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  1. Poly(amidoamine) dendrimers show carbonic anhydrase inhibitory activity against α-, β-, γ- and η-class enzymes.

    PubMed

    Carta, Fabrizio; Osman, Sameh M; Vullo, Daniela; AlOthman, Zeid; Del Prete, Sonia; Capasso, Clemente; Supuran, Claudiu T

    2015-11-01

    Four generations of poly(amidoamine) (PAMAM) dendrimers incorporating benzenesulfonamide moieties were investigated as inhibitors of carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the α-, β-, γ- and η-classes which are present in pathogenic bacteria, fungi or protozoa. The following bacterial, fungal and protozoan organisms were included in the study: Vibrio cholerae, Trypanosoma cruzi, Leishmania donovani chagasi, Porphyromonas gingivalis, Cryptococcus neoformans, Candida glabrata, and Plasmodium falciparum. The eight pathozymes present in these organisms were efficiently inhibited by the four generations PAMAM-sulfonamide dendrimers, but multivalency effects were highly variable among the different enzyme classes. The Vibrio enzyme VchCA was best inhibited by the G3 dendrimer incorporating 32 sulfamoyl moieties. The Trypanosoma enzyme TcCA on the other hand was best inhibited by the first generation dendrimer G0 (with 4 sulfamoyl groups), whereas for other enzymes the optimal inhibitory power was observed for the G1 or G2 dendrimers, with 8 and 16 sulfonamide functionalities. This study thus proves that the multivalency may be highly relevant for enzyme inhibition for some but not all CAs from pathogenic organisms. On the other hand, some dendrimers investigated here showed a better inhibitory power compared to acetazolamide for enzymes from widespread pathogens, such as the η-CA from Plasmodium falciparum. Overall, the main conclusion is that this class of molecules may lead to important developments in the field of anti-infective CA inhibitors.

  2. Surveys show support for green 'activities'.

    PubMed

    Baillie, Jonathan

    2012-03-01

    Two independently conducted surveys on sustainability - one into the 'views and values' of NHS 'leaders', and the other questioning the public about the importance of the 'green agenda' in the NHS, and their opinions on how the service might most effectively reduce its carbon footprint, form the basis of Sustainability in the NHS: Health Check 2012, a new NHS Sustainable Development Unit (NHS SDU) publication. As HEJ editor Jonathan Baillie reports, the new document also presents updated data on the 'size' of the carbon footprint of the NHS in England, showing that, although good work by a number of Trusts in the past two years has seen healthcare-generated carbon emissions start to 'level off', the biggest contributors have been the current health service spending review, and the increased national availability of renewable energy.

  3. 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).

  4. Tetrahydrobiopterin shows chaperone activity for tyrosine hydroxylase.

    PubMed

    Thöny, Beat; Calvo, Ana C; Scherer, Tanja; Svebak, Randi M; Haavik, Jan; Blau, Nenad; Martinez, Aurora

    2008-07-01

    Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of catecholamine neurotransmitters. Primary inherited defects in TH have been associated with l-DOPA responsive and non-responsive dystonia and infantile parkinsonism. In this study, we show that both the cofactor (6R)-l-erythro-5,6,7,8-tetrahydrobiopterin (BH(4)) and the feedback inhibitor and catecholamine product dopamine increase the kinetic stability of human TH isoform 1 in vitro. Activity measurements and synthesis of the enzyme by in vitro transcription-translation revealed a complex regulation by the cofactor including both enzyme inactivation and conformational stabilization. Oral BH(4) supplementation to mice increased TH activity and protein levels in brain extracts, while the Th-mRNA level was not affected. All together our results indicate that the molecular mechanisms for the stabilization are a primary folding-aid effect of BH(4) and a secondary effect by increased synthesis and binding of catecholamine ligands. Our results also establish that orally administered BH(4) crosses the blood-brain barrier and therapeutic regimes based on BH(4) supplementation should thus consider the effect on TH. Furthermore, BH(4) supplementation arises as a putative therapeutic agent in the treatment of brain disorders associated with TH misfolding, such as for the human TH isoform 1 mutation L205P.

  5. 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.

  6. Serving Up Activities for TV Cooking Shows.

    ERIC Educational Resources Information Center

    Katchen, Johanna E.

    This paper documents a presentation given on the use of English-language television cooking shows in English-as-a-Second-Language (ESL) and English-as-a-Foreign-Language (EFL) classrooms in Taiwan. Such shows can be ideal for classroom use, since they have a predictable structure consisting of short segments, are of interest to most students,…

  7. Double polymer sheathed carbon nanotube supercapacitors show enhanced cycling stability

    NASA Astrophysics Data System (ADS)

    Zhao, Wenqi; Wang, Shanshan; Wang, Chunhui; Wu, Shiting; Xu, Wenjing; Zou, Mingchu; Ouyang, An; Cao, Anyuan; Li, Yibin

    2015-12-01

    Pseudo-materials are effective in boosting the specific capacitance of supercapacitors, but during service their degradation may also be very strong, causing reduced cycling stability. Here, we show that a carbon nanotube sponge grafted by two conventional pseudo-polymer layers in sequence can serve as a porous supercapacitor electrode with significantly enhanced cycling stability compared with single polymer grafting. Creating conformal polymer coatings on the nanotube surface and the resulting double-sheath configuration are important structural factors leading to the enhanced performance. Combining different polymers as double sheaths as reported here might be a potential route to circumvent the dilemma of pseudo-materials, and to simultaneously improve the capacitance and stability for various energy storage devices.Pseudo-materials are effective in boosting the specific capacitance of supercapacitors, but during service their degradation may also be very strong, causing reduced cycling stability. Here, we show that a carbon nanotube sponge grafted by two conventional pseudo-polymer layers in sequence can serve as a porous supercapacitor electrode with significantly enhanced cycling stability compared with single polymer grafting. Creating conformal polymer coatings on the nanotube surface and the resulting double-sheath configuration are important structural factors leading to the enhanced performance. Combining different polymers as double sheaths as reported here might be a potential route to circumvent the dilemma of pseudo-materials, and to simultaneously improve the capacitance and stability for various energy storage devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05978j

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

    PubMed

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

    2006-10-01

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

  9. 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.

  10. Separating proteins with activated carbon.

    PubMed

    Stone, Matthew T; Kozlov, Mikhail

    2014-07-15

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

  11. 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.

  12. 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

  13. Biological activation of carbon filters.

    PubMed

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

    2006-01-01

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

  14. Carbon nanotube fiber microelectrodes show a higher resistance to dopamine fouling.

    PubMed

    Harreither, Wolfgang; Trouillon, Raphaël; Poulin, Philippe; Neri, Wilfrid; Ewing, Andrew G; Safina, Gulnara

    2013-08-06

    We have compared the properties and resistance to DA fouling of a carbon nanotube fiber (CNTF) microelectrode to a traditional carbon fiber (CF) microelectrode. These two materials show comparable electrochemical activities for outer-sphere and inner-sphere redox reactions. Although the CNTF might have a higher intrinsic RC constant, thus limiting its high-frequency behavior, the CNTF shows a significantly higher durability than the CF in terms of electrode stability. During constant oxidation of 100 μM DA, the signal measured by the CNTF microelectrode shows a 2-h window over which no decrease in current is observed. Under the same conditions, the current obtained at the CF microelectrode decreases by almost 50%. A model of the fouling process, assuming the formation of growing patches of insulator on the surface, has been compared to the data. This model is found to be in good agreement with our results and indicates a growth rate of the patches in the 0.1-2 nm s(-1) range.

  15. Your Library--Greatest Show of All! Activity Manual.

    ERIC Educational Resources Information Center

    Jackson, Mary, Ed.

    Intended as a companion volume for librarians planning a children's summer reading program, this activity manual provides ideas for games, puzzles, puppet shows, story reading, and more, all based on the theme of "Circus Summer." The manual suggests ways to promote the program, such as visits to schools, and provides directions for…

  16. 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

  17. Carbon-13 labelling shows no effect of ocean acidification on carbon transfer in Mediterranean plankton communities

    NASA Astrophysics Data System (ADS)

    Maugendre, L.; Gattuso, J.-P.; de Kluijver, A.; Soetaert, K.; van Oevelen, D.; Middelburg, J. J.; Gazeau, F.

    2017-02-01

    Despite an increasing number of experiments, no consensus has emerged on the effect of ocean acidification on plankton communities and carbon flow. During two experiments, performed in the Bay of Calvi (France, Corsica; summer 2012) and the Bay of Villefranche (France; winter 2013), nine off-shore mesocosms (∼50 m3) were deployed among which three served as controls and six were enriched with CO2 to reach partial pressure of CO2 (pCO2) levels from 450 to 1350 μatm and 350-1250 μatm in the Bay of Calvi and the Bay of Villefranche, respectively. In each mesocosm, inorganic 13C was added in order to follow carbon transfer from inorganic via bulk particulate organic carbon and phytoplankton to bacteria by means of biomarkers as well as to zooplankton and settling particles. Despite very low plankton biomasses, labelled carbon was clearly transferred through plankton communities. Incorporation rates in the various plankton compartments suggested a slow-growing community based on regenerated production in the Bay of Calvi while in the Bay of Villefranche, fast-growing species were clearly dominating community production at the start with a shift toward slow-growing species during the experiment due to nutrient limitation. Both bulk and group-specific productions rates did not respond to increasing pCO2 levels. These experiments were the first conducted in the Mediterranean Sea under low nutrient concentrations and phytoplankton biomasses and suggest that ocean acidification may not significantly impact plankton carbon flows in low nutrient low chlorophyll (LNLC) areas.

  18. 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.

  19. Croton grewioides Baill. (Euphorbiaceae) Shows Antidiarrheal Activity in Mice

    PubMed Central

    da Silva, Anne Dayse Soares; de Melo e Silva, Karoline; Neto, José Clementino; Costa, Vicente Carlos de Oliveira; Pessôa, Hilzeth de Luna F.; Tavares, Josean Fechine; da Silva, Marcelo Sobral; Cavalcante, Fabiana de Andrade

    2016-01-01

    Based on chemotaxonomy, we decided to investigate the possible antidiarrheal activity in mice of a crude ethanolic extract obtained from aerial parts of Croton grewioides (CG-EtOH). We tested for any possible toxicity in rat erythrocytes and acute toxicity in mice. Antidiarrheal activity was assessed by determining the effect of CG-EtOH on defecation frequency, liquid stool, intestinal motility and intestinal fluid accumulation. CG-EtOH showed no in vitro cytotoxicity and was not orally lethal. In contrast, the extract given intraperitoneally (at 2000 mg/kg) was lethal, but only in females. CG-EtOH produced a significant and equipotent antidiarrheal activity, both in defecation frequency (ED50 = 106.0 ± 8.1 mg/kg) and liquid stools (ED50 = 105.0 ± 9.2 mg/kg). However, CG-EtOH (125 mg/kg) decreased intestinal motility by only 22.7% ± 4.4%. Moreover, extract markedly inhibited the castor oil-induced intestinal contents (ED50 = 34.6 ± 5.4 mg/kg). We thus conclude that CG-EtOH is not orally lethal and contains active principles with antidiarrheal activity, and this effect seems to involve mostly changes in intestinal secretion. SUMMARY CG-EtOH showed no in vitro cytotoxicity and was not orally lethal. In contrast, the extract given intraperitoneally (at 2000 mg/kg) was lethal, but only in females.CG-EtOH probably contains active metabolites with antidiarrheal activity.CG-EtOH reduced the frequency and number of liquid stools.Metabolites presents in the CG-EtOH act mainly by reducing intestinal fluid and, to a lesser extent, reducing intestinal motility. Abbreviations Used: CG-EtOH: crude ethanolic extract obtained from the aerial parts of C. grewioides; WHO: World Health Organization; ED50: dose of a drug that produces 50% of its maximum effect; Emax: maximum effect PMID:27365990

  20. 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.

  1. Ovalbumin with Glycated Carboxyl Groups Shows Membrane-Damaging Activity

    PubMed Central

    Tang, Ching-Chia; Shi, Yi-Jun; Chen, Ying-Jung; Chang, Long-Sen

    2017-01-01

    The aim of the present study was to investigate whether glycated ovalbumin (OVA) showed novel activity at the lipid-water interface. Mannosylated OVA (Man-OVA) was prepared by modification of the carboxyl groups with p-aminophenyl α-dextro (d)-mannopyranoside. An increase in the number of modified carboxyl groups increased the membrane-damaging activity of Man-OVA on cell membrane-mimicking vesicles, whereas OVA did not induce membrane permeability in the tested phospholipid vesicles. The glycation of carboxyl groups caused a notable change in the gross conformation of OVA. Moreover, owing to their spatial positions, the Trp residues in Man-OVA were more exposed, unlike those in OVA. Fluorescence quenching studies suggested that the Trp residues in Man-OVA were located on the interface binds with the lipid vesicles, and their microenvironment was abundant in positively charged residues. Although OVA and Man-OVA showed a similar binding affinity for lipid vesicles, the lipid-interacting feature of Man-OVA was distinct from that of OVA. Chemical modification studies revealed that Lys and Arg residues, but not Trp residues, played a crucial role in the membrane-damaging activity of Man-OVA. Taken together, our data suggest that glycation of carboxyl groups causes changes in the structural properties and membrane-interacting features of OVA, generating OVA with membrane-perturbing activities at the lipid-water interface. PMID:28264493

  2. Tetrahdroxysqualene from Rhus taitensis Shows Antimycobacterial Activity Against Mycobacterium tuberculosis

    PubMed Central

    Noro, Jeffrey C.; Barrows, Louis R.; Gideon, Osia G.; Ireland, Chris M.; Koch, Michael; Matainaho, Teatulohi; Piskaut, Pius; Pond, Christopher D.; Bugni, Tim S.

    2010-01-01

    Tuberculosis has become a major health problem, in particular with the emergence of extremely drug resistant tuberculosis (XDRTB). In our search for new therapeutic leads against TB, we isolated a new triterpene (1) from the plant Rhus taitensis collected in Papua New Guinea. Tetrahydroxysqualene (1) was isolated using bioassay-guided fractionation of the methanolic extract of R. taitensis leaves and twigs. The structure of tetrahydroxysqualene (1) was elucidated on the basis of HRESIMS and 1D and 2D NMR spectra. Tetrahydroxysqualene (1) exhibited anti–tuberculosis activity with an MIC of 10.0 μg/mL while showing only modest cytotoxicity. PMID:18710283

  3. Extracts of marine algae show inhibitory activity against osteoclast differentiation.

    PubMed

    Koyama, Tomoyuki

    2011-01-01

    Osteoclasts are multinucleated cells that play a crucial role in bone resorption. The imbalance between bone resorption and bone formation results in osteoporosis. Therefore, substances that can suppress osteoclast formation are potential candidate materials for drug development or functional foods. There have been reports that extracts or purified compounds from marine micro- and macroalgae can suppress osteoclast differentiation. Symbioimine, isolated from the cultured dinoflagellate Symbiodinium sp., had suppressive effects against osteoclast differentiation in osteoclast-like cells. Norzoanthamine, isolated from the colonial zoanthid Zoanthas sp., has been shown to have antiosteoporosis activity in ovariectomized mice. With regard to marine extracts, the fucoxanthin-rich component from brown algae has been shown to have suppressive effects against osteoclast differentiation. An extract of Sargassum fusiforme has recently been shown to have antiosteoporosis activity. This extract suppressed both osteoclast differentiation and accelerated osteoblast formation in separate in vitro experiments. It also showed antiosteoporosis activity in ovariectomized mice by regulating the balance between bone resorption and bone formation. These marine algae and their extracts may be sources of marine medicinal foods for the prevention of osteoporosis.

  4. Plant diversity increases soil microbial activity and soil carbon storage.

    PubMed

    Lange, Markus; Eisenhauer, Nico; Sierra, Carlos A; Bessler, Holger; Engels, Christoph; Griffiths, Robert I; Mellado-Vázquez, Perla G; Malik, Ashish A; Roy, Jacques; Scheu, Stefan; Steinbeiss, Sibylle; Thomson, Bruce C; Trumbore, Susan E; Gleixner, Gerd

    2015-04-07

    Plant diversity strongly influences ecosystem functions and services, such as soil carbon storage. However, the mechanisms underlying the positive plant diversity effects on soil carbon storage are poorly understood. We explored this relationship using long-term data from a grassland biodiversity experiment (The Jena Experiment) and radiocarbon ((14)C) modelling. Here we show that higher plant diversity increases rhizosphere carbon inputs into the microbial community resulting in both increased microbial activity and carbon storage. Increases in soil carbon were related to the enhanced accumulation of recently fixed carbon in high-diversity plots, while plant diversity had less pronounced effects on the decomposition rate of existing carbon. The present study shows that elevated carbon storage at high plant diversity is a direct function of the soil microbial community, indicating that the increase in carbon storage is mainly limited by the integration of new carbon into soil and less by the decomposition of existing soil carbon.

  5. The Oral Antimalarial Drug Tafenoquine Shows Activity against Trypanosoma brucei

    PubMed Central

    Carvalho, Luis; Martínez-García, Marta; Pérez-Victoria, Ignacio; Manzano, José Ignacio; Yardley, Vanessa

    2015-01-01

    The protozoan parasite Trypanosoma brucei causes human African trypanosomiasis, or sleeping sickness, a neglected tropical disease that requires new, safer, and more effective treatments. Repurposing oral drugs could reduce both the time and cost involved in sleeping sickness drug discovery. Tafenoquine (TFQ) is an oral antimalarial drug belonging to the 8-aminoquinoline family which is currently in clinical phase III. We show here that TFQ efficiently kills different T. brucei spp. in the submicromolar concentration range. Our results suggest that TFQ accumulates into acidic compartments and induces a necrotic process involving cell membrane disintegration and loss of cytoplasmic content, leading to parasite death. Cell lysis is preceded by a wide and multitarget drug action, affecting the lysosome, mitochondria, and acidocalcisomes and inducing a depolarization of the mitochondrial membrane potential, elevation of intracellular Ca2+, and production of reactive oxygen species. This is the first report of an 8-aminoquinoline demonstrating significant in vitro activity against T. brucei. PMID:26195527

  6. A novel nucleic acid analogue shows strong angiogenic activity

    SciTech Connect

    Tsukamoto, Ikuko; Sakakibara, Norikazu; Maruyama, Tokumi; Igarashi, Junsuke; Kosaka, Hiroaki; Kubota, Yasuo; Tokuda, Masaaki; Ashino, Hiromi; Hattori, Kenichi; Tanaka, Shinji; Kawata, Mitsuhiro; Konishi, Ryoji

    2010-09-03

    Research highlights: {yields} A novel nucleic acid analogue (2Cl-C.OXT-A, m.w. 284) showed angiogenic potency. {yields} It stimulated the tube formation, proliferation and migration of HUVEC in vitro. {yields} 2Cl-C.OXT-A induced the activation of ERK1/2 and MEK in HUVEC. {yields} Angiogenic potency in vivo was confirmed in CAM assay and rabbit cornea assay. {yields} A synthesized small angiogenic agent would have great clinical therapeutic value. -- Abstract: A novel nucleic acid analogue (2Cl-C.OXT-A) significantly stimulated tube formation of human umbilical endothelial cells (HUVEC). Its maximum potency at 100 {mu}M was stronger than that of vascular endothelial growth factor (VEGF), a positive control. At this concentration, 2Cl-C.OXT-A moderately stimulated proliferation as well as migration of HUVEC. To gain mechanistic insights how 2Cl-C.OXT-A promotes angiogenic responses in HUVEC, we performed immunoblot analyses using phospho-specific antibodies as probes. 2Cl-C.OXT-A induced robust phosphorylation/activation of MAP kinase ERK1/2 and an upstream MAP kinase kinase MEK. Conversely, a MEK inhibitor PD98059 abolished ERK1/2 activation and tube formation both enhanced by 2Cl-C.OXT-A. In contrast, MAP kinase responses elicited by 2Cl-C.OXT-A were not inhibited by SU5416, a specific inhibitor of VEGF receptor tyrosine kinase. Collectively these results suggest that 2Cl-C.OXT-A-induces angiogenic responses in HUVEC mediated by a MAP kinase cascade comprising MEK and ERK1/2, but independently of VEGF receptor tyrosine kinase. In vivo assay using chicken chorioallantoic membrane (CAM) and rabbit cornea also suggested the angiogenic potency of 2Cl-C.OXT-A.

  7. Fluvoxamine, a new antidepressant drug, fails to show antiserotonin activity.

    PubMed

    Maj, J; Rogóz, Z; Skuza, G

    1982-07-09

    Fluvoxamine, (E)-5-methoxy-4'-(trifluoromethyl)valerophenone O-2(2-aminoethyl)oxime, a new antidepressant drug inhibiting serotonin (5-HT) uptake, was studied in rats and mice in order to check whether it has any central anti-5-HT activity, as do some tricyclic antidepressants, e.g. amitriptyline and doxepin. Fluvoxamine did not influence either the 5-hydroxytryptophan-induced head twitch response in mice or the tryptamine convulsions in rats. In the hind limb flexor reflex of the spinal rat the stimulation induced by fenfluramine was inhibited, that induced by LSD was not changed. Fluvoxamine also antagonized the hyperthermia (at ambient temperature of 28 degrees C), induced in rats by fenfluramine or p-chloroamphetamine. The hyperthermia caused by m-chlorophenylpiperazine was not inhibited. Fluvoxamine did not antagonize the 5-HT pressor effect in pithed rats. It has no effect on the immobility time in the behavioural despair test in rats. The results indicate that fluvoxamine fails to show anti-5-HT activity.

  8. High-Resolution Observations of a Filament showing Activated Barb

    NASA Astrophysics Data System (ADS)

    Joshi, Anand; Martin, Sara F.; Mathew, Shibu; Srivastava, Nandita

    2012-07-01

    Analysis of a filament showing an activated barb using observations from the Dutch Open Telescope (DOT) on 2010 August 20 are presented. The DOT takes Doppler images in Hα, among other wavelengths, in a region about 110 × 110 arcsec^{2} in area, at a cadence of 30~seconds. The offline image restoration technique of speckle reconstruction is applied to obtain diffraction limited images. The filament developed a new barb in 10~minutes, which disappeared within the next 35~minutes. Such a rapid formation and disappearance of a filament barb is unusual, and has not been reported earlier. Line-of-sight velocity maps were constructed from the Doppler images of the target filament. We observe flows in the filament spine towards the barb location prior to its formation, and flows in the barb towards the spine during its disappearance. Photospheric magnetograms from Heliospheric Magnetic Imager on board the Solar Dynamics Observatory, at a cadence of 45~seconds, were used to determine the changes in magnetic flux in the region surrounding the barb location. The variation of magnetic flux in this duration supports the view that barbs are rooted in minor magnetic polarity. Our analysis shows that barbs can be short-lived and formation and disappearance of the barb was associated with cancellation of magnetic flux.

  9. Silver nanoparticles synthesised using plant extracts show strong antibacterial activity.

    PubMed

    Kumari, Avnesh; Guliani, Anika; Singla, Rubbel; Yadav, Ramdhan; Yadav, Sudesh Kumar

    2015-06-01

    In this study, three plants Populus alba, Hibiscus arboreus and Lantana camara were explored for the synthesis of silver nanoparticles (SNPs). The effect of reaction temperature and leaf extract (LE) concentration of P. alba, H. arboreus and L. camara was evaluated on the synthesis and size of SNPs. The SNPs were characterised by ultra-violet-visible spectroscopy, scanning electron microscopy and atomic force microscopy. The synthesis rate of SNPs was highest with LE of L. camara followed by H. arboreus and P. alba under similar conditions. L. camara LE showed maximum potential of smaller size SNPs synthesis, whereas bigger particles were formed by H. arboreous LE. The size and shape of L. camara LE synthesised SNPs were analysed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). TEM analysis revealed the formation of SNPs of average size 17±9.5 nm with 5% LE of L. camara. The SNPs synthesised by LE of L. camara showed strong antibacterial activity against Escherichia coli. The results document that desired size SNPs can be synthesised using these plant LEs at a particular temperature for applications in the biomedical field.

  10. 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.

  11. 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.

  12. Enhanced capacitive properties of commercial activated carbon by re-activation in molten carbonates

    NASA Astrophysics Data System (ADS)

    Lu, Beihu; Xiao, Zuoan; Zhu, Hua; Xiao, Wei; Wu, Wenlong; Wang, Dihua

    2015-12-01

    Simple, affordable and green methods to improve capacitive properties of commercial activated carbon (AC) are intriguing since ACs possess a predominant role in the commercial supercapacitor market. Herein, we report a green reactivation of commercial ACs by soaking ACs in molten Na2CO3-K2CO3 (equal in mass ratios) at 850 °C combining the merits of both physical and chemical activation strategies. The mechanism of molten carbonate treatment and structure-capacitive activity correlations of the ACs are rationalized. Characterizations show that the molten carbonate treatment increases the electrical conductivity of AC without compromising its porosity and wettability of electrolytes. Electrochemical tests show the treated AC exhibited higher specific capacitance, enhanced high-rate capability and excellent cycle performance, promising its practical application in supercapacitors. The present study confirms that the molten carbonate reactivation is a green and effective method to enhance capacitive properties of ACs.

  13. 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.

  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. Modified Activated Carbon Perchlorate Sorbents

    DTIC Science & Technology

    2007-01-25

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

  16. Superhydrophobic activated carbon-coated sponges for separation and absorption.

    PubMed

    Sun, Hanxue; Li, An; Zhu, Zhaoqi; Liang, Weidong; Zhao, Xinhong; La, Peiqing; Deng, Weiqiao

    2013-06-01

    Highly porous activated carbon with a large surface area and pore volume was synthesized by KOH activation using commercially available activated carbon as a precursor. By modification with polydimethylsiloxane (PDMS), highly porous activated carbon showed superhydrophobicity with a water contact angle of 163.6°. The changes in wettability of PDMS- treated highly porous activated carbon were attributed to the deposition of a low-surface-energy silicon coating onto activated carbon (confirmed by X-ray photoelectron spectroscopy), which had microporous characteristics (confirmed by XRD, SEM, and TEM analyses). Using an easy dip-coating method, superhydrophobic activated carbon-coated sponges were also fabricated; those exhibited excellent absorption selectivity for the removal of a wide range of organics and oils from water, and also recyclability, thus showing great potential as efficient absorbents for the large-scale removal of organic contaminants or oil spills from water.

  17. NASA's Fermi Shows How Active Galaxies Can Be

    NASA Video Gallery

    Active galaxies called blazars make up the largest class of objects detected by Fermi's Large Area Telescope (LAT). Massive black holes in the hearts of these galaxies fire particle jets in our dir...

  18. 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.

  19. 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.

  20. Psychopaths Show Enhanced Amygdala Activation during Fear Conditioning.

    PubMed

    Schultz, Douglas H; Balderston, Nicholas L; Baskin-Sommers, Arielle R; Larson, Christine L; Helmstetter, Fred J

    2016-01-01

    Psychopathy is a personality disorder characterized by emotional deficits and a failure to inhibit impulsive behavior and is often subdivided into "primary" and "secondary" psychopathic subtypes. The maladaptive behavior related to primary psychopathy is thought to reflect constitutional "fearlessness," while the problematic behavior related to secondary psychopathy is motivated by other factors. The fearlessness observed in psychopathy has often been interpreted as reflecting a fundamental deficit in amygdala function, and previous studies have provided support for a low-fear model of psychopathy. However, many of these studies fail to use appropriate screening procedures, use liberal inclusion criteria, or have used unconventional approaches to assay amygdala function. We measured brain activity with BOLD imaging in primary and secondary psychopaths and non-psychopathic control subjects during Pavlovian fear conditioning. In contrast to the low-fear model, we observed normal fear expression in primary psychopaths. Psychopaths also displayed greater differential BOLD activity in the amygdala relative to matched controls. Inverse patterns of activity were observed in the anterior cingulate cortex (ACC) for primary versus secondary psychopaths. Primary psychopaths exhibited a pattern of activity in the dorsal and ventral ACC consistent with enhanced fear expression, while secondary psychopaths exhibited a pattern of activity in these regions consistent with fear inhibition. These results contradict the low-fear model of psychopathy and suggest that the low fear observed for psychopaths in previous studies may be specific to secondary psychopaths.

  1. Psychopaths Show Enhanced Amygdala Activation during Fear Conditioning

    PubMed Central

    Schultz, Douglas H.; Balderston, Nicholas L.; Baskin-Sommers, Arielle R.; Larson, Christine L.; Helmstetter, Fred J.

    2016-01-01

    Psychopathy is a personality disorder characterized by emotional deficits and a failure to inhibit impulsive behavior and is often subdivided into “primary” and “secondary” psychopathic subtypes. The maladaptive behavior related to primary psychopathy is thought to reflect constitutional “fearlessness,” while the problematic behavior related to secondary psychopathy is motivated by other factors. The fearlessness observed in psychopathy has often been interpreted as reflecting a fundamental deficit in amygdala function, and previous studies have provided support for a low-fear model of psychopathy. However, many of these studies fail to use appropriate screening procedures, use liberal inclusion criteria, or have used unconventional approaches to assay amygdala function. We measured brain activity with BOLD imaging in primary and secondary psychopaths and non-psychopathic control subjects during Pavlovian fear conditioning. In contrast to the low-fear model, we observed normal fear expression in primary psychopaths. Psychopaths also displayed greater differential BOLD activity in the amygdala relative to matched controls. Inverse patterns of activity were observed in the anterior cingulate cortex (ACC) for primary versus secondary psychopaths. Primary psychopaths exhibited a pattern of activity in the dorsal and ventral ACC consistent with enhanced fear expression, while secondary psychopaths exhibited a pattern of activity in these regions consistent with fear inhibition. These results contradict the low-fear model of psychopathy and suggest that the low fear observed for psychopaths in previous studies may be specific to secondary psychopaths. PMID:27014154

  2. Show and Tell: An Appreciation of "Making" Activities.

    ERIC Educational Resources Information Center

    Kozolanka, Karne

    This paper describes the incorporation of a "making" activity as part of a course for education majors at Queen's Faculty of Education of the University of Regina (Saskatchewan, Canada). The course was an introductory one in which students explored the methods and merits of outdoor and experiential education. Each student was given a…

  3. Enhanced adsorption of humic acids on ordered mesoporous carbon compared with microporous activated carbon.

    PubMed

    Liu, Fengling; Xu, Zhaoyi; Wan, Haiqin; Wan, Yuqiu; Zheng, Shourong; Zhu, Dongqiang

    2011-04-01

    Humic acids are ubiquitous in surface and underground waters and may pose potential risk to human health when present in drinking water sources. In this study, ordered mesoporous carbon was synthesized by means of a hard template method and further characterized by X-ray diffraction, N2 adsorption, transition electron microscopy, elemental analysis, and zeta-potential measurement. Batch experiments were conducted to evaluate adsorption of two humic acids from coal and soil, respectively, on the synthesized carbon. For comparison, a commercial microporous activated carbon and nonporous graphite were included as additional adsorbents; moreover, phenol was adopted as a small probe adsorbate. Pore size distribution characterization showed that the synthesized carbon had ordered mesoporous structure, whereas the activated carbon was composed mainly of micropores with a much broader pore size distribution. Accordingly, adsorption of the two humic acids was substantially lower on the activated carbon than on the synthesized carbon, because of the size-exclusion effect. In contrast, the synthesized carbon and activated carbon showed comparable adsorption for phenol when the size-exclusion effect was not in operation. Additionally, we verified by size-exclusion chromatography studies that the synthesized carbon exhibited greater adsorption for the large humic acid fraction than the activated carbon. The pH dependence of adsorption on the three carbonaceous adsorbents was also compared between the two test humic acids. The findings highlight the potential of using ordered mesoporous carbon as a superior adsorbent for the removal of humic acids.

  4. Conjugation of ovotransferrin with catechin shows improved antioxidant activity.

    PubMed

    You, Juan; Luo, Yongkang; Wu, Jianping

    2014-03-26

    Ovotransferrin (OTF), representing 12-13% of the total egg white, is a member of transferrin family with antimicrobial and antioxidant activities. Catechin is a polyphenolic antioxidant found in green tea. The objective of the study was to conjugate ovotransferrin with catechin to improve the antioxidant activity of OTF. Conjugates were prepared either by the free radical method using hydrogen peroxide-ascorbic acid as the initiator or by the alkaline method at pH of 9.0. The oxygen-radical-scavenging effect was increased from 3.95 mol trolox equivalent (TE)/mol of ovotransferrin to 22.80 and 17.14 mol TE/mol sample, respectively, in radical and alkaline prepared conjugates, which indicated that conjugation with catechin is an effective way to improve antioxidant activity of the protein. Conjugation between ovotransferrin and catechin was analyzed by fluorescence analyses, ultra performance liquid chromatography, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and liquid chromatography coupled online to a tandem mass spectrometer. Catechin was covalently bound to lysine (residues 327) and glutamic acid (residues 186) in ovotransferrin. The ovotransferrin-catechin conjugate may have a potential application as a functional food and nutraceutical ingredient.

  5. 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

  6. Insurance Applications of Active Fault Maps Showing Epistemic Uncertainty

    NASA Astrophysics Data System (ADS)

    Woo, G.

    2005-12-01

    Insurance loss modeling for earthquakes utilizes available maps of active faulting produced by geoscientists. All such maps are subject to uncertainty, arising from lack of knowledge of fault geometry and rupture history. Field work to undertake geological fault investigations drains human and monetary resources, and this inevitably limits the resolution of fault parameters. Some areas are more accessible than others; some may be of greater social or economic importance than others; some areas may be investigated more rapidly or diligently than others; or funding restrictions may have curtailed the extent of the fault mapping program. In contrast with the aleatory uncertainty associated with the inherent variability in the dynamics of earthquake fault rupture, uncertainty associated with lack of knowledge of fault geometry and rupture history is epistemic. The extent of this epistemic uncertainty may vary substantially from one regional or national fault map to another. However aware the local cartographer may be, this uncertainty is generally not conveyed in detail to the international map user. For example, an area may be left blank for a variety of reasons, ranging from lack of sufficient investigation of a fault to lack of convincing evidence of activity. Epistemic uncertainty in fault parameters is of concern in any probabilistic assessment of seismic hazard, not least in insurance earthquake risk applications. A logic-tree framework is appropriate for incorporating epistemic uncertainty. Some insurance contracts cover specific high-value properties or transport infrastructure, and therefore are extremely sensitive to the geometry of active faulting. Alternative Risk Transfer (ART) to the capital markets may also be considered. In order for such insurance or ART contracts to be properly priced, uncertainty should be taken into account. Accordingly, an estimate is needed for the likelihood of surface rupture capable of causing severe damage. Especially where a

  7. Trajectory Hunting: Analysis of UARS Measurements showing Rapid Chlorine Activation

    NASA Technical Reports Server (NTRS)

    Danilin, M.Y.; Santee, M. L.; Rodriquez, J. M.; Ko, M. K. W.; Mergenthaler, J. M.; Kumer, J. B.; Tabazadeh, A.

    1998-01-01

    Trajectory hunting (i.e., a technique to find air parcels sampled at least twice over the course of a few days) is applied to analyze Upper Atmosphere Research Satellite (UARS) measurements in conjunction with the AER photochemical box model. In this study, we investigate rapid chlorine activation in the Arctic lower stratosphere on 29 Dec 1992 associated with a polar stratospheric cloud (PSC) event. Six air parcels that have been sampled twice were followed along 5-day trajectories at the 465 K (approximately 46 mb) and 585 K (approximately 22 mb) levels. A detailed sensitivity study with the AER. photochemical box model along these trajectories leads to the following conclusions for the episode considered: (1) model results are in better agreement with UARS measurements at these levels if the UKMO temperature is decreased by at least 1-2 K; (2) the NAT (nitric acid trihydrate) PSC formation scheme produces results in better agreement with observations than the STS (supercooled ternary solution) scheme; (3) the model can explain the UARS measurements at 585 K, but under-estimates the ClO abundance at 465 K, suggesting some inconsistency between the UARS measurements at this level.

  8. Trajectory Hunting: Analysis of UARS Measurements Showing Rapid Chlorine Activation

    NASA Technical Reports Server (NTRS)

    Danilin, M. Y.; Santee, M. L.; Rodriquez, J. M.; Ko, M. K. W.; Mergenthaler, J. M.; Kumer, J. B.; Tabazadeh, A.

    1998-01-01

    Trajectory hunting (i.e., a technique to find air parcels sampled at least twice over the course of a few days) is applied to analyze Upper Atmosphere Research Satellite (UARS) measurements in conjunction with the AER photochemical box model. In this study, we investigate rapid chlorine activation in the Arctic lower stratosphere on 29 Dec. 1992 associated with a polar stratospheric cloud (PSC) event. Six air parcels that have been sampled twice were followed along 5-day trajectories at the 465 K (approx. 46 mb) and 585 K (approxi. 22 mb) levels. A detailed sensitivity study with the AER photochemical box model along these trajectories leads to the following conclusions for the episode considered: 1) model results are in better agreement with UARS measurements at these levels if the U.K. Meteorological Office (UKMO) temperature is decreased by at least 1-2 K; 2) the NAT (nitric acid trihydrate) PSC formation scheme produces results in better agreement with observations than the STS (supercooled ternary solution) scheme; 3) the model can explain the UARS measurements at 585 K, but under-estimates the ClO abundance at 465 K, suggesting some inconsistency between the UARS measurements at this level.

  9. Characterization of Activated Carbons from Oil-Palm Shell by CO2 Activation with No Holding Carbonization Temperature

    PubMed Central

    Herawan, S. G.; Hadi, M. S.; Ayob, Md. R.; Putra, A.

    2013-01-01

    Activated carbons can be produced from different precursors, including coals of different ranks, and lignocellulosic materials, by physical or chemical activation processes. The objective of this paper is to characterize oil-palm shells, as a biomass byproduct from palm-oil mills which were converted into activated carbons by nitrogen pyrolysis followed by CO2 activation. The effects of no holding peak pyrolysis temperature on the physical characteristics of the activated carbons are studied. The BET surface area of the activated carbon is investigated using N2 adsorption at 77 K with selected temperatures of 500, 600, and 700°C. These pyrolysis conditions for preparing the activated carbons are found to yield higher BET surface area at a pyrolysis temperature of 700°C compared to selected commercial activated carbon. The activated carbons thus result in well-developed porosities and predominantly microporosities. By using this activation method, significant improvement can be obtained in the surface characteristics of the activated carbons. Thus this study shows that the preparation time can be shortened while better results of activated carbon can be produced. PMID:23737721

  10. 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.

  11. Sulfur dioxide - Episodic injection shows evidence for active Venus volcanism

    NASA Astrophysics Data System (ADS)

    Esposito, L. W.

    1984-03-01

    Pioneer Venus ultraviolet spectra from the first 5 years of operation show a decline (by more than a factor of 10) in sulfur dioxide abundance at the cloud tops and in the amount of submicron haze above the clouds. At the time of the Pioneer Venus encounter, the values for both parameters greatly exceeded earlier upper limits. However, Venus had a similar appearance in the late 1950's, implying the episodic injection of sulfur dioxide possibly caused by episodic volcanism. The amount of haze in the Venus middle atmosphere is about ten times that found in earth's stratosphere after the most recent major volcanic eruptions, and the thermal energy required for this injection on Venus is greater by about an order of magnitude than the largest of these recent earth eruptions and about as large as the Krakatoa eruption of 1883. The episodic behavior of sulfur dioxide implies that steady-state models of the chemistry and dynamics of cloud-top regions may be of limited use.

  12. Sulfur dioxide - Episodic injection shows evidence for active Venus volcanism

    NASA Technical Reports Server (NTRS)

    Esposito, L. W.

    1984-01-01

    Pioneer Venus ultraviolet spectra from the first 5 years of operation show a decline (by more than a factor of 10) in sulfur dioxide abundance at the cloud tops and in the amount of submicron haze above the clouds. At the time of the Pioneer Venus encounter, the values for both parameters greatly exceeded earlier upper limits. However, Venus had a similar appearance in the late 1950's, implying the episodic injection of sulfur dioxide possibly caused by episodic volcanism. The amount of haze in the Venus middle atmosphere is about ten times that found in earth's stratosphere after the most recent major volcanic eruptions, and the thermal energy required for this injection on Venus is greater by about an order of magnitude than the largest of these recent earth eruptions and about as large as the Krakatoa eruption of 1883. The episodic behavior of sulfur dioxide implies that steady-state models of the chemistry and dynamics of cloud-top regions may be of limited use.

  13. Carbon nanomaterials: Biologically active fullerene derivatives.

    PubMed

    Bogdanović, Gordana; Djordjević, Aleksandar

    2016-01-01

    Since their discovery, fullerenes, carbon nanotubes, and graphene attract significant attention of researches in various scientific fields including biomedicine. Nano-scale size and a possibility for diverse surface modifications allow carbon nanoallotropes to become an indispensable nanostructured material in nanotechnologies, including nanomedicine. Manipulation of surface chemistry has created diverse populations of water-soluble derivatives of fullerenes, which exhibit different behaviors. Both non-derivatized and derivatized fullerenes show various biological activities. Cellular processes that underline their toxicity are oxidative, genotoxic, and cytotoxic responses.The antioxidant/cytoprotective properties of fullerenes and derivatives have been considered in the prevention of organ oxidative damage and treatment. The same unique physiochemical properties of nanomaterials may also be associated with potential health hazards. Non-biodegradability and toxicity of carbon nanoparticles still remain a great concern in the area of biomedical application. In this review, we report on basic physical and chemical properties of carbon nano-clusters--fullerenes, nanotubes, and grapheme--their specificities, activities, and potential application in biological systems. Special emphasis is given to our most important results obtained in vitro and in vivo using polyhydroxylated fullerene derivative C₆₀(OH)₂₄.

  14. [Effects of different fertilizer application on soil active organic carbon].

    PubMed

    Zhang, Rui; Zhang, Gui-Long; Ji, Yan-Yan; Li, Gang; Chang, Hong; Yang, Dian-Lin

    2013-01-01

    The variation characteristics of the content and components of soil active organic carbon under different fertilizer application were investigated in samples of calcareous fluvo-aquic soil from a field experiment growing winter wheat and summer maize in rotation in the North China Plain. The results showed that RF (recommended fertilization), CF (conventional fertilization) and NPK (mineral fertilizer alone) significantly increased the content of soil dissolved organic carbon and easily oxidized organic carbon by 24.92-38.63 mg x kg(-1) and 0.94-0.58 mg x kg(-1) respectively compared to CK (unfertilized control). The soil dissolved organic carbon content under OM (organic manure) increased greater than those under NPK and single fertilization, soil easily oxidized organic carbon content under OM and NPK increased greater than that under single chemical fertilization. OM and NPK showed no significant role in promoting the soil microbial biomass carbon, but combined application of OM and NPK significantly increased the soil microbial biomass carbon content by 36.06% and 20.69%, respectively. Soil easily oxidized organic carbon, dissolved organic carbon and microbial biomass carbon accounted for 8.41% - 14.83%, 0.47% - 0.70% and 0.89% - 1.20% of the total organic carbon (TOC), respectively. According to the results, the fertilizer application significantly increased the proportion of soil dissolved organic carbon and easily oxidized organic carbon, but there was no significant difference in the increasing extent of dissolved organic carbon. The RF and CF increased the proportion of soil easily oxidized organic carbon greater than OM or NPK, and significantly increased the proportion of microbial biomass carbon. OM or RF had no significant effect on the proportion of microbial biomass carbon. Therefore, in the field experiment, appropriate application of organic manure and chemical fertilizers played an important role for the increase of soil active organic carbon

  15. Activated Carbon Modified with Copper for Adsorption of Propanethiol

    PubMed Central

    Moreno-Piraján, Juan Carlos; Tirano, Joaquín; Salamanca, Brisa; Giraldo, Liliana

    2010-01-01

    Activated carbons were characterized texturally and chemically before and after treatment, using surface area determination in the BET model, Boehm titration, TPR, DRX and immersion calorimetry. The adsorption capacity and the kinetics of sulphur compound removal were determined by gas chromatography. It was established that the propanethiol retention capacity is dependent on the number of oxygenated groups generated on the activated carbon surface and that activated carbon modified with CuO at 0.25 M shows the highest retention of propanethiol. Additionally is proposed a mechanism of decomposition of propenothiol with carbon-copper system. PMID:20479992

  16. Technique for surface oxidation of activated carbon

    SciTech Connect

    Sircar, S.; Golden, T.C.

    1987-10-27

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

  17. Adsorption of carbon monoxide on activated carbon tin ligand

    NASA Astrophysics Data System (ADS)

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

    2000-09-01

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

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

    NASA Astrophysics Data System (ADS)

    Uçar, Suat; Erdem, Murat; Tay, Turgay; Karagöz, 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.

  19. Adsorption of EDTA on activated carbon from aqueous solutions.

    PubMed

    Zhu, Hai-song; Yang, Xiao-juan; Mao, Yan-peng; Chen, Yu; Long, Xiang-li; Yuan, Wei-kang

    2011-01-30

    In this study, the adsorption of EDTA on activated carbon from aqueous solutions has been investigated in a batch stirred cell. Experiments have been carried out to investigate the effects of temperature, EDTA concentration, pH, activated carbon mass and particle size on EDTA adsorption. The experimental results manifest that the EDTA adsorption rate increases with its concentration in the aqueous solutions. EDTA adsorption also increases with temperature. The EDTA removal from the solution increases as activated carbon mass increases. The Langmuir and Freundlich equilibrium isotherm models are found to provide a good fitting of the adsorption data, with R(2) = 0.9920 and 0.9982, respectively. The kinetic study shows that EDTA adsorption on the activated carbon is in good compliance with the pseudo-second-order kinetic model. The thermodynamic parameters (E(a), ΔG(0), ΔH(0), ΔS(0)) obtained indicate the endothermic nature of EDTA adsorption on activated carbon.

  20. Sorption of boron trifluoride by activated carbons

    SciTech Connect

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

    1988-01-10

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

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

    PubMed

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

    2016-11-24

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

  2. 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

  3. Nickel adsorption by sodium polyacrylate-grafted activated carbon.

    PubMed

    Ewecharoen, A; Thiravetyan, P; Wendel, E; Bertagnolli, H

    2009-11-15

    A novel sodium polyacrylate grafted activated carbon was produced by using gamma radiation to increase the number of functional groups on the surface. After irradiation the capacity for nickel adsorption was studied and found to have increased from 44.1 to 55.7 mg g(-1). X-ray absorption spectroscopy showed that the adsorbed nickel on activated carbon and irradiation-grafted activated carbon was coordinated with 6 oxygen atoms at 2.04-2.06 A. It is proposed that this grafting technique could be applied to other adsorbents to increase the efficiency of metal adsorption.

  4. Production and characterization of lignocellulosic biomass-derived activated carbon.

    PubMed

    Namazi, A B; Jia, C Q; Allen, D G

    2010-01-01

    The goal of this work is to establish the technical feasibility of producing activated carbon from pulp mill sludges. KOH chemical activation of four lignocellulosic biomass materials, two sludges from pulp mills, one sludge for a linerboard mill, and cow manure, were investigated experimentally, with a focus on the effects of KOH/biomass ratio (1/1, 1.5/1 and 2/1), activation temperature (400-600 °C) and activation time (1 to 2 h) on the development of porosity. The activation products were characterized for their physical and chemical properties using a surface area analyzer, scanning electron microscopy and Fourier transform infrared spectroscopy. Experiments were carried out to establish the effectiveness of the lignocellulosic biomass-derived activated carbon in removing methylene blue (MB), a surrogate of large organic molecules. The results show that the activated carbon are highly porous with specific surface area greater than 500 m²/g. The yield of activated carbon was greater than the percent of fixed carbon in the dry sludge, suggesting that the activation process was able to capture a substantial amount of carbon from the organic matter in the sludge. While 400 °C was too low, 600 °C was high enough to sustain a substantial rate of activation for linerboard sludge. The KOH/biomass ratio, activation temperature and time all play important roles in pore development and yield control, allowing optimization of the activation process. MB adsorption followed a Langmuir isotherm for all four activated carbon, although the adsorption capacity of NK-primary sludge-derived activated carbon was considerably lower than the rest, consistent with its lower specific surface area.

  5. Geologic map showing springs rich in carbon dioxide or or chloride in California

    USGS Publications Warehouse

    Barnes, Ivan; Irwin, William P.; Gibson, H.A.

    1975-01-01

    Carbon dioxide- and chloride-rich springs occur in all geologic provinces in California, but are most abundant in the Coast Ranges and the Great Valley. The carbon-dioxide-rich springs issue mainly from Franciscan terrane; they also are rich in boron and are of the metamorphic type (White, 1957). Based on isotopic data, either the carbon dioxide or the water, or both, may be of metamorphic origin. Because of high magnesium values, the water of many of the carbon-dioxide-rich springs is thought to have passed through serpentinite. The chloride-rich waters are most common in rocks of the Great Valley sequence. Nearly all are more dilute than present-day sea water. The similarity in isotopic compositions of the metamorphic carbon-dioxide-rich water and the chloride-rich water may indicate a similar extent of water-rock interaction.

  6. The transport properties of activated carbon fibers

    SciTech Connect

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

    1990-07-01

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

  7. Solvent recovery improved with activated carbon fibers

    SciTech Connect

    Not Available

    1982-11-01

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

  8. 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.

  9. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    NASA Astrophysics Data System (ADS)

    Byamba-Ochir, Narandalai; Shim, Wang Geun; Balathanigaimani, M. S.; Moon, Hee

    2016-08-01

    Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816-2063 m2/g and of 0.55-1.61 cm3/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  10. Chemical activation of carbon mesophase pitches.

    PubMed

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

    2006-06-01

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

  11. 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.

  12. 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.

  13. Effects of CO 2 activation on porous structures of coconut shell-based activated carbons

    NASA Astrophysics Data System (ADS)

    Guo, Shenghui; Peng, Jinhui; Li, Wei; Yang, Kunbin; Zhang, Libo; Zhang, Shimin; Xia, Hongying

    2009-07-01

    In this paper, textural characterization of an activated carbon derived from carbonized coconut shell char obtained at carbonization temperature of 600 °C for 2 h by CO 2 activation was investigated. The effects of activation temperature, activation time and flow rate of CO 2 on the BET surface area, total volume, micropore volume and yield of activated carbons prepared were evaluated systematically. The results showed that: (i) enhancing activation temperature was favorable to the formation of pores, widening of pores and an increase in mesopores; (ii) increasing activation time was favorable to the formation of micropores and mesopores, and longer activation time would result in collapsing of pores; (iii) increasing flow rate of CO 2 was favorable to the reactions of all active sites and formation of pores, further increasing flow rate of CO 2 would lead carbon to burn out and was unfavorable to the formation of pores. The degree of surface roughness of activated carbon prepared was measured by the fractal dimension which was calculated by FHH (Frenkel-Halsey-Hill) theory. The fractal dimensions of activated carbons prepared were greater than 2.6, indicating the activated carbon samples prepared had very irregular structures, and agreed well with those of average micropore size.

  14. Monitoring by Control Technique - Activated Carbon Adsorber

    EPA Pesticide Factsheets

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

  15. Sink effect in activated carbon-supported hydrodesulfurization catalysts

    SciTech Connect

    Laine, J.; Labady, M.; Severino, F.; Yunes, S.

    1997-03-01

    A synergistic effect has been proposed in previous papers, attempting to explain the higher activity of activated carbon-supported hydrodesulfurization (HDS) catalysts with respect to conventional alumina-supported catalysts, reported earlier. However, activated carbon characteristics can be strongly affected by the raw material and the method of activation. Thus, previous work using Ni-Mo catalysts supported on two different activated carbons (one prepared by {open_quotes}physical{close_quotes} and the other by {open_quotes}chemical{close_quotes} activation) showed different optimal Ni concentrations for higher HDS activity, such difference being attributed to the predominance of Topsoe`s Type I {open_quotes}NiMoS{close_quotes} phase in one carbon and the predominance of Type II in the other. Due to the lack of proper characterization of the activated carbon supported catalysts of the previous work, this paper presents further data suggesting that microporosity provided by the activated carbon may be the responsible for the above referred synergism. 12 refs., 1 fig., 3 tabs.

  16. Satellite microglia show spontaneous electrical activity that is uncorrelated with activity of the attached neuron.

    PubMed

    Wogram, Emile; Wendt, Stefan; Matyash, Marina; Pivneva, Tatyana; Draguhn, Andreas; Kettenmann, Helmut

    2016-06-01

    Microglia are innate immune cells of the brain. We have studied a subpopulation of microglia, called satellite microglia. This cell type is defined by a close morphological soma-to-soma association with a neuron, indicative of a direct functional interaction. Indeed, ultrastructural analysis revealed closely attached plasma membranes of satellite microglia and neurons. However, we found no apparent morphological specializations of the contact, and biocytin injection into satellite microglia showed no dye-coupling with the apposed neurons or any other cell. Likewise, evoked local field potentials or action potentials and postsynaptic potentials of the associated neuron did not lead to any transmembrane currents or non-capacitive changes in the membrane potential of the satellite microglia in the cortex and hippocampus. Both satellite and non-satellite microglia, however, showed spontaneous transient membrane depolarizations that were not correlated with neuronal activity. These events could be divided into fast-rising and slow-rising depolarizations, which showed different characteristics in satellite and non-satellite microglia. Fast-rising and slow-rising potentials differed with regard to voltage dependence. The frequency of these events was not affected by the application of tetrodotoxin, but the fast-rising event frequency decreased after application of GABA. We conclude that microglia show spontaneous electrical activity that is uncorrelated with the activity of adjacent neurons.

