its ability to remove organics. Only recently was a coal-based, commercial carbon (Minotaur, C...

  9. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production

    SciTech Connect

    Zeikus, J.G.; Jain, M.K.

    1992-01-01

    This reporting period, progress is reported on the following: metabolic pathway of solvent production in B. methylotrophicum; the biochemical mechanism for metabolic regulation of the succinate fermentation; models to understand the physiobiochemical function of formate metabolism in anaerobes and; models for understanding the influence of low pH on one carbon metabolism. (CBS)

  10. Catalytic oxidation ofS(IV) on activated carbon in aqueous suspension: kinetics and mechanism

    SciTech Connect

    Brodzinsky, R.

    1981-02-01

    Activated carbon and combustion produced soot particles have been studied for their catalytic effect on the oxidation of aqueous sulfur(IV) species. Detailed kinetic studies of the reaction were performed on three different activated carbons and on a soot collected in a highway tunnel. Combustion produced soots were tested for their catalytic behavior and found to be similar to the activated carbons. The reaction rate was found to be linearly dependent on the concentration of carbon particles in the solution. The rate was found to follow a Langmuir adsorption isotherm for its dependence on oxygen and the product of two adsorption isotherms for S(IV). The reaction is independent of the pH of the solution when the pH is below 7.6. The reaction does not occur when the pH is above 7.6. The three aqueous S(IV) species are catalyzed in their oxidation by the carbon particles in a similar manner. Activation energies for the reactions on the different carbons are all about 8.5 kcal/mole. A possible four-step reaction mechanism is proposed. It consists of the adsorption of a dissolved oxygen molecule onto the carbon surface, followed by the adsorption of two S(IV) molecules or ions. These are oxidized on the surface to sulfate, which desorbs from the surface, regenerating the catalytically active site.

  11. Silver Nanoparticle Impregnated Bio-Based Activated Carbon with Enhanced Antimicrobial Activity

    NASA Astrophysics Data System (ADS)

    Selvakumar, R.; Suriyaraj, S. P.; Jayavignesh, V.; Swaminathan, K.

    2013-08-01

    The present study involves the production of silver nanoparticles using a novel yeast strain Saccharomyces cerevisiae BU-MBT CY-1 isolated from coconut cell sap. The biological reduction of silver nitrate by the isolate was deducted at various time intervals. The yeast cells after biological silver reduction were harvested and subjected to carbonization at 400°C for 1 h and its properties were analyzed using Fourier transform infra-red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscopy. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells (CCY) did not contain any particles on its surface. The carbonized silver nanoparticles containing yeast cells (CSY) were made into bioactive emulsion and tested for its efficacy against various pathogenic Gram positive and Gram negative bacteria. The antimicrobial activity studies indicated that CSY bioactive nanoemulsion was effective against Gram negative organisms than Gram positive organism.

  12. Breakthrough CO2 adsorption in bio-based activated carbons.

    PubMed

    Shahkarami, Sepideh; Azargohar, Ramin; Dalai, Ajay K; Soltan, Jafar

    2015-08-01

    In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO2 activation and Potassium hydroxide (KOH) activation. CO2 adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25-65C and inlet CO2 concentration range of 10-30mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N2 and CO2 adsorption at 77 and 273K, respectively. Central composite design was used to evaluate the combined effects of temperature and concentration of CO2 on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62cm(3)/g and surface area of 1400m(2)/g had the highest CO2 adsorption capacity of 1.8mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30mol% CO2 and 25C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO2 activated carbons remained remarkably stable after 50cycles with low temperature (160C) regeneration. PMID:26257348

  13. TESTING GUIDELINES FOR TECHNETIUM-99 ABSORPTION ON ACTIVATED CARBON

    SciTech Connect

    BYRNES ME

    2010-09-08

    CH2M HILL Plateau Remediation Company (CHPRC) is currently evaluating the potential use of activated carbon adsorption for removing technetium-99 from groundwater as a treatment method for the Hanford Site's 200 West Area groundwater pump-and-treat system. The current pump-and-treat system design will include an ion-exchange (IX) system for selective removal of technetium-99 from selected wells prior to subsequent treatment of the water in the central treatment system. The IX resin selected for technetium-99 removal is Purolite A530E. The resin service life is estimated to be approximately 66.85 days at the design technetium-99 loading rate, and the spent resin must be replaced because it cannot be regenerated. The resulting operating costs associated with resin replacement every 66.85 days are estimated at $0.98 million/year. Activated carbon pre-treatment is being evaluated as a potential cost-saving measure to offset the high operating costs associated with frequent IX resin replacement. This document is preceded by the Literature Survey of Technetium-99 Groundwater Pre-Treatment Option Using Granular Activated Carbon (SGW-43928), which identified and evaluated prior research related to technetium-99 adsorption on activated carbon. The survey also evaluated potential operating considerations for this treatment approach for the 200 West Area. The preliminary conclusions of the literature survey are as follows: (1) Activated carbon can be used to selectively remove technetium-99 from contaminated groundwater. (2) Technetium-99 adsorption onto activated carbon is expected to vary significantly based on carbon types and operating conditions. For the treatment approach to be viable at the Hanford Site, activated carbon must be capable of achieving a designated minimum technetium-99 uptake. (3) Certain radionuclides known to be present in 200 West Area groundwater are also likely to adsorb onto activated carbon. (4) Organic solvent contaminants of concern (COCs) will load heavily onto activated carbon and should be removed from groundwater upstream of the activated carbon pre-treatment system. Unless removed upstream, the adsorbed loadings of these organic constituents could exceed the land disposal criteria for carbon.

  14. Selection and preparation of activated carbon for fuel gas storage

    DOEpatents

    Schwarz, James A. (Fayetteville, NY); Noh, Joong S. (Syracuse, NY); Agarwal, Rajiv K. (Las Vegas, NV)

    1990-10-02

    Increasing the surface acidity of active carbons can lead to an increase in capacity for hydrogen adsorption. Increasing the surface basicity can facilitate methane adsorption. The treatment of carbons is most effective when the carbon source material is selected to have a low ash content i.e., below about 3%, and where the ash consists predominantly of alkali metals alkali earth, with only minimal amounts of transition metals and silicon. The carbon is washed in water or acid and then oxidized, e.g. in a stream of oxygen and an inert gas at an elevated temperature.

  15. Get the most from activated-carbon systems

    SciTech Connect

    Boppart, S.

    1995-05-01

    Many manufacturing operations use organic solvents that evaporate in the course of their transportation, storage and use. Adsorption systems using activated carbon have long been used to recover these airborne solvents and other organic vapors. Adsorption systems are an economical way to reclaim solvents for reuse. They are also an effective way to comply with pollution-control regulations that govern volatile organic compounds (VOCs) in industrial exhaust streams, and vapors collected during soil and site remediations. For most air-pollution-control applications, carbon is activated by subjecting the starting material to controlled charring in a kiln, extruding it into pellets and activating it with steam at roughly 1,000 C. During activation, the carbon pellets develop an intricate pore structure, which may have a total internal surface area of up to 1,500 m{sup 2}/g. It is this internal pore structure that gives activated carbon its purifying capacity. To recover solvents adsorbed on the carbon, energy must be applied to overcome the solvents` attraction to the pore surface. This is most commonly done by applying heat, by means of steam, hot inert gas or direct heating. Desorption can also be carried out by changing the equilibrium conditions, by applying a vacuum or purging the adsorbates from the carbon pores using a gas stream. The solvent vapors coming off the carbon will be concentrated, and can be condensed and recovered as a liquid.

  16. India's aluminum industry: Productivity, energy efficiency and carbon emissions

    SciTech Connect

    Schumacher, Katja; Sathaye, Jayant

    1999-07-01

    Historical estimates of productivity growth in India's aluminum sector vary from indicating an improvement to a decline in the sector's productivity. The variance may be traced to the time period of study, source of data for analysis, and type of indices and econometric specifications used for reporting productivity growth. An analysis shows that in the twenty year period, 1973 to 1993, productivity in the aluminum sector declined slightly by 0.2%. An econometric analysis reveals that technical progress in India's aluminum sector has been biased towards the use of energy, while it has been labor saving. The decline in productivity was mainly driven by a decline in the 1970s when capacity utilization was low and the energy crisis hit India and the world. From the early 1980s on productivity recuperated. The authors examine the current changes in structure and energy efficiency in the sector. Their analysis shows that the Indian aluminum sector has high potential to move towards world-best technology, which will result in fewer carbon emissions and more efficient energy use. Substantial energy savings and carbon reduction options exist.

  17. Carbon-based ocean productivity and phytoplankton physiology from space

    NASA Astrophysics Data System (ADS)

    Behrenfeld, Michael J.; Boss, Emmanuel; Siegel, David A.; Shea, Donald M.

    2005-03-01

    Ocean biogeochemical and ecosystem processes are linked by net primary production (NPP) in the ocean's surface layer, where inorganic carbon is fixed by photosynthetic processes. Determinations of NPP are necessarily a function of phytoplankton biomass and its physiological status, but the estimation of these two terms from space has remained an elusive target. Here we present new satellite ocean color observations of phytoplankton carbon (C) and chlorophyll (Chl) biomass and show that derived Chl:C ratios closely follow anticipated physiological dependencies on light, nutrients, and temperature. With this new information, global estimates of phytoplankton growth rates (μ) and carbon-based NPP are made for the first time. Compared to an earlier chlorophyll-based approach, our carbon-based values are considerably higher in tropical oceans, show greater seasonality at middle and high latitudes, and illustrate important differences in the formation and demise of regional algal blooms. This fusion of emerging concepts from the phycological and remote sensing disciplines has the potential to fundamentally change how we model and observe carbon cycling in the global oceans.

  18. DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS

    SciTech Connect

    Elliot B. Kennel; Stephen P. Carpenter; Dady Dadyburjor; Manoj Katakdaunde; Liviu Magean; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

    2005-08-11

    The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. These carbon products include materials used in metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. During this reporting period, efforts have focused on the facility modifications for continuous hydrotreating, as well as developing improved protocols for producing synthetic pitches.

  19. Sustainable Regeneration of Nanoparticle Enhanced Activated Carbon in Water

    EPA Science Inventory

    The regeneration and reuse of exhausted granular activated carbon (GAC) is an appropriate method for lowering operational and environmental costs. Advanced oxidation is a promising environmental friendly technique for GAC regeneration. The main objective of this research was to ...

  20. GRANULAR ACTIVATED CARBON ADSORPTION AND INFRARED REACTIVATION: A CASE STUDY

    EPA Science Inventory

    A study evaluated the effectiveness and cost of removing trace organic contaminants and surrogates from drinking water by granular activated carbon (GAC) adsorption. The effect of multiple reactivations of spent GAC was also evaluated. Results indicated that reactivated GAC eff...

  1. CREAT A CONSORTIUM AND DEVELOP PREMIUM CARBON PRODUCTS FROM COAL

    SciTech Connect

    John M. Andresen

    2003-08-01

    The Consortium for Premium Carbon Products from Coal, with funding from the U.S. Department of Energy's National Energy Technology Laboratory and matching funds from industry and academic institutions continued to excel in developing innovative technologies to use coal and coal-derived feedstocks to produce premium carbon product. During Budget Period 5, eleven projects were supported and sub-contracted were awarded to seven organizations. The CPCPC held two meetings and one tutorial at various locations during the year. Budget Period 5 was a time of growth for CPCPC in terms of number of proposals and funding requested from members, projects funded and participation during meetings. Although the membership was stable during the first part of Budget Period 5 an increase in new members was registered during the last months of the performance period.

  2. Environmental remediation and conversion of carbon dioxide (CO(2)) into useful green products by accelerated carbonation technology.

    PubMed

    Lim, Mihee; Han, Gi-Chun; Ahn, Ji-Whan; You, Kwang-Suk

    2010-01-01

    This paper reviews the application of carbonation technology to the environmental industry as a way of reducing carbon dioxide (CO(2)), a green house gas, including the presentation of related projects of our research group. An alternative technology to very slow natural carbonation is the co-called 'accelerated carbonation', which completes its fast reaction within few hours by using pure CO(2). Carbonation technology is widely applied to solidify or stabilize solid combustion residues from municipal solid wastes, paper mill wastes, etc. and contaminated soils, and to manufacture precipitated calcium carbonate (PCC). Carbonated products can be utilized as aggregates in the concrete industry and as alkaline fillers in the paper (or recycled paper) making industry. The quantity of captured CO(2) in carbonated products can be evaluated by measuring mass loss of heated samples by thermo-gravimetric (TG) analysis. The industrial carbonation technology could contribute to both reduction of CO(2) emissions and environmental remediation. PMID:20195442

  3. Adsorption of dichlorodifluoromethane, chlorodifluoromethane, and chloropentafluoroethane on activated carbon

    SciTech Connect

    Berlier, K.; Frere, M.; Bougard, J.

    1995-09-01

    The CFCs (chlorofluorocarbons) are used as working refrigerant fluids. Recent concerns of the effects of CFCs on the ozone layer requires the development of efficient recovery methods. One technique is to adsorb the fluids onto a porous medium such as silica gel or activated carbon. Isotherms and enthalpies of adsorption curves of dichlorodifluoromethane (R12), chlorodifluoromethane (R22), and chloropentafluoroethane (R115) on three different activated carbons have been obtained at 303 K and at pressures to 602 kPa.

  4. Preparation and characterization of activated carbon from sugarcane bagasse by physical activation with CO2 gas

    NASA Astrophysics Data System (ADS)

    Bachrun, Sutrisno; AyuRizka, Noni; Annisa, SolichaHidayat; Arif, Hidayat

    2016-01-01

    A series of experiments have been conducted to study the effects of different carbonization temperatures (400, 600, and 800oC) on characteristics of porosity in activated carbon derived from carbonized sugarcane bagassechar at activation temperature of 800oC. The results showed that the activated carbon derived from high carbonized temperature of sugarcane bagassechars had higher BET surface area, total volume, micropore volume and yield as compared to the activated carbon derived from low carbonized temperature. The BET surface area, total volume and micropore volume of activated carbon prepared from sugarcane bagassechars obtained at 800oC of carbonized temperature and activation time of 120 min were 661.46m2/g, 0.2455cm3/g and 0.1989cm3/g, respectively. The high carbonization temperature (800oC) generated a highly microporous carbonwith a Type-I nitrogen adsorption isotherm, while the low carbonization temperature (400 and 600oC) generated a mesoporous one with an intermediate between types I and IInitrogen adsorption isotherm.

  5. Carbon Nanotube Materials for Substrate Enhanced Control of Catalytic Activity

    SciTech Connect

    Heben, M.; Dillon, A. C.; Engtrakul, C.; Lee, S.-H.; Kelley, R. D.; Kini, A. M.

    2007-05-01

    Carbon SWNTs are attractive materials for supporting electrocatalysts. The properties of SWNTs are highly tunable and controlled by the nanotube's circumferential periodicity and their surface chemistry. These unique characteristics suggest that architectures constructed from these types of carbon support materials would exhibit interesting and useful properties. Here, we expect that the structure of the carbon nanotube support will play a major role in stabilizing metal electrocatalysts under extreme operating conditions and suppress both catalyst and support degradation. Furthermore, the chemical modification of the carbon nanotube surfaces can be expected to alter the interface between the catalyst and support, thus, enhancing the activity and utilization of the electrocatalysts. We plan to incorporate discrete reaction sites into the carbon nanotube lattice to create intimate electrical contacts with the catalyst particles to increase the metal catalyst activity and utilization. The work involves materials synthesis, design of electrode architectures on the nanoscale, control of the electronic, ionic, and mass fluxes, and use of advanced optical spectroscopy techniques.

