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Sample records for activated carbon amendment

  1. Biological uptake of polychlorinated biphenyls by Macoma balthica from sediment amended with activated carbon

    USGS Publications Warehouse

    McLeod, Pamela B.; van den Heuvel-Greve, Martine J.; Luoma, S.N.; Luthy, R.G.

    2007-01-01

    This work characterizes the efficacy of activated carbon amendment in reducing polychlorinated biphenyl (PCB) bioavailability to clams (Macoma balthica) from field-contaminated sediment (Hunters Point Naval Shipyard, San Francisco Bay, CA, USA) Test methods were developed for the use of clams to investigate the effects of sediment amendment on biological uptake. Sediment was mixed with activated carbon for one month. Bioaccumulation tests (28 d) were employed to assess the relationships between carbon dose and carbon particle size on observed reductions in clam biological uptake of PCBs. Extraction and cleanup protocols were developed for the clam tissue. Efficacy of activated carbon treatment was found to increase with both increasing carbon dose and decreasing carbon particle size. Average reductions in bioaccumulation of 22, 64, and 84% relative to untreated Hunters Point sediment were observed for carbon amendments of 0.34, 1.7, and 3.4%, respectively. Average bioaccumulation reductions of 41, 73, and 89% were observed for amendments (dose = 1.7% dry wt) with carbon particles of 180 to 250, 75 to 180, and 25 to 75 ??m, respectively, in diameter, indicating kinetic phenomena in these tests. Additionally, a biodynamic model quantifying clam PCB uptake from water and sediment as well as loss through elimination provided a good fit of experimental data. Model predictions suggest that the sediment ingestion route contributed 80 to 95% of the PCB burdens in the clams. ?? 2007 SETAC.

  2. Iron Amendment and Fenton Oxidation of MTBE-Spent Granular Activated Carbon

    EPA Science Inventory

    Fenton-driven regeneration of Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves Fe amendment to the GAC to catalyze H2O2 reactions and to enhance the rate of MTBE oxidation and GAC regeneration. Four forms of iron (ferric sulfate, ferric chloride, fer...

  3. Impacts of Activated Carbon Amendment on Hg Methylation, Demethylation and Microbial Activity in Marsh Soils

    NASA Astrophysics Data System (ADS)

    Gilmour, C. C.; Ghosh, U.; Santillan, E. F. U.; Soren, A.; Bell, J. T.; Butera, D.; McBurney, A. W.; Brown, S.; Henry, E.; Vlassopoulos, D.

    2015-12-01

    In-situ sorbent amendments are a low-impact approach for remediation of contaminants in sediments, particular in habitats like wetlands that provide important ecosystem services. Laboratory microcosm trials (Gilmour et al. 2013) and early field trials show that activated carbon (AC) can effectively increase partitioning of both inorganic Hg and methylmercury to the solid phase. Sediment-water partitioning can serve as a proxy for Hg and MeHg bioavailability in soils. One consideration in using AC in remediation is its potential impact on organisms. For mercury, a critical consideration is the potential impact on net MeHg accumulation and bioavailability. In this study, we specifically evaluated the impact of AC on rates of methylmercury production and degradation, and on overall microbial activity, in 4 different Hg-contaminated salt marsh soils. The study was done over 28 days in anaerobic, sulfate-reducing slurries. A double label of enriched mercury isotopes (Me199Hg and inorganic 201Hg) was used to separately follow de novo Me201Hg production and Me199Hg degradation. AC amendments decreased both methylation and demethylation rate constants relative to un-amended controls, but the impact on demethylation was stronger. The addition of 5% (dry weight) regenerated AC to soil slurries drove demethylation rate constants to nearly zero; i.e. MeHg sorption to AC almost totally blocked its degradation. The net impact was increased solid phase MeHg concentrations in some of the soil slurries with the highest methylation rate constants. However, the net impact of AC amendments was to increase MeHg (and inorganic Hg) partitioning to the soil phase and decrease concentrations in the aqueous phase. AC significantly decreased aqueous phase inorganic Hg and MeHg concentrations after 28 days. Overall, the efficacy of AC in reducing aqueous MeHg was highest in the soils with the highest MeHg concentrations. The AC addition did not significantly impact microbial activity, as

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

    PubMed

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

    2013-07-01

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

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

    NASA Astrophysics Data System (ADS)

    Werner, David; Meynet, Paola; Bushnaf, Khaled

    2013-04-01

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

  6. 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.

  7. Short-term effect of the soil amendments activated carbon, biochar, and ferric oxyhydroxide on bacteria and invertebrates.

    PubMed

    Hale, Sarah E; Jensen, John; Jakob, Lena; Oleszczuk, Patryk; Hartnik, Thomas; Henriksen, Thomas; Okkenhaug, Gudny; Martinsen, Vegard; Cornelissen, Gerard

    2013-08-06

    The aim of the present study was to evaluate the secondary ecotoxicological effects of soil amendment materials that can be added to contaminated soils in order to sequester harmful pollutants. To this end, a nonpolluted agricultural soil was amended with 0.5, 2, and 5% of the following four amendments: powder activated carbon (PAC), granular activated carbon, corn stover biochar, and ferric oxyhydroxide powder, which have previously been proven to sequester pollutants in soil. The resulting immediate effects (i.e., without aging the mixtures before carrying out tests) on the springtail Folsomia candida, the earthworm species Aporectodea caliginosa and Eisenia fetida, the marine bacteria Vibrio fischeri, a suite of ten prokaryotic species, and a eukaryote (the yeast species Pichia anomalia) were investigated. Reproduction of F. candida was significantly increased compared to the unamended soil when 2% biochar was added to it. None of the treatments caused a negative effect on reproduction. All amendments had a deleterious effect on the growth of A. caliginosa when compared to the unamended soil, except the 0.5% amendment of biochar. In avoidance tests, E. fetida preferred biochar compared to all other amendments including the unamended soil. All amendments reduced the inhibition of luminescence to V. fischeri, i.e., were beneficial for the bacteria, with PAC showing the greatest improvement. The effects of the amendments on the suite of prokaryotic species and the eukaryote were variable, but overall the 2% biochar dose provided the most frequent positive effect on growth. It is concluded that the four soil amendments had variable but never strongly deleterious effects on the bacteria and invertebrates studied here during the respective recommended experimental test periods.

  8. Measuring and Modeling Organochlorine Pesticide Response to Activated Carbon Amendment in Tidal Sediment Mesocosms.

    PubMed

    Thompson, Jay M; Hsieh, Ching-Hong; Hoelen, Thomas P; Weston, Donald P; Luthy, Richard G

    2016-05-03

    Activated carbon (AC) sediment amendment for hydrophobic organic contaminants (HOCs) is attracting increasing regulatory and industrial interest. However, mechanistic and well-vetted models are needed. Here, we conduct an 18 month field mesocosm trial at a site containing dichlorodiphenyltrichloroethane (DDT) and chlordane. Different AC applications were applied and, for the first time, a recently published mass transfer model was field tested under varying experimental conditions. AC treatment was effective in reducing DDT and chlordane concentration in polyethylene (PE) samplers, and contaminant extractability by Arenicola brasiliensis digestive fluids. A substantial AC particle size effect was observed. For example, chlordane concentration in PE was reduced by 93% 6 months post-treatment in the powdered AC (PAC) mesocosm, compared with 71% in the granular AC (GAC) mesocosm. Extractability of sediment-associated DDT and chlordane by A. brasiliensis digestive fluids was reduced by at least a factor of 10 in all AC treatments. The model reproduced the relative effects of varying experimental conditions (particle size, dose, mixing time) on concentrations in polyethylene passive samplers well, in most cases within 25% of experimental observations. Although uncertainties such as the effect of long-term AC fouling by organic matter remain, the study findings support the use of the model to assess long-term implications of AC amendment.

  9. Responses of Lumbriculus variegatus to activated carbon amendments in uncontaminated sediments.

    PubMed

    Nybom, Inna; Werner, David; Leppänen, Matti T; Siavalas, George; Christanis, Kimon; Karapanagioti, Hrissi K; Kukkonen, Jussi V K; Akkanen, Jarkko

    2012-12-04

    Activated carbon (AC) amendment is a recently developed sediment remediation method. The strong hydrophobic organic contaminant sorption efficiency of AC has been shown in several studies, but effects on benthic organisms require more investigation. The AC induced effects on egestion rate, growth and reproduction of Lumbriculus variegatus were studied by applying bituminous coal based AC in three different particle size fractions, namely <63 μm (90%, AC(p)), 63-200 μm (AC(m)) and 1000 μm (AC(g)), to natural uncontaminated (HS) and artificial sediment (AS). Egestion rate, growth and reproduction decreased with increasing AC concentration and finer AC particle fractions, effects being stronger on HS than on AS sediment. Lipid content in AS was reduced already at the lowest AC doses applied (AC(p) and AC(m) 0.05%, AC(g) 0.25%). In addition, hormesis-like response was observed in growth (AS) and reproduction (AS, HS) indicating that AC may disturb organisms even at very low doses. Potential ecological effects need to be further evaluated in an amendment- and site-specific manner.

  10. 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.

  11. Current state of in situ subsurface remediation by activated carbon-based amendments.

    PubMed

    Fan, Dimin; Gilbert, Edward J; Fox, Tom

    2017-02-21

    The last decade has seen a growing interest in applying activated carbon (AC)-based amendments for in situ subsurface remediation of organic contaminants such as chlorinated solvents and petroleum hydrocarbons. This remedial technology has been promoted by several major AC-based product vendors on the market. These products involve impregnation or co-application of chemical or biological additives to facilitate various contaminant degradation processes in conjunction with contaminant adsorption. During field applications, rapid contaminant removal and limited rebound after emplacement have often been reported and considered as two major advantages for this remedial technology. Nevertheless, questions remain to be answered regarding its true effectiveness and longevity given the lack of subsequent field characterizations and evidence of the degradation process, especially biodegradation. Additional uncertainties reside in how subsurface heterogeneity may affect the design, implementation and performance monitoring of this technology. In light of these uncertainties, this review presents an independent analysis that focuses on both the scientific and practical aspects of AC-based remedial technology for in situ subsurface remediation by gathering and synthesizing the scientific knowledge and practical lessons from a broad range of contaminant removal processes involving adsorption and/or degradation. The analysis showed that the scientific soundness of combining adsorption and degradation proposed for all the AC-based products is well supported by the literature on ex situ treatment. However, the in situ effectiveness might be affected by additional factors, such as geological heterogeneity, amendment transport and distribution, and total contaminant mass, which require more thorough and quantitative evaluation. Overall, the technology may provide a viable tool in addressing major remediation challenges encountered in current practice, such as mitigation of back

  12. Modeling polychlorinated biphenyl mass transfer after amendment of contaminated sediment with activated carbon

    SciTech Connect

    David Werner; Upal Ghosh; Richard G. Luthy

    2006-07-01

    The sorption kinetics and concentration of polychlorinated biphenyls (PCBs) in historically polluted sediment is modeled to assess a remediation strategy based on in situ PCB sequestration by mixing with activated carbon (AC). The authors extend their evaluation of a model based on intraparticle diffusion by including a biomimetic semipermeable membrane device (SPMD) and a first-order degradation rate for the aqueous phase. The model predictions are compared with the previously reported experimental PCB concentrations in the bulk water phase and in SPMDs. The simulated scenarios comprise a marine and a freshwater sediment, four PCB congeners, two AC grain sizes, four doses of AC, and comparison with laboratory experiments. The modeling approach distinguishes between two different sediment particles types: a light-density fraction representing carbonaceous particles such as charcoal, coal, coke, cenospheres, or wood, and a heavy-density fraction representing the mineral phase with coatings of organic matter. A third particle type in the numerical model is AC. The model qualitatively reproduces the observed shifts in the PCB distribution during repartitioning after AC amendment but overestimates the overall effect of the treatment in reducing aqueous and SPMD concentrations of PCBs by a factor of 2-6. For the AC application in sediment, competitive sorption of the various solutes apparently requires a reduction by a factor of 16 of the literature values for the AC-water partitioning coefficient measured in pure aqueous systems. With this correction, model results and measurements agree within a factor of 3. After AC amendment is homogeneously mixed into the sediment and then left undisturbed, aqueous PCB concentrations tend toward the same reduction after 5 years. 19 refs., 5 figs., 4 tabs.

  13. Effect of Activated Carbon Amendment on Bacterial Community Structure and Functions in a PAH Impacted Urban Soil

    PubMed Central

    2012-01-01

    We collected urban soil samples impacted by polycyclic aromatic hydrocarbons (PAHs) from a sorbent-based remediation field trial to address concerns about unwanted side-effects of 2% powdered (PAC) or granular (GAC) activated carbon amendment on soil microbiology and pollutant biodegradation. After three years, total microbial cell counts and respiration rates were highest in the GAC amended soil. The predominant bacterial community structure derived from denaturing gradient gel electrophoresis (DGGE) shifted more strongly with time than in response to AC amendment. DGGE band sequencing revealed the presence of taxa with closest affiliations either to known PAH degraders, e.g. Rhodococcus jostii RHA-1, or taxa known to harbor PAH degraders, e.g. Rhodococcus erythropolis, in all soils. Quantification by real-time polymerase chain reaction yielded similar dioxygenases gene copy numbers in unamended, PAC-, or GAC-amended soil. PAH availability assessments in batch tests showed the greatest difference of 75% with and without biocide addition for unamended soil, while the lowest PAH availability overall was measured in PAC-amended, live soil. We conclude that AC had no detrimental effects on soil microbiology, AC-amended soils retained the potential to biodegrade PAHs, but the removal of available pollutants by biodegradation was most notable in unamended soil. PMID:22455603

  14. Effect of activated carbon amendment on bacterial community structure and functions in a PAH impacted urban soil.

    PubMed

    Meynet, Paola; Hale, Sarah E; Davenport, Russell J; Cornelissen, Gerard; Breedveld, Gijs D; Werner, David

    2012-05-01

    We collected urban soil samples impacted by polycyclic aromatic hydrocarbons (PAHs) from a sorbent-based remediation field trial to address concerns about unwanted side-effects of 2% powdered (PAC) or granular (GAC) activated carbon amendment on soil microbiology and pollutant biodegradation. After three years, total microbial cell counts and respiration rates were highest in the GAC amended soil. The predominant bacterial community structure derived from denaturing gradient gel electrophoresis (DGGE) shifted more strongly with time than in response to AC amendment. DGGE band sequencing revealed the presence of taxa with closest affiliations either to known PAH degraders, e.g. Rhodococcus jostii RHA-1, or taxa known to harbor PAH degraders, e.g. Rhodococcus erythropolis, in all soils. Quantification by real-time polymerase chain reaction yielded similar dioxygenases gene copy numbers in unamended, PAC-, or GAC-amended soil. PAH availability assessments in batch tests showed the greatest difference of 75% with and without biocide addition for unamended soil, while the lowest PAH availability overall was measured in PAC-amended, live soil. We conclude that AC had no detrimental effects on soil microbiology, AC-amended soils retained the potential to biodegrade PAHs, but the removal of available pollutants by biodegradation was most notable in unamended soil.

  15. Bioavailability assessments following biochar and activated carbon amendment in DDT-contaminated soil.

    PubMed

    Denyes, Mackenzie J; Rutter, Allison; Zeeb, Barbara A

    2016-02-01

    The effects of 2.8% w/w granulated activated carbon (GAC) and two types of biochar (Burt's and BlueLeaf) on DDT bioavailability in soil (39 μg/g) were investigated using invertebrates (Eisenia fetida), plants (Cucurbita pepo spp. pepo) and a polyoxymethylene (POM) passive sampler method. Biochar significantly reduced DDT accumulation in E. fetida (49%) and showed no detrimental effects to invertebrate health. In contrast, addition of GAC caused significant toxic effects (invertebrate avoidance and decreased weight) and did not significantly reduce the accumulation of DDT into invertebrate tissue. None of the carbon amendments reduced plant uptake of DDT. Bioaccumulation of 4,4'DDT and 4,4'-DDE in plants (C. pepo spp. pepo) and invertebrates (E. fetida) was assessed using bioaccumulation factors (BAFs) and compared to predicted bioavailability using the freely-dissolved porewater obtained from a polyoxymethylene (POM) equilibrium biomimetic method. The bioavailable fraction predicted by the POM samplers correlated well with measured invertebrate uptake (<50% variability), but was different from plant root uptake by 134%. A literature review of C. pepo BAFs across DDT soil contamination levels and the inclusion of field data from a 2.5 μg/g DDT-contaminated site found that these plants exhibit a concentration threshold effect at [DDT](soil) > 10 μg/g. The results of these studies illustrate the importance of including plants in bioavailability studies as the use of carbon materials for in situ contaminant sorption moves from predominantly sediment to soil remediation technologies.