  17. An active principle of Nigella sativa L., thymoquinone, showing significant antimicrobial activity against anaerobic bacteria

    PubMed Central

    Randhawa, Mohammad Akram; Alenazy, Awwad Khalaf; Alrowaili, Majed Gorayan; Basha, Jamith

    2017-01-01

    Aim/Background: Thymoquinone (TQ) is the major active principle of Nigella sativa seed (black seed) and is known to control many fungi, bacteria, and some viruses. However, the activity of TQ against anaerobic bacteria is not well demonstrated. Anaerobic bacteria can cause severe infections, including diarrhea, aspiration pneumonia, and brain abscess, particularly in immunodeficient individuals. The present study aimed to investigate the in vitro antimicrobial activity of TQ against some anaerobic pathogens in comparison to metronidazole. Methods: Standard, ATCC, strains of four anaerobic bacteria (Clostridium difficile, Clostridium perfringens, Bacteroides fragilis, and Bacteroides thetaiotaomicron), were initially isolated on special Brucella agar base (with hemin and vitamin K). Then, minimum inhibitory concentrations (MICs) of TQ and metronidazole were determined against these anaerobes when grown in Brucella agar, using serial agar dilution method according to the recommended guidelines for anaerobic organisms instructed by the Clinical and Laboratory Standards Institute. Results: TQ showed a significant antimicrobial activity against anaerobic bacteria although much weaker than metronidazole. MICs of TQ and metronidazole against various anaerobic human pathogens tested were found to be between 10-160 mg/L and 0.19-6.25 mg/L, respectively. Conclusions: TQ controlled the anaerobic human pathogenic bacteria, which supports the use of N. sativa in the treatment of diarrhea in folk medicine. Further investigations are in need for determination of the synergistic effect of TQ in combination with metronidazole and the activity of derivatives of TQ against anaerobic infections. PMID:28163966

  18. Waste polyvinylchloride derived pitch as a precursor to develop carbon fibers and activated carbon fibers.

    PubMed

    Qiao, W M; Yoon, S H; Mochida, I; Yang, J H

    2007-01-01

    Polyvinylchloride (PVC) was successfully recycled through the solvent extraction from waste pipe with an extraction yield of ca. 86%. The extracted PVC was pyrolyzed by a two-stage process (260 and 410 degrees C) to obtain free-chlorine PVC based pitch through an effective removal of chlorine from PVC during the heat-treatment. As-prepared pitch (softening point: 220 degrees C) was spun, stabilized, carbonized into carbon fibers (CFs), and further activated into activated carbon fibers (ACFs) in a flow of CO2. As-prepared CFs show comparable mechanical properties to commercial CFs, whose maximum tensile strength and modulus are 862 MPa and 62 GPa, respectively. The resultant ACFs exhibit a high surface area of 1200 m2/g, narrow pore size distribution and a low oxygen content of 3%. The study provides an effective insight to recycle PVC from waste PVC and develop a carbon precursor for high performance carbon materials such as CFs and ACFs.

  19. 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

  20. Peracetylated sugar derivatives show high solubility in liquid and supercritical carbon dioxide.

    PubMed

    Potluri, Vijay K; Xu, Jianhang; Enick, Robert; Beckman, Eric; Hamilton, Andrew D

    2002-07-11

    [structure: see text] Acetylated sugars derivatives exhibit high solubility in liquid and supercritical carbon dioxide (scCO(2)). Peracetylated sorbitol and beta-D-galactose are soluble under mild conditions in scCO(2), high pressures are required to dissolve peracetylated beta-cyclodextrin, and peracetoxyalkyl chains impart CO(2)-solubility to amides.

  1. Recent Data Analysis of Carbon ACtivation

    NASA Astrophysics Data System (ADS)

    Jiang, Hui Ming; Smith, Elizabeth; Padalino, Stephen; Baumgart, Leigh; Suny Geneseooltz, Katie; Colburn, Robyn; Fuschino, Julia

    2002-10-01

    A method for measuring tertiary neutrons produced in Inertial Confinement Fusion reactions has been developed using carbon activation. Ultra pure samples of carbon, free from positron-emitting contaminants must be used in the detection. Our primary goal has been to reduce the contamination level by refining purification and packaging procedures. This process involves baking the disks in a vacuum oven to 1000¢XC @ 200 microns for a prescribed bake time without exposing the disks to nitrogen in the air which is a major contaminant. Recent experiments were conducted to determine the optimal bake time for purification. Disks were baked for varying times, from one hour to five hours, and then exposed to high-neutron-yield ( 5 x 1013) shots on OMEGA. Data collected was normalized to the same time interval and the same primary neutron yield, and no significant difference in the number of background counts was seen. Experimental results also indicated that disks that were exposed to air for short time intervals showed a significant increase in the number of contamination counts. This further supports our findings that the gaseous diffusion through graphite disks is very high. Experimental results of these findings will be presented. Research funded in part by the United States Department of Energy.

  2. 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.

  3. 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...

  4. 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.

  5. Preparation and characterization of activated carbon from marine macro-algal biomass.

    PubMed

    Aravindhan, R; Raghava Rao, J; Unni Nair, B

    2009-03-15

    Activated carbons prepared from two macro-algal biomass Sargassum longifolium (SL) and Hypnea valentiae (HV) have been examined for the removal of phenol from aqueous solution. The activated carbon has been prepared by zinc chloride activation. Experiments have been carried out at different activating agent/precursor ratio and carbonization temperature, which had significant effect on the pore structure of carbon. Developed activated carbon has been characterized by BET surface area (S(BET)) analysis and iodine number. The carbons, ZSLC-800 and ZHVC-800, showed surface area around 802 and 783 m(2)g(-1), respectively. The activated carbon developed showed substantial capability to adsorb phenol from aqueous solutions. The kinetic data were fitted to the models of pseudo-first-order, pseudo-second-order and intraparticle diffusion models. Column studies have also been carried out with ZSLC-800 activated carbon.

  6. Carbon-sulfur plots to show diagenetic and epigenetic sulfidation in sediments

    NASA Astrophysics Data System (ADS)

    Leventhal, Joel S.

    1995-03-01

    Organic carbon vs. sulfide sulfur plots are now being used regularly by many geochemists to help understand recent and ancient depositional environments and diagenetic processes. Usually, these plots are useful to recognize nonmarine vs. marine environments or oxic vs. anoxic vs. euxinic depositional environments. However, C vs. S plots can also indicate diagenetic and epigenetic events that produce “excess” sulfide. Four new examples are presented and discussed.

  7. Activated Carbon Textile via Chemistry of Metal Extraction for Supercapacitors.

    PubMed

    Lam, Do Van; Jo, Kyungmin; Kim, Chang-Hyun; Kim, Jae-Hyun; Lee, Hak-Joo; Lee, Seung-Mo

    2016-12-27

    Carbothermic reduction in the chemistry of metal extraction (MO(s) + C(s) → M(s) + CO(g)) using carbon as a sacrificial agent has been used to smelt metals from diverse oxide ores since ancient times. Here, we paid attention to another aspect of the carbothermic reduction to prepare an activated carbon textile for high-rate-performance supercapacitors. On the basis of thermodynamic reducibility of metal oxides reported by Ellingham, we employed not carbon, but metal oxide as a sacrificial agent in order to prepare an activated carbon textile. We conformally coated ZnO on a bare cotton textile using atomic layer deposition, followed by pyrolysis at high temperature (C(s) + ZnO(s) → C'(s) + Zn(g) + CO(g)). We figured out that it leads to concurrent carbonization and activation in a chemical as well as mechanical way. Particularly, the combined effects of mechanical buckling and fracture that occurred between ZnO and cotton turned out to play an important role in carbonizing and activating the cotton textile, thereby significantly increasing surface area (nearly 10 times) compared with the cotton textile prepared without ZnO. The carbon textiles prepared by carbothermic reduction showed impressive combination properties of high power and energy densities (over 20-fold increase) together with high cyclic stability.

  8. A Paradox of Syntactic Priming: Why Response Tendencies Show Priming for Passives, and Response Latencies Show Priming for Actives

    PubMed Central

    Segaert, Katrien; Menenti, Laura; Weber, Kirsten; Hagoort, Peter

    2011-01-01

    Speakers tend to repeat syntactic structures across sentences, a phenomenon called syntactic priming. Although it has been suggested that repeating syntactic structures should result in speeded responses, previous research has focused on effects in response tendencies. We investigated syntactic priming effects simultaneously in response tendencies and response latencies for active and passive transitive sentences in a picture description task. In Experiment 1, there were priming effects in response tendencies for passives and in response latencies for actives. However, when participants' pre-existing preference for actives was altered in Experiment 2, syntactic priming occurred for both actives and passives in response tendencies as well as in response latencies. This is the first investigation of the effects of structure frequency on both response tendencies and latencies in syntactic priming. We discuss the implications of these data for current theories of syntactic processing. PMID:22022352

  9. Preparation of high surface area activated carbon from coconut shells using microwave heating.

    PubMed

    Yang, Kunbin; Peng, Jinhui; Srinivasakannan, C; Zhang, Libo; Xia, Hongying; Duan, Xinhui

    2010-08-01

    The present study attempts to utilize coconut shell to prepare activated carbon using agents such as steam, CO(2) and a mixture of steam-CO(2) with microwave heating. Experimental results show that the BET surface area of activated carbons irrespective of the activation agent resulted in surface area in excess of 2000 m(2)/g. The activation time using microwave heating is very much shorter, while the yield of the activated carbon compares well with the conventional heating methods. The activated carbon prepared using CO(2) activation has the largest BET surface area, however the activation time is approximately 2.5 times higher than the activation using steam or mixture of steam-CO(2). The chemical structure of activated carbons examined using Fourier transformed infra-red spectra (FTIR) did not show any variation in the surface functional groups of the activated carbon prepared using different activation agents.

  10. Investigating effectiveness of activated carbons of natural sources on various supercapacitors

    NASA Astrophysics Data System (ADS)

    Faisal, Md. Shahnewaz Sabit; Rahman, Muhammad M.; Asmatulu, Ramazan

    2016-04-01

    Activated carbon can be produced from natural sources, such as pistachio and acorn shells, which can be an inexpensive and sustainable sources of natural wastes for the energy storage devices, such as supercapacitors. The carbonaceous materials used in this study were carbonized at the temperatures of 700°C and 900°C after the stabilization process at 240°C for two hours. These shells showed approximately 60% carbon yield. Carbonized nutshells were chemically activated using1wt% potassium hydroxide (KOH). Activated carbon powders with polyvinylidene fluoride (PVdF) were used to construct carbon electrodes. A 1M of tetraethylammonium tetrafluoroborate (TEABF4) and propylene carbonate (PC) were used as electrolytes. Electrochemical techniques, such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the characterization of the supercapacitors. Scanning electron microscopy (SEM) was used to inspect the surface texture of the activated carbons. Activated pistachio shells carbonized at 700°C showed more porous surface texture than those carbonized at 900°C. Effects of the carbonization temperatures were studied for their electrochemical characteristics. The shells carbonized at 700°C showed better electrochemical characteristics compared to those carbonized at 900°C. The test results provided about 27,083 μF/g specific capacitance at a scan rate of 10mV/s. This study showed promising results for using these activated carbons produced from the natural wastes for supercapacitor applications.

  11. 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.

  12. An active carbon catalyst prevents coke formation from asphaltenes during the hydrocracking of vacuum residue

    SciTech Connect

    Fukuyama, H.; Terai, S.

    2007-07-01

    Active carbons were prepared by the steam activation of a brown coal char. The active carbon with mesopores showed greater adsorption selectivity for asphaltenes. The active carbon was effective at suppressing coke formation, even with the high hydrocracking conversion of vacuum residue. The analysis of the change in the composition of saturates, aromatics, resins, and asphaltenes in the cracked residue with conversion demonstrated the ability of active carbon to restrict the transformation of asphaltenes to coke. The active carbon that was richer in mesopores was presumably more effective at providing adsorption sites for the hydrocarbon free-radicals generated initially during thermal cracking to prevent them from coupling and polycondensing.

  13. Carbon nanotube based betulin formulation shows better efficacy against Leishmania parasite.

    PubMed

    Saudagar, Prakash; Dubey, Vikash Kumar

    2014-12-01

    We report a novel antileishmanial formulation of betulin (BET) attached to functionalized carbon nanotubes (f-CNTs). We conjugated betulin, a pentacyclic triterpenoid secondary metabolite, to carboxylic acid chains on f-CNTs to obtain BET attached functionalized carbon nanotubes (f-CNT-Bet). The drug release profile demonstrated a fairly slow release of BET. The in-vitro cytotoxicities of BET, f-CNT and f-CNT-BET on J774A.1 macrophage cell line were 211.05±7.14μg/ml; 24.67±3.11μg/ml and 72.63±6.14μg/ml, respectively. The IC50 of BET and f-CNT-BET against intracellular Leishmania donovani amastigotes were 8.33±0.41μg/ml and 0.69±0.08μg/ml, respectively. The results demonstrate better antileishmanial efficiency of f-CNT-BET formulation than BET alone and with no significant cytotoxicity observed on host cells.

  14. Adsorption of volatile organic compounds by pecan shell- and almond shell-based granular activated carbons.

    PubMed

    Bansode, R R; Losso, J N; Marshall, W E; Rao, R M; Portier, R J

    2003-11-01

    The objective of this research was to determine the effectiveness of using pecan and almond shell-based granular activated carbons (GACs) in the adsorption of volatile organic compounds (VOCs) of health concern and known toxic compounds (such as bromo-dichloromethane, benzene, carbon tetrachloride, 1,1,1-trichloromethane, chloroform, and 1,1-dichloromethane) compared to the adsorption efficiency of commercially used carbons (such as Filtrasorb 200, Calgon GRC-20, and Waterlinks 206C AW) in simulated test medium. The pecan shell-based GACs were activated using steam, carbon dioxide or phosphoric acid. An almond shell-based GAC was activated with phosphoric acid. Our results indicated that steam- or carbon dioxide-activated pecan shell carbons were superior in total VOC adsorption to phosphoric acid-activated pecan shell or almond shell carbons, inferring that the method of activation selected for the preparation of activated carbons affected the adsorption of VOCs and hence are factors to be considered in any adsorption process. The steam-activated, pecan shell carbon adsorbed more total VOCs than the other experimental carbons and had an adsorption profile similar to the two coconut shell-based commercial carbons, but had greater adsorption than the coal-based commercial carbon. All the carbons studied adsorbed benzene more effectively than the other organics. Pecan shell, steam-activated and acid-activated GACs showed higher adsorption of 1,1,1-trichloroethane than the other carbons studied. Multivariate analysis was conducted to group experimental carbons and commercial carbons based on their physical, chemical, and adsorptive properties. The results of the analysis conclude that steam-activated and acid-activated pecan shell carbons clustered together with coal-based and coconut shell-based commercial carbons, thus inferring that these experimental carbons could potentially be used as alternative sources for VOC adsorption in an aqueous environment.

  15. Aircraft measurements of black carbon vertical profiles show upper tropospheric variability and stability

    NASA Astrophysics Data System (ADS)

    Schwarz, Joshua P.; Weinzierl, Bernadett; Samset, Bjørn H.; Dollner, Maximilian; Heimerl, Katharina; Markovic, Milos Z.; Perring, Anne E.; Ziemba, Luke

    2017-01-01

    We present new data sets of black carbon (BC) aerosol mass mixing ratio (MMR) obtained from aircraft missions over North America, Europe, the Arctic, and the outflow region of Saharan Africa before and after trans-Atlantic transport. The data, collected from 2011 to 2013 with single-particle soot photometers, provide new insight into the variability and distribution of BC over global scales and refine understanding of AeroCom global model ensemble performance. The results indicate extensive global-scale longitudinal mixing of BC above altitude pressures as low as 400 hPa. They also constrain the absolute and temporal variability of upper tropospheric BC MMR and point to opportunities for new tests of global aerosol models in the upper troposphere. A comparison to the AeroCom Phase II results generally reinforces previous estimates of the ensemble performance, except that it also strengthens confidence that the ensemble actually is biased high in the Arctic in all seasons.

  16. Physicochemical effect of activation temperature on the sorption properties of pine shell activated carbon.

    PubMed

    Wasim, Agha Arslan; Khan, Muhammad Nasiruddin

    2017-03-01

    Activated carbons produced from a variety of raw materials are normally selective towards a narrow range of pollutants present in wastewater. This study focuses on shifting the selectivity of activated carbon from inorganic to organic pollutants using activation temperature as a variable. The material produced from carbonization of pine shells substrate was activated at 250°C and 850°C. Both adsorbents were compared with commercial activated carbon for the sorption of lead, cadmium, methylene blue, methyl blue, xylenol orange, and crystal violet. It was observed that carbon activated at 250°C was selective for lead and cadmium whereas the one activated at 850°C was selective for the organic dyes. The Fourier transform infrared spectroscopy study revealed that AC850 had less surface functional groups as compared to AC250. Point of zero charge and point of zero salt effect showed that AC250 had acidic groups at its surface. Scanning electron microscopy depicted that increase in activation temperature resulted in an increase in pore size of activated carbon. Both AC250 and AC850 followed pseudo-second-order kinetics. Temkin isotherm model was a best fit for empirical data obtained at equilibrium. The model also showed that sorption process for both AC250 and AC850 was physisorption.

  17. 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.

  18. 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

  19. Supercritical Carbon Dioxide Regeneration of Activated Carbon Loaded with Contaminants from Rocky Mountain Arsenal Well Water.

    DTIC Science & Technology

    1982-05-01

    15 111-7 GRANULAR ACTIVATED CARBON ADSORPTION ISOTHERMS THERMALLY REACTIVATED CARBON .............. 16 I IV-1 PROCESS FLOW DIAGRAM FOR... PROCESSING COST OF ACTIVATED CHARCOAL REGENERATION BY SUPERCRITICAL CARBON DIOXIDE PROCESS ........................... 25 l IV-4 SENSITIVITY OF GAC...regenerate adsorbents such as granular activated carbon loaded with a broad variety of organic adsorbates. This regeneration process uses a supercritical

  20. 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.

  1. Adsorption of Hydantoins on Activated Carbon,

    DTIC Science & Technology

    1985-05-01

    performed for single solute, bisolute, and trisolute solutions as well as an undiluted coal gasification wastewater containing predominantly hydantoin...hydantoin, 5,5-dimethylhydantoin, and 5-ethyl-5-methylhydantoin. Absorption using activated carbon did not appear to be an effective treatment process for the removal of hydantoins from the coal gasification wastewater.

  2. 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...

  3. 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...

  4. 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...

  5. A Boronic Acid Conjugate of Angiogenin that Shows ROS-Responsive Neuroprotective Activity.

    PubMed

    Hoang, Trish T; Smith, Thomas P; Raines, Ronald T

    2017-03-01

    Angiogenin (ANG) is a human ribonuclease that is compromised in patients with amyotrophic lateral sclerosis (ALS). ANG also promotes neovascularization, and can induce hemorrhage and encourage tumor growth. The causal neurodegeneration of ALS is associated with reactive oxygen species, which are also known to elicit the oxidative cleavage of carbon-boron bonds. We have developed a synthetic boronic acid mask that restrains the ribonucleolytic activity of ANG. The masked ANG does not stimulate endothelial cell proliferation but protects astrocytes from oxidative stress. By differentiating between the two dichotomous biological activities of ANG, this strategy could provide a viable pharmacological approach for the treatment of ALS.

  6. Different types of nitrogen deposition show variable effects on the soil carbon cycle process of temperate forests.

    PubMed

    Du, Yuhan; Guo, Peng; Liu, Jianqiu; Wang, Chunyu; Yang, Ning; Jiao, Zhenxia

    2014-10-01

    Nitrogen (N) deposition significantly affects the soil carbon (C) cycle process of forests. However, the influence of different types of N on it still remained unclear. In this work, ammonium nitrate was selected as an inorganic N (IN) source, while urea and glycine were chosen as organic N (ON) sources. Different ratios of IN to ON (1 : 4, 2 : 3, 3 : 2, 4 : 1, and 5 : 0) were mixed with equal total amounts and then used to fertilize temperate forest soils for 2 years. Results showed that IN deposition inhibited soil C cycle processes, such as soil respiration, soil organic C decomposition, and enzymatic activities, and induced the accumulation of recalcitrant organic C. By contrast, ON deposition promoted these processes. Addition of ON also resulted in accelerated transformation of recalcitrant compounds into labile compounds and increased CO2 efflux. Meanwhile, greater ON deposition may convert C sequestration in forest soils into C source. These results indicated the importance of the IN to ON ratio in controlling the soil C cycle, which can consequently change the ecological effect of N deposition.

  7. Supercapacitor Electrodes from Activated Carbon Monoliths and Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Dolah, B. N. M.; Othman, M. A. R.; Deraman, M.; Basri, N. H.; Farma, R.; Talib, I. A.; Ishak, M. M.

    2013-04-01

    Binderless monoliths of supercapacitor electrodes were prepared by the carbonization (N2) and activation (CO2) of green monoliths (GMs). GMs were made from mixtures of self-adhesive carbon grains (SACG) of fibers from oil palm empty fruit bunches and a combination of 5 & 6% KOH and 0, 5 & 6% carbon nanotubes (CNTs) by weight. The electrodes from GMs containing CNTs were found to have lower specific BET surface area (SBET). The electrochemical behavior of the supercapacitor fabricated using the prepared electrodes were investigated by electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD). In general an addition of CNTs into the GMs reduces the equivalent series resistance (ESR) value of the cells. A cell fabricated using electrodes from GM with 5% CNT and 5% KOH was found to have the largest reduction of ESR value than that from the others GMs containing CNT. The cell has steeper Warburg's slope than that from its respective non-CNT GM, which reflect the smaller resistance for electrolyte ions to move into pores of electrodes despite these electrodes having largest reduction in specific BET surface area. The cell also has the smallest reduction of specific capacitance (Csp) and maintains the specific power range despite a reduction in the specific energy range due to the CNT addition.

  8. Carbon Nanotubes Activate Limulus Amebocyte Lysate Coagulation by Interface Adsorption.

    PubMed

    Yang, Man; Nie, Xin; Meng, Jie; Liu, Jian; Sun, Zhiwei; Xu, Haiyan

    2017-03-15

    Limulus amebocyte lysate (LAL) assay is worldwide requested in the assessment of endotoxin contamination for biomaterials. As carbon nanotubes are one major nanomaterial with multiple potentials in biomedical application, here we investigate whether oxidized multiwalled carbon nanotubes (O-MWCNT) interferes the assessment by LAL assays. We showed that the endotoxin free O-MWCNT dispersing in aqueous solutions could activate both the gel-clotting and the end-point chromogenic LAL assay by converting coagulogen into coagulin through interfacial interactions between O-MWCNT and enzymes in the assays. In conclusion, the O-MWCNT could induce false positive results by activating the enzyme cascade of LAL.

  9. Decolorization of Cheddar cheese whey by activated carbon.

    PubMed

    Zhang, Yue; Campbell, Rachel; Drake, MaryAnne; Zhong, Qixin

    2015-05-01

    Colored Cheddar whey is a source for whey protein recovery and is decolorized conventionally by bleaching, which affects whey protein quality. Two activated carbons were studied in the present work as physical means of removing annatto (norbixin) in Cheddar cheese whey. The color and residual norbixin content of Cheddar whey were reduced by a higher level of activated carbon at a higher temperature between 25 and 55°C and a longer time. Activated carbon applied at 40g/L for 2h at 30°C was more effective than bleaching by 500mg/L of hydrogen peroxide at 68°C. The lowered temperature in activated-carbon treatments had less effect on protein structure as investigated for fluorescence spectroscopy and volatile compounds, particularly oxidation products, based on gas chromatography-mass spectrometry. Activated carbon was also reusable, removing more than 50% norbixin even after 10 times of regeneration, which showed great potential for decolorizing cheese whey.

  10. [Preparation and optimum process of walnut peel activated carbon by zinc chloride as activating agent].

    PubMed

    Liu, Xiao-hong; Wang, Xing-wei; Zhao, Bo; Lü, Jun-fang; Kang, Ni-na; Zhang, Yao-jun

    2014-12-01

    Walnut peel as raw material, zinc chloride was used as activating agent for preparation walnut peel activated carbon in the muffle furnace in this experiment, using orthogonal design. Yield, the specific surface area and iodine number of walnut peel activated carbon were determined at all designed experimental conditions and the optimum technological condition of preparation was obtained. By analysis of aperture, infrared spectra and the content of acidic group in surface with Boehm, walnut peel activated carbon of prepared at the optimum condition was characterized. The results showed the optimum technological parameters of preparation: activation temperature (600 °C), activation time (1 h), the concentration of zinc chloride (50%), the particle size (60 mesh). The specific surface area of walnut peel activated carbon obtained at optimum condition was mounting to 1258.05 m2 · g(-1), the ratio of medium porous 32.18%. Therefore, walnut peel can be used in the preparation of the high-quality activated carbon of large surface area. Agricultural wastes, as walnut peel, not only were implemented recycle, but also didn't make any pollution. Meanwhile, a cheap adsorbent was provided and it was of great significance to open a new source of activated carbon.

  11. Cooperative redox activation for carbon dioxide conversion

    NASA Astrophysics Data System (ADS)

    Lian, Zhong; Nielsen, Dennis U.; Lindhardt, Anders T.; Daasbjerg, Kim; Skrydstrup, Troels

    2016-12-01

    A longstanding challenge in production chemistry is the development of catalytic methods for the transformation of carbon dioxide into useful chemicals. Silane and borane promoted reductions can be fined-tuned to provide a number of C1-building blocks under mild conditions, but these approaches are limited because of the production of stoichiometric waste compounds. Here we report on the conversion of CO2 with diaryldisilanes, which through cooperative redox activation generate carbon monoxide and a diaryldisiloxane that actively participate in a palladium-catalysed carbonylative Hiyama-Denmark coupling for the synthesis of an array of pharmaceutically relevant diarylketones. Thus the disilane reagent not only serves as the oxygen abstracting agent from CO2, but the silicon-containing `waste', produced through oxygen insertion into the Si-Si bond, participates as a reagent for the transmetalation step in the carbonylative coupling. Hence this concept of cooperative redox activation opens up for new avenues in the conversion of CO2.

  12. 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.

  13. Role of nitrogen in pore development in activated carbon prepared by potassium carbonate activation of lignin

    NASA Astrophysics Data System (ADS)

    Tsubouchi, Naoto; Nishio, Megumi; Mochizuki, Yuuki

    2016-05-01

    The present work focuses on the role of nitrogen in the development of pores in activated carbon produced from lignin by K2CO3 activation, employing a fixed bed reactor under a high-purity He stream at temperatures of 500-900 °C. The specific surface area and pore volume obtained by activation of lignin alone are 230 m2/g and 0.13 cm3/g at 800 °C, and 540 m2/g and 0.31 cm3/g at 900 °C, respectively. Activation of a mixture of lignin and urea provides a significant increase in the surface area and volume, respectively reaching 3300-3400 m2/g and 2.0-2.3 cm3/g after holding at 800-900 °C for 1 h. Heating a lignin/urea/K2CO3 mixture leads to a significant decrease in the yield of released N-containing gases compared to the results for urea alone and a lignin/urea mixture, and most of the nitrogen in the urea is retained in the solid phase. X-ray photoelectron spectroscopy and X-ray diffraction analyses clearly show that part of the remaining nitrogen is present in heterocyclic structures (for example, pyridinic and pyrrolic nitrogen), and the rest is contained as KOCN at ≤600 °C and as KCN at ≥700 °C, such that the latter two compounds can be almost completely removed by water washing. The fate of nitrogen during heating of lignin/urea/K2CO3 and role of nitrogen in pore development in activated carbon are discussed on the basis of the results mentioned above.

  14. Activation of peroxymonosulfate by graphitic carbon nitride loaded on activated carbon for organic pollutants degradation.

    PubMed

    Wei, Mingyu; Gao, Long; Li, Jun; Fang, Jia; Cai, Wenxuan; Li, Xiaoxia; Xu, Aihua

    2016-10-05

    Graphitic carbon nitride supported on activated carbon (g-C3N4/AC) was prepared through an in situ thermal approach and used as a metal free catalyst for pollutants degradation in the presence of peroxymonosulfate (PMS) without light irradiation. It was found that g-C3N4 was highly dispersed on the surface of AC with the increase of surface area and the exposition of more edges and defects. The much easier oxidation of C species in g-C3N4 to CO was also observed from XPS spectra. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the g-C3N4/AC catalyst within 20min with PMS, while g-C3N4+PMS and AC+PMS showed no significant activity for the reaction. The performance of the catalyst was significantly influenced by the amount of g-C3N4 loaded on AC; but was nearly not affected by the initial solution pH and reaction temperature. In addition, the catalysts presented good stability. A nonradical mechanism accompanied by radical generation (HO and SO4(-)) in AO7 oxidation was proposed in the system. The CO groups play a key role in the process; while the exposure of more N-(C)3 group can further increase its electron density and basicity. This study can contribute to the development of green materials for sustainable remediation of aqueous organic pollutants.

  15. Alkaloids from the seeds of Peganum harmala showing antiplasmodial and vasorelaxant activities.

    PubMed

    Astulla, Adil; Zaima, Kazumasa; Matsuno, Yosuke; Hirasawa, Yusuke; Ekasari, Wiwied; Widyawaruyanti, Aty; Zaini, Noor Cholies; Morita, Hiroshi

    2008-10-01

    Bioassay-guided purification from the seeds of Peganum harmala led to the isolation of harmine (1), harmaline (2), vasicinone (3), and deoxyvasicinone (4). Harmine (1) and harmaline (2) showed a moderate in vitro antiplasmodial activity against Plasmodium falciparum. Quinazoline alkaloid, vasicinone (3), showed a vasorelaxant activity against phenylephrine-induced contraction of isolated rat aorta.

  16. Computationally designed variants of Escherichia coli chorismate mutase show altered catalytic activity.

    PubMed

    Lassila, Jonathan Kyle; Keeffe, Jennifer R; Oelschlaeger, Peter; Mayo, Stephen L

    2005-04-01

    Computational protein design methods were used to predict five variants of monofunctional Escherichia coli chorismate mutase expected to maintain catalytic activity. The variants were tested experimentally and three active site mutants exhibited catalytic activity similar to or greater than the wild-type enzyme. One mutant, Ala32Ser, showed increased catalytic efficiency.

  17. Kinetics of adsorption with granular, powdered, and fibrous activated carbon

    SciTech Connect

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

    1997-08-01

    The properties of three different types of activated carbon, fibrous, powdered, and granular, were investigated theoretically and experimentally. The adsorption rate of the activated carbon fiber was found to be two orders of magnitude higher than that of the granular activated carbon, and one order of magnitude higher than that of the powdered activated carbon. Diffusion coefficients of methylene blue in the fibrous, powdered, and granular activated carbons were determined experimentally. A new method for estimating the meso- and macropore surface areas in these carbons was proposed.

  18. 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.

  19. 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.

  20. Simple fabrication of carbon/TiO2 composite nanotubes showing dual functions with adsorption and photocatalytic decomposition of Rhodamine B.

    PubMed

    Im, Ji Hyuk; Yang, Seung Jae; Yun, Chang Hun; Park, Chong Rae

    2012-01-27

    Carbon/TiO2 composite nanotubes were fabricated via a very simple electrospinning process and their dual functionalities of adsorptivity and photocatalytic activity were evaluated using Rhodamine B (RhB) as a model organic pollutant. A poly(vinyl alcohol) (PVA) aqueous solution was directly electrospun into a coagulation bath containing titanium (IV) tetraisopropoxide (TTIP) solution so that PVA-core/TiO2-shell composite nanofibers were formed through the in situ sol-gel reaction of TTIP. The carbon/TiO2 composite nanotubes were then fabricated by heat treatment of composite nanofibers under nitrogen atmosphere. By using several characterization methods, we confirmed that the resultant nanotubes consisted of anatase TiO2 nanocrystallites embedded in a carbonaceous matrix. The prepared nanotubes exhibited fast adsorption of RhB with high capacity compared with a commercial porous carbon, and they also showed the photocatalytic decomposition activity for the dye molecules under UV irradiation comparable to the degradation by P-25 and ST-01 (commercial TiO2). Finally, the carbon/TiO2 composite nanotubes exhibited several cycle performances of adsorption-photodegradation for RhB. This indicates that the composite nanotubes can adsorb and photodecompose organic pollutants repeatedly without additional activating processes.

  1. Simple fabrication of carbon/TiO2 composite nanotubes showing dual functions with adsorption and photocatalytic decomposition of Rhodamine B

    NASA Astrophysics Data System (ADS)

    Im, Ji Hyuk; Yang, Seung Jae; Yun, Chang Hun; Park, Chong Rae

    2012-01-01

    Carbon/TiO2 composite nanotubes were fabricated via a very simple electrospinning process and their dual functionalities of adsorptivity and photocatalytic activity were evaluated using Rhodamine B (RhB) as a model organic pollutant. A poly(vinyl alcohol) (PVA) aqueous solution was directly electrospun into a coagulation bath containing titanium (IV) tetraisopropoxide (TTIP) solution so that PVA-core/TiO2-shell composite nanofibers were formed through the in situ sol-gel reaction of TTIP. The carbon/TiO2 composite nanotubes were then fabricated by heat treatment of composite nanofibers under nitrogen atmosphere. By using several characterization methods, we confirmed that the resultant nanotubes consisted of anatase TiO2 nanocrystallites embedded in a carbonaceous matrix. The prepared nanotubes exhibited fast adsorption of RhB with high capacity compared with a commercial porous carbon, and they also showed the photocatalytic decomposition activity for the dye molecules under UV irradiation comparable to the degradation by P-25 and ST-01 (commercial TiO2). Finally, the carbon/TiO2 composite nanotubes exhibited several cycle performances of adsorption-photodegradation for RhB. This indicates that the composite nanotubes can adsorb and photodecompose organic pollutants repeatedly without additional activating processes.

  2. 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.

  3. Carboxylated Short Single-Walled Carbon Nanotubes But Not Plain and Multi-walled Short Carbon Nanotubes Show in vitro Genotoxicity

    PubMed Central

    Mrakovcic, Maria; Meindl, Claudia; Leitinger, Gerd; Roblegg, Eva; Fröhlich, Eleonore

    2015-01-01

    Long carbon nanotubes (CNTs) resemble asbestos fibers due to their high length to diameter ratio and they thus have genotoxic effects. Another parameter that might explain their genotoxic effects is contamination with heavy metal ions. On the other hand, short (1–2 μm) CNTs do not resemble asbestos fibers, and, once purified from contaminations, they might be suitable for medical applications. To identify the role of fiber thickness and surface properties on genotoxicity, well-characterized short pristine and carboxylated single-walled (SCNTs) and multi-walled (MCNTs) CNTs of different diameters were studied for cytotoxicity, the cell’s response to oxidative stress (immunoreactivity against hemoxygenase 1 and glutathione levels), and in a hypoxanthine guanine phosphoribosyltransferase (HPRT) assay using V79 chinese hamster fibroblasts and human lung adenocarcinoma A549 cells. DNA repair was demonstrated by measuring immunoreactivity against activated histone H2AX protein. The number of micronuclei as well as the number of multinucleated cells was determined. CNTs acted more cytotoxic in V79 than in A549 cells. Plain and carboxylated thin (<8 nm) SCNTs and MCNTs showed greater cytotoxic potential and carboxylated CNTs showed indication for generating oxidative stress. Multi-walled CNTs did not cause HPRT mutation, micronucleus formation, DNA damage, interference with cell division, and oxidative stress. Carboxylated, but not plain, SCNTs showed indication for in vitro DNA damage according to increase of H2AX-immunoreactive cells and HPRT mutation. Although short CNTs presented a low in vitro genotoxicity, functionalization of short SCNTs can render these particles genotoxic. PMID:25505129

  4. 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.

  5. Bioindication potential of carbonic anhydrase activity in anemones and corals.

    PubMed

    Gilbert, A L; Guzmán, H M

    2001-09-01

    Activity levels of carbonic anhydrase (CA) were assessed in anemones Condylactis gigantea and Stichodactyla helianthus with laboratory exposures to copper, nickel, lead, and vanadium, and also in animals collected from polluted vs pristine field sites. CA activity was found to be decreased with increase in metal concentration and also in animals collected from the polluted field site. Preliminary assessments to adapt the CA assay for use in the widespread coral Montastraea cavernosa show decreased CA activity in specimens from the polluted field site and provide an avenue for future research aimed at more thoroughly describing coral CA activity for potential application in bioindication.

  6. 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

  7. Effects of organic carbon sequestration strategies on soil enzymatic activities

    NASA Astrophysics Data System (ADS)

    Puglisi, E.; Suciu, N.; Botteri, L.; Ferrari, T.; Coppolecchia, D.; Trevisan, M.; Piccolo, A.

    2009-04-01

    Greenhouse gases emissions can be counterbalanced with proper agronomical strategies aimed at sequestering carbon in soils. These strategies must be tested not only for their ability in reducing carbon dioxide emissions, but also for their impact on soil quality: enzymatic activities are related to main soil ecological quality, and can be used as early and sensitive indicators of alteration events. Three different strategies for soil carbon sequestration were studied: minimum tillage, protection of biodegradable organic fraction by compost amendment and oxidative polimerization of soil organic matter catalyzed by biometic porfirins. All strategies were compared with a traditional agricultural management based on tillage and mineral fertilization. Experiments were carried out in three Italian soils from different pedo-climatic regions located respectively in Piacenza, Turin and Naples and cultivated with maize or wheat. Soil samples were taken for three consecutive years after harvest and analyzed for their content in phosphates, ß-glucosidase, urease and invertase. An alteration index based on these enzymatic activities levels was applied as well. The biomimetic porfirin application didn't cause changes in enzymatic activities compared to the control at any treatment or location. Enzymatic activities were generally higher in the minimum tillage and compost treatment, while differences between location and date of samplings were limited. Application of the soil alteration index based on enzymatic activities showed that soils treated with compost or subjected to minimum tillage generally have a higher biological quality. The work confirms the environmental sustainability of the carbon sequestering agronomical practices studied.

  8. 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.

  9. 78 FR 13894 - Certain Activated Carbon From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-01

    ... COMMISSION Certain Activated Carbon From China Determination On the basis of the record \\1\\ developed in the... antidumping duty order on certain activated carbon from China would be likely to lead to continuation or... USITC Publication 4381 (February 2013), entitled Certain Activated Carbon from China: Investigation...

  10. Carbon Monoxide Dehydrogenase Activity in Bradyrhizobium japonicum

    PubMed Central

    Lorite, María J.; Tachil, Jörg; Sanjuán, Juán; Meyer, Ortwin; Bedmar, Eulogio J.

    2000-01-01

    Bradyrhizobium japonicum strain 110spc4 was capable of chemolithoautotrophic growth with carbon monoxide (CO) as a sole energy and carbon source under aerobic conditions. The enzyme carbon monoxide dehydrogenase (CODH; EC 1.2.99.2) has been purified 21-fold, with a yield of 16% and a specific activity of 58 nmol of CO oxidized/min/mg of protein, by a procedure that involved differential ultracentrifugation, anion-exchange chromatography, hydrophobic interaction chromatography, and gel filtration. The purified enzyme gave a single protein and activity band on nondenaturing polyacrylamide gel electrophoresis and had a molecular mass of 230,000 Da. The 230-kDa enzyme was composed of large (L; 75-kDa), medium (M; 28.4-kDa), and small (S; 17.2-kDa) subunits occurring in heterohexameric (LMS)2 subunit composition. The 75-kDa polypeptide exhibited immunological cross-reactivity with the large subunit of the CODH of Oligotropha carboxidovorans. The B. japonicum enzyme contained, per mole, 2.29 atoms of Mo, 7.96 atoms of Fe, 7.60 atoms of labile S, and 1.99 mol of flavin. Treatment of the enzyme with iodoacetamide yielded di(carboxamidomethyl)molybdopterin cytosine dinucleotide, identifying molybdopterin cytosine dinucleotide as the organic portion of the B. japonicum CODH molybdenum cofactor. The absorption spectrum of the purified enzyme was characteristic of a molybdenum-containing iron-sulfur flavoprotein. PMID:10788353

  11. Carbon monoxide dehydrogenase activity in Bradyrhizobium japonicum.

    PubMed

    Lorite, M J; Tachil, J; Sanjuán, J; Meyer, O; Bedmar, E J

    2000-05-01

    Bradyrhizobium japonicum strain 110spc4 was capable of chemolithoautotrophic growth with carbon monoxide (CO) as a sole energy and carbon source under aerobic conditions. The enzyme carbon monoxide dehydrogenase (CODH; EC 1.2.99.2) has been purified 21-fold, with a yield of 16% and a specific activity of 58 nmol of CO oxidized/min/mg of protein, by a procedure that involved differential ultracentrifugation, anion-exchange chromatography, hydrophobic interaction chromatography, and gel filtration. The purified enzyme gave a single protein and activity band on nondenaturing polyacrylamide gel electrophoresis and had a molecular mass of 230,000 Da. The 230-kDa enzyme was composed of large (L; 75-kDa), medium (M; 28.4-kDa), and small (S; 17.2-kDa) subunits occurring in heterohexameric (LMS)(2) subunit composition. The 75-kDa polypeptide exhibited immunological cross-reactivity with the large subunit of the CODH of Oligotropha carboxidovorans. The B. japonicum enzyme contained, per mole, 2.29 atoms of Mo, 7.96 atoms of Fe, 7.60 atoms of labile S, and 1.99 mol of flavin. Treatment of the enzyme with iodoacetamide yielded di(carboxamidomethyl)molybdopterin cytosine dinucleotide, identifying molybdopterin cytosine dinucleotide as the organic portion of the B. japonicum CODH molybdenum cofactor. The absorption spectrum of the purified enzyme was characteristic of a molybdenum-containing iron-sulfur flavoprotein.

  12. 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

  13. Surface modification of activated carbon for enhanced adsorption of perfluoroalkyl acids from aqueous solutions.

    PubMed

    Zhi, Yue; Liu, Jinxia

    2016-02-01

    The objective of the research was to examine the effect of increasing carbon surface basicity on uptake of perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) by activated carbon. Granular activated carbons made from coal, coconut shell, wood, and phenolic-polymer-based activated carbon fibers were modified through high-temperature and ammonia gas treatments to facilitate systematical evaluation of the impact of basicity of different origins. Comparison of adsorption isotherms and adsorption distribution coefficients showed that the ammonia gas treatment was more effective than the high-temperature treatment in enhancing surface basicity. The resultant higher point of zero charges and total basicity (measured by total HCl uptake) correlated with improved adsorption affinity for PFOS and PFOA. The effectiveness of surface modification to enhance adsorption varied with carbon raw material. Wood-based carbons and activated carbon fibers showed enhancement by one to three orders of magnitudes while other materials could experience reduction in adsorption towards either PFOS or PFOA.

  14. Activated carbons derived from oil palm empty-fruit bunches: application to environmental problems.

    PubMed

    Alam, Md Zahangir; Muyibi, Suleyman A; Mansor, Mariatul F; Wahid, Radziah

    2007-01-01

    Activated carbons derived from oil palm empty fruit bunches (EFB) were investigated to find the suitability of its application for removal of phenol in aqueous solution through adsorption process. Two types of activation namely; thermal activation at 300, 500 and 800 degrees C and physical activation at 150 degrees C (boiling treatment) were used for the production of the activated carbons. A control (untreated EFB) was used to compare the adsorption capacity of the activated carbons produced from these processes. The results indicated that the activated carbon derived at the temperature of 800 degrees C showed maximum absorption capacity in the aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon at 800 degrees C. It was observed that the adsorption capacity was higher at lower values of pH (2-3) and higher value of initial concentration of phenol (200-300 mg/L). The equilibrium data fitted better with the Freundlich adsorption isotherm compared to the Langmuir. Kinetic studies of phenol adsorption onto activated carbons were also studied to evaluate the adsorption rate. The estimated cost for production of activated carbon from EFB was shown in lower price (USD 0.50/kg of activated carbon) compared the activated carbon from other sources and processes.

  15. Decolorization of sugar syrups using commercial and sugar beet pulp based activated carbons.

    PubMed

    Mudoga, H L; Yucel, H; Kincal, N S

    2008-06-01

    Sugar syrup decolorization was studied using two commercial and eight beet pulp based activated carbons. In an attempt to relate decolorizing performances to other characteristics, surface areas, pore volumes, bulk densities and ash contents of the carbons in the powdered form; pH and electrical conductivities of their suspensions and their color adsorption properties from iodine and molasses solution were determined. The color removal capabilities of all carbons were measured at 1/100 (w/w) dosage, and isotherms were determined on better samples. The two commercial activated carbons showed different decolorization efficiencies; which could be related to their physical and chemical properties. The decolorization efficiency of beet pulp carbon prepared at 750 degrees C and activated for 5h using CO2 was much better than the others and close to the better one of the commercial activated carbons used. It is evident that beet pulp is an inexpensive potential precursor for activated carbons for use in sugar refining.

  16. 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.

  17. Comparison of toluene adsorption among granular activated carbon and different types of activated carbon fibers (ACFs).

    PubMed

    Balanay, Jo Anne G; Crawford, Shaun A; Lungu, Claudiu T

    2011-10-01

    Activated carbon fiber (ACF) has been demonstrated to be a good adsorbent for the removal of organic vapors in air. Some ACF has a comparable or larger surface area and higher adsorption capacity when compared with granular activated carbon (GAC) commonly used in respiratory protection devices. ACF is an attractive alternative adsorbent to GAC because of its ease of handling, light weight, and decreasing cost. ACF may offer the potential for short-term respiratory protection for first responders and emergency personnel. This study compares the critical bed depths and adsorption capacities for toluene among GAC and ACF of different forms and surface areas. GAC and ACF in cloth (ACFC) and felt (ACFF) forms were challenged in stainless steel chambers with a constant concentration of 500 ppm toluene via conditioned air at 25°C, 50% RH, and constant airflow (7 L/min). Breakthrough data were obtained for each adsorbent using gas chromatography with flame ionization detector. Surface areas of each adsorbent were determined using a physisorption analyzer. Results showed that the critical bed depth of GAC is 275% higher than the average of ACFC but is 55% lower than the average of ACFF. Adsorption capacity of GAC (with a nominal surface area of 1800 m(2)/g) at 50% breakthrough is 25% higher than the average of ACF with surface area of 1000 m(2)/g, while the rest of ACF with surface area of 1500 m(2)/g and higher have 40% higher adsorption capacities than GAC. ACFC with higher surface area has the smallest critical bed depth and highest adsorption capacity, which makes it a good adsorbent for thinner and lighter respirators. We concluded that ACF has great potential for application in respiratory protection considering its higher adsorption capacity and lower critical bed depth in addition to its advantages over GAC, particularly for ACF with higher surface area.

  18. Activated carbon briquettes from biomass materials.

    PubMed

    Amaya, Alejandro; Medero, Natalia; Tancredi, Néstor; Silva, Hugo; Deiana, Cristina

    2007-05-01

    Disposal of biomass wastes, produced in different agricultural activities, is frequently an environmental problem. A solution for such situation is the recycling of these residues for the production of activated carbon, an adsorbent which has several applications, for instance in the elimination of contaminants. For some uses, high mechanical strength and good adsorption characteristics are required. To achieve this, carbonaceous materials are conformed as pellets or briquettes, in a process that involves mixing and pressing of char with adhesive materials prior to activation. In this work, the influence of the operation conditions on the mechanical and surface properties of briquettes was studied. Eucalyptus wood and rice husk from Uruguay were used as lignocellulosic raw materials, and concentrated grape must from Cuyo Region-Argentina, as a binder. Different wood:rice and solid:binder ratios were used to prepare briquettes in order to study their influence on mechanical and surface properties of the final products.

  19. Cooperative redox activation for carbon dioxide conversion

    PubMed Central

    Lian, Zhong; Nielsen, Dennis U.; Lindhardt, Anders T.; Daasbjerg, Kim; Skrydstrup, Troels

    2016-01-01

    A longstanding challenge in production chemistry is the development of catalytic methods for the transformation of carbon dioxide into useful chemicals. Silane and borane promoted reductions can be fined-tuned to provide a number of C1-building blocks under mild conditions, but these approaches are limited because of the production of stoichiometric waste compounds. Here we report on the conversion of CO2 with diaryldisilanes, which through cooperative redox activation generate carbon monoxide and a diaryldisiloxane that actively participate in a palladium-catalysed carbonylative Hiyama-Denmark coupling for the synthesis of an array of pharmaceutically relevant diarylketones. Thus the disilane reagent not only serves as the oxygen abstracting agent from CO2, but the silicon-containing ‘waste', produced through oxygen insertion into the Si–Si bond, participates as a reagent for the transmetalation step in the carbonylative coupling. Hence this concept of cooperative redox activation opens up for new avenues in the conversion of CO2. PMID:27981967

  20. Adsorbed natural gas storage with activated carbon

    SciTech Connect

    Sun, Jian; Brady, T.A.; Rood, M.J.

    1996-12-31

    Despite technical advances to reduce air pollution emissions, motor vehicles still account for 30 to 70% emissions of all urban air pollutants. The Clean Air Act Amendments of 1990 require 100 cities in the United States to reduce the amount of their smog within 5 to 15 years. Hence, auto emissions, the major cause of smog, must be reduced 30 to 60% by 1998. Natural gas con be combusted with less pollutant emissions. Adsorbed natural gas (ANG) uses adsorbents and operates with a low storage pressure which results in lower capital costs and maintenance. This paper describes the production of an activated carbon adsorbent produced from an Illinois coal for ANG.

  1. Charcoal and activated carbon at elevated pressure

    SciTech Connect

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

    1995-12-01

    High quality charcoal has been produced with very high yields of 50% to 60% from macadamia nut and kukui nut shells and of 44% to 47% from Eucalyptus and Leucaena wood in a bench scale unit at elevated pressure on a 2 to 3 hour cycle, compared to commercial practice of 25% to 30% yield on a 7 to 12 day operating cycle. Neither air pollution nor tar is produced by the process. The effects of feedstock pretreatments with metal additives on charcoal yield are evaluated in this paper. Also, the influences of steam and air partial pressure and total pressure on yields of activated carbon from high yield charcoal are presented.

  2. Studies on Supercapacitor Electrode Material from Activated Lignin-Derived Mesoporous Carbon

    SciTech Connect

    Saha, Dipendu; Li, Yunchao; Bi, Zhonghe; Chen, Jihua; Keum, Jong Kahk; Hensley, Dale K; Grappe, Hippolyte A.; Meyer III, Harry M; Dai, Sheng; Paranthaman, Mariappan Parans; Naskar, Amit K

    2014-01-01

    We synthesized mesoporous carbon from pre-cross-linked lignin gel impregnated with a surfactant as the pore-forming agent, and then activated the carbon through physical and chemical methods to obtain activated mesoporous carbon. The activated mesoporous carbons exhibited 1.5- to 6-fold increases in porosity with a maximum BET specific surface area of 1148 m2/g and a pore volume of 1.0 cm3/g. Slow physical activation helped retain dominant mesoporosity; however, aggressive chemical activation caused some loss of the mesopore volume fraction. Plots of cyclic voltammetric data with the capacitor electrode made from these carbons showed an almost rectangular curve depicting the behavior of ideal double-layer capacitance. Although the pristine mesoporous carbon exhibited the same range of surface-area-based capacitance as that of other known carbon-based supercapacitors, activation decreased the surface-area-based specific capacitance and increased the gravimetric-specific capacitance of the mesoporous carbons. Surface activation lowered bulk density and electrical conductivity. Warburg impedance as a vertical tail in the lower frequency domain of Nyquist plots supported good supercapacitor behavior for the activated mesoporous carbons. Our work demonstrated that biomass-derived mesoporous carbon materials continue to show potential for use in specific electrochemical applications.

  3. Water purification by sulfide-containing activated carbon.

    PubMed

    Oeste, F D; Haas, R; Kaminski, L

    2000-03-01

    We investigated a new kind of activated carbon named gaiasafe-Formstoff as an agent for powerful heavy metal reduction. This activated carbon contains highly dispersed sulfide compounds. Our investigations with lead containing wastewaters showed an outstanding metal sulfide precipitation power of the new agent. The lead reduction rates are independent of wastewater parameters like lead concentration and complexing agent concentration. Contacted as powder or as a fixed bed with wastewater gaiasafe-Formstoff showed the best cleaning capacity in comparison to all other agents tested. Investigations with gaiasafe-Formstoff about its ability to reduce the contents of further heavy metals in wastewater are under way. The gaiasafe-Formstoff reaction products with wastewater represent an energy-rich and raw material-rich resource when fed to metallurgical processes.

  4. Production of activated carbon from TCR char

    NASA Astrophysics Data System (ADS)

    Stenzel, Fabian; Heberlein, Markus; Klinner, Tobias; Hornung, Andreas

    2016-04-01

    The utilization of char for adsorptive purposes is known since the 18th century. At that time the char was made of wood or bones and used for decoloration of fluids. In the 20th century the production of activated carbon in an industrial scale was started. The today's raw materials for activated carbon production are hard coal, peat, wood or coconut shells. All these materials entail costs especially the latter. Thus, the utilization of carbon rich residues (biomass) is an interesting economic opportunity because it is available for no costs or even can create income. The char is produced by thermo-catalytic reforming (TCR®). This process is a combination of an intermediate pyrolysis and subsequently a reforming step. During the pyrolysis step the material is decomposed in a vapor and a solid carbon enriched phase. In the second step the vapor and the solid phase get in an intensive contact and the quality of both materials is improved via the reforming process. Subsequently, the condensables are precipitated from the vapor phase and a permanent gas as well as oil is obtained. Both are suitable for heat and power production which is a clear advantage of the TCR® process. The obtained biochar from the TCR® process has special properties. This material has a very low hydrogen and oxygen content. Its stability is comparable to hard coal or anthracite. Therefore it consists almost only of carbon and ash. The latter depends from input material. Furthermore the surface structure and area can be influenced during the reforming step. Depending from temperature and residence time the number of micro pores and the surface area can be increased. Preliminary investigations with methylene blue solution have shown that a TCR® char made of digestate from anaerobic digestion has adsorptive properties. The decoloration of the solution was achieved. A further influencing factor of the adsorption performance is the particle size. Based on the results of the preliminary tests a

  5. 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.

  6. Waste management activities and carbon emissions in Africa.

    PubMed

    Couth, R; Trois, C

    2011-01-01

    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. 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...

  8. 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.

  9. Preparation of activated carbons from bituminous coal pitches

    NASA Astrophysics Data System (ADS)

    Gañan, J.; González-García, C. M.; González, J. F.; Sabio, E.; Macías-García, A.; Díaz-Díez, M. A.