  6. Activated carbon for aerobic oxidation: Benign approach toward 2-benzoylbenzimidazoles and 2-benzoylbenzoxazoles synthesis

    PubMed Central

    Bao, Kai; Li, Fuqing; Liu, Hanjing; Wang, Zhiwei; Shen, Qirong; Wang, Jian; Zhang, Weige

    2015-01-01

    A general strategy involving a novel and highly efficient aerobic benzylic oxidation promoted by cheap, reusable activated carbon in water is developed. Application of this method has been demonstrated in the benign synthesis of bioactive 2-benzoylbenzimidazoles and 2-benzoylbenzoxazoles derivatives. Furthermore, the activated carbon catalyst could be recovered and reused at least three times without significantly losing its activity. Preliminary research suggests that the oxidation mechanism may involve intermediate hydroperoxidation and that a portion of the final carbonyl product is obtained through a secondary benzylic alcohol intermediate. Finally, theoretical calculations reveal that the oxidation yield is closely associated with the electric density at the benzylic position of the substrate. PMID:26041483

  7. Estimation of the carbon footprint of the Galician fishing activity (NW Spain).

    PubMed

    Iribarren, Diego; Vzquez-Rowe, Ian; Hospido, Almudena; Moreira, Mara Teresa; Feijoo, Gumersindo

    2010-10-15

    The food production system as a whole is recognized as one of the major contributors to environmental impacts. Accordingly, food production, processing, transport and consumption account for a relevant portion of the greenhouse gas (GHG) emissions associated with any country. In this context, there is an increasing market demand for climate-relevant information regarding the global warming impact of consumer food products throughout the supply chains. This article deals with the assessment of the carbon footprint of seafood products as a key subgroup in the food sector. Galicia (NW Spain) was selected as a case study. The analysis is based on a representative set of species within the Galician fishing sector, including species obtained from coastal fishing (e.g. horse mackerel, Atlantic mackerel, European pilchard and blue whiting), offshore fishing (e.g. European hake, megrim and anglerfish), deep-sea fishing (skipjack and yellowfin tuna), extensive aquaculture (mussels) and intensive aquaculture (turbot). The carbon footprints associated with the production-related activities of each selected species were quantified following a business-to-business approach on the basis of 1year of fishing activity. These individual carbon footprints were used to calculate the carbon footprint for each of the different Galician fisheries and culture activities. Finally, the lump sum of the carbon footprints for coastal, offshore and deep-sea fishing and extensive and intensive aquaculture brought about the carbon footprint of the Galician fishing activity (i.e., capture and culture). A benchmark for quantifying and communicating emission reductions was then provided, and opportunities to reduce the GHG emissions associated with the Galician fishing activity could be prioritized. PMID:20800266

  8. Water vapor adsorption on activated carbon preadsorbed with naphtalene.

    PubMed

    Zimny, T; Finqueneisel, G; Cossarutto, L; Weber, J V

    2005-05-01

    The adsorption of water vapor on a microporous activated carbon derived from the carbonization of coconut shell has been studied. Preadsorption of naphthalene was used as a tool to determine the location and the influence of the primary adsorbing centers within the porous structure of active carbon. The adsorption was studied in the pressure range p/p0=0-0.95 in a static water vapor system, allowing the investigation of both kinetic and equilibrium experimental data. Modeling of the isotherms using the modified equation of Do and Do was applied to determine the effect of preadsorption on the mechanism of adsorption. PMID:15797395

  9. Activated carbon fiber composite material and method of making

    DOEpatents

    Burchell, Timothy D. (Oak Ridge, TN); Weaver, Charles E. (Knoxville, TN); Chilcoat, Bill R. (Knoxville, TN); Derbyshire, Frank (Lexington, KY); Jagtoyen, Marit (Lexington, KY)

    2001-01-01

    An activated carbon fiber composite for separation and purification, or catalytic processing of fluids is described. The activated composite comprises carbon fibers rigidly bonded to form an open, permeable, rigid monolith capable of being formed to near-net-shape. Separation and purification of gases are effected by means of a controlled pore structure that is developed in the carbon fibers contained in the composite. The open, permeable structure allows the free flow of gases through the monolith accompanied by high rates of adsorption. By modification of the pore structure and bulk density the composite can be rendered suitable for applications such as gas storage, catalysis, and liquid phase processing.

  10. Activated carbon fiber composite material and method of making

    SciTech Connect

    Burchell, Timothy D.; Weaver, Charles E.; Chilcoat, Bill R.; Derbyshire, Frank; Jagtoyen, Marit

    2000-01-01

    An activated carbon fiber composite for separation and purification, or catalytic processing of fluids is described. The activated composite comprises carbon fibers rigidly bonded to form an open, permeable, rigid monolith capable of being formed to near-net-shape. Separation and purification of gases are effected by means of a controlled pore structure that is developed in the carbon fibers contained in the composite. The open, permeable structure allows the free flow of gases through the monolith accompanied by high rates of adsorption. By modification of the pore structure and bulk density the composite can be rendered suitable for applications such as gas storage, catalysis, and liquid phase processing.

  11. Effect of combined activation on the preparation of high porous active carbons from granulated post-consumer polyethyleneterephthalate

    NASA Astrophysics Data System (ADS)

    Sych, N. V.; Kartel, N. T.; Tsyba, N. N.; Strelko, V. V.

    2006-09-01

    Activated carbons were prepared from granulated post-consumer PET by combined activation including heat treatment with sulphuric acid (chemical activation) followed by steam activation. The effect of activation time, temperature, impregnation coefficient in the activation process was studied in order to optimize those reception parameters. One of the most important parameter in combined activation of crushed PET was found to be impregnation coefficient. It was defined that the optimal impregnation coefficient is equal 28%. Activation temperature is another variability which has a significant effect on the pore volume evolution. The increasing of activation temperature enhances the surface area and pore volumes of active carbons. The yield of final product which composes of nearly 15% is the factor limited the activation temperature above 800 C. Textural characteristics of the samples were carried out by performing N 2 adsorption isotherm at -196 C. The obtained active carbons were mainly micro- and mesoporous and with BET apparent surface areas of up to 1030 m 2/g. The adsorption capacity on methylene blue reaches 1.0 mmol/g, the sorption activity on iodine comes to 77%.

  12. Bacterial production and carbon conversion based on saltmarsh plant debris

    NASA Astrophysics Data System (ADS)

    Newell, R. C.; Linley, E. A. S.; Lucas, M. I.

    1983-10-01

    There is a well-defined succession of micro-organisms which colonize powdered leaf debris from Spartina alterniflora and Juncus roemerianus, and aged natural detrital material when these were incubated in estuarine water at temperatures near to those recorded in the habitat at the time of collection. The natural assemblage of free-living bacteria in estuarine water rapidly enters logarithmic growth, subsequently declining with the increase in numbers of bactivorous microflagellates. These are then replaced by a mixed population of ciliates, choanoflagellates, amoeboid forms and attached bacteria which form part of a complex microbial community associated with particulate debris. The rate of increase of bacterial cells (?), in both spring and summer experiments ranged from 0010-0108 h -1 whilst estimates of bacterial carbon production ranged from 15 to 101 ?g C 1 -1 h -1, values which conform well with estimates obtained from natural assemblages of marine bacteria in coastal and estuarine waters elsewhere. Although both the ease of degradation of the detrital substrate and incubation temperature are of importance, enrichment of both powdered Spartina leaf debris and aged natural detritus with inorganic nutrients evidently enhances bacterial production under experimental conditions. In addition, the amount of carbon utilized to sustain bacterial carbon production shows a significant reduction following enrichment with NH 4, NO 3 or combinations of NO 3 + PO 4. The bacterial carbon conversion efficiency (?g C incorporated into bacterial production per ?g C consumed) 100, based on powdered Spartina leaves, and aged natural detritus, is thus increased from 9-14%, to as much as 38% in nutrient enriched media. Since NH 4, NO 3 and PO 4 values are generally low in the water column, it seems likely that bacteria achieve a carbon conversion of only 9-14% on natural suspended detrital material, with the possibility of an enhanced conversion of up to 38% occurring at the sediment-water interface where ammonia regeration occurs. This suggests that suspended bacteria which characterize estuarine waters of salt marsh areas may be responsible for the oxidation of 86-91% of the carbon which enters water column microheterotroph food chains, and are probably implicated in the large CO 2 fluxes recently recorded from coastal wetland habitats.

  13. India's cement industry: Productivity, energy efficiency and carbon emissions

    SciTech Connect

    Schumacher, Katja; Sathaye, Jayant

    1999-07-01

    Historical estimates of productivity growth in India's cement sector vary from indicating an improvement to a decline in the sector's productivity. The variance may be traced to the time period of study, source of data for analysis, and type of indices and econometric specifications used for reporting productivity growth. Analysis shows that in the twenty year period, 1973 to 1993, productivity in the aluminum sector increased by 0.8% per annum. An econometric analysis reveals that technical progress in India's cement sector has been biased towards the use of energy and capital, while it has been material and labor saving. The increase in productivity was mainly driven by a period of progress between 1983 and 1991 following partial decontrol of the cement sector in 1982. The authors examine the current changes in structure and energy efficiency in the sector. Their analysis shows that the Indian cement sector is moving towards world-best technology, which will result in fewer carbon emissions and more efficient energy use. However, substantial further energy savings and carbon reduction potentials still exist.

  14. Effect of silicate modulus and metakaolin incorporation on the carbonation of alkali silicate-activated slags

    SciTech Connect

    Bernal, Susan A.; Mejia de Gutierrez, Ruby; Provis, John L.; Rose, Volker

    2010-06-15

    Accelerated carbonation is induced in pastes and mortars produced from alkali silicate-activated granulated blast furnace slag (GBFS)-metakaolin (MK) blends, by exposure to CO{sub 2}-rich gas atmospheres. Uncarbonated specimens show compressive strengths of up to 63 MPa after 28 days of curing when GBFS is used as the sole binder, and this decreases by 40-50% upon complete carbonation. The final strength of carbonated samples is largely independent of the extent of metakaolin incorporation up to 20%. Increasing the metakaolin content of the binder leads to a reduction in mechanical strength, more rapid carbonation, and an increase in capillary sorptivity. A higher susceptibility to carbonation is identified when activation is carried out with a lower solution modulus (SiO{sub 2}/Na{sub 2}O ratio) in metakaolin-free samples, but this trend is reversed when metakaolin is added due to the formation of secondary aluminosilicate phases. High-energy synchrotron X-ray diffractometry of uncarbonated paste samples shows that the main reaction products in alkali-activated GBFS/MK blends are C-S-H gels, and aluminosilicates with a zeolitic (gismondine) structure. The main crystalline carbonation products are calcite in all samples and trona only in samples containing no metakaolin, with carbonation taking place in the C-S-H gels of all samples, and involving the free Na{sup +} present in the pore solution of the metakaolin-free samples. Samples containing metakaolin do not appear to have the same availability of Na{sup +} for carbonation, indicating that this is more effectively bound in the presence of a secondary aluminosilicate gel phase. It is clear that claims of exceptional carbonation resistance in alkali-activated binders are not universally true, but by developing a fuller mechanistic understanding of this process, it will certainly be possible to improve performance in this area.

  15. Carbon-Carbon Bond Cleavage in Activation of the Prodrug Nabumetone

    PubMed Central

    Varfaj, Fatbardha; Zulkifli, Siti N. A.; Park, Hyoung-Goo; Challinor, Victoria L.; De Voss, James J.

    2014-01-01

    Carbon-carbon bond cleavage reactions are catalyzed by, among others, lanosterol 14-demethylase (CYP51), cholesterol side-chain cleavage enzyme (CYP11), sterol 17β-lyase (CYP17), and aromatase (CYP19). Because of the high substrate specificities of these enzymes and the complex nature of their substrates, these reactions have been difficult to characterize. A CYP1A2-catalyzed carbon-carbon bond cleavage reaction is required for conversion of the prodrug nabumetone to its active form, 6-methoxy-2-naphthylacetic acid (6-MNA). Despite worldwide use of nabumetone as an anti-inflammatory agent, the mechanism of its carbon-carbon bond cleavage reaction remains obscure. With the help of authentic synthetic standards, we report here that the reaction involves 3-hydroxylation, carbon-carbon cleavage to the aldehyde, and oxidation of the aldehyde to the acid, all catalyzed by CYP1A2 or, less effectively, by other P450 enzymes. The data indicate that the carbon-carbon bond cleavage is mediated by the ferric peroxo anion rather than the ferryl species in the P450 catalytic cycle. CYP1A2 also catalyzes O-demethylation and alcohol to ketone transformations of nabumetone and its analogs. PMID:24584631

  16. Catalytic ozonation of p-chlorobenzoic acid by activated carbon and nickel supported activated carbon prepared from petroleum coke.

    PubMed

    Li, Xukai; Zhang, Qiuyun; Tang, Lili; Lu, Ping; Sun, Fengqiang; Li, Laisheng

    2009-04-15

    The aim of this research was to investigate catalytic activity of petroleum coke, activated carbon (AC) prepared from this material, Ni supported catalyst on activated carbon (Ni/AC) in the ozonation of aqueous phase p-chlorobenzoic acid (p-CBA). Activated carbon and Ni/AC catalyst were characterized by XRD and SEM. The presence of petroleum coke did not improve the degradation of p-CBA compared to ozonation alone, but it was advantageous for p-CBA mineralization (total organic carbon, TOC, reduction), indicating the generation of highly oxidant species (*OH) in the medium. The presence of either activated carbon or Ni/AC considerably improves TOC removal during p-CBA ozonation. Ni/AC catalyst shows the better catalytic activity and stability based on five repeated tests during p-CBA ozonation. During the ozonation (50 mg/h ozone flow rate) of a 10 mg/L p-CBA (pH 4.31), it can be more mineralized in the presence of Ni/AC catalyst (5.0 g/L), TOC removal rate is over 60% in 60 min, 43% using activated carbon as catalyst, only 30% with ozonation alone. PMID:18667273

  17. Ratio of Pion Kaon Production in Proton Carbon Interactions

    SciTech Connect

    Lebedev, Andrey V.; /Harvard U.

    2007-05-01

    The ratio of pion-kaon production by 120 GeV/c protons incident on carbon target is presented. The data was recorded with the Main Injector Particle Production experiment at Fermi National Accelerator Laboratory. Production ratios of K{sup +}/{pi}{sup +}, K{sup -}/{pi}{sup -}, K{sup -}/K{sup +}, and {pi}{sup -}/{pi}{sup +} are measured in 24 bins in longitudinal momentum from 20 to 90 GeV/c and transverse momentum up to 2 GeV/c. The measurement is compared to existing data sets, particle production Monte Carlo results from FLUKA-06, parametrization of proton-beryllium data at 400/450 GeV/c, and ratios measured by the MINOS experiment on the NuMI target.

  18. Apparatus for hydrogen and carbon production via carbon aerosol-catalyzed dissociation of hydrocarbons

    NASA Technical Reports Server (NTRS)

    Muradov, Nazim Z. (Inventor); Smith, Franklyn (Inventor); Tabatabaie-Raissi, Ali (Inventor)

    2012-01-01

    A novel process and apparatus is disclosed for sustainable, continuous production of hydrogen and carbon by catalytic dissociation or decomposition of hydrocarbons at elevated temperatures using in-situ generated carbon particles. Carbon particles are produced by decomposition of carbonaceous materials in response to an energy input. The energy input can be provided by at least one of a non-oxidative and oxidative means. The non-oxidative means of the energy input includes a high temperature source, or different types of plasma, such as, thermal, non-thermal, microwave, corona discharge, glow discharge, dielectric barrier discharge, or radiation sources, such as, electron beam, gamma, ultraviolet (UV). The oxidative means of the energy input includes oxygen, air, ozone, nitrous oxide (NO.sub.2) and other oxidizing agents. The method, apparatus and process of the present invention is applicable to any gaseous or liquid hydrocarbon fuel and it produces no or significantly less CO.sub.2 emissions compared to conventional processes.

  19. Wellbore stability analysis during the production of a carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Alves, J.-L.; Coehlo, L.; Baud, P.; Guevara Junior, N.

    2009-04-01

    Carbonate reservoirs represent a major part of the world oil and gas reserves. During production, the extraction of hydrocarbons reduces pore pressure and thus causes an increase in the effective stress and mechanical compaction in the reservoir. The compactive deformation and failure may be spatially extensive or localized to the vicinity of the wellbore, but in either case the consequences can be economically severe involving surface subsidence, well failure and various production problems. The analysis of wellbore stability and more generally of deformation and failure in carbonate environments hinges upon a relevant constitutive modeling of carbonate rocks over a wide range of porosities. In this study, we performed a wellbore stability analysis for a lateral wellbore junction in three dimensions. The complex geometry for the wellbore junction was modeled with tetrahedral finite elements considering a rate independent elastic-plastic isotropic material that presented linear behavior during elastic strain and associated flow rule. A finite element model simulating drilling and production phases were done for field conditions from a deep water reservoir in Campos basin, offshore Brazil. In this context, several scenarios were studied considering true 3D orientation for both in situ stresses and geometry of the wellbore junction itself. We discussed the impact of constitutive modeling on the wellbore stability, based on new experimental data on two micritic porous carbonates. Series of conventional triaxial experiments were performed at room temperature in dry and wet conditions on samples of Comiso and Tavel limestones of respective porosity 17 and 16%. The wet samples were deformed in drained conditions with 10 MPa pore pressure. The initial yield stresses were identified as the critical stresses at the onset of shear-enhanced compaction, subsequent yield stresses were considered to depend on hardening given by the plastic volumetric strain. For both limestones, we found that water had a moderate effect on the yield stresses but influenced significantly the hardening behavior of the rocks.