  16. Effects of straw and biochar amendments on aggregate stability, soil organic carbon, and enzyme activities in the Loess Plateau, China.

    PubMed

    Zhang, Man; Cheng, Gong; Feng, Hao; Sun, Benhua; Zhao, Ying; Chen, Haixin; Chen, Jing; Dyck, Miles; Wang, Xudong; Zhang, Jianguo; Zhang, Afeng

    2017-02-23

    Soil from the Loess Plateau of China is typically low in organic carbon and generally has poor aggregate stability. Application of organic amendments to these soils could help to increase and sustain soil organic matter levels and thus to enhance soil aggregate stability. A field experiment was carried out to evaluate the effect of the application of wheat straw and wheat straw-derived biochar (pyrolyzed at 350-550 °C) amendments on soil aggregate stability, soil organic carbon (SOC), and enzyme activities in a representative Chinese Loess soil during summer maize and winter wheat growing season from 2013 to 2015. Five treatments were set up as follows: no fertilization (CK), application of inorganic fertilizer (N), wheat straw applied at 8 t ha(-1) with inorganic fertilizer (S8), and wheat straw-derived biochar applied at 8 t ha(-1) (B8) and 16 t ha(-1) (B16) with inorganic fertilizer, respectively. Compared to the N treatment, straw and straw-derived biochar amendments significantly increased SOC (by 33.7-79.6%), microbial biomass carbon (by 18.9-46.5%), and microbial biomass nitrogen (by 8.3-38.2%), while total nitrogen (TN) only increased significantly in the B16 plot (by 24.1%). The 8 t ha(-1) straw and biochar applications had no significant effects on soil aggregation, but a significant increase in soil macro-aggregates (>2 mm) (by 105.8%) was observed in the B16 treatment. The concentrations of aggregate-associated SOC increased by 40.4-105.8% in macro-aggregates (>2 mm) under straw and biochar amendments relative to the N treatment. No significant differences in invertase and alkaline phosphatase activity were detected among different treatments. However, urease activity was greater in the biochar treatment than the straw treatment, indicating that biochar amendment improved the transformation of nitrogen in the soil. The carbon pool index and carbon management index were increased with straw and biochar amendments, especially in the B16

  17. PAH-sequestration capacity of granular and powder activated carbon amendments in soil, and their effects on earthworms and plants.

    PubMed

    Jakob, Lena; Hartnik, Thomas; Henriksen, Thomas; Elmquist, Marie; Brändli, Rahel C; Hale, Sarah E; Cornelissen, Gerard

    2012-07-01

    A field lysimeter study was carried out to investigate whether the amendment of 2% powder and granular activated carbon (PAC and GAC) to a soil with moderate PAH contamination had an impact on the PAH bioaccumulation of earthworms and plants, since AC is known to be a strong sorbent for organic pollutants. Furthermore, secondary effects of AC on plants and earthworms were studied through growth and nutrient uptake, and survival and weight gain. Additionally, the effect of AC amendments on soil characteristics like pH, water holding capacity, and the water retention curve of the soil were investigated. Results show that the amendment of 2% PAC had a negative effect on plant growth while the GAC increased the growth rate of plants. PAC was toxic to earthworms, demonstrated by a significant weight loss, while the results for GAC were less clear due to ambiguous results of a field and a parallel laboratory study. Both kinds of AC significantly reduced biota to soil accumulation factors (BSAFs) of PAHs in earthworms and plants. The GAC reduced the BSAFs of earthworms by an average of 47 ± 44% and the PAC amendment reduced them by 72 ± 19%. For the investigated plants the BSAFs were reduced by 46 ± 36% and 53 ± 22% by the GAC and PAC, respectively.

  18. Carbon mineralization, microbial activity and metal dynamics in tailing ponds amended with pig slurry and marble waste.

    PubMed

    Zornoza, Raúl; Faz, Ángel; Carmona, Dora M; Acosta, Jose A; Martínez-Martínez, Silvia; de Vreng, Arno

    2013-03-01

    A field experiment was set up in Cartagena-La Unión Mining District, SE Spain, aimed at evaluating the short-term effects of pig slurry (PS) amendment alone and together with marble waste (MW) on organic matter mineralization, microbial activity and stabilization of heavy metals in two tailing ponds. These structures pose environmental risk owing to high metals contents, low organic matter and nutrients, and null vegetation. Carbon mineralization, exchangeable metals and microbiological properties were monitored during 67 d. The application of amendments led to a rapid decrease of exchangeable metals concentrations, except for Cu, with decreases up to 98%, 75% and 97% for Cd, Pb and Zn, respectively. The combined addition of MW+PS was the treatment with greater reduction in metals concentrations. The addition of PS caused a significant increase in respiration rates, although in MW+PS plots respiration was lower than in PS plots. The mineralized C from the pig slurry was low, approximately 25-30% and 4-12% for PS and MW+PS treatments, respectively. Soluble carbon (Csol), microbial biomass carbon (MBC) and β-galactosidase and β-glucosidase activities increased after the application of the organic amendment. However, after 3d these parameters started a decreasing trend reaching similar values than control from approximately day 25 for Csol and MBC. The PS treatment promoted highest values in enzyme activities, which remained high upon time. Arylesterase activity increased in the MW+PS treatment. Thus, the remediation techniques used improved soil microbiological status and reduced metal availability. The combined application of PS+MW reduced the degradability of the organic compounds.

  19. Activated carbon amendment as a treatment for residual DDT in sediment from a superfund site in San Francisco Bay, Richmond, California, USA.

    PubMed

    Tomaszewski, Jeanne E; Werner, David; Luthy, Richard G

    2007-10-01

    Pesticide formulators formerly operating at Lauritzen Channel, a portion of San Francisco Bay near Richmond (CA, USA), caused contamination of sediment with dichlorodiphenyltrichloroethane (DDT). The present study evaluated the distribution of residual DDT in channel sediment six years following extensive remedial dredging. High DDT concentrations (up to 252 mg/ kg) were found in Young Bay Mud sampled across the channel. Particle analyses showed most of the contamination is contained in the clay/silt sediment fraction, and desorption tests showed that availability is greater for DDT metabolites than parent DDT. The present study examined the feasibility of using activated carbon amendment to sequester DDT from sediment, including an evaluation of reactivated carbon as a less costly alternative to virgin activated carbons. Treatment success of activated carbon amendment to sediment collected from Lauritzen Channel was measured by reductions in aqueous equilibrium concentrations and uptake in semipermeable membrane devices (SPMDs). Four different activated carbons were tested and, after one month of treatment with 3.2 weight % carbon, DDT aqueous equilibrium concentrations were reduced up to 83% and SPMD uptake was reduced up to 91%. Reactivated carbon was comparable with virgin carbons in all tests. Reduction in SPMD uptake of DDT by treatment with 3.2% reactivated carbon increased to 99% after 26 months of treatment. The effectiveness of activated carbon was dependent on the type, size, dose, and contact time. The results show the potential usefulness of activated carbon amendment as a follow-up remedial technology for management of residuals after dredging contaminated sediment.

  20. Field application of activated carbon amendment for in-situ stabilization of polychlorinated biphenyls in marine sediment.

    PubMed

    Cho, Yeo-Myoung; Ghosh, Upal; Kennedy, Alan J; Grossman, Adam; Ray, Gary; Tomaszewski, Jeanne E; Smithenry, Dennis W; Bridges, Todd S; Luthy, Richard G

    2009-05-15

    We report results on the first field-scale application of activated carbon (AC) amendment to contaminated sediment for in-situ stabilization of polychlorinated biphenyls (PCBs). The test was performed on a tidal mud flat at South Basin, adjacent to the former Hunters Point Naval Shipyard, San Francisco Bay, CA. The major goals of the field study were to (1) assess scale up of the AC mixing technology using two available, large-scale devices, (2) validate the effectiveness of the AC amendment at the field scale, and (3) identify possible adverse effects of the remediation technology. Also, the test allowed comparison among monitoring tools, evaluation of longer-term effectiveness of AC amendment, and identification of field-related factors that confound the performance of in-situ biological assessments. Following background pretreatment measurements, we successfully incorporated AC into sediment to a nominal 30 cm depth during a single mixing event, as confirmed by total organic carbon and black carbon contents in the designated test plots. The measured AC dose averaged 2.0-3.2 wt% and varied depending on sampling locations and mixing equipment. AC amendment did not impact sediment resuspension or PCB release into the water column over the treatment plots, nor adversely impactthe existing macro benthic community composition, richness, or diversity. The PCB bioaccumulation in marine clams was reduced when exposed to sediment treated with 2% AC in comparison to the control plot Field-deployed semi permeable membrane devices and polyethylene devices showed about 50% reduction in PCB uptake in AC-treated sediment and similar reduction in estimated pore-water PCB concentration. This reduction was evident even after 13-month post-treatment with then 7 months of continuous exposure, indicating AC treatment efficacy was retained for an extended period. Aqueous equilibrium PCB concentrations and PCB desorption showed an AC-dose response. Field-exposed AC after 18 months

  1. Positioning activated carbon amendment technologies in a novel framework for sediment management.

    PubMed

    Kupryianchyk, Darya; Rakowska, Magdalena I; Reible, Danny; Harmsen, Joop; Cornelissen, Gerard; van Veggel, Marc; Hale, Sarah E; Grotenhuis, Tim; Koelmans, Albert A

    2015-04-01

    Contaminated sediments can pose serious threats to human health and the environment by acting as a source of toxic chemicals. The amendment of contaminated sediments with strong sorbents like activated C (AC) is a rapidly developing strategy to manage contaminated sediments. To date, a great deal of attention has been paid to the technical and ecological features and implications of sediment remediation with AC, although science in this field still is rapidly evolving. This article aims to provide an update on the recent literature on these features, and provides a comparison of sediment remediation with AC to other sediment management options, emphasizing their full-scale application. First, a qualitative overview of advantages of current alternatives to remediate contaminated sediments is presented. Subsequently, AC treatment technology is critically reviewed, including current understanding of the effectiveness and ecological safety for the use of AC in natural systems. Finally, this information is used to provide a novel framework for supporting decisions concerning sediment remediation and beneficial reuse.

  2. Effects of temperature on adsorption and oxidative degradation of bisphenol A in an acid-treated iron-amended granular activated carbon

    EPA Science Inventory

    The present study suggests a combined adsorption and Fenton oxidation using an acid treated Fe-amended granular activated carbon (Fe-GAC) for effective removal of bisphenol A in water. When the Fe-GAC adsorbs and is saturated with BPA in water, Fenton oxidation of BPA occurs in ...

  3. Biodynamic modeling of PCB uptake by Macoma balthica and Corbicula fluminea from sediment amended with activated carbon

    USGS Publications Warehouse

    McLeod, Pamela B.; Luoma, S.N.; Luthy, R.G.

    2008-01-01

    Activated carbon amendment was assessed in the laboratory as a remediation strategy for freshwater sediment contaminated with polychlorinated biphenyls (PCBs) from the Grasse River (near Massena, NY). Three end points were evaluated: aqueous equilibrium PCB concentration, uptake into semipermeable membrane devices (SPMDs), and 28-day bioaccumulation in the clam Corbicula fluminea. PCB uptake by water, SPMDs, and clams followed similar trends, with reductions increasing as a function of carbon dose. Average percent reductions in clam tissue PCBs were 67, 86, and 95% for activated carbon doses of 0.7, 1.3, and 2.5% dry wt, respectively. A biodynamic model that incorporates sediment geochemistry and dietary and aqueous uptake routes was found to agree well with observed uptake by C. fluminea in our laboratory test systems. Results from this study were compared to 28-day bioaccumulation experiments involving PCB-contaminated sediment from Hunters Point Naval Shipyard (San Francisco Bay, CA) and the clam Macoma balthica. Due to differences in feeding strategy, M. balthica deposit-feeds whereas C. fluminea filter-feeds, the relative importance of the aqueous uptake route is predicted to be much higher for C. fluminea than for M. balthica. Whereas M. balthica takes up approximately 90% of its body burden through sediment ingestion, C. fluminea only accumulates approximately 45% via this route. In both cases, results strongly suggest that it is the mass transfer of PCBs from native sediment to added carbon particles, not merely reductions in aqueous PCB concentrations, that effectively reduces PCB bioavailability and uptake by sediment-dwelling organisms. ?? 2008 American Chemical Society.

  4. Biodynamic modeling of PCB uptake by Macoma balthica and Corbicula fluminea from sediment amended with activated carbon.

    PubMed

    McLeod, Pamela B; Luoma, Samuel N; Luthy, Richard G

    2008-01-15

    Activated carbon amendment was assessed in the laboratory as a remediation strategy for freshwater sediment contaminated with polychlorinated biphenyls (PCBs) from the Grasse River (near Massena, NY). Three end points were evaluated: aqueous equilibrium PCB concentration, uptake into semipermeable membrane devices (SPMDs), and 28-day bioaccumulation in the clam Corbicula fluminea. PCB uptake by water, SPMDs, and clams followed similar trends, with reductions increasing as a function of carbon dose. Average percent reductions in clam tissue PCBs were 67, 86, and 95% for activated carbon doses of 0.7, 1.3, and 2.5% dry wt, respectively. A biodynamic model that incorporates sediment geochemistry and dietary and aqueous uptake routes was found to agree well with observed uptake by C. fluminea in our laboratory test systems. Results from this study were compared to 28-day bioaccumulation experiments involving PCB-contaminated sediment from Hunters Point Naval Shipyard (San Francisco Bay, CA) and the clam Macoma balthica. Due to differences in feeding strategy, M. balthica deposit-feeds whereas C. fluminea filter-feeds, the relative importance of the aqueous uptake route is predicted to be much higher for C. fluminea than for M. balthica. Whereas M. balthica takes up approximately 90% of its body burden through sediment ingestion, C. fluminea only accumulates approximately 45% via this route. In both cases, results strongly suggest that it is the mass transfer of PCBs from native sediment to added carbon particles, not merely reductions in aqueous PCB concentrations, that effectively reduces PCB bioavailability and uptake by sediment-dwelling organisms.

  5. Equilibrium and kinetic modeling of contaminant immobilization by activated carbon amended to sediments in the field.

    PubMed

    Rakowska, Magdalena I; Kupryianchyk, Darya; Koelmans, Albert A; Grotenhuis, Tim; Rijnaarts, Huub H M

    2014-12-15

    Addition of activated carbons (AC) to polluted sediments and soils is an attractive remediation technique aiming at reducing pore water concentrations of hydrophobic organic contaminants (HOCs). In this study, we present (pseudo-)equilibrium as well as kinetic parameters for sorption of a series of PAHs and PCBs to powdered and granular activated carbons (AC) after three different sediment treatments: sediment mixed with powdered AC (PAC), sediment mixed with granular AC (GAC), and addition of GAC followed by 2 d mixing and subsequent removal ('sediment stripping'). Remediation efficiency was assessed by quantifying fluxes of PAHs towards SPME passive samplers inserted in the sediment top layer, which showed that the efficiency decreased in the order of PAC > GAC stripping > GAC addition. Sorption was very strong to PAC, with Log KAC (L/kg) values up to 10.5. Log KAC values for GAC ranged from 6.3-7.1 and 4.8-6.2 for PAHs and PCBs, respectively. Log KAC values for GAC in the stripped sediment were 7.4-8.6 and 5.8-7.7 for PAH and PCB. Apparent first order adsorption rate constants for GAC (kGAC) in the stripping scenario were calculated with a first-order kinetic model and ranged from 1.6 × 10(-2) (PHE) to 1.7 × 10(-5) d(-1) (InP). Sorption affinity parameters did not change within 9 months post treatment, confirming the longer term effectiveness of AC in field applications for PAC and GAC.

  6. Modeling the mass transfer of hydrophobic organic pollutants in briefly and continuously mixed sediment after amendment with activated carbon.