    2004-11-01

    High-porosity carbons were prepared from bituminous coal pitches by combining chemical and physical activation. The chemical activation process consisted of potassium hydroxide impregnation followed by carbonization in nitrogen atmosphere. The effect of the KOH impregnation ratio on the surface area and pore volumes evolution of the carbons derived from mesophase pitch was studied. The optimum KOH:pitch ratio was fixed to realize a physical activation process in order to increase the textural parameters of the KOH-activated carbons. Physical activation was performed by carbonizing the KOH-activated carbons followed by gasifying with air. The influence of the carbonization temperature and the residence time of the gasification with air were explored to optimize those preparation parameters.

  10. Adsorption of metal ions by pecan shell-based granular activated carbons.

    PubMed

    Bansode, R R; Losso, J N; Marshall, W E; Rao, R M; Portier, R J

    2003-09-01

    The present investigation was undertaken to evaluate the adsorption effectiveness of pecan shell-based granular activated carbons (GACs) in removing metal ions (Cu(2+), Pb(2+), Zn(2+)) commonly found in municipal and industrial wastewater. Pecan shells were activated by phosphoric acid, steam or carbon dioxide activation methods. Metal ion adsorption of shell-based GACs was compared to the metal ion adsorption of a commercial carbon, namely, Calgon's Filtrasorb 200. Adsorption experiments were conducted using solutions containing all three metal ions in order to investigate the competitive effects of the metal ions as would occur in contaminated wastewater. The results obtained from this study showed that acid-activated pecan shell carbon adsorbed more lead ion and zinc ion than any of the other carbons, especially at carbon doses of 0.2-1.0%. However, steam-activated pecan shell carbon adsorbed more copper ion than the other carbons, particularly using carbon doses above 0.2%. In general, Filtrasorb 200 and carbon dioxide-activated pecan shell carbons were poor metal ion adsorbents. The results indicate that acid- and steam-activated pecan shell-based GACs are effective metal ion adsorbents and can potentially replace typical coal-based GACs in treatment of metal contaminated wastewater.

  11. A humanized anti-M2 scFv shows protective in vitro activity against influenza

    SciTech Connect

    Bradbury, Andrew M; Velappan, Nileena; Schmidt, Jurgen G

    2008-01-01

    M2 is one of the most conserved influenza proteins, and has been widely prospected as a potential universal vaccine target, with protection predominantly mediated by antibodies. In this paper we describe the creation of a humanized single chain Fv from 14C2, a potent monoclonal antibody against M2. We show that the humanized scFv demonstrates similar activity to the parental mAb: it is able to recognize M2 in its native context on cell surfaces and is able to show protective in vitro activity against influenza, and so represents a potential lead antibody candidate for universal prophylactic or therapeutic intervention in influenza.

  12. 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...

  13. 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%.

  14. Activated Carbon Fibers For Gas Storage

    SciTech Connect

    Burchell, Timothy D; Contescu, Cristian I; Gallego, Nidia C

    2017-01-01

    The advantages of Activated Carbon Fibers (ACF) over Granular Activated Carbon (GAC) are reviewed and their relationship to ACF structure and texture are discussed. These advantages make ACF very attractive for gas storage applications. Both adsorbed natural gas (ANG) and hydrogen gas adsorption performance are discussed. The predicted and actual structure and performance of lignin-derived ACF is reviewed. The manufacture and performance of ACF derived monolith for potential automotive natural gas (NG) storage applications is reported Future trends for ACF for gas storage are considered to be positive. The recent improvements in NG extraction coupled with the widespread availability of NG wells means a relatively inexpensive and abundant NG supply in the foreseeable future. This has rekindled interest in NG powered vehicles. The advantages and benefit of ANG compared to compressed NG offer the promise of accelerated use of ANG as a commuter vehicle fuel. It is to be hoped the current cost hurdle of ACF can be overcome opening ANG applications that take advantage of the favorable properties of ACF versus GAC. Lastly, suggestions are made regarding the direction of future work.

  15. Electrochemical activation of carbon nanotube/polymer composites.

    PubMed

    Sánchez, Samuel; Fàbregas, Esteve; Pumera, Martin

    2009-01-07

    Electrochemical activation of carbon nanotube/polysulfone composite electrodes for enhanced heterogeneous electron transfer is studied. The physicochemical insight into the electrochemical activation of carbon nanotube/polymer composites was provided by transmission electron microscopy, Raman spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Dopamine, ascorbic acid, NADH, and ferricyanide are used as a model redox system for evaluating the performance of activated carbon nanotube/polymer composite electrodes. We demonstrate that polymer wrapping of carbon nanotubes is subject to defects and to partial removal during activation. Such tunable activation of electrodes would enable on-demand activation of electrodes for satisfying the needs of sensing or energy storage devices.

  16. Nano-sized Mn-doped activated carbon aerogel as electrode material for electrochemical capacitor: effect of activation conditions.

    PubMed

    Lee, Yoon Jae; Park, Hai Woong; Park, Sunyoung; Song, In Kyu

    2012-07-01

    Carbon aerogel (CA) was prepared by a sol-gel polymerization of resorcinol and formaldehyde, and a series of activated carbon aerogels (ACA-KOH-X, X = 0, 0.3, 0.7, 1, and 2) were then prepared by a chemical activation using different amount of potassium hydroxide (X represented weight ratio of KOH with respect to CA). Specific capacitances of activated carbon aerogels were measured by cyclic voltammetry and galvanostatic charge/discharge methods in 6 M KOH electrolyte. Among the samples prepared, ACA-KOH-0.7 showed the highest specific capacitance (149 F/g). In order to combine excellent electrochemical performance of activated carbon aerogel with pseudocapacitive property of manganese oxide, 7 wt% Mn was doped on activated carbon aerogel (Mn/ACA-KOH-0.7) by an incipient wetness impregnation method. For comparison, 7 wt% Mn was also impregnated on carbon aerogel (Mn/ACA-KOH-0) by the same method. It was revealed that 7 wt% Mn-doped activated carbon aerogel (Mn/ACA-KOH-0.7) showed higher specific capacitance than 7 wt% Mn-doped carbon aerogel (Mn/ACA-KOH-0) (178 F/g vs. 98 F/g). The enhanced capacitance of Mn/ACA-KOH-0.7 was attributed to the outstanding electric properties of activated carbon aerogel as well as the faradaic redox reactions of manganese oxide.

  17. Enhanced mercuric chloride adsorption onto sulfur-modified activated carbons derived from waste tires.

    PubMed

    Yuan, Chung-Shin; Wang, Guangzhi; Xue, Sheng-Han; Ie, Iau-Ren; Jen, Yi-Hsiu; Tsai, Hsieh-Hung; Chen, Wei-Jin

    2012-07-01

    A number of activated carbons derived from waste tires were further impregnated by gaseous elemental sulfur at temperatures of 400 and 650 degrees C, with a carbon and sulfur mass ratio of 1:3. The capabilities of sulfur diffusing into the micropores of the activated carbons were significantly different between 400 and 650 degrees C, resulting in obvious dissimilarities in the sulfur content of the activated carbons. The sulfur-impregnated activated carbons were examined for the adsorptive capacity of gas-phase mercuric chloride (HgC1) by thermogravimetric analysis (TGA). The analytical precision of TGA was up to 10(-6) g at the inlet HgCl2 concentrations of 100, 300, and 500 microg/m3, for an adsorption time of 3 hr and an adsorption temperature of 150 degrees C, simulating the flue gas emitted from municipal solid waste (MSW) incinerators. Experimental results showed that sulfur modification can slightly reduce the specific surface area of activated carbons. High-surface-area activated carbons after sulfur modification had abundant mesopores and micropores, whereas low-surface-area activated carbons had abundant macropores and mesopores. Sulfur molecules were evenly distributed on the surface of the inner pores after sulfur modification, and the sulfur content of the activated carbons increased from 2-2.5% to 5-11%. After sulfur modification, the adsorptive capacity of HgCl2 for high-surface-area sulfurized activated carbons reached 1.557 mg/g (22 times higher than the virgin activated carbons). The injection of activated carbons was followed by fabric filtration, which is commonly used to remove HgCl2 from MSW incinerators. The residence time of activated carbons collected in the fabric filter is commonly about 1 hr, but the time required to achieve equilibrium is less than 10 min. Consequently, it is worthwhile to compare the adsorption rates of HgCl2 in the time intervals of < 10 and 10-60 min.

  18. Distributive Education--Fashion Show. Kit No. 88. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Walters, Brenda B.

    An instructor's manual and student activity guide on fashion shows are provided in this set of prevocational education materials which focuses on the vocational area of distributive education. (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven vocational offerings: agriculture, home…

  19. 26 CFR 1.513-3 - Qualified convention and trade show activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... purpose of the sponsoring organization in conducting the show is the education of its members, or the promotion and stimulation of interest in, and demand for, the products or services of the industry (or... interest in, and demand for such products or services; (ii) Activities designed to educate persons in...

  20. 26 CFR 1.513-3 - Qualified convention and trade show activity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... purpose of the sponsoring organization in conducting the show is the education of its members, or the promotion and stimulation of interest in, and demand for, the products or services of the industry (or... interest in, and demand for such products or services; (ii) Activities designed to educate persons in...

  1. 26 CFR 1.513-3 - Qualified convention and trade show activity.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... purpose of the sponsoring organization in conducting the show is the education of its members, or the promotion and stimulation of interest in, and demand for, the products or services of the industry (or... interest in, and demand for such products or services; (ii) Activities designed to educate persons in...

  2. 26 CFR 1.513-3 - Qualified convention and trade show activity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... purpose of the sponsoring organization in conducting the show is the education of its members, or the promotion and stimulation of interest in, and demand for, the products or services of the industry (or... interest in, and demand for such products or services; (ii) Activities designed to educate persons in...

  3. 26 CFR 1.513-3 - Qualified convention and trade show activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... purpose of the sponsoring organization in conducting the show is the education of its members, or the promotion and stimulation of interest in, and demand for, the products or services of the industry (or... interest in, and demand for such products or services; (ii) Activities designed to educate persons in...

  4. Antibodies to meningococcal H.8 (Lip) antigen fail to show bactericidal activity.

    PubMed

    Bhattacharjee, A K; Moran, E E; Zollinger, W D

    1990-02-01

    Purified H.8 (Lip) antigen was coupled to tresyl-activated Sepharose 4B and used in affinity columns to purify anti-Lip antibodies from convalescent patient sera and from immune rabbit sera. Affinity-purified anti-Lip antibodies isolated from two convalescent patient sera contained 1000 and 1280 ELISA units of antibody and included antibodies of IgG, IgA, and IgM isotypes. An anti-Lip mouse monoclonal ascites (2-1-CA2) had 28,400 ELISA units of antibody. Bactericidal assays were performed using three different case strains of Neisseria meningitidis group B, namely 44/76, 8532, and 8047. Neither preparation of purified human anti-Lip antibodies had detectable bactericidal activity against strains 44/76 and 8532, but one of the two had a titer of 1:4 against strain 8047. Anti-Lip antibodies that were purified from immune rabbit serum and contained 1600 ELISA units of anti-Lip antibodies also failed to show detectable bactericidal activity. The rabbits were immunized with purified Lip antigen and showed specific antibody levels of 2000-2200 units by ELISA, but even the unfractionated sera had little or no bactericidal activity against the test strains. The high titer mouse monoclonal ascites had no bactericidal activity against the test strains. The poor bactericidal activity associated with monoclonal and polyclonal antibodies to the Lip antigen suggest that in spite of other attractive properties it may not be useful as a meningococcal vaccine.

  5. New Eugenol Glucoside-based Derivative Shows Fungistatic and Fungicidal Activity against Opportunistic Candida glabrata.

    PubMed

    de Souza, Thiago Belarmino; Brito, Keila Mercês de Oliveira; Silva, Naiara Chaves; Rocha, Raissa Prado; de Sousa, Grasiely Faria; Duarte, Lucienir Pains; Coelho, Luiz Felipe Leomil; Dias, Amanda Latércia Tranches; Veloso, Marcia Paranho; Carvalho, Diogo Teixeira; Dias, Danielle Ferreira

    2016-01-01

    A new series of glucosides modified in their saccharide units were synthesized, evaluated against Candida sp., and compared to prototype 1, an eugenol tetracetyl glucoside previously synthesized and shown to be active against Candida glabrata. Among the new glucosides, benzyl derivative 5 was the most promising, showing fungistatic activity at IC50 18.1 μm against Candida glabrata (threefold higher than fluconazole) and fungicidal activity with a low IC90 value of 36.2 μm. Moreover, the cytotoxic activity of compound 5 (CC50 : 580.9 μm), tested in peripheral blood mononuclear cells, suggests its potential as an agent to treat Candida glabrata infections, with a selectivity index of 32. The new eugenol glucoside 5 may be considered as a novel structural pattern in the development of new anti-Candida drugs.

  6. Physical and chemical properties of selected agricultural byproduct-based activated carbons and their ability to adsorb geosmin.

    PubMed

    Ng, Chilton; Losso, Jack N; Marshall, Wayne E; Rao, Ramu M

    2002-09-01

    The objectives of this study were to evaluate selected physical and chemical properties of agricultural byproduct-based activated carbons made from pecan shells and sugarcane bagasse, and compare those properties to a commercial coal-based activated carbon as well as to compare the adsorption efficiency of these carbons for geosmin. Comparison of the physical and chemical properties of pecan shell- and bagasse-based carbons to the commercial carbon, Calgon Filtrasorb 400, showed that pecan shell carbon, but not the bagasse carbon, compared favorably to Filtrasorb 400, especially in terms of surface area, bulk density, ash and attrition. A carbon dosage study done in a model system showed the amount of geosmin adsorbed to be greater for Filtrasorb 400 and the bagasse-based carbon at low carbon concentrations than for the pecan shell carbons, but geosmin adsorption was similar in all carbons at higher carbon dosages. Application of the Freundlich isotherm model to the adsorption data showed that carbons made by steam activation of pecan shells or sugarcane bagasse had geosmin adsorption characteristics most like those of the commercial carbon. In terms of physical, chemical and adsorptive properties, steam-activated pecan shell carbon most resembled the commercial carbon and has the potential to replace Filtrasorb 400 in applications involving removal of geosmin from aqueous environments.

  7. Investigation kinetics mechanisms of adsorption malachite green onto activated carbon.

    PubMed

    Onal, Y; Akmil-Başar, C; Sarici-Ozdemir, C

    2007-07-19

    Lignite was used to prepare activated carbon (T3K618) by chemical activation with KOH. Pore properties of the activated carbon such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by t-plot based on N2 adsorption isotherm. BET surface area of activated carbon is determined as 1000 m2/g. Adsorption capacity of malachite green (MG) onto T3K618 activated carbon was investigated in a batch system by considering the effects of various parameters like initial concentration (100, 150 and 200 mg/L) and temperature (25, 40 and 50 degrees C). The adsorption process was relatively fast and equilibrium was reached after about 20 min for 100, 150 mg/L at all adsorption temperature. Equilibrium time for 200 mg/L was determined as 20 min and 40 min at 298, 313 and 323 K, respectively. Simple mass and kinetic models were applied to the experimental data to examine the mechanisms of adsorption and potential rate controlling steps such as external mass transfer, intraparticle diffusion. Pseudo second-order model was found to explain the kinetics of MG adsorption most effectively. It was found that both mass transfer and pore diffusion are important in determining the adsorption rates. The intraparticle diffusion rate constant, external mass transfer coefficient, film and pore diffusion coefficient at various temperatures were evaluated. The activation energy (Ea) was determined as 48.56, 63.16, 67.93 kJ/mol for 100, 150, 200 mg/L, respectively. The Langmiur and Freundlich isotherm were used to describe the adsorption equilibrium studies at different temperatures. Langmiur isotherm shows better fit than Freundlich isotherm in the temperature range studied. The thermodynamic parameters, such as DeltaG degrees, DeltaS and DeltaH degrees were calculated. The thermodynamics of dyes-T3K618 system indicates endothermic process.

  8. Isolation of Lactic Acid Bacteria Showing Antioxidative and Probiotic Activities from Kimchi and Infant Feces.

    PubMed

    Ji, Keunho; Jang, Na Young; Kim, Young Tae

    2015-09-01

    The purpose of this study was to investigate lactic acid bacteria with antioxidative and probiotic activities isolated from Korean healthy infant feces and kimchi. Isolates A1, A2, S1, S2, and S3 were assigned to Lactobacillus sp. and isolates A3, A4, E1, E2, E3, and E4 were assigned to Leuconostoc sp. on the basis of their physiological properties and 16S ribosomal DNA sequence analysis. Most strains were confirmed as safe bioresources through nonhemolytic activities and non-production of harmful enzymes such as β-glucosidase, β- glucuronidase and tryptophanase. The 11 isolates showed different resistance to acid and bile acids. In addition, they exhibited antibacterial activity against foodborne bacteria, especially Bacillus cereus, Listeria monocytogenes, and Escherichia coli. Furthermore, all strains showed significantly high levels of hydrophobicity. The antioxidant effects of culture filtrates of the 11 strains included 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging capacity, 2.2'- azino-bis (2-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity, and superoxide dismutase activity. The results revealed that most of the culture filtrates have effective scavenging activity for DPPH and ABTS radicals. All strains appeared to have effective superoxide dismutase activity. In conclusion, the isolated strains A1, A3, S1, and S3 have significant probiotic activities applicable to the development of functional foods and health-related products. These strains might also contribute to preventing and controlling several diseases associated with oxidative stress, when used as probiotics.

  9. Hexavalent chromium adsorption on impregnated palm shell activated carbon with polyethyleneimine.

    PubMed

    Owlad, Mojdeh; Aroua, Mohamed Kheireddine; Wan Daud, Wan Mohd Ashri

    2010-07-01

    Removal of Cr(VI) ions from aqueous solution was investigated using modified palm shell activated carbon. Low Molecular Weight Polyethyleneimine (LMW PEI) was used for impregnation purpose. The maximum amount of LMW PEI adsorbed on activated carbon was determined to be approximately 228.2mg/g carbon. The adsorption experiments were carried out in a batch system using potassium dichromate K(2)Cr(2)O(7) as the source of Cr(VI) in the synthetic waste water and modified palm shell activated carbon as the adsorbent. The effects of pH, concentration of Cr(VI) and PEI loaded on activated carbon were studied. The adsorption data were found to fit well with the Freundlich isotherm model. This modified Palm shell activated carbon showed high adsorption capacity for chromium ions.

  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 PAGES

    Zhang, Pengfei; Zhang, Zhiyong; Chen, Jihua; ...

    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. Stratigraphic sections showing coal correlations within the lower coal zone of the Paleocene Fort Union Formation, Fillmore Ranch and Seaverson Reservoir quadrangles, Carbon County, Wyoming

    SciTech Connect

    Honey, J.G.; Hettinger, R.D.

    1989-01-01

    Stratigraphic sections showing coal correlations within the lower coal zone of the Paleocene Fort Union Formation, Fillmore Ranch and Seaverson Reservoir quadrangles, Carbon County, Wyoming are presented.

  13. Activated carbon and tungsten oxide supported on activated carbon catalysts for toluene catalytic combustion.

    PubMed

    Alvarez-Merino, M A; Ribeiro, M F; Silva, J M; Carrasco-Marín, F; Maldonado-Hódar, F J

    2004-09-01

    We have used activated carbon (AC) prepared from almond shells as a support for tungsten oxide to develop a series of WOx/AC catalysts for the catalytic combustion of toluene. We conducted the reaction between 300 and 350 degrees C, using a flow of 500 ppm of toluene in air and space velocity (GHSV) in the range 4000-7000 h(-1). Results show that AC used as a support is an appropriate material for removing toluene from dilute streams. By decreasing the GHSV and increasing the reaction temperature AC becomes a specific catalyst for the total toluene oxidation (SCO2 = 100%), but in less favorable conditions CO appears as reaction product and toluene-derivative compounds are retained inside the pores. WOx/AC catalysts are more selective to CO2 than AC due to the strong acidity of this oxide; this behavior improves with increased metal loading and reaction temperature and contact time. The catalytic performance depends on the nonstoichiometric tungsten oxide obtained during the pretreatment. In comparison with other supports the WOx/AC catalysts present, at low reaction temperatures, higher activity and selectivity than WO, supported on SiO2, TiO2, Al2O3, or Y zeolite. This is due to the hydrophobic character of the AC surface which prevents the adsorption of water produced from toluene combustion thus avoiding the deactivation of the active centers. However, the use of WOx/AC system is always restricted by its gasification temperature (around 400 degrees C), which limits the ability to increase the conversion values by increasing reaction temperatures.

  14. 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.

  15. Efficient control of odors and VOC emissions via activated carbon technology.

    PubMed

    Mohamed, Farhana; Kim, James; Huang, Ruey; Nu, Huong Ton; Lorenzo, Vlad

    2014-07-01

    This research study was undertaken to enhance the efficiency and economy of carbon scrubbers in controlling odors and volatile organic compounds (VOCs) at the wastewater collection and treatment facilities of the Bureau of Sanitation, City of Los Angeles. The butane activity and hydrogen sulfide breakthrough capacity of activated carbon were assessed. Air streams were measured for odorous gases and VOCs and removal efficiency (RE) determined. Carbon towers showed average to excellent removal of odorous compounds, VOCs, and siloxanes; whereas, wet scrubbers demonstrated good removal of odorous compounds but low to negative removal of VOCs. It was observed that the relative humidity and empty bed contact time are one of the most important operating parameters of carbon towers impacting the pollutant RE. Regular monitoring of activated carbon and VOCs has resulted in useful information on carbon change-out frequency, packing recommendations, and means to improve performance of carbon towers.

  16. Plant crude extracts could be the solution: extracts showing in vivo antitumorigenic activity.

    PubMed

    Amara, A A; El-Masry, M H; Bogdady, H H

    2008-04-01

    Screening active compounds from plants lead to discover new medicinal drugs which have efficient protection and treatment roles against various diseases including cancer. In our study, extracts from different plants represent seeds of: Gossypium barbadense, Ricinus communis, Sesamum indicum, Nigella sativa, Vinca rosea and Melia azedarah; fruits of: Xanthium occidental; flowers of: Atriplex nummularia; barks of: Cinnamomum zeylanicum; latex of: Ficus carica and rhizomes of: Curcuma longa and Zingiber officinale were tested in vivo using three subsequent bioassays: the BST (Brine Shrimp Toxicity bioassay), AWD (Agar well diffusion antimicrobial bioassay) and AtPDT (Agrobacterium tumefaciens Potato Disc Tumor bioassay). AWD technique omitted any extracts have antimicrobial activities while BST omitted any extract did not has physiological activity and determined the various LC(50) of each plant extract. For the first time, using a range of concentrations in the AtPDT modified protocol allowed the detection of tumor promotion caused by extract represented by A. nummularia. Using cluster analysis leads to classifying the different plant extracts activities to six groups regarding to their toxicity, antitumor activities and both of them. The extracts from edible plants represent 50% of the first and the second group which have the highest antitumor activities represented in F. caraica (group 1) and C. longa (group 2) as well as the non-edible plant extracts of Gossypium barbadense and Ricinus communis. A comparison study between the edible and herbaceous plants different extracts for their antitumor activities was performed. We recommended using the modified protocols used in this study for investigating more plants and using crude plant extracts which have antitumor activities in cancer treatment. Edible plants, which show in vivo antitumor activities, are recommended as save sources for antitumor compounds.

  17. Reuse performance of granular-activated carbon and activated carbon fiber in catalyzed peroxymonosulfate oxidation.

    PubMed

    Yang, Shiying; Li, Lei; Xiao, Tuo; Zhang, Jun; Shao, Xueting

    2017-03-01

    Recently, activated carbon was investigated as an efficient heterogeneous metal-free catalyst to directly activate peroxymonosulfate (PMS) for degradation of organic compounds. In this paper, the reuse performance and the possible deactivation reasons of granular-activated carbon (GAC) and activated carbon fiber (ACF) in PMS activation were investigated. As results indicated, the reusability of GAC, especially in the presence of high PMS dosage, was relatively superior to ACF in catalyzed PMS oxidation of Acid Orange 7 (AO7), which is much more easily adsorbed by ACF than by GAC. Pre-oxidation experiments were studied and it was demonstrated that PMS oxidation on ACF would retard ACF's deactivation to a big extent. After pre-adsorption with AO7, the catalytic ability of both GAC and ACF evidently diminished. However, when methanol was employed to extract the AO7-spent ACF, the catalytic ability could recover quite a bit. GAC and ACF could also effectively catalyze PMS to degrade Reactive Black 5 (RB5), which is very difficult to be adsorbed even by ACF, but both GAC and ACF have poor reuse performance for RB5 degradation. The original organic compounds or intermediate products adsorbed by GAC or ACF would be possibly responsible for the deactivation.

  18. Computational Chemistry Approach to Interpret the Crystal Violet Adsorption on Golbasi Lignite Activated Carbon

    NASA Astrophysics Data System (ADS)

    Depci, Tolga; Sarikaya, Musa; Prisbrey, Keith A.; Yucel, Aysegul

    2016-10-01

    In this paper, adsorption mechanism of Crystal Violet (CV) dye from the aqueous solution on the activated carbon prepared from Golbasi lignite was explained and interpreted by a computational chemistry approach and experimental studies. Molecular dynamic simulations and Ab initio frontier orbital analysis indicated relatively high energy and electron transfer processes during adsorption, and molecular dynamics simulations showed CV dye molecules moving around on the activated carbon surface after adsorption, facilitating penetration into cracks and pores. The experimental results supported to molecular dynamic simulation and showed that the monolayer coverage occurred on the activated carbon surface and each CV dye ion had equal sorption activation energy.

  19. Bovine chromaffin cells in culture show carboxylesterase activities sensitive to organophosphorus compounds.

    PubMed

    Sogorb, M A; Vilanova, E; Quintanar, J L; Viniegra, S

    1996-09-01

    Carboxylesterase activities are widely distributed in a great variety of tissues; however, the biological function of these enzymes remains unclear. Some organophosphorus compounds induce a neurodegenarative syndrome related to the covalent modification of a carboxylesterase known as neuropathy target esterase. We investigated the expression of neuropathy target esterase and related carboxylesterase in bovine chromaffin cells with the aim of developing a potential in vitro model for studying the cellular function of carboxylesterase enzymes and toxic effects of organophosphorus compounds. Total phenyl valerate esterase exhibited an activity of 1.27 +/- 0.19 mU/10(5) cells (SD, n = 15). From the phenyl valerate esterase paraoxon and mipafox inhibition curves the following activities have been determined: B-activity (resistant to 40 microM paraoxon), 1.05 +/- 0.08 mU/10(5) cells (n = 8); C-activity (resistant to 40 microM paraoxon plus 250 microM mipafox), 0.12 +/- 0.05 mU/10(5) cells (n = 8); and neuropathy target esterase, calculated by the difference between B- and C-activities, 0.93 +/- 0.08 mU/10(5) cells (n = 8). All of these activities increased linearly with the number of cells and time of incubation with the substrate. Most of the phenol product of the reaction was released and detected in the extracellular medium. None of the components of the reaction were shown to affect cell viability when assessed by trypan blue exclusion. The study shows that bovine chromaffin cells possess carboxylesterase activities and respond to inhibition by paraoxon and mipafox, thus facilitating the discrimination of neuropathy target esterase. In conclusion, bovine chromaffin cells are appropriate as an in vitro cell model for studying toxic effects of organophosphorus compounds.

  20. Antiparkinson drug--Mucuna pruriens shows antioxidant and metal chelating activity.

    PubMed

    Dhanasekaran, Muralikrishnan; Tharakan, Binu; Manyam, Bala V

    2008-01-01

    Parkinson's disease is a neurodegenerative disorder for which no neurorestorative therapeutic treatment is currently available. Oxidative stress plays an important role in the pathophysiology of Parkinson's disease. The ancient Indian medical system, Ayurveda, traditionally uses Mucuna pruriens to treat Parkinson's disease. In our earlier studies, Mucuna pruriens has been shown to possess antiparkinson and neuroprotective effects in animal models of Parkinson's disease. The antioxidant activity of Mucuna pruriens was demonstrated by its ability to scavenge DPPH radicals, ABTS radicals and reactive oxygen species. Mucuna pruriens significantly inhibited the oxidation of lipids and deoxyribose sugar. Mucuna pruriens exhibited divalent iron chelating activity and did not show any genotoxic/mutagenic effect on the plasmid DNA. These results suggest that the neuroprotective and neurorestorative effect of Mucuna pruriens may be related to its antioxidant activity independent of the symptomatic effect. In addition, the drug appears to be therapeutically safe in the treatment of patients with Parkinson's disease.

  1. Cytorhabdovirus phosphoprotein shows RNA silencing suppressor activity in plants, but not in insect cells.

    PubMed

    Mann, Krin S; Johnson, Karyn N; Dietzgen, Ralf G

    2015-02-01

    RNA silencing in plants and insects provides an antiviral defense and as a countermeasure most viruses encode RNA silencing suppressors (RSS). For the family Rhabdoviridae, no detailed functional RSS studies have been reported in plant hosts and insect vectors. In agroinfiltrated Nicotiana benthamiana leaves we show for the first time for a cytorhabdovirus, lettuce necrotic yellows virus (LNYV), that one of the nucleocapsid core proteins, phosphoprotein (P) has relatively weak local RSS activity and delays systemic silencing of a GFP reporter. Analysis of GFP small RNAs indicated that the P protein did not prevent siRNA accumulation. To explore RSS activity in insects, we used a Flock House virus replicon system in Drosophila S2 cells. In contrast to the plant host, LNYV P protein did not exhibit RSS activity in the insect cells. Taken together our results suggest that P protein may target plant-specific components of RNA silencing post siRNA biogenesis.

  2. Collagen-Immobilized Lipases Show Good Activity and Reusability for Butyl Butyrate Synthesis.

    PubMed

    Dewei, Song; Min, Chen; Haiming, Cheng

    2016-11-01

    Candida rugosa lipases were immobilized onto collagen fibers through glutaraldehyde cross-linking method. The immobilization process has been optimized. Under the optimal immobilization conditions, the activity of the collagen-immobilized lipase reached 340 U/g. The activity was recovered of 28.3 % by immobilization. The operational stability of the obtained collagen-immobilized lipase for hydrolysis of olive oil emulsion was determined. The collagen-immobilized lipase showed good tolerance to temperature and pH variations in comparison to free lipase. The collagen-immobilized lipase was also applied as biocatalyst for synthesis of butyl butyrate from butyric acid and 1-butanol in n-hexane. The conversion yield was 94 % at the optimal conditions. Of its initial activity, 64 % was retained after 5 cycles for synthesizing butyl butyrate in n-hexane.

  3. Functional characterization of a Plagiochasma appendiculatum flavone synthase I showing flavanone 2-hydroxylase activity.

    PubMed

    Han, Xiao-Juan; Wu, Yi-Feng; Gao, Shuai; Yu, Hai-Na; Xu, Rui-Xue; Lou, Hong-Xiang; Cheng, Ai-Xia

    2014-06-27

    FNS I is a 2-oxoglutarate dependent dioxygenase (2-ODD) found mainly in species of the Apiaceae family. Here, an FNS I cDNA sequence was isolated from the liverwort Plagiochasma appendiculatum (Aytoniaceae) and characterized. The recombinant protein exhibited high FNS I activity catalyzing the conversion of naringenin to apigenin and 2-hydroxynaringenin. The critical residue for flavanone-2-hydroxylation activity was Tyr240, as identified from homology modeling and site-directed mutagenesis. The recombinant protein also showed some flavonol synthase activity, as it can convert dihydrokaempferol to kaempferol. When the Leu311 residue was mutated to Phe, the enzyme's capacity to convert dihydrokaempferol to kaempferol was substantially increased. PaFNS I represents a 2-ODD in which a hydrophobic π-stacking interaction between the key residue and the naringenin A-ring determines 2-hydroxyflavanone formation.

  4. Task Control Signals in Pediatric Tourette Syndrome Show Evidence of Immature and Anomalous Functional Activity

    PubMed Central

    Church, Jessica A.; Wenger, Kristin K.; Dosenbach, Nico U. F.; Miezin, Francis M.; Petersen, Steven E.; Schlaggar, Bradley L.

    2009-01-01

    Tourette Syndrome (TS) is a pediatric movement disorder that may affect control signaling in the brain. Previous work has proposed a dual-networks architecture of control processing involving a task-maintenance network and an adaptive control network (Dosenbach et al., 2008). A prior resting-state functional connectivity MRI (rs-fcMRI) analysis in TS has revealed functional immaturity in both putative control networks, with “anomalous” correlations (i.e., correlations outside the typical developmental range) limited to the adaptive control network (Church et al., 2009). The present study used functional MRI (fMRI) to study brain activity related to adaptive control (by studying start-cues signals), and to task-maintenance (by studying signals sustained across a task set). Two hypotheses from the previous rs-fcMRI results were tested. First, adaptive control (i.e., start-cue) activity will be altered in TS, including activity inconsistent with typical development (“anomalous”). Second, group differences found in task-maintenance (i.e., sustained) activity will be consistent with functional immaturity in TS. We examined regions found through a direct comparison of adolescents with and without TS, as well as regions derived from a previous investigation that showed differences between unaffected children and adults. The TS group showed decreased start-cue signal magnitude in regions where start-cue activity is unchanged over typical development, consistent with anomalous adaptive control. The TS group also had higher magnitude sustained signals in frontal cortex regions that overlapped with regions showing differences over typical development, consistent with immature task-maintenance in TS. The results demonstrate task-related fMRI signal differences anticipated by the atypical functional connectivity found previously in adolescents with TS, strengthening the evidence for functional immaturity and anomalous signaling in control networks in adolescents with TS

  5. [Modification of activated carbon fiber for electro-Fenton degradation of phenol].

    PubMed

    Ma, Nan; Tian, Yao-Jin; Yang, Guang-Ping; Xie, Xin-Yuan

    2014-07-01

    Microwave-modified activated carbon fiber (ACF-1), nitric acid-modified activated carbon fiber (ACF-2), phosphoric acid-modified activated carbon fiber (ACF-3) and ammonia-modified activated carbon fiber (ACF-4) were successfully fabricated. The electro-Fenton catalytic activities of modified activated carbon fiber were evaluated using phenol as a model pollutant. H2O2 formation, COD removal efficiency and phenol removal efficiency were investigated compared with the unmodified activated carbon fiber (ACF-0). Results indicated that ACF-1 showed the best adsorption and electrocatalytic activity. Modification was in favor of the formation of H2O2. The performance of different systems on phenol degradation and COD removal were ACF-1 > ACF-3 > ACF-4 > ACF-2 > ACF-0 and ACF-1 > ACF-4 > ACF-3 > ACF-2 > ACF-0, respectively, which confirmed that electrocatalytic activities of modified activated carbon fiber were better than the unmodified. In addition, phenol intermediates were not the same while using different modified activated carbon fibers.

  6. Antibodies to Meningococcal H.8 (Lip) Antigen Fail to Show Bactericidal Activity

    DTIC Science & Technology

    1990-01-01

    monoclonaux n’avaient pas non plus d’activit6 bactericide contre ces souches. La faible activitt bactdricide associee aux anticorps monoclonaux et...MENINGOCOCCAL H.8 (Lip) ANTIGEN FAILTO SHOW BACTERICIDAL ACTIVITY. 12. PERSONAL. DUTHOR(S AK BHATTACHARJEE, EE MORAN, & WD ZOLLINGER. lb. TMP OP REPORT DATE...isotypes. An anti-Lip mouse monoclonal ascites (2-1-CA2) had 28 400 ELISA units of antibody. Bactericidal assays were performed using three different

  7. The three catalases in Deinococcus radiodurans: Only two show catalase activity.

    PubMed

    Jeong, Sun-Wook; Jung, Jong-Hyun; Kim, Min-Kyu; Seo, Ho Seong; Lim, Heon-Man; Lim, Sangyong

    2016-01-15

    Deinococcus radiodurans, which is extremely resistant to ionizing radiation and oxidative stress, is known to have three catalases (DR1998, DRA0146, and DRA0259). In this study, to investigate the role of each catalase, we constructed catalase mutants (Δdr1998, ΔdrA0146, and ΔdrA0259) of D. radiodurans. Of the three mutants, Δdr1998 exhibited the greatest decrease in hydrogen peroxide (H2O2) resistance and the highest increase in intracellular reactive oxygen species (ROS) levels following H2O2 treatments, whereas ΔdrA0146 showed no change in its H2O2 resistance or ROS level. Catalase activity was not attenuated in ΔdrA0146, and none of the three bands detected in an in-gel catalase activity assay disappeared in ΔdrA0146. The purified His-tagged recombinant DRA0146 did not show catalase activity. In addition, the phylogenetic analysis of the deinococcal catalases revealed that the DR1998-type catalase is common in the genus Deinococcus, but the DRA0146-type catalase was found in only 4 of 23 Deinococcus species. Taken together, these results indicate that DR1998 plays a critical role in the anti-oxidative system of D. radiodurans by detoxifying H2O2, but DRA0146 does not have catalase activity and is not involved in the resistance to H2O2 stress.

  8. Water-soluble extracts from defatted sesame seed flour show antioxidant activity in vitro.

    PubMed

    Ben Othman, Sana; Katsuno, Nakako; Kanamaru, Yoshihiro; Yabe, Tomio

    2015-05-15

    Defatted white and gold sesame seed flour, recovered as a byproduct after sesame oil extraction, was extracted with 70% ethanol to obtain polar-soluble crude extracts. The in vitro antioxidant activity of the extract was evaluated by DPPH free radical scavenging activity and oxygen radical absorbing capacity (ORAC). The polar-soluble crude extracts of both sesame seed types exhibited good antioxidant capacity, especially by the ORAC method with 34,720 and 21,700 μmol Trolox equivalent/100g of white and gold sesame seed extract, respectively. HPLC, butanol extraction, and UPLC-MS analyses showed that different compounds contributed to the antioxidant activity of the polar-soluble crude extracts. Sesaminol glycosides were identified in the butanol-soluble fractions; whereas, purified water-soluble fraction contained ferulic and vanillic acids. This study shows that hydrophilic antioxidants in the purified water-soluble fraction contributed to the antioxidant activity of white and gold sesame seed polar-soluble crude extracts.

  9. Sterols from Mytilidae show anti-aging and neuroprotective effects via anti-oxidative activity.

    PubMed

    Sun, Yujuan; Lin, Yanfei; Cao, Xueli; Xiang, Lan; Qi, Jianhua

    2014-11-25

    For screening anti-aging samples from marine natural products, K6001 yeast strain was employed as a bioassay system. The active mussel extract was separated to give an active sterol fraction (SF). SF was further purified, and four sterol compounds were obtained. Their structures were determined to be cholesterol (CHOL), brassicasterol, crinosterol, and 24-methylenecholesterol. All compounds showed similar anti-aging activity. To understand the action mechanism involved, anti-oxidative experiments, reactive oxygen species (ROS) assays, and malondialdehyde (MDA) tests were performed on the most abundant compound, CHOL. Results indicated that treatment with CHOL increases the survival rate of yeast under oxidative stress and decreases ROS and MDA levels. In addition, mutations of uth1, skn7, sod1, and sod2, which feature a K6001 background, were employed and the lifespans of the mutations were not affected by CHOL. These results demonstrate that CHOL exerts anti-aging effects via anti-oxidative stress. Based on the connection between neuroprotection and anti-aging, neuroprotective experiments were performed in PC12 cells. Paraquat was used to induce oxidative stress and the results showed that the CHOL and SF protect the PC12 cells from the injury induced by paraquat. In addition, these substance exhibited nerve growth factor (NGF) mimic activities again confirmed their neuroprotective function.

  10. Bovine serum albumin with glycated carboxyl groups shows membrane-perturbing activities.

    PubMed

    Yang, Shin-Yi; Chen, Ying-Jung; Kao, Pei-Hsiu; Chang, Long-Sen

    2014-12-15

    The aim of the present study aimed to investigate whether glycated bovine serum albumin (BSA) showed novel activities on the lipid-water interface. Mannosylated BSA (Man-BSA) was prepared by modification of the carboxyl groups with p-aminophenyl α-d-mannopyranoside. In contrast to BSA, Man-BSA notably induced membrane permeability of egg yolk phosphatidylcholine (EYPC)/egg yolk sphingomyelin (EYSM)/cholesterol (Chol) and EYPC/EYSM vesicles. Noticeably, Man-BSA induced the fusion of EYPC/EYSM/Chol vesicles, but not of EYPC/EYSM vesicles. Although BSA and Man-BSA showed similar binding affinity for lipid vesicles, the lipid-bound conformation of Man-BSA was distinct from that of BSA. Moreover, Man-BSA adopted distinct structure upon binding with the EYPC/EYSM/Chol and EYPC/EYSM vesicles. Man-BSA could induce the fusion of EYPC/EYSM/Chol vesicles with K562 and MCF-7 cells, while Man-BSA greatly induced the leakage of Chol-depleted K562 and MCF-7 cells. The modified BSA prepared by conjugating carboxyl groups with p-aminophenyl α-d-glucopyranoside also showed membrane-perturbing activities. Collectively, our data indicate that conjugation of carboxyl groups with monosaccharide generates functional BSA with membrane-perturbing activities on the lipid-water interface.

  11. Vv-AMP1, a ripening induced peptide from Vitis vinifera shows strong antifungal activity

    PubMed Central

    de Beer, Abré; Vivier, Melané A

    2008-01-01

    Background Latest research shows that small antimicrobial peptides play a role in the innate defense system of plants. These peptides typically contribute to preformed defense by developing protective barriers around germinating seeds or between different tissue layers within plant organs. The encoding genes could also be upregulated by abiotic and biotic stimuli during active defense processes. The peptides display a broad spectrum of antimicrobial activities. Their potent anti-pathogenic characteristics have ensured that they are promising targets in the medical and agricultural biotechnology sectors. Results A berry specific cDNA sequence designated Vv-AMP1, Vitis vinifera antimicrobial peptide 1, was isolated from Vitis vinifera. Vv-AMP1 encodes for a 77 amino acid peptide that shows sequence homology to the family of plant defensins. Vv-AMP1 is expressed in a tissue specific, developmentally regulated manner, being only expressed in berry tissue at the onset of berry ripening and onwards. Treatment of leaf and berry tissue with biotic or abiotic factors did not lead to increased expression of Vv-AMP1 under the conditions tested. The predicted signal peptide of Vv-AMP1, fused to the green fluorescent protein (GFP), showed that the signal peptide allowed accumulation of its product in the apoplast. Vv-AMP1 peptide, produced in Escherichia coli, had a molecular mass of 5.495 kDa as determined by mass spectrometry. Recombinant Vv-AMP1 was extremely heat-stable and showed strong antifungal activity against a broad spectrum of plant pathogenic fungi, with very high levels of activity against the wilting disease causing pathogens Fusarium oxysporum and Verticillium dahliae. The Vv-AMP1 peptide did not induce morphological changes on the treated fungal hyphae, but instead strongly inhibited hyphal elongation. A propidium iodide uptake assay suggested that the inhibitory activity of Vv-AMP1 might be associated with altering the membrane permeability of the fungal

  12. Subunits of the Snf1 kinase heterotrimer show interdependence for association and activity.

    PubMed

    Elbing, Karin; Rubenstein, Eric M; McCartney, Rhonda R; Schmidt, Martin C

    2006-09-08

    The Snf1 kinase and its mammalian orthologue, the AMP-activated protein kinase (AMPK), function as heterotrimers composed of a catalytic alpha-subunit and two non-catalytic subunits, beta and gamma. The beta-subunit is thought to hold the complex together and control subcellular localization whereas the gamma-subunit plays a regulatory role by binding to and blocking the function of an auto-inhibitory domain (AID) present in the alpha-subunit. In addition, catalytic activity requires phosphorylation by a distinct upstream kinase. In yeast, any one of three Snf1-activating kinases, Sak1, Tos3, or Elm1, can fulfill this role. We have previously shown that Sak1 is the only Snf1-activating kinase that forms a stable complex with Snf1. Here we show that the formation of the Sak1.Snf1 complex requires the beta- and gamma-subunits in vivo. However, formation of the Sak1.Snf1 complex is not necessary for glucose-regulated phosphorylation of the Snf1 activation loop. Snf1 kinase purified from cells lacking the beta-subunits do not contain any gamma-subunit, indicating that the Snf1 kinase does not form a stable alphagamma dimer in vivo. In vitro kinase assays using purified full-length and truncated Snf1 proteins demonstrate that the kinase domain, which lacks the AID, is significantly more active than the full-length Snf1 protein. Addition of purified beta- and gamma-subunits could stimulate the kinase activity of the full-length alpha-subunit but only when all three subunits were present, suggesting an interdependence of all three subunits for assembly of a functional complex.

  13. Negatively charged liposomes show potent adjuvant activity when simply admixed with protein antigens

    PubMed Central

    Yanasarn, Nijaporn; Sloat, Brian R.; Cui, Zhengrong

    2011-01-01

    Liposomes have been investigated extensively as a vaccine delivery system. Herein the adjuvant activities of liposomes with different net surface charges (neutral, positive, or negative) were evaluated when admixed with protein antigens, ovalbumin (OVA, pI = 4.7), Bacillus anthracis protective antigen protein (PA, pI = 5.6), or cationized OVA (cOVA). Mice immunized subcutaneously with OVA admixed with different liposomes generated different antibody responses. Interestingly, OVA admixed with net negatively charged liposomes prepared with DOPA was as immunogenic as OVA admixed with positively charged liposomes prepared with DOTAP. Immunization of mice with the anthrax PA protein admixed with the net negatively charged DOPA liposomes also induced a strong and functional anti-PA antibody response. When the cationized OVA was used as a model antigen, liposomes with net neutral, negative, or positive charges showed comparable adjuvant activities. Immunization of mice with the OVA admixed with DOPA liposomes also induced OVA-specific CD8+ cytotoxic T lymphocyte responses and significantly delayed the growth of OVA-expressing B16-OVA tumors in mice. However, not all net negatively charged liposomes showed a strong adjuvant activity. The adjuvant activity of the negatively charged liposomes may be related to the liposome’s ability (i) to up-regulate the expression of molecules related to the activation and maturation of antigen-presenting cells and (ii) to slightly facilitate the uptake of the antigens by antigen-presenting cells. Simply admixing certain negatively charged liposomes with certain protein antigens of interest may represent a novel platform for vaccine development. PMID:21615153

  14. A novel cathelicidin from Bufo bufo gargarizans Cantor showed specific activity to its habitat bacteria.

    PubMed

    Sun, Tongyi; Zhan, Bo; Gao, Yuanyuan

    2015-10-25

    Toad Bufo bufo gargarizans Cantor is still used in China as traditional Chinese medicine. However, present investigations on its skin secretions were mainly focused on the bufadienolides, the proteins/peptides contained in the secretions are largely unknown. A cDNA encoding a novel cathelicidin termed BG-CATH was identified by analysis of the toad skin transcriptome. The BG-CATH precursor was predicted to have 2 possible cleavage sites following dibasic cleavage signals at its C-terminal, which will generate two mature peptides, BG-CATH37 and BG-CATH(5-37). Phylogenetic analysis suggests that amphibian cathelicidins might evolve from common ancestors. The two predicted mature cathelicidins from B. bufo gargarizans were synthesized and both of them showed weak antimicrobial activities against human pathogenic bacteria Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus (MIC ≥ 200 μg/mL). However, BG-CATH37 and BG-CATH(5-37) had strong antimicrobial activities against aquatic bacteria of Vibrio splendidus, Streptococcus iniae and Aeromorus hydrophila, which were common microorganisms in the habitat of B. bufo gargarizans (MIC 3.125-40 μg/mL). BG-CATH37 and BG-CATH(5-37) showed no hemolytic activity even at high concentrations (400 μg/mL). CD spectra analysis suggested that structure rigidity of BG-CATH37 and BG-CATH(5-37) might play an important role to regulate their biological activities. Selective antimicrobial activity against habitat microorganisms might reflect the adaptation of amphibians to their living environments.

  15. [Adsorption of perfluorooctanesulfonate (PFOS) onto modified activated carbons].

    PubMed

    Tong, Xi-Zhen; Shi, Bao-You; Xie, Yue; Wang, Dong-Sheng

    2012-09-01

    Modified coal and coconut shell based powdered activated carbons (PACs) were prepared by FeCl3 and medium power microwave treatment, respectively. Batch experiments were carried out to evaluate the characteristics of adsorption equilibrium and kinetics of perfluorooctanesulfonate (PFOS) onto original and modified PACs. Based on pore structure and surface functional groups characterization, the adsorption behaviors of modified and original PACs were compared. The competitive adsorption of humic acid (HA) and PFOS on original and modified coconut shell PACs were also investigated. Results showed that both Fe3+ and medium power microwave treatments changed the pore structure and surface functional groups of coal and coconut shell PACs, but the changing effects were different. The adsorption of PFOS on two modified coconut shell-based PACs was significantly improved. While the adsorption of modified coal-based activated carbons declined. The adsorption kinetics of PFOS onto original and modified coconut shell-based activated carbons were the same, and the time of reaching adsorption equilibrium was about 6 hours. In the presence of HA, the adsorption of PFOS by modified PAC was reduced but still higher than that of the original.

  16. Adsorption onto fluidized powdered activated carbon flocs-pACF.

    PubMed

    Serpa, Ana Lídia; Schneider, Ivo André H; Rubio, Jorge

    2005-02-01

    This work presents a new adsorption technique where the adsorbent (powdered activated carbon-PAC) is in the form of suspended flocs formed with water-soluble polymer flocculants. Thus, the adsorption of a typical dye, methylene blue (MB), was studied onto polyacrylamide flocs of PAC (PACF) in a fluidized bed reactor. The technique is based on the fact that the adsorption capacity of PAC does not decrease after flocculation because the adsorbed polymer occupies only a few surface sites, in the form of trains, loops, and tails. Moreover, the adsorption was found to proceed through a rapid mass transfer of MB to the adsorbing PAC flocs, in the same extent as onto PAC. Because of the rapid settling characteristics of the aggregates formed, the two phase separations, loaded PAC and solution, become easier. Thus, the technique offers the advantages of conducting simultaneously both adsorption and solid/liquid separation all in one single stage. Results obtained showed that high MB removal values can be attained in a fluidized bed reactor (>90%) and that PACF presents a much higher adsorption capacity (breakthrough points) than granulated activated carbon (GAC) in the same adsorbing bed. It is believed that this technique highly broadens the potential of the use of powdered activated carbon or other similar ultrafine adsorbents.

  17. Preparation of steam activated carbon from rubberwood sawdust (Hevea brasiliensis) and its adsorption kinetics.

    PubMed

    Prakash Kumar, B G; Shivakamy, K; Miranda, Lima Rose; Velan, M

    2006-08-25

    Activated carbon was produced from a biowaste product, rubberwood sawdust (RWSD) using steam in a high temperature fluidized bed reactor. Experiments were carried out to investigate the influence of various process parameters such as activation time, activation temperature, particle size and fluidising velocity on the quality of the activated carbon. The activated carbon was characterized based on its iodine number, methylene blue number, Brauner Emmet Teller (BET) surface area and surface area obtained using the ethylene glycol mono ethyl ether (EGME) retention method. The best quality activated carbon was obtained at an activation time and temperature of 1h and 750 degrees C for an average particle size of 0.46 mm. The adsorption kinetics shows that pseudo-second-order rate fitted the adsorption kinetics better than pseudo-first-order rate equation. The adsorption capacity of carbon produced from RWSD was found to be 1250 mg g(-1) for the Bismark Brown dye. The rate constant and diffusion coefficient for intraparticle transport were determined for steam activated carbon. The characteristic of the prepared activated carbon was found comparable to the commercial activated carbon.

  18. Process effects on activated carbon with large specific surface area from corn cob.

    PubMed

    Cao, Qing; Xie, Ke-Chang; Lv, Yong-Kang; Bao, Wei-Ren

    2006-01-01

    The main factors that affect the large specific surface area (SSA) of the activated carbon from agricultural waste corn cobs were studied by chemically activated method with solution of KOH and soap which acted as surfactant. The experiment showed that not only the activation temperature, activation time and the mass ratio of KOH to the carbonized material, but also the activated methods using activator obviously influenced the SSA of activated carbon. The experimental operating conditions were as follows: the carbonized temperature being 450 degrees C and keeping time being 4 h using N2 as protective gas; the activation temperature being 850 degrees C and holding time being 1.2 h; the mass ratio of KOH to carbonized material being 4.0; the time of soaking carbonized material in the solution of KOH and soap being 30 min. Under the optimal conditions, the SSA of activated carbon from corn cobs reached 2700 m2/g. And the addition of the soap as surfactant may shorten the soaking time. The structure of the activated carbon prepared had narrow distribution of pore size and the micro-pores accounted for 78%. The advantages of the method described were easy and feasible.

  19. Newly derived GH43 gene from compost metagenome showing dual xylanase and cellulase activities.

    PubMed

    Sae-Lee, Ritthironk; Boonmee, Atcha

    2014-09-01

    A metagenomic fosmid library was constructed from compost microbial communities that were collected from various farms throughout the Khon Kaen province, Thailand. The library was enriched in carboxymethylcellulose (CM-cellulose)--containing media prior to the screening of clones capable of degrading cellulosic materials. Two clones were selected for further subcloning and sequencing based on different patterns from restriction analysis. Deduced amino acid analysis of possible ORFs revealed one novel gene encoding an enzyme belonging to glycosyl hydrolase family 43 (GH43), which is a GH family rarely found in metagenomic studies. The most notable finding is that this enzyme, designated as Biof1_09, shows dual activities, namely endocellulase and endoxylanase activities. Biof1_09 showed greater than 50% of its activity under acidic conditions ranging from pH 3.5 to 5.5 with a pH optimum of 4.5. The optimum temperature of this enzyme was between 45 and 55 °C with an optimum of 50 °C. The properties of Biof1_09 make this enzyme an attractive candidate for large-scale expression for use in lignocellulose degradation for various bioprocess applications, including bioethanol fermentation.