  20. Large-Area, Highly Ordered Array of Graphitic Carbon Materials Using Surface Active Chitosan Prepatterns.

    PubMed

    Baek, Youn-Kyoung; Kim, Dae Woo; Yang, Seung Bo; Lee, Jung-Goo; Kim, Young Kuk; Jung, Hee-Tae

    2015-02-01

    We demonstrate that chitosan prepatterns can generate not only highly periodic DNA pattern but also various types of graphitic carbon materials such as single-walled carbon nanotubes (SWNTs), graphene oxide (GO) and reduced graphene oxide (RGO). Scanning electron microscopy (SEM), fluorescence imaging and Raman spectroscopic results revealed that the graphitic carbon materials were selectively deposited on the surface of the periodic chitosan patterns by the electrostatic interaction between protonated amine groups of chitosan and the negative charged carbon materials. One proof-of-concept application of the system to the fabrication of electrical devices based on the micropatterns of SWNTs and RGO was also demonstrated. The strategy to use highly surface active chitosan pattern that can easily fabricate highly periodic pattern via a variety of lithographic tools may pave the way for the production of periodic arrays of graphitic carbon materials for large area device integration. PMID:26353637

  1. 40 CFR 415.300 - Applicability; description of the calcium carbonate production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... calcium carbonate production subcategory. 415.300 Section 415.300 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbonate Production Subcategory § 415.300 Applicability; description of the calcium carbonate production subcategory. The provisions of this subpart are applicable to...

  2. 40 CFR 415.300 - Applicability; description of the calcium carbonate production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... calcium carbonate production subcategory. 415.300 Section 415.300 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbonate Production Subcategory § 415.300 Applicability; description of the calcium carbonate production subcategory. The provisions of this subpart are applicable to...

  3. 40 CFR 415.300 - Applicability; description of the calcium carbonate production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... calcium carbonate production subcategory. 415.300 Section 415.300 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbonate Production Subcategory § 415.300 Applicability; description of the calcium carbonate production subcategory. The provisions of this subpart are applicable to...

  4. 40 CFR 415.300 - Applicability; description of the calcium carbonate production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... calcium carbonate production subcategory. 415.300 Section 415.300 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbonate Production Subcategory § 415.300 Applicability; description of the calcium carbonate production subcategory. The provisions of this subpart are applicable to...

  5. 40 CFR 415.300 - Applicability; description of the calcium carbonate production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... calcium carbonate production subcategory. 415.300 Section 415.300 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbonate Production Subcategory § 415.300 Applicability; description of the calcium carbonate production subcategory. The provisions of this subpart are applicable to...

  6. 40 CFR 415.450 - Applicability; description of the lithium carbonate production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... lithium carbonate production subcategory. 415.450 Section 415.450 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Lithium Carbonate Production Subcategory § 415.450 Applicability; description of the lithium carbonate production subcategory. The provisions of this subpart are applicable to...

  7. 40 CFR 415.450 - Applicability; description of the lithium carbonate production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... lithium carbonate production subcategory. 415.450 Section 415.450 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Lithium Carbonate Production Subcategory § 415.450 Applicability; description of the lithium carbonate production subcategory. The provisions of this subpart are applicable to...

  8. Decolorization/Deodorization of Zein via Activated Carbons and Molecular Sieves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of commercial activated carbons generated from different media and selective microporous zeolites with different pore sizes were used in a batch system to sequester the low molecular weight odor and color contaminants in commercial zein products. Because the adsorbents can also adsorb prot...

  9. Suomi NPP VIIRS active fire product status

    NASA Astrophysics Data System (ADS)

    Ellicott, E. A.; Csiszar, I. A.; Schroeder, W.; Giglio, L.; Wind, B.; Justice, C. O.

    2012-12-01

    We provide an overview of the evaluation and development of the Active Fires product derived from the Visible Infrared Imager Radiometer Suite (VIIRS) sensor on the Suomi National Polar-orbiting Partnership (SNPP) satellite during the first year of on-orbit data. Results from the initial evaluation of the standard SNPP Active Fires product, generated by the SNPP Interface Data Processing System (IDPS), supported the stabilization of the VIIRS Sensor Data Record (SDR) product. This activity focused in particular on the processing of the dual-gain 4 micron VIIRS M13 radiometric measurements into 750m aggregated data, which are fundamental for active fire detection. Following the VIIRS SDR product's Beta maturity status in April 2012, correlative analysis between VIIRS and near-simultaneous fire detections from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the NASA Earth Observing System Aqua satellite confirmed the expected relative detection rates driven primarily by sensor differences. The VIIRS Active Fires Product Development and Validation Team also developed a science code that is based on the latest MODIS Collection 6 algorithm and provides a full spatially explicit fire mask to replace the sparse array output of fire locations from a MODIS Collection 4 equivalent algorithm in the current IDPS product. The Algorithm Development Library (ADL) was used to support the planning for the transition of the science code into IDPS operations in the future. Product evaluation and user outreach was facilitated by a product website that provided end user access to fire data in user-friendly format over North America as well as examples of VIIRS-MODIS comparisons. The VIIRS fire team also developed an experimental product based on 375m VIIRS Imagery band measurements and provided high quality imagery of major fire events in US. By August 2012 the IDPS product achieved Beta maturity, with some known and documented shortfalls related to the processing of incorrect SDR input data and to apparent algorithm deficiencies in select observing and environmental conditions.

  10. Adsorption of dissolved natural organic matter by modified activated carbons.

    PubMed

    Cheng, Wei; Dastgheib, Seyed A; Karanfil, Tanju

    2005-06-01

    Adsorption of dissolved natural organic matter (DOM) by virgin and modified granular activated carbons (GACs) was studied. DOM samples were obtained from two water treatment plants before (i.e., raw water) and after coagulation/flocculation/sedimentation processes (i.e., treated water). A granular activated carbon (GAC) was modified by high temperature helium or ammonia treatment, or iron impregnation followed by high temperature ammonia treatment. Two activated carbon fibers (ACFs) were also used, with no modification, to examine the effect of carbon porosity on DOM adsorption. Size exclusion chromatography (SEC) and specific ultraviolet absorbance (SUVA(254)) were employed to characterize the DOMs before and after adsorption. Iron-impregnated (HDFe) and ammonia-treated (HDN) activated carbons showed significantly higher DOM uptakes than the virgin GAC. The enhanced DOM uptake by HDFe was due to the presence of iron species on the carbon surface. The higher uptake of HDN was attributed to the enlarged carbon pores and basic surface created during ammonia treatment. The SEC and SUVA(254) results showed no specific selectivity in the removal of different DOM components as a result of carbon modification. The removal of DOM from both raw and treated waters was negligible by ACF10, having 96% of its surface area in pores smaller than 1 nm. Small molecular weight (MW) DOM components were preferentially removed by ACF20H, having 33% of its surface area in 1--3 nm pores. DOM components with MWs larger than 1600, 2000, and 2700 Da of Charleston raw, Charleston-treated, and Spartanburg-treated waters, respectively, were excluded from the pores of ACF20H. In contrast to carbon fibers, DOM components from entire MW range were removed from waters by virgin and modified GACs. PMID:15927230

  11. Surface chemistry of carbon: activation of molecular oxygen

    NASA Astrophysics Data System (ADS)

    Atamny, F.; Blöcker, J.; Dübotzky, A.; Kurt, H.; Timpe, O.; Loose, G.; Mahdi, W.; Schlögl, R.

    Three different industrial carbon blacks were characterized in their surface chemistry with respect to their relative abilities to activate molecular oxygen. A variety of techniques was used including x-ray diffraction, gasification experiments, electron spectroscopy as XPS and UPS, helium ion scattering spectroscopy, thermal desorption spectroscopy and the catalytic oxidation of aqueous SO2 as a "chemical probe" for activated oxygen. The activation properties for molecular oxygen at high temperatures were probed by analysing the gasification characteristics in 5 vol % oxygen-inert gas mixtures; at low temperatures the activity in the oxidation of SO2 to sulfuric acid with molecular oxygen was taken as indicator. For this reaction the carbons had to be activated by ammonia treatment at elevated temperatures. Thermal desorption spectroscopy and valence band photoemission provided data for the identification of reaction intermediates in the activation process of oxygen. The important role of surface chemical anisotropy caused by vast differences in bulk crystal structure is pointed out. The results are discussed within a model of oxygen activation which assumes two types of surface sites differing in their π electron density. Sites, rich in π electrons are graphitic and can activate oxygen to the O2-2 species which is short-lived and can be accumulated in the carbon pores. Further activation involves dissociation of the peroxo group into O- species which finally react with the second sites with the formation of covalent carbon-oxygen bonds. The relative abundance of the low temperature reactive O2-2 species and the high temperature active O- species is on as-received carbons, low for the peroxo species, and can be enhanced considerably by modifying the abundance of graphitic surface patches on carbon black and by generating suitable porosity.

  12. Environmental Remediation and Conversion of Carbon Dioxide (CO2) into Useful Green Products by Accelerated Carbonation Technology

    PubMed Central

    Lim, Mihee; Han, Gi-Chun; Ahn, Ji-Whan; You, Kwang-Suk

    2010-01-01

    This paper reviews the application of carbonation technology to the environmental industry as a way of reducing carbon dioxide (CO2), a green house gas, including the presentation of related projects of our research group. An alternative technology to very slow natural carbonation is the co-called ‘accelerated carbonation’, which completes its fast reaction within few hours by using pure CO2. Carbonation technology is widely applied to solidify or stabilize solid combustion residues from municipal solid wastes, paper mill wastes, etc. and contaminated soils, and to manufacture precipitated calcium carbonate (PCC). Carbonated products can be utilized as aggregates in the concrete industry and as alkaline fillers in the paper (or recycled paper) making industry. The quantity of captured CO2 in carbonated products can be evaluated by measuring mass loss of heated samples by thermo-gravimetric (TG) analysis. The industrial carbonation technology could contribute to both reduction of CO2 emissions and environmental remediation. PMID:20195442

  13. Composite electrodes of activated carbon derived from cassava peel and carbon nanotubes for supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Taer, E.; Iwantono, Yulita, M.; Taslim, R.; Subagio, A.; Salomo, Deraman, M.

    2013-09-01

    In this paper, a composite electrode was prepared from a mixture of activated carbon derived from precarbonization of cassava peel (CP) and carbon nanotubes (CNTs). The activated carbon was produced by pyrolysis process using ZnCl2 as an activation agent. A N2 adsorption-desorption analysis for the sample indicated that the BET surface area of the activated carbon was 1336 m2 g-1. Difference percentage of CNTs of 0, 5, 10, 15 and 20% with 5% of PVDF binder were added into CP based activated carbon in order to fabricate the composite electrodes. The morphology and structure of the composite electrodes were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The SEM image observed that the distribution of CNTs was homogeneous between carbon particles and the XRD pattern shown the amorphous structure of the sample. The electrodes were fabricated for supercapacitor cells with 316L stainless steel as current collector and 1 M sulfuric acid as electrolyte. An electrochemical characterization was performed by using an electrochemical impedance spectroscopy (EIS) method using a Solatron 1286 instrument and the addition of CNTs revealed to improve the resistant and capacitive properties of supercapacitor cell.

  14. Alternating Authigenic and Carbonate Factory Production within a Cool-water Carbonate Sequence Stratigraphic Framework

    NASA Astrophysics Data System (ADS)

    Thompson, N. K.; Reid, C.; Bassett, K. N.

    2012-12-01

    Glaucony and phosphate production is characteristic of low sedimentation rates within low energy, oxygen-depleted environments, and is often associated with condensed sections and unconformities. Glaucony- and phosphate-rich rocks are often interpreted to be associated with sea-level highstands and maximum flooding surfaces, especially in siliciclastic systems. In contrast, our research shows that in the cool-water carbonate realm glaucony and, to an extent, phosphate are connected to lowstands and transgressions, requiring a reversal in the way they are interpreted within a sequence stratigraphic context. The Mid-Tertiary rocks of the Waitaki Basin, South Island, New Zealand, contain a cool-water carbonate and greensand succession formed on the eastern passive margin of the Zealandia continental fragment, and include two major sequence boundaries within a broad regional transgression. The palaeobasin contained an eastern outer shelf volcanic-induced high that acted like a platform rim, from where the basin deepened towards the west. The basal sequence contains a bryozoan grainstone facies that formed a shoal on the eastern volcanic seamount. This grades westward to a quartzose impure wackestone containing terrigenous material derived from low-lying islands of Zealandia far to the west. The overlying sequence boundary forms a karst surface associated with the high in the east, and a firmground in the west, and developed as a result of sea-level fall and lowstand conditions. During these lowstand conditions the terrigenous supply of silt and clay material was moved closer to the Waitaki Basin and this was then available for glauconitisation. Calcareous glaucony- and phosphate-rich greensands accumulated during the subsequent transgression, with the glaucony and phosphate content decreasing through this second sequence to form pure packstones during highstand and early regression. The second sequence boundary overlying these packstones shows similar karst and firmground distribution to the first, and has a similar greensand transgressive sequence deposited above it. In this cool-water setting, where the carbonate factory is located on an offshore volcanic-induced high, authigenic mineral production occurs at lowstand settings. During lowstand, mud-sized terrigenous clay minerals are introduced to the basin from the west, smothering the carbonate factory and supplying the building blocks for glaucony production. Through the transgressive phase this terrigenous clay supply is progressively shut down and the system returns to carbonate production at highstand. Sea-level rise in such an environment encourages the development of the cool-water carbonate factory, and thus a decrease in production from the 'authigenic factory'.

  15. Towards efficient solar hydrogen production by intercalated carbon nitride photocatalyst.

    PubMed

    Gao, Honglin; Yan, Shicheng; Wang, Jiajia; Huang, Yu An; Wang, Peng; Li, Zhaosheng; Zou, Zhigang

    2013-11-01

    The development of efficient photocatalytic material for converting solar energy to hydrogen energy as viable alternatives to fossil-fuel technologies is expected to revolutionize energy shortage and environment issues. However, to date, the low quantum yield for solar hydrogen production over photocatalysts has hindered advances in the practical applications of photocatalysis. Here, we show that a carbon nitride intercalation compound (CNIC) synthesized by a simple molten salt route is an efficient polymer photocatalyst with a high quantum yield. We found that coordinating the alkali metals into the C-N plane of carbon nitride will induce the un-uniform spatial charge distribution. The electrons are confined in the intercalated region while the holes are in the far intercalated region, which promoted efficient separation of photogenerated carriers. The donor-type alkali metal ions coordinating into the nitrogen pots of carbon nitrides increase the free carrier concentration and lead to the formation of novel nonradiative paths. This should favor improved transport of the photogenerated electron and hole and decrease the electron-hole recombination rate. As a result, the CNIC exhibits a quantum yield as high as 21.2% under 420 nm light irradiation for solar hydrogen production. Such high quantum yield opens up new opportunities for using cheap semiconducting polymers as energy transducers. PMID:24061109

  16. Forests and ozone: productivity, carbon storage, and feedbacks

    PubMed Central

    Wang, Bin; Shugart, Herman H.; Shuman, Jacquelyn K.; Lerdau, Manuel T.