    PubMed

    Hale, Sarah E; Werner, David

    2010-05-01

    Activated carbon (AC) amendment is currently being investigated as an in situ remediation technique for sediments contaminated by persistent organic pollutants. Understanding the mass transfer of pollutants from weaker binding sites on sediment particles, to stronger binding sites inside AC particles, is important for the evaluation of this strategy. Here we study the mass transfer of polycyclic aromatic hydrocarbons (PAHs) from River Tyne sediment to polyethylene (PE) passive samplers in the presence and absence of AC under two mixing regimes. Continuously mixing and a brief initial mixing period to incorporate AC to the system, followed by unmixed conditions in settled sediments, were compared. The reduction in total PAH concentration in the PE sampler was greater than 99% after 12 months AC contact for both conditions. A numerical model based on concepts used to simulate well-mixed AC-sediment slurries was further developed to describe the briefly mixed system. These models could predict upper and lower limits for the expected remediation effectiveness for variable AC-sediment mixing regimes. It appears that mixing mode has a small impact on the treatment effectiveness for River Tyne sediment which has a strongly bound, slowly released pollutant source. However, a greater impact is anticipated for contaminated sediments containing more available pollutants.

  7. Measuring and modeling reduction of DDT availability to the water column and mussels following activated carbon amendment of contaminated sediment.

    PubMed

    Tomaszewski, Jeanne E; McLeod, Pamela B; Luthy, Richard G

    2008-10-01

    A 28-day accumulation study demonstrated the use of mussel uptake, passive samplers, and biodynamic modeling to measure the reduction of dichlorodiphenyltrichloroethane (DDT) availability in the water column after the addition of activated carbon to contaminated sediment. Sediment collected from Lauritzen Channel, Richmond, California (16.5mg total DDT/kg) was mixed with either virgin activated carbon or a reactivated carbon for one month, after which a 28-day laboratory exposure study was completed. Mussels (Mytilus edulis) suspended above activated carbon-treated sediment accumulated significantly less total DDT in soft tissue, 91% and 84% for virgin and reactivated carbon, respectively, as compared to untreated sediment. Mussel tissue concentrations correlated to concentrations in semipermeable membrane devices (SPMDs) and polyethylene devices (PEDs) suspended over the same sediments. A biodynamic model that incorporated DDT water concentrations, either analytically measured or estimated from PED uptake, described mussel accumulation over time. Thus, passive samplers in combination with biodynamic modeling may provide an important screening tool for assessment of filter-feeding uptake and ecological risk to water-dwelling organisms exposed to aqueous phase hydrophobic organic contaminants.

  8. Fenton-driven regeneration of MTBE-spent granular activated carbon - Effects of particle size and Iron Amendment Procedures

    EPA Science Inventory

    Fenton-driven regeneration of spent granular activated carbon (GAC) is a technology being developed to regenerate organic contaminant-spent GAC. Here, the effect of GAC particle size (>2 mm to <0.35 mm) on Fenton-driven oxidation of methyl tert-butyl ether (MTBE)-spent GAC was ev...

  9. Long-term monitoring and modeling of the mass transfer of polychlorinated biphenyls in sediment following pilot-scale in-situ amendment with activated carbon

    NASA Astrophysics Data System (ADS)

    Cho, Yeo-Myoung; Werner, David; Choi, YongJu; Luthy, Richard G.

    2012-03-01

    The results of five years of post-treatment monitoring following in-situ activated carbon (AC) placement for stabilization of polychlorinated biphenyls (PCBs) at an inter-tidal mudflat adjacent to Hunters Point Shipyard, San Francisco Bay, CA, USA are reported in this paper. After five years, AC levels of the sediment cores were comparable to those at earlier sampling times. Passive sampler uptake validated the benefit of the AC amendment with a strong local sorbent dose-response relationship. The PCB uptakes in passive samplers decreased up to 73% with a 3.7 dry wt.% AC dose after five years, confirming the temporal enhancement of the amendment benefit from a 19% reduction with a 4.4% dose observed within one month. The long-term effectiveness of AC, the local AC dose response, the impact of fouling by NOM, the spatial heterogeneity of AC incorporation, and the effects of advective sediment pore-water movement are discussed with the aid of a PCB mass transfer model. Modeling and experimental results indicated that the homogeneous incorporation of AC in the sediment will significantly accelerate the benefit of the treatment.

  10. Long-term monitoring and modeling of the mass transfer of polychlorinated biphenyls in sediment following pilot-scale in-situ amendment with activated carbon.

    PubMed

    Cho, Yeo-Myoung; Werner, David; Choi, Yongju; Luthy, Richard G

    2012-03-15

    The results of five years of post-treatment monitoring following in-situ activated carbon (AC) placement for stabilization of polychlorinated biphenyls (PCBs) at an inter-tidal mudflat adjacent to Hunters Point Shipyard, San Francisco Bay, CA, USA are reported in this paper. After five years, AC levels of the sediment cores were comparable to those at earlier sampling times. Passive sampler uptake validated the benefit of the AC amendment with a strong local sorbent dose-response relationship. The PCB uptakes in passive samplers decreased up to 73% with a 3.7 dry wt.% AC dose after five years, confirming the temporal enhancement of the amendment benefit from a 19% reduction with a 4.4% dose observed within one month. The long-term effectiveness of AC, the local AC dose response, the impact of fouling by NOM, the spatial heterogeneity of AC incorporation, and the effects of advective sediment pore-water movement are discussed with the aid of a PCB mass transfer model. Modeling and experimental results indicated that the homogeneous incorporation of AC in the sediment will significantly accelerate the benefit of the treatment.

  11. Carbon and nitrogen mineralization in vineyard acid soils amended with a bentonitic winery waste

    NASA Astrophysics Data System (ADS)

    Fernández-Calviño, David; Rodríguez-Salgado, Isabel; Pérez-Rodríguez, Paula; Díaz-Raviña, Montserrat; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

    2015-04-01

    Carbon mineralization and nitrogen ammonification processes were determined in different vineyard soils. The measurements were performed in samples non-amended and amended with different bentonitic winery waste concentrations. Carbon mineralization was measured as CO2 released by the soil under laboratory conditions, whereas NH4+ was determined after its extraction with KCl 2M. The time evolution of both, carbon mineralization and nitrogen ammonification, was followed during 42 days. The released CO2 was low in the analyzed vineyard soils, and hence the metabolic activity in these soils was low. The addition of the bentonitic winery waste to the studied soils increased highly the carbon mineralization (2-5 fold), showing that the organic matter added together the bentonitic waste to the soil have low stability. In both cases, amended and non-amended samples, the maximum carbon mineralization was measured during the first days (2-4 days), decreasing as the incubation time increased. The NH4+ results showed an important effect of bentonitic winery waste on the ammonification behavior in the studied soils. In the non-amended samples the ammonification was no detected in none of the soils, whereas in the amended soils important NH4+ concentrations were detected. In these cases, the ammonification was fast, reaching the maximum values of NH4 between 7 and 14 days after the bentonitic waste additions. Also, the percentages of ammonification respect to the total nitrogen in the soil were high, showing that the nitrogen provided by the bentonitic waste to the soil is non-stable. The fast carbon mineralization found in the soils amended with bentonitic winery wastes shows low possibilities of the use of this waste for the increasing the organic carbon pools in the soil.On the other hand, the use of this waste as N-fertilizer can be possible. However, due its fast ammonification, the waste should be added to the soils during active plant growth periods.

  12. Potential for Carbon Sequestration using Organic Amendments on Rangeland Soils

    NASA Astrophysics Data System (ADS)

    Ryals, R.; Silver, W. L.

    2009-12-01

    Managed rangelands represent a geographically large land-use footprint and thus have considerable potential to sequester carbon (C) in soil through changes in management practices. Organic amendments are frequently added to agricultural and rangeland soils in an effort to improve fertility and yield, yet little is known about their impact on greenhouse gas dynamics and soil biogeochemical dynamics, especially in rangeland soils. This research aims to explore the effects of organic amendments on soil chemical and physical properties, plant inputs, and soil C and N dynamics in managed rangeland ecosystems. Our research uses field manipulations at two Mediterranean grassland ecosystems replicated within and across bioclimatic zones: the Sierra Foothills Research and Extension Center (SFREC) in Browns Valley, CA and the Nicasio Native Grass Ranch in Nicasio, CA. Both sites are dominated by annual grasses and are moderately grazed by cattle. Three replicate blocks at each site contain 60m x 25m treatment plots (organic amendments and control) with 5m buffer strips. Organic amendments were applied at a level of 14 MgC/ha (equivalent to a 1.27cm surface dressing) at the beginning of the wet season (December 2008). During the wet season (October through June), carbon dioxide (CO2) flux was measured weekly using a LI-8100, while fluxes of methane (CH4) and nitrous oxide (N2O) were measured biweekly using static flux chambers. During the dry season (June through September), fluxes were measured biweekly and monthly, respectively. Soil organic C (SOC) and nitrogen (N) were measured prior to treatment and seven months following treatment at 0-10, 10-30, 30-50, and 50-100 cm depths. Soil moisture and temperature were measured continuously. Changes in oxidative and hydrolytic extracellular enzyme activities are also being explored. After the first year of management, both sites responded similarly to treatments in both trend and magnitude. For example, at SFREC, total soil

  13. Effect of phosphogypsum amendment on soil physico-chemical properties, microbial load and enzyme activities.

    PubMed

    Nayak, Soumya; Mishra, C S K; Guru, B C; Rath, Monalisa

    2011-09-01

    Phosphogypsum (PG) is produced as a solid waste from phosphatic fertilizer plants. The waste slurry is disposed off in settling ponds or in heaps. This solid waste is now increasingly being used as a calcium supplement in agriculture. This study reports the effectof PG amendmenton soil physico chemical properties, bacterial and fungal count and activities of soil enzymes such as invertase, cellulase and amylase over an incubation period of 28 days. The highest mean percent carbon loss (55.98%) was recorded in 15% PG amended soil followed by (55.28%) in 10% PG amended soil and the minimum (1.68%) in control soil. The highest number of bacterial colonies (47.4 CFU g(-1) soil), fungal count (17.8 CFU g(-1) soil), highest amylase activity (38.4 microg g(-1) soil hr(-1)) and cellulase activity (38.37 microg g(-1) soil hr(-1)) were recorded in 10% amended soil. Statistically significant difference (p<0.05) has been recorded in the activities of amylase and cellulase over the period of incubation irrespective of amendments. Considering the bacterial and fungal growth and the activities of the three soil enzymes in the control and amended sets, it appears that 10% PG amendment is optimal for microbial growth and soil enzyme activities.

  14. 10 CFR 63.46 - Particular activities requiring license amendment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Particular activities requiring license amendment. 63.46 Section 63.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Licenses License Issuance and Amendment §...

  15. 10 CFR 63.46 - Particular activities requiring license amendment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Particular activities requiring license amendment. 63.46 Section 63.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Licenses License Issuance and Amendment §...

  16. 10 CFR 63.46 - Particular activities requiring license amendment.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Particular activities requiring license amendment. 63.46 Section 63.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Licenses License Issuance and Amendment §...

  17. 10 CFR 63.46 - Particular activities requiring license amendment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false Particular activities requiring license amendment. 63.46 Section 63.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Licenses License Issuance and Amendment §...

  18. 10 CFR 63.46 - Particular activities requiring license amendment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Particular activities requiring license amendment. 63.46 Section 63.46 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Licenses License Issuance and Amendment §...

  19. Application of calcium carbonate slows down organic amendments mineralization in reclaimed soils

    NASA Astrophysics Data System (ADS)

    Zornoza, Raúl; Faz, Ángel; Acosta, José A.; Martínez-Martínez, Silvia; Ángeles Muñoz, M.

    2014-05-01

    A field experiment was set up in Cartagena-La Unión Mining District, SE Spain, aimed at evaluating the short-term effects of pig slurry (PS) amendment alone and together with marble waste (MW) on organic matter mineralization, microbial activity and stabilization of heavy metals in two tailing ponds. These structures pose environmental risk owing to high metals contents, low organic matter and nutrients, and null vegetation. Carbon mineralization, exchangeable metals and microbiological properties were monitored during 67 days. The application of amendments led to a rapid decrease of exchangeable metals concentrations, except for Cu, with decreases up to 98%, 75% and 97% for Cd, Pb and Zn, respectively. The combined addition of MW+PS was the treatment with greater reduction in metals concentrations. The addition of PS caused a significant increase in respiration rates, although in MW+PS plots respiration was lower than in PS plots. The mineralised C from the pig slurry was low, approximately 25-30% and 4-12% for PS and MW+PS treatments, respectively. Soluble carbon (Csol), microbial biomass carbon (MBC) and β-galactosidase and β-glucosidase activities increased after the application of the organic amendment. However, after 3 days these parameters started a decreasing trend reaching similar values than control from approximately day 25 for Csol and MBC. The PS treatment promoted highest values in enzyme activities, which remained high upon time. Arylesterase activity increased in the MW+PS treatment. Thus, the remediation techniques used improved soil microbiological status and reduced metal availability. The combined application of PS+MW reduced the degradability of the organic compounds. Keywords: organic wastes, mine soils stabilization, carbon mineralization, microbial activity.

  20. Amendments and mulches improve the biological quality of soils degraded by mining activities in SE Spain

    NASA Astrophysics Data System (ADS)

    Luna Ramos, Lourdes; Miralles Mellado, Isabel; Hernández Fernández, María Teresa; García Izquierdo, Carlos; Solé Benet, Albert

    2014-05-01

    Mining and quarrying activities generate negative visual impacts in the landscape and a loss of environmental quality. Substrate properties at the end of mining are in general not suitable for plant growth, even native ones. In an experimental soil restoration in limestone quarries from Sierra de Gádor (Almería), SE Spain, the effect of organic amendment (sewage sludge, compost from the organic fraction of domestic waste or non-amendment) combined or not with two different kind of mulches (fine gravel, chopped forest residue) was tested by triplicate in 5 x 5 m plots with the aim to improve soil/substrate properties and to reduce evaporation and erosion. In each experimental plot 75 native plants (Stipa tenacissima, Anthyllis terniflora and Anthyllis cytisoides) were planted. Effects of adding organic amendments and mulches on some soil microbiological and biochemical parameters (microbial biomass carbon, basal respiration and different enzymatic activities, such as dehydrogenase, phosphatase, β-glucosidase and urease) were analyzed 5 years after the start of the experiment. Vegetation growth was also monitored. The two-way ANOVA, using as factors amendment and mulch, showed a significant positive influence of organic amendments on microbial biomass (Cmic), basal respiration and some enzymatic activities related to the cycles of C and N. The highest values of these parameters were obtained with compost. The influence of the mulch factor and its interactions with the amendment factor on the measured variables did not follow a clear trend with respect the measured parameters. Mulching did not improved significantly (p<0.05) the positive effect of organic amendments on Cmic although Cmic values increased with the incorporation of "forest chopped residue" and decreased with gravel incorporation. In general, both type of mulch decreased or have no effect on the microbial activity detected in the amended soils, with the only exception of the forest chopped residue

  1. Carbon dynamics in an almond orchard soil amended with raw and treated pig slurry

    NASA Astrophysics Data System (ADS)

    Domínguez, Sara G.; Zornoza, Raúl; Faz, Ángel

    2010-05-01

    In SE Spain, intensive farming is very common which supposes the generation of great amounts of pig slurries. These residues cause many storage problems due to their pollution capacity. A good management of them is necessary to avoid damages to the environment. The use of this effluent as fertilizer is a usual practice that in the correct dose is a good amend and important for sustainable development, but in excess can be a risk of polluting and damaging soil, water and crop conditions. Pig slurry is a source of many nutrients and specially rich in organic matter. The main objective of this study is to determine changes in soil organic carbon dynamics resulting from raw and treated slurry amendments applied in different doses. The experimental area is an almond orchard located in Cartagena (SE Spain). The climate of the area is semiarid Mediterranean with mean annual temperature of 18°C and mean annual rainfall of 275 mm. A total of 10 plots (12 m x 30 m) were designed, one of them being the control without fertilizer. Surface soil samples (0-25 cm) were collected in September 2009. Three different treatments were applied, raw slurry, the effluent obtained after solid-liquid separation and solid manure, all of them in three doses being the first one of 170 kg N/ha, (maximum permitted in nitrates directive 91/676/CEE), and the others two and three times the first one. Soil biochemical parameters are rapid indicators of changes in soil quality. According to this, total organic carbon, soil microbial biomass carbon, soluble carbon, and β-glucosidase, β-galactosidase and arylesterase activities were measured in order to assess some soil biochemical conditions and carbon dynamics in terms of the different treatments. As we expected, the use of these organic fertilizers rich in organic matter, had an effect on soil carbon and soil microbial activity resulting in an increase in most of the parameters; total organic carbon and β-galactosidase activity showed the

  2. Organic amendments' dissolved organic carbon influences bioavailability of agricultural soil DOC

    NASA Astrophysics Data System (ADS)

    Straathof, Angela L.; Chincarini, Riccardo; Hoffland, Ellis; Comans, Rob N. J.