  20. Brain potentials show rapid activation of implicit attitudes towards young and old people.

    PubMed

    van der Lugt, Arie H; Banfield, Jane F; Osinsky, Roman; Münte, Thomas F

    2012-01-06

    While previous behavioural research suggests that attitudes, for example towards elderly people, may be activated automatically, this type of research does not provide information about the detailed time-course of such processing in the brain. We investigated the impact of age related attitude information in a Go/NoGo association task that paired photographs of elderly or young faces with positive or negative words. Event related brain potentials showed an N200 (NoGo) component, which appeared earlier in runs which required similar responses for congruent stimulus pairings (e.g. respond to pictures of elderly faces or negative words) than for incongruent pairings (e.g. respond to elderly faces or positive words). As information processing leading to a certain attitude must precede differential brain activity according to the congruence of the paired words and faces, we show that this type of information is activated almost immediately following the structural encoding of the face, between 170 and 230 ms after onset of the face.

  1. Variegation of comet 67P/Churyumov-Gerasimenko in regions showing activity

    NASA Astrophysics Data System (ADS)

    Oklay, N.; Vincent, J.-B.; Fornasier, S.; Pajola, M.; Besse, S.; Davidsson, B. J. R.; Lara, L. M.; Mottola, S.; Naletto, G.; Sierks, H.; Barucci, A. M.; Scholten, F.; Preusker, F.; Pommerol, A.; Masoumzadeh, N.; Lazzarin, M.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; A'Hearn, M. F.; Bertaux, J.-L.; Bertini, I.; Bodewits, D.; Cremonese, G.; Da Deppo, V.; Debei, S.; De Cecco, M.; Fulle, M.; Groussin, O.; Gutiérrez, P. J.; Güttler, C.; Hall, I.; Hofmann, M.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Keller, H. U.; Knollenberg, J.; Kovacs, G.; Kramm, J.-R.; Kührt, E.; Küppers, M.; Lin, Z.-Y.; Lopez Moreno, J. J.; Marzari, F.; Moreno, F.; Shi, X.; Thomas, N.; Toth, I.; Tubiana, C.

    2016-02-01

    Aims.We carried out an investigation of the surface variegation of comet 67P/Churyumov-Gerasimenko, the detection of regions showing activity, the determination of active and inactive surface regions of the comet with spectral methods, and the detection of fallback material. Methods: We analyzed multispectral data generated with Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) narrow angle camera (NAC) observations via spectral techniques, reflectance ratios, and spectral slopes in order to study active regions. We applied clustering analysis to the results of the reflectance ratios, and introduced the new technique of activity thresholds to detect areas potentially enriched in volatiles. Results: Local color inhomogeneities are detected over the investigated surface regions. Active regions, such as Hapi, the active pits of Seth and Ma'at, the clustered and isolated bright features in Imhotep, the alcoves in Seth and Ma'at, and the large alcove in Anuket, have bluer spectra than the overall surface. The spectra generated with OSIRIS NAC observations are dominated by cometary emissions of around 700 nm to 750 nm as a result of the coma between the comet's surface and the camera. One of the two isolated bright features in the Imhotep region displays an absorption band of around 700 nm, which probably indicates the existence of hydrated silicates. An absorption band with a center between 800-900 nm is tentatively observed in some regions of the nucleus surface. This absorption band can be explained by the crystal field absorption of Fe2+, which is a common spectral feature seen in silicates.

  2. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    PubMed

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

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

    PubMed

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

    2009-03-01

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

  4. Two chitinase-like proteins abundantly accumulated in latex of mulberry show insecticidal activity

    PubMed Central

    2010-01-01

    Background Plant latex is the cytoplasm of highly specialized cells known as laticifers, and is thought to have a critical role in defense against herbivorous insects. Proteins abundantly accumulated in latex might therefore be involved in the defense system. Results We purified latex abundant protein a and b (LA-a and LA-b) from mulberry (Morus sp.) and analyzed their properties. LA-a and LA-b have molecular masses of approximately 50 and 46 kDa, respectively, and are abundant in the soluble fraction of latex. Western blotting analysis suggested that they share sequence similarity with each other. The sequences of LA-a and LA-b, as determined by Edman degradation, showed chitin-binding domains of plant chitinases at the N termini. These proteins showed small but significant chitinase and chitosanase activities. Lectin RCA120 indicated that, unlike common plant chitinases, LA-a and LA-b are glycosylated. LA-a and LA-b showed insecticidal activities when fed to larvae of the model insect Drosophila melanogaster. Conclusions Our results suggest that the two LA proteins have a crucial role in defense against herbivorous insects, possibly by hydrolyzing their chitin. PMID:20109180

  5. Children who stutter show reduced action-related activity in the rostral cingulate zone.

    PubMed

    Harrewijn, A; Schel, M A; Boelens, H; Nater, C M; Haggard, P; Crone, E A

    2017-02-01

    Previous studies have indicated that children who stutter show not only speech-related problems, but also wider difficulties in self-control. In this study we test the novel hypothesis that children who stutter may experience difficulties with inhibitory control over voluntary actions. We used functional MRI to compare brain activity between children who stutter and children who do not stutter in a task that captures key cognitive aspects of voluntary action control. Participants performed a rolling marble task, in which they were instructed to press a key to stop a rolling marble from crashing on some of the trials (instructed action condition). They were also asked to choose voluntarily whether to execute or inhibit this prepotent response in other trials (volition condition). Children who stutter reported less motor and cognitive impulsivity and had shorter stop-signal reaction times when controlled for IQ, consistent with greater inhibition, compared to children who do not stutter. At the neural level, children who stutter showed decreased activation in the rostral cingulate zone during voluntary action selection compared to children who do not stutter. This effect was more pronounced for children who were rated as showing more stuttered syllables in the stutter screening, and was furthermore correlated with stop-signal reaction times and impulsivity ratings. These findings suggest that stuttering in childhood could reflect wider difficulties in self-control, also in the non-verbal domain. Understanding these neural mechanisms could potentially lead to more focused treatments of stuttering.

  6. Eddy covariance and biometric measurements show that a savanna ecosystem in Southwest China is a carbon sink

    PubMed Central

    Fei, Xuehai; Jin, Yanqiang; Zhang, Yiping; Sha, Liqing; Liu, Yuntong; Song, Qinghai; Zhou, Wenjun; Liang, Naishen; Yu, Guirui; Zhang, Leiming; Zhou, Ruiwu; Li, Jing; Zhang, Shubin; Li, Peiguang

    2017-01-01

    Savanna ecosystems play a crucial role in the global carbon cycle. However, there is a gap in our understanding of carbon fluxes in the savanna ecosystems of Southeast Asia. In this study, the eddy covariance technique (EC) and the biometric-based method (BM) were used to determine carbon exchange in a savanna ecosystem in Southwest China. The BM-based net ecosystem production (NEP) was 0.96 tC ha−1 yr−1. The EC-based estimates of the average annual gross primary productivity (GPP), ecosystem respiration (Reco), and net ecosystem carbon exchange (NEE) were 6.84, 5.54, and −1.30 tC ha−1 yr−1, respectively, from May 2013 to December 2015, indicating that this savanna ecosystem acted as an appreciable carbon sink. The ecosystem was more efficient during the wet season than the dry season, so that it represented a small carbon sink of 0.16 tC ha−1 yr−1 in the dry season and a considerable carbon sink of 1.14 tC ha−1 yr−1 in the wet season. However, it is noteworthy that the carbon sink capacity may decline in the future under rising temperatures and decreasing rainfall. Consequently, further studies should assess how environmental factors and climate change will influence carbon-water fluxes. PMID:28145459

  7. Eddy covariance and biometric measurements show that a savanna ecosystem in Southwest China is a carbon sink

    NASA Astrophysics Data System (ADS)

    Fei, Xuehai; Jin, Yanqiang; Zhang, Yiping; Sha, Liqing; Liu, Yuntong; Song, Qinghai; Zhou, Wenjun; Liang, Naishen; Yu, Guirui; Zhang, Leiming; Zhou, Ruiwu; Li, Jing; Zhang, Shubin; Li, Peiguang

    2017-02-01

    Savanna ecosystems play a crucial role in the global carbon cycle. However, there is a gap in our understanding of carbon fluxes in the savanna ecosystems of Southeast Asia. In this study, the eddy covariance technique (EC) and the biometric-based method (BM) were used to determine carbon exchange in a savanna ecosystem in Southwest China. The BM-based net ecosystem production (NEP) was 0.96 tC ha‑1 yr‑1. The EC-based estimates of the average annual gross primary productivity (GPP), ecosystem respiration (Reco), and net ecosystem carbon exchange (NEE) were 6.84, 5.54, and ‑1.30 tC ha‑1 yr‑1, respectively, from May 2013 to December 2015, indicating that this savanna ecosystem acted as an appreciable carbon sink. The ecosystem was more efficient during the wet season than the dry season, so that it represented a small carbon sink of 0.16 tC ha‑1 yr‑1 in the dry season and a considerable carbon sink of 1.14 tC ha‑1 yr‑1 in the wet season. However, it is noteworthy that the carbon sink capacity may decline in the future under rising temperatures and decreasing rainfall. Consequently, further studies should assess how environmental factors and climate change will influence carbon-water fluxes.

  8. Two Analogues of Fenarimol Show Curative Activity in an Experimental Model of Chagas Disease

    PubMed Central

    2013-01-01

    Chagas disease, caused by the protozoan parasite Trypanosoma cruzi (T. cruzi), is an increasing threat to global health. Available medicines were introduced over 40 years ago, have undesirable side effects, and give equivocal results of cure in the chronic stage of the disease. We report the development of two compounds, 6 and (S)-7, with PCR-confirmed curative activity in a mouse model of established T. cruzi infection after once daily oral dosing for 20 days at 20 mg/kg 6 and 10 mg/kg (S)-7. Compounds 6 and (S)-7 have potent in vitro activity, are noncytotoxic, show no adverse effects in vivo following repeat dosing, are prepared by a short synthetic route, and have druglike properties suitable for preclinical development. PMID:24304150

  9. Effects of microwave heating on porous structure of regenerated powdered activated carbon used in xylose.

    PubMed

    Li, Wei; Wang, Xinying; Peng, Jinhui

    2014-01-01

    The regeneration of spent powdered activated carbons used in xylose decolourization by microwave heating was investigated. Effects of microwave power and microwave heating time on the adsorption capacity of regenerated activated carbons were evaluated. The optimum conditions obtained are as follows: microwave power 800W; microwave heating time 30min. Regenerated activated carbon in this work has high adsorption capacities for the amount of methylene blue of 16 cm3/0.1 g and the iodine number of 1000.06mg/g. The specific surface areas of fresh commercial activated carbon, spent carbon and regenerated activated carbon were calculated according to the Brunauer, Emmett and Teller method, and the pore-size distributions of these carbons were characterized by non-local density functional theory (NLDFT). The results show that the specific surface area and the total pore volume of regenerated activated carbon are 1064 m2/g and 1.181 mL/g, respectively, indicating the feasibility of regeneration of spent powdered activated carbon used in xylose decolourization by microwave heating. The results of surface fractal dimensions also confirm the results of isotherms and NLDFT.

  10. Endolymphatic Sac Tumor Showing Increased Activity on 68Ga DOTATATE PET/CT.

    PubMed

    Papadakis, Georgios Z; Millo, Corina; Sadowski, Samira M; Bagci, Ulas; Patronas, Nicholas J

    2016-10-01

    Endolymphatic sac tumors (ELSTs) are rare tumors arising from the epithelium of the endolymphatic sac and duct that can be either sporadic or associated with von Hippel-Lindau (VHL) disease. We report a case of a VHL patient with histologically proven residual ELST who underwent Ga DOTATATE PET/CT showing increased activity (SUVmax, 6.29) by the ELST. The presented case of a VHL-associated ELST with increased Ga DOTATATE uptake indicates cell-surface expression of somatostatin receptors by this tumor, suggesting the potential application of somatostatin receptor imaging using Ga DOTA-conjugated peptides in the workup and management of these patients.

  11. Characterization of activated carbon prepared from chlorella-based algal residue.

    PubMed

    Chang, Yuan-Ming; Tsai, Wen-Tien; Li, Ming-Hsuan

    2015-05-01

    The chlorella-based microalgal residue (AR) was tested as a novel precursor for preparing activated carbons. A combined carbonization-activation process with flowing N2 and CO2 gases was used to prepare the carbon materials at the activation temperatures of 800-1000 °C and the residence times of 0-30 min in this work. The elemental contents, pore properties and scanning electron microscopy (SEM) observations of the resulting activated carbons have been performed. The results showed that activation temperature may be the most important parameter for determining their pore properties. The maximal Brunauer-Emmett-Teller (BET) surface area and total pore volume of the resulting activated carbon, which was produced at the activation temperature of 950 °C with the residence time of 30 min, were 840 m(2)/g and 0.46 cm(3)/g, respectively. More interestingly, the resulting activated carbons have significant nitrogen contents of 3.6-9.6 wt%, which make them lower carbon contents (i.e., 54.6-68.4 wt%) than those of commercial activated carbons.

  12. 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.

  13. Removal of color from biomethanated distillery spentwash by treatment with activated carbons.

    PubMed

    Satyawali, Y; Balakrishnan, M

    2007-10-01

    This work examined 19 carbon samples prepared by acid and thermal activation of various agro-residues viz. bagasse, bagasse flyash, sawdust, wood ash and rice husk ash for color removal from biomethanated distillery effluent. Phosphoric acid carbonized bagasse B (PH) showed the maximum color removal (50%). However, commercial activated carbons AC (ME) and AC (LB) showed better performance of over 80% color removal. Besides color removal, activated carbon treatment also showed reduction in chemical oxygen demand (COD), total organic carbon (TOC), phenol and total Kjeldahl nitrogen (TKN). The performance was related to the characteristics of the investigated samples. Further, adsorption isotherms for melanoidins, which is the primary coloring compound in distillery spentwash, followed the Langmuir isotherm implying monolayer adsorption.

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

    PubMed

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

    2017-06-01

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

  15. Activation of carbon dioxide on metal and metal oxide surfaces

    SciTech Connect

    Tan, C.D.; Chuang, S.S.C.

    1995-12-31

    The environmental concern about the impact of CO{sub 2} has grown recently due to its rapidly increasing concentration. Deforestation strongly affects the natural reduction of CO{sub 2} by water into carbohydrates by photosynthesis. Industrial utilization of CO{sub 2} by heterogeneous catalytic reactions can be one of the effective ways to cut the CO{sub 2} level. The first step in catalytic reaction of CO{sub 2} is the adsorption. The objective of this study is to investigate the adsorption of CO{sub 2} on the Rh/Al{sub 2}O{sub 3} surfaces. Rh is selected for this study because of its unique activity to catalyze a number of CO{sub 2} related reactions. In situ infrared results show that CO{sub 2} adsorbed on the alumina oxide support as bidentate carbonate and non-coordinated carbon which are the dominant species during the CO{sub 2} adsorption.

  16. Effect of nitric acid treatment on activated carbon derived from oil palm shell

    NASA Astrophysics Data System (ADS)

    Allwar, Allwar; Hartati, Retno; Fatimah, Is

    2017-03-01

    The primary object of this work is to study the effect of nitric acid on the porous and morphology structure of activated carbon. Production of activated carbon from oil palm shell was prepared with pyrolysis process at temperature 900°C and by introduction of 10 M nitric acid. Determination of surface area, pore volume and pore size distribution of activated carbon was conducted by the N2 adsorption-desorption isotherm at 77 K. Morphology structure and elemental micro-analysis of activated carbon were estimated by Scanning Electron Microscopy (SEM) and energy dispersive X-ray (EDX), respectively. The result shows that activated carbon after treating with nitric acid proved an increasing porous characteristics involving surface area, pore volume and pore size distribution. It also could remove the contaminants including metals and exhibit an increasing of pores and crevices all over the surface.

  17. Minimized natural versions of fungal ribotoxins show improved active site plasticity.

    PubMed

    Maestro-López, Moisés; Olombrada, Miriam; García-Ortega, Lucía; Serrano-González, Daniel; Lacadena, Javier; Oñaderra, Mercedes; Gavilanes, José G; Martínez-Del-Pozo, Álvaro

    2017-04-01

    Fungal ribotoxins are highly specific extracellular RNases which cleave a single phosphodiester bond at the ribosomal sarcin-ricin loop, inhibiting protein biosynthesis by interfering with elongation factors. Most ribotoxins show high degree of conservation, with similar sizes and amino acid sequence identities above 85%. Only two exceptions are known: hirsutellin A and anisoplin, produced by the entomopathogenic fungi Hirsutella thompsonii and Metarhizium anisopliae, respectively. Both proteins are similar but smaller than the other known ribotoxins (130 vs 150 amino acids), displaying only about 25% sequence identity with them. They can be considered minimized natural versions of their larger counterparts, best represented by α-sarcin. The conserved α-sarcin active site residue Tyr48 has been replaced by the geometrically equivalent Asp, present in the minimized ribotoxins, to produce and characterize the corresponding mutant. As a control, the inverse anisoplin mutant (D43Y) has been also studied. The results show how the smaller versions of ribotoxins represent an optimum compromise among conformational freedom, stability, specificity, and active-site plasticity which allow these toxic proteins to accommodate the characteristic abilities of ribotoxins into a shorter amino acid sequence and more stable structure of intermediate size between that of other nontoxic fungal RNases and previously known larger ribotoxins.

  18. Tannic acid modified silver nanoparticles show antiviral activity in herpes simplex virus type 2 infection.

    PubMed

    Orlowski, Piotr; Tomaszewska, Emilia; Gniadek, Marianna; Baska, Piotr; Nowakowska, Julita; Sokolowska, Justyna; Nowak, Zuzanna; Donten, Mikolaj; Celichowski, Grzegorz; Grobelny, Jaroslaw; Krzyzowska, Malgorzata

    2014-01-01

    The interaction between silver nanoparticles and herpesviruses is attracting great interest due to their antiviral activity and possibility to use as microbicides for oral and anogenital herpes. In this work, we demonstrate that tannic acid modified silver nanoparticles sized 13 nm, 33 nm and 46 nm are capable of reducing HSV-2 infectivity both in vitro and in vivo. The antiviral activity of tannic acid modified silver nanoparticles was size-related, required direct interaction and blocked virus attachment, penetration and further spread. All tested tannic acid modified silver nanoparticles reduced both infection and inflammatory reaction in the mouse model of HSV-2 infection when used at infection or for a post-infection treatment. Smaller-sized nanoparticles induced production of cytokines and chemokines important for anti-viral response. The corresponding control buffers with tannic acid showed inferior antiviral effects in vitro and were ineffective in blocking in vivo infection. Our results show that tannic acid modified silver nanoparticles are good candidates for microbicides used in treatment of herpesvirus infections.

  19. Children with High Functioning Autism show increased prefrontal and temporal cortex activity during error monitoring

    PubMed Central

    Goldberg, Melissa C.; Spinelli, Simona; Joel, Suresh; Pekar, James J.; Denckla, Martha B.; Mostofsky, Stewart H.

    2010-01-01

    Evidence exists for deficits in error monitoring in autism. These deficits may be particularly important because they may contribute to excessive perseveration and repetitive behavior in autism. We examined the neural correlates of error monitoring using fMRI in 8–12-year-old children with high-functioning autism (HFA, n=11) and typically developing children (TD, n=15) during performance of a Go/No-Go task by comparing the neural correlates of commission errors versus correct response inhibition trials. Compared to TD children, children with HFA showed increased BOLD fMRI signal in the anterior medial prefrontal cortex (amPFC) and the left superior temporal gyrus (STempG) during commission error (versus correct inhibition) trials. A follow-up region-of-interest analysis also showed increased BOLD signal in the right insula in HFA compared to TD controls. Our findings of increased amPFC and STempG activity in HFA, together with the increased activity in the insula, suggest a greater attention towards the internally-driven emotional state associated with making an error in children with HFA. Since error monitoring occurs across different cognitive tasks throughout daily life, an increased emotional reaction to errors may have important consequences for early learning processes. PMID:21151713

  20. CpG oligodeoxynucleotides with double stem-loops show strong immunostimulatory activity.

    PubMed

    Yang, Liang; Wu, Xiuli; Wan, Min; Yu, Yue; Yu, Yongli; Wang, Liying

    2013-01-01

    Based on the current understanding of TLR9 recognition of CpG ODN, we have tried to design a series of CpG ODNs that display double stem-loops when being analyzed for their secondary structures using 'mfold web server'. Proliferation of human PBMC and bioassay for IFN production were used as technical platforms in primary screening. Interestingly, two of them, designated as DSL01 and D-SL03, belonging to B class CpG ODN and C class CpG ODN respectively, showed vigorous immunostimulatory activity and were chosen for further tests. Flow cytometry analysis showed that both of them could activate human B cells, NK cells, mononuclear cells and T cells and up-regulate expression of CD80, CD86 and HLA-DR on the surface of subsets in human PBMCs. Furthermore, we demonstrated that those two ODNs potently stimulated proliferation of PBMC/splenocytes obtained from diverse vertebrate species. Noticeably, both of them displayed anti-breast cancer effect in mice when administered by peritumoral injection.

  1. Tannic Acid Modified Silver Nanoparticles Show Antiviral Activity in Herpes Simplex Virus Type 2 Infection

    PubMed Central

    Orlowski, Piotr; Tomaszewska, Emilia; Gniadek, Marianna; Baska, Piotr; Nowakowska, Julita; Sokolowska, Justyna; Nowak, Zuzanna; Donten, Mikolaj; Celichowski, Grzegorz; Grobelny, Jaroslaw; Krzyzowska, Malgorzata

    2014-01-01

    The interaction between silver nanoparticles and herpesviruses is attracting great interest due to their antiviral activity and possibility to use as microbicides for oral and anogenital herpes. In this work, we demonstrate that tannic acid modified silver nanoparticles sized 13 nm, 33 nm and 46 nm are capable of reducing HSV-2 infectivity both in vitro and in vivo. The antiviral activity of tannic acid modified silver nanoparticles was size-related, required direct interaction and blocked virus attachment, penetration and further spread. All tested tannic acid modified silver nanoparticles reduced both infection and inflammatory reaction in the mouse model of HSV-2 infection when used at infection or for a post-infection treatment. Smaller-sized nanoparticles induced production of cytokines and chemokines important for anti-viral response. The corresponding control buffers with tannic acid showed inferior antiviral effects in vitro and were ineffective in blocking in vivo infection. Our results show that tannic acid modified silver nanoparticles are good candidates for microbicides used in treatment of herpesvirus infections. PMID:25117537

  2. Staurosporine shows insecticidal activity against Mythimna separata Walker (Lepidoptera: Noctuidae) potentially via induction of apoptosis.

    PubMed

    Zhang, Yang; Liu, Songlin; Yang, Xing; Yang, Mingjun; Xu, Wenping; Li, Yaxiao; Tao, Liming

    2016-03-01

    Staurosporine (STS), a wide-spectrum kinase inhibitor, is widely used in studies of apoptosis in mammalian cells. However, its physiological and mechanistic effects have never been clearly defined in insect cells, and other applications of STS have rarely been reported. The present study reveals the insecticidal activity of STS on larvae of Mythimna separata Walker, and the apoptotic mechanism induced by STS on lepidopteran Sf9 cell lines. We demonstrate that the viability of Sf9 cells is inhibited by STS in a time- and concentration-dependent manner. Intracellular biochemical assays show that STS-induced apoptosis of Sf9 cells coincides with a decrease in the mitochondrial membrane potential, the release of cytochrome c into the cytosol, a significant increase of the Bax/Bcl-2 ratio, and a marked activation of caspase-9 and caspase-3. These results indicate that a mitochondrial-dependent intrinsic pathway contributes to STS induced caspase-3 activation and apoptosis in Sf9 cells which is homologous to the mechanisms in mammalian cells. This study contributes to our understanding of the mechanism of insect cell apoptosis and suggests a possible new application of STS as a potential insecticide against Lepidopteran insect pests in agriculture.

  3. Adolescent earthquake survivors' show increased prefrontal cortex activation to masked earthquake images as adults.

    PubMed

    Du, Xue; Wei, Dongtao; Ganzel, Barbara L; Kim, Pilyoung; Zhang, Qinglin; Qiu, Jiang

    2015-03-01

    The great Sichuan earthquake in China on May 12, 2008 was a traumatic event to many who live near the earthquake area. However, at present, there are few studies that explore the long-term impact of the adolescent trauma exposure on adults' brain function. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate the brain activation evoked by masked trauma-related stimuli (earthquake versus neutral images) in 14 adults who lived near the epicenter of the great Sichuan earthquake when they were adolescents (trauma-exposed group) and 14 adults who lived farther from the epicenter of the earthquake when they were adolescents (control group). Compared with the control group, the trauma-exposed group showed significant elevation of activation in the right anterior cingulate cortex (ACC) and the medial prefrontal cortex (MPFC) in response to masked earthquake-related images. In the trauma-exposed group, the right ACC activation was negatively correlated with the frequency of symptoms of post-traumatic stress disorder (PTSD). These findings differ markedly from the long-term effects of trauma exposure in adults. This suggests that trauma exposure during adolescence may have a unique long-term impact on ACC/MPFC function, top-down modulation of trauma-related information, and subsequent symptoms of PTSD.

  4. Men and women show distinct brain activations during imagery of sexual and emotional infidelity.

    PubMed

    Takahashi, Hidehiko; Matsuura, Masato; Yahata, Noriaki; Koeda, Michihiko; Suhara, Tetsuya; Okubo, Yoshiro

    2006-09-01

    Jealousy-related behaviors such as intimate partner violence and morbid jealousy are more common in males. Principal questionnaire studies suggest that men and women have different modules to process cues of sexual and emotional infidelity. We aimed to elucidate the neural response to sentences depicting sexual and emotional infidelity in men and women using functional magnetic resonance imaging. Although there was no sex difference in the self-rating score of jealousy for sexual and emotional infidelity, men and women showed different brain activation patterns in response to the two types of infidelity. During jealous conditions, men demonstrated greater activation than women in the brain regions involved in sexual/aggressive behaviors such as the amygdala and hypothalamus. In contrast, women demonstrated greater activation in the posterior superior temporal sulcus. Our fMRI results are in favor of the notion that men and women have different neuropsychological modules to process sexual and emotional infidelity. Our findings might contribute to a better understanding of the neural basis of the jealousy-related behaviors predominantly observed in males.

  5. Preparation of nitrogen-enriched activated carbons from brown coal

    SciTech Connect

    Robert Pietrzak; Helena Wachowska; Piotr Nowicki

    2006-05-15

    Nitrogen-enriched activated carbons were prepared from a Polish brown coal. Nitrogen was introduced from urea at 350{sup o}C in an oxidizing atmosphere both to carbonizates obtained at 500-700{sup o}C and to activated carbons prepared from them. The activation was performed at 800{sup o}C with KOH in argon. It has been observed that the carbonization temperature determines the amount of nitrogen that is incorporated (DC5U, 8.4 wt % N{sup daf}; DC6U, 6.3 wt % N{sup daf}; and DC7U, 5.4 wt % N{sup daf}). X-ray photoelectron spectroscopy (XPS) measurements have shown that nitrogen introduced both at the stage of carbonizates and at the stage of activated carbons occurs mainly as -6, -5, and imine, amine and amide groups. On the other hand, the activation of carbons enriched with nitrogen results in the formation of pyridonic nitrogen and N-Q. The introduction of nitrogen at the activated carbon stage leads to a slight decrease in surface area. It has been proven that the most effective way of preparing microporous activated carbons enriched with nitrogen to a considerable extent and having high surface area ({approximately} 3000 m{sup 2}/g) is the following: carbonization - activation - reaction with urea. 40 refs., 1 fig., 6 tabs.

  6. Characterization and restoration of performance of {open_quotes}aged{close_quotes} radioiodine removing activated carbons

    SciTech Connect

    Freeman, W.P.

    1997-08-01

    The degradation of radioiodine removal performance for impregnated activated carbons because of ageing is well established. However, the causes for this degradation remain unclear. One theory is that this reduction in performance from the ageing process results from an oxidation of the surface of the carbon. Radioiodine removing activated carbons that failed radioiodine removal tests showed an oxidized surface that had become hydrophilic compared with new carbons. We attempted to restore the performance of these {open_quotes}failed{close_quotes} carbons with a combination of thermal and chemical treatment. The results of these investigations are presented and discussed with the view of extending the life of radioiodine removing activated carbons. 4 refs., 2 tabs.

  7. An inhibitory RNA aptamer against the lambda cI repressor shows transcriptional activator activity in vivo.

    PubMed

    Ohuchi, Shoji; Suess, Beatrix

    2017-04-13

    An RNA aptamer is one of the promising components for constructing artificial genetic circuits. In this study, we developed a transcriptional activator based on an RNA aptamer against one of the most frequently applied repressor proteins, lambda phage cI. In vitro selection (SELEX), followed by in vivo screening identified an RNA aptamer with the intended transcriptional activator activity from an RNA pool containing a 40-nucleotide long random region. Quantitative analysis showed 35-fold elevation of reporter expression upon aptamer expression. These results suggest that the diversity of artificial transcriptional activators can be extended by employing RNA aptamers against repressor proteins to broaden the tools available for constructing genetic circuits. This article is protected by copyright. All rights reserved.

  8. Microbial Enzyme Activity and Carbon Cycling in Grassland Soil Fractions

    NASA Astrophysics Data System (ADS)

    Allison, S. D.; Jastrow, J. D.

    2004-12-01

    Extracellular enzymes are necessary to degrade complex organic compounds present in soils. Using physical fractionation procedures, we tested whether old soil carbon is spatially isolated from degradative enzymes across a prairie restoration chronosequence in Illinois, USA. We found that carbon-degrading enzymes were abundant in all soil fractions, including macroaggregates, microaggregates, and the clay fraction, which contains carbon with a mean residence time of ~200 years. The activities of two cellulose-degrading enzymes and a chitin-degrading enzyme were 2-10 times greater in organic matter fractions than in bulk soil, consistent with the rapid turnover of these fractions. Polyphenol oxidase activity was 3 times greater in the clay fraction than in the bulk soil, despite very slow carbon turnover in this fraction. Changes in enzyme activity across the restoration chronosequence were small once adjusted for increases in soil carbon concentration, although polyphenol oxidase activity per unit carbon declined by 50% in native prairie versus cultivated soil. These results are consistent with a `two-pool' model of enzyme and carbon turnover in grassland soils. In light organic matter fractions, enzyme production and carbon turnover both occur rapidly. However, in mineral-dominated fractions, both enzymes and their carbon substrates are immobilized on mineral surfaces, leading to slow turnover. Soil carbon accumulation in the clay fraction and across the prairie restoration chronosequence probably reflects increasing physical isolation of enzymes and substrates on the molecular scale, rather than the micron to millimeter scale.

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

    PubMed

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

    2015-03-01

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

  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. RNA-stable-isotope probing shows utilization of carbon from inulin by specific bacterial populations in the rat large bowel.

    PubMed

    Tannock, Gerald W; Lawley, Blair; Munro, Karen; Sims, Ian M; Lee, Julian; Butts, Christine A; Roy, Nicole

    2014-04-01

    Knowledge of the trophisms that underpin bowel microbiota composition is required in order to understand its complex phylogeny and function. Stable-isotope ((13)C)-labeled inulin was added to the diet of rats on a single occasion in order to detect utilization of inulin-derived substrates by particular members of the cecal microbiota. Cecal digesta from Fibruline-inulin-fed rats was collected prior to (0 h) and at 6, 12, 18 and 24 h following provision of the [(13)C]inulin diet. RNA was extracted from these cecal specimens and fractionated in isopycnic buoyant density gradients in order to detect (13)C-labeled nucleic acid originating in bacterial cells that had metabolized the labeled dietary constituent. RNA extracted from specimens collected after provision of the labeled diet was more dense than 0-h RNA. Sequencing of 16S rRNA genes amplified from cDNA obtained from these fractions showed that Bacteroides uniformis, Blautia glucerasea, Clostridium indolis, and Bifidobacterium animalis were the main users of the (13)C-labeled substrate. Culture-based studies of strains of these bacterial species enabled trophisms associated with inulin and its hydrolysis products to be identified. B. uniformis utilized Fibruline-inulin for growth, whereas the other species used fructo-oligosaccharide and monosaccharides. Thus, RNA-stable-isotope probing (RNA-SIP) provided new information about the use of carbon from inulin in microbiota metabolism.

  12. Indonesian fire activity and smoke pollution in 2015 show persistent nonlinear sensitivity to El Niño-induced drought

    NASA Astrophysics Data System (ADS)

    Field, Robert D.; van der Werf, Guido R.; Fanin, Thierry; Fetzer, Eric J.; Fuller, Ryan; Jethva, Hiren; Levy, Robert; Livesey, Nathaniel J.; Luo, Ming; Torres, Omar; Worden, Helen M.

    2016-08-01

    The 2015 fire season and related smoke pollution in Indonesia was more severe than the major 2006 episode, making it the most severe season observed by the NASA Earth Observing System satellites that go back to the early 2000s, namely active fire detections from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS), MODIS aerosol optical depth, Terra Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO), Aqua Atmospheric Infrared Sounder (AIRS) CO, Aura Ozone Monitoring Instrument (OMI) aerosol index, and Aura Microwave Limb Sounder (MLS) CO. The MLS CO in the upper troposphere showed a plume of pollution stretching from East Africa to the western Pacific Ocean that persisted for 2 mo. Longer-term records of airport visibility in Sumatra and Kalimantan show that 2015 ranked after 1997 and alongside 1991 and 1994 as among the worst episodes on record. Analysis of yearly dry season rainfall from the Tropical Rainfall Measurement Mission (TRMM) and rain gauges shows that, due to the continued use of fire to clear and prepare land on degraded peat, the Indonesian fire environment continues to have nonlinear sensitivity to dry conditions during prolonged periods with less than 4 mm/d of precipitation, and this sensitivity appears to have increased over Kalimantan. Without significant reforms in land use and the adoption of early warning triggers tied to precipitation forecasts, these intense fire episodes will reoccur during future droughts, usually associated with El Niño events.

  13. Indonesian fire activity and smoke pollution in 2015 show persistent nonlinear sensitivity to El Niño-induced drought.

    PubMed

    Field, Robert D; van der Werf, Guido R; Fanin, Thierry; Fetzer, Eric J; Fuller, Ryan; Jethva, Hiren; Levy, Robert; Livesey, Nathaniel J; Luo, Ming; Torres, Omar; Worden, Helen M

    2016-08-16

    The 2015 fire season and related smoke pollution in Indonesia was more severe than the major 2006 episode, making it the most severe season observed by the NASA Earth Observing System satellites that go back to the early 2000s, namely active fire detections from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS), MODIS aerosol optical depth, Terra Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO), Aqua Atmospheric Infrared Sounder (AIRS) CO, Aura Ozone Monitoring Instrument (OMI) aerosol index, and Aura Microwave Limb Sounder (MLS) CO. The MLS CO in the upper troposphere showed a plume of pollution stretching from East Africa to the western Pacific Ocean that persisted for 2 mo. Longer-term records of airport visibility in Sumatra and Kalimantan show that 2015 ranked after 1997 and alongside 1991 and 1994 as among the worst episodes on record. Analysis of yearly dry season rainfall from the Tropical Rainfall Measurement Mission (TRMM) and rain gauges shows that, due to the continued use of fire to clear and prepare land on degraded peat, the Indonesian fire environment continues to have nonlinear sensitivity to dry conditions during prolonged periods with less than 4 mm/d of precipitation, and this sensitivity appears to have increased over Kalimantan. Without significant reforms in land use and the adoption of early warning triggers tied to precipitation forecasts, these intense fire episodes will reoccur during future droughts, usually associated with El Niño events.

  14. Indonesian fire activity and smoke pollution in 2015 show persistent nonlinear sensitivity to El Niño-induced drought

    PubMed Central

    Field, Robert D.; van der Werf, Guido R.; Fanin, Thierry; Fetzer, Eric J.; Fuller, Ryan; Jethva, Hiren; Levy, Robert; Livesey, Nathaniel J.; Luo, Ming; Torres, Omar; Worden, Helen M.

    2016-01-01

    The 2015 fire season and related smoke pollution in Indonesia was more severe than the major 2006 episode, making it the most severe season observed by the NASA Earth Observing System satellites that go back to the early 2000s, namely active fire detections from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS), MODIS aerosol optical depth, Terra Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO), Aqua Atmospheric Infrared Sounder (AIRS) CO, Aura Ozone Monitoring Instrument (OMI) aerosol index, and Aura Microwave Limb Sounder (MLS) CO. The MLS CO in the upper troposphere showed a plume of pollution stretching from East Africa to the western Pacific Ocean that persisted for 2 mo. Longer-term records of airport visibility in Sumatra and Kalimantan show that 2015 ranked after 1997 and alongside 1991 and 1994 as among the worst episodes on record. Analysis of yearly dry season rainfall from the Tropical Rainfall Measurement Mission (TRMM) and rain gauges shows that, due to the continued use of fire to clear and prepare land on degraded peat, the Indonesian fire environment continues to have nonlinear sensitivity to dry conditions during prolonged periods with less than 4 mm/d of precipitation, and this sensitivity appears to have increased over Kalimantan. Without significant reforms in land use and the adoption of early warning triggers tied to precipitation forecasts, these intense fire episodes will reoccur during future droughts, usually associated with El Niño events. PMID:27482096

  15. 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.

  16. The adsorption of sympathomimetic agents by activated carbon hemoperfusion.

    PubMed

    Horres, C R; Hill, J B; Ellis, F W

    1976-01-01

    Sympathomimetic agents with mixed and pure alpha and beta adrenergic activity are adsorbed by coconut shell activated carbon from blood, sufficiently rapidly to markedly reduce the activity of these agents. The results of this study suggest that the site of injection of sympathomimetic agents being considered for correcting hypotension during activated carbon hemoperfusion be selected to permit systemic mixing before circulation into the adsorption device.

  17. 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.

  18. Magnetic graphitic carbon nitride: its application in the C-H activation of amines.

    PubMed

    Verma, Sanny; Nasir Baig, R B; Han, Changseok; Nadagouda, Mallikarjuna N; Varma, Rajender S

    2015-11-04

    Magnetic graphitic carbon nitride, Fe@g-C3N4, has been synthesized by adorning a graphitic carbon nitride (g-C3N4) support with iron oxide via non-covalent interaction. The magnetically recyclable catalyst showed excellent reactivity for the expeditious C-H activation and cyanation of amines.

  19. Magnetic graphitic carbon nitride: its application in the C–H activation of amines

    EPA Science Inventory

    Magnetic graphitic carbon nitride, Fe@g-C3N4, has been synthesized by adorning graphitic carbon nitride (g-C3N4) support with iron oxide via non-covalent interaction. The magnetically recyclable catalyst showed excellent reactivity for expeditious C-H activation and cyanation of ...

  20. 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.

  1. Modelling Cr(VI) removal by a combined carbon-activated sludge system.

    PubMed

    Orozco, A Micaela Ferro; Contreras, Edgardo M; Zaritzky, Noemí E

    2008-01-15

    The combined carbon-activated sludge process has been proposed as an alternative to protect the biomass against toxic substances in wastewaters; however, the information about the effect of powdered-activated carbon (PAC) addition in activated sludge reactors for the treatment of wastewaters containing Cr(VI) is limited. The objectives of the present study were: (a) to evaluate the removal of hexavalent chromium by (i) activated sludge microorganisms in aerobic batch reactors, (ii) powdered-activated carbon, and (iii) the combined action of powdered-activated carbon and biomass; (b) to propose mathematical models that interpret the experimental results. Different Cr(VI) removal systems were tested: (S1) biomass (activated sludge), (S2) PAC, and (S3) the combined activated carbon-biomass system. A Monod-based mathematical model was used to describe the kinetics of Cr(VI) removal in the system S1. A first-order kinetics with respect to Cr(VI) and PAC respectively, was proposed to model the removal of Cr(VI) in the system S2. Cr(VI) removal in the combined carbon-biomass system (S3) was faster than both Cr(VI) removal using PAC or activated sludge individually. Results showed that the removal of Cr(VI) using the activated carbon-biomass system (S3) was adequately described by combining the kinetic equations proposed for the systems S1 and S2.

  2. Optimization of microporous palm shell activated carbon production for flue gas desulphurization: experimental and statistical studies.

    PubMed

    Sumathi, S; Bhatia, S; Lee, K T; Mohamed, A R

    2009-02-01

    Optimizing the production of microporous activated carbon from waste palm shell was done by applying experimental design methodology. The product, palm shell activated carbon was tested for removal of SO2 gas from flue gas. The activated carbon production was mathematically described as a function of parameters such as flow rate, activation time and activation temperature of carbonization. These parameters were modeled using response surface methodology. The experiments were carried out as a central composite design consisting of 32 experiments. Quadratic models were developed for surface area, total pore volume, and microporosity in term of micropore fraction. The models were used to obtain the optimum process condition for the production of microporous palm shell activated carbon useful for SO2 removal. The optimized palm shell activated carbon with surface area of 973 m(2)/g, total pore volume of 0.78 cc/g and micropore fraction of 70.5% showed an excellent agreement with the amount predicted by the statistical analysis. Palm shell activated carbon with higher surface area and microporosity fraction showed good adsorption affinity for SO2 removal.

  3. The metastasis-promoting phosphatase PRL-3 shows activity toward phosphoinositides.

    PubMed

    McParland, Victoria; Varsano, Giulia; Li, Xun; Thornton, Janet; Baby, Jancy; Aravind, Ajay; Meyer, Christoph; Pavic, Karolina; Rios, Pablo; Köhn, Maja

    2011-09-06

    Phosphatase of regenerating liver 3 (PRL-3) is suggested as a biomarker and therapeutic target in several cancers. It has a well-established causative role in cancer metastasis. However, little is known about its natural substrates, pathways, and biological functions, and only a few protein substrates have been suggested so far. To improve our understanding of the substrate specificity and molecular determinants of PRL-3 activity, the wild-type (WT) protein, two supposedly catalytically inactive mutants D72A and C104S, and the reported hyperactive mutant A111S were tested in vitro for substrate specificity and activity toward phosphopeptides and phosphoinositides (PIPs), their structural stability, and their ability to promote cell migration using stable HEK293 cell lines. We discovered that WT PRL-3 does not dephosphorylate the tested phosphopeptides in vitro. However, as shown by two complementary biochemical assays, PRL-3 is active toward the phosphoinositide PI(4,5)P(2). Our experimental results substantiated by molecular docking studies suggest that PRL-3 is a phosphatidylinositol 5-phosphatase. The C104S variant was shown to be not only catalytically inactive but also structurally destabilized and unable to promote cell migration, whereas WT PRL-3 promotes cell migration. The D72A mutant is structurally stable and does not dephosphorylate the unnatural substrate 3-O-methylfluorescein phosphate (OMFP). However, we observed residual in vitro activity of D72A against PI(4,5)P(2), and in accordance with this, it exhibits the same cellular phenotype as WT PRL-3. Our analysis of the A111S variant shows that the hyperactivity toward the unnatural OMFP substrate is not apparent in dephosphorylation assays with phosphoinositides: the mutant is completely inactive against PIPs. We observed significant structural destabilization of this variant. The cellular phenotype of this mutant equals that of the catalytically inactive C104S mutant. These results provide a possible

  4. Etoposide incorporated into camel milk phospholipids liposomes shows increased activity against fibrosarcoma in a mouse model.

    PubMed

    Maswadeh, Hamzah M; Aljarbou, Ahmad N; Alorainy, Mohammed S; Alsharidah, Mansour S; Khan, Masood A

    2015-01-01

    Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS). Anticancer drug etoposide (ETP) was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP) and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes) and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes). The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs.

  5. Cysteamine, the natural metabolite of pantetheinase, shows specific activity against Plasmodium.

    PubMed

    Min-Oo, Gundula; Ayi, Kodjo; Bongfen, Silayuv E; Tam, Mifong; Radovanovic, Irena; Gauthier, Susan; Santiago, Helton; Rothfuchs, Antonio Gigliotti; Roffê, Ester; Sher, Alan; Mullick, Alaka; Fortin, Anny; Stevenson, Mary M; Kain, Kevin C; Gros, Philippe

    2010-08-01

    In mice, loss of pantetheinase activity causes susceptibility to infection with Plasmodium chabaudi AS. Treatment of mice with the pantetheinase metabolite cysteamine reduces blood-stage replication of P. chabaudi and significantly increases survival. Similarly, a short exposure of Plasmodium to cysteamine ex vivo is sufficient to suppress parasite infectivity in vivo. This effect of cysteamine is specific and not observed with a related thiol (dimercaptosuccinic acid) or with the pantethine precursor of cysteamine. Also, cysteamine does not protect against infection with the parasite Trypanosoma cruzi or the fungal pathogen Candida albicans, suggesting cysteamine acts directly against the parasite and does not modulate host inflammatory response. Cysteamine exposure also blocks replication of P. falciparum in vitro; moreover, these treated parasites show higher levels of intact hemoglobin. This study highlights the in vivo action of cysteamine against Plasmodium and provides further evidence for the involvement of pantetheinase in host response to this infection.

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

    SciTech Connect

    Edwin Olson; Lucinda Hamre; John Pavlish; Blaise Mibeck

    2009-03-25

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

  7. Acidophilic actinobacteria synthesised silver nanoparticles showed remarkable activity against fungi-causing superficial mycoses in humans.

    PubMed

    Anasane, N; Golińska, P; Wypij, M; Rathod, D; Dahm, H; Rai, M

    2016-03-01

    Superficial mycoses are limited to the most external part of the skin and hair and caused by Malassezia sp., Trichophyton sp. and Candida sp. We report extracellular biosynthesis of silver nanoparticles (AgNPs) by acidophilic actinobacteria (SF23, C9) and its in vitro antifungal activity against fungi-causing superficial mycoses. The phylogenetic analysis based on the 16S rRNA gene sequence of strains SF23 and C9 showed that they are most closely related to Pilimelia columellifera subsp. pallida GU269552(T). The detection of AgNPs was confirmed by visual observation of colour changes from colourless to brown, and UV-vis spectrophotometer analysis, which showed peaks at 432 and 427 nm, respectively. These AgNPs were further characterised by nanoparticle tracking analysis (NTA), Zeta potential, Fourier-transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The FTIR analysis exhibited the presence of proteins as capping agents. The TEM analysis revealed the formation of spherical and polydispersed nanoparticles in the size range of 4-36 nm and 8-60 nm, respectively. The biosynthesised AgNPs were screened against fungi-causing superficial mycoses viz., Malassezia furfur, Trichophyton rubrum, Candida albicans and C. tropicalis. The highest antifungal activity of AgNPs from SF23 and C9 against T. rubrum and the least against M. furfur and C. albicans was observed as compared to other tested fungi. The biosynthesised AgNPs were found to be potential anti-antifungal agent against fungi-causing superficial mycoses.

  8. 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 700°C and activated by water steam at 550°C. It was found that resorcinol polymerization is easier than catechol and occurred at 90°C while for polymerization of catechol elevated temperature of 120°C 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.

  9. DC-159a Shows Inhibitory Activity against DNA Gyrases of Mycobacterium leprae

    PubMed Central

    Yamaguchi, Tomoyuki; Yokoyama, Kazumasa; Nakajima, Chie

    2016-01-01

    Background Fluoroquinolones are a class of antibacterial agents used for leprosy treatment. Some new fluoroquinolones have been attracting interest due to their remarkable potency that is reportedly better than that of ofloxacin, the fluoroquinolone currently recommended for treatment of leprosy. For example, DC-159a, a recently developed 8-methoxy fluoroquinolone, has been found to be highly potent against various bacterial species. Nonetheless, the efficacy of DC-159a against Mycobacterium leprae is yet to be examined. Methodology/Principal Findings To gather data that can support highly effective fluoroquinolones as candidates for new remedies for leprosy treatment, we conducted in vitro assays to assess and compare the inhibitory activities of DC-159a and two fluoroquinolones that are already known to be more effective against M. leprae than ofloxacin. The fluoroquinolone-inhibited DNA supercoiling assay using recombinant DNA gyrases of wild type and ofloxacin-resistant M. leprae revealed that inhibitory activities of DC-159a and sitafloxacin were at most 9.8- and 11.9-fold higher than moxifloxacin. Also the fluoroquinolone–mediated cleavage assay showed that potencies of those drugs were at most 13.5- and 9.8-fold higher than moxifloxacin. In addition, these two drugs retained their inhibitory activities even against DNA gyrases of ofloxacin-resistant M. leprae. Conclusions/Significance The results indicated that DC-159a and sitafloxacin are more effective against wild type and mutant M. leprae DNA gyrases than moxifloxacin, suggesting that these antibacterial drugs can be good candidates that may supersede current fluoroquinolone remedies. DC-159a in particular is very promising because it is classified in a subgroup of fluoroquinolones that is known to be less likely to cause adverse effects. Our results implied that DC-159a is well worth further investigation to ascertain its in vivo effectiveness and clinical safety for humans. PMID:27681932

  10. Physically active men show better semen parameters and hormone values than sedentary men.

    PubMed

    Vaamonde, Diana; Da Silva-Grigoletto, Marzo Edir; García-Manso, Juan Manuel; Barrera, Natalibeth; Vaamonde-Lemos, Ricardo

    2012-09-01

    Physical exercise promotes many health benefits. The present study was undertaken to assess possible semen and hormone differences among physically active (PA) subjects and sedentary subjects (SE). The analyzed qualitative sperm parameters were: volume, sperm count, motility, and morphology; where needed, additional testing was performed. The measured hormones were: follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), cortisol (C), and the ratio between T and C (T/C). Maximum oxygen consumption was also assessed to check for differences in fitness level. Statistically significant differences were found for several semen parameters such as total progressive motility (PA: 60.94 ± 5.03; SE: 56.07 ± 4.55) and morphology (PA: 15.54 ± 1.38, SE: 14.40 ± 1.15). The seminological values observed were supported by differences in hormones, with FSH, LH, and T being higher in PA than in SE (5.68 ± 2.51 vs. 3.14 ± 1.84; 5.95 ± 1.11 vs. 5.08 ± 0.98; 7.68 ± 0.77 vs. 6.49 ± 0.80, respectively). Likewise, the T/C ratio, index of anabolic versus catabolic status, was also higher in PA (0.46 ± 0.11 vs. 0.32 ± 0.07), which further supports the possibility of an improved hormonal environment. The present study shows that there are differences in semen and hormone values of physically active subjects and sedentary subjects. Physically active subjects seem to have a more anabolic hormonal environment and a healthier semen production.

  11. Sphaeropsidin A shows promising activity against drug-resistant cancer cells by targeting regulatory volume increase

    PubMed Central

    Mathieu, Véronique; Chantôme, Aurélie; Lefranc, Florence; Cimmino, Alessio; Miklos, Walter; Paulitschke, Verena; Mohr, Thomas; Maddau, Lucia; Kornienko, Alexander; Berger, Walter; Vandier, Christophe; Evidente, Antonio; Delpire, Eric; Kiss, Robert

    2016-01-01

    Despite the recent advances in the treatment of tumors with intrinsic chemotherapy resistance, such as melanoma and renal cancers, their prognosis remains poor and new chemical agents with promising activity against these cancers are urgently needed. Sphaeropsidin A, a fungal metabolite whose anticancer potential had previously received little attention, was isolated from Diplodia cupressi and found to display specific anticancer activity in vitro against melanoma and kidney cancer subpanels in the National Cancer Institute (NCI) 60-cell line screen. The NCI data revealed a mean LC50 of ca. 10 μM and a cellular sensitivity profile that did not match that of any other agent in the 765,000 compound database. Subsequent mechanistic studies in melanoma and other multidrug-resistant in vitro cancer models showed that sphaeropsidin A can overcome apoptosis as well as multidrug resistance by inducing a marked and rapid cellular shrinkage related to the loss of intracellular Cl− and the decreased HCO3− concentration in the culture supernatant. These changes in ion homeostasis and the absence of effects on the plasma membrane potential were attributed to the sphaeropsidin A-induced impairment of regulatory volume increase (RVI). Preliminary results also indicate that depending on the type of cancer, the sphaeropsidin A effects on RVI could be related to Na–K–2Cl electroneutral cotransporter or Cl−/HCO3− anion exchanger(s) targeting. This study underscores the modulation of ion-transporter activity as a promising therapeutic strategy to combat drug-resistant cancers and identifies the fungal metabolite, sphaeropsidin A, as a lead to develop anticancer agents targeting RVI in cancer cells. PMID:25868554

  12. Novel, potent and selective inhibitors of protein kinase C show oral anti-inflammatory activity.

    PubMed

    Nixon, J S; Bishop, J; Bradshaw, D; Davis, P D; Hill, C H; Elliott, L H; Kumar, H; Lawton, G; Lewis, E J; Mulqueen, M

    1991-01-01

    Clarification of the precise role of protein kinase C (PKC) in cellular functional responses has been hampered by a lack of potent, selective inhibitors. The structural lead provided by staurosporine, a potent but non-selective protein kinase (PK) inhibitor, was used to derive a series of bis(indolyl)maleimides of which the most potent, Ro 31-8425 (I50: PKC = 8 nM) showed 350-fold selectivity for PKC over cAMP-dependent protein kinase. Ro 31-8425 antagonised cellular processes triggered by phorbol esters (potent, specific PKC activators) and inhibited the allogeneic mixed lymphocyte reaction, suggesting a role for PKC in T-cell activation. Methylation of the primary amine in Ro 31-8425 produced an analogue. Ro 31-8830 which, when administered orally, produced a dose-dependent inhibition of a phorbol ester-induced paw oedema in mice (minimum effective dose = 15 mg/kg). Ro 31-8830 also selectively inhibited the secondary inflammation in a developing adjuvant arthritis model in the rat. The results presented here suggest that these selective inhibitors of PKC may have therapeutic value in the treatment of T-cell-mediated autoimmune diseases.

  13. Aluminum hydroxide nanoparticles show a stronger vaccine adjuvant activity than traditional aluminum hydroxide microparticles.