    2016-01-01

    Tropospheric ozone is a serious air-pollutant, with large impacts on plant function. This study demonstrates that tropospheric ozone, although it damages plant metabolism, does not necessarily reduce ecosystem processes such as productivity or carbon sequestration because of diversity change and compensatory processes at the community scale ameliorate negative impacts at the individual level. This study assesses the impact of ozone on forest composition and ecosystem dynamics with an individual-based gap model that includes basic physiology as well as species-specific metabolic properties. Elevated tropospheric ozone leads to no reduction of forest productivity and carbon stock and to increased isoprene emissions, which result from enhanced dominance by isoprene-emitting species (which tolerate ozone stress better than non-emitters). This study suggests that tropospheric ozone may not diminish forest carbon sequestration capacity. This study also suggests that, because of the often positive relationship between isoprene emission and ozone formation, there is a positive feedback loop between forest communities and ozone, which further aggravates ozone pollution. PMID:26899381

  17. Forests and ozone: productivity, carbon storage, and feedbacks.

    PubMed

    Wang, Bin; Shugart, Herman H; Shuman, Jacquelyn K; Lerdau, Manuel T

    2016-01-01

    Tropospheric ozone is a serious air-pollutant, with large impacts on plant function. This study demonstrates that tropospheric ozone, although it damages plant metabolism, does not necessarily reduce ecosystem processes such as productivity or carbon sequestration because of diversity change and compensatory processes at the community scale ameliorate negative impacts at the individual level. This study assesses the impact of ozone on forest composition and ecosystem dynamics with an individual-based gap model that includes basic physiology as well as species-specific metabolic properties. Elevated tropospheric ozone leads to no reduction of forest productivity and carbon stock and to increased isoprene emissions, which result from enhanced dominance by isoprene-emitting species (which tolerate ozone stress better than non-emitters). This study suggests that tropospheric ozone may not diminish forest carbon sequestration capacity. This study also suggests that, because of the often positive relationship between isoprene emission and ozone formation, there is a positive feedback loop between forest communities and ozone, which further aggravates ozone pollution. PMID:26899381

  18. A sustainable route for the preparation of activated carbon and silica from rice husk ash.

    PubMed

    Liu, Yan; Guo, Yupeng; Zhu, Yanchao; An, Dongmin; Gao, Wei; Wang, Zhuo; Ma, Yuejia; Wang, Zichen

    2011-02-28

    An environmentally friendly and economically effective process to produce silica and activated carbon form rice husk ask simultaneously has been developed in this study. An extraction yield of silica of 72-98% was obtained and the particle size was 40-50 nm. The microstructures of the as-obtained silica powders were characterized by X-ray diffraction (XRD) and infrared spectra (IR). The surface area, iodine number and capacitance value of activated carbon could achieve 570 m(2)/g, 1708 mg/g, 180 F/g, respectively. In the whole synthetic procedure, the wastewater and the carbon dioxide were collected and reutilized. The recovery rate of sodium carbonate was achieved 92.25%. The process is inexpensive, sustainable, environmentally friendly and suitable for large-scale production. PMID:21194835

  19. REMOVAL OF ORGANIC POLLUTANTS FROM SUBCRITICAL WATER WITH ACTIVATED CARBON

    SciTech Connect

    Steven B. Hawthorne; Arnaud J. Lagadec

    1999-08-01

    The Energy & Environmental Research Center (EERC) has demonstrated that controlling the temperature (and to a lesser extent, the pressure) of water can dramatically change its ability to extract organics and inorganics from matrices ranging from soils and sediments to waste sludges and coal. The dielectric constant of water can be changed from about 80 (a very polar solvent) to <5 (similar to a nonpolar organic solvent) by controlling the temperature (from ambient to about 400 C) and pressure (from about 5 to 350 bar). The EERC has shown that hazardous organic pollutants such as pesticides, PACS (polycyclic aromatic hydrocarbons), and PCBs (polychlorinated biphenyls) can be completely removed from soils, sludges, and sediments at temperatures (250 C) and pressures (<50 atm) that are much milder than typically used for supercritical water processes (temperature >374 C, pressure >221 atm). In addition, the process has been demonstrated to be particularly effective for samples containing very high levels of contaminants (e.g., part per thousand). Current projects include demonstrating the subcritical water remediation process at the pilot scale using an 8-liter system constructed under separate funding during 1997. To date, subcritical water has been shown to be an effective extraction fluid for removing a variety of organic pollutants from soils and sludges contaminated with fossil fuel products and waste products, including PACS from soil (e.g., town gas sites), refining catalysts, and petroleum tank bottom sludges; PCBs from soil and sediments; toxic gasoline components (e.g., benzene) from soil and waste sludge; and phenols from petroleum refinery sludges. The obvious need to clean the wastewater from subcritical water processes led to preliminary experiments with activated carbon placed in line after the extractor. Initial experiments were performed before and after cooling the extractant water (e.g., with water at 200 C and with water cooled to 25 C). Surprisingly, the ability of activated carbon to remove organics from the water is better at a high temperature than at room temperature. These initial results are opposite to those expected from chromatographic theory, since the solubility of the organics is about 100,000-fold higher in the hot water than in ambient water. At present, the physicochemical mechanism accounting for these results is unknown; however, it is possible that the lower surface tension and lower viscosity of subcritical water (compared to water at ambient conditions) greatly increases the available area of the carbon by several orders of magnitude. Regardless of the mechanism involved, the optimal use of activated carbon to clean the wastewater generated from subcritical water remediation will depend on obtaining a better understanding of the controlling parameters. While these investigations focused on the cleanup of wastewater generated from subcritical water remediation, the results also apply to cleanup of any wastewater contaminated with nonpolar and moderately polar organics such as wastewaters from coal and petroleum processing.

  20. Removal of congo red using activated carbon and its regeneration.

    PubMed

    Purkait, M K; Maiti, A; DasGupta, S; De, S

    2007-06-25

    Activated carbon is used for the removal of colored toxic congo red dye. The effects of different operating conditions like, initial dye concentration, contact time, pH and temperature are studied for adsorption of congo red by a known amount of activated carbon (1.0g/L) under stirred batch condition. The zero point of charge of the activated carbon is found about 6.6. About 90% dye is removed for initial concentration of 50 and 100mg/L, it is about 80% at pH 7.0. Maximum adsorption (about 100%) of dye is observed at pH 2.0 for the concentration range studied here. Freundlich isotherm is found to fit the equilibrium data more adequately. Pseudo second order kinetic model explain successfully the kinetic data. The surfactant enhanced carbon regeneration (SECR) technique using both cationic and anionic surfactants is adopted for the regeneration of spent carbon by desorbing the dye. A kinetic model for dye desorption from the commercial activated carbon (CAC) is also proposed. Anionic surfactants show better performance than the cationic ones. Efficiency of dye desorption using surfactants is also compared with the desorption using pH change. PMID:17178190

  1. Activated Carbon Composites for Air Separation

    SciTech Connect

    Contescu, Cristian I; Baker, Frederick S; Tsouris, Costas; McFarlane, Joanna

    2008-03-01

    In continuation of the development of composite materials for air separation based on molecular sieving properties and magnetic fields effects, several molecular sieve materials were tested in a flow system, and the effects of temperature, flow conditions, and magnetic fields were investigated. New carbon materials adsorbents, with and without pre-loaded super-paramagnetic nanoparticles of Fe3O4 were synthesized; all materials were packed in chromatographic type columns which were placed between the poles of a high intensity, water-cooled, magnet (1.5 Tesla). In order to verify the existence of magnetodesorption effect, separation tests were conducted by injecting controlled volumes of air in a flow of inert gas, while the magnetic field was switched on and off. Gas composition downstream the column was analyzed by gas chromatography and by mass spectrometry. Under the conditions employed, the tests confirmed that N2 - O2 separation occurred at various degrees, depending on material's intrinsic properties, temperature and flow rate. The effect of magnetic fields, reported previously for static conditions, was not confirmed in the flow system. The best separation was obtained for zeolite 13X at sub-ambient temperatures. Future directions for the project include evaluation of a combined system, comprising carbon and zeolite molecular sieves, and testing the effect of stronger magnetic fields produced by cryogenic magnets.

  2. Production and transport of convoy electrons in amorphous carbon foils

    SciTech Connect

    Gibbons, J.P.; Elston, S.B.; DeSerio, R.; Biedermann, C.; Breinig, M.; Gonzalez-Lepera, C.E.; Heil, O.; Huelskoetter, H.P.; Rothard, H.; Sellin, I.A.; Vane, C.R.

    1988-01-01

    The production of free convoy electrons, emitted with velocities near the ion velocity in ion-solid collisions, is not well understood. Experiments concerning thickness-dependent yields have suggested the dominant mechanism for convoy production is electron loss to the continuum (ELC) in the bulk of the solid. Free electrons created in the bulk are subject to multiple elastic and inelastic scattering during transport through remaining layers of the solid. We discuss doubly-differential measurements of convoy measurements of convoy electrons as a function of target thickness for fast O/sup 5 +/ ion projectiles incident on carbon foils of varied thicknesses. Angular distributions confirm the ELC model for convoy production. From the radial broadening of the convoy cusps we have determined energy and angular spreading parameters due to post-collisional multiple scattering. 8 refs., 2 figs., 1 tab.

  3. Porous texture evolution in Nomex-derived activated carbon fibers.

    PubMed

    Villar-Rodil, S; Denoyel, R; Rouquerol, J; Martínez-Alonso, A; Tascón, J M D

    2002-08-01

    In the present work, the textural evolution of a series of activated carbon fibers with increasing burn-off degree, prepared by the pyrolysis and steam activation of Nomex aramid fibers, is followed by measurements of physical adsorption of N(2) (77 K) and CO(2) (273 K) and immersion calorimetry into different liquids (dichloromethane, benzene, cyclohexane). The immersion calorimetry results are discussed in depth, paying special attention to the choice of the reference material. The activated carbon fibers studied possess an essentially homogeneous microporous texture, which suggests that these materials may be applied in gas separation, either directly or with additional CVD treatment. PMID:16290775

  4. Effects of activated carbon on the reactions of free chlorine with phenols

    SciTech Connect

    Voudrias, E.A.; Larson, R.A.; Snoeyink, V.L.

    1985-01-01

    The use of prechlorination in drinking water treatment results in contact of free chlorine with activated carbon which has been added to remove organic compounds from water. The chlorine then reacts with the carbon and adsorbed compounds. Free chlorine reacts readily with a group of phenolic compounds (phenol, guaiacol, catechol, 2,6-dimethoxyphenol, and p-chlorophenol) in dilute aqueous solutions (10/sup -5/ M) to produce mono-, di-, or trichloro derivatives, but when it reacts with phenols adsorbed on granular activated carbon (GAC), many additional products are formed. GAC exposed to chlorine becomes capable of promoting reactions such as hydroxylations of the aromatic ring, oxidation to quinones, chlorine substitution, carboxylation, and oxidative coupling (dimer formation). The formation of chlorohydroxybiphenyls (hydroxylated PCBs) (in vivo metabolites of PCBs) is particularly important because of their potential toxicity. Such compounds are the main reaction products from chlorophenols, but they are also formed in smaller amounts from nonchlorinated phenols (phenol and guaiacol).

  5. Measured Enthalpies of Adsorption of Boron-Doped Activated Carbons

    NASA Astrophysics Data System (ADS)

    Beckner, M.; Romanos, J.; Dohnke, E.; Singh, A.; Schaeperkoetter, J.; Stalla, D.; Burress, J.; Jalisatgi, S.; Suppes, G.; Hawthorne, M. F.; Yu, P.; Wexler, C.; Pfeifer, P.

    2012-02-01

    There is significant interest in the properties of boron-doped activated carbons for their potential to improve hydrogen storage.ootnotetextMultiply Surface-Functionalized Nanoporous Carbon for Vehicular Hydrogen Storage, P. Pfeifer et al. DOE Hydrogen Program 2011 Annual Progress Report, IV.C.3, 444-449 (2011). Boron-doped activated carbons have been produced using a process involving the pyrolysis of decaborane (B10H14) and subsequent high-temperature annealing. In this talk, we will present a systematic study of the effect of different boron doping processes on the samples' structure, hydrogen sorption, and surface chemistry. Initial room temperature experiments show a 20% increase in the hydrogen excess adsorption per surface area compared to the undoped material. Experimental enthalpies of adsorption will be presented for comparison to theoretical predictions for boron-doped carbon materials. Additionally, results from a modified version of the doping process will be presented.

  6. Study of the anodic arc discharge for carbon nanotube production

    NASA Astrophysics Data System (ADS)

    Waldorff, Erik; Keidar, Michael; Wass, Anthony; Friedmann, Peretz

    2003-10-01

    Carbon nanotubes (CNTs) are unique nanostructures with remarkable electronic and mechanical properties. CNTs are currently considered to be a promising candidate as a next generation material having various applications. To-date, a variety of CNT fabrication methods have been developed, among them is an arc discharge method. Arc discharge is a relatively simple method having high rate of CNT production. In this method single-wall and multi-wall nanotubes are produced from an ionized carbon plasma with joule heating from the discharge used to generate the plasma. The University of Michigan carbon nanotube production facility in the Aerospace Engineering Department utilizes the anodic arc discharge. In this type of discharge, the Carbon plasma is supplied mainly by the anode ablation. In addition a buffer gas (Helium) with a pressure range of 100-1000 torr is introduced into the discharge chamber. The experimental anode ablation rate is about 2-4 m3/s and generally increases with the background gas pressure in the considered pressure range.A model of the anodic arc discharge is developed. The main component of this model is the anode ablation kinetics that takes into account the non-free nature of ablation due to the presence of a high-density discharge plasma. Different characteristic sub-regions near the surface, namely, space-charge sheath, Knudsen layer, presheath and a hydrodynamic layer are considered. The ablation rate is determined by the flow velocity at the edge of the Knudsen layer. Coupling solution of the non-equilibrium, Knudsen layer, with hydrodynamic layer and discharge column provides self-consistent solution for the ablation rate and plasma parameter distribution.

  7. Distribution of and changes in industrial carbon dioxide production

    NASA Astrophysics Data System (ADS)

    Rotty, Ralph M.

    1983-02-01

    The burning of fossil fuels is believed to be the major source responsible for an observed increase in the concentration of carbon dioxide in the atmosphere now measured at many locations around the world. This paper revises earlier published data on the annual amounts of carbon released to the atmosphere during the period 1950-1978 and updates the record through 1980. A latitudinal distribution of the fossil fuel source is presented as an aid in explaining the differences in the observed CO2 concentrations at several stations. Data from Mauna Loa Observatory, the South Pole, and elsewhere around the world [Keeling et al., 1978a, b; Bolin and Bischof, 1970; Herbert, 1980] show an increase in the concentration of carbon dioxide in the atmosphere. Attempts to deduce from these records information about the global carbon cycle depend upon data pertaining to the sources of CO2 introduced by man-burning of fossil fuels and conversion of the world's forests. The latitudinal distribution of the fossil fuel production of CO2 should be an important aid in carbon-cycle analysis. Observations in the atmosphere show that the Northern Hemisphere CO2 concentration is increasing more rapidly than the Southern Hemisphere concentration and that the most rapid increase is at 50°-60°N latitude. The greatest seasonal variation also occurs in this latitude band. This paper updates and documents the fossil fuel sources of CO2. It revises global CO2 emission values for 1950-1978 published earlier; it demonstrates that a change in the rate of increase of annual CO2 emissions occurred in 1973; and it attempts to delineate the regional distribution of this source of CO2.

  8. Distribution of and changes in industrial carbon dioxide production

    SciTech Connect

    Rotty, R.M.

    1983-02-20

    The burning of fossils fuels is believed to be the major source responsible for an observed increase in the concentration of carbon dioxide in the atmosphere now measured at many locations around the world. This paper revises earlier published data on the annual amounts of carbon released to the atmosphere during the period 1950--1978 and updates the record through 1980. A latitudinal distribution of the fossil fuel source is presented as an aid in explaining the differences in the observed CO/sub 2/ concentrations at several stations. Data from Mauna Loa Observatory, the South Pole, and elsewhere around the world (Keeling et al., 1978a, b; Bolin and Bischof, 1970; Herbert, 1980) show an increase in the concentration of carbon dioxide in the atmosphere. Attempts to deduce from these records information about the global carbon cycle depend upon data pertaining to the sources of CO/sub 2/ introduced by man: burning of fossil fuels and conversion of the world's forests. The latitudinal distribution of the fossil fuel production of CO/sub 2/ should be an important aid in carbon-cycle analysis. Observations in the atmosphere show that the Northern Hemisphere CO/sub 2/ concentration is increasing more rapidly than the Southern Hemisphere concentration and that the most rapid increase is at 50/sup 0/--60/sup 0/N latitude. The greatest seasonal variation also occurs in this latitude band. This paper updates and documents the fossil fuel sources of CO/sub 2/. It revises global CO/sub 2/ emission values for 1950--1978 published earlier; it demonstrates that a change in the rate of increase of annual CO/sub 2/ emissions occurred in 1973; and it attempts to delineate the regional distribution of this source of CO/sub 2/.

  9. FENTON-DRIVEN REGENERATION OF GRANULAR ACTIVATED CARBON: A TECHNOLOGY OVERVIEW

    EPA Science Inventory

    A Fenton-driven mechanism for regenerating spent granular activated carbon (GAC) involves the combined, synergistic use of two reliable and well established treatment technologies - adsorption onto activated carbon and Fenton oxidation. During carbon adsorption treatment, enviro...