    2013-04-01

    Agricultural soils benefit from additions of organic amendments because they improve soil structure, are a source of plant nutrients, and increase concentrations of soil organic carbon (SOC). The latter fuels microbial processes important for plant growth, including nutrient mineralization and the suppression of plant diseases. However, these amendment additions range in quality and quantity of C and little is known about how their properties interact with native soil C and affect turnover. The dissolved pool of SOC (DOC) may be the most important C source for these processes as it is more biologically available and thus relatively easily turned over by the soil microbial biomass. Using a rapid-batch DOC fractionation procedure, we studied the composition of different organic amendments' DOC pools and measured how their additions change the quantity and turnover of soil DOC. Fractions isolated and quantified with this procedure include humic and fulvic acids, hydrophobic neutral and hydrophilic compounds. We hypothesized that these range from biologically recalcitrant to readily available, respectively. Amendments analysed included composts of different source materials and maturation stages collected from two different compost facilities in the Netherlands. Both total DOC concentrations and proportions of the aforementioned fractions ranged highly between composts. Composts cured for >10 days had a lower proportion of hydrophilic C compounds, suggesting that these are the most bioavailable and released as CO2 via microbial activity during maturation. To measure the effects of compost DOC on soil DOC, we extracted the former and added it to a sandy soil in an incubation experiment. The amendment increased soil total DOC, CO2 production from the soil, and the pools of humic and fulvic acids as a proportion of total DOC. Turnover of C from the incubated soil was measured by substrate-induced CO2 production (an indicator of microbial activity) from a 96-well

  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. Denitrification and availability of carbon and nitrogen in a well-drained pasture soil amended with particulate organic carbon.

    PubMed

    Stevenson, Bryan A; Schipper, Louis A; McGill, Alexandra; Clark, Dave

    2011-01-01

    A well-drained soil in N-fertilized dairy pasture was amended with particulate organic carbon (POC), either sawdust or coarse woody mulch, and sampled every 4 wk for a year to test the hypothesis that the addition of POC would increase denitrification activity by increasing the number of microsites where denitrification occurred. Overall mean denitrifying enzyme activity (DEA), on a gravimetric basis, was 100% greater for the woody mulch treatment and 50% greater for the sawdust treatment compared with controls, indicating the denitrifying potential of the soil was enhanced. Despite differences in DEA, no difference in denitrification rate, as measured by the acetylene block technique, was detected among treatments, with an average annual N loss of ∼22 kg N ha yr Soil water content overall was driving denitrification in this well-drained soil as regression of the natural log of volumetric soil water content (VWC) against denitrification rate was highly significant ( = 0.74, < 0.001). Addition of the amendments, however, had significant effects on the availability of both C and N. An additional 20 to 40 kg N ha was stored in POC-amended treatments as a result of increases in the microbial biomass. Basal respiration, as a measure of available C, was 400% greater than controls in the sawdust treatment and 250% greater than controls in the mulch. Net N mineralization, however, was significantly lower in the sawdust treatment, resulting in significantly lower nitrate N levels than in the control. We attribute the lack of measured response in denitrification rate to the high temporal variability in denitrification and suggest that diffusion of nitrate may ultimately have limited denitrification in the amended treatments. Our data indicate that manipulation of denitrification by addition of POC may be possible, particularly when nitrate levels are high, but quantifying differences in the rate of denitrification is difficult because of the temporal nature of the process

  5. Development of models for predicting carbon mineralization and associated phytotoxicity in compost-amended soil.

    PubMed

    Aslam, Danielle N; Vandergheynst, Jean S; Rumsey, Thomas R

    2008-12-01

    Phytotoxicity of compost-amended soil is related to carbon mineralization associated with compost decomposition. The objective of this research was to determine if compost carbon mineralization potential, estimated using compost respiration rate measurements, could be combined with carbon mineralization kinetic models to predict phytotoxicity of compost-amended soil. First-order, second-order, and Monod kinetic models that include compost carbon mineralization potential, compost amendment rate, incubation time, and temperature were developed and compared for their ability to predict carbon mineralization kinetics. Experiments utilized two soil types amended with 0%, 5%, and 50% (v/v) food waste and green waste composts, incubated at 20 degrees C, 25 degrees C, 30 degrees C, 35 degrees C, and 45 degrees C for model development and under a diurnal temperature cycle from 20 degrees C to 30 degrees C for model validation. For most cases, a first-order model had an equivalent or better fit to the data than the other models. Mineralizable carbon estimated using the first-order model was significantly correlated to the probability of phytotoxicity in compost-amended soil.

  6. 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.

  7. Effects of Biochar Amendment on Soil Properties and Soil Carbon Sequestration

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Zhu, S.

    2015-12-01

    Biochar addition to soils potentially affects various soil properties and soil carbon sequestration, and these effects are dependent on biochars derived from different feedstock materials and pyrolysis processes. The objective of this study was to investigate the effects of amendment of different biochars on soil physical and biological properties as well as soil carbon sequestration. Biochars were produced with dairy manure and woodchip at temperatures of 300, 500, and 700°C, respectively. Each biochar was mixed at 5% (w/w) with a forest soil and the mixture was incubated for 180 days, during which soil physical and biological properties, and soil respiration rates were measured. Results showed that the biochar addition significantly enhanced the formation of soil macroaggregates at the early incubation time. The biochar application significantly reduced soil bulk density, increased the amount of soil organic matter, and stimulated microbial activity and soil respiration rates at the early incubation stage. Biochar applications improved water retention capacity, with stronger effects by biochars produced at higher pyrolysis temperatures. At the same suction, the soil with woodchip biochars possessed higher water content than with the dairy manure biochars. Biochar addition significantly affected the soil physical and biological properties, which resulted in different soil carbon mineralization rates and the amount of soil carbon storage.

  8. Carbon dioxide emission in relation with irrigation and organic amendments from a sweet corn field.

    PubMed

    Fares, Ali; Bensley, Adam; Bayabil, Haimanote; Awal, Ripendra; Fares, Samira; Valenzuela, Hector; Abbas, Farhat

    2017-03-03

    Soil moisture and organic matter level affects soil respiration and microbial activities, which in turn impact greenhouse gas (GHG) emissions. This study was conducted to evaluate the effect of irrigation levels (75% [deficit], 100% [full], and 125% [excess] of reference crop evapotranspiration requirements), and organic amendments (OA) type (chicken manure [CM] and bone meal [BM]) and OA application rates (0,168, 336 and 672 kg total N ha(-1)) on (i) soil physical properties (bulk density, organic matter content and soil moisture content) and (ii) soil carbon dioxide (CO2) emissions from a highly weathered tropical Hawai'ian soil. Carbon dioxide readings were consistently taken once or twice a week for the duration of the cropping season. A drip irrigation system was used to apply the appropriate amount of irrigation water to the treatment plots. Treatments were randomly selected and corresponding organic amendments were manually incorporated into the soil. Plots were cultivated with sweet corn (Zea mays 'SS-16'). Soil moisture content within and below the rootzone was monitored using a TDR 300 soil moisture sensor (Spectrum Technologies, Inc., Plainfield, IL, USA) connected with 12 cm long prongs. Soil bulk density and organic matter content were determined at the end of the cropping season. Analysis of variance results revealed that OA type, rate, and their interaction had significant effect on soil CO2 flux (P < 0.05). Among the OA rates, all CM mostly resulted in significantly higher soil CO2 fluxes compared to BM and control treatment (p < 0.05). The two highest rates of BM treatment were not significantly different from the control with regard to soil CO2 flux. In addition, organic amendments affected soil moisture dynamics during the crop growing season and organic matter content measured after the crop harvest. While additional studies are needed to further investigate the effect of irrigation levels on soil CO2 flux, it is recommended that in order to

  9. Can resource-use traits predict native vs. exotic plant success in carbon amended soils?

    PubMed

    Steers, Robert J; Funk, Jennifer L; Allen, Edith B

    2011-06-01

    Productivity in desert ecosystems is primarily limited by water followed by nitrogen availability. In the deserts of southern California, nitrogen additions have increased invasive annual plant abundance. Similar findings from other ecosystems have led to a general acceptance that invasive plants, especially annual grasses, are nitrophilous. Consequently, reductions of soil nitrogen via carbon amendments have been conducted by many researchers in a variety of ecosystems in order to disproportionately lower invasive species abundance, but with mixed success. Recent studies suggest that resource-use traits may predict the efficacy of such resource manipulations; however, this theory remains largely untested. We report findings from a carbon amendment experiment that utilized two levels of sucrose additions that were aimed at achieving soil carbon to nitrogen ratios of 50:1 and 100:1 in labile sources. Carbon amendments were applied once each year, for three years, corresponding with the first large precipitation event of each wet season. Plant functional traits measured on the three invasive and 11 native herbaceous species that were most common at the study site showed that exotic and native species did not differ in traits associated with nitrogen use. In fact, plant abundance measures such as density, cover, and biomass showed that carbon amendments were capable of decreasing both native and invasive species. We found that early-germinating species were the most impacted by decreased soil nitrogen resulting from amendments. Because invasive annuals typically germinate earlier and exhibit a rapid phenology compared to most natives, these species are expected to be more competitive than native annuals yet more susceptible to early-season carbon amendments. However, desert annual communities can exhibit high interannual variability in species composition and abundance. Therefore, the relative abundance of native and invasive species at the time of application is

  10. 78 FR 286 - Circular Welded Carbon Steel Pipes and Tubes From Turkey; Amended Final Results of Antidumping...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-03

    ... Welded Carbon Steel Pipes and Tubes From Turkey; Amended Final Results of Antidumping Duty Administrative... and tubes from Turkey for the period of review (POR) May 1, 2010, through April 30, 2011.\\1\\ We are..., as amended (the Act). \\1\\ See Circular Welded Carbon Steel Pipes and Tubes from Turkey; Final...

  11. Interactions between properties of amended strip mine spoils and microbial activities

    SciTech Connect

    Utsalo, S.J.

    1981-01-01

    Properties of strip mine spoils before and after amendment with varying levels of carbon and nitrogen sources are characterized and compared with properties of similarly amended garden soil samples. Changes in spoils as reflected in the stimulation of microbial populations, rate of nitrate formation, the turnover of microbial biomass and the growth yields of white clover and rye grass are evaluated. Limed spoils and garden soils were fertilized and incubated at 25/sup 0/C following amendments with organic substrates. Changes in parameters related to soil fertility status were analyzed on a weekly basis. The possible identity and the toxic effects on white clover and a Rhizobium of acidity factors present in strip mine spoils were evaluated using soil experiments and pure culture studies in artificial culture media. The results indicate that acid spoils contain low numbers of viable microorganisms which readily respond to soil amendment with substrates. No nitrification occurs in acid spoils but liming and inoculation with compost infusion stimulate active nitrification. Aluminum, manganese and acidity appear to be important factors which inhibit the survival of plants and microbes in spoils. Adequate liming improves rhizobial survival and growth and nodulation of white clover in spoils. Acidity factors have greater impact on Rhizobium than on the white clover host under nutritionally independent conditions. Increase in inoculum size enhances nodulation and growth of clover at low aluminum levels. Reducing the time of exposure of rhizobia to acidity factors outside the symbiotic host does not appear to enhance the growth yield of clover under symbiotic conditions. Molds appear to contribute more to the increased aggregate stability observed in amended soils than bacteria and actinomycetes.

  12. 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.

  13. Factors driving carbon mineralization priming effect in a soil amended with different types of biochar

    NASA Astrophysics Data System (ADS)

    Cely, P.; Tarquis, A. M.; Paz-Ferreiro, J.; Méndez, A.; Gascó, G.

    2014-03-01

    The effect of biochar on soil carbon mineralization priming effect depends on the characteristics of the raw materials, production method and pyrolysis conditions. The goal of the present study is to evaluate the impact of three different types of biochar on soil CO2 emissions and in different physicochemical properties. For this purpose, a sandy-loam soil was amended with the three biochars (BI, BII and BIII) at a rate of 8 wt % and soil CO2 emissions were measured for 45 days. BI is produced from a mixed wood sieving's from wood chip production, BII from a mixture of paper sludge and wheat husks and BIII from sewage sludge. Cumulative CO2 emissions of biochars, soil and amended soil were well fit to a simple first-order kinetic model with correlation coefficients (r2) greater than 0.97. Results shown a negative priming effect in the soil after addition of BI and a positive priming effect in the case of soil amended with BII and BIII. These results can be related with different biochar properties such as ash content, volatile matter, fixed carbon, organic carbon oxidised with dichromate, soluble carbon and metal and phenolic substances content in addition to surface biochar properties. Three biochars increased the values of soil field capacity and wilting point, while effects over pH and cation exchange capacity were not observed.

  14. 76 FR 27987 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Amended Final Results of Antidumping...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-13

    ... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes From Thailand: Amended Final... on circular welded carbon steel pipes and tubes from Thailand, which covered Saha Thai Steel Pipe... Welded Carbon Steel Pipes and Tubes from Thailand: Final Results of Antidumping Duty...

  15. 76 FR 65497 - Certain Hot-Rolled Carbon Steel Flat Products From India: Amended Final Results of Countervailing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-21

    ... International Trade Administration Certain Hot-Rolled Carbon Steel Flat Products From India: Amended Final... of the countervailing duty order on certain hot-rolled carbon steel flat products (HRCS) from India..., to reflect the CIT's decision in Essar. See Certain Hot-Rolled Carbon Steel Flat Products from...

  16. Carbon and nitrogen mineralization rates after application of organic amendments to soil.

    PubMed

    Flavel, Tamara C; Murphy, Daniel V

    2006-01-01

    The objective of this study was to quantify C and N mineralization rates from a range of organic amendments that differed in their total C and N contents and C quality, to gain a better understanding of their influence on the soil N cycle. A pelletized poultry manure (PP), two green waste-based composts (GWCa, GWCb), a straw-based compost (SBC), and a vermi-cast (VER) were incubated in a coarse-textured soil at 15 degrees C for 142 d. The C quality of each amendment was determined by chemical analysis and by 13C nuclear magnetic resonance (NMR). Carbon dioxide (CO2-C) evolution was determined using alkali traps. Gross N mineralization rates were calculated by 15N isotopic pool dilution. The CO2-C evolution rates and gross N mineralization rates were generally higher in amended soils than in the control soil. With the exception of GWCb all amendments released inorganic N at concentrations that would be high enough to warrant a reduction in inorganic N fertilizer application rates. The amount of N released from PP was high indicating that application rates should be reduced, or alternative amendments used, to minimize leaching losses in regions where ground water quality is of concern. There was a highly significant relationship between CO2-C evolution and gross N mineralization (R2= 0.95). Some of the chemically determined C quality parameters had significant relationships (p < 0.05) with both the cumulative amounts of C and N evolved. However, we found no significant relationships between 13C NMR spectral groupings, or their ratios, and either the CO2-C evolved or gross N mineralized from the amendments.

  17. 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.

  18. Temperature and moisture responses to carbon mineralization in the biochar-amended saline soil.

    PubMed

    Sun, Junna; He, Fuhong; Zhang, Zhenhua; Shao, Hongbo; Xu, Gang

    2016-11-01

    This study assessed the effects of temperature and moisture on carbon mineralization (Cmin) in a saline soil system with biochar amendment. The dynamics of Cmin were monitored in a biochar-amended saline soil for 220days by incubation experiments under different conditions of temperature (15°C, 25°C and 35°C) and moisture (30%, 70% and 105% of the water-holding capacity). Results showed that as the incubation temperature rose, cumulative Cmin consistently increased in soil added with 0-4% biochar. The two-compartment model could well describe the dynamics of Cmin. The temperature rise increased the concentration of labile C in soil, but reduced the turnover time of labile and recalcitrant C pools and the value of temperature coefficient Q10. The response of Cmin to moisture was varying in soil amended with different levels of biochar. In the control treatment (soil alone), cumulative Cmin increased only when soil moisture was >105%. In the biochar treatments, however, 70% of water-holding capacity was optimal for Cmin, except for 2%-biochar treatment at 35°C. The findings highlight the necessity to consider the combined effects of soil moisture, temperature and the amount of biochar added for assessing Cmin in biochar-amended saline soils.

  19. Microbial Community Response to Carbon Substrate Amendment in Mercury Impacted Sediments: Implications on Microbial Methylation of Mercury.