    PubMed

    Li, Xinran; Aldayel, Abdulaziz M; Cui, Zhengrong

    2014-01-10

    Aluminum hydroxide is used as a vaccine adjuvant in various human vaccines. Unfortunately, despite its favorable safety profile, aluminum hydroxide can only weakly or moderately potentiate antigen-specific antibody responses. When dispersed in an aqueous solution, aluminum hydroxide forms particulates of 1-20μm. There is increasing evidence that nanoparticles around or less than 200nm as vaccine or antigen carriers have a more potent adjuvant activity than large microparticles. In the present study, we synthesized aluminum hydroxide nanoparticles of 112nm. Using ovalbumin and Bacillus anthracis protective antigen protein as model antigens, we showed that protein antigens adsorbed on the aluminum hydroxide nanoparticles induced a stronger antigen-specific antibody response than the same protein antigens adsorbed on the traditional aluminum hydroxide microparticles of around 9.3μm. The potent adjuvant activity of the aluminum hydroxide nanoparticles was likely related to their ability to more effectively facilitate the uptake of the antigens adsorbed on them by antigen-presenting cells. Finally, the local inflammation induced by aluminum hydroxide nanoparticles in the injection sites was milder than that induced by microparticles. Simply reducing the particle size of the traditional aluminum hydroxide adjuvant into nanometers represents a novel and effective approach to improve its adjuvanticity.

  14. Boehmenan, a lignan from Hibiscus ficulneus, showed Wnt signal inhibitory activity.

    PubMed

    Shono, Takumi; Ishikawa, Naoki; Toume, Kazufumi; Arai, Midori A; Ahmed, Firoj; Sadhu, Samir K; Ishibashi, Masami

    2015-07-15

    The Wnt signal pathway modulates numerous biological processes, and its aberrant activation is related to various diseases. Therefore, inhibition of the Wnt signal may provide an effective (or efficient) strategy for these diseases. Cell-based luciferase assay targeting the Wnt signal (TOP assay) revealed that Hibiscus ficulneus extract inhibited the Wnt signal. The activity-guided isolation of the MeOH extract of H. ficulneus stems yielded four known (1-4) lignans along with myriceric acid (5). Compounds 1-4 potently inhibited the Wnt signal with TOPflash IC50 values of 1.0, 4.5, 6.3, and 1.9 μM, respectively. Compound 1 exhibited cytotoxicity against both Wnt-dependent (HCT116) and Wnt-independent (RKO) cells. Western blot analysis showed that 1 decreased the expression of full, cytosolic and nuclear β-catenin along with c-myc in STF/293 cells. Our results suggested that 1 may have inhibited the Wnt signal by decreasing β-catenin levels.

  15. The left occipitotemporal cortex does not show preferential activity for words.

    PubMed

    Vogel, Alecia C; Petersen, Steven E; Schlaggar, Bradley L

    2012-12-01

    Regions in left occipitotemporal (OT) cortex, including the putative visual word form area, are among the most commonly activated in imaging studies of single-word reading. It remains unclear whether this part of the brain is more precisely characterized as specialized for words and/or letters or contains more general-use visual regions having properties useful for processing word stimuli, among others. In Analysis 1, we found no evidence of greater activity in left OT regions for words or letter strings relative to other high-spatial frequency high-contrast stimuli, including line drawings and Amharic strings (which constitute the Ethiopian writing system). In Analysis 2, we further investigated processing characteristics of OT cortex potentially useful in reading. Analysis 2 showed that a specific part of OT cortex 1) is responsive to visual feature complexity, measured by the number of strokes forming groups of letters or Amharic strings and 2) processes learned combinations of characters, such as those in words and pseudowords, as groups but does not do so in consonant and Amharic strings. Together, these results indicate that while regions of left OT cortex are not specialized for words, at least part of OT cortex has properties particularly useful for processing words and letters.

  16. Water Extract of Fructus Hordei Germinatus Shows Antihyperprolactinemia Activity via Dopamine D2 Receptor

    PubMed Central

    Wang, Xiong; Ma, Li; Zhang, En-jing; Zou, Ji-li; Guo, Hao; Peng, Si-wei; Wu, Jin-hu

    2014-01-01

    Objective. Fructus Hordei Germinatus is widely used in treating hyperprolactinemia (hyperPRL) as a kind of Chinese traditional herb in China. In this study, we investigated the anti-hyperPRL activity of water extract of Fructus Hordei Germinatus (WEFHG) and mechanism of action. Methods. Effect of WEFHG on serum prolactin (PRL), estradiol (E2), progesterone (P), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and hypothalamus protein kinase A (PKA) and cyclic adenosine monophosphate (cAMP) levels of hyperPRL rats were investigated. And effect of WEFHG on PRL secretion, D2 receptors, and dopamine transporters (DAT) was studied in MMQ, GH3, and PC12 cells, respectively. Results. WEFHG reduced the secretion of PRL in hyperPRL rats effectively. In MMQ cell, treatment with WEFHG at 1–5 mg/mL significantly suppressed PRL secretion and synthesis. Consistent with a D2-action, WEFHG did not affect PRL in rat pituitary lactotropic tumor-derived GH3 cells that lack the D2 receptor expression but significantly increased the expression of D2 receptors and DAT in PC12 cells. In addition, WEFHG reduced the cAMP and PKA levels of hypothalamus in hyperPRL rats significantly. Conclusions. WEFHG showed anti-hyperPRL activity via dopamine D2 receptor, which was related to the second messenger cAMP and PKA. PMID:25254056

  17. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    PubMed

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  18. Soil Inorganic Carbon in Deserts: Active Carbon Sink or Inert Reservoir?

    NASA Astrophysics Data System (ADS)

    Monger, H. C.; Cole, D. R.

    2011-12-01

    Soil inorganic carbon is the third largest C pool in the active global carbon cycle, containing at least 800 petagrams of carbon. Although carbonate dissolution-precipitation reactions have been understood for over a century, the role of soil inorganic carbon in carbon sequestration, and in particular pedogenic carbonate, is a deceptively complex process because it involves interdependent connections among climate, plants, microorganisms, silicate minerals, soil moisture, pH, and Ca supply via rain, dust, or in situ weathering. An understanding of soil inorganic carbon as a sink or reservoir also requires examination of the system at local to continental scales and at seasonal to millennial time scales. In desert soils studied in North America, carbon isotope ratios and radiocarbon dates were measured in combination with electron microscopy, lab and field experiments with biological calcite formation, and field measurements of carbon dioxide emissions. These investigations reveal that soil inorganic carbon is both an active sink and a inert reservoir depending on the spatial and temporal scale and source of calcium.

  19. Cellulosic carbon fibers with branching carbon nanotubes for enhanced electrochemical activities for bioprocessing applications.

    PubMed

    Zhao, Xueyan; Lu, Xin; Tze, William Tai Yin; Kim, Jungbae; Wang, Ping

    2013-09-25

    Renewable biobased carbon fibers are promising materials for large-scale electrochemical applications including chemical processing, energy storage, and biofuel cells. Their performance is, however, often limited by low activity. Herein we report that branching carbon nanotubes can enhance the activity of carbonized cellulosic fibers, such that the oxidation potential of NAD(H) was reduced to 0.55 V from 0.9 V when applied for bioprocessing. Coordinating with enzyme catalysts, such hierarchical carbon materials effectively facilitated the biotransformation of glycerol, with the total turnover number of NAD(H) over 3500 within 5 h of reaction.

  20. 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.

  1. Neural activation in the "reward circuit" shows a nonlinear response to facial attractiveness.

    PubMed

    Liang, Xiaoyun; Zebrowitz, Leslie A; Zhang, Yi

    2010-01-01

    Positive behavioral responses to attractive faces have led neuroscientists to investigate underlying neural mechanisms in a "reward circuit" that includes brain regions innervated by dopamine pathways. Using male faces ranging from attractive to extremely unattractive, disfigured ones, this study is the first to demonstrate heightened responses to both rewarding and aversive faces in numerous areas of this putative reward circuit. Parametric analyses employing orthogonal linear and nonlinear regressors revealed positive nonlinear effects in anterior cingulate cortex, lateral orbital frontal cortex (LOFC), striatum (nucleus accumbens, caudate, putamen), and ventral tegmental area, in addition to replicating previously documented linear effects in medial orbital frontal cortex (MOFC) and LOFC and nonlinear effects in amygdala and MOFC. The widespread nonlinear responses are consistent with single cell recordings in animals showing responses to both rewarding and aversive stimuli, and with some human fMRI investigations of non-face stimuli. They indicate that the reward circuit does not process face valence with any simple dissociation of function across structures. Perceiver gender modulated some responses to our male faces: Women showed stronger linear effects, and men showed stronger nonlinear effects, which may have functional implications. Our discovery of nonlinear responses to attractiveness throughout the reward circuit echoes the history of amygdala research: Early work indicated a linear response to threatening stimuli, including faces; later work also revealed a nonlinear response with heightened activation to affectively salient stimuli regardless of valence. The challenge remains to determine how such dual coding influences feelings, such as pleasure and pain, and guides goal-related behavioral responses, such as approach and avoidance.

  2. Preparation of activated carbons from raw and biotreated agricultural residues for removal of volatile organic compounds.

    PubMed

    Hsi, Hsing-Cheng; Horng, Richard S; Pan, Tai-An; Lee, Shin-Ku

    2011-05-01

    Activated carbons with diverse physical and chemical properties were produced from four agriculture residues, including raw barley husk, biotreated barley husk, rice husk, and pistachio shell. Results showed that with adequate steam activation (30-90 min, 50% H2O(g),/50% N2), activated carbons with surface areas between 360 and 950 m2 g(-1) were developed. Further increases in the activation time destroyed the pore structure of activated carbons, which resulted in a decrease in the surface area and pore volume. Biotreated agricultural residues were found to be suitable precursors for producing mesoporous activated carbons. The oxygen content of activated carbons increased with increasing activation time. Results from X-ray photoelectron spectroscopy examination further suggested that H2O molecules react with the carbon surface, enhancing the deconvoluted peak area of carbonyl and carboxyl groups. Equilibrium adsorption of toluene indicated that the adsorption capacities increased with an increase in the inlet toluene concentration and a decrease in temperature. The adsorption isotherms were successfully fitted with Freundlich, Langmuir, and Dubinin-Radushkevich equations. Activated carbons derived from agricultural residues appear to be more applicable to adsorb volatile organic compounds at a low concentration and high-temperature environment.

  3. Preparation and characterization of high surface area activated carbon from Fox nut (Euryale ferox) shell by chemical activation with H3PO4

    NASA Astrophysics Data System (ADS)

    Kumar, Arvind; Jena, Hara Mohan

    Activated carbons were prepared from Fox nutshell by chemical activation with H3PO4 in N2 atmosphere and their characteristics were studied. The effects of activation temperature and impregnation ratio were examined. N2 adsorption isotherms characterized the surface area, total pore volume, micropore volume and pore size distribution of activated carbons. Activated carbon was produced at 700 °C with a 1.5 impregnation ratio and one hour of activation time has found 2636 m2/g and 1.53 cm3/g of highest BET surface area and total pore volume, respectively. The result of Fourier-infrared spectroscopy analysis of the prepared activated carbon confirmed that the carbon has abundant functional groups on the surface. Field emission scanning electron micrographs of the prepared activated carbon showed that a porous structure formed during activation.

  4. [Preparation, characterization and adsorption performance of mesoporous activated carbon with acidic groups].

    PubMed

    Li, Kun-Quan; Li, Ye; Zheng, Zheng; Zhang, Yu-Xuan

    2013-06-01

    Mesoporous activated carbons containing acidic groups were prepared with cotton stalk based fiber as raw materials and H3PO4 as activating agent by one step carbonization method. Effects of impregnation ratio, carbonization temperature and heat preservation time on the yield, elemental composition, oxygen-containing acid functional groups and adsorptive capacity of activated carbon were studied. The adsorption capacity of the prepared activated carbon AC-01 for p-nitroaniline and Pb(II) was studied, and the adsorption mechanism was also suggested according to the equilibrium experimental results. The maximum yield of activated carbons prepared from cotton stalk fiber reached 35.5% when the maximum mesoporous volume and BET surface area were 1.39 cm3 x g(-1) and 1 731 m2 x g(-1), respectively. The activated carbon AC-01 prepared under a H3 PO4/precursor ratio of 3:2 and activated at 900 degrees C for 90 min had a total pore volume of 1.02 cm3 x g(-1), a micoporous ratio of 31%, and a mesoporous ratio of 65%. The pore diameter of the mesoporous activated carbon was mainly distributed in the range of 2-5 nm. The Langmuir maximum adsorption capacities of Pb(II) and p-nitroaniline on cotton stalk fiber activated carbon were 123 mg x g(-1) and 427 mg x g(-1), respectively, which were both higher than those for commercial activated carbon fiber ACF-CK. The equilibrium adsorption experimental data showed that mesopore and oxygen-containing acid functional groups played an important role in the adsorption.

  5. Hydrogen adsorption on functionalized nanoporous activated carbons.

    PubMed

    Zhao, X B; Xiao, B; Fletcher, A J; Thomas, K M

    2005-05-12

    There is considerable interest in hydrogen adsorption on carbon nanotubes and porous carbons as a method of storage for transport and related energy applications. This investigation has involved a systematic investigation of the role of functional groups and porous structure characteristics in determining the hydrogen adsorption characteristics of porous carbons. Suites of carbons were prepared with a wide range of nitrogen and oxygen contents and types of functional groups to investigate their effect on hydrogen adsorption. The porous structures of the carbons were characterized by nitrogen (77 K) and carbon dioxide (273 K) adsorption methods. Hydrogen adsorption isotherms were studied at 77 K and pressure up to 100 kPa. All the isotherms were Type I in the IUPAC classification scheme. Hydrogen isobars indicated that the adsorption of hydrogen is very temperature dependent with little or no hydrogen adsorption above 195 K. The isosteric enthalpies of adsorption at zero surface coverage were obtained using a virial equation, while the values at various surface coverages were obtained from the van't Hoff isochore. The values were in the range 3.9-5.2 kJ mol(-1) for the carbons studied. The thermodynamics of the adsorption process are discussed in relation to temperature limitations for hydrogen storage applications. The maximum amounts of hydrogen adsorbed correlated with the micropore volume obtained from extrapolation of the Dubinin-Radushkevich equation for carbon dioxide adsorption. Functional groups have a small detrimental effect on hydrogen adsorption, and this is related to decreased adsorbate-adsorbent and increased adsorbate-adsorbate interactions.

  6. Corn stalks char from fast pyrolysis as precursor material for preparation of activated carbon in fluidized bed reactor.

    PubMed

    Wang, Zhiqi; Wu, Jingli; He, Tao; Wu, Jinhu

    2014-09-01

    Corn stalks char from fast pyrolysis was activated by physical and chemical activation process in a fluidized bed reactor. The structure and morphology of the carbons were characterized by N2 adsorption and SEM. Effects of activation time and activation agents on the structure of activation carbon were investigated. The physically activated carbons with CO2 have BET specific surface area up to 880 m(2)/g, and exhibit microporous structure. The chemically activated carbons with H3PO4 have BET specific surface area up to 600 m(2)/g, and exhibit mesoporous structure. The surface morphology shows that physically activated carbons exhibit fibrous like structure in nature with long ridges, resembling parallel lines. Whereas chemically activated carbons have cross-interconnected smooth open pores without the fibrous like structure.

  7. HATS-2b: A transiting extrasolar planet orbiting a K-type star showing starspot activity

    NASA Astrophysics Data System (ADS)

    Mohler-Fischer, M.; Mancini, L.; Hartman, J. D.; Bakos, G. Á.; Penev, K.; Bayliss, D.; Jordán, A.; Csubry, Z.; Zhou, G.; Rabus, M.; Nikolov, N.; Brahm, R.; Espinoza, N.; Buchhave, L. A.; Béky, B.; Suc, V.; Csák, B.; Henning, T.; Wright, D. J.; Tinney, C. G.; Addison, B. C.; Schmidt, B.; Noyes, R. W.; Papp, I.; Lázár, J.; Sári, P.; Conroy, P.

    2013-10-01

    We report the discovery of HATS-2b, the second transiting extrasolar planet detected by the HATSouth survey. HATS-2b is moving on a circular orbit around a V = 13.6 mag, K-type dwarf star (GSC 6665-00236), at a separation of 0.0230 ± 0.0003 AU and with a period of 1.3541 days. The planetary parameters have been robustly determined using a simultaneous fit of the HATSouth, MPG/ESO 2.2 m/GROND, Faulkes Telescope South/Spectral transit photometry, and MPG/ESO 2.2 m/FEROS, Euler 1.2 m/CORALIE, AAT 3.9 m/CYCLOPS radial-velocity measurements. HATS-2b has a mass of 1.37 ± 0.16 MJ, a radius of 1.14 ± 0.03 RJ, and an equilibrium temperature of 1567 ± 30 K. The host star has a mass of 0.88 ± 0.04 M⊙ and a radius of 0.89 ± 0.02 R⊙, and it shows starspot activity. We characterized the stellar activity by analyzing two photometric follow-up transit light curves taken with the GROND instrument, both obtained simultaneously in four optical bands (covering the wavelength range of 3860-9520 Å). The two light curves contain anomalies compatible with starspots on the photosphere of the host star along the same transit chord. Tables of the individual photometric measurements are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/558/A55

  8. Total alkaloids of Rubus alceifolius Poir shows anti-angiogenic activity in vivo and in vitro.

    PubMed

    Zhao, Jinyan; Lin, Wei; Zhuang, Qunchuan; Zhong, Xiaoyong; Cao, Zhiyun; Hong, Zhenfeng; Peng, Jun

    2014-11-01

    Total alkaloids is an active ingredient of the natural plant Rubus alceifolius Poir, commonly used for the treatment of various cancers. Antitumor effects may be mediated through anti-angiogenic mechanisms. As such, the goal of the present study was to investigate and evaluate the effect of total alkaloids in Rubus alceifolius Poir (TARAP) on tumor angiogenesis and investigate the underlying molecular mechanisms of TARAP action in vivo and in vitro. A chick embryo chorioallantoic membrane (CAM) assay was used to assess angiogenesis in vivo. An MTT assay was performed to determine the viability of human umbilical vein endothelial cells (HUVECs) with and without treatment. Cell cycle progression of HUVECs was examined by FACS analysis with propidium iodide staining. HUVEC migration was determined using a scratch wound method. Tube formation of HUVECs was assessed with an ECMatrix gel system, and mRNA and protein expression of VEGF-A in both HUVECs and HepG2 human hepatocellular carcinoma cells were examined by RT-PCR and ELISA, respectively. Our results showed that TARAP inhibited angiogenesis in the CAM model in vivo and inhibited HUVEC proliferation via blocking cell cycle G1 to S progression in a dose- and time-dependent manners in vitro. Moreover, TARAP inhibited HUVEC migration and tube formation and downregulated mRNA and protein expression of VEGF-A in both HepG2 cells and HUVECs. Our findings suggest that the anti-angiogenic activity of TARAP may partly contribute to its antitumor properties and may be valuable for the treatment of diseases involving pathologic angiogenesis such as cancer.

  9. Select metal adsorption by activated carbon made from peanut shells.

    PubMed

    Wilson, Kermit; Yang, Hong; Seo, Chung W; Marshall, Wayne E

    2006-12-01

    Agricultural by-products, such as peanut shells, contribute large quantities of lignocellulosic waste to the environment each growing season; but few, if any, value-added uses exist for their disposal. The objective of this study was to convert peanut shells to activated carbons for use in adsorption of select metal ions, namely, cadmium (Cd2+), copper (Cu2+), lead (Pb2+), nickel (Ni2+) and zinc (Zn2+). Milled peanut shells were pyrolyzed in an inert atmosphere of nitrogen gas, and then activated with steam at different activation times. Following pyrolysis and activation, the carbons underwent air oxidation. The prepared carbons were evaluated either for adsorption efficiency or adsorption capacity; and these parameters were compared to the same parameters obtained from three commercial carbons, namely, DARCO 12x20, NORIT C GRAN and MINOTAUR. One of the peanut shell-based carbons had metal ion adsorption efficiencies greater than two of the three commercial carbons but somewhat less than but close to Minotaur. This study demonstrates that peanut shells can serve as a source for activated carbons with metal ion-removing potential and may serve as a replacement for coal-based commercial carbons in applications that warrant their use.

  10. Physical and chemical properties and adsorption type of activated carbon prepared from plum kernels by NaOH activation.

    PubMed

    Tseng, Ru-Ling

    2007-08-25

    Activated carbon was prepared from plum kernels by NaOH activation at six different NaOH/char ratios. The physical properties including the BET surface area, the total pore volume, the micropore ratio, the pore diameter, the burn-off, and the scanning electron microscope (SEM) observation as well as the chemical properties, namely elemental analysis and temperature programmed desorption (TPD), were measured. The results revealed a two-stage activation process: stage 1 activated carbons were obtained at NaOH/char ratios of 0-1, surface pyrolysis being the main reaction; stage 2 activated carbons were obtained at NaOH/char ratios of 2-4, etching and swelling being the main reactions. The physical properties of stage 2 activated carbons were similar, and specific area was from 1478 to 1887m(2)g(-1). The results of reaction mechanism of NaOH activation revealed that it was apparently because of the loss ratio of elements C, H, and O in the activated carbon, and the variations in the surface functional groups and the physical properties. The adsorption of the above activated carbons on phenol and three kinds of dyes (MB, BB1, and AB74) were used for an isotherm equilibrium adsorption study. The data fitted the Langmuir isotherm equation. Various kinds of adsorbents showed different adsorption types; separation factor (R(L)) was used to determine the level of favorability of the adsorption type. In this work, activated carbons prepared by NaOH activation were evaluated in terms of their physical properties, chemical properties, and adsorption type; and activated carbon PKN2 was found to have most application potential.

  11. Alpha casein micelles show not only molecular chaperone-like aggregation inhibition properties but also protein refolding activity from the denatured state.

    PubMed

    Sakono, Masafumi; Motomura, Konomi; Maruyama, Tatsuo; Kamiya, Noriho; Goto, Masahiro

    2011-01-07

    Casein micelles are a major component of milk proteins. It is well known that casein micelles show chaperone-like activity such as inhibition of protein aggregation and stabilization of proteins. In this study, it was revealed that casein micelles also possess a high refolding activity for denatured proteins. A buffer containing caseins exhibited higher refolding activity for denatured bovine carbonic anhydrase than buffers including other proteins. In particular, a buffer containing α-casein showed about a twofold higher refolding activity compared with absence of α-casein. Casein properties of surface hydrophobicity, a flexible structure and assembly formation are thought to contribute to this high refolding activity. Our results indicate that casein micelles stabilize milk proteins by both chaperone-like activity and refolding properties.

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

    PubMed

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

    2010-01-01

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

  13. Effect of calcium on adsorption capacity of powdered activated carbon.

    PubMed

    Li, Gang; Shang, Junteng; Wang, Ying; Li, Yansheng; Gao, Hong

    2013-12-01

    We investigated the effect of calcium ion on the adsorption of humic acid (HA) (as a target pollutant) by powered activated carbon. The HA adsorption isotherms at different pH and kinetics of two different solutions including HA alone and HA doped Ca(2+), were performed. It was showed that the adsorption capacity of powdered activated carbon (PAC) for HA was markedly enhanced when Ca(2+) was doped into HA. Also, HA and Ca(2+) taken as nitrate were tested on the uptake of each other respectively and it was showed that the adsorbed amounts of both of them were significantly promoted when HA and calcium co-existed. Furthermore, the adsorbed amount of HA slightly decreased with the increasing of Ca(2+) concentration, whereas the amount of calcium increased with the increasing of HA concentration, but all above the amounts without addition. Finally, the change of pH before and after adsorption process is studied. In the two different solutions including HA alone and HA doped Ca(2+), pH had a small rise, but the extent of pH of later solution was bigger.

  14. Observations of net soil exchange of CO2 in a dryland show experimental warming increases carbon losses in biocrust soils

    USGS Publications Warehouse

    Darrouzet-Nardi, Anthony N.; Reed, Sasha C.; Grote, Ed; Belnap, Jayne

    2015-01-01

    Many arid and semiarid ecosystems have soils covered with well-developed biological soil crust communities (biocrusts) made up of mosses, lichens, cyanobacteria, and heterotrophs living at the soil surface. These communities are a fundamental component of dryland ecosystems, and are critical to dryland carbon (C) cycling. To examine the effects of warming temperatures on soil C balance in a dryland ecosystem, we used infrared heaters to warm biocrust-dominated soils to 2 °C above control conditions at a field site on the Colorado Plateau, USA. We monitored net soil exchange (NSE) of CO2 every hour for 21 months using automated flux chambers (5 control and 5 warmed chambers), which included the CO2 fluxes of the biocrusts and the soil beneath them. We observed measurable photosynthesis in biocrust soils on 12 % of measurement days, which correlated well with precipitation events and soil wet-up. These days included several snow events, providing what we believe to be the first evidence of substantial photosynthesis underneath snow by biocrust organisms in drylands. Overall, biocrust soils in both control and warmed plots were net CO2 sources to the atmosphere, with control plots losing 62 ± 8 g C m−2 (mean ± SE) over the first year of measurement and warmed plots losing 74 ± 9 g C m−2. Between control and warmed plots, the difference in soil C loss was uncertain over the course of the entire year due to large and variable rates in spring, but on days during which soils were wet and crusts were actively photosynthesizing, biocrusts that were warmed by 2 °C had a substantially more negative C balance (i.e., biocrust soils took up less C and/or lost more C in warmed plots). Taken together, our data suggest a substantial risk of increased C loss from biocrust soils with higher future temperatures, and highlight a robust capacity to predict CO2 exchange in biocrust soils using easily measured environmental parameters.

  15. Characterization and Conductivity Behavior of Magnetic Activated Carbon (MAC) from FeCl2.4H2O-Containing Carbon

    NASA Astrophysics Data System (ADS)

    Aripin, Department Of Physics, Faculty Of Mathematics; Natural Science, Haluoleo University, Kampus Bumi Tridharma Anduonohu Kendari 93232 Indonesia

    2007-05-01

    Activated carbons (AC) and magnetic-containing activated carbons (MAC) have been synthesized using coconut shells as carbon sources and FeCl2.4H2O as magnetic precursor. The samples were characterized by nitrogen sorption, XRD, and FTIR. The BET surface area and total pore volume of MAC increase as the temperature increased. AC has XRD peaks, which evidences an amorphous carbon framework and MAC shows that this material consists of an organized carbon with the nanocrystalline magnetite embedded in its structure. The FTIR spectrum of MAC shows that carboxyl groups decreased as the temperature increased. Absorption bands of MAC shows the stretching and torsional vibration modes of the magnetite Fe-O bond in tetrahedral and octahedral sites, respectively. The electrical conductivity studies showed that conductivity of MAC is more than the AC due to structural properties of carbons exists on a framework containing metal structures.

  16. Using analogy role-play activity in an undergraduate biology classroom to show central dogma revision.

    PubMed

    Takemura, Masaharu; Kurabayashi, Mario

    2014-01-01

    For the study of biology in an undergraduate classroom, a classroom exercise was developed: an analogy role-play to learn mechanisms of gene transcription and protein translation (central dogma). To develop the central dogma role-play exercise, we made DNA and mRNA using paper sheets, tRNA using a wire dress hanger, and amino acids using Lego® blocks (Lego System A/S, Denmark). Students were studying in the course of mathematics, physics, or chemistry, so biology was not among their usual studies. In this exercise, students perform the central dogma role-play and respectively act out nuclear matrix proteins, a transcription factor, an RNA polymerase II, an mRNA transport protein, nuclear pore proteins, a large ribosomal subunit, a small ribosomal subunit, and several amino-acyl tRNA synthetases. Questionnaire results obtained after the activity show that this central dogma role-play analogy holds student interest in the practical molecular biological processes of transcription and translation.

  17. Novel Peptides from Skins of Amphibians Showed Broad-Spectrum Antimicrobial Activities.

    PubMed

    Wang, Ying; Zhang, Yue; Lee, Wen-Hui; Yang, Xinwang; Zhang, Yun

    2016-03-01

    Peptide agents are often considered as potential biomaterials for developing new drugs that can overcome the rising resistance of pathogenic micro-organisms to classic antibiotic treatments. One key source of peptide agents is amphibian skin, as they provide a great deal of naturally occurring antimicrobial peptide (AMP) templates awaiting further exploitation and utilization. In this study, 12 novel AMPs from the skins of 3 ranid frogs, Rana limnocharis, R. exilispinosa, and Amolops afghanus, were identified using a 5' PCR primer. A total of 11 AMPs exhibited similarities with currently known AMP families, including brevinin-1, brevinin-2, esculentin-1, and nigrocin, besides, one AMP, named as Limnochariin, represented a novel AMP family. All 12 AMPs contain a C-terminus cyclic motif and most of them show obvious antimicrobial activities against 18 standard and clinically isolated strains of bacteria, including 4 Gram-positive bacteria, 11 Gram-negative bacteria, and 3 fungus. These findings provide helpful insight that will be useful in the design of anti-infective peptide agents.

  18. Grafting of activated carbon cloths for selective adsorption

    NASA Astrophysics Data System (ADS)

    Gineys, M.; Benoit, R.; Cohaut, N.; Béguin, F.; Delpeux-Ouldriane, S.

    2016-05-01

    Chemical functionalization of an activated carbon cloth with 3-aminophthalic acid and 4-aminobenzoic acid groups by the in situ formation of the corresponding diazonium salt in aqueous acidic solution is reported. The nature and amount of selected functions on an activated carbon surface, in particular the grafted density, were determined by potentiometric titration, elemental analysis and X-ray photoelectron spectroscopy (XPS). The nanotextural properties of the modified carbon were explored by gas adsorption. Functionalized activated carbon cloth was obtained at a discrete grafting level while preserving interesting textural properties and a large porous volume. Finally, the grafting homogeneity of the carbon surface and the nature of the chemical bonding were investigated using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) technique.

  19. 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.

  20. 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.

  1. [Vertical distribution of soil active carbon and soil organic carbon storage under different forest types in the Qinling Mountains].

    PubMed

    Wang, Di; Geng, Zeng-Chao; She, Diao; He, Wen-Xiang; Hou, Lin

    2014-06-01

    Adopting field investigation and indoor analysis methods, the distribution patterns of soil active carbon and soil carbon storage in the soil profiles of Quercus aliena var. acuteserrata (Matoutan Forest, I), Pinus tabuliformis (II), Pinus armandii (III), pine-oak mixed forest (IV), Picea asperata (V), and Quercus aliena var. acuteserrata (Xinjiashan Forest, VI) of Qinling Mountains were studied in August 2013. The results showed that soil organic carbon (SOC), microbial biomass carbon (MBC), dissolved organic carbon (DOC), and easily oxidizable carbon (EOC) decreased with the increase of soil depth along the different forest soil profiles. The SOC and DOC contents of different depths along the soil profiles of P. asperata and pine-oak mixed forest were higher than in the other studied forest soils, and the order of the mean SOC and DOC along the different soil profiles was V > IV > I > II > III > VI. The contents of soil MBC of the different forest soil profiles were 71.25-710.05 mg x kg(-1), with a content sequence of I > V > N > III > II > VI. The content of EOC along the whole soil profile of pine-oak mixed forest had a largest decline, and the order of the mean EOC was IV > V> I > II > III > VI. The sequence of soil organic carbon storage of the 0-60 cm soil layer was V > I >IV > III > VI > II. The MBC, DOC and EOC contents of the different forest soils were significanty correlated to each other. There was significant positive correlation among soil active carbon and TOC, TN. Meanwhile, there was no significant correlation between soil active carbon and other soil basic physicochemical properties.

  2. Is carbon sequestration on post mining sites driven by earthworm activity?

    NASA Astrophysics Data System (ADS)

    Frouz, J.; Pizl, V.

    2009-04-01

    Carbon storage was measured in seven types of forest (alder, oak, lime, willow-birch, pine, spruce and larch) about 30 years old developed in on e large post mining site as split plot design. The carbon storage in soil wary substantial and represent 10-100% of carbon storage in aboveground wood biomass. Carbon storage in soil do not show any correlation with litter input but correlate significantly and positively with earthworm abundance, and micromorphological traces of earthworm activity. Field and laboratory microcosm experiment showed that earthworm mediated soil mixing support carbon storage in soil. Detailed study of soil aggregates created by worms and other forces indicated that worm aggregates contain much larger content of POC. This indicate that soil bioturbation by earthworms may significantly increase carbon storage in soil.

  3. 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.

  4. Activated carbons from flax shive and cotton gin waste as environmental adsorbents for the chlorinated hydrocarbon trichloroethylene.

    PubMed

    Klasson, K Thomas; Wartelle, Lynda H; Lima, Isabel M; Marshall, Wayne E; Akin, Danny E

    2009-11-01

    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 to show that flax shive and cotton gin waste can serve as a precursor for activated carbon that can be used for adsorption of trichloroethylene (TCE) from both the liquid and gas phases. Testing was conducted on carbon activated with phosphoric acid or steam. The results show that activated carbon made from flax shive performed better than select commercial activated carbons, especially at higher TCE concentrations. The activation method employed had little effect on TCE adsorption in gas or vapor phase studies but liquid phase studies suggested that steam activation is slightly better than phosphoric acid activation. As expected, the capacity for the activated carbons depended on the fluid phase equilibrium concentration. At a fluid concentration of 2 mg of TCE/L of fluid, the capacity of the steam activated carbon made from flax shive was similar at 64 and 80 mg TCE/g of carbon for the vapor and liquid phases, respectively. Preliminary cost estimates suggest that the production costs of such carbons are $1.50 to $8.90 per kg, depending on activation method and precursor material; steam activation was significantly less expensive than phosphoric acid activation.

  5. 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.

  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. 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.

  8. Pressurized laboratory experiments show no stable carbon isotope fractionation of methane during gas hydrate dissolution and dissociation.

    PubMed

    Lapham, Laura L; Wilson, Rachel M; Chanton, Jeffrey P

    2012-01-15

    The stable carbon isotopic ratio of methane (δ(13)C-CH(4)) recovered from marine sediments containing gas hydrate is often used to infer the gas source and associated microbial processes. This is a powerful approach because of distinct isotopic fractionation patterns associated with methane production by biogenic and thermogenic pathways and microbial oxidation. However, isotope fractionations due to physical processes, such as hydrate dissolution, have not been fully evaluated. We have conducted experiments to determine if hydrate dissolution or dissociation (two distinct physical processes) results in isotopic fractionation. In a pressure chamber, hydrate was formed from a methane gas source at 2.5 MPa and 4 °C, well within the hydrate stability field. Following formation, the methane source was removed while maintaining the hydrate at the same pressure and temperature which stimulated hydrate dissolution. Over the duration of two dissolution experiments (each ~20-30 days), water and headspace samples were periodically collected and measured for methane concentrations and δ(13)C-CH(4) while the hydrate dissolved. For both experiments, the methane concentrations in the pressure chamber water and headspace increased over time, indicating that the hydrate was dissolving, but the δ(13)C-CH(4) values showed no significant trend and remained constant, within 0.5‰. This lack of isotope change over time indicates that there is no fractionation during hydrate dissolution. We also investigated previous findings that little isotopic fractionation occurs when the gas hydrate dissociates into gas bubbles and water due to the release of pressure. Over a 2.5 MPa pressure drop, the difference in the δ(13)C-CH(4) was <0.3‰. We have therefore confirmed that there is no isotope fractionation when the gas hydrate dissociates and demonstrated that there is no fractionation when the hydrate dissolves. Therefore, measured δ(13)C-CH(4) values near gas hydrates are not affected

  9. Syzyguim guineense Extracts Show Antioxidant Activities and Beneficial Activities on Oxidative Stress Induced by Ferric Chloride in the Liver Homogenate.

    PubMed

    Pieme, Constant Anatole; Ngoupayo, Joseph; Nkoulou, Claude Herve Khou-Kouz; Moukette, Bruno Moukette; Nono, Borgia Legrand Njinkio; Moor, Vicky Jocelyne Ama; Minkande, Jacqueline Ze; Ngogang, Jeanne Yonkeu

    2014-09-19

    The aim of this study was to determine the in vitro antioxidant activity, free radical scavenging property and the beneficial effects of extracts of various parts of Syzygium guineense in reducing oxidative stress damage in the liver. The effects of extracts on free radicals were determined on radicals DPPH, ABTS, NO and OH followed by the antioxidant properties using Ferric Reducing Antioxidant Power assay (FRAP) and hosphomolybdenum (PPMB). The phytochemical screening of these extracts was performed by determination of the phenolic content. The oxidative damage inhibition in the liver was determined by measuring malondialdehyde (MDA) as well as the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase. Overall, the bark extract of the ethanol/water or methanol showed the highest radical scavenging activities against DPPH, ABTS and OH radicals compared to the other extracts. This extract also contained the highest phenolic content implying the potential contribution of phenolic compounds towards the antioxidant activities. However, the methanol extract of the root demonstrated the highest protective effects of SOD and CAT against ferric chloride while the hydro-ethanol extract of the leaves exhibited the highest inhibitory effects on lipid peroxidation. These findings suggest that antioxidant properties of S. guineense extracts could be attributed to phenolic compounds revealed by phytochemical studies. Thus, the present results indicate clearly that the extracts of S. guineense possess antioxidant properties and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants. The antioxidant properties of the bark extract may thus sustain its various biological activities.

  10. Syzyguim guineense Extracts Show Antioxidant Activities and Beneficial Activities on Oxidative Stress Induced by Ferric Chloride in the Liver Homogenate

    PubMed Central

    Pieme, Constant Anatole; Ngoupayo, Joseph; Khou-Kouz Nkoulou, Claude Herve; Moukette Moukette, Bruno; Njinkio Nono, Borgia Legrand; Ama Moor, Vicky Jocelyne; Ze Minkande, Jacqueline; Yonkeu Ngogang, Jeanne

    2014-01-01

    The aim of this study was to determine the in vitro antioxidant activity, free radical scavenging property and the beneficial effects of extracts of various parts of Syzygium guineense in reducing oxidative stress damage in the liver. The effects of extracts on free radicals were determined on radicals DPPH, ABTS, NO and OH followed by the antioxidant properties using Ferric Reducing Antioxidant Power assay (FRAP) and hosphomolybdenum (PPMB). The phytochemical screening of these extracts was performed by determination of the phenolic content. The oxidative damage inhibition in the liver was determined by measuring malondialdehyde (MDA) as well as the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase. Overall, the bark extract of the ethanol/water or methanol showed the highest radical scavenging activities against DPPH, ABTS and OH radicals compared to the other extracts. This extract also contained the highest phenolic content implying the potential contribution of phenolic compounds towards the antioxidant activities. However, the methanol extract of the root demonstrated the highest protective effects of SOD and CAT against ferric chloride while the hydro-ethanol extract of the leaves exhibited the highest inhibitory effects on lipid peroxidation. These findings suggest that antioxidant properties of S. guineense extracts could be attributed to phenolic compounds revealed by phytochemical studies. Thus, the present results indicate clearly that the extracts of S. guineense possess antioxidant properties and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants. The antioxidant properties of the bark extract may thus sustain its various biological activities. PMID:26785075

  11. Imidazolium-Functionalized Carbon Nanohorns for the Conversion of Carbon Dioxide: Unprecedented Increase of Catalytic Activity after Recycling.

    PubMed

    Calabrese, Carla; Liotta, Leonarda F; Carbonell, Esther; Giacalone, Francesco; Gruttadauria, Michelangelo; Aprile, Carmela

    2016-11-29

    Six new hybrid materials composed of carbon nanohorns (CNHs) and highly cross-linked imidazolium salts were easily synthesized using a one-step procedure based on the radical oligomerization of bis-vinylimidazolium salts (bVImiX) in the presence of pristine CNHs. The hybrid materials were characterized and employed as the sole catalysts for the conversion of carbon dioxide into cyclic carbonate by reaction with epoxides. The solids displayed excellent turnover number and productivity. Moreover, four catalysts were investigated in recycling experiments. Two catalysts containing an octyl linker between the imidazolium units and a bromide or an iodide anion showed no loss in activity after three cycles. The other two catalysts containing a p-xylyl linker and a bromide anion and different CNHs/bVImiX ratios showed an unprecedented increase of activity after recycling.

  12. Mice lacking brain-type creatine kinase activity show defective thermoregulation

    PubMed Central

    Streijger, Femke; Pluk, Helma; Oerlemans, Frank; Beckers, Gaby; Bianco, Antonio C.; Ribeiro, Miriam O.; Wieringa, Bé; Van der Zee, Catharina E.E.M.

    2010-01-01

    The cytosolic brain-type creatine kinase and mitochondrial ubiquitous creatine kinase (CK-B and UbCKmit) are expressed during the prepubescent and adult period of mammalian life. These creatine kinase (CK) isoforms are present in neural cell types throughout the central and peripheral nervous system and in smooth muscle containing tissues, where they have an important role in cellular energy homeostasis. Here, we report on the coupling of CK activity to body temperature rhythm and adaptive thermoregulation in mice. With both brain-type CK isoforms being absent, the body temperature reproducibly drops ~1.0°C below normal during every morning (inactive) period in the daily cycle. Facultative non-shivering thermogenesis is also impaired, since CK−−/−− mice develop severe hypothermia during 24 h cold exposure. A relationship with fat metabolism was suggested because comparison of CK−−/−− mice with wildtype controls revealed decreased weight gain associated with less white and brown fat accumulation and smaller brown adipocytes. Also, circulating levels of glucose, triglycerides and leptin are reduced. Extensive physiological testing and uncoupling protein1 analysis showed, however, that the thermogenic problems are not due to abnormal responsiveness of brown adipocytes, since noradrenaline infusion produced a normal increase of body temperature. Moreover, we demonstrate that the cyclic drop in morning temperature is also not related to altered rhythmicity with reduced locomotion, diminished food intake or increased torpor sensitivity. Although several integral functions appear altered when CK is absent in the brain, combined findings point into the direction of inefficient neuronal transmission as the dominant factor in the thermoregulatory defect. PMID:19419668

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

    DOEpatents

    Schwarz, James A.; Noh, Joong S.; Agarwal, Rajiv K.

    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.

  14. 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

  15. Cold catalytic recovery of loaded activated carbon using iron oxide-based nanoparticles.

    PubMed

    Bach, Altai; Zelmanov, Grigory; Semiat, Raphael

    2008-01-01

    A novel approach for the recovery of spent activated carbon by an advanced oxidation process using iron oxide-based nanocatalysts was proposed and investigated. Model organic contaminants, such as ethylene glycol and phenol, were chosen for this study as water pollutants. It was shown that there are several advantages in using catalytic oxidation recovery of activated carbon with iron oxide-based nanocatalysts: low temperature reactivity of catalytic recovery without heating; and a relatively large number of adsorption-recovery cycles, without a reduction in the adsorptive properties of the virgin activated carbon or without a performance decrease from the first adsorption-recovery cycle of the new modified adsorptive properties of the activated carbon. The catalytic recovery takes place without ultraviolet light or any visible radiation sources. Results show a high efficiency of catalytic recovery of spent activated carbon using iron oxide-based nanocatalysts. A 97-99% efficiency of spent activated carbon catalytic regeneration was achieved under chosen conditions after 15-20 min of reaction. The process may be also considered as cold in situ recovery of active carbon.

  16. Desulphurization performance of TiO2-modified activated carbon by a one-step carbonization-activation method.

    PubMed

    Zhang, Chuanjun; Yang, Danni; Jiang, Xia; Jiang, Wenju

    2016-08-01

    In this study, TiO2 powder was used as the additive to directly blend with raw bituminous coal and coking coal for preparing modified activated carbon (Ti/AC) by one-step carbonization-activation method. The Ti/AC samples were prepared through blending with different ratios of TiO2 (0-12 wt%) and their desulphurization performance was evaluated. The results show that the desulphurization activity of all Ti/AC samples was higher than that of the blank one, and the highest breakthrough sulphur capacity was obtained at 200.55 mg/g C when the blending ratio of TiO2 was 6 wt%. The Brunauer-Emmett-Temer results show that the micropores were dominant in the Ti/AC samples, and their textual properties did not change evidently compared with the blank one. The X-ray photoelectron spectroscopy results show that the loaded TiO2 could influence the relative content of surface functional groups, with slightly higher content of π-π* transitions groups on the Ti/AC samples, and the relative contents of C=O and π-π* transitions groups decreased evidently after the desulphurization process. The X-ray diffraction results show that the anatase TiO2 and rutile TiO2 co-existed on the surface of the Ti/AC samples. After the desulphurization process, TiO2 phases did not change and Ti(SO4)2 was not observed on the Ti/AC samples, while sulphate was the main desulphurization product. It can be assumed that SO2 could be catalytically oxidized into SO3 by TiO2 indirectly, rather than TiO2 directly reacted with SO2 to Ti(SO4)2.

  17. 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.

  18. 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.

  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. [Influence of biological activated carbon dosage on landfill leachate treatment].

    PubMed

    Cui, Yan-Rui; Guo, Yan; Wu, Qing

    2014-08-01

    Effects of biological activated carbon (BAC) dosage on COD removal in landfill leachate treatment were compared. The COD removal efficiency of reactors with 0, 100 and 300 g activated carbon dosage per litre activated sludge was 12.9%, 19.6% and 27.7%, respectively. The results indicated that BAC improved the refractory organic matter removal efficiency and there was a positive correlation between COD removal efficiency and BAC dosage. The output of carbon dioxide after 8h of aeration in reactors was 109, 193 and 306 mg corresponding to the activated carbon dosages mentioned above, which indicated the amount of biodegradation and BAC dosage also had a positive correlation. The combination of adsorption and bioregeneration of BAC resulted in the positive correlation betweem organic matter removal efficiency and BAC dosage, and bioregeneration was the root cause for the microbial decomposition of refractory organics.

  1. 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.

  2. Cellulose: A review as natural, modified and activated carbon adsorbent.

    PubMed

    Suhas; Gupta, V K; Carrott, P J M; Singh, Randhir; Chaudhary, Monika; Kushwaha, Sarita

    2016-09-01

    Cellulose is a biodegradable, renewable, non-meltable polymer which is insoluble in most solvents due to hydrogen bonding and crystallinity. Natural cellulose shows lower adsorption capacity as compared to modified cellulose and its capacity can be enhanced by modification usually by chemicals. This review focuses on the utilization of cellulose as an adsorbent in natural/modified form or as a precursor for activated carbon (AC) for adsorbing substances from water. The literature revealed that cellulose can be a promising precursor for production of activated carbon with appreciable surface area (∼1300m(2)g(-1)) and total pore volume (∼0.6cm(3)g(-1)) and the surface area and pore volume varies with the cellulose content. Finally, the purpose of review is to report a few controversies and unresolved questions concerning the preparation/properties of ACs from cellulose and to make aware to readers that there is still considerable scope for future development, characterization and utilization of ACs from cellulose.

  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. 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

  5. Carbon-carbon bond cleavage in activation of the prodrug nabumetone.

    PubMed

    Varfaj, Fatbardha; Zulkifli, Siti N A; Park, Hyoung-Goo; Challinor, Victoria L; De Voss, James J; Ortiz de Montellano, Paul R

    2014-05-01

    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.

  6. 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.

  7. Activated carbon fiber composite material and method of making

    DOEpatents

    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.

  8. Activated carbon fiber composite material and method of making

    DOEpatents

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

    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.

  9. Differential Scanning Calorimetry (DSC) for the Analysis of Activated Carbon

    DTIC Science & Technology

    1991-10-01

    impregnation procedures . It is believed that Sutcliffe-Speakman is currently using coconut - shell as the carbon precursor (instead of the New Zealand coal...microstructure facilitate the adsorption process whereby all the undesirable materials are retained. For military deployment, the activated carbon is...AD-A245 899 H.P ’ l N dI dUenm / DIFFERENTIAL SCANNING CALORIMETRY (DSC) FOR THE ANALYSIS OF ACTIVATED CARBON (U) by S.H.C. a and L.E. Cameron DTIC x

  10. Production of activated carbon from rice husk Vietnam

    NASA Astrophysics Data System (ADS)

    Korobochkin, V. V.; Tu, N. V.; Hieu, N. M.

    2016-09-01

    This work is dedicated to the production of activated carbon from rice husk from Delta of the Red River in Viet Nam. At the first stage, carbonization of a rice husk was carried out to obtain material containing 43.1% carbon and 25 % silica with a specific surface area of 51.5 m2/g. After separating of silica (the second stage), the specific surface area of the product increased to 204 m2/g and the silica content decreased to 1.23% by weight as well. The most important stage in the formation of the porous structure of the material is the activation. The products with the high specific surface area in the range of 800-1345 m2/g were obtained by activation of carbonized product with water vapour or carbon dioxide at temperatures of 700 °C and 850 °C, with varying the flow rate of the activating agent and activation time. The best results were achieved by activation of carbon material with water vapour at the flow rate of 0.08 dm3/min per 500 g of material and the temperature of 850 °C.

  11. SYNTHESIS AND BIOLOGICAL ACTIVITY OF SULFUR COMPOUNDS SHOWING STRUCTURAL ANALOGY WITH COMBRETASTATIN A-4

    PubMed Central

    dos Santos, Edson dos A.; Prado, Paulo C.; de Carvalho, Wanderley R.; de Lima, Ricardo V.; Beatriz e, Adilson; de Lima, Dênis P.; Hamel, Ernest; Dyba, Marzena A.; Albuquerque, Sergio

    2013-01-01

    We extended our previous exploration of sulfur bridges as bioisosteric replacements for atoms forming the bridge between the aromatic rings of combretastatin A-4. Employing coupling reactions between 5-iodo-1,2,3-trimethoxybenzene and substituted thiols, followed by oxidation to sulfones with m-CPBA, different locations for attaching the sulfur atom to ring A through the synthesis of nine compounds were examined. Antitubulin activity was performed with electrophoretically homogenous bovine brain tubulin, and activity occurred with the 1,2,3-trimethoxy-4-[(4-methoxyphenyl)thio]benzene (12), while the other compounds were inactive. The compounds were also tested for leishmanicidal activity using promastigote forms of Leishmania braziliensis (MHOM/BR175/M2904), and the greatest activity was observed with 1,2,3-trimethoxy-4-(phenylthio)benzene (10) and 1,2,3-trimethoxy-4-[(4-methoxyphenyl) sulfinyl]benzene (15). PMID:23766547

  12. SYNTHESIS AND BIOLOGICAL ACTIVITY OF SULFUR COMPOUNDS SHOWING STRUCTURAL ANALOGY WITH COMBRETASTATIN A-4.

    PubMed

    Dos Santos, Edson Dos A; Prado, Paulo C; de Carvalho, Wanderley R; de Lima, Ricardo V; Beatriz E, Adilson; de Lima, Dênis P; Hamel, Ernest; Dyba, Marzena A; Albuquerque, Sergio

    2013-02-01

    We extended our previous exploration of sulfur bridges as bioisosteric replacements for atoms forming the bridge between the aromatic rings of combretastatin A-4. Employing coupling reactions between 5-iodo-1,2,3-trimethoxybenzene and substituted thiols, followed by oxidation to sulfones with m-CPBA, different locations for attaching the sulfur atom to ring A through the synthesis of nine compounds were examined. Antitubulin activity was performed with electrophoretically homogenous bovine brain tubulin, and activity occurred with the 1,2,3-trimethoxy-4-[(4-methoxyphenyl)thio]benzene (12), while the other compounds were inactive. The compounds were also tested for leishmanicidal activity using promastigote forms of Leishmania braziliensis (MHOM/BR175/M2904), and the greatest activity was observed with 1,2,3-trimethoxy-4-(phenylthio)benzene (10) and 1,2,3-trimethoxy-4-[(4-methoxyphenyl) sulfinyl]benzene (15).

  13. Separation of a toluene/ethanol mixture by pervaporation using active carbon-filled polymeric membranes

    SciTech Connect

    Duval, J.M. ); Folkers, B.; Mulder, M.H.V.; Smolders, C.A. ); Desgrandchamps, G. )

    1994-02-01

    In order to improve the separation properties of dense polymeric membranes toward a toluene/ethanol mixture, various active carbons and two types of zeolites were introduced into a thin polymeric film in order to form a heterogeneous membrane composed of solid particles surrounded by a polymer phase. Active carbons show a high adsorption selectivity for an aromatic compound over ethanol in the low concentration range of the aromatic component. Sorption and pervaporation experiments were carried out with a toluene/ethanol mixture, and they showed no improvement in selectivity and a decrease in flux for membranes filled with active carbons. For zeolite-filled membranes, both selectivity and flux decreased. A permeability model derived for heterogeneous systems was used. It confirmed that the carbon particles have a closed porous structure, allowing no transport from one side to the other, and that the zeolites have an ethanol selective permeation behavior. 21 refs., 7 figs., 6 tabs.

  14. Residue organic mixtures from drinking water show in vitro mutagenic and transforming activity.

    PubMed

    Loper, J C; Lang, D R; Schoeny, R S; Richmond, B B; Gallagher, P M; Smith, C C

    1978-01-01

    Indications of possible health effects of residue organics in drinking water have been sought using short-term tests of mutagenic and transforming activity. Ten percent or less of the total organic material in drinking water has been identified; the remainder is believed to include thousands of unknown nonvolatile compounds. Residual organics were concentrated from drinking water from representative U.S. cities by reverse osmosis followed by liquid-liquid extraction [yielding the reverse osmosis concentrate-organic extract (ROC-OE) fraction] and sorption-desorption on XAD-2 resin. Samples of these residue organics were provided by the Environmental Protection Agency for bioassay. They were examined for mutagenic activity by using Salmonella tester strains (primarily TA98 and TA100) and for transforming activity by using mouse fibroblasts (BALB/3T3 clone 1-13). City-specific patterns of dose-dependent bacterial mutagenesis and of bacterial toxicity were observed for these samples and for subfractions generated by sequential extractions with hexane, ethyl ether, and acetone. Mutagenic effects were essentially independent of a microsome activation system prepared from liver of Aroclor 1254-induced rats. On the basis of strain-specific effects in mutagenesis and differential distributions of mutagenic activity during liquid-liquid extraction, at least some of the active compounds are thought to be acidic, frameshift mutagens. The ROC-OE fraction of a New Orleans sample transformed BALB/3T3 cells in replicate experiments. By comparison with the bacterial mutagenesis data, cell transformation is a relatively sensitive method for detecting possible mutagenic and carcinogenic activity in this sample. The appropriateness of these systems for the assay of complex mixtures and the degree to which reverse osmosis concentrates contain the unaltered organic compounds in the original samples are discussed.