  10. 40 CFR 60.1820 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or... dioxins/furans and mercury stack test, determine the average carbon feed rate in kilograms (or pounds)...

  11. Treatment of activated carbon to enhance catalytic activity for reduction of nitric oxide with ammonia

    SciTech Connect

    Ku, B.J.; Rhee, H.K. . Dept. of Chemical Engineering); Lee, J.K.; Park, D. )

    1994-11-01

    Catalytic activity of activated carbon treated with various techniques was examined in a fixed bed reactor for the reduction of nitric oxide with ammonia at 150 C. Activated carbon derived from coconut shell impregnated with an aqueous solution of ammonium sulfate, further treated with sulfuric acid, dried at 120 C, and then heated in an inert gas stream at 400 C, showed the highest catalytic activity within the range of experimental conditions. The enhancement of catalytic activity of modified activated carbon could be attributed to the increase in the amount of oxygen function groups which increased the adsorption site for ammonia. Catalytic activity of activated carbons depended on the surface area and the oxygen content as well.

  12. TOXIC SUBSTANCE REMOVAL IN ACTIVATED SLUDGE AND PAC (POWDERED ACTIVATED CARBON) TREATMENT SYSTEMS

    EPA Science Inventory

    The effectiveness of adding powdered activated carbon to activated sludge systems was evaluated for enhanced removal of specific toxic organic compounds. Nine organic compounds encompassing a range of solubility, volatility, biodegradability, and adsorptive properties were studie...

  13. Free nitrous acid pretreatment of wasted activated sludge to exploit internal carbon source for enhanced denitrification.

    PubMed

    Ma, Bin; Peng, Yongzhen; Wei, Yan; Li, Baikun; Bao, Peng; Wang, Yayi

    2015-03-01

    Using internal carbon source contained in waste activated sludge (WAS) is beneficial for nitrogen removal from wastewater with low carbon/nitrogen ratio, but it is usually limited by sludge disintegration. This study presented a novel strategy based on free nitrous acid (FNA) pretreatment to intensify the release of organic matters from WAS for enhanced denitrification. During FNA pretreatment, soluble chemical oxygen demand (SCOD) production kept increasing when FNA increased from 0 to 2.04 mg HNO2-N/L. Compared with untreated WAS, the internal carbon source production increased by 50% in a simultaneous fermentation and denitrification reactor fed with WAS pretreated by FNA for 24 h at 2.04 mg HNO2-N/L. This also increased denitrification efficiency by 76% and sludge reduction by 87.5%. More importantly, greenhouse gas nitrous oxide production in denitrification was alleviated since more electrons could be provided by FNA pretreated WAS. PMID:25514398

  14. Simulating the effects of light intensity and carbonate system composition on particulate organic and inorganic carbon production in Emiliania huxleyi.

    PubMed

    Holtz, Lena-Maria; Wolf-Gladrow, Dieter; Thoms, Silke

    2015-05-01

    Coccolithophores play an important role in the marine carbon cycle. Variations in light intensity and external carbonate system composition alter intracellular carbon fluxes and therewith the production rates of particulate organic and inorganic carbon. Aiming to find a mechanistic explanation for the interrelation between dissolved inorganic carbon fluxes and particulate carbon production rates, we develop a numerical cell model for Emiliania huxleyi, one of the most abundant coccolithophore species. The model consists of four cellular compartments, for each of which the carbonate system is resolved dynamically. The compartments are connected to each other and to the external medium via substrate fluxes across the compartment-confining membranes. By means of the model we are able to explain several pattern observed in particulate organic and inorganic carbon production rates for different strains and under different acclimation conditions. Particulate organic and inorganic carbon production rates for instance decrease at very low external CO2 concentrations. Our model suggests that this effect is caused mainly by reduced HCO3(-) uptake rates, not by CO2 limitation. The often observed decrease in particulate inorganic carbon production rates under Ocean Acidification is explained by a downregulation of cellular HCO3(-) uptake. PMID:25747776

  15. Adsorption isotherms for chlorinated phenols on activated carbons

    SciTech Connect

    Colella, L.S.; Armenante, P.M.; Kafkewitz, D.; Allen, S.J.; Balkasundaram, V.

    1998-07-01

    The adsorption of 12 mono-, di-, and trichlorophenols from aqueous solutions on different activated carbons was studied. Distilled water and a minimal salt medium solution previously used in biotreatment studies with anaerobic organisms were used as solvents. A commercially available wood-based activated carbon (Chemviron carbon) and a lignite-based carbon produced at Queen`s University were used as the adsorbents. The Chemviron carbon was used in both granular and powder forms. The adsorption data for each chlorophenol were regressed using the Freundlich equation. The fit was generally satisfactory, especially since the range of chlorophenol concentrations tested in this work extended over 6 orders of magnitude. The exponents of the chlorophenol concentration term in the Freundlich equations were found to be in the relatively narrow range 0.127--0207. Therefore an attempt was made to regress all the data for all chlorophenols using a single isotherm, and a cumulative Freundlich isotherm was obtained. The Chemviron carbon was found to have a higher adsorbing capacity than the lignite-based carbon. The presence of additional inorganic solutes in the aqueous phase was found to have a negligible influence on adsorption.

  16. A comparison of the electrochemical behavior of carbon aerogels and activated carbon fiber cloths

    SciTech Connect

    Tran, T.D.; Alviso, C.T.; Hulsey, S.S.; Nielsen, J.K.; Pekala, R.W.

    1996-05-10

    Electrochemical capacitative behavior of carbon aerogels and commercial carbon fiber cloths was studied in 5M KOH, 3M sulfuric acid, and 0.5M tetrethylammonium tetrafluoroborate/propylene carbonate electrolytes. The resorcinol-formaldehyde based carbon aerogels with a range of denisty (0.2-0.85 g/cc) have open-cell structures with ultrafine pore sizes (5-50 nm), high surface area (400-700 m{sup 2}/g), and a solid matrix composed of interconnected particles or fibers with characteristic diameters of 10 nm. The commercial fiber cloths in the density range 0.2-04g/cc have high surface areas (1000-2500 m{sup 2}/g). The volumetric capacitances of high-density aerogels are shown to be comparable to or exceeding those from activated carbon fibers. Electrochemical behavior of these materials in various electrolytes is compared and related to their physical properties.

  17. Transition metal activation and functionalization of carbon-hydrogen bonds

    SciTech Connect

    Jones, W.D.

    1991-06-01

    This project is directed towards the continued investigation of the fundamental thermodynamic and kinetic factors that influence carbon-hydrogen bond activation at homogeneous transition metal centers. The project is also directed towards the conversion of hydrocarbons into functionalized products of potential use to the chemical industry. In the past two years, advances have been made in both understanding the interactions of hydrocarbons with metals and in the functionalization of hydrocarbons. Major advances that have been made include: (1) We have found that RhCl(PR{sub 3}){sub 2}(CNR) complexes can catalyze the insertion of isonitriles into the C-H bonds of arenes upon photolysis. (2) We have also examined reactions of a series of arenes with (C{sub 5}Me{sub 5})Rh(PMe{sub 3})PhH and begun to map out the kinetic and thermodynamic preferences for arene coordination. (3) We have begun to examine the reactions of rhodium isonitrile pyrazolylborates for alkane and arene C-H bond activation. A new, labile, carbodiimide precursor has been developed for these studies. (4) We have completed studies of the reactions of (C{sub 5}Me{sub 5)}Rh(PMe{sub 3})H{sub 2} with D{sub 2} and PMe{sub 3} that indicate that both {eta}{sup 5} {yields} {eta}{sup 3} ring slippage and metal to ring hydride migration occur more facilely than thermal reductive elimination of H{sub 2}. (5) We have examined the reactions of heterocycles with (C{sub 5}Me{sub 5})Rh(PMe{sub 3})PhH and found that pyrrole and furan undergo C-H or N-H activation. Thiophene, however, undergoes C-S bond oxidative addition, and the mechanism of activation has been shown to proceed through sulfur coordination prior to C-S insertion. 43 refs., 9 figs., 4 tabs.

  18. One-carbon substrate-based biohydrogen production: microbes, mechanism, and productivity.

    PubMed

    Rittmann, Simon K-M R; Lee, Hyun Sook; Lim, Jae Kyu; Kim, Tae Wan; Lee, Jung-Hyun; Kang, Sung Gyun

    2015-01-01

    Among four basic mechanisms for biological hydrogen (H2) production, dark fermentation has been considered to show the highest hydrogen evolution rate (HER). H2 production from one-carbon (C1) compounds such as formate and carbon monoxide (CO) is promising because formate is an efficient H2 carrier, and the utilization of CO-containing syngas or industrial waste gas may render the industrial biohydrogen production process cost-effective. A variety of microbes with the formate hydrogen lyase (FHL) system have been identified from phylogenetically diverse groups of archaea and bacteria, and numerous efforts have been undertaken to improve the HER for formate through strain optimization and bioprocess development. CO-dependent H2 production has been investigated to enhance the H2 productivity of various carboxydotrophs via an increase in CO gas-liquid mass transfer rates and the construction of genetically modified strains. Hydrogenogenic CO-conversion has been applied to syngas and by-product gas of the steel-mill process, and this low-cost feedstock has shown to be promising in the production of biomass and H2. Here, we focus on recent advances in the isolation of novel phylogenetic groups utilizing formate or CO, the remarkable genetic engineering that enhances H2 productivity, and the practical implementation of H2 production from C1 substrates. PMID:25461503

  19. Production of carbonate sediments by a unicellular green alga

    USGS Publications Warehouse

    Yates, K.K.; Robbins, L.L.

    1998-01-01

    This study investigates the ability of the unicellular green alga Natmochloris atoimis to precipitate CaCO3, quantifies mineral precipitation rates, estimates sediment production in a N. atomiis bloom, and discusses the implications of microbial calcification for carbonate sediment deposition. A series of N. atomus cultures, isolated from Lake Reeve, Australia, were incubated at various pH and calcium concentrations to determine environmental parameters for calcification. Rates of calcification were calculated from initial and postincubation alkalinity, pH, and calcium measurements. Replicate experiments and controls consisting of non-calcifying cultures, uninoculated media, and dead cell cultures were performed using environmental culture parameters determined in series cultures. Average calcification rates from replicate experiments were used to predict daily sediment production rates in a small bloom of N. atomus. N. atomus precipitates 0.138 g/L of calcite in approximately 4 h when incubated at pH 8.5, 14.24 mM calcium concentration, 33 ??C, 100 ??E/m2/s light intensity, and a cell population density of 107 cells/mL. Assuming continuous precipitation, this corresponds to a maximum estimated sediment production rate of 1.6 ?? 106 kg of CaCO3, per 12 h day in a single bloom of 3.2 ?? 109 L. Our results suggest that microbial calcification contributes significantly to the carbonate sediment budget.

  20. Sorption of atrazine on conventional and surface modified activated carbons.

    PubMed

    Chingombe, P; Saha, B; Wakeman, R J

    2006-10-15

    The sorption of atrazine from water has been studied using a conventional activated carbon, F400, an annealed carbon sample, F400AN, and an aminated carbon sample, F400NH(2). Characterisation of the carbon samples showed that sample F400NH(2) had the highest proportion of micropores, but had the lowest values of point of zero charge (PZC) and iso-electric point (IEP). This was attributed to the existence of a high proportion of oxygen containing functional groups. Sorption data showed that sample F400AN was superior in the sorption of atrazine to samples F400 and F400NH(2). It was noted that pore size distribution alone was not the only contributing factor for the uptake of atrazine onto the activated carbons. The sorption data were fitted well using the Freundlich isotherm. The free energy change showed that sorption of atrazine on activated carbons is a spontaneous process. A pseudo-second order kinetic model was used for analysing the kinetic data, and it was concluded that adsorption of atrazine was controlled by a film diffusion mechanism. PMID:16870200

  1. Influence of the precursor metamorphism degree on preparation of nitrogen-enriched activated carbons by ammoxidation and chemical activation of coals

    SciTech Connect

    Piotr Nowicki; Robert Pietrzak; Helena Wachowska

    2009-04-15

    The paper presents results of a study on obtaining N-enriched active carbons from four hard coals with different degree of metamorphism. The starting materials were carbonized, activated with KOH, and ammoxidized by a mixture of ammonia and air at the ratio 1:3 at 300 and 350{sup o}C, at each stage of the active carbon production. The efficiency of ammoxidation was found to depend on the degree of metamorphism of the precursor, the stage of processing at which ammoxidation is performed, and the temperature of this process. Ammoxidation of the active carbon led to a decrease in their surface area and pore volume, whereas that performed both at the stage of the precursor and the carbonizate brought improvement of textural parameters of the active carbons obtained. The sequence of the carbonization, activation, and ammoxidation processes had a significant effect on the acid-base character of the active carbon samples obtained. The majority of the active carbons modified at the stage of precursor and carbonizate showed considerable prevalence of surface acidic groups, whereas the samples ammoxidized after activation showed an intermediate acidic-basic character of the surface. 25 refs., 4 figs., 9 tabs.

  2. Pseudomonas aeruginosa biosurfactant production in continuous culture with glucose as carbon source

    SciTech Connect

    Guerra-Santos, L.; Kaeppeli, O.; Fiechter, A.

    1984-08-01

    Interest in microbial surfactants has increased considerably in recent years, especially due to their potential application in enhanced oil recovery. Rsan-ver, a strain of Pseudomonas aeruginosa, was used for the development of a continuous process for biosurfactant production. The active compounds were identified as rhamnolipids. A final medium for production was designed in continuous culture by means of medium shifts, since the formation of surface-active compounds was decisively influenced by the composition and concentration of the medium components. In the presence of yeast extract, biosurfactant production was poor. For the nitrogen-source nitrate, which was superior to ammonium, an optimum carbon-to-nitrogen ratio of ca. 18 existed. The iron concentration needed to be minimized to 27.5 ..mu..g of FeSO/sub 4/ . 7H/sub 2/O per g of glucose. A carbon-to-phosphate ratio below 16 yielded the maximum production of rhamnolipids. The final productivity dilution rate diagram indicated that biosurfactant production was correlated to low growth rates (dilution rate below 0.15 h/sup -1/). With a medium containing 18.2 g of glucose liter/sup -1/, a biosurfactant concentration (expressed as rhamnolipids) of up to 1.5 g liter/sup -1/ was obtained in the cell-free culture liquid.

  3. Ammonia modification of activated carbon to enhance carbon dioxide adsorption: Effect of pre-oxidation

    NASA Astrophysics Data System (ADS)

    Shafeeyan, Mohammad Saleh; Daud, Wan Mohd Ashri Wan; Houshmand, Amirhossein; Arami-Niya, Arash

    2011-02-01

    A commercial granular activated carbon (GAC) was subjected to thermal treatment with ammonia for obtaining an efficient carbon dioxide (CO2) adsorbent. In general, CO2 adsorption capacity of activated carbon can be increased by introduction of basic nitrogen functionalities onto the carbon surface. In this work, the effect of oxygen surface groups before introduction of basic nitrogen functionalities to the carbon surface on CO2 adsorption capacity was investigated. For this purpose two different approaches of ammonia treatment without preliminary oxidation and amination of oxidized samples were studied. Modified carbons were characterized by elemental analysis and Fourier Transform Infrared spectroscopy (FT-IR) to study the impact of changes in surface chemistry and formation of specific surface groups on adsorption properties. The texture of the samples was characterized by conducting N2 adsorption/desorption at -196 C. CO2 capture performance of the samples was investigated using a thermogravimetric analysis (TGA). It was found that in both modification techniques, the presence of nitrogen functionalities on carbon surface generally increased the CO2 adsorption capacity. The results indicated that oxidation followed by high temperature ammonia treatment (800 C) considerably enhanced the CO2 uptake at higher temperatures.

  4. Adsorption of gold cyanide complexes by activated carbon on non-coconut shell origin

    SciTech Connect

    Yalcin, M.; Arol, A.I.

    1995-12-31

    Coconut shells are the most widely used raw material for the production of activated carbon used in the gold production by cyanide leaching. There have been efforts to find alternatives to coconut shells. Shells and stones of certain fruits, have been tested. Although promising results to some extent were obtained, coconut shells remain the main source of activated carbon. Turkey has become a country of interest in terms of gold deposits of epithermal origin. Four deposits have already been discovered and, mining and milling operations are expected to start in the near future. Explorations are underway in many other areas of high expectations. Turkey is also rich in fruits which can be a valuable source of raw material for activated carbon production. In this study, hazelnut shells, peach and apricot stones, abundantly available locally, have been tested to determine whether they are suitable for the gold metallurgy. Parameters of carbonization and activation have been optimized. Gold loading capacity and adsorption kinetics have been studied.