    NASA Astrophysics Data System (ADS)

    Elias, D. A.; Somenahally, A. C.; Moberly, J. G.; Hurt, R. A., Jr.; Brown, S. D.; Podar, M.; Palumbo, A. V.; Gilmour, C. C.

    2015-12-01

    Methylmercury (MeHg) is a neurotoxic and bio-accumulative product of the microbial methylation of inorganic mercury (Hg(II)). Methylating organisms are now known to exist in almost all anaerobic niches including fermentation, Fe(III)- and sulfate- reduction as well as methanogenesis. The study objective was to determine the effect of different carbon sources on the microbial community and methylating populations in particular along a Hg contaminated creek. Sediment cores from upstream and downstream at the Hg contaminated East Fork Poplar Creek (EFPC), Oak Ridge TN, and a background site were sectioned by depth, and Hg-methylation potential (HgMP) assays were performed using stable isotope spikes. Sediments from the lowest depth possessed the highest in-situ activity. Replicate samples were amended with different carbon substrates (cellulose, acetate, propionate, lactate, ethanol and methanol), spiked with stable isotopes for HgMP assays and incubated for 24hrs. Sequencing of the 16S rRNA gene was performed to determine alterations in Bacterial and Archaeal population dynamics. Additionally, bioinformatics and our new qualitative and quantitative hgcAB primers were utilized to determine microbial community structure alterations and correlate organism and gene abundance with altered MeHg generation. HgMP was significantly reduced in cellulose amended sediments while acetate and propionate slightly decreased HgMP in both sites. Methanol, ethanol and lactate increased the HgMP in EFPC downstream while cellulose amendment significantly decreased the Proteobacteria, and the Firmicutes increased but none are currently known to produce MeHg. Geobacter bemidjiensis in particular significantly decreased in cellulose amended sediments in all three sites from being predominant in-situ. This suggests that in EFPC downstream and background sites, the prevalent Hg-methyaltors might be Deltaprotebacteria, since upstream, cellulose amendment did not reduce HgMP even though

  20. Carbon dynamics in different soil types amended with pig slurry, pig manure and its biochar

    NASA Astrophysics Data System (ADS)

    Yanardag, Ibrahim H.; Zornoza, Raúl; Faz, Ángel; Büyükkiliç-Yanardaǧ, Asuman; Mermut, Ahmet R.

    2014-05-01

    Determining the structure and components of soil and soil organic matter is very important in terms of sustainable agriculture and forestry and greenhouse gases emissions. Organic management can increase labile C and N in the short-term, and total soil C and N in the long-term, but less is known about how management practices may affect soil organic C (SOC)quality and stability. Methods to improve the management of livestock slurries to reduce the environmental impact and carbon losses are gaining importance. There is a need to find the best wastes treatment which enhances soil fertility but also carbon sequestration, to mitigate the effects of global warming. The objective of this study was to assess the short-term changes in SOC pools, using raw pig slurry, the solid phase of pig slurry, and its biochar as amendment in different soil types (Regosol, Luvisol and Kastanozem). The three different amendments were applied at 5 g C kg-1 soil. An unamended soil for each type was used as control. Soils were incubated in triplicate for 60 days at 25ºC and at 55% of their water holding capacity. Samples were sampled to monitor the evolution of soil organic and inorganic carbon, recalcitrant carbon, soluble carbon, carbon mineralization, SOC thermal distribution (thermogravimetric analysis - differential scanning calorimetry - quadrupole mass spectrometry), and characterization of functional groups (Fourier transform infrared spectroscopy (FTIR)). Results showed that soils amended with raw pig slurry and the solid phase of the slurry showed higher values of soluble carbon, and higher carbon mineralization rates compared to biochar application, which showed values similar to controls. SOC increased at the end of incubation with biochar and the solid phase of the slurry applications in Kastanozem and Regosol. Thermogravimetric results showed an increased weight loss of the Regosol compared to Luvisol and Kastanozem, owing to the higher content of soil carbonates. Luvisol and

  1. Carbon amendment and soil depth affect the distribution and abundance of denitrifiers in agricultural soils.

    PubMed

    Barrett, M; Khalil, M I; Jahangir, M M R; Lee, C; Cardenas, L M; Collins, G; Richards, K G; O'Flaherty, V

    2016-04-01

    The nitrite reductase (nirS and nirK) and nitrous oxide reductase-encoding (nosZ) genes of denitrifying populations present in an agricultural grassland soil were quantified using real-time polymerase chain reaction (PCR) assays. Samples from three separate pedological depths at the chosen site were investigated: horizon A (0-10 cm), horizon B (45-55 cm), and horizon C (120-130 cm). The effect of carbon addition (treatment 1, control; treatment 2, glucose-C; treatment 3, dissolved organic carbon (DOC)) on denitrifier gene abundance and N2O and N2 fluxes was determined. In general, denitrifier abundance correlated well with flux measurements; nirS was positively correlated with N2O, and nosZ was positively correlated with N2 (P < 0.03). Denitrifier gene copy concentrations per gram of soil (GCC) varied in response to carbon type amendment (P < 0.01). Denitrifier GCCs were high (ca. 10(7)) and the bac:nirK, bac:nirS, bac:nir (T) , and bac:nosZ ratios were low (ca. 10(-1)/10) in horizon A in all three respective treatments. Glucose-C amendment favored partial denitrification, resulting in higher nir abundance and higher N2O fluxes compared to the control. DOC amendment, by contrast, resulted in relatively higher nosZ abundance and N2 emissions, thus favoring complete denitrification. We also noted soil depth directly affected bacterial, archaeal, and denitrifier abundance, possibly due to changes in soil carbon availability with depth.

  2. Carbon dioxide emissions from agricultural soils amended with livestock-derived organic materials

    NASA Astrophysics Data System (ADS)

    Pezzolla, D.; Said-Pullicino, D.; Gigliotti, G.

    2009-04-01

    Carbon dioxide gas xchange between terrestrial ecosystems and the atmosphere, as well as the carbon sink strength of various arable land ecosystems, is of primary interest for global change research. Measures for increasing soil C inputs include the preferential use of livestock-derived organic materials (e.g. animal manure and slurries, digestate from biogas production plants and compost). The application of such materials to agricultural soils returns essential nutrients for plant growth and organic matter to maintain long-term fertility. Whether or not such practices ultimately result in sustained C sequestration at the ecosystem level will depend on their mineralization rates. This work presents preliminary results from a laboratory incubation trial to evaluate carbon dioxide fluxes from two agricultural soils (a calcareous silt loam and a silty clay loam) amended with agricultural doses of (i) pig slurry (PSL), (ii) the digestate from the anaerobic fermentation of pig slurries (AAS) and (ii) a compost from the aerobic stabilisation of the digestate (LDC). These subsequent steps of slurry stabilisation resulted in a decrease in the content of labile organic matter which was reflected in a reduction in maximum carbon dioxide emission rates from amended soils. Measurements have shown that peak emissions from soils occur immediately after application of these organic materials (within 5 days) and decrease in the order PSL > AAS > LDC. Moreover, mean cumulative emissions over the first 40 days showed that a higher percentage (about 44%) of the C added with PSL was mineralised respect to C added with AAS (39%) and LDC (25%). Although it was hypothesised that apart from the quantity and stability of the added organic materials, even soil characteristics could influence C mineralisation rates, no significant differences were observed between emission fluxes for similarly treated soils. Mean cumulative emission fluxes after 40 days from treatment were of 114, 103 and

  3. 75 FR 80455 - Certain Hot-Rolled Carbon Steel Flat Products From India: Amended Final Results of Countervailing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-22

    ... International Trade Administration Certain Hot-Rolled Carbon Steel Flat Products From India: Amended Final... administrative review of the countervailing duty order on certain hot-rolled carbon steel flat products (HRCS... review of HRCS from India covering the POR of January 1, 2006, through December 31, 2006. See Certain...

  4. 76 FR 77775 - Certain Hot-Rolled Carbon Steel Flat Products From India: Amended Final Results of Countervailing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... International Trade Administration Certain Hot-Rolled Carbon Steel Flat Products From India: Amended Final... administrative review of the countervailing duty order on certain ] hot-rolled carbon steel flat products (HRCS... of HRCS from India covering the POR of January 1, 2008, through December 31, 2008. See Certain...

  5. 75 FR 73033 - Circular Welded Carbon Steel Pipes and Tubes from Thailand: Amended Final Results of Antidumping...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-29

    ... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes from Thailand: Amended Final... steel pipes and tubes (pipes and tubes) from Thailand, covering the period March 1, 2008 through... published in the Federal Register on October 20, 2010. See Circular Welded Carbon Steel Pipes and Tubes...

  6. Carbon stabilization and microbial growth in acidic mine soils after addition of different amendments for soil reclamation

    NASA Astrophysics Data System (ADS)

    Zornoza, Raúl; Acosta, Jose; Ángeles Muñoz, María; Martínez-Martínez, Silvia; Faz, Ángel; Bååth, Erland

    2016-04-01

    The extreme soil conditions in metalliferous mine soils have a negative influence on soil biological activity and therefore on soil carbon estabilization. Therefore, amendments are used to increase organic carbon content and activate microbial communities. In order to elucidate some of the factors controlling soil organic carbon stabilization in reclaimed acidic mine soils and its interrelationship with microbial growth and community structure, we performed an incubation experiment with four amendments: pig slurry (PS), pig manure (PM) and biochar (BC), applied with and without marble waste (MW; CaCO3). Results showed that PM and BC (alone or together with MW) contributed to an important increment in recalcitrant organic C, C/N ratio and aggregate stability. Bacterial and fungal growths were highly dependent on pH and labile organic C. PS supported the highest microbial growth; applied alone it stimulated fungal growth, and applied with MW it stimulated bacterial growth. BC promoted the lowest microbial growth, especially for fungi, with no significant increase in fungal biomass. MW+BC increased bacterial growth up to values similar to PM and MW+PM, suggesting that part of the biochar was degraded, at least in short-term mainly by bacteria rather than fungi. PM, MW+PS and MW+PM supported the highest microbial biomass and a similar community structure, related with the presence of high organic C and high pH, with immobilization of metals and increased soil quality. BC contributed to improved soil structure, increased recalcitrant organic C, and decreased metal mobility, with low stimulation of microbial growth.

  7. Linking the Belowground Microbial Composition, Diversity and Activity to Soilborne Disease Suppression and Growth Promotion of Tomato Amended with Biochar

    PubMed Central

    Jaiswal, Amit K.; Elad, Yigal; Paudel, Indira; Graber, Ellen R.; Cytryn, Eddie; Frenkel, Omer

    2017-01-01

    Biochar, in addition to sequestering carbon, ameliorating soil, and improving plant performance, can impact foliar and soilborne plant diseases. Nevertheless, the mechanisms associated with suppression of soilborne diseases and improved plant performances are not well understood. This study is designed to establish the relationships between biochar-induced changes in rhizosphere microbial community structure, taxonomic and functional diversity, and activity with soilborne disease suppression and enhanced plant performance in a comprehensive fashion. Biochar suppressed Fusarium crown and root-rot of tomato and simultaneously improved tomato plant growth and physiological parameters. Furthermore, biochar reduced Fusarium root colonization and survival in soil, and increased the culturable counts of several biocontrol and plant growth promoting microorganisms. Illumina sequencing analyses of 16S rRNA gene revealed substantial differences in rhizosphere bacterial taxonomical composition between biochar-amended and non-amended treatments. Moreover, biochar amendment caused a significant increase in microbial taxonomic and functional diversity, microbial activities and an overall shift in carbon-source utilization. High microbial taxonomic and functional diversity and activity in the rhizosphere has been previously associated with suppression of diseases caused by soilborne pathogens and with plant growth promotion, and may collectively explain the significant reduction of disease and improvement in plant performance observed in the presence of biochar. PMID:28287177

  8. Linking the Belowground Microbial Composition, Diversity and Activity to Soilborne Disease Suppression and Growth Promotion of Tomato Amended with Biochar.

    PubMed

    Jaiswal, Amit K; Elad, Yigal; Paudel, Indira; Graber, Ellen R; Cytryn, Eddie; Frenkel, Omer

    2017-03-13

    Biochar, in addition to sequestering carbon, ameliorating soil, and improving plant performance, can impact foliar and soilborne plant diseases. Nevertheless, the mechanisms associated with suppression of soilborne diseases and improved plant performances are not well understood. This study is designed to establish the relationships between biochar-induced changes in rhizosphere microbial community structure, taxonomic and functional diversity, and activity with soilborne disease suppression and enhanced plant performance in a comprehensive fashion. Biochar suppressed Fusarium crown and root-rot of tomato and simultaneously improved tomato plant growth and physiological parameters. Furthermore, biochar reduced Fusarium root colonization and survival in soil, and increased the culturable counts of several biocontrol and plant growth promoting microorganisms. Illumina sequencing analyses of 16S rRNA gene revealed substantial differences in rhizosphere bacterial taxonomical composition between biochar-amended and non-amended treatments. Moreover, biochar amendment caused a significant increase in microbial taxonomic and functional diversity, microbial activities and an overall shift in carbon-source utilization. High microbial taxonomic and functional diversity and activity in the rhizosphere has been previously associated with suppression of diseases caused by soilborne pathogens and with plant growth promotion, and may collectively explain the significant reduction of disease and improvement in plant performance observed in the presence of biochar.

  9. Survival of Salmonella or Escherichia coli O157:H7 during holding of manure-based compost mixtures at sublethal temperatures as influenced by the carbon amendment.

    PubMed

    Erickson, Marilyn C; Smith, Chris; Jiang, Xiuping; Flitcroft, Ian D; Doyle, Michael P

    2015-02-01

    During the early phases of aerobic composting of animal manures, pathogens are inactivated primarily from the accumulation of heat produced by indigenous microbial activity. When compost materials are not exposed to these lethal temperatures, the required holding time needed to obtain a pathogen-free product that may be applied to fields is unknown. Consequently, a series of studies examined whether the carbon amendment (wheat straw, peanut hulls, rice hulls, and pine needles) added to animal manures affected survival of either Salmonella or E. coli O157:H7 during storage of compost mixtures at sublethal temperatures (20 to 40°C). Pathogens consistently survived for longer periods of time in compost mixtures prepared with pine needles than compost mixtures prepared with either of the other three carbon amendments. Pathogen inactivation in wheat straw- or peanut hull-amended compost mixtures was dependent on the target pathogen, moisture level, and storage temperature. Moisture levels in wheat straw-amended compost mixtures stored at 40°C had no effect on inactivation of E. coli O157:H7. In contrast, wheat straw-amended mixtures stored at 30 to 35°C and equilibrated to suboptimal moisture contents (30 to 40%) were less effective for inactivating pathogens compared with drier (25% moisture) or moister (60% moisture) mixtures. In peanut hull-amended compost mixtures, inactivation of E. coli O157:H7 was affected minimally by moisture levels, whereas Salmonella survival increased as the moisture level was decreased. The different inactivation responses of Salmonella and E. coli O157:H7 in compost mixtures prepared with wheat straw or peanut hulls and equilibrated to different moisture levels suggest that there are different mechanisms for inactivation. Hence, developing reliable guidelines relying on time-temperature for holding of compost mixtures at sublethal temperatures will be challenging and, perhaps, not possible.

  10. Dynamics of carbon, nitrogen and phosphorus in soil amended with irradiated, pasteurized and limed biosolids.

    PubMed

    Franco-Hernández, Olivia; Mckelligan-Gonzalez, Alba Natalia; Lopez-Olguin, Ana Maria; Espinosa-Ceron, Fabiola; Escamilla-Silva, Eleazar; Dendooven, Luc

    2003-03-01

    Sewage biosolids contain high concentrations of pathogens, which limits their use as soil amendment. This study investigated how application of lime (Ca(OH)2), irradiation, or pasteurization reduced pathogens in biosolids and how its application affected soil characteristics. A soil sampled outside the canopy of Mesquite trees (Prosopis laevigata) and from a pasture at Lerma (Mexico) was amended with treated or untreated biosolids, characterized and incubated aerobically while dynamics of carbon (C), nitrogen (N) and phosphorus (P) were monitored. Heavy metals concentrations in the biosolids were low, so it was of excellent quality (USEPA). The amount of pathogens in the biosolids made it a class "B" (USEPA) which can be used in forests. Only irradiation sufficiently reduced faecal coliforms to make it a class "A" biosolids without restrictions in application. C mineralization increased significantly when biosolids were added, but not concentrations of available P (P < 0.05). Ammonium (NH4+) concentrations in soil amended with biosolids were higher compared to unamended soil, but not the concentrations of nitrate (NO3-) except when biosolids treated with Ca(OH)2 was added to the Lerma soil.