  15. 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.

  16. Effect of commercial activated carbons in sulfur cathodes on the electrochemical properties of lithium/sulfur batteries

    SciTech Connect

    Park, Jin-Woo; Kim, Icpyo; Kim, Ki-Won; Nam, Tae-Hyun; Cho, Kwon-Koo; Ahn, Jou-Hyeon; Ryu, Ho-Suk; Ahn, Hyo-Jun

    2016-10-15

    Highlights: • The sulfur/activated carbon composite is fabricated using commercial activated carbons. • The sulfur/activated carbon composite with coal shows the best performance. • The Li/S battery has capacities of 1240 mAh g{sup −1} at 1 C and 567 mAh g{sup −1} at 10 C. - Abstract: We prepared sulfur/active carbon composites via a simple solution-based process using the following commercial activated carbon-based materials: coal, coconut shells, and sawdust. Although elemental sulfur was not detected in any of the sulfur/activated carbon composites based on Thermogravimetric analysis, X-ray diffraction, and Raman spectroscopy, Energy-dispersive X-ray spectroscopy results confirmed its presence in the activated carbon. These results indicate that sulfur was successfully impregnated in the activated carbon and that all of the activated carbons acted as sulfur reservoirs. The sulfur/activated carbon composite cathode using coal exhibited the highest discharge capacity and best rate capability. The first discharge capacity at 1 C (1.672 A g{sup −1}) was 1240 mAh g{sup −1}, and a large reversible capacity of 567 mAh g{sup −1} was observed at 10 C (16.72 A g{sup −1}).

  17. Electroadsorption of Arsenic from natural water in granular activated carbon

    NASA Astrophysics Data System (ADS)

    Beralus, Jean-Mackson; Ruiz Rosas, Ramiro; Cazorla-Amoros, Diego; Morallon, Emilia

    2014-11-01

    The adsorption and electroadsorption of arsenic from a natural water has been studied in a filter-press electrochemical cell using a commercial granular activated carbon as adsorbent and Pt/Ti and graphite as electrodes. A significant reduction of the arsenic concentration is achieved when current is imposed between the electrodes, especially when the activated carbon was located in the vicinity of the anode. This enhancement can be explained in terms of the presence of electrostatic interactions between the polarized carbon surface and the arsenic ions, and changes in the distribution of most stable species of arsenic in solution due to As(III) to As(V) oxidation. In summary, electrochemical adsorption on a filter press cell can be used for enhancement the arsenic remediation with activated carbon in the treatment of a real groundwater.

  18. Performance of Spent Mushroom Farming Waste (SMFW) Activated Carbon for Ni (II) Removal

    NASA Astrophysics Data System (ADS)

    Desa, N. S. Md; Ghani, Z. Ab; Talib, S. Abdul; Tay, C. C.

    2016-07-01

    The feasibility of a low cost agricultural waste of spent mushroom farming waste (SMFW) activated carbon for Ni(II) removal was investigated. The batch adsorption experiments of adsorbent dosage, pH, contact time, metal concentration, and temperature were determined. The samples were shaken at 125 rpm, filtered and analyzed using ICP-OES. The fifty percent of Ni(II) removal was obtained at 0.63 g of adsorbent dosage, pH 5-6 (unadjusted), 60 min contact time, 50 mg/L Ni(II) concentration and 25 °C temperature. The evaluated SMFW activated carbon showed the highest performance on Ni(II) removal compared to commercial Amberlite IRC86 resin and zeolite NK3. The result indicated that SMFW activated carbon is a high potential cation exchange adsorbent and suitable for adsorption process for metal removal. The obtained results contribute toward application of developed SMFW activated carbon in industrial pilot study.

  19. The activation characteristics of the decomposition of H2O2 on palladium-carbon catalysts

    NASA Astrophysics Data System (ADS)

    Lapko, V. F.; Gerasimyuk, I. P.; Kuts', V. S.; Tarasenko, Yu. A.

    2010-06-01

    The kinetics of catalytic decomposition of H2O2 on palladium-carbon catalysts with various deposited metal distributions in carrier (active carbon) porous granules was studied. The activation parameters ( E a and A 0) of the process were calculated by the Arrhenius equation. A determining factor for the catalytic process was found to be the entropy factor ( A 0), which characterized the formation and dissociation of activated transition complexes. A quantum-chemical study of the electronic structure of palladium-carbon catalysts showed the occurrence of electron density transfer from the carbon matrix to metal clusters and collectivization of their electronic systems. This increased the donor-acceptor ability of the synthesized materials and, as a consequence, their catalytic activity.

  20. Metallic three-coordinated carbon networks with eight-membered rings showing high density of states at the Fermi level.

    PubMed

    Noda, Yusuke; Ono, Shota; Ohno, Kaoru

    2014-04-21

    Using a density functional method to study the electronic structure of various three-coordinated sp(2) carbon nanostructures, we find that the presence of an eight-membered ring adjoined to two five-membered rings in a unit cell brings about the simultaneous occurrence of flat and dispersive bands, quite similar to the band structure of precious metals. These bands are parts of an anisotropic Dirac cone tilted from an isotropic one. We reveal that in-phase and out-of-phase oscillations in the sign of the phase of the Kohn-Sham orbital contribute to the appearance of the unique band structures.

  1. Graphene as conductive additives in binderless activated carbon electrodes for power enhancement of supercapacitor

    NASA Astrophysics Data System (ADS)

    Nor, N. S. M.; Deraman, M.; Suleman, M.; Norizam, M. D. M.; Basri, N. H.; Sazali, N. E. S.; Hamdan, E.; Hanappi, M. F. Y. M.; Tajuddin, N. S. M.; Othman, M. A. R.; Shamsudin, S. A.; Omar, R.

    2016-11-01

    Carbon based supercapacitor electrodes from composite of binderless activated carbon and graphene as a conductive additive were fabricated with various amount of graphene (0, 2, 4, 6, 8 and 10 wt%). Graphene was mixed in self-adhesive carbon grains produced from pre-carbonized powder derived from fibers of oil palm empty fruit bunches and converted into green monoliths (GMs). The GMs were carbonized (N2) and activated (CO2) to produce activated carbon monoliths (ACMs) electrodes. Porosity characterizations by nitrogen adsorption-desorption isotherm method shows that the pore characteristics of the ACMs are influenced by the graphene additive. The results of galvanostatic charge-discharge tests carried out on the supercapacitor cells fabricated using these electrodes shows that the addition of graphene additive (even in small amount) decreases the equivalent series resistance and enhances the specific power of the cells but significantly lowers the specific capacitance. The supercapacitor cell constructed with the electrode containing 4 wt % of graphene offers the maximum power (175 W kg-1) which corresponds to an improvement of 55%. These results demonstrate that the addition of graphene as conductive additive in activated carbon electrodes can enhance the specific power of the supercapacitor.

  2. [Quickly enrichment of carbon in wastewater by activated sludge].

    PubMed

    Liu, Hong-Bo; Zhao, Fang; Wen, Xiang-Hua

    2011-10-01

    Pilot tests were carried out to investigate the absorption characteristics of the carbon source in urban wastewater by activated sludge and to analyze the carbon release from the carbon absorbed activated sludge in the settling process. The results indicated that carbon in wastewater could be quickly enriched by activated sludge. The absorption process of indissolvable organic matter could be finished as shortly as less than 10 min, while the absorption process of the dissolved organic matter was relatively slow and should consume up about 30 min. Moreover, carbon release was observed in the settling process of enriched sludge. In the period of 30-100 min, the release amount of total COD (TCOD) was 11.44 mg x g(-1), while in the period of 60-150 min, the release amount of dissolved COD (SCOD) was 6.24 mg x g(-1). Furthermore, based on the results of the bench-scale tests, a pilot-scale plant was built to investigate the absorption of carbon, nitrogen and phosphorus by activated sludge and the settleability of enriched sludge. The results indicated that under continuously operation mode, 60% of COD, 75% of TP and 10% of TN in the wastewater could be removed by the absorption of activated sludge, and the enriched sludge with SVI of 34.2 mL x g(-1) presented good settleability. Carbon enrichment by activated sludge could not only reclaim the carbon source in wastewater, but also reduce the loading of organic matter and give low C/N for the following nitrification unit and improving the nitrification efficiency.

  3. Water Works: A Great Show on Earth. Classroom Activities for Third and Fourth Grades.

    ERIC Educational Resources Information Center

    McClure, Judy; Clark, Neil

    This curriculum guide is divided into five lessons, each containing several activities that reflect the natural path of inquiry that third or fourth grade students might take in considering the water that arrives in their bathroom sinks each morning. Starting from the familiar faucet, the students are encouraged to reflect on their own habits and…

  4. Systematic Review Shows Only Few Reliable Studies of Physical Activity Intervention in Adolescents

    PubMed Central

    Soares, Nara Michelle Moura; Leão, Arley Santos; Santos, Josivan Rosa; Monteiro, Glauber Rocha; dos Santos, Jorge Rollemberg; Thomazzi, Sara Maria; Silva, Roberto Jerônimo dos Santos

    2014-01-01

    Introduction. Several studies have pointed to the high prevalence of low levels of physical activity in adolescents, suggesting the need for more effective interventions for this group. The aim of this study was to present evidence of intervention programs for efficacy of physical activity for adolescents. Methods. Surveys in PubMed, SportDiscus, LiLacs, and SciELO databases were conducted using keywords to identify population, intervention, and outcome, as well as DeCS and MeSH terms in English, Portuguese, and Spanish, whenever appropriate. The review included observational studies with minimal intervention of six months, minimum sample size of 100 adolescents, written in any language, and those who have reached STROBE score greater than 70%. Results. Only seven studies met all inclusion criteria. Of these, five were pre- and postintervention and two had n > 2000 participants. Interventions were of several types, durations, and strategies for physical activity implementation. Behavior change was assessed in 43% of studies and three reported success in some way. Conclusion. Due to heterogeneity in their contents and methodologies, as well as the lack of jobs that accompany adolescents after the intervention period, one cannot draw conclusions about the actual effects of the intervention programs of physical activity on the behavior of young people. PMID:25152903

  5. Activated carbon fiber for heterogeneous activation of persulfate: implication for the decolorization of azo dye.

    PubMed

    Chen, Jiabin; Hong, Wei; Huang, Tianyin; Zhang, Liming; Li, Wenwei; Wang, Ying

    2016-09-01

    Activated carbon fiber (ACF) was used as a green catalyst to activate persulfate (PS) for oxidative decolorization of azo dye. ACF demonstrated a higher activity than activated carbon (AC) to activate PS to decolorize Orange G (OG). The decolorization efficiency of OG increased as ACF loading, PS dosage, and temperature increased. OG decolorization followed a pseudo first-order kinetics, and the activation energy was 40.902 kJ/mol. pH had no apparent effect on OG decolorization. Radical quenching experiments with various radical scavengers (e.g., alcohols, phenol) showed that radical-induced decolorization of OG took place on the surface of ACF, and both SO4 (·-) and HO· were responsible for OG decolorization. The impact of inorganic salts was also evaluated because they are important compositions of dye wastewater. Cl(-) and SO4 (2-) exhibited a promoting effect on OG decolorization, and the accelerating rate increased with elevating dosage of ions. Addition of Cl(-) and SO4 (2-) could increase the adsorption of OG on ACF surface, thus favorable for OG decolorization caused by the surface-bound SO4 (·-) and HO·. Conversely, HCO3 (-) and humic acid (HA) slightly inhibited OG decolorization. The azo band and naphthalene ring on OG were remarkably destructed to other intermediates and finally mineralized to CO2 and H2O.

  6. 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.

  7. 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 π-electron energy to investigate the role of π-π 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

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

    PubMed

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

    2012-07-27

    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 π-electron energy to investigate the role of π-π 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

  9. SU-E-J-144: Low Activity Studies of Carbon 11 Activation Via GATE Monte Carlo

    SciTech Connect

    Elmekawy, A; Ewell, L; Butuceanu, C; Qu, L

    2015-06-15

    Purpose: To investigate the behavior of a Monte Carlo simulation code with low levels of activity (∼1,000Bq). Such activity levels are expected from phantoms and patients activated via a proton therapy beam. Methods: Three different ranges for a therapeutic proton radiation beam were examined in a Monte Carlo simulation code: 13.5, 17.0 and 21.0cm. For each range, the decay of an equivalent length{sup 11}C source and additional sources of length plus or minus one cm was studied in a benchmark PET simulation for activities of 1000, 2000 and 3000Bq. The ranges were chosen to coincide with a previous activation study, and the activities were chosen to coincide with the approximate level of isotope creation expected in a phantom or patient irradiated by a therapeutic proton beam. The GATE 7.0 simulation was completed on a cluster node, running Scientific Linux Carbon 6 (Red Hat©). The resulting Monte Carlo data were investigated with the ROOT (CERN) analysis tool. The half-life of{sup 11}C was extracted via a histogram fit to the number of simulated PET events vs. time. Results: The average slope of the deviation of the extracted carbon half life from the expected/nominal value vs. activity showed a generally positive value. This was unexpected, as the deviation should, in principal, decrease with increased activity and lower statistical uncertainty. Conclusion: For activity levels on the order of 1,000Bq, the behavior of a benchmark PET test was somewhat unexpected. It is important to be aware of the limitations of low activity PET images, and low activity Monte Carlo simulations. This work was funded in part by the Philips corporation.

  10. Adsorption-desorption characteristics of phenol and reactive dyes from aqueous solution on mesoporous activated carbon prepared from waste tires.

    PubMed

    Tanthapanichakoon, W; Ariyadejwanich, P; Japthong, P; Nakagawa, K; Mukai, S R; Tamon, H

    2005-04-01

    Liquid-phase adsorption-desorption characteristics and ethanol regeneration efficiency of an activated carbon prepared from waste tires and a commercial activated carbon were investigated. Water vapor adsorption experiments reveal that both activated carbons showed hydrophobic surface characteristics. Adsorption experiments reveal that the prepared activated carbon possessed comparable phenol adsorption capacity as the commercial one but clearly larger adsorption capacity of two reactive dyes, Black 5 and Red 31. It was ascertained that the prepared activated carbon exhibited less irreversible adsorption of phenol and the two dyes than its commercial counterpart. Moreover, ethanol regeneration efficiency of the prepared AC saturated with either dye was higher than that of the commercial AC. Because of its superior liquid-phase adsorption-desorption characteristics as well as higher ethanol regeneration efficiency, the prepared activated carbon is more suitable for wastewater treatment, especially for adsorbing similarly bulky adsorbates.

  11. Field-scale reduction of PCB bioavailability with activated carbon amendment to river sediments.

    PubMed

    Beckingham, Barbara; Ghosh, Upal

    2011-12-15

    Remediation of contaminated sediments remains a technological challenge because traditional approaches do not always achieve risk reduction goals for human health and ecosystem protection and can even be destructive for natural resources. Recent work has shown that uptake of persistent organic pollutants such as polychlorinated biphenyls (PCBs) in the food web is strongly influenced by the nature of contaminant binding, especially to black carbon surfaces in sediments. We demonstrate for the first time in a contaminated river that application of activated carbon to sediments in the field reduces biouptake of PCBs in benthic organisms. After treatment with activated carbon applied at a dose similar to the native organic carbon of sediment, bioaccumulation in freshwater oligochaete worms was reduced compared to preamendment conditions by 69 to 99%, and concentrations of PCBs in water at equilibrium with the sediment were reduced by greater than 93% at all treatment sites for up to three years of monitoring. By comparing measured reductions in bioaccumulation of tetra- and penta-chlorinated PCB congeners resulting from field application of activated carbon to a laboratory study where PCBs were preloaded onto activated carbon, it is evident that equilibrium sorption had not been achieved in the field. Although other remedies may be appropriate for some highly contaminated sites, we show through this pilot study that PCB exposure from moderately contaminated river sediments may be managed effectively through activated carbon amendment in sediments.

  12. A novel solubility-enhanced curcumin formulation showing stability and maintenance of anticancer activity.

    PubMed

    Zhang, Fang; Koh, Gar Yee; Jeansonne, Duane P; Hollingsworth, Javoris; Russo, Paul S; Vicente, Graca; Stout, Rhett W; Liu, Zhijun

    2011-07-01

    Curcumin (CUR) is an active food compound, but its insolubility and instability in water contributes to low bioavailability. In this study, the solubility of CUR was enhanced by utilizing the solubilizing properties of rubusoside (RUB). The solubility of CUR in water increased linearly from 61 μg/mL to 2.318 mg/mL in the presence of RUB ranging from 1% to 10% (w/v). Dynamic light scattering and transmission electron microscopy studies found that CUR and RUB formed CUR-RUB nanoparticle (∼8 nm) complexes. The RUB-solubilized CUR was stable in physiological conditions and did not precipitate when diluted or degrade when spray-dried to a completely reconstitutable powder. Furthermore, cell viability assays demonstrated the efficacy of RUB-solubilized CUR against human colon, breast, and pancreatic cancer cell lines. The development of this new solubilized, stable, and biologically active CUR formulation lays the foundation for future bioavailability improvement.

  13. Arginine kinase shows nucleoside diphosphate kinase-like activity toward deoxythymidine diphosphate.

    PubMed

    Lopez-Zavala, Alonso A; Sotelo-Mundo, Rogerio R; Hernandez-Flores, Jose M; Lugo-Sanchez, Maria E; Sugich-Miranda, Rocio; Garcia-Orozco, Karina D

    2016-06-01

    Arginine kinase (AK) (ATP: L-arginine phosphotransferase, E.C. 2.7.3.3) catalyzes the reversible transfer of ATP γ-phosphate group to L-arginine to synthetize phospho-arginine as a high-energy storage. Previous studies suggest additional roles for AK in cellular processes. Since AK is found only in invertebrates and it is homologous to creatine kinase from vertebrates, the objective of this work was to demonstrate nucleoside diphosphate kinase-like activity for shrimp AK. For this, AK from marine shrimp Litopenaeus vannamei (LvAK) was purified and its activity was assayed for phosphorylation of TDP using ATP as phosphate donor. Moreover, by using high-pressure liquid chromatography (HPLC) the phosphate transfer reaction was followed. Also, LvAK tryptophan fluorescence emission changes were detected by dTDP titration, suggesting that the hydrophobic environment of Trp 221, which is located in the top of the active site, is perturbed upon dTDP binding. The kinetic constants for both substrates Arg and dTDP were calculated by isothermal titration calorimetry (ITC). Besides, docking calculations suggested that dTDP could bind LvAK in the same cavity where ATP bind, and LvAK basic residues (Arg124, 126 and 309) stabilize the dTDP phosphate groups and the pyrimidine base interact with His284 and Ser122. These results suggest that LvAK bind and phosphorylate dTDP being ATP the phosphate donor, thus describing a novel alternate nucleoside diphosphate kinase-like activity for this enzyme.

  14. Identification of MET and SRC Activation in Melanoma Cell Lines Showing Primary Resistance to PLX403212

    PubMed Central

    Vergani, Elisabetta; Vallacchi, Viviana; Frigerio, Simona; Deho, Paola; Mondellini, Piera; Perego, Paola; Cassinelli, Giuliana; Lanzi, Cinzia; Testi, Maria Adele; Rivoltini, Licia; Bongarzone, Italia; Rodolfo, Monica

    2011-01-01

    PLX4032/vemurafenib is a first-in-class small-molecule BRAFV600E inhibitor with clinical activity in patients with BRAF mutant melanoma. Nevertheless, drug resistance develops in treated patients, and strategies to overcome primary and acquired resistance are required. To explore the molecular mechanisms involved in primary resistance to PLX4032, we investigated its effects on cell proliferation and signaling in a panel of 27 genetically characterized patient-derived melanoma cell lines. Cell sensitivity to PLX4032 was dependent on BRAFV600E and independent from other gene alterations that commonly occur in melanoma such as PTEN loss, BRAF, and MITF gene amplification. Two cell lines lacking sensitivity to PLX4032 and harboring a different set of genetic alterations were studied as models of primary resistance. Treatment with the MEK inhibitor UO126 but not with PLX4032 inhibited cell growth and ERK activation. Resistance to PLX4032 was maintained after CRAF down-regulation by siRNA indicating alternative activation of MEK-ERK signaling. Genetic characterization by multiplex ligation-dependent probe amplification and analysis of phosphotyrosine signaling by MALDI-TOF mass spectrometry analysis revealed the activation of MET and SRC signaling, associated with the amplification of MET and of CTNNB1 and CCND1 genes, respectively. The combination of PLX4032 with drugs or siRNA targeting MET was effective in inhibiting cell growth and reducing cell invasion and migration in melanoma cells with MET amplification; similar effects were observed after targeting SRC in the other cell line, indicating a role for MET and SRC signaling in primary resistance to PLX4032. Our results support the development of classification of melanoma in molecular subtypes for more effective therapies. PMID:22241959

  15. Physicochemical characteristics and sorption capacities of heavy metal ions of activated carbons derived by activation with different alkyl phosphate triesters

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Liu, Hai; Yang, Shaokun; Zhang, Jian; Zhang, Chenglu; Wu, Haiming

    2014-10-01

    Five alkyl phosphate triesters (APTEs), including trimethyl phosphate (TMP), triethyl phosphate (TEP), triisopropyl phosphate (TPP), tributyl phosphate (TBP) and trioctyl phosphate (TOP), were used as activating agents for preparing activated carbons (AC-APTEs) with high surface acidity and metal ion sorption capacity. N2 adsorption/desorption isotherms, surface morphologies, elemental compositions, results of Boehm's titration and sorption capacities of heavy metal ions of the carbons were investigated. AC-APTEs contained much more acidic groups and exhibited much less surface area (<500 m2/g) in comparison with activated carbon (AC-PPA, 1145 m2/g) obtained from phosphoric acid activation. For the AC-APTEs, AC-TOP had the highest surface area (488 m2/g), AC-TMP showed the highest yield (41.1%), and AC-TBP possessed the highest acidic groups (2.695 mmol/g), oxygen content (47.0%) and metal ion sorption capacities (40.1 mg/g for Ni(II) and 53.5 mg/g for Cd(II)). For the carbons, AC-APTEs showed much larger Ni(II) and Cd(II) sorption capacities than AC-PPA, except AC-TPP. The differences of the carbons in the physicochemical and sorption properties suggested surface chemistry of the carbons was the main factor influencing their sorption capacities whereas the pore structure played a secondary role.

  16. NF-κB dynamics show digital activation and analog information processing in cells

    NASA Astrophysics Data System (ADS)

    Tay, Savas; Hughey, Jake; Lee, Timothy; Lipniacki, Tomasz; Covert, Markus; Quake, Stephen

    2010-03-01

    Cells operate in ever changing environments using extraordinary communication capabilities. Cell-to-cell communication is mediated by signaling molecules that form spatiotemporal concentration gradients, which requires cells to respond to a wide range of signal intensities. We used high-throughput microfluidic cell culture, quantitative gene expression analysis and mathematical modeling to investigate how single mammalian cells respond to different concentrations of the signaling molecule TNF-α via the transcription factor NF-κB. We measured NF-κB activity in thousands of live cells under TNF-α doses covering four orders of magnitude. In contrast to population studies, the activation is a stochastic, switch-like process at the single cell level with fewer cells responding at lower doses. The activated cells respond fully and express early genes independent of the TNF-α concentration, while only high dose stimulation results in the expression of late genes. Cells also encode a set of analog parameters such as the NF-κB peak intensity, response time and number of oscillations to modulate the outcome. We developed a stochastic model that reproduces both the digital and analog dynamics as well as the gene expression profiles at all measured conditions, constituting a broadly applicable model for TNF-α induced NF-κB signaling in various types of cells.

  17. Natural carbon-14 activity of organic substances in streams

    USGS Publications Warehouse

    Rosen, A.A.; Rubin, M.

    1964-01-01

    Carbon-14 measurements made on organic contaminants extracted from streams show percentages of industrial waste and domestic sewage. The method, used previously for studies of the atmosphere, can be used in studies of pollution sources.

  18. [Surface characteristics of alkali modified activated carbon and the adsorption capacity of methane].

    PubMed

    Zhang, Meng-Zhu; Li, Lin; Liu, Jun-Xin; Sun, Yong-Jun; Li, Guo-Bin

    2013-01-01

    Coconut shell based activated carbon was modified by alkali with different concentrations. The surface structures of tested carbons were observed and analyzed by SEM and BET methods. Boehm's titration and SEM/EDS methods were applied to assay the functional groups and elements on the carbon surface. The adsorption of methane on tested carbons was investigated and adsorption behavior was described by the adsorption isotherms. Results showed that surface area and pore volume of modified carbon increased and surface oxygen groups decreased as the concentration of the alkali used increased, with no obvious change in pore size. When concentration of alkali was higher than 3.3 mol x L(-1), the specific surface area and pore volume of modified carbon was larger than that of original carbon. Methane adsorption capacity of alkali modified carbon increased 24%. Enlargement of surface area and pore volume, reduction of surface oxygen groups will benefit to enhance the methane adsorption ability on activated carbon. Adsorption behavior of methane followed the Langmuir isotherm and the adsorption coefficient was 163.7 m3 x mg(-1).

  19. Adsorption of direct dye onto activated carbon prepared from areca nut pod--an agricultural waste.

    PubMed

    Gopalswami, P; Sivakumar, N; Ponnuswamy, S; Venkateswaren, V; Kavitha, G

    2010-10-01

    Activated carbons are made from various agricultural wastes by physical and chemical activation. The preparation of activated carbon from agricultural waste could increase economic return and also provides an excellent method for the solid waste disposal thereby reduce pollution. Areca nut pod, which is an agricultural waste, has been used as a raw material to produce activated carbon (AAC) by four different methods. The adsorption of Direct blue dye used in textile industry on the porous areca nut pod activated carbon was investigated. The activated carbon AAC has an average surface area of 502 m2/g. CAC, the commercial reference was mainly micro porous with a surface area of 1026 m2/g .The study investigated the removal of direct dye from simulated water. The effects of adsorbent dosage, initial dye concentration, pH and contact time were studied. The results showed that as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly. The results indicate that AAC could be employed as low-cost alternative to commercial activated carbon in wastewater treatment for the removal of acid dyes.

  20. Granular Activated Carbon Performance Capability and Availability.

    DTIC Science & Technology

    1983-06-01

    5-11 Notes: 1. As total nitrobodies 2. Combined with RDX 3. Includes dissolved air flotation, sand filter, and GAC 4. Can be achieved with moderate...RDX-HMX Water and Air Research Inc Feoruary 1976 Facility Newoort Army Aunition Plant 0-27 ater Quality Assessment for the Proposed RDX-HMX Water and... Air Research Inc February 1976 Facility, McAlester Naval munition Depot. Vol I 0-28 luorovin Granular Carbon Treatment FMC Corp/EPA 1792-6D" N 07 71

  1. Mitochondrial biogenesis and proteome remodeling promotes one carbon metabolism for T cell activation

    PubMed Central

    Ron-Harel, Noga; Santos, Daniel; Ghergurovich, Jonathan M.; Sage, Peter T.; Reddy, Anita; Lovitch, Scott B.; Dephoure, Noah; Satterstrom, F. Kyle; Sheffer, Michal; Spinelli, Jessica B.; Gygi, Steven; Rabinowitz, Joshua D.; Sharpe, Arlene H.; Haigis, Marcia C.

    2017-01-01

    Summary Naïve T cell stimulation activates anabolic metabolism to fuel the transition from quiescence to growth and proliferation. Here we show that naïve CD4+ T cell activation induces a unique program of mitochondrial biogenesis and remodeling. Using mass spectrometry, we quantified protein dynamics during T cell activation. We identified substantial remodeling of the mitochondrial proteome over the first 24 hr of T cell activation to generate mitochondria with a distinct metabolic signature, with one carbon metabolism as the most induced pathway. Salvage pathways and mitochondrial one carbon metabolism, fed by serine, contribute to purine and thymidine synthesis to enable T cell proliferation and survival. Genetic inhibition of the mitochondrial serine catabolic enzyme SHMT2 impaired T cell survival in culture, and antigen-specific T cell abundance in vivo. Thus, during T cell activation, mitochondrial proteome remodeling generates specialized mitochondria with enhanced one carbon metabolism that is critical for T cell activation and survival. PMID:27411012

  2. Adsorption Properties of Lignin-derived Activated Carbon Fibers (LACF)

    SciTech Connect

    Contescu, Cristian I.; Gallego, Nidia C.; Thibaud-Erkey, Catherine; Karra, Reddy

    2016-04-01

    The object of this CRADA project between Oak Ridge National Laboratory (ORNL) and United Technologies Research Center (UTRC) is the characterization of lignin-derived activated carbon fibers (LACF) and determination of their adsorption properties for volatile organic compounds (VOC). Carbon fibers from lignin raw materials were manufactured at Oak Ridge National Laboratory (ORNL) using the technology previously developed at ORNL. These fibers were physically activated at ORNL using various activation conditions, and their surface area and pore-size distribution were characterized by gas adsorption. Based on these properties, ORNL did down-select five differently activated LACF materials that were delivered to UTRC for measurement of VOC adsorption properties. UTRC used standard techniques based on breakthrough curves to measure and determine the adsorption properties of indoor air pollutants (IAP) - namely formaldehyde and carbon dioxide - and to verify the extent of saturated fiber regenerability by thermal treatments. The results are summarized as follows: (1) ORNL demonstrated that physical activation of lignin-derived carbon fibers can be tailored to obtain LACF with surface areas and pore size distributions matching the properties of activated carbon fibers obtained from more expensive, fossil-fuel precursors; (2) UTRC investigated the LACF potential for use in air cleaning applications currently pursued by UTRC, such as building ventilation, and demonstrated their regenerability for CO2 and formaldehyde, (3) Both partners agree that LACF have potential for possible use in air cleaning applications.

  3. [The enzyme activity of bacilli showing promise for incorporation into biopreparations].

    PubMed

    Slabospitskaia, A T; Krymovskaia, S S; Reznik, S R

    1990-01-01

    The enzymic activity (amalyse, protease, lipase, pectolytic and cellulase) has been studied in 5 strains of aerobic spore-forming bacteria (Bacillus subtilis, B. licheniformis, B. coagulans, B. pumilis, B. badius) being of interest for creation of medical and prophylactic biopreparations. The above-mentioned enzymes were found in some studied strains. This may provide participation of bacilli in the degradation processes of a number of substrates in the digestive tract of a human being and animals and is an advantage of preparations from the genus Bacillus bacteria as compared with the available biopreparations of other microbial cultures for prophylaxis and treatment of gastrointestinal diseases.

  4. 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.

  5. Hydrogen Adsorption on Activated Carbon an Carbon Nanotubes Using Volumetric Differential Pressure Technique

    NASA Astrophysics Data System (ADS)

    Sanip, S. M.; Saidin, M. A. R.; Aziz, M.; Ismail, A. F.

    2010-03-01

    A simple hydrogen adsorption measurement system utilizing the volumetri differential pressure technique has been designed, fabricated and calibrated. Hydroge adsorption measurements have been carried out at temperatures 298 K and 77 K on activate carbon and carbon nanotubes with different surface areas. The adsorption data obtained will b helpful in understanding the adsorption property of the studied carbon materials using th fundamentals of adsorption theory. The principle of the system follows the Sievert-type metho The system measures a change in pressure between the reference cell, R1 and the sample cell S1, S2, S3 over a certain temperature range. R1, S1, S2, and S3 having known fixed volume The sample temperatures will be monitored by thermocouple TC while the pressures in R1 an S1, S2, S3 will be measured using a digital pressure transducer. The maximum operatin pressure of the pressure transducer is 20 bar and calibrated with an accuracy of ±0.01 bar. Hig purity hydrogen is being used in the system and the amount of samples for the study is betwee 1.0-2.0 grams. The system was calibrated using helium gas without any samples in S1, S2 an S3. This will provide a correction factor during the adsorption process providing an adsorption free reference point when using hydrogen gas resulting in a more accurate reading of th adsorption process by eliminating the errors caused by temperature expansion effects and oth non-adsorption related phenomena. The ideal gas equation of state is applied to calculate th hydrogen adsorption capacity based on the differential pressure measurements. Activated carbo with a surface area of 644.87 m2/g showed a larger amount of adsorption as compared to multiwalled nanotubes (commercial) with a surface area of 119.68 m2/g. This study als indicated that there is a direct correlation between the amounts of hydrogen adsorbed an surface area of the carbon materials under the conditions studied and that the adsorption significant at 77

  6. 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...

  7. Alcoholic Extract of Eclipta alba Shows In Vitro Antioxidant and Anticancer Activity without Exhibiting Toxicological Effects

    PubMed Central

    Arya, Rakesh Kumar; Dev, Kapil; Sharma, Chetan; Hossain, Zakir; Meena, Sanjeev; Arya, K. R.; Gayen, J. R.

    2017-01-01

    As per WHO estimates, 80% of people around the world use medicinal plants for the cure and prevention of various diseases including cancer owing to their easy availability and cost effectiveness. Eclipta alba has long been used in Ayurveda to treat liver diseases, eye ailments, and hair related disorders. The promising medicinal value of E. alba prompted us to study the antioxidant, nontoxic, and anticancer potential of its alcoholic extract. In the current study, we evaluated the in vitro cytotoxic and antioxidant effect of the alcoholic extract of Eclipta alba (AEEA) in multiple cancer cell lines along with control. We have also evaluated its effect on different in vivo toxicity parameters. Here, we found that AEEA was found to be most active in most of the cancer cell lines but it significantly induced apoptosis in human breast cancer cell lines by disrupting mitochondrial membrane potential and DNA damage. Moreover, AEEA treatment inhibited migration in both MCF 7 and MDA-MB-231 cells in a dose dependent manner. Further, AEEA possesses robust in vitro antioxidant activity along with high total phenolic and flavonoid contents. In summary, our results indicate that Eclipta alba has enormous potential in complementary and alternative medicine for the treatment of cancer. PMID:28250894

  8. Heterocyclic aromatic hydrocarbons show estrogenic activity upon metabolization in a recombinant transactivation assay.

    PubMed

    Brinkmann, Markus; Maletz, Sibylle; Krauss, Martin; Bluhm, Kerstin; Schiwy, Sabrina; Kuckelkorn, Jochen; Tiehm, Andreas; Brack, Werner; Hollert, Henner

    2014-05-20

    Heterocyclic aromatic hydrocarbons (hetero-PAHs) are increasingly studied at contaminated sites; especially at former industrial facilities where coal tar-oil was handled, e.g., wood treatment plants, high concentrations of hetero-PAHs are frequently detected in groundwater plumes. In previous studies, fractions of groundwater with high estrogenic activity contained hetero-PAHs and their hydroxylated metabolites. To evaluate this preliminary evidence, selected hetero-PAHs were screened for their estrogenic activity in lyticase yeast estrogen screen (LYES) and ER CALUX. All tested substances were inactive in the LYES. Hetero-PAHs such as acridine, xanthene, indole, 2-methylbenzofuran, 2,3-dimethylbenzofuran, dibenzofuran, dibenzothiophene, quinoline, and 6-methylquinoline were positive in the ER CALUX, with estradiol equivalence factors (EEFs) from 2.85 × 10(-7) to 3.18 × 10(-5). The EEF values of these substances were comparable to those of other xenoestrogens (e.g., alkylphenols or bisphenol A) that are sometimes found in surface water. Chemical analyses revealed that T47Dluc cells could metabolize most of the substances. Among the metabolites (tentatively) identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) were hydroxides and their keto tautomers, sulfates, sulfoxides, and N-oxides. Because of their high concentrations measured in groundwater, we conclude that hetero-PAHs and metabolites may be a potential risk and should be the subject of further research.

  9. X-ray microtomography shows pore structure and tortuosity in alkali-activated binders

    SciTech Connect

    Provis, John L.; Myers, Rupert J.; White, Claire E.; Rose, Volker; Deventer, Jannie S.J. van

    2012-06-15

    Durability of alkali-activated binders is of vital importance in their commercial application, and depends strongly on microstructure and pore network characteristics. X-ray microtomography ({mu}CT) offers, for the first time, direct insight into microstructural and pore structure characteristics in three dimensions. Here, {mu}CT is performed on a set of sodium metasilicate-activated fly ash/slag blends, using a synchrotron beamline instrument. Segmentation of the samples into pore and solid regions is then conducted, and pore tortuosity is calculated by a random walker method. Segmented porosity and diffusion tortuosity are correlated, and vary as a function of slag content (slag addition reduces porosity and increases tortuosity), and sample age (extended curing gives lower porosity and higher tortuosity). This is particularly notable for samples with {>=} 50% slag content, where a space-filling calcium (alumino)silicate hydrate gel provides porosity reductions which are not observed for the sodium aluminosilicate ('geopolymer') gels which do not chemically bind water of hydration.

  10. Medicinal plants and their isolated compounds showing anti-Trichomonas vaginalis- activity.

    PubMed

    Mehriardestani, Mozhgan; Aliahmadi, Atousa; Toliat, Tayebeh; Rahimi, Roja

    2017-04-01

    Trichomonas vaginalis is a major of non-viral sexually-transmitted infection and an important cause of serious obstetrical and gynecological complications. Treatment options for trichomoniasis are limited to nitroimidazole compounds. The increasing resistance and allergic reactions to nitroimidazole and recurrent trichomoniasis make it essential to identify and develop new drugs against trichomoniasis. Medicinal plants are an important source for discovery of new medications. This review discusses the anti-trichomonas effects of medicinal plants and their chemical constituents to find better options against this pathogenic protozoon. Electronic databases were searched to collect all data from the year 2000 through September 2015 for in vitro, in vivo and clinical studies on the effect of medicinal plants on T. vaginalis. A total of 95 in vitro and clinical studies were identified. Only four human studies were found in this review. The Asteracea, Lamiaceae and Myrtaceae families contained the greatest number of plants with anti-trichomonas activity. Persea americana, Ocimum basilicum and Verbascum thapsus were the most efficacious against T. vaginalis. Plant metabolites containing alkaloids, isoflavonoid glucosides, essential oils, lipids, saponins and sesquiterpene lactones were found to possess anti-trichomonas properties. Assessing the structure-activity of highly-potent anti-trichomonas phytochemicals is suggested for finding natural, semisynthetic and synthetic anti-trichomonas compounds. Further clinical studies are necessary for confirmation of natural anti-trichomonas substances and completion of their safety profiles.

  11. Bacillus cereus strain S2 shows high nematicidal activity against Meloidogyne incognita by producing sphingosine

    PubMed Central

    Gao, Huijuan; Qi, Gaofu; Yin, Rong; Zhang, Hongchun; Li, Chenggang; Zhao, Xiuyun

    2016-01-01

    Plant-parasitic nematodes cause serious crop losses worldwidely. This study intended to discover the antagonistic mechanism of Bacillus cereus strain S2 against Meloidogyne incognita. Treatment with B. cereus strain S2 resulted in a mortality of 77.89% to Caenorhabditis elegans (a model organism) and 90.96% to M. incognita. In pot experiment, control efficiency of B. cereus S2 culture or supernatants were 81.36% and 67.42% towards M. incognita, respectively. In field experiment, control efficiency was 58.97% towards M. incognita. Nematicidal substances were isolated from culture supernatant of B. cereus S2 by polarity gradient extraction, silica gel column chromatography and HPLC. Two nematicidal compounds were identified as C16 sphingosine and phytosphingosine by LC-MS. The median lethal concentration of sphingosine was determined as 0.64 μg/ml. Sphingosine could obviously inhibit reproduction of C. elegans, with an inhibition rate of 42.72% for 24 h. After treatment with sphingosine, ROS was induced in intestinal tract, and genital area disappeared in nematode. Furthermore, B. cereus S2 could induce systemic resistance in tomato, and enhance activity of defense-related enzymes for biocontrol of M. incognita. This study demonstrates the nematicidal activity of B. cereus and its product sphingosine, as well provides a possibility for biocontrol of M. incognita. PMID:27338781

  12. Preparation and characterization of activated carbon from a new raw lignocellulosic material: flamboyant (Delonix regia) pods.

    PubMed

    Vargas, Alexandro M M; Cazetta, André L; Garcia, Clarice A; Moraes, Juliana C G; Nogami, Eurica M; Lenzi, Ervim; Costa, Willian F; Almeida, Vitor C

    2011-01-01

    Activated carbons were prepared from flamboyant pods by NaOH activation at three different NaOH:char ratios: 1:1 (AC-1), 2:1 (AC-2), and 3:1 (AC-3). The properties of these carbons, including BET surface area, pore volume, pore size distribution, and pore diameter, were characterized from N(2) adsorption isotherms. The activated carbons obtained were essentially microporous and had BET surface area ranging from 303 to 2463 m(2) g(-1).(13)C (CP/MAS and MAS) solid-state NMR shows that the lignocellulosic structures were completely transformed into a polycyclic material after activation process, thermogravimetry shows a high thermal resistance, Boehm titration and Fourier-transform infrared spectroscopy allowed characterizing the presence of functional groups on the surface of activated carbons. Scanning electron microscopy images showed a high pore development. The experimental results indicated the potential use of flamboyant pods as a precursor material in the preparation of activated carbon.

  13. Elimination of textile dyes using activated carbons prepared from vegetable residues and their characterization.

    PubMed

    Peláez-Cid, Alejandra-Alicia; Herrera-González, Ana-María; Salazar-Villanueva, Martín; Bautista-Hernández, Alejandro

    2016-10-01

    In this study, three mesoporous activated carbons prepared from vegetable residues were used to remove acid, basic, and direct dyes from aqueous solutions, and reactive and vat dyes from textile wastewater. Granular carbons obtained by chemical activation at 673 K with phosphoric acid from prickly pear peels (CarTunaQ), broccoli stems (CarBrocQ), and white sapote seeds (CarZapQ) were highly efficient for the removal of dyes. Adsorption equilibrium studies were carried out in batch systems and treated with Langmuir and Freundlich isotherms. The maximum adsorption capacities calculated from the Langmuir isotherms ranged between 131.6 and 312.5 mg/g for acid dyes, and between 277.8 and 500.0 mg/g for basic dyes at 303 K. Our objective in this paper was to show that vegetable wastes can serve as precursors for activated carbons that can be used for the adsorption of dyes. Specifically CarBrocQ was the best carbon produced for the removal of textile dyes. The color removal of dyes present in textile wastewaters was compared with that of a commercial powdered carbon, and it was found that the carbons produced using waste material reached similar efficiency levels. Carbon samples were characterized by bulk density, point of zero charge, thermogravimetric analysis, elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, methylene blue adsorption isotherms at 303 K, and nitrogen adsorption isotherms at 77 K (SBET). The results show that the activated carbons possess a large specific surface area (1025-1177 m(2)/g) and high total pore volume (1.06-2.16 cm(3)/g) with average pore size diameters between 4.1 and 8.4 nm. Desorption and regeneration tests were made to test the viability of reusing the activated carbons.

  14. 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

  15. Oxidation of activated carbon: application to vinegar decolorization.

    PubMed

    López, Francisco; Medina, Francisco; Prodanov, Marin; Güell, Carme

    2003-01-15

    This article reports studies on the feasibility of increasing the decoloring capacity of a granular activated carbon (GAC) by using oxidation with air at 350 degrees C to modify its surface activity and porosity. The GAC, obtained from olive stones, had a maximum decolorization capacity of 92% for doses of 20 g/l, while the maximum decolorization capacity of the modified granular activated carbon (MGAC) was about 96% at a dose of 10 g/l. The increase in decoloring capacity is thought to be due to an increase in mesopore area (from 129 to 340 m2/g) in the MGAC. The maximum decoloring values and the doses needed to attain them are very close to values obtained in previous studies using coconut shell powder-activated carbon (94 and 98% for red and white vinegar for a dose of 10 g/l, respectively).

  16. Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes.

    PubMed

    Szlachta, M; Wójtowicz, P

    2013-01-01

    This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m(2)/g, MWCNTs 358 m(2)/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal.

  17. Comparing graphene, carbon nanotubes, and superfine powdered activated carbon as adsorptive coating materials for microfiltration membranes.

    PubMed

    Ellerie, Jaclyn R; Apul, Onur G; Karanfil, Tanju; Ladner, David A

    2013-10-15

    Multi-walled carbon nanotubes (MWCNTs), nano-graphene platelets (NGPs), and superfine powdered activated carbon (S-PAC) were comparatively evaluated for their applicability as adsorptive coatings on microfiltration membranes. The objective was to determine which materials were capable of contaminant removal while causing minimal flux reduction. Methylene blue and atrazine were the model contaminants. When applied as membrane coatings, MWCNTs had minimal retention capabilities for the model contaminants, and S-PAC had the fastest removal. The membrane coating approach was also compared with a stirred vessel configuration, in which the adsorbent was added to a stirred flask preceding the membrane cell. Direct application of the adsorbent to the membrane constituted a greater initial reduction in permeate concentrations of the model contaminants than with the stirred flask setup. All adsorbents except S-PAC showed flux reductions less than 5% after application as thin-layer membrane coatings, and flux recovery after membrane backwashing was greater than 90% for all materials and masses tested.

  18. 2, 4 dichlorophenol (2, 4-DCP) sorption from aqueous solution using granular activated carbon and polymeric adsorbents and studies on effect of temperature on activated carbon adsorption.

    PubMed

    Ghatbandhe, A S; Yenkie, M K N

    2008-04-01

    Adsorption equilibrium, kinetics and thermodynamics of 2,4-dichlorophenol (2,4-DCP), one of the most commonly used chlorophenol, onto bituminous coal based Filtrasorb-400 grade granular activated carbon, were studied in aqueous solution in a batch system with respect to temperature. Uptake capacity of activated carbon found to increase with temperature. Langmuir isotherm models were applied to experimental equilibrium data of 2, 4-DCP adsorption and competitive studies with respect to XAD resin were carried out. Equilibrium data fitted very well to the Langmuir equilibrium model. Adsorbent monolayer capacity 'Q0, Langmuir constant 'b' and adsorption rate constant 'k(a)' were evaluated at different temperatures for activated carbon adsorption. This data was then used to calculate the energy of activation of adsorption and also the thermodynamic parameters, namely the free energy of adsorption, deltaG0, enthalpy of adsorption, deltaH0 and the entropy of adsorption deltaS0. The obtained results showed that the monolayer capacity increases with the increase in temperatures. The obtained values of thermodynamic parameters showed that adsorption of 2,4 DCP is an endothermic process. Synthetic resin was not found efficient to adsorb 2,4 DCP compared to activated carbon. The order of adsorption efficiencies of three resins used in the study found as XAD7HP > XAD4 > XAD1180.

  19. Arabidopsis profilin isoforms, PRF1 and PRF2 show distinctive binding activities and subcellular distributions.

    PubMed

    Wang, Feng; Jing, Yanping; Wang, Zhen; Mao, Tonglin; Samaj, Jozef; Yuan, Ming; Ren, Haiyun

    2009-02-01

    Profilin is an actin-binding protein that shows complex effects on the dynamics of the actin cytoskeleton. There are five profilin isoforms in Arabidopsis thaliana L. However, it is still an open question whether these isoforms are functionally different. In the present study, two profilin isoforms from Arabidopsis, PRF1 and PRF2 were fused with green fluorescent protein (GFP) tag and expressed in Escherichia coli and A. thaliana in order to compare their biochemical properties in vitro and their cellular distributions in vivo. Biochemical analysis revealed that fusion proteins of GFP-PRF1 and GFP-PRF2 can bind to poly-L-proline and G-actin showing remarkable differences. GFP-PRF1 has much higher affinities for both poly-L-proline and G-actin compared with GFP-PRF2. Observations of living cells in stable transgenic A. thaliana lines revealed that 35S::GFP-PRF1 formed a filamentous network, while 35S::GFP-PRF2 formed polygonal meshes. Results from the treatment with latrunculin A and a subsequent recovery experiment indicated that filamentous alignment of GFP-PRF1 was likely associated with actin filaments. However, GFP-PRF2 localized to polygonal meshes resembling the endoplasmic reticulum. Our results provide evidence that Arabidopsis profilin isoforms PRF1 and PRF2 have different biochemical affinities for poly-L-proline and G-actin, and show distinctive localizations in living cells. These data suggest that PRF1 and PRF2 are functionally different isoforms.

  20. Testing Iodized Activated Carbon Filters with Non-Radio Active Methyl Iodide.

    DTIC Science & Technology

    1980-05-30

    and 4314, 4315, and 4316 are labora- to y impregnations using KI, KIO 3, hexamethylenetetramine and a pH 10 phosphate buffer (11). The agreement...14, Columbia Activated Carbon 207A 8 x 16, Sutcliffe, Speakman Co. Ltd. BPL 8 x 20, Activated Carbon Division, Calgon Corp. KITEG II Nuclear Consulting Services, Inc. TEDA triethylenediamine HMTA hexamethylenetetramine 52

  1. 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

  2. γ Sulphate PNA (PNA S): highly selective DNA binding molecule showing promising antigene activity.

    PubMed

    Avitabile, Concetta; Moggio, Loredana; Malgieri, Gaetano; Capasso, Domenica; Di Gaetano, Sonia; Saviano, Michele; Pedone, Carlo; Romanelli, Alessandra

    2012-01-01

    Peptide Nucleic Acids (PNAs), nucleic acid analogues showing high stability to enzyme degradation and strong affinity and specificity of binding toward DNA and RNA are widely investigated as tools to interfere in gene expression. Several studies have been focused on PNA analogues with modifications on the backbone and bases in the attempt to overcome solubility, uptake and aggregation issues. γ PNAs, PNA derivatives having a substituent in the γ position of the backbone show interesting properties in terms of secondary structure and affinity of binding toward complementary nucleic acids. In this paper we illustrate our results obtained on new analogues, bearing a sulphate in the γ position of the backbone, developed to be more DNA-like in terms of polarity and charge. The synthesis of monomers and oligomers is described. NMR studies on the conformational properties of monomers and studies on the secondary structure of single strands and triplexes are reported. Furthermore the hybrid stability and the effect of mismatches on the stability have also been investigated. Finally, the ability of the new analogue to work as antigene, interfering with the transcription of the ErbB2 gene on a human cell line overexpressing ErbB2 (SKBR3), assessed by FACS and qPCR, is described.

  3. Montmorillonite enhanced ciprofloxacin transport in saturated porous media with sorbed ciprofloxacin showing antibiotic activity

    NASA Astrophysics Data System (ADS)

    Chen, Hao; Gao, Bin; Yang, Liu-Yan; Ma, Lena Q.

    2015-02-01

    Antibiotic ciprofloxacin (CIP) is immobile in the subsurface but it has been frequently detected in the aquatic system. Therefore it is important to investigate the factors impacting CIP's mobilization in aquifer. Laboratory columns packed with sand were used to test colloid-facilitated CIP transport by 1) using kaolinite or montmorillonite to mobilize presorbed-CIP in a column or 2) co-transporting with CIP by pre-mixing them before transport. The Langmuir model showed that CIP sorption by montmorillonite (23 g kg- 1) was 100 times more effective than sand or kaolinite. Even with strong CIP complexation ability to Fe/Al coating on sand surface, montmorillonite promoted CIP transport, but not kaolinite. All presorbed-CIP by sand was mobilized by montmorillonite after 3 pore volumes through co-transporting of CIP with montmorillonite. The majority of CIP was fixed onto the montmorillonite interlayer but still showed inhibition of bacteria growth. Our results suggested that montmorillonite with high CIP sorption ability can act as a carrier to enhance CIP's mobility in aquifer.

  4. Characterization of mesoporous activated carbons prepared by pyrolysis of sewage sludge with pyrolusite.

    PubMed

    Liu, Chen; Tang, Zhengguang; Chen, Yao; Su, Shijun; Jiang, Wenju

    2010-02-01

    Activated carbons were prepared from sewage sludge by chemical activation. Pyrolusite was added as a catalyst during activation and carbonization. The influence of the mineral addition on the properties of the activated carbons produced was evaluated. The results show that activated carbons from pyrolusite-supplemented sewage sludge had up to a 75% higher BET surface area and up to a 66% increase in mesoporosity over ordinary sludge-based activated carbons. Batch adsorption experiments applying the prepared adsorbents to synthetic dye wastewater treatment yielded adsorption data well fitted to the Langmuir isotherm. The adsorbents from pyrolusite-supplemented sludges performed better in dye removal than those without mineral addition, with the carbon from pyrolusite-augmented sludge T2 presenting a significant increase in maximum adsorption capacity of 50mg/g. The properties of the adsorbents were improved during pyrolusite-catalyzed pyrolysis via enhancement of mesopore production, thus the mesopore channels may provide fast mass transfer for large molecules like dyes.

  5. Nitrate uptake improvement by modified activated carbons developed from two species of pine cones.

    PubMed

    Nunell, G V; Fernandez, M E; Bonelli, P R; Cukierman, A L

    2015-02-15

    Activated carbons from two species of pine cones (Pinus canariensis and Cupressus sempervirens) were prepared by phosphoric acid activation and tested for the removal of nitrate ions from aqueous solution. To investigate the feasibility of improving their nitrate adsorption capacity, two different post-treatments—a thermal treatment and a treatment with saturated urea solution—were also applied to the prepared activated carbons. Comparison of the treated and untreated activated carbons showed that both post-treatments improved the nitrate adsorption performance more than twice. The maximum adsorption capacity, as evaluated from determination of the adsorption isotherms for the P. canariensis based carbons, and their proper representation by the Langmuir model, demonstrated that the post-treatment with the urea solution led to activated carbons with increased nitrate removal effectiveness, even superior to other reported results. Enhancements in their adsorption capacity could be mainly ascribed to higher contents of nitrogen and basic functional groups, whereas porous structure of the activated carbons did not seem to play a key role in the nitrate uptake.