  5. A General Methodology for Evaluation of Carbon Sequestration Activities and Carbon Credits

    SciTech Connect

    Klasson, KT

    2002-12-23

    A general methodology was developed for evaluation of carbon sequestration technologies. In this document, we provide a method that is quantitative, but is structured to give qualitative comparisons despite changes in detailed method parameters, i.e., it does not matter what ''grade'' a sequestration technology gets but a ''better'' technology should receive a better grade. To meet these objectives, we developed and elaborate on the following concepts: (1) All resources used in a sequestration activity should be reviewed by estimating the amount of greenhouse gas emissions for which they historically are responsible. We have done this by introducing a quantifier we term Full-Cycle Carbon Emissions, which is tied to the resource. (2) The future fate of sequestered carbon should be included in technology evaluations. We have addressed this by introducing a variable called Time-adjusted Value of Carbon Sequestration to weigh potential future releases of carbon, escaping the sequestered form. (3) The Figure of Merit of a sequestration technology should address the entire life-cycle of an activity. The figures of merit we have developed relate the investment made (carbon release during the construction phase) to the life-time sequestration capacity of the activity. To account for carbon flows that occur during different times of an activity we incorporate the Time Value of Carbon Flows. The methodology we have developed can be expanded to include financial, social, and long-term environmental aspects of a sequestration technology implementation. It does not rely on global atmospheric modeling efforts but is consistent with these efforts and could be combined with them.

  6. DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS

    SciTech Connect

    Elliot B. Kennel; Quentin C. Berg; Stephen P. Carpenter; Dady Dadyburjor; Jason C. Hissam; Manoj Katakdaunde; Liviu Magean; Abha Saddawi; Alfred H. Stiller; John W. Zondlo

    2006-03-07

    The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. The largest applications are those which support metals smelting, such as anodes for aluminum smelting and electrodes for arc furnaces. Other carbon products include materials used in creating fuels for the Direct Carbon Fuel Cell, metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. During this reporting period, efforts have focused on the development of carbon electrodes for Direct Carbon Fuel Cells (DCFC), and on carbon foam composites used in ballistic armor, as well as the hydrotreatment of solvents used in the basic solvent extraction process. A major goal is the production of 1500 pounds of binder pitch, corresponding to about 3000 pounds of hydrotreated solvent.

  7. Modified Activated Carbon to be Used in Clinical Applications

    NASA Astrophysics Data System (ADS)

    Fernando, M. S.; de Silva, W. R. M.; de Silva, K. M. N.

    2014-11-01

    In this study a novel nano composite of hydroxyapatite nano particles impregnated activated carbon (C-HAp), which was synthesized in our own method, was used in iron adsorption studies. The study was conducted in order to investigate the potential of using C-HAp nanocomposite to be used in clinical detoxifications such as acute iron toxicity where the use of Activated carbon (GAC) is not very effective. Adsorption studies were conducted for synthetic solutions of Fe2+, Fe3+ and iron syrup using GAC, C-HAp and neat HAp as adsorbents. According to the results C-HAp nano composite showed improved properties than GAC in adsorbing Fe2+, Fe3+ and also Fe ions in iron syrup solutions. Thus the results of the in-vitro studies of iron adsorption studies indicated the potential of using C-HAp as an alternative to activated carbon in such clinical applications.

  8. Chars pyrolyzed from oil palm wastes for activated carbon preparation

    SciTech Connect

    Lua, A.C.; Guo, J.

    1999-01-01

    Chars pyrolyzed from extracted oil palm fibers for the preparation of activated carbons were studied. The effects of pyrolysis temperature and hold time on density, porosity, yield, BET and micropore surface areas, total pore volume, and pore size distributions of chars were investigated. The optimum conditions for pyrolysis were found to be at a pyrolysis temperature of 850 C for a hold time of 3.5 h. Scanning electron micrographs of the char surfaces verified the presence of porosities. The experimental results showed that it was feasible to produce chars with high BET and micropore surface areas from extracted oil palm fibers. The resulting chars will be subjected to steam or carbon dioxide activation to prepare activated carbons for use as gas adsorbents for air pollution control.

  9. Impact of sulfur oxides on mercury capture by activated carbon

    SciTech Connect

    Albert A. Presto; Evan J. Granite

    2007-09-15

    Recent field tests of mercury removal with activated carbon injection (ACI) have revealed that mercury capture is limited in flue gases containing high concentrations of sulfur oxides (SOx). In order to gain a more complete understanding of the impact of SOx on ACI, mercury capture was tested under varying conditions of SO{sub 2} and SO{sub 3} concentrations using a packed bed reactor and simulated flue gas (SFG). The final mercury content of the activated carbons is independent of the SO{sub 2} concentration in the SFG, but the presence of SO{sub 3} inhibits mercury capture even at the lowest concentration tested (20 ppm). The mercury removal capacity decreases as the sulfur content of the used activated carbons increases from 1 to 10%. In one extreme case, an activated carbon with 10% sulfur, prepared by H{sub 2}SO{sub 4} impregnation, shows almost no mercury capacity. The results suggest that mercury and sulfur oxides are in competition for the same binding sites on the carbon surface. 30 refs., 3 figs., 2 tabs.

  10. [Carbon efficiency of double-rice production system in Hunan Province, China].

    PubMed

    Chen, Zhong-du; Wu, Yao; Ti, Jin-song; Chen, Fu; Li, Yong

    2015-01-01

    Improving the carbon efficiency of crop production systems is one of the important ways to realize low-carbon agriculture. A life cycle assessment approach and input-output calculation method was applied for a double-rice production system in the Hunan Province. Based on statistical data of crop yield and investment in the production system in the period from 2004 to 2012, carbon emission, carbon absorption, carbon efficiency and their dynamic changes of the double rice production systems were estimated. The results showed that the average of annual carbon emission from 2004 to 2012 was 656.4 x 10(7) kg CE. Carbon emissions from production and transport of fertilizer and pesticide accounted for a majority of agricultural input carbon emissions, approximately 70.0% and 15.9%, respectively. The carbon emission showed a decreasing trend from 2004 to 2012 in the Hunan Province, with an annual reduction rate of 2.4%, but the carbon emission intensity was in a trend of increase. The average of annual carbon absorption was 1547.0 x 10(7) kg C. The annual carbon absorption also showed a decreasing trend from 2004 to 2012 in Hunan Province, with an average annual reduction rate of 1.2%, and the carbon absorption intensity showed a trend of increase. Furthermore, production efficiency of carbon showed a slow upward trend. The economic efficiency of carbon showed a larger increasing rate with time, with an average annual growth rate of 9.9%. Ecological efficiency of carbon was stable and low, maintained at about 2.4 kg C . kg-1 CE. It indicated that the integrated carbon efficiency of Hunan double rice crop production system improved slowly with time and the key to improve the carbon efficiency of double rice production systems lies in reducing the rates of nitrogen fertilizer and pesticide, and improving their use efficiencies. PMID:25985657

  11. Adsorption of naphthenic acids on high surface area activated carbons.

    PubMed

    Iranmanesh, Sobhan; Harding, Thomas; Abedi, Jalal; Seyedeyn-Azad, Fakhry; Layzell, David B

    2014-01-01

    In oil sands mining extraction, water is an essential component; however, the processed water becomes contaminated through contact with the bitumen at high temperature, and a portion of it cannot be recycled and ends up in tailing ponds. The removal of naphthenic acids (NAs) from tailing pond water is crucial, as they are corrosive and toxic and provide a substrate for microbial activity that can give rise to methane, which is a potent greenhouse gas. In this study, the conversion of sawdust into an activated carbon (AC) that could be used to remove NAs from tailings water was studied. After producing biochar from sawdust by a slow-pyrolysis process, the biochar was physically activated using carbon dioxide (CO2) over a range of temperatures or prior to producing biochar, and the sawdust was chemically activated using phosphoric acid (H3PO4). The physically activated carbon had a lower surface area per gram than the chemically activated carbon. The physically produced ACs had a lower surface area per gram than chemically produced AC. In the adsorption tests with NAs, up to 35mg of NAs was removed from the water per gram of AC. The chemically treated ACs showed better uptake, which can be attributed to its higher surface area and increased mesopore size when compared with the physically treated AC. Both the chemically produced and physically produced AC provided better uptake than the commercially AC. PMID:24766592

  12. DEVELOPMENT OF CARBON PRODUCTS FROM LOW-RANK COALS

    SciTech Connect

    Edwin S. Olson

    2001-07-01

    The goal of this project is to facilitate the production of carbon fibers from low-rank coal (LRC) tars. To this end, the effect of demineralization on the tar yields and composition was investigated using high-sodium and high-calcium lignites commonly mined in North Dakota. These coals were demineralized by ion exchange with ammonium acetate and by cation dissolution with nitric acid. Two types of thermal processing were investigated for obtaining suitable precursors for pitch and fiber production. Initially, tars were produced by simple pyrolysis of the set of samples at 650 C. Since these experiments produced little usable material from any of the samples, the coals were heated at moderate temperatures (380 and 400 C) in tetralin solvent to form and extract the plastic material (metaplast) that forms at these temperatures.

  13. Catalytic carbon membranes for hydrogen production. Final report

    SciTech Connect

    Damle, A.S.; Gangwal, S.K.

    1992-01-01

    Commercial carbon composite microfiltration membranes may be modified for gas separation applications by providing a gas separation layer with pores in the 1- to 10-nm range. Several organic polymeric precursors and techniques for depositing a suitable layer were investigated in this project. The in situ polymerization technique was found to be the most promising, and pure component permeation tests with membrane samples prepared with this technique indicated Knudsen diffusion behavior. The gas separation factors obtained by mixed-gas permeation tests were found to depend strongly on gas temperature and pressure indicating significant viscous flow at high-pressure conditions. The modified membranes were used to carry out simultaneous water gas shift reaction and product hydrogen separation. These tests indicated increasing CO conversions with increasing hydrogen separation. A simple process model was developed to simulate a catalytic membrane reactor. A number of simulations were carried out to identify operating conditions leading to product hydrogen concentrations over 90 percent. (VC)

  14. Spatial Estimation of Timber Production and Carbon in Harvested Wood Products Using Remote Sensing

    NASA Astrophysics Data System (ADS)

    Ling, P. Y.; Baiocchi, G.; Huang, C.

    2014-12-01

    Accurate estimation of the annual production of different kinds of timbers at different locations has many science and policy implications. For example, timber type information is needed for accurate estimation of the amount and life cycle of carbon stored in the harvested wood product (HWP) pool, and possible transport of carbon in wood products through trade. Several attempts have been made to estimate the carbon storage in the HWP, regardless which approach to use, information of the annual timber production are required. A statistic model has been developed to estimate the annual roundwood production at the county level. The inputs of the model includes forest disturbance area calculated using the VCT algorithm derived from the Landsat time series stack, a forest type map, and timber product output (TPO) data collected from wood processing mills by the USFS. The model is applied to North Carolina, a state with a large forestry sector and where harvesting and logging are a primary forest disturbance type. Ten-fold cross validation were done to the preliminary estimation for each type of HWP. The root mean square errors range between 13.6 and 31.5 for hardwood types; and between 1.3 and 55.6 for softwood types. The model is empirical as it depends on the local information on forest disturbance, forest types, and the amount of the roundwood output. However, the approach of the model can be used to apply to other areas with the local information provided. The result can be served as a starting point in spatial estimation of carbon storage in HWP.

  15. Oxygen production and carbon sequestration in an upwelling coastal margin

    NASA Astrophysics Data System (ADS)

    Hales, Burke; Karp-Boss, Lee; Perlin, Alexander; Wheeler, Patricia A.

    2006-09-01

    We examined high-resolution cross-shelf distributions of particulate organic carbon (POC) and dissolved O2 during the upwelling season off the Oregon coast. Oxygen concentrations were supersaturated in surface waters, and hypoxic in near-bottom waters, with greatly expanded hypoxic conditions late in the season. Simplified time-dependent mass balances on cross-shelf integrated concentrations of these two parameters, found the following: (1) The average net rate of photosynthesis generated 2.1 mmol O2 m-3 d-1 and (2) essentially none of the corresponding net carbon fixation of 1.4 mmol m-3 d-1 could be accounted for in the observed standing stocks of POC. After examining other possible sinks for carbon, we conclude that most of the net production is being exported to the adjacent deep ocean. A simplified POC budget suggests that about a quarter of the export is via alongshore advection, and the remainder is due to some other process. We propose a simplistic conceptual model of across-shelf transport in which POC sinks to the bottom boundary layer where it comes into contact with mineral ballast material but is kept in suspension by high turbulence. When upwelling conditions ease, the BBL waters move seaward, carrying the suspended, ballasted POC with it where it sinks rapidly into the deep ocean at the shelf break. This suggests a mechanism whereby the duration and frequency of upwelling events and relaxations can determine the extent to which new carbon produced by photosynthesis in the coastal ocean is exported to depth rather than being respired on the shelf.

  16. Carbon dioxide coordination and activation by niobium oxide molecules.

    PubMed

    Zhou, Mingfei; Zhou, Zijian; Zhuang, Jia; Li, Zhen Hua; Fan, Kangnian; Zhao, Yanying; Zheng, Xuming

    2011-12-22

    Carbon dioxide coordination and activation by niobium oxide molecules were studied by matrix isolation infrared spectroscopy. It was found that the niobium monoxide molecule reacted with carbon dioxide to form the niobium dioxide carbonyl complex NbO(2)(?(1)-CO) spontaneously on annealing in solid neon. The observation of the spontaneous reaction is consistent with theoretical predictions that this carbon dioxide activation process is both thermodynamically exothermic and kinetically facile. In contrast, four niobium dioxide-carbon dioxide complexes exhibiting three different coordination modes of CO(2) were formed from the reactions between niobium dioxide and carbon dioxide, which proceeded with the initial formation of the ?(1)-O bound NbO(2)(?(1)-OCO) and NbO(2)(?(1)-OCO)(2) complexes on annealing. The NbO(2)(?(1)-OCO) complex rearranged to the ?(2)-O,O bound NbO(2)(?(2)-O(2)C) isomer under visible light irradiation, while the NbO(2)(?(1)-OCO)(2) complex isomerized to the NbO(2)(?(1)-OCO)(?(2)-OC)O structure involving an ?(2)-C,O ligand under IR excitation. In these niobium dioxide carbon dioxide complexes, the ?(1)-O coordinated CO(2) ligand serves as an electron donor, whereas both the ?(2)-C,O and ?(2)-O,O coordinated CO(2) ligands act as electron acceptors. PMID:22059436

  17. Removal of benzocaine from water by filtration with activated carbon

    USGS Publications Warehouse

    Howe, G.E.; Bills, T.D.; Marking, L.L.

    1990-01-01

    Benzocaine is a promising candidate for registration with the U.S. Food and Drug Administration for use as an anesthetic in fish culture, management, and research. A method for the removal of benzocaine from hatchery effluents could speed registration of this drug by eliminating requirements for data on its residues, tolerances, detoxification, and environmental hazards. Carbon filtration effectively removes many organic compounds from water. This study tested the effectiveness of three types of activated carbon for removing benzocaine from water by column filtration under controlled laboratory conditions. An adsorptive capacity was calculated for each type of activated carbon. Filtrasorb 400 (12 x 40 mesh; U.S. standard sieve series) showed the greatest capacity for benzocaine adsorption (76.12 mg benzocaine/g carbon); Filtrasorb 300 (8 x 30 mesh) ranked next (31.93 mg/g); and Filtrasorb 816 (8 x 16 mesh) absorbed the least (1.0 mg/g). Increased adsorptive capacity was associated with smaller carbon particle size; however, smaller particle size also impeded column flow. Carbon filtration is a practical means for removing benzocaine from treated water.