  11. Evaluation-of soil enzyme activities as soil quality indicators in sludge-amended soils.

    PubMed

    Dindar, Efsun; Şağban, Fatma Olcay Topaç; Başkaya, Hüseyin Savaş

    2015-07-01

    Soil enzymatic activities are commonly used as biomarkers of soil quality. Several organic and inorganic compounds found in municipal wastewater sludges can possibly be used as fertilizers. Monitoring and evaluating the quality of sludge amended soils with enzyme activities accepted as a beneficial practice with respect to sustainable soil management. In the present study, variation of some enzyme activities (Alkaline phosphatase, dehydrogenase, urease and beta-glucosidase activities) in soils amended with municipal wastewater sludge at different application rates (50, 100 and 200 t ha(-1) dry sludge) was evaluated. Air dried sludge samples were applied to soil pots and sludge-soil mixtures were incubated during a period of three months at 28 degrees C. The results of the study showed that municipal wastewater sludge amendment apparently increased urease, dehydrogenase, alkaline phosphatase and P-glucosidase activities in soil by 48-70%, 14-47%, 33-66% and 9-14%, respectively. The maximum activity was generally observed in sludge amended soil with dose of 200 t ha(-1). Urease activity appeared to be a better indicator of soil enhancement with wastewater sludge, as its activity was more strongly increased by sludge amendment. Accordingly, urease activity is suggested to be soil quality indicator best suited for measuring existing conditions and potential changes in sludge-amended soil.

  12. Influence of carbon and buffer amendment on ammonia volatilization in composting.

    PubMed

    Liang, Y; Leonard, J J; Feddes, J J R; McGill, W B

    2006-03-01

    Laboratory-scale experiments were carried out to test a mathematical model of the nitrogen dynamics in a composting process. The main ingredients of composting materials were wheat straw and dairy manure. The influence of (a) two carbon amendments, i.e. molasses and office paper, and (b) two chemicals forming buffer solutions on ammonia volatilization were investigated. Nitrogen losses amounted to 12-25% of initial nitrogen, in which ammonia volatilization accounted for 60-99%. Addition of molasses, a readily available form of carbon, reduced cumulative ammonia emissions substantially, but office paper, i.e. cellulose, had only a small influence. The addition of buffering chemicals did not significantly reduce ammonia volatilization.

  13. Impact of activated carbon, biochar and compost on the desorption and mineralization of phenanthrene in soil.

    PubMed

    Marchal, Geoffrey; Smith, Kilian E C; Rein, Arno; Winding, Anne; Wollensen de Jonge, Lis; Trapp, Stefan; Karlson, Ulrich G

    2013-10-01

    Sorption of PAHs to carbonaceous soil amendments reduces their dissolved concentrations, limiting toxicity but also potentially biodegradation. Therefore, the maximum abiotic desorption of freshly sorbed phenanthrene (≤5 mg kg(-1)) was measured in three soils amended with activated carbon (AC), biochar or compost. Total amounts of phenanthrene desorbed were similar between the different soils, but the amendment type had a large influence. Complete desorption was observed in the unamended and compost amended soils, but this reduced for biochar (41% desorbed) and AC (8% desorbed). Cumulative amounts mineralized were 28% for the unamended control, 19% for compost, 13% for biochar and 4% for AC. Therefore, the effects of the amendments in soil in reducing desorption were also reflected in the extents of mineralization. Modeling was used to analyze key processes, indicating that for the AC and charcoal treatments bacterial activity did not limit mineralization, but rather desorption into the dissolved phase.

  14. 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.

  15. 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.

  16. Impact of biochar amendment on soil water soluble carbon in the context of extreme hydrological events.

    PubMed

    Wang, Daoyuan; Griffin, Deirdre E; Parikh, Sanjai J; Scow, Kate M

    2016-10-01

    Biochar amendments to soil have been promoted as a low cost carbon (C) sequestration strategy as well as a way to increase nutrient retention and remediate contaminants. If biochar is to become part of a long-term management strategy, it is important to consider its positive and negative impacts, and their trade-offs, on soil organic matter (SOM) and soluble C under different hydrological conditions such as prolonged drought or frequent wet-dry cycles. A 52-week incubation experiment measuring the influence of biochar on soil water soluble C under different soil moisture conditions (wet, dry, or wet-dry cycles) indicated that, in general, dry and wet-dry cycles increased water soluble C, and biochar addition further increased release of water soluble C from native SOM. Biochar amendment appeared to increase transformation of native SOM to water soluble C, based on specific ultraviolet absorption (SUVA) and C stable isotope composition; however, the increased amount of water soluble C from native SOM is less than 1% of total biochar C. The impacts of biochar on water soluble C need to be carefully considered when applying biochar to agricultural soil.

  17. 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.

  18. Using cyclic steps on drift wedges to amend established models of carbonate platform slopes

    NASA Astrophysics Data System (ADS)

    Betzler, Christian; Lindhorst, Sebastian; Eberli, Gregor; Reijmer, John; Lüdmann, Thomas

    2015-04-01

    Hydroacoustic and sedimentological data of the western flank of Great Bahama Bank and Cay Sal Bank document how the interplay of offbank sediment export, along-slope transport, and erosion together shape facies and thickness distribution of slope deposits. The integrated data set depicts the combined product of these processes and allows formulating a comprehensive model of a periplatform drift that significantly amends established models of carbonate platform slope facies distribution and geometry. The basinward thinning wedge of the periplatform drift at the foot of the escarpment of Great Bahama Bank displays along- and down-slope variations in sedimentary architecture. Sediments consist of periplatform ooze, i.e. carbonate mud and muddy carbonate sand, coarsening basinward. In zones of lower contour current speed, depth related facies belts develop. In the upper part of the periplatform drift wedge in a water depth of 180 to 300 m and slope angles of 6° - 9° the seafloor displays a smooth surface. Parasound data indicate that this facies is characterized by a parallel layering. Basinward, the slope shows a distinct break at which the seafloor inclination diminishes to 1° to 2°. Downslope of this break, the drift wedge has a 3 - 4 km wide pervasive cover of bedforms down to a water depth of around 500 m. The steep flanks and internal stratification of the wavy bedforms face upslope, indicating upstream migration; the bedforms therefore share all the characteristics of cyclic step sedimentation. This is the first description of cyclic step sedimentation patterns in carbonate slope depositional systems. This new slope sedimentation model aids in understanding the complexity of carbonate slope sedimentation models with facies belts perpendicular and parallel to the platform margin. The new model sharply contrasts with existing slope facies models in which facies belts are solely positioned parallel to the platform margin.

  19. 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.

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

    EPA Science Inventory

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

  1. Amending the Amendments

    ERIC Educational Resources Information Center

    McNamara, William

    1976-01-01

    Reviews activity in Congress, federal agencies, and higher education associations as legislation to extend and improve the 1972 Higher Education Amendments is being fashioned. Issues include a public vs. private debate regarding use of the Basic Opportunity Grant program (BOG) to foster access as opposed to choice among institutions. (JT)

  2. [Effects of earthworm inoculation and straw amendment on soil microflora and microbial activity in Cu contaminated soil].

    PubMed

    Wang, Dan-dan; Li, Hui-xin; Wei, Zheng-gui; Liu, Man-qiang; Wang, Xia; Hu, Feng

    2007-05-01

    In this paper, the dynamics of microflora and microbial activity in soil added with 0, 100, 200 and 400 mg x kg(-1) of Cu2+ were studied under effects of inoculating earthworm and applying straw. Four treatments were installed, i.e., CK, surface application of straw (M), inoculation of earthworm (E), and M plus E (ME). The results showed that Cu contamination had inhibitory effect on soil bacteria and actinomycetes, but no effect on soil fungi. Straw amendment increased soil fungi significantly, while earthworm inoculation could increase the numbers of soil bacteria and actinomycetes significantly but had little effect on soil fungi. When the Cu concentration was higher than 200 mg x kg(-1, soil microbial biomass carbon was depressed, but earthworm inoculation and straw amendment could enhance it, with most significant effect under the combination of these two treatments. Earthworm inoculation and straw amendment could enhance soil basal respiration markedly. When the Cu concentration was lower than 200 mg x kg(-1), treatment M had the highest soil basal respiration, being about 3.06-5.58 times higher than that of CK, while at Cu > or =200 mg x kg(-1), soil qCO2 followed the sequence of ME > E > M > CK. Treatments M and E had no effects on soil NH4+ -N. As for soil NO3- -N, treatment E could increase it significantly, but treatment M was in adverse. Treatment ME induced the lowest soil NO3- -N. In a definite degree, earthworm inoculation and straw amendment could mitigate the negative impact of Cu contamination on soil microflora and microbial activity.

  3. Factors driving the carbon mineralization priming effect in a sandy loam soil amended with different types of biochar

    NASA Astrophysics Data System (ADS)

    Cely, P.; Tarquis, A. M.; Paz-Ferreiro, J.; Méndez, A.; Gascó, G.

    2014-06-01

    The effect of biochar on the soil carbon mineralization priming effect depends on the characteristics of the raw materials, production method and pyrolysis conditions. The goal of the present study is to evaluate the impact of three different types of biochar on physicochemical properties and CO2 emissions of a sandy loam soil. For this purpose, soil was amended with three different biochars (BI, BII and BIII) at a rate of 8 wt% and soil CO2 emissions were measured for 45 days. BI is produced from a mixed wood sieving from wood chip production, BII from a mixture of paper sludge and wheat husks and BIII from sewage sludge. Cumulative CO2 emissions of biochars, soil and amended soil were well fit to a simple first-order kinetic model with correlation coefficients (r2) greater than 0.97. Results show a negative priming effect in the soil after addition of BI and a positive priming effect in the case of soil amended with BII and BIII. These results can be related to different biochar properties such as carbon content, carbon aromaticity, volatile matter, fixed carbon, easily oxidized organic carbon or metal and phenolic substance content in addition to surface biochar properties. Three biochars increased the values of soil field capacity and wilting point, while effects over pH and cation exchange capacity were not observed.

  4. Dynamics of carbon, nitrogen and hydrocarbons in diesel-contaminated soil amended with biosolids and maize.

    PubMed

    Rivera-Espinoza, Y; Dendooven, L

    2004-01-01

    Contamination of soil with hydrocarbons occurs frequently when petroleum ducts are damaged. Restoration of those contaminated soils might be achieved by applying readily available organic material. An uncontaminated clayey soil sampled in the vicinity of a duct carrying diesel which ruptured recently, was contaminated in the laboratory and amended with or without maize or biosolids while production of carbon dioxide (CO(2)), dynamics of ammonia (NH(4)(+)), nitrates (NO(3)(-)), and total petroleum hydrocarbons (TPH) were monitored. The fastest mineralization of diesel, as witnessed by production of CO(2), was found when biosolids were added, but the amount mineralized after 100 days, approximately 88%, was similar in all treatments. Approximately 5 mg of the 48 mg TPH kg(-1) found in the sterilized soil at the beginning of the experiment could not be accounted for after 100 days. The concentration of TPH in the unsterilized soil decreased rapidly in all treatments, but the rate of decrease was different between the treatments. The fastest decrease was found in the soil amended with biosolids and approximately 30 mg TPH kg(-1) or 60% could not be accounted for within 7 days. The decrease in concentration of TPH at the onset of the incubation was similar in the other treatments. After 100 days, the concentration of TPH was similar in all soils and appear to stabilize at 19 mg TPH kg(-1) soil. It was concluded that biosolids accelerated the decomposition of diesel and TPH due to its large nutrient content, but after 100 days the amount of diesel mineralized and the residual concentration of TPH was not affected by the treatment applied.

  5. Long Term Amendment with Fresh and Composted Solid Olive Mill Waste on Olive Grove Affects Carbon Sequestration by Prunings, Fruits, and Soil

    PubMed Central

    Regni, Luca; Nasini, Luigi; Ilarioni, Luana; Brunori, Antonio; Massaccesi, Luisa; Agnelli, Alberto; Proietti, Primo

    2017-01-01

    The soil amendment with organic wastes represents a way to increase the soil fertility and the organic carbon (C) stored in the agro-ecosystems. Among the organic waste materials produced by agricultural and industrial activities, olive mill wastes derived from the olive oil extraction process may represent a suitable soil amendment. The aim of the study was to evaluate the effect of fresh (SOMW) or composted mixture of SOMW and shredded olive tree prunings (C-SOMW+P) on the vegetative and productive activities of olive trees, on the C stored in the tree non-permanent structures (prunings and fruits) and in the soil. The plots treated with SOMW or C-SOMW+P showed higher vegetative and productive activities than the untreated plots, and this was attributed to the higher total N and availability of P and K supplied by the amendments. Consequently, treatments increased the C sequestered in the tree non-permanent structures than in the control trees. However, no significant different effect between SOMW and C-SOMW+P treatments was found for the C stored in prunings and fruits, whereas it was evident a stronger influence of C-SOMW+P than SOMW on soil C sequestration. Indeed, about 50% the C supplied by the treatment with C-SOMW+P was sequestered in the olive grove system, with more than 90% of the sequestered C stored into the soil. The low amount of C sequestered in the soil following the addition of SOMW was attributed to its richness of moisture and easily degradable compounds that triggered the mineralization processes controlled by the soil microbial community. Although the 8 years of amendment produced a higher fruit yields than the control, no difference occurred between the characteristics and the oil content of the olive fruits. Only the total phenol content for the oil obtained from the SOMW-treated plots was significantly higher. The other considered fruit characteristics did not show significant differences. PMID:28119719

  6. Effects of carbon amendment on in situ atrazine degradation and total microbial biomass.

    PubMed

    Ngigi, Anastasiah N; Getenga, Zachary M; Dörfler, Ulrike; Boga, Hamadi I; Kuria, Benson; Ndalut, Paul; Schroll, Reiner

    2013-01-01

    This study elucidates the effects of carbon amendment on metabolic degradation of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine) and total microbial biomass in soil. Degradation of (14)C-ring-labelled atrazine was monitored in laboratory incubations of soils supplemented with 0, 10, 100 and 1000 μg g(-1) sucrose concentrations. An experiment to determine the effect of carbon amendment on total microbial biomass and soil respiration was carried out with different concentrations of sucrose and non-labelled atrazine. The soils were incubated at a constant temperature and constant soil moisture at water potential of -15 kPa and a soil density of 1.3 g cm(-3). Mineralization of (14)C-ring-labelled atrazine was monitored continuously over a period of 59 d in the first experiment. The CO(2) production was monitored for 62 d in the second experiment and microbial biomass determined at the end of the incubation period. The addition of 1000 μg g(-1) sucrose reduced atrazine mineralization to 43.5% compared to 51.7% of the applied amount for the treatment without sucrose. The addition of 1000 μg g(-1) sucrose modified the transformation products to 1.08 μg g(-1) deisopropylatrazine (DIA), 0.32 μg g(-1) desethylatrazine (DEA) and 0.18 μg g(-1) deisopropyl-2-hydroxyatrazine (OH-DIA). Treatment without sucrose resulted in formation of 0.64 μg g(-1) hydroxyatrazine (HA), 0.28 μg g(-1) DIA and 0.20 μg g(-1) OH-DIA. Atrazine dealkylation was enhanced in treatments with 100 and 1000 μg g(-1) of sucrose added. HA metabolite was formed in the control (no sucrose) and in the presence of 10 μg g(-1) of sucrose, whereas DEA was only detected in treatment with 1000 μg g(-1) sucrose. Results indicate that total microbial biomass increased significantly (P < 0.001) with the addition of 1000 μg g(-1) sucrose.