  6. Different solvents for the regeneration of the exhausted activated carbon used in the treatment of coking wastewater.

    PubMed

    Guo, Dongsheng; Shi, Qiantao; He, Binbin; Yuan, Xiaoying

    2011-02-28

    The solvents n-pentane, methylene dichloride, ethyl ether and dodecylbenzenesulphonic acid sodium were used to regenerate exhausted activated carbon used in the process of treating coking wastewater, and the efficiency, ability, and optimum conditions of the different solvents on this regeneration were investigated. The results indicate that n-pentane could effectively remove refractory organic compounds in the coking wastewater adsorbed on the surface of activated carbon and could repeatedly regenerate the exhausted activated carbon to recover its adsorption activity. Under the conditions of a regeneration time of 20 min, a regeneration temperature of 25°C, an activated carbon drying time of 300 min, and an activated carbon drying temperature of 150°C, n-pentane had the best regeneration efficiency, at 98.27%, for exhausted activated carbon. Gas chromatography-mass spectrometry analysis results show that the nature of the activated carbon regenerated by organic solvents had no remarkable change in adsorption for the main types of organic compounds in coking wastewater. The good regenerative effect of n-pentane on the activated carbon may be due its stronger desorption of esters embedded within the internal structure of activated carbon.

  7. 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.

  8. Heterogeneous and homogeneous catalytic ozonation of benzothiazole promoted by activated carbon: kinetic approach.

    PubMed

    Valdés, Héctor; Zaror, Claudio A

    2006-11-01

    Ozone oxidation combined with activated carbon adsorption (O(3)/AC) has recently started to be developed as a single process for water and wastewater treatment. While a number of aspects of aqueous ozone decomposition are well understood, the importance and relationship between aqueous ozone decomposition and organic contaminant degradation in the presence of activated carbon is still not clear. This study focuses on determining the contribution of homogeneous and heterogeneous reactions to organic contaminants removal in O(3)/AC system. Benzothiazole (BT) was selected as a target organic pollutant due to its environmental concern. A reactor system based on a differential circular flow reactor composed by a 19 cm(3) activated carbon fixed bed column and 1 dm(3) storage tank was used. Ozone was produced from pure and dry oxygen using an Ozocav ozone generator rated at 5 g O(3)h(-1). Experimental results show that BT removal rate was proportional to activated carbon dosage. Activated carbon surface contribution to BT oxidation reactions with ozone, increased with pH in absence of radical scavengers. The radical reaction contribution within the pH range 2-11 accounted for 67-83% for BT removal in O(3)/AC simultaneous treatment. Results suggest that at pH higher than the pH of the point of zero charge of the activated carbon dissociated acid groups such as carboxylic acid anhydrides and carboxylic acids present on activated carbon surface could be responsible for the observed increase in the ozone decomposition reaction rate. A simplified mechanism and a kinetic scheme representing the contribution of homogeneous and heterogeneous reactions on BT ozonation in the presence of activated carbon is proposed.

  9. Trivalent chromium removal from wastewater using low cost activated carbon derived from agricultural waste material and activated carbon fabric cloth.

    PubMed

    Mohan, Dinesh; Singh, Kunwar P; Singh, Vinod K

    2006-07-31

    An efficient adsorption process is developed for the decontamination of trivalent chromium from tannery effluents. A low cost activated carbon (ATFAC) was prepared from coconut shell fibers (an agricultural waste), characterized and utilized for Cr(III) removal from water/wastewater. A commercially available activated carbon fabric cloth (ACF) was also studied for comparative evaluation. All the equilibrium and kinetic studies were conducted at different temperatures, particle size, pHs, and adsorbent doses in batch mode. The Langmuir and Freundlich isotherm models were applied. The Langmuir model best fit the equilibrium isotherm data. The maximum adsorption capacities of ATFAC and ACF at 25 degrees C are 12.2 and 39.56 mg/g, respectively. Cr(III) adsorption increased with an increase in temperature (10 degrees C: ATFAC--10.97 mg/g, ACF--36.05 mg/g; 40 degrees C: ATFAC--16.10 mg/g, ACF--40.29 mg/g). The kinetic studies were conducted to delineate the effect of temperature, initial adsorbate concentration, particle size of the adsorbent, and solid to liquid ratio. The adsorption of Cr(III) follows the pseudo-second-order rate kinetics. From kinetic studies various rate and thermodynamic parameters such as effective diffusion coefficient, activation energy and entropy of activation were evaluated. The sorption capacity of activated carbon (ATFAC) and activated carbon fabric cloth is comparable to many other adsorbents/carbons/biosorbents utilized for the removal of trivalent chromium from water/wastewater.

  10. A nanoporous metallic mat showing excellent and stable surface enhanced Raman spectroscopy activities.

    PubMed

    Kim, Nam-Jung; Lin, Mengshi

    2010-08-01

    A novel nanoporous mat structure was made of gold nanoparticles through a simple, inexpensive self-assembly process as a bottom-up approach to produce an affordable and high-quality SERS substrate. This nanostructure mat shows an excellent SERS reproducibility, physical stability, and strong Raman enhancement, which may satisfy all the criteria as a universal-type SERS substrate. The limit of detection for crystal violet dye on the nanostructured substrates is estimated to reach ppb levels and the SERS enhancement factor is found to be two orders of magnitude higher than that from conventional de-alloy nanoporous films. Mechanical strength of the nano-cluster network can be increased by a post-assembly annealing process. The nanoparticle-based SERS substrate holds promise in practical sensing applications toward a rapid determination of harmful substances or contaminants in food and environment.

  11. 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 25-65°C and inlet CO2 concentration range of 10-30 mol% 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 273 K, 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 0.62 cm(3)/g and surface area of 1400 m(2)/g had the highest CO2 adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO2 and 25°C. 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 50 cycles with low temperature (160°C) regeneration.

  12. Synthesis of carbon fibers and activated carbon fibers from coal liquids

    SciTech Connect

    Fei, Y.Q.; Derbyshire, F.; Jagtoyen, M.; Kimber, G.

    1994-12-31

    The production and application of low-cost, general purpose carbon fibers and activated fibers are emerging technologies with exciting potential, although at present their cost is too high to find widespread use. Production and R and D have been limited and to data, only a small range of precursors has been studied: petroleum pitches, coal extracts and coal tar pitches. Both processing costs and the properties of the fiber products are dependent on the nature of the starting material. Commercial precursors have been limited to the pitches produced from high temperature pyrolysis or cracking processes and are similar in composition and molecular structure. Suitable coal-based precursors can be produced with a wide range of composition, and at moderate cost, by methods such as low temperature carbonization, solvent extraction, hydropyrolysis and mild coal liquefaction. It is of interest to investigate the synthesis of carbon fibers and activated carbon fibers from precursors of different origins to elucidate the influence of precursor materials on fiber formation and processing, and their structure and properties. It is also of practical importance to understand the relationships between the type of starting materials (for example, coals) and the processing methods, and the properties of fiber precursors that can be produced from them. In the present study, the authors describe the synthesis of carbon fibers and activated carbon fibers from the products of the first stage of coal liquefaction.

  13. Adsorption of aromatic organic contaminants by graphene nanosheets: comparison with carbon nanotubes and activated carbon.

    PubMed

    Apul, Onur Guven; Wang, Qiliang; Zhou, Yang; Karanfil, Tanju

    2013-03-15

    Adsorption of two synthetic organic compounds (SOCs; phenanthrene and biphenyl) by two pristine graphene nanosheets (GNS) and one graphene oxide (GO) was examined and compared with those of a coal base activated carbon (HD4000), a single-walled carbon nanotube (SWCNT), and a multi-walled carbon nanotube (MWCNT) in distilled and deionized water and in the presence of natural organic matter (NOM). Graphenes exhibited comparable or better adsorption capacities than carbon nanotubes (CNTs) and granular activated carbon (GAC) in the presence of NOM. The presence of NOM reduced the SOC uptake of all adsorbents. However, the impact of NOM on the SOC adsorption was smaller on graphenes than CNTs and activated carbons. Furthermore, the SOC with its flexible molecular structure was less impacted from NOM preloading than the SOC with planar and rigid molecular structure. The results indicated that graphenes can serve as alternative adsorbents for removing SOCs from water. However, they will also, if released to environment, adsorb organic contaminants influencing their fate and impact in the environment.

  14. High surface area activated carbon prepared from cassava peel by chemical activation.

    PubMed

    Sudaryanto, Y; Hartono, S B; Irawaty, W; Hindarso, H; Ismadji, S

    2006-03-01

    Cassava is one of the most important commodities in Indonesia, an agricultural country. Cassava is one of the primary foods in our country and usually used for traditional food, cake, etc. Cassava peel is an agricultural waste from the food and starch processing industries. In this study, this solid waste was used as the precursor for activated carbon preparation. The preparation process consisted of potassium hydroxide impregnation at different impregnation ratio followed by carbonization at 450-750 degrees C for 1-3 h. The results revealed that activation time gives no significant effect on the pore structure of activated carbon produced, however, the pore characteristic of carbon changes significantly with impregnation ratio and carbonization temperature. The maximum surface area and pore volume were obtained at impregnation ratio 5:2 and carbonization temperature 750 degrees C.

  15. Potential application of activated carbon from maize tassel for the removal of heavy metals in water

    NASA Astrophysics Data System (ADS)

    Olorundare, O. F.; Krause, R. W. M.; Okonkwo, J. O.; Mamba, B. B.

    Water-pollution problems worldwide have led to an acute shortage of clean and pure water for both domestic and human consumption. Various technologies and techniques are available for water treatment which includes the use of activated carbon. In this study activated carbons used for the removal of lead (II) ions from water samples were prepared from maize tassels (an agricultural waste residue) which were modified using physical and chemical activation. In the physical activation CO2 was used as the activating agent, while in chemical activation H3PO4 with an impregnation ratio ranging from 1 to 4 was employed. The maize tassel was pyrolysed at different temperatures ranging from 300 °C to 700 °C in an inert atmosphere for a period of 60 min and activated at 700 °C for 30 min. The effects of activation temperature, impregnation ratio and duration were examined. The resultant modified tassels were characterised by measuring their particle-size distribution, porosities, pore volume, and pore-size distribution using scanning electron microscopy (SEM). The activated carbon produced by chemical activation had the highest BET surface area ranging from 623 m2 g-1 to 1 262 m2 g-1. The surface chemistry characteristics of the modified tassels were determined by FT-IR spectroscopy and Boehm’s titration method. The experimental data proved that properties of activated carbon depend on final temperature of the process, impregnation ratio and duration of the treatment at final temperature. The adsorption studies showed that chemically prepared activated carbon performed better than physically prepared activated carbon.

  16. 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.

  17. Removal of tinidazole from waters by using ozone and activated carbon in dynamic regime.

    PubMed

    Rivera-Utrilla, J; Sánchez-Polo, M; Prados-Joya, G; Ferro-García, M A; Bautista-Toledo, I

    2010-02-15

    The main objective of the present study was to analyze the efficacy of technologies based on ozone and activated carbon in dynamic regime to remove organic micropollutants from waters, using the antibiotic tinidazole (TNZ) as a model compound. Results obtained in static regime show that the presence of activated carbon (GAC) during tinidazole ozonation: (i) increases its removal rate, (ii) reduces oxidation by-product toxicity, and (iii) reduces the concentration of dissolved organic matter. Study of the ozone/activated carbon system in dynamic regime showed that ozonation of tinidazole before the adsorption process considerably improves column performance, increasing the volume of water treated. It was observed that the efficacy of the treatment considerably increased with a shorter contact time between TNZ and O(3) streams before entering the column allowing a much higher volume of TNZ solution to be treated compared with the use of activated carbon alone, and reducing by 75% the amount of activated carbon required per unit of treated water volume. TNZ removal by the O(3)/GAC system is lower in natural waters and especially in wastewaters, than in ultrapure water. The toxicity results obtained during TNZ treatment with O(3)/GAC system showed that toxicity was directly proportional to the concentration of TNZ in the effluent, verifying that oxidation of the organic matter in the natural waters did not increase the toxicity of the system.

  18. Estradiol shows anti-skin cancer activities through decreasing MDM2 expression.

    PubMed

    Li, Li; Feng, Jianguo; Chen, Ying; Li, Shun; Ou, Mengting; Sun, Weichao; Tang, Liling

    2017-01-31

    Estradiol plays important roles in many biological responses inducing tumor genesis and cancer treatment. However, the effects of estradiol on tumors were inconsistent among a lot of researches and the mechanism is not fully understood. Our previous study indicated that splicing factor hnRNPA1 could bind to the human homologue of mouse double minute (MDM2), an oncogene which has been observed to be over-expressed in numerous types of cancers. In this research, we investigated whether and how estradiol correlate to cancer cell behaviors through heterogeneous nuclear ribonucleoprotein (hnRNPA1) and MDM2. Results showed that 10×10-13Mestradiol elevated the expression of hnRNPA1 regardless ER expression in cells, and then down-regulated the expression of MDM2. At the same time, estradiol inhibited cell proliferation, migration and epithelial-mesenchymal transition progression of A375 and GLL19 cells. While, knocking down hnRNPA1 through the transfection of hnRNPA1 siRNA led to the increase of MDM2 at both protein level and gene level In vivo experiment, subcutaneous injection with estradiol every two days near the tumor at doses of 2.5mg/kg/d suppressed tumor growth and reduced MDM2 expression. In a word, via increasing hnRNPA1 level and then reducing the expression of MDM2, estradiol prevented carcinogenesis in melanomas. We confirmed therapeutic effect of estradiol, as well as a new way for estradiol to resist skin cancer.

  19. The environmental applications of activated carbon/zeolite composite materials.

    PubMed

    Foo, K Y; Hameed, B H

    2011-02-17

    Over the past couple of years, the resurgence of placing an effective and sustainable amendment to combat against the auxiliary industrial entities, remains a highly contested agenda from a global point. With the renaissance of activated carbon, there has been a steadily growing interest in the research field. Recently, the adoption of zeolite composite, a prestigious advanced catalyst which formulates the enhancement of adsorption rate and hydrogen storage capability, has fore fronted to be a new growing branch in the scientific community. Confirming the assertion, this paper presents a state of art review of activated carbon/zeolite composite technology, its fundamental background studies, and environmental implications. Moreover, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of activated carbon/zeolite composite represents a potentially viable and powerful tool, leading to the plausible improvement of environmental preservation.

  20. Detoxification of pesticide waste via activated carbon adsorption process.

    PubMed

    Foo, K Y; Hameed, B H

    2010-03-15

    Concern about environmental protection has increased over the years from a global viewpoint. To date, the percolation of pesticide waste into the groundwater tables and aquifer systems remains an aesthetic issue towards the public health and food chain interference. With the renaissance of activated carbon, there has been a consistent growing interest in this research field. Confirming the assertion, this paper presents a state of art review of pesticide agrochemical practice, its fundamental characteristics, background studies and environmental implications. Moreover, the key advance of activated carbon adsorption, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of activated carbon adsorption represents a plausible and powerful circumstance, leading to the superior improvement of environmental preservation.

  1. Preparation of activated carbon from wet sludge by electrochemical-NaClO activation.

    PubMed

    Miao, Chen; Ye, Caihong; Zhu, Tianxing; Lou, Ziyang; Yuan, Haiping; Zhu, Nanwen

    2014-01-01

    Activated carbon (AC) from sludge is one potential solution for sewage sludge disposal, while the drying sludge is cost and time consuming for preparation. AC preparation from the wet sludge with electrochemical-NaClO activation was studied in this work. Three pretreatment processes, i.e. chemical activation, electrolysis and electrochemical-reagent reaction, were introduced to improve the sludge-derived AC properties, and the optimum dosage of reagent was tested from the 0.1:1 to 1:1 (mass rate, reagent:dried sludge). It was shown that the electrochemical-NaClO preparation is the best method under the test conditions, in which AC has the maximum Brunauer, Emmett and Teller area of 436 m²/g at a mass ratio of 0.7. Extracellular polymeric substances in sludge can be disintegrated by electrochemical-NaClO pretreatment, with a disintegration degree of more than 45%. The percentage of carbon decreased from 34.16 to 8.81 after treated by electrochemical-NaClO activation. Fourier transform infrared spectra showed that a strong C-Cl stretching was formed in electrochemical-NaClO prepared AC. The maximum adsorption capacity of AC reaches 109 mg/g on MB adsorption experiment at pH 10 and can be repeated for three times with high removal efficiency after regeneration.

  2. [Degradation of Acid Orange 7 with Persulfate Activated by Silver Loaded Granular Activated Carbon].

    PubMed

    Wang, Zhong-ming; Huang, Tian-yin; Chen, Jia-bin; Li, Wen-wei; Zhang, Li-ming

    2015-11-01

    Granular activated carbon with silver loaded as activator (Ag/GAC) was prepared using impregnation method. N2 adsorption, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were adopted to characterize the Ag/GAC, showing that silver was successfully loaded on granular activated carbon. The oxidation degradation of acid orange 7 (AO7) by the Ag/GAC activated by persulfate (PS) was investigated at ambient temperature. The influences of factors such as Ag loading, PS or Ag/GAC dosages and initial pH on the degradation of AO7 were evaluated. The results demonstrated that the degradation rate of AO7 could reach more than 95.0% after 180 min when the Ag loading content, PS/AO7 molar ratio, the Ag/GAC dosage were 12.7 mg x g(-1), 120: 1, 1.0 g x L(-1), respectively. The initial pH had significant effect on the AO7 degradation, with pH 5.0 as the optimal pH for the degradation of AO7. The possible degradation pathway was proposed for the AO7 degradation by using UV-visible spectroscopy and gas chromatography-mass spectrometry (GG/MS). The azo bond and naphthalene ring in the AO7 were destroyed during the degradation, with phthalic acid and acetophenone as the main degradation products.

  3. KefF, the regulatory subunit of the potassium efflux system KefC, shows quinone oxidoreductase activity.

    PubMed

    Lyngberg, Lisbeth; Healy, Jessica; Bartlett, Wendy; Miller, Samantha; Conway, Stuart J; Booth, Ian R; Rasmussen, Tim

    2011-09-01

    Escherichia coli and many other Gram-negative pathogenic bacteria protect themselves from the toxic effects of electrophilic compounds by using a potassium efflux system (Kef). Potassium efflux is coupled to the influx of protons, which lowers the internal pH and results in immediate protection. The activity of the Kef system is subject to complex regulation by glutathione and its S conjugates. Full activation of KefC requires a soluble ancillary protein, KefF. This protein has structural similarities to oxidoreductases, including human quinone reductases 1 and 2. Here, we show that KefF has enzymatic activity as an oxidoreductase, in addition to its role as the KefC activator. It accepts NADH and NADPH as electron donors and quinones and ferricyanide (in addition to other compounds) as acceptors. However, typical electrophilic activators of the Kef system, e.g., N-ethyl maleimide, are not substrates. If the enzymatic activity is disrupted by site-directed mutagenesis while retaining structural integrity, KefF is still able to activate the Kef system, showing that the role as an activator is independent of the enzyme activity. Potassium efflux assays show that electrophilic quinones are able to activate the Kef system by forming S conjugates with glutathione. Therefore, it appears that the enzymatic activity of KefF diminishes the redox toxicity of quinones, in parallel with the protection afforded by activation of the Kef system.

  4. Oxygen-18 incorporation into malic acid during nocturnal carbon dioxide fixation in crassulacean acid metabolism plants: a new approach to estimating in vivo carbonic anhydrase activity

    SciTech Connect

    Holtum, J.A.M.; Summons, R.; Roeske, C.A.; Comins, H.N.; O'Leary, M.H.

    1984-01-01

    Crassulacean acid metabolism (CAM) plants fix carbon dioxide at night by the carboxylation of phosphoenolpyruvate. If CO2 fixation is conducted with TC YO2, then in the absence of carbonic anhydrase, the malate formed by dark CO2 fixation should also contain high levels of carbon-13 and oxygen-18. Conversely, if carbonic anhydrase is present and highly active, oxygen exchange between CO2 and cellular H2O will occur more rapidly than carboxylation, and the ( TC) malate formed will contain little or no oxygen-18 above the natural abundance level. The presence of oxygen-18 in these molecules can be detected either by nuclear magnetic resonance or by mass spectrometry. Studies of phosphoenolpyruvate carboxylase in the presence and absence of carbonic anhydrase in vitro confirm the validity of the method. When CAM plants are studied by this method, we find that most species show incorporation of a significant amount of oxygen-18. Comparison of these results with results of isotope fractionation and gas exchange studies permits calculation of the in vivo activity of carbonic anhydrase toward HCO3 compared with that of phosphoenolpyruvate carboxylase. The ratio (carbonic anhydrase activity/phosphoenolpyruvate carboxylase activity) is species dependent and varies from a low of about 7 for Ananas comosus to values near 20 for Hoya carnosa and Bryophyllum pinnatum, 40 for Kalanchoee daigremontiana, and 100 or greater for Bryophyllum tubiflorum, Kalanchoee serrata, and Kalanchoae tomentosa. Carbonic anhydrase activity increases relative to phosphoenolpyruvate carboxylase activity at higher temperature. 37 references, 2 figures, 8 tables.

  5. Activation and splitting of carbon dioxide on the surface of an inorganic electride material.

    PubMed

    Toda, Yoshitake; Hirayama, Hiroyuki; Kuganathan, Navaratnarajah; Torrisi, Antonio; Sushko, Peter V; Hosono, Hideo

    2013-01-01

    Activation of carbon dioxide is the most important step in its conversion into valuable chemicals. Surfaces of stable oxide with a low work function may be promising for this purpose. Here we report that the surfaces of the inorganic electride [Ca24Al28O64](4+)(e(-))4 activate and split carbon dioxide at room temperature. This behaviour is attributed to a high concentration of localized electrons in the near-surface region and a corrugation of the surface that can trap oxygen atoms and strained carbon monoxide and carbon dioxide molecules. The [Ca24Al28O64](4+)(e(-))4 surface exposed to carbon dioxide is studied using temperature-programmed desorption, and spectroscopic methods. The results of these measurements, corroborated with ab initio simulations, show that both carbon monoxide and carbon dioxide adsorb on the [Ca24Al28O64](4+)(e(-))4 surface at RT and above and adopt unusual configurations that result in desorption of molecular carbon monoxide and atomic oxygen upon heating.

  6. Adsorption characteristics of acetone, chloroform and acetonitrile on sludge-derived adsorbent, commercial granular activated carbon and activated carbon fibers.

    PubMed

    Tsai, Jiun-Horng; Chiang, Hsiu-Mei; Huang, Guan-Yinag; Chiang, Hung-Lung

    2008-06-15

    The adsorption characteristics of chloroform, acetone, and acetonitrile on commercial activated carbon (C1), two types of activated carbon fibers (F1 and F2), and sludge adsorbent (S1) was investigated. The chloroform influent concentration ranged from 90 to 7800 ppm and the acetone concentration from 80 to 6900 ppm; the sequence of the adsorption capacity of chloroform and acetone on adsorbents was F2>F1 approximately C1 approximately S1. The adsorption capacity of acetonitrile ranged from 4 to 100 mg/g, corresponding to the influent range from 43 to 2700 ppm for C1, S1, and F1. The acetonitrile adsorption capacity of F2 was approximately 20% higher than that of the other adsorbents at temperatures<30 degrees C. The Freundlich equation fit the data better than the Langmuir and Dubinin-Radushkevich (D-R) equations. The adsorption rate of carbon fibers is higher than that of the other adsorbents due to their smaller fiber diameter and higher surface area. The micropore diffusion coefficient of VOC on activated carbon and sludge adsorbent was approximately 10(-4) cm2 s(-1). The diffusion coefficient of VOC on carbon fibers ranged from 10(-8) to 10(-7) cm2 s(-1). The small carbon fiber pore size corresponds to a smaller diffusion coefficient.

  7. 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.

  8. 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.

  9. 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.

  10. Carbon-based supercapacitors produced by activation of graphene.

    PubMed

    Zhu, Yanwu; Murali, Shanthi; Stoller, Meryl D; Ganesh, K J; Cai, Weiwei; Ferreira, Paulo J; Pirkle, Adam; Wallace, Robert M; Cychosz, Katie A; Thommes, Matthias; Su, Dong; Stach, Eric A; Ruoff, Rodney 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(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.

  11. 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.

  12. 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.

  13. Arundo donax cane as a precursor for activated carbons preparation by phosphoric acid activation.

    PubMed

    Vernersson, T; Bonelli, P R; Cerrella, E G; Cukierman, A L

    2002-06-01

    Canes from Arundo donax, a herbaceous rapid-growing plant, were used as precursor for activated carbon preparation by phosphoric acid activation under a self-generated atmosphere. The influence of the carbonization temperature in the range 400-550 degrees C and of the weight ratio phosphoric acid to precursor (R = 1.5-2.5) on the developed porous structure of the resulting carbons was studied for 1 h of carbonization time. Surface properties of the activated carbons were dependent on a combined effect of the conditions employed. Carbons developed either with R = 1.5 over the range 400-500 degrees C, or with R = 2 at 500 degrees C exhibited surface areas of around 1100 m2/g, the latter conditions promoting a larger pore volume and enhanced mesoporous character. For both ratios, temperature above 500 degrees C led to reduction in porosity development. A similar effect was found for the highest ratio (R = 2.5) and 500 degrees C. The influence of carrying out the carbonization either for times shorter than 1 h or under flowing N2 was also examined at selected conditions (R = 2, 500 degrees C). Shorter times induced increase in the surface area (approximately 1300 m2/g), yielding carbons with smaller mean pore radius. Activated carbons obtained under flowing N2 possessed predominant microporous structures and larger ash contents than the samples derived in the self-generated atmosphere.

  14. 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.

  15. 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

  16. Preparation of Paper Containing Activated Carbon.

    DTIC Science & Technology

    1984-06-01

    development of charcoal paper. RESUME On a obtenu du papier contenant du charbon actif en dispersant du charbon r~duit en poudre et en versant des agents de...sa capaciti d’adsorption et de ritention du charbon . Ce papier pourrait servir d𔄀crans dans une salle de contr~le de contamination pour le balayage...contenant du charbon . "l-ii:: . ---:.-o * *** * *. .. t C Cd. .. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 S 2 INTRODUCTION . Activated

  17. Removal of Heavy Metal Ions and Diethylenetriamine Species from Solutions by Magnetic Activated Carbon

    NASA Astrophysics Data System (ADS)

    Liu, Kaiwen

    Even though activated carbon is widely used in the removal of contaminants from effluents, it is difficult to be completely recovered by screening or classification. In this project, we prepared a magnetic form of activated carbon (M-AC) by co-precipitation of iron oxides onto activated carbon surface. M-AC can be separated from solutions by applying an external magnetic field and regenerated for reuse. The synthesized M-AC was characterized by X-ray diffraction, specific surface area measurement, and scanning electron microscope. Characterization results show that the major phase of coated iron oxides is magnetite (Fe 3O4). Batch adsorption experiments were carried out for single-component and multi-component solutions. M-AC shows a better adsorption capacity for singlecomponent of Cu (II), Ni (II), or diethylenetriamine (DETA) and for multiple-components of Cu-DETA and Ni-DETA complexes in deionized water than activated carbon. M-AC also shows the potential application in carbon-in-pulp process for gold recovery.

  18. Nanoconfinement in activated mesoporous carbon of calcium borohydride for improved reversible hydrogen storage.

    PubMed

    Comănescu, Cezar; Capurso, Giovanni; Maddalena, Amedeo

    2012-09-28

    Mesoporous carbon frameworks were synthesized using the soft-template method. Ca(BH(4))(2) was incorporated into activated mesoporous carbon by the incipient wetness method. The activation of mesoporous carbon was necessary to optimize the surface area and pore size. Thermal programmed absorption measurements showed that the confinement of this borohydride into carbon nanoscaffolds improved its reversible capacity (relative to the reactive portion) and performance of hydrogen storage compared to unsupported borohydride. Hydrogen release from the supported hydride started at a temperature as low as 100 °C and the dehydrogenation rate was fast compared to the bulk borohydride. In addition, the hydrogen pressure necessary to regenerate the borohydride from the dehydrogenation products was reduced.

  19. 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.

  20. Nitrogen-Containing Carbon Nanotube Synthesized from Polymelem and Activated Carbon Derived from Polymer Blend

    NASA Astrophysics Data System (ADS)

    Qin, Nan

    Polymelem possesses a polymeric structure of heptazine (C6N 7) rings connected by amine bridges and our study has demonstrated that it is a promising precursor for the synthesis of nitrogen-containing carbon materials. Nitrogen-containing carbon nanotube (NCNT) was produced by pyrolyzing polymelem as a dual source of carbon and nitrogen with Raney nickel in a high pressure stainless steel cell. Activated carbon was produced from poly(ether ether ketone)/poly(ether imide) (PEEK/PEI blend) and incorporated with polymelem to enhance the hydrogen adsorption. Polymelem was successfully synthesized by pyrolyzing melamine at 450--650 °C and its structure was elucidated by 13C solid state NMR, FTIR, and XRD. The molecular weight determined by a novel LDI MS equipped with a LIFT mode illuminated that polymelem has both linear and cyclic connectivity with a degree of polymerization of 2--5 depending on the synthesis temperature. The decomposition products of polymelem were determined to be cyanoamide, dicyanoamide, and tricyanoamine. Tricyanoamine is the smallest carbon nitride molecule and has been experimentally confirmed for the first time in this study. When polymelem was decomposed in the presence of Raney nickel, homogenous NCNT with nitrogen content of ˜ 4--19 atom% was produced. A mechanism based on a detail analysis of the TEM images at different growth stages proposed that the NCNT propagated via a tip-growth mechanism originating at the nano-domains within the Raney nickel, and was accompanied with the aggregation of the nickel catalysts. Such NCNT exhibited a cup-stack wall structure paired with a compartmental feature. The nitrogen content, tube diameter and wall thickness greatly depended on synthesis conditions. The activated carbon derived from PEEK/PEI blend demonstrated a surface area up to ˜3000 m2/g, and average pore size of < 20 A. Such activated carbon exhibited a hydrogen storage capacity of up to 6.47 wt% at 40 bar, 77 K. The activated carbon has

  1. Activity of catalase adsorbed to carbon nanotubes: effects of carbon nanotube surface properties.

    PubMed

    Zhang, Chengdong; Luo, Shuiming; Chen, Wei

    2013-09-15

    Nanomaterials have been studied widely as the supporting materials for enzyme immobilization. However, the interactions between enzymes and carbon nanotubes (CNT) with different morphologies and surface functionalities may vary, hence influencing activities of the immobilized enzyme. To date how the adsorption mechanisms affect the activities of immobilized enzyme is not well understood. In this study the adsorption of catalase (CAT) on pristine single-walled carbon nanotubes (SWNT), oxidized single-walled carbon nanotubes (O-SWNT), and multi-walled carbon nanotubes (MWNT) was investigated. The adsorbed enzyme activities decreased in the order of O-SWNT>SWNT>MWNT. Fourier transforms infrared spectroscopy (FTIR) and circular dichrois (CD) analyses reveal more significant loss of α-helix and β-sheet of MWNT-adsorbed than SWNT-adsorbed CAT. The difference in enzyme activities between MWNT-adsorbed and SWNT-adsorbed CAT indicates that the curvature of surface plays an important role in the activity of immobilized enzyme. Interestingly, an increase of β-sheet content was observed for CAT adsorbed to O-SWNT. This is likely because as opposed to SWNT and MWNT, O-SWNT binds CAT largely via hydrogen bonding and such interaction allows the CAT molecule to maintain the rigidity of enzyme structure and thus the biological function.

  2. 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.

  3. Breakthrough of toluene vapours in granular activated carbon filled packed bed reactor.

    PubMed

    Mohan, N; Kannan, G K; Upendra, S; Subha, R; Kumar, N S

    2009-09-15

    The objective of this research was to determine the toluene removal efficiency and breakthrough time using commercially available coconut shell-based granular activated carbon in packed bed reactor. To study the effect of toluene removal and break point time of the granular activated carbon (GAC), the parameters studied were bed lengths (2, 3, and 4 cm), concentrations (5, 10, and 15 mg l(-1)) and flow rates (20, 40, and 60 ml/min). The maximum percentage removal of 90% was achieved and the maximum carbon capacity for 5 mg l(-1) of toluene, 60 ml/min flow rate and 3 cm bed length shows 607.14 mg/g. The results of dynamic adsorption in a packed bed were consistent with those of equilibrium adsorption by gravimetric method. The breakthrough time and quantity shows that GAC with appropriate surface area can be utilized for air cleaning filters. The result shows that the physisorption plays main role in toluene removal.

  4. 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...

  5. 40 CFR 60.1820 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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...

  6. 40 CFR 60.1820 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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...

  7. 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? 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...

  8. 40 CFR 60.1820 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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...

  9. The potential application of activated carbon from sewage sludge to organic dyes removal.

    PubMed

    Graham, N; Chen, X G; Jayaseelan, S

    2001-01-01

    The objective of this research work was to study the potential application of activated carbon from sewage sludge to organic dye removal. Methylene blue and crystal violet were the two dyes investigated in the present study. Three activated carbons were produced from the exclusive sewage sludge (referred to as DS), the sludge with the additive of coconut husk (DC) and sludge with the additive of peanut shell (DP) respectively. They were characterized by their surface area and porosity and their surface chemistry structure. Adsorption studies were performed by the batch technique to obtain kinetic and equilibrium data. The results show that the three sludge-derived activated carbons had a developed porosity and marked content of surface functional groups. They exhibited a rapid three-stage adsorption process for both methylene blue and crystal violet. Their adsorption capacities for the two dyes were high, the carbon DP performed best in the adsorption whereas the carbon DC performed worst. It is therefore concluded that the activated carbons made from sewage sludge and its mixtures are promising for dye removal from aqueous streams.

  10. Carbonic anhydrase activators. The selective serotonin reuptake inhibitors fluoxetine, sertraline and citalopram are strong activators of isozymes I and II.

    PubMed

    Casini, Angela; Caccia, Silvio; Scozzafava, Andrea; Supuran, Claudiu T

    2003-08-18

    The selective serotonin reuptake inhibitors (SSRI) fluoxetine, sertraline and citalopram have been investigated for their ability to activate two carbonic anhydrase (CA) isozymes, hCA I and hCA II, in parallel with two standard activators for which the X-ray structure (in complex with isozyme II) has been resolved: histamine and phenylalanine. All three SSRI activated both isozymes with potencies comparable to that of the standards although the profile was different: for hCA I, best activators were fluoxetine and histamine, with citalopram and sertraline showing weaker activity. For hCA II, the best activators were phenylalanine and citalopram, and the weakest histamine and sertraline, whereas fluoxetine showed an intermediate behavior. These results suggest that SSRI efficacy in major depression complicating Alzheimer's disease may be partly due to their ability to activate CA isozymes and may lead to the development of potent activators for the therapy of diseases associated with significant decreases in brain CA activity.

  11. Preparation of Bamboo Chars and Bamboo Activated Carbons to Remove Color and COD from Ink Wastewater.

    PubMed

    Hata, Motohide; Amano, Yoshimasa; Thiravetyan, Paitip; Machida, Motoi

    2016-01-01

    Bamboo chars and bamboo activated carbons prepared by steam activation were applied for ink wastewater treatment. Bamboo char at 800 °C was the best for the removal of color and chemical oxygen demand (COD) from ink wastewater compared to bamboo chars at 300 to 700 °C due to higher surface area and mesopore volume. Bamboo activated carbon at 600 °C (S600) was the best compared to bamboo activated carbon at 800 °C (S800), although S800 had larger surface area (1108 m(2)/g) than S600 (734 m(2)/g). S600 had higher mesopore volume (0.20 cm(3)/g) than S800 (0.16 cm(3)/g) and therefore achieved higher color and COD removal. All bamboo activated carbons showed higher color and COD removal efficiency than commercial activated carbon. In addition, S600 had the superior adsorption capacity for methylene blue (0.89 mmol/g). Therefore, bamboo is a suitable material to prepare adsorbents for removal of organic pollutants.

  12. Physicochemical properties of carbons prepared from pecan shell by phosphoric acid activation.

    PubMed

    Guo, Yanping; Rockstraw, David A

    2007-05-01

    Activated carbons were prepared from pecan shell by phosphoric acid activation. The pore structure and acidic surface groups of these carbons were characterized by nitrogen adsorption, Boehm titration and transmittance Fourier infrared spectroscopy (FTIR) techniques. The characterization results demonstrated that the development of pore structure was apparent at temperatures 250 degrees C, and reached 1130m(2)/g and 0.34cm(3)/g, respectively, at 500 degrees C. Impregnation ratio and soaking time at activation temperature also affected the pore development and pore size distribution of final carbon products. At an impregnation ratio of 1.5, activated carbon with BET surface area and micropore volume as high as 861m(2)/g and 0.289cm(3)/g was obtained at 400 degrees C. Microporous activated carbons were obtained in this study. Low impregnation ratio (less than 1.5) and activation temperature (less than 300 degrees C) are favorable to the formation of acidic surface functional groups, which consist of temperature-sensitive (unstable at high temperature) and temperature-insensitive (stable at high temperature) two parts. The disappearance of temperature-sensitive groups was significant at temperature 300 degrees C; while the temperature-insensitive groups are stable even at 500 degrees C. FTIR results showed that the temperature-insensitive part was mostly phosphorus-containing groups as well as some carbonyl-containing groups, while carbonyl-containing groups were the main contributor of temperature-sensitive part.

  13. Delivery of molecules into cells using carbon nanoparticles activated by femtosecond laser pulses.

    PubMed

    Chakravarty, Prerona; Qian, Wei; El-Sayed, Mostafa A; Prausnitz, Mark R

    2010-08-01

    A major barrier to drug and gene delivery is crossing the cell's plasma membrane. Physical forces applied to cells via electroporation, ultrasound and laser irradiation generate nanoscale holes in the plasma membrane for direct delivery of drugs into the cytoplasm. Inspired by previous work showing that laser excitation of carbon nanoparticles can drive the carbon-steam reaction to generate highly controlled shock waves, we show that carbon black nanoparticles activated by femtosecond laser pulses can facilitate the delivery of small molecules, proteins and DNA into two types of cells. Our initial results suggest that interaction between the laser energy and carbon black nanoparticles may generate photoacoustic forces by chemical reaction to create transient holes in the membrane for intracellular delivery.

  14. 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 ...

  15. Activated carbon injection - a mercury control success story

    SciTech Connect

    2008-07-01

    Almost 100 full-scale activated carbon injection (ACI) systems have been ordered by US electric utilities. These systems have the potential to remove over 90% of the mercury in flue, at a cost below $10,000 per pound of mercury removal. Field trials of ACI systems arm outlined. 1 fig.

  16. Decolorization / deodorization of zein via activated carbons and molecular sieves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective is to evaluate a series of granular media consisting of activated carbons and molecular sieves in a batch process for the purpose of clarifying and removal of color and odor components from yellow zein dispersed in an aqueous alcohol medium. The major contributors of yellow zein is du...

  17. Overview of EPA activities and research related to black carbon

    EPA Science Inventory

    The purpose of this international presentation is to give an overview of EPA activities related to black carbon (BC). This overview includes some summary information on how EPA defines BC, current knowledge on United States emissions and forecasted emission reductions, and ongoin...

  18. Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation.

    PubMed

    Altenor, Sandro; Carene, Betty; Emmanuel, Evens; Lambert, Jacques; Ehrhardt, Jean-Jacques; Gaspard, Sarra

    2009-06-15

    Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, X(P) (gH(3)PO(4)/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000 m(2)/g) and high pore volume (up to 1.19 cm(3)/g) can be obtained. The surface chemical properties of these ACs were investigated by X-ray photoelectron spectroscopy (XPS) and Boehm titration. Their textural and chemical characteristics were compared to those of an AC sample obtained by steam activation of vetiver roots. Classical molecules used for characterizing liquid phase adsorption, phenol and methylene blue (MB), were used. Adsorption kinetics of MB and phenol have been studied using commonly used kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the intraparticle diffusion model and as well the fractal, BWS (Brouers, Weron and Sotolongo) kinetic equation. The correlation coefficients (R(2)) and the normalized standard deviation Deltaq (%) were determined showing globally, that the recently derived fractal kinetic equation could best describe the adsorption kinetics for the adsorbates tested here, indicating a complex adsorption mechanism. The experimental adsorption isotherms of these molecules on the activated carbon were as well analysed using four isotherms: the classical Freundlich, Langmuir, Redlich-Peterson equations, but as well the newly published deformed Weibull Brouers-Sotolongo isotherm. The results obtained from the application of the equations show that the best fits were achieved with the Brouers-Sotolongo equation and with the Redlich-Peterson equation. Influence of surface functional groups towards MB adsorption is as well studied using various ACs prepared from vetiver roots and sugar cane bagasse. Opposite effects governing MB

  19. Activation and micropore structure of carbon-fiber composites

    SciTech Connect

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

    1997-12-01

    Rigid, high surface area activated carbon fiber composites have been produced with high permeabilities for environmental applications in gas and water purification. The project involves a collaboration between the Oak Ridge National Laboratory (ORNL) and the Center for Applied Energy Research (CAER), University of Kentucky. The main focus of recent work has been to find a satisfactory means to uniformly activate large samples of carbon fiber composites to produce controlled pore structures. Processes have been developed using activation in steam and CO{sub 2}, and a less conventional method involving oxygen chemisorption and subsequent heat treatment. Another objective has been to explore applications for the activated composites in environmental applications related to fossil energy production.

  20. An indica rice genotype showed a similar yield enhancement to that of hybrid rice under free air carbon dioxide enrichment

    NASA Astrophysics Data System (ADS)

    Zhu, Chunwu; Xu, Xi; Wang, Dan; Zhu, Jianguo; Liu, Gang

    2015-07-01

    Although the rice growth response to FACE (free-air CO2 enrichment) has been widely studied and is considered important within the scientific community, few studies have attempted to examine the effects of FACE on the yield of indica rice, which is typically the parent of indica hybrids in China. The effects of FACE on the yield, yield components, biomass, N uptake and leaf photosynthesis of Yangdao 6 Hao (an indica rice) in China were examined over 2 years. The grain yield increased over 30%, the panicle number increased 12.4% on average, and the spikelet number per panicle also showed an average increase of 8.2% at elevated CO2. FACE caused a significant enhancement in both the filled spikelet percentage (+5.9%) and the individual grain weight (+3.0%). Compared with three prior FACE studies on rice, a similar enhancement of yield in hybrid indica was shown under FACE, with much a higher value than for the japonica rice cultivar (approximately + 13%) because of indica’s stronger sink generation and N uptake capacity, which help coordinate the C/N balance to avoid photosynthetic acclimation. The high enhancement of the indica rice yield under FACE holds promise for improved cultivar selection for future food security.

  1. Adsorption of cadmium from aqueous solutions on sulfurized activated carbon prepared from nut shells.

    PubMed

    Fouladi Tajar, Amir; Kaghazchi, Tahereh; Soleimani, Mansooreh

    2009-06-15

    Low-cost activated carbon, derived from nut shells, and its modified sample have been used as replacements for the current expensive methods of removing cadmium from aqueous solutions and waste waters. Adsorption of cadmium onto four kinds of activated carbons has been studied; prepared activated carbon (PAC), commercial activated carbon (CAC), and the sulfurized ones (SPAC & SCAC). The activated carbon has been derived, characterized, treated with sulfur and then utilized for the removal of Cd(2+). Sulfurizing agent (SO(2) gas) was successfully used in adsorbents' modification process at the ambient temperature. Samples were then characterized and tested as adsorbents of cadmium. Effect of some parameters such as contact time, initial concentration and pH were examined. With increasing pH, the adsorption of cadmium ions was increased and maximum removal, 92.4% for SPAC, was observed in pH>8.0 (C(0)=100mg/L). The H-type adsorption isotherms, obtained for the adsorbents, indicated a favorable process. Adsorption data on both prepared and commercial activated carbon, before and after sulfurization, followed both the Frendlich and Langmuir models. They were better fitted by Frendlich isotherm as compared to Langmuir. The maximum adsorption capacities were 90.09, 104.17, 126.58 and 142.86 mg/g for CAC, PAC, SCAC and SPAC, respectively. Accordingly, surface modification of activated carbons using SO(2) greatly enhanced cadmium removal. The reversibility of the process has been studied in a qualitative manner and it shows that the spent SPAC can be effectively regenerated for further use easily.

  2. Determining water content in activated carbon for double-layer capacitor electrodes

    NASA Astrophysics Data System (ADS)

    Egashira, Minato; Izumi, Takuma; Yoshimoto, Nobuko; Morita, Masayuki

    2016-09-01

    Karl-Fisher titration is used to estimate water contents in activated carbon and the distribution of impurity-level water in an activated carbon-solvent system. Normalization of the water content of activated carbon is attempted using vacuum drying after immersion in water was controlled. Although vacuum drying at 473 K and 24 h can remove large amounts of water, a substantial amount of water remains in the activated carbon. The water release to propylene carbonate is less than that to acetonitrile. The degradation of capacitor cell capacitance for activated carbon with some amount of water differs according to the electrolyte solvent type: acetonitrile promotes greater degradation than propylene carbonate does.

  3. 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.

  4. Evaluation of the genetic activity of industrially produced carbon black.

    PubMed

    Kirwin, C J; LeBlanc, J V; Thomas, W C; Haworth, S R; Kirby, P E; Thilagar, A; Bowman, J T; Brusick, D J

    1981-06-01

    Commercially produced oil furnace carbon black (Chemical Abstract Service Registry No. 1333-86-4) has been evaluated by five different assay for genetic activity. These were the Ames Salmonella typhimurium reverse mutation test, sister chromatid exchange test in CHO cells, mouse lymphoma test, cell transformation assay in C3H/10T1/2 cells, and assay for genetic effects in Drosophila melanogaster. Limited cellular toxicity was exhibited but no significant genetic activity was noted.

  5. Pecan shell-based granular activated carbon for treatment of chemical oxygen demand (COD) in municipal wastewater.

    PubMed

    Bansode, R R; Losso, J N; Marshall, W E; Rao, R M; Portier, R J

    2004-09-01

    The present investigation was undertaken to compare the adsorption efficiency of pecan shell-based granular activated carbon with the adsorption efficiency of the commercial carbon Filtrasorb 200 with respect to uptake of the organic components responsible for the chemical oxygen demand (COD) of municipal wastewater. Adsorption efficiencies for these two sets of carbons (experimental and commercial) were analyzed by the Freundlich adsorption model. The results indicate that steam-activated and acid-activated pecan shell-based carbons had higher adsorption for organic matter measured as COD, than carbon dioxide-activated pecan shell-based carbon or Filtrasorb 200 at all the carbon dosages used during the experiment. The higher adsorption may be related to surface area as the two carbons with the highest surface area also had the highest organic matter adsorption. These results show that granular activated carbons made from agricultural waste (pecan shells) can be used with greater effectiveness for organic matter removal from municipal wastewater than a coal-based commercial carbon.

  6. Carbon-Based Microbial-Fuel-Cell Electrodes: From Conductive Supports to Active Catalysts.

    PubMed

    Li, Shuang; Cheng, Chong; Thomas, Arne

    2017-02-01

    Microbial fuel cells (MFCs) have attracted considerable interest due to their potential in renewable electrical power generation using the broad diversity of biomass and organic substrates. However, the difficulties in achieving high power densities and commercially affordable electrode materials have limited their industrial applications to date. Carbon materials, which can exhibit a wide range of different morphologies and structures, usually possess physiological activity to interact with microorganisms and are therefore fast-emerging electrode materials. As the anode, carbon materials can significantly promote interfacial microbial colonization and accelerate the formation of extracellular biofilms, which eventually promotes the electrical power density by providing a conductive microenvironment for extracellular electron transfer. As the cathode, carbon-based materials can function as catalysts for the oxygen-reduction reaction, showing satisfying activities and efficiencies nowadays even reaching the performance of Pt catalysts. Here, first, recent advancements on the design of carbon materials for anodes in MFCs are summarized, and the influence of structure and surface functionalization of different types of carbon materials on microorganism immobilization and electrochemical performance is elucidated. Then, synthetic strategies and structures of typical carbon-based cathodes in MFCs are briefly presented. Furthermore, future applications of carbon-electrode-based MFC devices in the energy, environmental, and biological fields are discussed, and the emerging challenges in transferring them from laboratory to industrial scale are described.

  7. 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.

  8. Bimodal activated carbons derived from resorcinol-formaldehyde cryogels

    PubMed Central

    Szczurek, Andrzej; Amaral-Labat, Gisele; Fierro, Vanessa; Pizzi, Antonio; Celzard, Alain

    2011-01-01

    Resorcinol-formaldehyde cryogels prepared at different dilution ratios have been activated with phosphoric acid at 450 °C and compared with their carbonaceous counterparts obtained by pyrolysis at 900 °C. Whereas the latter were, as expected, highly mesoporous carbons, the former cryogels had very different pore textures. Highly diluted cryogels allowed preparation of microporous materials with high surface areas, but activation of initially dense cryogels led to almost non-porous carbons, with much lower surface areas than those obtained by pyrolysis. The optimal acid concentration for activation, corresponding to stoichiometry between molecules of acid and hydroxyl groups, was 2 M l−1, and the acid–cryogel contact time also had an optimal value. Such optimization allowed us to achieve surface areas and micropore volumes among the highest ever obtained by activation with H3PO4, close to 2200 m2 g−1 and 0.7 cm3 g−1, respectively. Activation of diluted cryogels with a lower acid concentration of 1.2 M l−1 led to authentic bimodal activated carbons, having a surface area as high as 1780 m2 g−1 and 0.6 cm3 g−1 of microporous volume easily accessible through a widely developed macroporosity. PMID:27877405

  9. Preparation and characterization of activated carbon fiber (ACF) from cotton woven waste

    NASA Astrophysics Data System (ADS)

    Jieying Zheng; Zhao, Quanlin; Ye, Zhengfang

    2014-04-01

    In this study, the activated carbon fibers (ACFs) were prepared using cotton woven waste as precursor. The cotton woven waste was first partly dissolved by 80% phosphoric acid and then was pre-soaked in 7.5% diammonium hydrogen phosphate solution. Finally, carbonization and activation were proceeded to get ACF. The optimum preparation conditions, including carbonization temperature, carbonization time, activation temperature and activation time, were chosen by orthogonal design. Nitrogen adsorption/desorption test was conducted to characterize the prepared ACF's pore structure. Fourier transform infrared spectroscopy (FTIR) analysis, X-ray photoelectron spectroscopy (XPS) and environmental scanning electron microscope (ESEM) were employed to characterize its chemical properties and morphology. Adsorption of oilfield wastewater was used to evaluate its adsorption properties. The results show that the prepared ACF is in the form of fiber, with the sectional diameters of 11.7 × 2.6 μm and the surface area of 789 m2/g. XPS results show that carbon concentration of the prepared ACF is higher than that of the commercial ACF. When the prepared ACF dosage is 6 g/L, over 80% of COD and over 70% of chrominance can be removed after 24 h of adsorption at 18 °C.

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

    PubMed

    Clack, Herek L

    2012-07-03

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

  11. The benzimidazole based drugs show good activity against T. gondii but poor activity against its proposed enoyl reductase enzyme target.

    PubMed

    Wilkinson, Craig; McPhillie, Martin J; Zhou, Ying; Woods, Stuart; Afanador, Gustavo A; Rawson, Shaun; Khaliq, Farzana; Prigge, Sean T; Roberts, Craig W; Rice, David W; McLeod, Rima; Fishwick, Colin W; Muench, Stephen P

    2014-02-01

    The enoyl acyl-carrier protein reductase (ENR) enzyme of the apicomplexan parasite family has been intensely studied for antiparasitic drug design for over a decade, with the most potent inhibitors targeting the NAD(+) bound form of the enzyme. However, the higher affinity for the NADH co-factor over NAD(+) and its availability in the natural environment makes the NADH complex form of ENR an attractive target. Herein, we have examined a benzimidazole family of inhibitors which target the NADH form of Francisella ENR, but despite good efficacy against Toxoplasma gondii, the IC50 for T. gondii ENR is poor, with no inhibitory activity at 1 μM. Moreover similar benzimidazole scaffolds are potent against fungi which lack the ENR enzyme and as such we believe that there may be significant off target effects for this family of inhibitors.

  12. Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia.

    PubMed

    Vonk, J E; Sánchez-García, L; van Dongen, B E; Alling, V; Kosmach, D; Charkin, A; Semiletov, I P; Dudarev, O V; Shakhova, N; Roos, P; Eglinton, T I; Andersson, A; Gustafsson, O

    2012-09-06

    The future trajectory of greenhouse gas concentrations depends on interactions between climate and the biogeosphere. Thawing of Arctic permafrost could release significant amounts of carbon into the atmosphere in this century. Ancient Ice Complex deposits outcropping along the ~7,000-kilometre-long coastline of the East Siberian Arctic Shelf (ESAS), and associated shallow subsea permafrost, are two large pools of permafrost carbon, yet their vulnerabilities towards thawing and decomposition are largely unknown. Recent Arctic warming is stronger than has been predicted by several degrees, and is particularly pronounced over the coastal ESAS region. There is thus a pressing need to improve our understanding of the links between permafrost carbon and climate in this relatively inaccessible region. Here we show that extensive release of carbon from these Ice Complex deposits dominates (57 ± 2 per cent) the sedimentary carbon budget of the ESAS, the world’s largest continental shelf, overwhelming the marine and topsoil terrestrial components. Inverse modelling of the dual-carbon isotope composition of organic carbon accumulating in ESAS surface sediments, using Monte Carlo simulations to account for uncertainties, suggests that 44 ± 10 teragrams of old carbon is activated annually from Ice Complex permafrost, an order of magnitude more than has been suggested by previous studies. We estimate that about two-thirds (66 ± 16 per cent) of this old carbon escapes to the atmosphere as carbon dioxide, with the remainder being re-buried in shelf sediments. Thermal collapse and erosion of these carbon-rich Pleistocene coastline and seafloor deposits may accelerate with Arctic amplification of climate warming.

  13. 75 FR 48644 - Certain Activated Carbon From the People's Republic of China: Notice of Partial Rescission of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-11

    ... Import Export Corp.; China National Nuclear General Company Ningxia Activated Carbon Factory; Da Neng Zheng Da Activated Carbon Co., Ltd.; Datong Carbon Corporation; Datong Changtai Activated Carbon Co....; DaTong Tri- Star & Power Carbon Plant; Datong Weidu Activated Carbon Co., Ltd.; Datong...