  18. Continuous flow thermal desorption of VOC's from activated carbon

    SciTech Connect

    Klobucar, J.M.; Pilat, M.J. )

    1992-02-01

    A countercurrent thermal VOC desorber apparatus with 0.43 to 0.67 lb/hr activated carbon flow and 0.43 to 0.49 scfm purge air flow provided 26.6 to 77.7% VOC desorption efficiency over the 62 to 199 F operating range. The VOC concentration of the carbon was measured at the carbon inlet, outlet, and two intermediate points in the desorber by thermogravimetric analysis. Inlet adsorbent carbon VOC concentrations ranged from 0.23 to 0.44 grams VOC/gram carbon. The VOC concentration of the purge air was measured at the purge air outlet and two points within the desorber by GC-FID. The VOC concentration of the outlet purge air ranged from 14,627 to 44,209 ppm. The VOC concentrations measured in the activated carbon and in the purge air provided the operating line data for plotting on an X-Y diagram and together with the equilibrium isotherms resulted in mass transfer coefficients K{sub g}a in the 472 to 864 lb/ft{sup 3} hr range.

  19. Improved granular activated carbon for the stabilization of wastewater pH

    SciTech Connect

    1996-10-01

    Many times the start up of granular activated carbon adsorption systems for the control of organic contaminants in wastewater cm exhibit unacceptable increases in the adscurber effluent pH. Experience shows that the duration of the pH increase ranges from several hours to several days, during which time several hundred bed volumes of water can be discharged with a pH in excess of 9. Laboratory studies have identified the cause of the pH rise as an interaction between the naturally occurring anions and protons ar the water and the carbon surface. The interaction can be described as an ion exchange type of phenomenon, in which the carbon surface sorbs the anions and corresponding hydronium ions from the water. Capacities of the carbon for the anions range from 2 to 9 mg/g GAC, depending upon the water characteristics, the carbon type, the nature of the anion and its influent concentration. These studies have shown de the anion sorption and resulting pH increase is independent of the raw material used for die activated carbon production, e.g. bituminous or sub-bituminous coal, peat, wood or coconut. Also, the pH excursions occur with virgin, reactivated, and acid washed granular carbons. Current pH control technologies focus on adjustment of wastewater pH prior to discharge or recycle of the initial effluent water until the pH increase abates. However, improved water pH control options have been realized by altering the carbon surface rather than the water chemistry. The change to the carbon surface is accomplished through a controlled oxidation process. This process provides a more acidic carbon surface with a reduced affinity for the anions in the waste water. As a result, the pH excursions above 9 are eliminated and the initial effluent from the adsorption system can be discharged without further treatment.

  20. Burners and combustion apparatus for carbon nanomaterial production

    DOEpatents

    Alford, J. Michael; Diener, Michael D.; Nabity, James; Karpuk, Michael

    2007-10-09

    The invention provides improved burners, combustion apparatus, and methods for carbon nanomaterial production. The burners of the invention provide sooting flames of fuel and oxidizing gases. The condensable products of combustion produced by the burners of this invention produce carbon nanomaterials including without limitation, soot, fullerenic soot, and fullerenes. The burners of the invention do not require premixing of the fuel and oxidizing gases and are suitable for use with low vapor pressure fuels such as those containing substantial amounts of polyaromatic hydrocarbons. The burners of the invention can operate with a hot (e.g., uncooled) burner surface and require little, if any, cooling or other forms of heat sinking. The burners of the invention comprise one or more refractory elements forming the outlet of the burner at which a flame can be established. The burners of the invention provide for improved flame stability, can be employed with a wider range of fuel/oxidizer (e.g., air) ratios and a wider range of gas velocities, and are generally more efficient than burners using water-cooled metal burner plates. The burners of the invention can also be operated to reduce the formation of undesirable soot deposits on the burner and on surfaces downstream of the burner.

  1. Burners and combustion apparatus for carbon nanomaterial production

    DOEpatents

    Alford, J. Michael; Diener, Michael D; Nabity, James; Karpuk, Michael

    2013-02-05

    The invention provides improved burners, combustion apparatus, and methods for carbon nanomaterial production. The burners of the invention provide sooting flames of fuel and oxidizing gases. The condensable products of combustion produced by the burners of this invention produce carbon nanomaterials including without limitation, soot, fullerenic soot, and fullerenes. The burners of the invention do not require premixing of the fuel and oxidizing gases and are suitable for use with low vapor pressure fuels such as those containing substantial amounts of polyaromatic hydrocarbons. The burners of the invention can operate with a hot (e.g., uncooled) burner surface and require little, if any, cooling or other forms of heat sinking. The burners of the invention comprise one or more refractory elements forming the outlet of the burner at which a flame can be established. The burners of the invention provide for improved flame stability, can be employed with a wider range of fuel/oxidizer (e.g., air) ratios and a wider range of gas velocities, and are generally more efficient than burners using water-cooled metal burner plates. The burners of the invention can also be operated to reduce the formation of undesirable soot deposits on the burner and on surfaces downstream of the burner.

  2. Carbon-based Supercapacitors Produced by Activation of Graphene

    SciTech Connect

    Y Zhu; S Murali; M Stoller; K Ganesh; W Cai; P Ferreira; A Pirkle; R Wallace; K Cychosz; et al.

    2011-12-31

    Supercapacitors, also called ultracapacitors or electrochemical capacitors, store electrical charge on high-surface-area conducting materials. Their widespread use is limited by their low energy storage density and relatively high effective series resistance. Using chemical activation of exfoliated graphite oxide, we synthesized a porous carbon with a Brunauer-Emmett-Teller surface area of up to 3100 square meters per gram, a high electrical conductivity, and a low oxygen and hydrogen content. This sp{sup 2}-bonded carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form primarily 0.6- to 5-nanometer-width pores. Two-electrode supercapacitor cells constructed with this carbon yielded high values of gravimetric capacitance and energy density with organic and ionic liquid electrolytes. The processes used to make this carbon are readily scalable to industrial levels.

  3. Carbon-Based Supercapacitors Produced by Activation of Graphene

    SciTech Connect

    Zhu, Y.; Su, D.; Murali, S.; Stoller, M.D.; Ganesh, K.J.; Cai, W.; Ferreira, P.J.; Pirkle, A.; Wallace, R.M.; Cychosz, K.A., Thommes, M.; Stach, E.A.; Ruoff, R.S.

    2011-06-24

    Supercapacitors, also called ultracapacitors or electrochemical capacitors, store electrical charge on high-surface-area conducting materials. Their widespread use is limited by their low energy storage density and relatively high effective series resistance. Using chemical activation of exfoliated graphite oxide, we synthesized a porous carbon with a Brunauer-Emmett-Teller surface area of up to 3100 square meters per gram, a high electrical conductivity, and a low oxygen and hydrogen content. This sp{sup 2}-bonded carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form primarily 0.6- to 5-nanometer-width pores. Two-electrode supercapacitor cells constructed with this carbon yielded high values of gravimetric capacitance and energy density with organic and ionic liquid electrolytes. The processes used to make this carbon are readily scalable to industrial levels.

  4. Removing lead in drinking water with activated carbon

    SciTech Connect

    Taylor, R.M.; Kuennen, R.W. )

    1994-02-01

    A point-of-use (POU) granular activated carbon (GAC) fixed bed adsorber (FBA) was evaluated for reduction of soluble and insoluble lead from drinking water. Some of the factors which affect lead removal by GAC were evaluated, such as carbon type, solution pH, and a limited amount of work on competitive interactions. The design criteria for lead reduction by a POU device are also addressed. Minicolumns were used to evaluate the capacity of carbon for lead under a variety of conditions. The importance of surface chemistry of the carbon and the relationship with the pH of the water for lead reduction was demonstrated. Results indicate that a properly designed POU-GAC-FBA can reduce lead in drinking water to below the EPA action level of 15 ppb while being tested under a variety of conditions as specified under the National Sanitation Foundation (NSF) International Standard 53 test protocol. 37 refs., 9 figs., 1 tab.

  5. Pore structure of the activated coconut shell charcoal carbon

    NASA Astrophysics Data System (ADS)

    Budi, E.; Nasbey, H.; Yuniarti, B. D. P.; Nurmayatri, Y.; Fahdiana, J.; Budi, A. S.

    2014-09-01

    The development of activated carbon from coconut shell charcoal has been investigated by using physical method to determine the influence of activation parameters in term of temperature, argon gas pressure and time period on the pore structure of the activated carbon. The coconut shell charcoal was produced by pyrolisis process at temperature of about 75 - 150 °C for 6 hours. The charcoal was activated at various temperature (532, 700 and 868 °C), argon gas pressure (6.59, 15 and 23.4 kgf/cm2) and time period of (10, 60 and 120 minutes). The results showed that the pores size were reduced and distributed uniformly as the activation parameters are increased.

  6. Gel nanostructure in alkali-activated binders based on slag and fly ash, and effects of accelerated carbonation

    SciTech Connect

    Bernal, Susan A.; Provis, John L.; Walkley, Brant; San Nicolas, Rackel; Gehman, John D.; Brice, David G.; Kilcullen, Adam R.; Zeobond Pty Ltd, P.O. Box 23450, Docklands, Victoria 8012 ; Duxson, Peter; Deventer, Jannie S.J. van

    2013-11-15

    Binders formed through alkali-activation of slags and fly ashes, including ‘fly ash geopolymers’, provide appealing properties as binders for low-emissions concrete production. However, the changes in pH and pore solution chemistry induced during accelerated carbonation testing provide unrealistically low predictions of in-service carbonation resistance. The aluminosilicate gel remaining in an alkali-activated slag system after accelerated carbonation is highly polymerised, consistent with a decalcification mechanism, while fly ash-based binders mainly carbonate through precipitation of alkali salts (bicarbonates at elevated CO{sub 2} concentrations, or carbonates under natural exposure) from the pore solution, with little change in the binder gel identifiable by nuclear magnetic resonance spectroscopy. In activated fly ash/slag blends, two distinct gels (C–A–S–H and N–A–S–H) are formed; under accelerated carbonation, the N–A–S–H gel behaves comparably to fly ash-based systems, while the C–A–S–H gel is decalcified similarly to alkali-activated slag. This provides new scope for durability optimisation, and for developing appropriate testing methodologies. -- Highlights: •C-A-S-H gel in alkali-activated slag decalcifies during accelerated carbonation. •Alkali-activated fly ash gel changes much less under CO{sub 2} exposure. •Blended slag-fly ash binder contains two coexisting gel types. •These two gels respond differently to carbonation. •Understanding of carbonation mechanisms is essential in developing test methods.

  7. Anaerobic degradation of phenol and bioregeneration of granular activated carbon

    SciTech Connect

    Craveiro de Sa, Fernando Antonio.

    1991-01-01

    The objectives of this research included evaluation and comparison of the occurrence of the biological removal of phenol adsorbed onto granular activated carbon (GAC), under anaerobic methanogenic conditions, and at different phenol gradients between the GAC and the bulk liquid. The scope included monitoring the degradation of radiolabeled phenol and production of radiolabeled methane in three column reactors operated in parallel under different gradients of phenol. Three columns were operated in semi-continuous mode at 35C. GAC was pre-loaded with radiolabeled phenol at an equilibrium concentration of approximately 100 mg/L. During Phase 1, phenol was fed daily at dosages that (a) increased the phenol concentration, (b) maintained approximately constant, and (c) decreased the phenol concentration, respectively in each of the three columns to establish different gradients between GAC and bulk liquid. The feeding scheme was reversed for Phase 2 in each of the columns. Conventional bottle-point procedures and desorption procedures were used to develop isotherms under anaerobic conditions.

  8. Transition metal activation and functionalization of carbon-hydrogen bonds

    SciTech Connect

    Jones, W.D.

    1992-06-01

    We are investigating the fundamental thermodynamic and kinetic factors that influence carbon-hydrogen bond activation at homogeneous transition metal centers and the conversion of hydrocarbons into functionalized products of potential use to the chemical industry. Advances have been made in both understanding the interactions of hydrocarbons with metals and in the functionalization of hydrocarbons. We have found that RhCl(PR{sub 3}){sub 2}(CNR) complexes can catalyze the insertion of isonitriles into the C-H bonds or arenes upon photolysis. The mechanism of these reactions was found to proceed by way of initial phosphine dissociation, followed by C-H activation and isonitrile insertion. We have also examined reactions of a series of arenes with (C{sub 5}Me{sub 5})Rh(PMe{sub 3})PhH and begun to map out the kinetic and thermodynamic preferences for arene coordination. The effects of resonance, specifically the differences in the Hueckel energies of the bound vs free ligand, are now believed to fully control the C-H activation/{eta}{sup 2}-coordination equilibria. We have begun to examine the reactions of rhodium isonitrile pyrazolylborates for alkane and arene C-H bond activation. A new, labile, carbodiimide precursor has been developed for these studies. We have completed studies of the reactions of (C{sub 5}Me{sub 5})Rh(PMe{sub 3})H{sub 2} with D{sub 2} and PMe{sub 3} that indicate that both {eta}{sup 5} {yields} {eta}{sup 3} ring slippage and metal to ring hydride migration occur more facilely than thermal reductive elimination of H{sub 2}. We have examined the reactions of heterocycles with (C{sub 5}Me{sub 5})Rh(PMe{sub 3})PhH and found that pyrrole and furan undergo C-H or N-H activation. Thiophene, however, undergoes C-S bond oxidative addition, and the mechanism of activation has been shown to proceed through sulfur coordination prior to C-S insertion.

  9. Phytoplankton Productivity in an Arctic Fjord (West Greenland): Estimating Electron Requirements for Carbon Fixation and Oxygen Production.

    PubMed

    Hancke, Kasper; Dalsgaard, Tage; Sejr, Mikael Kristian; Markager, Stiig; Glud, Ronnie Nhr

    2015-01-01

    Accurate quantification of pelagic primary production is essential for quantifying the marine carbon turnover and the energy supply to the food web. Knowing the electron requirement (?) for carbon (C) fixation (?C) and oxygen (O2) production (?O2), variable fluorescence has the potential to quantify primary production in microalgae, and hereby increasing spatial and temporal resolution of measurements compared to traditional methods. Here we quantify ?C and ?O2 through measures of Pulse Amplitude Modulated (PAM) fluorometry, C fixation and O2 production in an Arctic fjord (Godthbsfjorden, W Greenland). Through short- (2h) and long-term (24h) experiments, rates of electron transfer (ETRPSII), C fixation and/or O2 production were quantified and compared. Absolute rates of ETR were derived by accounting for Photosystem II light absorption and spectral light composition. Two-hour incubations revealed a linear relationship between ETRPSII and gross 14C fixation (R2 = 0.81) during light-limited photosynthesis, giving a ?C of 7.6 0.6 (mean S.E.) mol (mol C)-1. Diel net rates also demonstrated a linear relationship between ETRPSII and C fixation giving a ?C of 11.2 1.3 mol (mol C)-1 (R2 = 0.86). For net O2 production the electron requirement was lower than for net C fixation giving 6.5 0.9 mol (mol O2)-1 (R2 = 0.94). This, however, still is an electron requirement 1.6 times higher than the theoretical minimum for O2 production [i.e. 4 mol (mol O2)-1]. The discrepancy is explained by respiratory activity and non-photochemical electron requirements and the variability is discussed. In conclusion, the bio-optical method and derived electron requirement support conversion of ETR to units of C or O2, paving the road for improved spatial and temporal resolution of primary production estimates. PMID:26218096

  10. Atypical Hydrogen Uptake on Chemically Activated, Ultramicroporous Carbon

    SciTech Connect

    Bhat, Vinay V; Contescu, Cristian I; Gallego, Nidia C; Baker, Frederick S

    2010-01-01

    Hydrogen adsorption at near-ambient temperatures on ultramicroporous carbon (UMC), derived through secondary chemical activation from a wood-based activated carbon was studied using volumetric and gravimetric methods. The results showed that physisorption is accompanied by a process of different nature that causes slow uptake at high pressures and hysteresis on desorption. In combination, this results in unusually high levels of hydrogen uptake at near-ambient temperatures and pressures (e.g. up to 0.8 wt % at 25 oC and 2 MPa). The heat of adsorption corresponding to the slow process leading to high uptake (17 20 kJ/mol) is higher than usually reported for carbon materials, but the adsorption kinetics is slow, and the isotherms exhibit pronounced hysteresis. These unusual properties were attributed to contributions from polarization-enhanced physisorption caused by traces of alkali metals residual from chemical activation. The results support the hypothesis that polarization-induced physisorption in high surface area carbons modified with traces of alkali metal ions is an alternate route for increasing the hydrogen storage capacity of carbon adsorbents.