  7. Soluble organic carbon and pH of organic amendments affect metal mobility and chemical speciation in mine soils.

    PubMed

    Pérez-Esteban, Javier; Escolástico, Consuelo; Masaguer, Alberto; Vargas, Carmen; Moliner, Ana

    2014-05-01

    We evaluated the effects of pH and soluble organic carbon affected by organic amendments on metal mobility to find out the optimal conditions for their application in the stabilization of metals in mine soils. Soil samples (pH 5.5-6.2) were mixed with 0, 30 and 60 th a(-1) of sheep-horse manure (pH 9.4) and pine bark compost (pH 5.7). A single-step extraction procedure was performed using 0.005 M CaCl2 adjusted to pH 4.0-7.0 and metal speciation in soil solution was simulated using NICA-Donnan model. Sheep-horse manure reduced exchangeable metal concentrations (up to 71% Cu, 75% Zn) due to its high pH and degree of maturity, whereas pine bark increased them (32% Cu, 33% Zn). However, at increasing dose and hence pH, sheep-horse manure increased soluble Cu because of higher soluble organic carbon, whereas soluble Cu and organic carbon increased at increasing dose and correspondingly decreasing pH in pine bark and non-amended treatments. Near the native pH of these soils (at pH 5.8-6.3), with small doses of amendments, there was minimum soluble Cu and organic carbon. Pine bark also increased Zn solubility, whereas sheep-horse manure reduced it as soluble Zn always decreased with increasing pH. Sheep-horse manure also reduced the proportion of free metals in soil solution (from 41% to 4% Cu, from 97% to 94% Zn), which are considered to be more bioavailable than organic species. Sheep-horse manure amendment could be efficiently used for the stabilization of metals with low risk of leaching to groundwater at low doses and at relatively low pH, such as the native pH of mine soils.

  8. 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.

  9. 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.

  10. Enhancing carbon and nitrogen sequestration in reclaimed soils through organic amendments and chiseling

    SciTech Connect

    Shrestha, R.K.; Lal, R.; Jacinthe, P.A.

    2009-05-15

    The choice of reclamation techniques could affect restoration success, ecosystem productivity, and the capacity of reclaimed mine soil (RMS) to sequester soil organic carbon (SOC). A field experiment was conducted at three reclaimed coal mine sites across eastern Ohio to assess the impact of several reclamation techniques on biomass production, soil properties, and temporal changes in SOC and N pools. Amendments and reclamation practices tested were: normal reclamation practice (NRP, control), cow (Bos taurus) manure (10 Mg ha{sup -1}), mulching with oat straw (15 Mg hat), and chiseling (30-cm depth). At each site, all treatments were applied in triplicate to experimental plots in accord with a randomized complete block design. After 5 yr of restoration, results showed no effect of mulching on any of the soil properties investigated but significant effects of manuring and chiseling. During that period, SOC sequestration rates ranged between 0.6 and 2.8 Mg C ha{sup -1} yr{sup -1}, with the highest rates recorded in the manure-treated plots. Aboveground biomass production, biomass N content, and soil N and SOC pools were also significantly higher in the manure and chiseling treatments, probably due to greater exploration of the soil volume by plant roots and more efficient uptake of water and available nutrients. Ecosystem C (SOC + biomass C) in these two treatments also exceeded that in the NRP by 25 to 27 Mg C ha{sup -}. Thus, manure application and chiseling are effective reclamation practices for restoring RMS.

  11. Biochemical activity and chemical-structural properties of soil organic matter after 17 years of amendments with olive-mill pomace co-compost.

    PubMed

    Aranda, V; Macci, C; Peruzzi, E; Masciandaro, G

    2015-01-01

    This study evaluates soil fertility, biochemical activity and the soil's ability to stabilize organic matter after application of composted olive-mill pomace. This organic amendment was applied in two different olive groves in southern Spain having different soil typologies (carbonated and silicic). Olive grove soils after 17 years of organic management with application of olive-mill pomace co-compost were of higher quality than those with conventional management where no co-compost had been applied. The main chemical parameters studied (total organic carbon, total nitrogen, available phosphorus, exchangeable bases, cation exchange capacity, total extractable carbon (TEC), and humic-to-fulvic acids ratio), significantly increased in soils treated with the organic amendment. In particular, the more resistant pool of organic matter (TEC) enhanced by about six and eight fold in carbonated and silicic soils, respectively. Moreover, the amended silicic soils showed the most significant increases in enzyme activities linked to C and P cycles (β-glucosidase twenty-five fold higher and phosphatase seven fold higher). Organic management in both soils induced higher organic matter mineralization, as shown by the higher pyrrole/phenol index (increasing 40% and 150% in carbonated and silicic soils, respectively), and lower furfural/pyrrole index (decreasing 27% and 71% in carbonated and silicic soils, respectively). As a result of mineralization, organic matter incorporated was also more stable as suggested by the trend of the aliphatic/aromatic index (decreasing 36% and 30% in carbonated and silicic soils, respectively). Therefore, management system and soil type are key factors in increasing long-term C stability or sequestration in soils. Thus application of olive-oil extraction by-products to soils could lead to important mid-to -long-term agro-environmental benefits, and be a valuable alternative use for one of the most widespread polluting wastes in the Mediterranean

  12. Transport and attenuation of metal(loid)s in mine tailings amended with organic carbon: Column experiments

    NASA Astrophysics Data System (ADS)

    Lindsay, Matthew B. J.; Blowes, David W.; Ptacek, Carol J.; Condon, Peter D.

    2011-07-01

    A laboratory-scale column experiment was conducted to evaluate the effect of organic carbon amendments on the mobility of As, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Tl and Zn in mine tailings. Three columns were packed with sulfide- and carbonate-rich tailings, which were amended with a 1:1 (vol.) mixture of peat and spent brewing grain at proportions of 0, 2 and 5 vol. %. A simulated input solution characterized by circumneutral pH and elevated concentrations of SO 4 and S 2O 3 was passed through the columns for 540 days. The input solution contained low concentrations of metal(loid)s during the initial 300 days and elevated concentrations thereafter. Decreases in mass transport of S 2O 3 were observed in all columns; with increased attenuation observed at 5 vol. % organic carbon content. Removal of Mn, Ni, Cu, Sb and Mo was observed in all columns during the initial 300 days. However, during this time, mobilization of Fe, As, Zn and Pb was observed, with the greatest increases in concentration observed at the higher organic carbon content. During the final 240 days, S 2O 3 removal was enhanced in columns containing organic carbon, and Fe, Mn, Ni, Tl, As and Sb removal also was observed. This study demonstrates the influence of organic carbon amendments on metal(loid) mobility in mine tailings. Decreases in mass discharge of metal(loid)s may be achieved using this technique; however, site-specific geochemical conditions must be considered before field-scale implementation.

  13. Reconciling apparent variability in effects of biochar amendment on soil enzyme activities by assay optimization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We studied the effects of a biochar made from switchgrass on four soil enzymes (ß- glucosidase, ß-N-acetylglucosaminidase, lipase, and leucine aminopeptidase) to determine if biochar would consistently modify soil biological activities. Inconsistent results from enzyme assays of char-amended soils s...

  14. A PERMEABLE ACTIVE AMENDMENT CONCRETE (PAAC) FOR CONTAMINANT REMEDIATION AND EROSION CONTROL

    SciTech Connect

    Knox, A.; Paller, M.; Dixon, K.

    2012-06-29

    The final project report for SEED SERDP ER - 2134 describes the development of permeable active amendment concrete (PAAC), which was evaluated through four tasks: 1) development of PAAC; 2) assessment of PAAC for contaminant removal; 3) evaluation of promising PAAC formulations for potential environmental impacts; and 4) assessment of the hydraulic, physical, and structural properties of PAAC. Conventional permeable concrete (often referred to as pervious concrete) is concrete with high porosity as a result of an extensive and interconnected void content. It is made from carefully controlled amounts of water and cementitious materials used to create a paste that forms a coating around aggregate particles. The mixture has a substantial void content (e.g., 15% - 25%) that results in a highly permeable structure that drains quickly. In PAAC, the aggregate material is partly replaced by chemically-active amendments that precipitate or adsorb contaminants in water that flows through the concrete interstices. PAAC combines the relatively high structural strength, ample void space, and water permeability of pervious concrete with the contaminant sequestration ability of chemically-active amendments to produce a new material with superior durability and ability to control contaminant mobility. The high surface area provided by the concrete interstices in PAAC provides significant opportunity for contaminants to react with the amendments incorporated into the concrete matrix. PAAC has the potential to immobilize a large variety of organic and inorganic contaminants by incorporating different active sequestering agents including phosphate materials (rock phosphate), organoclays, zeolite, and lime individually or in combinations.

  15. 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.

  16. 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

  17. Carbon flux from plants to soil microbes is highly sensitive to nitrogen addition and biochar amendment

    NASA Astrophysics Data System (ADS)

    Kaiser, C.; Solaiman, Z. M.; Kilburn, M. R.; Clode, P. L.; Fuchslueger, L.; Koranda, M.; Murphy, D. V.

    2012-04-01

    The release of carbon through plant roots to the soil has been recognized as a governing factor for soil microbial community composition and decomposition processes, constituting an important control for ecosystem biogeochemical cycles. Moreover, there is increasing awareness that the flux of recently assimilated carbon from plants to the soil may regulate ecosystem response to environmental change, as the rate of the plant-soil carbon transfer will likely be affected by increased plant C assimilation caused by increasing atmospheric CO2 levels. What has received less attention so far is how sensitive the plant-soil C transfer would be to possible regulations coming from belowground, such as soil N addition or microbial community changes resulting from anthropogenic inputs such as biochar amendments. In this study we investigated the size, rate and sensitivity of the transfer of recently assimilated plant C through the root-soil-mycorrhiza-microbial continuum. Wheat plants associated with arbuscular mycorrhizal fungi were grown in split-boxes which were filled either with soil or a soil-biochar mixture. Each split-box consisted of two compartments separated by a membrane which was penetrable for mycorrhizal hyphae but not for roots. Wheat plants were only grown in one compartment while the other compartment served as an extended soil volume which was only accessible by mycorrhizal hyphae associated with the plant roots. After plants were grown for four weeks we used a double-labeling approach with 13C and 15N in order to investigate interactions between C and N flows in the plant-soil-microorganism system. Plants were subjected to an enriched 13CO2 atmosphere for 8 hours during which 15NH4 was added to a subset of split-boxes to either the root-containing or the root-free compartment. Both, 13C and 15N fluxes through the plant-soil continuum were monitored over 24 hours by stable isotope methods (13C phospho-lipid fatty acids by GC-IRMS, 15N/13C in bulk plant

  18. 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.

  19. 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.

  20. 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.

  1. Nitrate removal from agricultural drainage ditch sediments with amendments of organic carbon: Potential for an innovative best management practice

    USGS Publications Warehouse

    Faust, Derek R.; Kröger, Robert; Miranda, Leandro E.; Rush, Scott A.

    2016-01-01

    Agricultural fertilizer applications have resulted in loading of nutrients to agricultural drainage ditches in the Lower Mississippi Alluvial Valley. The purpose of this study was to determine effects of dissolved organic carbon (DOC) and particulate organic carbon (POC) amendments on nitrate-nitrogen (NO3−-N) removal from overlying water, pore water, and sediment of an agricultural drainage ditch. Two experiments were conducted. In experiment 1, control (i.e., no amendment), DOC, and POC treatments were applied in laboratory microcosms for time intervals of 3, 7, 14, and 28 days. In experiment 2, control, DOC, and POC treatments were applied in microcosms at C/N ratios of 5:1, 10:1, 15:1, and 20:1. There were statistically significant effects of organic carbon amendments in experiment 1 (F2,71 = 27.1, P < 0.001) and experiment 2 (F2,53 = 39.1, P < 0.001), time (F1,71 = 14.5, P < 0.001) in experiment 1, and C/N ratio (F1,53 = 36.5, P < 0.001) in experiment 2. NO3−-N removal varied from 60 to 100 % in overlying water among all treatments. The lowest NO3−-N removals in experiment 1 were observed in the control at 14 and 28 days, which were significantly less than in DOC and POC 14- and 28-day treatments. In experiment 2, significantly less NO3−-N was removed in overlying water of the control compared to DOC and POC treatments at all C/N ratios. Amendments of DOC and POC made to drainage ditch sediment: (1) increased NO3−-N removal, especially over longer time intervals (14 to 28 days); (2) increased NO3−-N removal, regardless of C/N ratio; and (3) NO3−-N removal was best at a 5:1 C/N ratio. This study provides support for continued investigation on the use of organic carbon amendments as a best management practice for NO3−-N removal in agricultural drainage ditches.

  2. Modeling organic carbon dynamics and cadmium fate in long-term sludge-amended soil.

    PubMed

    Bergkvist, Petra; Jarvis, Nicholas

    2004-01-01

    A model is described that may help to resolve uncertainty and controversy over the long-term consequences of sludge applications to arable land, especially with regard to the effects of sludge adsorption characteristics on trace metal solubility and bioavailability (e.g., the sludge "time bomb" or sludge "protection" hypotheses). Mass balances of organic and inorganic material derived from sludge and crop residues are simulated. Each pool has a potentially different adsorption affinity for trace metals, and this leads to changes in the adsorption capacity of sludge-amended soil that influence leaching and crop uptake. Model simulations were compared with measured changes in organic carbon and ethylenediaminetetraacetic acid (EDTA)-extractable cadmium contents in a clay loam soil following 41 years of sludge applications. The model adequately reproduced the data, although discrepancies in the vertical distribution of Cd were attributed to the effects of macropore transport and root-uptake driven recirculation. A Monte Carlo sensitivity analysis demonstrated that the most important parameters affecting leaching and crop uptake were the Cd loading and parameters controlling adsorption, especially the partition coefficient for sludge-derived inorganic material and the exponent regulating the effect of pH on sorption. Scenario simulations show that no general conclusions can be drawn with respect to the validity of the sludge "time bomb" and sludge "protection" hypotheses. Either may occur, or neither, depending on three key system parameters: the ratio of sludge adsorption capacity to the initial adsorption capacity of the soil, the proportion of the sludge adsorption capacity contributed by the inorganic fraction, and the sludge Cd loading.

  3. Carbon mineralization in two ultisols amended with different sources and particle sizes of pyrolyzed biochar.

    PubMed

    Sigua, G C; Novak, J M; Watts, D W; Cantrell, K B; Shumaker, P D; Szögi, A A; Johnson, M G

    2014-05-01

    Biochar produced during pyrolysis has the potential to enhance soil fertility and reduce greenhouse gas emissions. The influence of biochar properties (e.g., particle size) on both short- and long-term carbon (C) mineralization of biochar remains unclear. There is minimal information on the potential effects of biochar particle sizes on their breakdowns by soil microorganism, so it is unknown if the particle size of biochar influences C mineralization rate and/or stability in soils. In order to evaluate the effect of different sources (BS) and particle sizes (BF) of biochar on C loss and/or stability in soils, an incubation study on C mineralization of different biochar sources and particle sizes was established using two soils (ST): Norfolk soil (fine loamy, kaolinitic, thermic, typic Kandiudults) and Coxville soil (fine loamy kaolinitic, thermic, Paleaquults). In separate incubation vessels, these soils were amended with one of two manure-based biochars (poultry litters, PL; swine solids, SS) or one of two lignocellulosic-based biochars (switchgrass, SG; pine chips, PC) which were processed into two particle sizes (dust, <0.42 mm; pellet, >2 mm). The amount of CO2 evolved varied significantly between soils (p≤0.0001); particle sizes (p≤0.0001) and the interactions of biochar source (p≤0.001) and forms of biochars (p≤0.0001) with soil types. Averaged across soils and sources of biochar, CO2-C evolved from dust-sized biochar (281 mg kg(-1)) was significantly higher than pellet-sized biochar (226 mg kg(-1)). Coxville soils with SS biochar produced the greatest average CO2-C of 428 mg kg(-1) and Norfolk soils with PC had the lowest CO2-C production (93 mg kg(-1)). Measured rates of carbon mineralization also varied with soils and sources of biochar (Norfolk: PL>SS>SG≥PC; Coxville: PC>SG>SS>PL). The average net CO2-C evolved from the Coxville soils (385 mg kg(-1)) was about threefold more than the CO2-C evolved from the Norfolk soils (123 mg kg(-1)). Our

  4. Removal of triclosan in nitrifying activated sludge: effects of ammonia amendment and bioaugmentation.

    PubMed

    Lee, Do Gyun; Cho, Kun-Ching; Chu, Kung-Hui

    2015-04-01

    This study investigated two possible strategies, increasing ammonia oxidation activity and bioaugmenting with triclosan-degrader Sphingopyxis strain KCY1, to enhance triclosan removal in nitrifying activated sludge (NAS). Triclosan (2 mg L(-1)) was removed within 96-h in NAS bioreactors amended with 5, 25 and 75 mg L(-1) of ammonium (NH4-N). The fastest triclosan removal was observed in 25 mg NH4-NL(-1) amended-bioreactors where high ammonia oxidation occurred. Inhibition of ammonia oxidation and slower triclosan removal were observed in 75 mg NH4-NL(-1) amended-bioreactors. Triclosan removal was correlated to the molar ratio of the amount of nitrate produced to the amount of ammonium removed. Bioaugmentation with strain KCY1 did not enhance triclosan removal in the bioreactors with active ammonia oxidation. Approximately 36-42% and 59% of triclosan added were removed within 24-h by ammonia-oxidizing bacteria and unknown triclosan-degrading heterotrophs, respectively. The results suggested that increasing ammonia oxidation activity can be an effective strategy to enhance triclosan removal in NAS.