  14. Modeling trapping mechanism for PCB adsorption on activated carbon

    NASA Astrophysics Data System (ADS)

    Jensen, Bjørnar; Kvamme, Bjørn; Kuznetsova, Tatyana; Oterhals, A.˚ge

    2012-12-01

    The levels of polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran (PCDD/F) and dioxin-like polychlorinated biphenyl (DL-PCB) in fishmeal and fish oil produced for use in feed for salmon is above present European legislation levels in some regions of the world and different decontamination approaches have been proposed [1]. One of these is adsorption on activated carbon. This approach appears to be efficient for adsorption of PCDD/F but less efficient for DL-PCB [2]. Activated carbon consists of slit pores with average sizes of 20 - 50 Ångstroms. One hypothesis [2] for the mechanism of trapping DL-PCB is reduced ability for intramolecular movements of the PCB molecules inside the slit pores. In order to investigate this hypothesis we have used quantum mechanics [3] to characterize two DL-PCB congeners, respectively congener 77 (3,3',4,4'-Tetrachlorobiphenyl) and congener 118 (2,3',4,4',5-Pentachlorobiphenyl) and Triolein (18:1) [4] as a major constituent of the solvent fish oil. A model for activated carbon was constructed using a crystal structure of graphite from the American Mineralogist Crystal Structure Database [5]. The crystal structure used was originally from Wyckoff [6]. A small program had to be written to generate the desired graphite structure as it contains no less than 31232 Carbon atoms. Partial atomic charges were estimated using QM with DFT/B3LYP/6-311+g** and SM6 [7].

  15. Livestock air treatment using PVA-coated powdered activated carbon biofilter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficacy of polyvinyl alcohol (PVA) biofilters was studied using bench-scale biofilters and air from aerobically-treated swine manure. The PVA-coated powdered activated carbon particles showed excellent properties as a biofiltration medium: water holding capacity of 1.39 g H2O/g-dry PVA; wet por...

  16. Kinetic effect of Pd additions on the hydrogen uptake of chemically activated, ultramicroporous carbon

    SciTech Connect

    Bhat, Vinay V; Contescu, Cristian I; Gallego, Nidia C

    2010-01-01

    The effect of mixing chemically-activated ultramicroporous carbon (UMC) with Pd nanopowder is investigated. Results show that Pd addition doubles the rate of hydrogen uptake, but does not enhance the hydrogen capacity or improve desorption kinetics. The effect of Pd on the rate of hydrogen adsorption supports the occurrence of the hydrogen spillover mechanism in the Pd - UMC system.

  17. Immobilization of BiOX (X = Cl, Br) on activated carbon fibers as recycled photocatalysts.

    PubMed

    Jiang, Zaiyong; Huang, Baibiao; Lou, Zaizhu; Wang, Zeyan; Meng, Xiaodong; Liu, Yuanyuan; Qin, Xiaoyan; Zhang, Xiaoyang; Dai, Ying

    2014-06-14

    BiOX have been grown on the surface of activated carbon fibers (ACF) as recycled photocatalysts. The analysis results illustrate that electrostatic adsorption plays an important role in the formation of BiOX/ACF composites. The photocatalytic experimental results indicate that BiOX/ACF show excellent cyclic properties and stable performance.

  18. Microporous carbon nanosheets with redox-active heteroatoms for pseudocapacitive charge storage.

    PubMed

    Yun, Y S; Kim, D-H; Hong, S J; Park, M H; Park, Y W; Kim, B H; Jin, H-J; Kang, K

    2015-10-07

    We report microporous carbon nanosheets containing numerous redox active heteroatoms fabricated from exfoliated waste coffee grounds by simple heating with KOH for pseudocapacitive charge storage. We found that various heteroatom combinations in carbonaceous materials can be a redox host for lithium ion storage. The bio-inspired nanomaterials had unique characteristics, showing superior electrochemical performances as cathode for asymmetric pseudocapacitors.

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

    NASA Astrophysics Data System (ADS)

    Werner, David; Han, Zhantao; Karapanagioti, Hrissi

    2014-05-01

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

  20. Adsorption of ethanol onto activated carbon: Modeling and consequent interpretations based on statistical physics treatment

    NASA Astrophysics Data System (ADS)

    Bouzid, Mohamed; Sellaoui, Lotfi; Khalfaoui, Mohamed; Belmabrouk, Hafedh; Lamine, Abdelmottaleb Ben

    2016-02-01

    In this work, we studied the adsorption of ethanol on three types of activated carbon, namely parent Maxsorb III and two chemically modified activated carbons (H2-Maxsorb III and KOH-H2-Maxsorb III). This investigation has been conducted on the basis of the grand canonical formalism in statistical physics and on simplified assumptions. This led to three parameter equations describing the adsorption of ethanol onto the three types of activated carbon. There was a good correlation between experimental data and results obtained by the new proposed equation. The parameters characterizing the adsorption isotherm were the number of adsorbed molecules (s) per site n, the density of the receptor sites per unit mass of the adsorbent Nm, and the energetic parameter p1/2. They were estimated for the studied systems by a non linear least square regression. The results show that the ethanol molecules were adsorbed in perpendicular (or non parallel) position to the adsorbent surface. The magnitude of the calculated adsorption energies reveals that ethanol is physisorbed onto activated carbon. Both van der Waals and hydrogen interactions were involved in the adsorption process. The calculated values of the specific surface AS, proved that the three types of activated carbon have a highly microporous surface.

  1. Properties of pyrolytic chars and activated carbons derived from pilot-scale pyrolysis of used tires.

    PubMed

    Li, S Q; Yao, Q; Wen, S E; Chi, Y; Yan, J H

    2005-09-01

    Used tires were pyrolyzed in a pilot-scale quasi-inert rotary kiln. Influences of variables, such as time, temperature, and agent flow, on the activation of obtained char were subsequently investigated in a laboratory-scale fixed bed. Mesoporous pores are found to be dominant in the pore structures of raw char. Brunauer-Emmett-Teller (BET) surfaces of activated chars increased linearly with carbon burnoff. The carbon burnoff of tire char achieved by carbon dioxide (CO2) under otherwise identical conditions was on average 75% of that achieved by steam, but their BET surfaces are almost the same. The proper activation greatly improved the aqueous adsorption of raw char, especially for small molecular adsorbates, for example, phenol from 6 to 51 mg/g. With increasing burnoff, phenol adsorption exhibited a first-stage linear increase followed by a rapid drop after 30% burnoff. Similarly, iodine adsorption first increased linearly, but it held as the burnoff exceeded 40%, which implied that the reduction of iodine adsorption due to decreasing micropores was partially made up by increasing mesopores. Both raw chars and activated chars showed appreciable adsorption capacity of methylene-blue comparable with that of commercial carbons. Thus, tire-derived activated carbons can be used as an excellent mesoporous adsorbent for larger molecular species.

  2. PERFORMANCE OF ACTIVATED SLUDGE-POWDERED ACTIVATED CARBON-WET AIR REGENERATION SYSTEMS

    EPA Science Inventory

    The investigation summarized in the report was undertaken to evaluate the performance of powdered activated carbon (PAC) technology used in conjunction with wet air regeneration (WAR) at municipal wastewater treatment plants. Excessive ash concentrations accumulated in the mixed ...

  3. Surface Properties and Catalytic Performance of Activated Carbon Fibers Supported TiO2 Photocatalyst

    NASA Astrophysics Data System (ADS)

    Yang, Huifen; Fu, Pingfeng

    Activated carbon fibers supported TiO2 photocatalyst (TiO2/ACF) in felt-form was successfully prepared with a dip-coating process using organic silicon modified acrylate copolymer as a binder followed by calcination at 500°C in a stream of Ar gas. The photocatalyst was characterized by SEM, XRD, XPS, FTIR, and BET surface area. Most of carbon fibers were coated with uniformly distributed TiO2 clusters of nearly 100 nm. The loaded TiO2 layer was particulate for the organic binder in the compact film was carbonized. According to XPS and FTIR analysis, amorphous silica in carbon grains was synthesized after carbonizing organic silicon groups, and the Ti-O-Si bond was formed between the interface of loaded TiO2 and silica. Additionally, the space between adjacent carbon fibers still remained unfilled after TiO2 coating, into which both UV light and polluted solutions could penetrate to form a three-dimensional environment for photocatalytic reactions. While loaded TiO2 amount increased to 456 mg TiO2/1 g ACF, the TiO2/ACF catalyst showed its highest photocatalytic activity, and this activity only dropped about 10% after 12 successive runs, exhibiting its high fixing stability of coated TiO2.

  4. Adsorption of Paraquat dichloride from aqueous solution by activated carbon derived from used tires.

    PubMed

    Hamadi, Nadhem K; Sri Swaminathan; Chen, Xiao Dong

    2004-08-09

    The removal of pesticide from wastewater under different batch experimental conditions, using a car tire derived activated carbon was investigated. The pesticide utilized in the study was Paraquat dichloride (1,1-dimethyl-4,4-bipyridyl dichloride), which is a well known herbicide. The adsorbent was produced from the pyrolysis and activation of used tires (TAC). The performances of this adsorbent and a commercial activated carbon F300 (CAC) have been compared. It was determined that the adsorption of Paraquat was weakly pH dependent. The effects of particle size, carbon dosage, temperature and the initial concentration of the Paraquat were studied. Further experiments investigating the regeneration capabilities of the tire-supplied carbon were performed. The regenerated carbons that were washed with basic pH solution were found to have the best sorption capacity recovery. It was found that the rate of sorption of Paraquat onto the carbon is very fast with almost 90% of the maximum possible adsorption taking place in the first 5 min. Nevertheless, the batch sorption kinetics was fitted for a first-order reversible reaction, a pseudo-first-order reaction and a pseudo-second-order reaction. The pseudo-second-order chemical reaction model appears to provide the best correlation. The applicability of the Langmuir isotherm for the present system has been evaluated at different temperatures. The isotherms show that the sorption capacity of CAC decreases with temperature and the dominant mechanism of CAC adsorption is physical sorption.

  5. Transcription Factor Arabidopsis Activating Factor1 Integrates Carbon Starvation Responses with Trehalose Metabolism.

    PubMed

    Garapati, Prashanth; Feil, Regina; Lunn, John Edward; Van Dijck, Patrick; Balazadeh, Salma; Mueller-Roeber, Bernd

    2015-09-01

    Plants respond to low carbon supply by massive reprogramming of the transcriptome and metabolome. We show here that the carbon starvation-induced NAC (for NO APICAL MERISTEM/ARABIDOPSIS TRANSCRIPTION ACTIVATION FACTOR/CUP-SHAPED COTYLEDON) transcription factor Arabidopsis (Arabidopsis thaliana) Transcription Activation Factor1 (ATAF1) plays an important role in this physiological process. We identified TREHALASE1, the only trehalase-encoding gene in Arabidopsis, as a direct downstream target of ATAF1. Overexpression of ATAF1 activates TREHALASE1 expression and leads to reduced trehalose-6-phosphate levels and a sugar starvation metabolome. In accordance with changes in expression of starch biosynthesis- and breakdown-related genes, starch levels are generally reduced in ATAF1 overexpressors but elevated in ataf1 knockout plants. At the global transcriptome level, genes affected by ATAF1 are broadly associated with energy and carbon starvation responses. Furthermore, transcriptional responses triggered by ATAF1 largely overlap with expression patterns observed in plants starved for carbon or energy supply. Collectively, our data highlight the existence of a positively acting feedforward loop between ATAF1 expression, which is induced by carbon starvation, and the depletion of cellular carbon/energy pools that is triggered by the transcriptional regulation of downstream gene regulatory networks by ATAF1.

  6. Removal of gadolinium-based contrast agents: adsorption on activated carbon.

    PubMed

    Elizalde-González, María P; García-Díaz, Esmeralda; González-Perea, Mario; Mattusch, Jürgen

    2017-01-31

    Three carbon samples were employed in this work, including commercial (1690 m(2) g(-1)), activated carbon prepared from guava seeds (637 m(2) g(-1)), and activated carbon prepared from avocado kernel (1068 m(2) g(-1)), to study the adsorption of the following gadolinium-based contrast agents (GBCAs): gadoterate meglumine Dotarem®, gadopentetate dimeglumine Magnevist®, and gadoxetate disodium Primovist®. The activation conditions with H3PO4 were optimized using a Taguchi methodology to obtain mesoporous materials. The best removal efficiency by square meter in a batch system in aqueous solution and model urine was achieved by avocado kernel carbon, in which mesoporosity prevails over microporosity. The kinetic adsorption curves were described by a pseudo-second-order equation, and the adsorption isotherms in the concentration range 0.5-6 mM fit the Freundlich equation. The chemical characterization of the surfaces shows that materials with a greater amount of phenolic functional groups adsorb the GBCA better. Adsorption strongly depends on the pH due to the combination of the following factors: contrast agent protonated forms and carbon surface charge. The tested carbon samples were able to adsorb 70-90% of GBCA in aqueous solution and less in model urine. This research proposes a method for the elimination of GBCA from patient urine before its discharge into wastewater.

  7. Immobilization of Hg(II) in water with polysulfide-rubber (PSR) polymer-coated activated carbon.

    PubMed

    Kim, Eun-Ah; Seyfferth, Angelia L; Fendorf, Scott; Luthy, Richard G

    2011-01-01

    An effective mercury removal method using polymer-coated activated carbon was studied for possible use in water treatment. In order to increase the affinity of activated carbon for mercury, a sulfur-rich compound, polysulfide-rubber (PSR) polymer, was effectively coated onto the activated carbon. The polymer was synthesized by condensation polymerization between sodium tetrasulfide and 1,2-dichloroethane in water. PSR-mercury interactions and Hg-S bonding were elucidated from x-ray photoelectron spectroscopy, and Fourier transform infra-red spectroscopy analyses. The sulfur loading levels were controlled by the polymer dose during the coating process and the total surface area of the activated carbon was maintained for the sulfur loading less than 2 wt%. Sorption kinetic studies showed that PSR-coated activated carbon facilitates fast reaction by providing a greater reactive surface area than PSR alone. High sulfur loading on activated carbon enhanced mercury adsorption contributing to a three orders of magnitude reduction in mercury concentration. μ-X-ray absorption near edge spectroscopic analyses of the mercury bound to activated carbon and to PSR on activated carbon suggests the chemical bond with mercury on the surface is a combination of Hg-Cl and Hg-S interaction. The pH effect on mercury removal and adsorption isotherm results indicate competition between protons and mercury for binding to sulfur at low pH.

  8. Hierarchical porous carbons prepared by an easy one-step carbonization and activation of phenol-formaldehyde resins with high performance for supercapacitors

    NASA Astrophysics Data System (ADS)

    Zheng, Zhoujun; Gao, Qiuming

    Hierarchical porous carbons are prepared by an easy one-step process of carbonization and activation derived from phenol-formaldehyde resins, in which potassium hydroxide acts as both the catalyst of polymerization and the activation reagent. The simple one-step preparation saves the cost of carbons and leads to high yield. The porous carbons have high surface areas with abundant pore structures. The plenty of micropores and small mesopores increase the capacitance and make the electrolyte ions diffuse fast into the pores. These hierarchical porous carbons show high performance for supercapacitors possessing of the optimized capacitance of 234 F g -1 in aqueous electrolyte and 137 F g -1 in organic electrolyte with high capacitive retention.

  9. Adsorption of Crystal Violet on Activated Carbon Prepared from Coal Flotation Concentrate

    NASA Astrophysics Data System (ADS)

    Aydogmus, Ramazan; Depci, Tolga; Sarikaya, Musa; Riza Kul, Ali; Onal, Yunus

    2016-10-01

    The objective of this study is firstly to investigate the floatability properties of Zilan- Van coal after microwave irradiation and secondly to produce activated carbon from flotation concentrate in order to remove Crystal Violet (CV) from waste water. The flotation experiments showed that microwave heating at 0.9 kW power level for 60 sec exposure time enhanced the hydrophobicity and increased the flotation yield. The activated carbon with remarkable surface area (696 m2/g) was produced from the flotation concentrate and used to adsorb CV from aqueous solution in a batch reactor at different temperature. The adsorption properties of CV onto the activated carbon are discussed in terms of the adsorption isotherms (Langmuir and Freundlich) and found that the experimental results best fitted by the Langmuir model.

  10. Treatment with activated carbon and other adsorbents as an effective method for the removal of volatile compounds in agricultural distillates.

    PubMed

    Balcerek, Maria; Pielech-Przybylska, Katarzyna; Patelski, Piotr; Dziekońska-Kubczak, Urszula; Jusel, Tomaš

    2017-02-08

    This study investigates the effect of treatment with activated carbon and other adsorbents on the chemical composition and organoleptics of a barley malt-based agricultural distillate. Contact with activated carbon is one of the methods by which the quality of raw distillates and spirit beverages can be improved. Samples placed in contact with 1 g activated carbon (SpiritFerm) per 100 ml distillate with ethanol content of 50% v/v for 1 h showed the largest reductions in the concentrations of most volatile compounds (aldehydes, alcohols, esters). Increasing the dose of adsorbent to over 1 g 100 ml(-1) did not improve the purity of the agricultural distillate significantly. Of the tested compounds, acetaldehyde and methanol showed the lowest adsorption on activated carbon. The lowest concentrations of these congeners (expressed in mg l(-1) alcohol 100% v/v) were measured in solutions with ethanol contents of 70-80% v/v, while solutions with an alcoholic strength by volume of 40% did not show statistically significant decreases in these compounds in relation the control sample. The reductions in volatile compounds were compared with those for other adsorbents based on silica or activated carbon and silica. An interesting alternative to activated carbon was found to be an adsorbent prepared from activated carbon and silica (Spiricol). Treatment with this adsorbent produced distillate with the lowest concentrations of acetaldehyde and isovaleraldehyde, and led to the greatest improvement in its organoleptics.

  11. Irreversible adsorption of phenolic compounds by activated carbons

    SciTech Connect

    Grant, T.M.; King, C.J.

    1988-12-01

    Studies were undertaken to determine the reasons why phenolic sorbates can be difficult to remove and recover from activated carbons. The chemical properties of the sorbate and the adsorbent surface, and the influences of changes in the adsorption and desorption conditions were investigated. Comparison of isotherms established after different contact times or at different temperatures indicated that phenolic compounds react on carbon surfaces. The reaction rate is a strong function of temperature. Regeneration of carbons by leaching with acetone recovered at least as much phenol as did regeneration with other solvents or with displacers. The physiochemical properties of adsorbents influences irreversible uptakes. Sorbates differed markedly in their tendencies to undergo irreversible adsorption. 64 refs., 47 figs., 32 tabs.

  12. Structural characteristics of modified activated carbons and adsorption of explosives.

    PubMed

    Tomaszewski, W; Gun'ko, V M; Skubiszewska-Zieba, J; Leboda, R

    2003-10-15

    Several series of activated carbons prepared by catalytic and noncatalytic gasification and subsequent deposition of pyrocarbon by pyrolysis of methylene chloride or n-amyl alcohol were studied by FTIR, chromatography, and adsorption methods using nitrogen and probe organics (explosives). The relationships between the textural characteristics of carbon samples and the recovery rates (eta) of explosives on solid-phase extraction (SPE) using different solvents for their elution after adsorption were analyzed using experimental and quantum chemical calculation results. The eta values for nitrate esters, cyclic nitroamines, and nitroaromatics only partially correlate with different adsorbent parameters (characterizing microporosity, mesoporosity, pore size distributions, etc.), polarity of eluting solvents, or characteristics of probe molecules, since there are many factors strongly affecting the recovery rates. Some of the synthesized carbons provide higher eta values than those for such commercial adsorbents as Hypercarb and Envicarb.

  13. 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.

  14. Enhanced Capacitive Performance of N-Doped Activated Carbon from Petroleum Coke by Combining Ammoxidation with KOH Activation

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Zhang, Yu; Huang, Jufeng; Du, Dongfeng; Xing, Wei; Yan, Zifeng

    2016-05-01

    Low cost with high specific capacitance and energy density is the critical and main requirement for practical supercapacitors. A novel N-doped activated carbon was fabricated by KOH activation of petroleum coke and ammonia treatment. The as-prepared carbon exhibits a high specific surface area (1875 m2 g-1), excellent conductivity (57 S m-1), and rich nitrogen level (4.0 wt%). Those outstanding characters result in this porous carbon a hopeful electrode material for electrochemical supercapacitors. It shows high specific capacitance (up to 299 F g-1) and superior rate capability (76 % retention ratio at 20 A g-1) in 30 wt% KOH aqueous electrolyte. This efficient treatment method ensures its prosperous application in energy storage systems.

  15. Determination of pressure drop across activated carbon fiber respirator cartridges.

    PubMed

    Balanay, Jo Anne G; Lungu, Claudiu T

    2016-01-01

    Activated carbon fiber (ACF) is considered as an alternative adsorbent to granular activated carbon (GAC) for the development of thinner, lighter, and efficient respirators because of their larger surface area and adsorption capacities, thinner critical bed depth, lighter weight, and fabric form. This study aims to measure the pressure drop across different types of commercially available ACFs in respirator cartridges to determine the ACF composition and density that will result in acceptably breathable respirators. Seven ACF types in cloth (ACFC) and felt (ACFF) forms were tested. ACFs in cartridges were challenged with pre-conditioned constant air flow (43 LPM, 23°C, 50% RH) at different compositions (single- or combination-ACF type) in a test chamber. Pressure drop across ACF cartridges were obtained using a micromanometer, and compared among different cartridge configurations, to those of the GAC cartridge, and to the NIOSH breathing resistance requirements for respirator cartridges. Single-ACF type cartridges filled with any ACFF had pressure drop measurements (23.71-39.93 mmH2O) within the NIOSH inhalation resistance requirement of 40 mmH2O, while those of the ACFC cartridges (85.47±3.67 mmH2O) exceeded twice the limit due possibly to the denser weaving of ACFC fibers. All single ACFF-type cartridges had higher pressure drop compared to the GAC cartridge (23.13±1.14 mmH2O). Certain ACF combinations (2 ACFF or ACFC/ACFF types) resulted to pressure drop (26.39-32.81 mmH2O) below the NIOSH limit. All single-ACFF type and all combination-ACF type cartridges with acceptable pressure drop had much lower adsorbent weights than GAC (≤15.2% of GAC weight), showing potential for light-weight respirator cartridges. 100% ACFC in cartridges may result to respirators with high breathing resistance and, thus, is not recommended. The more dense ACFF and ACFC types may still be possibly used in respirators by combining them with less dense ACFF materials and/or by

  16. Adsorption of nitrophenol onto activated carbon: isotherms and breakthrough curves.

    PubMed

    Chern, Jia-Ming; Chien, Yi-Wen

    2002-02-01

    The adsorption isotherm of p-nitrophenol onto granular activated carbon in 25 degrees C aqueous solution was experimentally determined by batch tests. Both the Freundlich and the Redlich-Peterson models were found to fit the adsorption isotherm data well. A series of column tests were performed to determine the breakthrough curves with varying bed depths (3-6 cm) and water flow rates (21.6-86.4 cm3/h). Explicit equations for the breakthrough curves of the fixed-bed adsorption processes with the Langmuir and the Freundlich adsorption isotherms were developed by the constant-pattern wave approach using a constant driving force model in the liquid phase. The results show that the half breakthrough time increases proportionally with increasing bed depth but decreases inverse proportionally with increasing water flow rate. The constant-pattern wave approach using the Freundlich isotherm model fits the experimental breakthrough curves quite satisfactorily. A correlation was proposed to predict the volumetric mass-transfer coefficient in the liquid phase successfully. The effects of solution temperature and pH on the adsorption isotherm were also studied and the Tóth model was found to fit the isotherm data well at varying solution temperatures and pHs.

  17. Regeneration of sulfamethoxazole-saturated activated carbon using gamma irradiation

    NASA Astrophysics Data System (ADS)

    Chu, Libing; Wang, Jianlong

    2017-01-01

    Activated carbon (AC) has been widely used for reclamation and reuse of the effluent of wastewater treatment plant to further remove the emerging contaminants, such as PPCPs in recent years. How to regenerate the exhausted AC effectively and economically is still a challenge. In the present study, the regeneration of AC exhausted with SMX was performed by gamma irradiation to simultaneously recover the spent AC and degrade the pollutants. The results showed that the adsorption of SMX onto AC can be described by the Langmuir isotherm and the adsorption capacity was about 417 mg/g. SMX can be removed rapidly when exposed to gamma irradiation, with the initial concentration of 100 mg/L, more than 99% of SMX was removed at 5.0 kGy, while an extremely high dose (150 kGy) was needed to reach 80% mineralization ratio. The regeneration efficiency was about 21-30% at 50-200 kGy. The absorbed SMX and the intermediates formed during gamma irradiation were released into aqueous solution from AC and mineralized, leading to the partial regeneration of the adsorption capacity of AC. Further studies are needed to optimize the experimental conditions to increase the regeneration efficiency.

  18. Adsorption equilibria of chlorinated organic solvents onto activated carbon

    SciTech Connect

    Yun, J.H.; Choi, D.K.; Kim, S.H.

    1998-04-01

    Adsorption equilibria of dichloromethane, 1,1,1-trichloroethane, and trichloroethylene on activated carbon were obtained by a static volumetric technique. Isotherms were measured for the pure vapors in the temperature range from 283 to 363 K and pressures up to 60 kPa for dichloromethane, 16 kPa for 1,1,1-trichloroethane, and 7 kPa for trichloroethylene, respectively. The Toth and Dubinin-Radushkevich equations were used to correlate experimental isotherms. Thermodynamic properties such as the isosteric heat of adsorption and the henry`s constant were calculated. It was found that the values of isosteric heat of adsorption were varied with surface loading. Also, the Henry`s constant showed that the order of adsorption affinity is 1,1,1-trichloroethane, trichloroethylene, and dichloromethane. By employing the Dubinin-Radushkevich equation, the limiting volume of the adsorbed space, which equals micropore volume, was determined, and its value was found to be approximately independent of adsorbates.

  19. Supporting the process of removing humic substances on activated carbon.

    PubMed

    Olesiak, Paulina; Stępniak, Longina

    2014-01-01

    This study is focused on biosorption process used in water treatment. The process has a number of advantages and a lot of research has been done into its intensification by means of ultrasonic modification of solutions. The study carried out by the authors leads to the conclusion that sonication of organic solutions allows for extension of the time of operation of carbon beds. For the analysis of the results obtained during the sorption of humic substances (HS) from the solution dependencies UV/UV₀ or DOC/DOC₀ were used. In comparative studies the effectiveness of sorption and sonosorption (UV/UV₀) shows that the share of ultrasounds (US) is beneficial for extension of time deposit, both at a flow rate HS solution equal to 1 m/h and 5 m/h. Analysis of the US impact sorption on HS sorption in a biological fluidized bed, both prepared from biopreparat and the activated sludge confirms the higher efficiency compared to sonobiosorption than biosorption. These results confirm the degree of reduction UV₂₅₄/UV₀ and DOC/DOC₀ for the same processes. EMS index also confirms the improvement of HSbiodegradation by sludge microorganisms.

  20. Acoustical evaluation of carbonized and activated cotton nonwovens.

    PubMed

    Jiang, N; Chen, J Y; Parikh, D V

    2009-12-01

    An activated carbon fiber nonwoven (ACF) was manufactured from a cotton nonwoven fabric. For the ACF acoustic 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 glassfiber nonwoven, and the cotton nonwoven base layer with a layer of cotton fiber nonwoven. Their noise absorption coefficients and sound transmission loss were measured using the Brüel and Kjaer impedance tube instrument. Statistical significance of the differences between the composites was tested using the method of Duncan's grouping. The study concluded that the ACF composite exhibited a greater ability to absorb normal incidence sound waves than the composites with either glassfiber or cotton fiber. The analysis of sound transmission loss revealed that the three composites still obeyed the mass law of transmission loss. The composite with the surface layer of cotton fiber nonwoven possessed a higher fabric density and therefore showed a better sound insulation than the composites with glassfiber and ACF.

  1. Nitroimidazoles adsorption on activated carbon cloth from aqueous solution.

    PubMed

    Ocampo-Pérez, R; Orellana-Garcia, F; Sánchez-Polo, M; Rivera-Utrilla, J; Velo-Gala, I; López-Ramón, M V; Alvarez-Merino, M A

    2013-07-01

    The objective of this study was to analyze the equilibrium and adsorption kinetics of nitroimidazoles on activated carbon cloth (ACC), determining the main interactions responsible for the adsorption process and the diffusion mechanism of these compounds on this material. The influence of the different operational variables, such as ionic strength, pH, temperature, and type of water (ultrapure, surface, and waste), was also studied. The results obtained show that the ACC has a high capacity to adsorb nitroimidazoles in aqueous solution. Electrostatic interactions play an important role at pH<3, which favors the repulsive forces between dimetridazole or metronidazole and the ACC surface. The formation of hydrogen bonds and dispersive interactions play the predominant role at higher pH values. Modifications of the ACC with NH3, K2S2O8, and O3 demonstrated that its surface chemistry plays a predominant role in nitroimidazole adsorption on this material. The adsorption capacity of ACC is considerably high in surface waters and reduced in urban wastewater, due to the levels of alkalinity and dissolved organic matter present in the different types of water. Finally, the results of applying kinetic models revealed that the global adsorption rate of dimetridazole and metronidazole is controlled by intraparticle diffusion.

  2. Active carbon filter health condition detection with piezoelectric wafer active sensors

    NASA Astrophysics Data System (ADS)

    Bao, Jingjing; Giurgiutiu, Victor; Rubel, Glenn O.; Peterson, Gregory W.; Ball, Thomas M.

    2011-04-01

    The impregnated active carbon used in air purification systems degrades over time due to exposure to contamination and mechanical effects (packing, settling, flow channeling, etc.). A novel approach is proposed to detect contamination in active carbon filters by combining the electromechanical impedance spectroscopy (EMIS) and electrochemical impedance spectroscopy (ECIS). ECIS is currently being used to evaluate active carbon filtration material; however, it cannot differentiate the impedance changes due to chemical contamination from those due to mechanical changes. EMIS can detect impedance changes due to mechanical changes. For the research work presented in this paper, Piezoelectric wafer active sensor (PWAS) was used for the EMIS method. Some remarkable new phenomena were unveiled in the detection of carbon filter status. 1. PWAS EMIS can detect the presence of contaminants, such as water and kerosene in the carbon bed 2. PWAS EMIS can monitor changes in mechanical pressure that may be associated with carbon bed packing, settling and flow channeling 3. EMIS and ECIS measurements are consistent with each other and complimentary A tentative simplified impedance model was created to simulate the PWAS-carbon bed system under increasing pressure. Similar impedance change pattern was observed when comparing the simulation results with experimental data.

  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. A method for preparing ferric activated carbon composites adsorbents to remove arsenic from drinking water.

    PubMed

    Zhang, Qiao Li; Lin, Y C; Chen, X; Gao, Nai Yun

    2007-09-30

    Iron oxide/activated carbon (FeO/AC) composite adsorbent material, which was used to modify the coal-based activated carbon (AC) 12 x 40, was prepared by the special ferric oxide microcrystal in this study. This composite can be used as the adsorbent to remove arsenic from drinking water, and Langmuir isotherm adsorption equation well describes the experimental adsorption isotherms. Then, the arsenic desorption can subsequently be separated from the medium by using a 1% aqueous NaOH solution. The apparent characters and physical chemistry performances of FeO/AC composite were investigated by X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Batch and column adsorption experiments were carried out to investigate and compare the arsenic removal capability of the prepared FeO/AC composite material and virgin activated carbon. It can be concluded that: (1) the main phase present in this composite are magnetite (Fe(3)O(4)), maghemite (gamma-Fe(2)O(3)), hematite (alpha-Fe(2)O(3)) and goethite (alpha-FeO(OH)); (2) the presence of iron oxides did not significantly affect the surface area or the pore structure of the activated carbon; (3) the comparisons between the adsorption isotherms of arsenic from aqueous solution onto the composite and virgin activated carbon showed that the FeO/AC composite behave an excellent capacity of adsorption arsenic than the virgin activated carbon; (4) column adsorption experiments with FeO/AC composite adsorbent showed that the arsenic could be removed to below 0.01 mg/L within 1250 mL empty bed volume when influent concentration was 0.5mg/L.

  5. Branched pore kinetic model analysis of geosmin adsorption on super-powdered activated carbon.

    PubMed

    Matsui, Yoshihiko; Ando, Naoya; Sasaki, Hiroshi; Matsushita, Taku; Ohno, Koichi

    2009-07-01

    Super-powdered activated carbon (S-PAC) is activated carbon of much finer particle size than powdered activated carbon (PAC). Geosmin is a naturally occurring taste and odor compound that impairs aesthetic quality in drinking water. Experiments on geosmin adsorption on S-PAC and PAC were conducted, and the results using adsorption kinetic models were analyzed. PAC pulverization, which produced the S-PAC, did not change geosmin adsorption capacity, and geosmin adsorption capacities did not differ between S-PAC and PAC. Geosmin adsorption kinetics, however, were much higher on S-PAC than on PAC. A solution to the branched pore kinetic model (BPKM) was developed, and experimental adsorption kinetic data were analyzed by BPKM and by a homogeneous surface diffusion model (HSDM). The HSDM describing the adsorption behavior of geosmin required different surface diffusivity values for S-PAC and PAC, which indicated a decrease in surface diffusivity apparently associated with activated carbon particle size. The BPKM, consisting of macropore diffusion followed by mass transfer from macropore to micropore, successfully described the batch adsorption kinetics on S-PAC and PAC with the same set of model parameter values, including surface diffusivity. The BPKM simulation clearly showed geosmin removal was improved as activated carbon particle size decreased. The simulation also implied that the rate-determining step in overall mass transfer shifted from intraparticle radial diffusion in macropores to local mass transfer from macropore to micropore. Sensitivity analysis showed that adsorptive removal of geosmin improved with decrease in activated carbon particle size down to 1microm, but further particle size reduction produced little improvement.

  6. Characterization and Properties of Activated Carbon Prepared from Tamarind Seeds by KOH Activation for Fe(III) Adsorption from Aqueous Solution.

    PubMed

    Mopoung, Sumrit; Moonsri, Phansiri; Palas, Wanwimon; Khumpai, Sataporn

    2015-01-01

    This research studies the characterization of activated carbon from tamarind seed with KOH activation. The effects of 0.5 : 1-1.5 : 1 KOH : tamarind seed charcoal ratios and 500-700°C activation temperatures were studied. FTIR, SEM-EDS, XRD, and BET were used to characterize tamarind seed and the activated carbon prepared from them. Proximate analysis, percent yield, iodine number, methylene blue number, and preliminary test of Fe(III) adsorption were also studied. Fe(III) adsorption was carried out by 30 mL column with 5-20 ppm Fe(III) initial concentrations. The percent yield of activated carbon prepared from tamarind seed with KOH activation decreased with increasing activation temperature and impregnation ratios, which were in the range from 54.09 to 82.03 wt%. The surface functional groups of activated carbon are O-H, C=O, C-O, -CO3, C-H, and Si-H. The XRD result showed high crystallinity coming from a potassium compound in the activated carbon. The main elements found in the activated carbon by EDS are C, O, Si, and K. The results of iodine and methylene blue adsorption indicate that the pore size of the activated carbon is mostly in the range of mesopore and macropore. The average BET pore size and BET surface area of activated carbon are 67.9764 Å and 2.7167 m(2)/g, respectively. Finally, the tamarind seed based activated carbon produced with 500°C activation temperature and 1.0 : 1 KOH : tamarind seed charcoal ratio was used for Fe(III) adsorption test. It was shown that Fe(III) was adsorbed in alkaline conditions and adsorption increased with increasing Fe(III) initial concentration from 5 to 20 ppm with capacity adsorption of 0.0069-0.019 mg/g.

  7. [Removal of fluorescent whitening agent by hydrogen peroxide oxidation catalyzed by activated carbon].

    PubMed

    Liu, Hai-Long; Zhang, Zhong-Min; Zhao, Xia; Jiao, Ru-Yuan

    2014-06-01

    Degradation of fluorescent whitening agent VBL in the processes of activated carbon (AC) and activated carbon modified (ACM) adsorptions, hydrogen peroxide (H2O2) oxidation, and hydrogen peroxide oxidation catalyzed by activated carbon were studied. Mechanism of the above catalytic oxidation was also investigated by adding tert-Butyl alcohol (TBA), the free radical scavenger, and detecting the released gases. The results showed that: the activated carbon modified by Fe (NO3)3 (ACM)exhibited better adsorption removal than AC. Catalytic oxidation showed efficient removal of VBL, and the catalytic removal of AC (up to 95%) was significantly higher than that of ACM (58% only). Catalytic oxidation was inhibited by TBA, which indicates that the above reaction involved *OH radicals and atom oxygen generated by hydrogen peroxide with the presence of AC. The results of H2O2 decomposition and released gases detection involved in the process showed that activated carbon enhanced the decomposition of H2O2 which released oxygen and heat. More O2 was produced and higher temperature of the reactor was achieved, which indicated that H2O2 decomposition catalyzed by ACM was significantly faster than that of AC. Combining the results of VBL removal, it could be concluded that the rate of active intermediates (*OH radicals and atom oxygen) production by ACM catalytic reaction was faster than that of AC. These intermediates consumed themselves and produced O2 instead of degrading VBL. It seemed that the improper mutual matching of the forming rate of activating intermediates and the supply rate of reactants was an important reason for the lower efficiency of ACM catalytic reaction comparing with AC.

  8. Preparation and characterization activated carbon from rice husk and oil palm empty fruit bunches for removal of Zn2+ in aqueous solution

    NASA Astrophysics Data System (ADS)

    Ismail, Nur Enzati Afwana; Taha, Mohd F.; Ramli, Anita

    2016-11-01

    The ability of activated carbon prepared from rice husk (RH), oil palm empty fruit bunches (EFB) and mixture (Mix) activated carbon in adsorption of Zinc (Zn2+) from aqueous solution was investigated. The Mix activated carbon has prepared from mixture of RH and EFB activated carbon with weight ratio (1:1) The RH and EFB activated carbon were produced by using sodium hydroxide (NaOH) as a dehydrating agent in chemical activation process.EFB activated carbon showed excellent efficiency in removing Zn2+ with their percentage removal up to 100% even at low adsorbent dosage. The study also showed that the adsorption of Zn2+ by EFB, RH and Mix activated carbon is dependent on the adsorbent dosage and initial metal concentration. The adsorption isotherms of the Zn2+ of EFB, RH and Mix activated carbon were determined and compared with Langmuir and Freundlich models. It was showed that Langmuir model was more favorable for RH and Mix activated carbon with correlation coefficient (R2) value is 0.9958 and 0.9847. In contrast, EFB activated carbon was more favorable to the Freundlich and Langmuir model with correlation coefficient (R2) are 0.9967 and 0.9967

  9. Removal of lead from aqueous solution by activated carbon prepared from Enteromorpha prolifera by zinc chloride activation.

    PubMed

    Li, Yanhui; Du, Qiuju; Wang, Xiaodong; Zhang, Pan; Wang, Dechang; Wang, Zonghua; Xia, Yanzhi

    2010-11-15

    Activated carbon was prepared from Enteromorpha prolifera (EP) by zinc chloride activation. The physico-chemical properties of EP-activated carbon (EPAC) were characterized by thermal stability, zeta potential and Boehm titration methods. The examination showed that EPAC has a porous structure with a high surface area of 1688 m(2)/g. Batch adsorption experiments were carried out to study the effect of various parameters such as initial pH, adsorbent dosage, contact time and temperature on Pb(II) ions adsorption properties by EPAC. The kinetic studies showed that the adsorption data followed a pseudo second-order kinetic model. The isotherm analysis indicated that the adsorption data can be represented by Freundlich isotherm model. Thermodynamic studies indicated that the adsorption reaction was a spontaneous and endothermic process.

  10. Carbon nanotubes-dispersed TiO{sub 2} nanoparticles with their enhanced photocatalytic activity

    SciTech Connect

    Liu, Bo; Xu, Youfeng; Cui, Jing; Wang, Sheng; Wang, Tao

    2014-11-15

    Graphical abstract: Carbon nanotubes-dispersed TiO{sub 2} nanoparticles with their enhanced photocatalytic activity. - Abstract: A novel carbon nanotubes (CNTs)-dispersed route is used to prepare high-activity titanium dioxide nanoparticles (TiO{sub 2}). Field-emission scanning electron microscopy and transmission electron microscopy reveals that the irregular TiO{sub 2} nanoparticles with diameters of 10–20 nm are highly dispersed. X-ray diffraction and specific surface area measurement show that high-activity anatase crystal is formed and the specific surface area of TiO{sub 2} nanoparticles is 147.36 m{sup 2}/g. The photoactivity of TiO{sub 2} was tested by photodegradation of Rhodamine B. The result shows that the photocatalytic activity of TiO{sub 2} nanoparticles prepared by the CNTs-dispersed route is three times higher than that by conventional hydrothermal treatment.

  11. Synthesis and Antioxidant Activity of Hydroxytyrosol Alkyl-Carbonate Derivatives.

    PubMed

    Fernandez-Pastor, Ignacio; Fernandez-Hernandez, Antonia; Rivas, Francisco; Martinez, Antonio; Garcia-Granados, Andres; Parra, Andres

    2016-07-22

    Three procedures have been investigated for the isolation of tyrosol (1) and hydroxytyrosol (2) from a phenolic extract obtained from the solid residue of olive milling. These three methods, which facilitated the recovery of these phenols, were chemical or enzymatic acetylation, benzylation, and carbomethoxylation, and subsequent carbonylation or acetonation reactions. Several new lipophilic alkyl-carbonate derivatives of hydroxytyrosol have been synthesized, coupling the primary hydroxy group of this phenol, through a carbonate linker, using alcohols with different chain lengths. The antioxidant properties of these lipophilic derivatives have been evaluated by different methods and compared with free hydroxytyrosol (2) and also with the well-known antioxidants BHT and α-tocopherol. Three methods were used for the determination of this antioxidant activity: FRAP and ABTS assays, to test the antioxidant power in hydrophilic media, and the Rancimat test, to evaluate the antioxidant capacity in a lipophilic matrix. These new alkyl-carbonate derivatives of hydroxytyrosol enhanced the antioxidant activity of this natural phenol, with their antioxidant properties also being higher than those of the commercial antioxidants BHT and α-tocopherol. There was no clear influence of the side-chain length on the antioxidant properties of the alkyl-carbonate derivatives of 2, although the best results were achieved mainly by the compounds with a longer chain on the primary hydroxy group of this natural phenolic substance.

  12. 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.

  13. Decomposition of adsorbed VX on activated carbons studied by 31P MAS NMR.

    PubMed

    Columbus, Ishay; Waysbort, Daniel; Shmueli, Liora; Nir, Ido; Kaplan, Doron

    2006-06-15

    The fate of the persistent OP nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX) on granular activated carbons that are used for gas filtration was studied by means of 31P magic angle spinning (MAS) NMR spectroscopy. VX as vapor or liquid was adsorbed on carbon granules, and MAS NMR spectra were recorded periodically. The results show that at least 90% of the adsorbed VX decomposes within 20 days or less to the nontoxic ethyl methylphosphonic acid (EMPA) and bis(S-2-diisopropylaminoethane) {(DES)2}. Decomposition occurred irrespective of the phase from which VX was loaded, the presence of metal impregnation on the carbon surface, and the water content of the carbon. Theoretical and practical aspects of the degradation are discussed.

  14. Adsorption of polychlorinated dibenzo-p-dioxins/dibenzofurans on activated carbon from hexane.

    PubMed

    Zhou, Xu-Jian; Buekens, Alfons; Li, Xiao-Dong; Ni, Ming-Jiang; Cen, Ke-Fa

    2016-02-01

    Activated carbon is widely used to abate dioxins and dioxin-like compounds from flue gas. Comparing commercial samples regarding their potential to adsorb dioxins may proceed by using test columns, yet it takes many measurements to characterise the retention and breakthrough of dioxins. In this study, commercial activated carbon samples are evaluated during tests to remove trace amounts of dioxins dissolved in n-hexane. The solution was prepared from fly ash collected from a municipal solid waste incinerator. The key variables selected were the concentration of dioxins in n-hexane and the dosage of activated carbon. Both polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) showed very high removal efficiencies (94.7%-98.0% for PCDDs and 99.7%-99.8% for PCDFs). The presence of a large excess of n-hexane solvent had little effect on the removal efficiency of PCDD/Fs. The adsorbed PCDD/Fs showed a linear correlation (R(2) > 0.98) with the initial concentrations. Comparative analysis of adsorption isotherms showed that a linear Henry isotherm fitted better the experimental data (R(2) = 0.99 both for PCDDs and PCDFs) than the more usual Freundlich isotherm (R(2) = 0.88 for PCDDs and 0.77 for PCDFs). Finally, the results of fingerprint analysis indicated that dioxin fingerprint (weight proportion of different congeners) on activated carbon after adsorption did not change from that in hexane.

  15. Optimization of Neutron Activation of Carbon at the NIF

    NASA Astrophysics Data System (ADS)

    Padalino, S.; Polsin, D.; Russ, M.; Sangster, T.; LLE Collaboration

    2011-10-01

    To determine the rhoR of ignition scale targets at the NIF, a carbon activation diagnostic is being developed to measure tertiary neutron yield. It has been shown theoretically that the ratio of the tertiary yield to the primary yield is directly related to rhoR and is nearly independent of hot-spot electron temperature. Due to carbon's 20.3 MeV reaction threshold, it is insensitive to 14.7 MeV primary neutrons which are measured by other means and allows for an unambiguous determination of the tertiary to primary ratio. The energy distribution of the 20 to 30 MeV DT neutrons folded with the (n,2n) cross section in this energy region determines the degree in which carbon will be activated. However, the published 12C(n,2n) cross sections in this energy range are bifurcated. To set upper and lower limits on the sensitivity of the activation diagnostic, a finite element calculation was used to determine the limits of the method's usefulness at differing primary yields and solid angles for the NIF chamber. It was further used to verify MCNPX activation calculations. This work was funded in part by the USDOE through LLE.

  16. 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.

  17. Iron oxide nanoparticles embedded in activated carbons prepared from hydrothermally treated waste biomass.

    PubMed

    Hao, Wenming; Björkman, Eva; Yun, Yifeng; Lilliestråle, Malte; Hedin, Niklas

    2014-03-01

    Particles of iron oxide (Fe3O4 ; 20–40 nm) were embedded within activated carbons during the activation of hydrothermally carbonized (HTC) biomasses in a flow of CO2. Four different HTC biomass samples (horse manure, grass cuttings, beer production waste, and biosludge) were used as precursors for the activated carbons. Nanoparticles of iron oxide formed from iron catalyst included in the HTC biomasses. After systematic optimization, the activated carbons had specific surface areas of about 800 m2g1. The pore size distributions of the activated carbons depended strongly on the degree of carbonization of the precursors. Activated carbons prepared from highly carbonized precursors had mainly micropores, whereas those prepared from less carbonized precursors contained mainly mesopores. Given the strong magnetism of the activated carbon–nano-Fe3O4 composites, they could be particularly useful for water purification.

  18. Synthesis, characterization and catalytic activity of carbon-silica hybrid catalyst from rice straw

    NASA Astrophysics Data System (ADS)

    Janaun, J.; Safie, N. N.; Siambun, N. J.

    2016-07-01

    The hybrid-carbon catalyst has been studied because of its promising potential to have high porosity and surface area to be used in biodiesel production. Silica has been used as the support to produce hybrid carbon catalyst due to its mesoporous structure and high surface area properties. The chemical synthesis of silica-carbon hybrid is expensive and involves more complicated preparation steps. The presence of natural silica in rice plants especially rice husk has received much attention in research because of the potential as a source for solid acid catalyst synthesis. But study on rice straw, which is available abundantly as agricultural waste is limited. In this study, rice straw undergone pyrolysis and functionalized using fuming sulphuric acid to anchor -SO3H groups. The presence of silica and the physiochemical properties of the catalyst produced were studied before and after sulphonation. The catalytic activity of hybrid carbon silica acid catalyst, (H-CSAC) in esterification of oleic acid with methanol was also studied. The results showed the presence of silica-carbon which had amorphous structure and highly porous. The carbon surface consisted of higher silica composition, had lower S element detected as compared to the surface that had high carbon content but lower silica composition. This was likely due to the fact that Si element which was bonded to oxygen was highly stable and unlikely to break the bond and react with -SO3H ions. H-CSAC conversions were 23.04 %, 35.52 % and 34.2 7% at 333.15 K, 343.15 K and 353.15 K, respectively. From this research, rice straw can be used as carbon precursor to produce hybrid carbon-silica catalyst and has shown catalytic activity in biodiesel production. Rate equation obtained is also presented.

  19. Scalable synthesis of hierarchical macropore-rich activated carbon microspheres assembled by carbon nanoparticles for high rate performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Zhang, Dongdong; Zhao, Jianghong; Feng, Chong; Zhao, Rijie; Sun, Yahui; Guan, Taotao; Han, Baixin; Tang, Nan; Wang, Jianlong; Li, Kaixi; Qiao, Jinli; Zhang, Jiujun

    2017-02-01

    A scalable inverse-microemulsion-polymerization-phase-separation coupling method is applied to successfully prepare hierarchical macropore-rich activated carbon microspheres (ACS) using a phenolic resin (PR) precursor followed by carbonization and KOH activation for the first time. The formed ACS materials are assembled by carbon nanoparticles (CNPs). The macropores interspersed among the component CNPs are formed after removing the non-reactive solvent phase in the course of the polymerization of the reactive PR phase, which occupies ∼64% of the total pore volume (∼2.779 cm3 g-1) of the optimized ACS. In combination with mesopores (∼18% of the total pore volume), the ACS possesses meso/macropores approaching 82% of the total pore volume. Micropores are created in the component CNPs via KOH activation, showing shortened ion transport distances in the nanoscale dimension. Both the hierarchical micro/meso/macroporous structure and the inner nanoparticle morphology (short ion diffusion pathways) can significantly contribute to the rapid transport of electrolyte ions throughout the carbonaceous matrix, resulting in superior rate performance of ACS-based supercapacitors. More importantly, the energy densities of the ACS supercapacitors operating in both aqueous and organic electrolyte retain steady over a wide range of power densities varying dramatically from 0.25 to 14.5 kW kg-1 and to 7.0 kW kg-1, respectively.

  20. Degradation characteristics of 17beta-estradiol by ozone treatment with activated carbon.

    PubMed

    Kawasaki, Naohito; Ogata, Fumihiko; Yamaguchi, Isao; Tominaga, Hisato

    2009-01-01

    The present study investigates (1) ozone treatment, (2) adsorption treatment using activated carbon treatment, and (3) ozone treatment with activated carbon for their efficacy in removing 17beta-estradiol (E2) present in an aqueous solution. Both ozone and activated carbon treatments for 20 min were effective in removing E2 (initial concentration, 100 mg/L). However, both treatments have been used for two processes, and the disposal time with these treatments is more than that of another treatment. In this study, ozone treatment with activated carbon was investigated with regard to the percentage of E2 removal, pH, and chemical oxygen demand (COD). The physical and chemical characteristics of the activated carbon surface were modified due to the ozone treatment: the surface was oxidized by ozone. The surface of activated carbon exhibited polarity groups and became porous after ozone treatment. The amount of E2 adsorbed onto the ozone-treated activated carbon surface was similar to that adsorbed onto the untreated activated carbon surface. The percentage of E2 removal by ozone treatment with activated carbon was greater than that by ozone treatment alone. Moreover, the rate of E2 removal by ozone treatment with activated carbon was higher than that by ozone or activated carbon treatments alone. Ozone with activated carbon treatment may be used for the removal of E2. However, this ozone treatment for the degradation of E2 may have a greater COD than that in the case of activated carbon treatment alone.

  1. Effect of activated carbon on microbial bioavailability of phenanthrene in soils

    SciTech Connect

    Yang, Y.; Hunter, W.; Tao, S.; Crowley, D.; Gan, J.

    2009-11-15

    Bioavailability is a governing factor that controls the rate of biological degradation of hydrophobic organic contaminants in soil. Among the solid phases that can adsorb hydrophobic organic contaminants in soil, black carbon (BC) exerts a particularly significant effect on phase distribution. However, knowledge on the effect of BC on the microbial availability of polycyclic aromatic hydrocarbons in soil is still limited. In the present study, the effect of a coal-derived activated carbon on the bioavailability of phenanthrene (PHE) during its degradation by Mycobacterium vanbaalenii PYR-1 was measured in three soils. The freely dissolved concentration of PHE was concurrently determined in soil solutions using disposable polydimethylsiloxane fibers. The results showed that PHE mineralization was significantly inhibited after addition of activated carbon in all test soils. After 216 h, only 5.20, 5.83, and 6.85% of PHE was degraded in the 0.5% BC-amended soils initially containing organic carbon at 0.23, 2.1, and 7.1%, respectively. Significant correlation was found between PHE degradability and freely dissolved concentration, suggesting that BC affected PHE bioavailability by decreasing chemical activity. The effect of activated carbon in the amended soils was attributed to its enhancement of soil surface areas and pore volumes. Results from the present study clearly highlighted the importance of BC for influencing the microbial availability of polycyclic aromatic hydrocarbons in soils.

  2. A comparison of different activated carbon performances on catalytic ozonation of a model azo reactive dye.

    PubMed

    Gül, S; Eren, O; Kır, S; Onal, Y

    2012-01-01

    The objective of this study is to compare the performances of catalytic ozonation processes of two activated carbons prepared from olive stone (ACOS) and apricot stone (ACAS) with commercial ones (granular activated carbon-GAC and powder activated carbon-PAC) in degradation of reactive azo dye (Reactive Red 195). The optimum conditions (solution pH and amount of catalyst) were investigated by using absorbencies at 532, 220 and 280 nm wavelengths. Pore properties of the activated carbon (AC) such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N(2) adsorption. The highest BET surface area carbon (1,275 m(2)/g) was obtained from ACOS with a particle size of 2.29 nm. After 2 min of catalytic ozonation, decolorization performances of ACOS and ACAS (90.4 and 91.3%, respectively) were better than that of GAC and PAC (84.6 and 81.2%, respectively). Experimental results showed that production of porous ACs with high surface area from olive and apricot stones is feasible in Turkey.