  11. Carbon footprint of Canadian dairy products: calculations and issues.

    PubMed

    Vergé, X P C; Maxime, D; Dyer, J A; Desjardins, R L; Arcand, Y; Vanderzaag, A

    2013-09-01

    The Canadian dairy sector is a major industry with about 1 million cows. This industry emits about 20% of the total greenhouse gas (GHG) emissions from the main livestock sectors (beef, dairy, swine, and poultry). In 2006, the Canadian dairy herd produced about 7.7 Mt of raw milk, resulting in about 4.4 Mt of dairy products (notably 64% fluid milk and 12% cheese). An integrated cradle-to-gate model (field to processing plant) has been developed to estimate the carbon footprint (CF) of 11 Canadian dairy products. The on-farm part of the model is the Unified Livestock Industry and Crop Emissions Estimation System (ULICEES). It considers all GHG emissions associated with livestock production but, for this study, it was run for the dairy sector specifically. Off-farm GHG emissions were estimated using the Canadian Food Carbon Footprint calculator, (cafoo)(2)-milk. It considers GHG emissions from the farm gate to the exit gate of the processing plants. The CF of the raw milk has been found lower in western provinces [0.93 kg of CO2 equivalents (CO2e)/L of milk] than in eastern provinces (1.12 kg of CO2e/L of milk) because of differences in climate conditions and dairy herd management. Most of the CF estimates of dairy products ranged between 1 and 3 kg of CO2e/kg of product. Three products were, however, significantly higher: cheese (5.3 kg of CO2e/kg), butter (7.3 kg of CO2e/kg), and milk powder (10.1 kg of CO2e/kg). The CF results depend on the milk volume needed, the co-product allocation process (based on milk solids content), and the amount of energy used to manufacture each product. The GHG emissions per kilogram of protein ranged from 13 to 40 kg of CO2e. Two products had higher values: cream and sour cream, at 83 and 78 kg of CO2e/kg, respectively. Finally, the highest CF value was for butter, at about 730 kg of CO2e/kg. This extremely high value is due to the fact that the intensity indicator per kilogram of product is high and that butter is almost exclusively fat. Protein content is often used to compare the CF of products; however, this study demonstrates that the use of a common food component is not suitable as a comparison unit in some cases. Functionality has to be considered too, but it might be insufficient for food product labeling because different reporting units (adapted to a specific food product) will be used, and the resulting confusion could lead consumers to lose confidence in such labeling. Therefore, simple units might not be ideal and a more comprehensive approach will likely have to be developed. PMID:23831091

  12. Harnessing the Biological Activity of Natural Products

    Cancer.gov

    Researchers have been intrigued by the potent and beneficial biological activity shown by some natural products and are testing ways to incorporate them into standard and experimental cancer treatment regimens, both to enhance the anticancer effects of therapy and reduce side effects.

  13. Miocene Global Carbon Isotope Shifts and Marine Biological Productivity.

    NASA Astrophysics Data System (ADS)

    Diester-Haass, L.; Billups, K.

    2005-12-01

    The Miocene contains two major global carbon isotope shifts: a negative shift during the late Miocene (~8-6 Ma) and a positive shift during the mid-Miocene (16-14 Ma). We aim at deciphering possible changes in marine biological export productivity during these shifts by calculating paleoproductivity in gC/cm*ky from benthic foraminiferal numbers and accumulation rates at a number of sites spanning the world oceans. Our previous work has illustrated that the onset of the late Miocene negative d 13C shift, which has been attributed to enhanced erosion of terrestrial biomass and expansion of C4 plants, is also accompanied by an increase in marine export productivity from lower than present day values up to 2-3 times modern values at six sites (982, 1088, 721, 846, 1146, 1172; Diester-Haass et al, in press; Diester-Haass et al., in preparation). The Mid-Miocene 'Monterey Event', on the other hand, has been attributed to sequestration of organic material in circum-Pacific basins (Vincent and Berger, 1985) or wide spread deposition of brown coal and drowning of carbonate platforms (Fllmi et al., 2005) . For this particular time interval, our initial results from Site 608 (Atlantic Ocean) reveal relatively constant paleoproductivity values similar to modern ones ( about 10 gC/cm*ky) until 16.5 Ma, after which time paleoproductivity begins to increase until the end of our record at 11 Ma. Superimposed on the trend of generally increasing productivity, there are a number of productivity minima spaced roughly 0.5 million years apart. The long term trend in the paleoproductivity finds some similarities in the global composite benthic foraminiferal d 13C record as both proxies show an overall increase until ~14 Ma. Thereafter, however, paleoproductivity continues to increase while d 13C values decrease marking the end of the Monterey excursion. Stable isotope analyses from these same intervals will show to what extend the smaller scale fluctuations in paleoproductivity can be related to changes in the d13C of the oceanic reservoir or regional water masses. Diester-Haass, L., Billups, K., Emeis, K-C., 2005, Paleoceanography, in press. Vincent, E. and Berger, W., 1985, In: The carbon cycle and atmospheric CO2: Natural variations Archaen to present, edited by Sunquist, E.T. and Broecker, W.S., Am.Geophys. Union Monogr. 32,455-468 Fllmi, K.B. et al., 2005, Geol.Soc.Am.Bull., 117/5, 589-619.

  14. Managing Commercial Tree Species for Timber Production and Carbon Sequestration: Management Guidelines and Financial Returns

    SciTech Connect

    Gary D. Kronrad

    2006-09-19

    A carbon credit market is developing in the United States. Information is needed by buyers and sellers of carbon credits so that the market functions equitably and efficiently. Analyses have been conducted to determine the optimal forest management regime to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. Because the potential of a forest ecosystem to sequester carbon depends on the tree species, site quality and management regimes utilized, analyses have determined how to optimize carbon sequestration by determining how to optimally manage each species, given a range of site qualities, discount rates, prices of carbon credits and other economic variables. The effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, the amount of carbon that can be sequestered, and the amount of timber products produced has been determined.

  15. Removal of steroid estrogens from wastewater using granular activated carbon: comparison between virgin and reactivated carbon.

    PubMed

    Rowsell, Victoria Francesca; Pang, Dawn Sok Cheng; Tsafou, Foteini; Voulvoulis, Nikolaos

    2009-04-01

    This research was set up in response to new European legislation to identify cost-effective treatment for removal of steroid estrogens from effluent. This study aimed to compare estrogen removal of two types of granular activated carbon: virgin (F400) and reactivated (C401) carbon. Rapid, small-scale column tests were conducted with a total bed volume of 24.9 cm3 over three columns, and analysis was carried out using high-performance liquid chromatography. Results demonstrated that C401 performed more efficiently with greater than or equal to 81% estrogen removal in wastewater compared to F400 which produced greater than or equal to 65% estrogen removal. Estrogen removal can be affected by competitive adsorption from natural organic matter present in wastewater. In addition, the physical properties of each carbon had the potential to influence adsorption differently, thus resulting in the observed varied adsorption capability of the two carbons. PMID:19445328

  16. Carboncarbon bond activation of cyclobutenones enabled by the addition of chiral organocatalyst to ketone

    PubMed Central

    Li, Bao-Sheng; Wang, Yuhuang; Jin, Zhichao; Zheng, Pengcheng; Ganguly, Rakesh; Chi, Yonggui Robin

    2015-01-01

    The activation of carboncarbon (CC) bonds is an effective strategy in building functional molecules. The CC bond activation is typically accomplished via metal catalysis, with which high levels of enantioselectivity are difficult to achieve due to high reactivity of metal catalysts and the metal-bound intermediates. It remains largely unexplored to use organocatalysis for CC bond activation. Here we describe an organocatalytic activation of CC bonds through the addition of an NHC to a ketone moiety that initiates a CC single bond cleavage as a key step to generate an NHC-bound intermediate for chemo- and stereo-selective reactions. This reaction constitutes an asymmetric functionalization of cyclobutenones using organocatalysts via a CC bond activation process. Structurally diverse and multicyclic compounds could be obtained with high optical purities via an atom and redox economic process. PMID:25652912

  17. Climate change, carbon dioxide, and global crop production: Adaptation to uncertainty

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Documented and projected changes in atmospheric carbon dioxide are likely to alter agricultural productivity in two ways: directly, by supplying additional carbon for photosynthesis and growth, and indirectly by altering climate, specifically surface temperatures and precipitation. In this overview...

  18. Sum Product Networks for Activity Recognition.

    PubMed

    Amer, Mohamed R; Todorovic, Sinisa

    2016-04-01

    This paper addresses detection and localization of human activities in videos. We focus on activities that may have variable spatiotemporal arrangements of parts, and numbers of actors. Such activities are represented by a sum-product network (SPN). A product node in SPN represents a particular arrangement of parts, and a sum node represents alternative arrangements. The sums and products are hierarchically organized, and grounded onto space-time windows covering the video. The windows provide evidence about the activity classes based on the Counting Grid (CG) model of visual words. This evidence is propagated bottom-up and top-down to parse the SPN graph for the explanation of the video. The node connectivity and model parameters of SPN and CG are jointly learned under two settings, weakly supervised, and supervised. For evaluation, we use our new Volleyball dataset, along with the benchmark datasets VIRAT, UT-Interactions, KTH, and TRECVID MED 2011. Our video classification and activity localization are superior to those of the state of the art on these datasets. PMID:26390445

  19. DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS

    SciTech Connect

    Elliot B. Kennel; Chong Chen; Dady Dadyburjor; Liviu Magean; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

    2005-04-13

    The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. These carbon products include materials used in metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. Table 1 provides an overview of the major markets for carbon products. Current sources of materials for these processes generally rely on petroleum distillation products or coal tar distillates obtained as a byproduct of metcoke production facilities. In the former case, the American materials industry, just as the energy industry, is dependent upon foreign sources of petroleum. In the latter case, metcoke production is decreasing every year due to the combined difficulties associated with poor economics and a significant environmental burden. Thus, a significant need exists for an environmentally clean process which can used domestically obtained raw materials and which can still be very competitive economically.

  20. Antiviral and virucidal activities of natural products.

    PubMed

    Arakawa, Tsutomu; Yamasaki, Hisashi; Ikeda, Keiko; Ejima, Daisuke; Naito, Takeshi; Koyama, A Hajime

    2009-01-01

    Virus infection is one of the major threats to human health and can be avoided by minimizing exposure to infectious viruses. Viral clearance of pharmaceutical products and sanitization of skin and mucosal surfaces would reduce such exposures. Even with such care, virus infection does occur, requiring effective treatments by antiviral or virucidal agents. Natural products, in particular ingredients of foods and drinks we normally consume or metabolites present in human body at low concentrations, would have advantage over synthetic drugs as antiviral agents for safety concerns. For this reason, we have been studying natural products for their effects on virus inactivation and growth. Such natural products, which we have been focusing, include gallate derivatives, caffeine present in coffee, caffeic acid present in coffee and various fruits, ascorbic and dehydroascorbic acids and a cell metabolite, arginine. Here we will review our work on antiviral and virucidal activities of these compounds and the mechanism of their antiviral and virucidal effects. PMID:19601794

  1. 40 CFR 60.1820 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... activated carbon? 60.1820 Section 60.1820 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, you must meet three requirements: (a) Select a carbon injection system...

  2. Activated carbon coated palygorskite as adsorbent by activation and its adsorption for methylene blue.

    PubMed

    Zhang, Xianlong; Cheng, Liping; Wu, Xueping; Tang, Yingzhao; Wu, Yucheng

    2015-07-01

    An activation process for developing the surface and porous structure of palygorskite/carbon (PG/C) nanocomposite using ZnCl2 as activating agent was investigated. The obtained activated PG/C was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (SEM), and Brunauer-Emmett-Teller analysis (BET) techniques. The effects of activation conditions were examined, including activation temperature and impregnation ratio. With increased temperature and impregnation ratio, the collapse of the palygorskite crystal structure was found to accelerate and the carbon coated on the surface underwent further carbonization. XRD and SEM data confirmed that the palygorskite structure was destroyed and the carbon structure was developed during activation. The presence of the characteristic absorption peaks of CC and C-H vibrations in the FTIR spectra suggested the occurrence of aromatization. The BET surface area improved by more than 11-fold (1201 m2/g for activated PG/C vs. 106 m2/g for PG/C) after activation, and the material appeared to be mainly microporous. The maximum adsorption capacity of methylene blue onto the activated PG/C reached 351 mg/g. The activated PG/C demonstrated better compressive strength than activated carbon without palygorskite clay. PMID:26141882

  3. 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. PMID:25531980

  4. Trihalomethane formation potential of aquatic and terrestrial fulvic and humic acids: Sorption on activated carbon.

    PubMed

    Abouleish, Mohamed Y Z; Wells, Martha J M

    2015-07-15

    Humic substances (HSs) are precursors for the formation of hazardous disinfection by-products (DBPs) during chlorination of water. Various surrogate parameters have been used to investigate the generation of DBPs by HS precursors and the removal of these precursors by activated carbon treatment. Dissolved organic carbon (DOC)- and ultraviolet absorbance (UVA254)-based isotherms are commonly reported and presumed to be good predictors of the trihalomethane formation potential (THMFP). However, THMFP-based isotherms are rarely published such that the three types of parameters have not been compared directly. Batch equilibrium experiments on activated carbon were used to generate constant-initial-concentration sorption isotherms for well-characterized samples obtained from the International Humic Substances Society (IHSS). HSs representing type (fulvic acid [FA], humic acid [HA]), origin (aquatic, terrestrial), and geographical source (Nordic, Suwannee, Peat, Soil) were examined at pH6 and pH9. THMFP-based isotherms were generated and compared to determine if DOC- and UVA254-based isotherms were good predictors of the THMFP. The sorption process depended on the composition of the HSs and the chemical nature of the activated carbon, both of which were influenced by pH. Activated carbon removal of THM-precursors was pH- and HS-dependent. In some instances, the THMFP existed after UVA254 was depleted. PMID:25847173

  5. Fine Milling and Mechanochemical Activation of Mine Wastes for Enhanced CO2 Mineral Carbonation

    NASA Astrophysics Data System (ADS)

    Hitch, M.; Li, J.; Dipple, G. M.

    2013-12-01

    Mechanical activation is an effective method to enhancing the physical architecture of mineral grains for mineral carbonation and CO2 sequestration. The advantage of this level of comminution is the disruption of the mineral structure and increase its reactivity. This paper discusses mechanochemical activation of whole rock tailings and compares three grinding methods (stirred, planetary and vibratory mills). Physical characteristics influencing CO2 mineral carbonation were measured using gas adsorption, infrared spectroscopy (FTIR) scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal gravity analysis (TGA). Results to date have indicated that indeed the mechanochemical activation leads to microstructure, structural and chemical changes of mixtures during high-energy milling. Direct aqueous mineral carbonation helped guide the author to the most effective mineral preparation method. Finally, Reitvelt analysis was used for quantitative analysis of the carbonate product. It was found that the activation mode controls the physio-chemical efficacy of the mine waste particle and was responsible for the differences in carbonate conversion.

  6. Effect of dissolved carbon dioxide on penicillin fermentations: mycelial growth and penicillin production. [Penicillium chrysogenum

    SciTech Connect

    Ho, C.S.; Smith, M.D.

    1986-01-01

    The effect of dissolved carbon dioxide on the specific growth rate and the penicillin production rate of Penicillium chrysogenum was examined experimentally. The dissolved carbon dioxide was found to inhibit the specific growth rate and the penicillin production rate when the aerated submerged penicillin fermentation was exposed to influent gases of 12.6 and 20% carbon dioxide, respectively. Upon exposure to influent gases of 3 and 5% carbon dioxide, no pronounced metabolic inhibition was noted.

  7. SUPERCRITICAL FLUID REGENERATION OF ACTIVATED CARBON FOR ADSORPTION OF PESTICIDES

    EPA Science Inventory

    The report describes the development of a new process for regenerating activated carbon, using supercritical CO2 as a desorbent. Supercritical CO2 in the range of 30-250 C and at pressures > 80 atm. is a good solvent for organics. A series of pesticides was tested for treatment b...

  8. Acoustical Evaluation of Carbonized and Activated Cotton Nonwovens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An activated carbon fiber nonwoven (ACF) was manufactured from cotton nonowoven fabric. For the ACF acoustical application, a nonwoven composite of ACF with cotton nonwoven as a base layer was developed. Also produced were the composites of the cotton nonwoven base layer with a layer of glass fiber ...

  9. GAC (GRANULAR ACTIVATED CARBON) TREATMENT COSTS: A SENSITIVITY ANALYSIS

    EPA Science Inventory

    Although admittedly effective for removing organic compounds, concerns have been raised about the cost of using GAC for treating drinking water. This paper is devoted to the discussion of the cost of granular activated carbon for removing organic compounds from drinking water. Ac...

  10. EVALUATION OF P