  5. Effects of organic dairy manure amendment on soil phosphatase activities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic dairy production is increasing in the U.S. due to concerns over environmental, human, and animal health. It is well known that the application of livestock manure to soil can influence enzyme activities involved in nutrient cycling and soil fertility, such as soil phosphatases; however, orga...

  6. Aminocyclopyrachlor sorption in biochar and activated charcoal amended soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aminocyclopyrachlor is a new herbicide active ingredient, classified as a member of the new chemical class “pyrimidine carboxylic acids”. It is used for control of broadleaf weeds and brush on non-cropland. Due to its potential mobility in some soils, there is interest in whether aminocyclopyrachlor...

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

    PubMed

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

    2016-08-15

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

  8. Technique for surface oxidation of activated carbon

    SciTech Connect

    Sircar, S.; Golden, T.C.

    1987-10-27

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

  9. 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.

  10. Studying the First Amendment.

    ERIC Educational Resources Information Center

    Scales, Pat

    2000-01-01

    Discussion of censorship against books in public and school libraries focuses on intellectual freedom; First Amendment rights; and curriculum development to include lessons on the First Amendment. Offers suggestions for activities focusing on censorship and banned books. (LRW)

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

    PubMed

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

    2006-10-01

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

  12. Effects of glyphosate and foliar amendments on activity of microorganisms in the soybean rhizosphere.

    PubMed

    Means, Nathan E; Kremer, Robert J; Ramsier, Clifford

    2007-02-01

    A field study was conducted to determine the effects of glyphosate on microbial activity in the rhizosphere of glyphosate-resistant (GR) soybean and to evaluate interactions with foliar amendments. Glyphosate at 0.84 kg ae ha(-1) was applied GR soybean at the V4-V5 development stages. Check treatments included a conventional herbicide tank mix (2003 study only) and no herbicides (hand-weeded). Ten days after herbicide application, a commercially available biostimulant and a urea solution (21.0% N) were applied to soybean foliage at 33.5 mL ha(-1) and 9.2 kg ha(-1), respectively. Soil and plant samples were taken 0, 5, 10, 15, 20 and 25 days after herbicide application then assayed for enzyme and respiration activities. Soil respiration and enzyme activity increased with glyphosate and foliar amendment applications during the 2002 growing season; however, similar increases were not observed in 2003. Contrasting cumulative rainfall between 2002 and 2003 likely accounted for differences in soil microbial activities. Increases in soil microbial activity in 2002 suggest that adequate soil water and glyphosate application acted together to increase microbial activity. Our study suggests that general soil microbial properties including those involving C and N transformations are not sensitive enough to detect effects of glyphosate on rhizosphere microbial activity. Measurements of soil-plant-microbe relationships including specific microbial groups (i.e., root-associated Fusarium spp.) are likely better indicators of impacts of glyphosate on soil microbial ecology.

  13. The effect of compost on carbon cycling and the active soil microbiota

    SciTech Connect

    Singer, Esther; Woyke, Tanja; Ryals, Rebecca; Silver, Whendee

    2014-09-02

    Rangelands cover an estimated 40-70percent of global landmass, approximately one-third of the landmass of the United States and half of California. The soils of this vast land area has high carbon (C) storage capacity, which makes it an important target ecosystem for the mitigation of greenhouse gas emission and effects on climate change, in particular under land management techniques that favor increased C sequestration rates. While microbial communities are key players in the processes responsible for C storage and loss in soils, we have barely shed light on these highly complex processes in part due to the tremendous and seemingly intractable diversity of microbes, largely uncultured, that inhabit soil ecosystems. In our study, we compare Mediterranean grassland soil plots that were amended with greenwaste compost in a single event 6 years ago. Subsampling of control and amended plots was performed in depth increments of 0-10 cm. We present data on greenhouse gas emissions and budgets of carbon, nitrogen, phosphorus, and micronutrients in dependence of compost amendment. Changes in the active members of the soil microbial community were assessed using a novel approach combining flow cytometry and 16S tag sequencing disclosing who is active. This is the first study revealing the nature of actively metabolizing microbial community members linked to the geochemical characteristics of compost-amended soil.

  14. Greenhouse gas emission and groundwater pollution potentials of soils amended with raw and carbonized swine solids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research is to study the greenhouse gas emission and groundwater pollution potentials of the soils amended with raw swine solids and swine biochars made from different thermochemical conditions. Triplicate sets of small pots were designed: 1) control soil with a 50/50 mixture o...

  15. Effects of biosolids and compost amendment on chemistry of soils contaminated with copper from mining activities.

    PubMed

    Sidhu, Virinder; Sarkar, Dibyendu; Datta, Rupali

    2016-03-01

    Several million metric tons of mining wastes, called stamp sands, were generated in the Upper Peninsula of Michigan during extensive copper (Cu) mining activities in the past. These materials, containing large amounts of Cu, were discharged into various offshoots of Lake Superior. Due to evidences of Cu toxicity on aquatic organisms, in due course, the materials were dredged and dumped on lake shores, thus converting these areas into vast, fallow lands. Erosion of these Cu-contaminated stamp sands back to the lakes is severely affecting aquatic life. A lack of uniform vegetation cover on stamp sands is facilitating this erosion. Understanding the fact that unless the stamp sands are fertilized to the point of sustaining vegetation growth, the problem with erosion and water quality degradation will continue, amending the stamp sands with locally available biosolids and composts, was considered. The purpose of the reported study was to assess potential effects of such organic fertilizer amendments on soil quality. As the first step of a combined laboratory and greenhouse study, a 2-month-long incubation experiment was performed to investigate the effects of biosolids and compost addition on the soil nutrient profile of stamp sands and organic matter content. Results showed that both biosolids and compost amendments resulted in significant increase in nitrogen and phosphorus concentrations and organic matter contents of stamp sands. Sequential extraction data demonstrated that Cu was mostly present as bound forms in stamp sands, and there was no significant increase in the plant available fraction of Cu because of fertilizer application.

  16. 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.

  17. Regeneration of siloxane-exhausted activated carbon by advanced oxidation processes.

    PubMed

    Cabrera-Codony, Alba; Gonzalez-Olmos, Rafael; Martín, Maria J

    2015-03-21

    In the context of the biogas upgrading, siloxane exhausted activated carbons need to be regenerated in order to avoid them becoming a residue. In this work, two commercial activate carbons which were proved to be efficient in the removal of octamethylcyclotetrasiloxane (D4) from biogas, have been regenerated through advanced oxidation processes using both O3 and H2O2. After the treatment with O3, the activated carbon recovered up to 40% of the original adsorption capacity while by the oxidation with H2O2 the regeneration efficiency achieved was up to 45%. In order to enhance the H2O2 oxidation, activated carbon was amended with iron. In this case, the regeneration efficiency increased up to 92%.

  18. 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.

  19. 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.

  20. Organic Amendments to Avocado Crops Induce Suppressiveness and Influence the Composition and Activity of Soil Microbial Communities

    PubMed Central

    Bonilla, Nuria; Vida, Carmen; Martínez-Alonso, Maira; Landa, Blanca B.; Gaju, Nuria; Cazorla, Francisco M.

    2015-01-01

    One of the main avocado diseases in southern Spain is white root rot caused by the fungus Rosellinia necatrix Prill. The use of organic soil amendments to enhance the suppressiveness of natural soil is an inviting approach that has successfully controlled other soilborne pathogens. This study tested the suppressive capacity of different organic amendments against R. necatrix and analyzed their effects on soil microbial communities and enzymatic activities. Two-year-old avocado trees were grown in soil treated with composted organic amendments and then used for inoculation assays. All of the organic treatments reduced disease development in comparison to unamended control soil, especially yard waste (YW) and almond shells (AS). The YW had a strong effect on microbial communities in bulk soil and produced larger population levels and diversity, higher hydrolytic activity and strong changes in the bacterial community composition of bulk soil, suggesting a mechanism of general suppression. Amendment with AS induced more subtle changes in bacterial community composition and specific enzymatic activities, with the strongest effects observed in the rhizosphere. Even if the effect was not strong, the changes caused by AS in bulk soil microbiota were related to the direct inhibition of R. necatrix by this amendment, most likely being connected to specific populations able to recolonize conducive soil after pasteurization. All of the organic amendments assayed in this study were able to suppress white root rot, although their suppressiveness appears to be mediated differentially. PMID:25769825

  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. [Amendment to the law governing the professional activities of physicians in "Medizinische Versorgungszentren"].

    PubMed

    Siegert, M; von Knoch, M

    2008-02-01

    The amendment to the law governing the professional activities of physicians in general, free practice came into force on 1st January 2007 bringing important changes relevant to medical centres, which were first permitted by the government three years ago. Under the new regulations, for example, medical centres with the status of a private limited company now must provide a guarantee as a condition for the licence to operate. Some of the other most important new regulations include the abolishment of the restriction to practice in one place only and permission for physicians to hold positions in a hospital and a medical centre at the same time.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Soil degradation and amendment effects on soil properties, microbial communities, and plant growth

    NASA Astrophysics Data System (ADS)

    Gebhardt, M.; Fehmi, J. S.; Rasmussen, C.; Gallery, R. E.

    2015-12-01

    Human activities that disrupt soil properties are fundamentally changing ecosystems. Soil degradation, caused by anthropogenic disturbance can decrease microbial abundance and activity, leading to changes in nutrient availability, soil organic matter, and plant establishment. The addition of amendments to disturbed soils have the potential ameliorate these negative consequences. We studied the effects of soil degradation, via an autoclave heat shock method, and the addition of amendments (biochar and woodchips) on microbial activity, soil carbon and nitrogen availability, microbial biomass carbon and nitrogen content, and plant growth of ten plant species native to the semi-arid southwestern US. Relative to non-degraded soils, microbial activity, measured via extracellular enzyme assays, was significantly lower for all seven substrates assayed. These soils also had significantly lower amounts of carbon assimilated into microbial biomass but no change in microbial biomass nitrogen. Soil degradation had no effect on plant biomass. Amendments caused changes in microbial activity: biochar-amended soils had significant increases in potential activity with five of the seven substrates measured; woodchip amended soils had significant increases with two. Soil carbon increased with both amendments but this was not reflected in a significant change in microbial biomass carbon. Biochar-amended soils had increases in soil nitrogen availability but neither amendment caused changes in microbial biomass nitrogen. Biochar amendments had no significant effect on above- or belowground plant biomass while woodchips significantly decreased aboveground plant biomass. Results show that soil degradation decreases microbial activity and changes nutrient dynamics, but these are not reflected in changes in plant growth. Amendments provide nutrient sources and change soil pore space, which cause microbial activities to fluctuate and may, in the case of woodchips, increase plant drought

  11. 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.

  12. Carbon and nitrogen mineralization in a vineyard soil amended with grape marc vermicompost.

    PubMed

    Paradelo, Remigio; Moldes, Ana Belén; Barral, María Teresa

    2011-11-01

    Vineyard soils in many areas suffer from low organic matter contents, which can be the cause of negative effects such as increasing the risk of erosion, so the use of organic amendments must be considered a good agricultural practice. Even more, if grape marc is recycled as a soil amendment in the vineyards, benefits from a good waste management strategy are also obtained. In the present study, a grape marc from the wine region of Valdeorras (north-west Spain) was used for the production of vermicompost, and this added to a vineyard soil of the same area in a laboratory study. Mixtures of soil and grape marc vermicompost (2 and 4%, dry weight) were incubated for ten weeks at 25°C and the mineralization of C and N studied. The respiration data were fitted to a first-order kinetic model. The rates of grape marc vermicompost which should be added to the vineyard soil in order to maintain the initial levels of organic matter were estimated from the laboratory data, and found to be 1.7 t ha(-1) year(-1) of bulk vermicompost (if the present mean temperature is considered) and 2.1 t ha(-1) year(-1) of bulk vermicompost (if a 2°C increment in temperature is considered), amounts which could be obtained recycling the grape marc produced in the exploitation.

  13. Biosolids amendment dramatically increases sequestration of crop residue-carbon in agricultural soils in western Illinois

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Release of carbon dioxide through microbial respiration from the world’s crop residues (non-edible plant parts left in the field after harvest) represents an important form of carbon transfer from terrestrial ecosystems to the atmosphere. We hypothesized that alleviation of environmental stress (moi...

  14. Reconciling Apparent Variability in Effects of Biochar Amendment on Soil Enzyme Activities by Assay Optimization

    SciTech Connect

    Bailey, Vanessa L.; Fansler, Sarah J.; Smith, Jeffery L.; Bolton, Harvey

    2011-02-01

    Applying biochar to soils as an ameliorative substance and mechanism for C sequestration has received a great deal of interest in light of the sustained fertility observed in the Terra Preta soils of Brazil. The effects of synthetic biochars on biochemical processes needs to be better understood in order to determine if this is a reasonable practice in managed systems. The biochar studied was formed from the fast-pyrolysis of a switchgrass feedstock. Four soil enzymes were studied: β-glucosidase, β-N-acetylglucosaminidase, lipase, and leucine aminopeptidase. Both colorimetric and fluorescent assays were used for β-glucosidase and β-N-acetylglucosaminidase. Seven days after biochar was added to microcosms of a Palouse silt loam, the fluorescence-based assays indicated increased activities of the four enzymes, compared to non-amended soil. To clarify the mechanisms of the observed effects,in the absence of soil, purified enzymes or substrates were briefly exposed to biochar and then assayed. Except for β-N-acetylglucosaminidase, the exposure of substrate to biochar reduced the apparent activity of the remaining three enzymes in vitro, suggesting that sorption reactions between the substrate and biochar either removed the substrate from the assays or impeded the enzyme binding. The activity of purified β-N-acetylglucosaminidase increased significantly following biochar exposure, suggesting a chemical stimulation of enzyme functioning. We conclude that biochar added to soil acts as a substrate that can stimulate the soil microbial biomass and its activity. Our in vitro study suggests that biochar is not biochemically inert. Biochar amendments are likely to have effects that are currently difficult to predict, and that could impact overall soil function.

  15. 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

  16. Nitrogen and carbon pools in an agricultural soil amended with natural and NH4-enriched K-Chabazite zeolitite

    NASA Astrophysics Data System (ADS)

    Ferretti, Giacomo; Faccini, Barbara; Vittori Antisari, Livia; Di Giuseppe, Dario; Massimo, Coltorti

    2015-04-01

    Nitrogen and Carbon pools in a reclaimed agricultural soil amended with 5 to 15 Kg m-2 of natural and NH4-enriched (K-Chabazite) zeolitites have been investigated. Zeolitites were enriched by means of static exchange with a swine slurry in a prototype (ZeoLIFE Project, www.zeolife.it). The experimental field is located in the Po Delta plain near Codigoro (Ferrara, Italy), it extends over an area of about 6 ha and it was divided in six parcels. The field has been heavily fertilized with chemical fertilizers and livestock sewage since 1960. Nowadays the area is part of the Nitrate Vulnerable Zones (Nitrate Directive 91/676/CEE) and a maximum annual input of 170 Kg-N ha-1 must be respected. With respect to the control parcels, at the end of the agronomic year, sorghum yield was 4% and 14% higher in the parcels treated with natural zeolitite and in that treated with NH4-enriched zeolitite, respectively. This notwithstanding the N fertilizers reduction from 30% in the former to 50% in the latter. Beside the yield improvement, N and C pools are affected by the use of zeolitite and relevant changes have been noticed. i) δ15N ratios in both soil (total and fixed N-NH4 inside the clay interlayer and zeolite exchange sites) and different organs of the sorghum crops show that the N-NH4 stocked in the enriched zeolitite has been transferred to the crops and preferentially stocked in the leaves with respect to the N-NH4 provided by chemical fertilizer. ii) The active role of fixed N-NH4 pool in mineral nutrition of the crops and its replacement can be due to inorganic N fertilizers (Urea and Diammonium Phosphate). This pool in fact decreased during the crops growth, suggesting that it represented an important contribution to the active N pool in the soil. iii) Due to the high N content in this agricultural field, no significant total N decrease was observed during the growing season, which is also responsible for the low C/N ratio in the soil. After the N input from NH4

  17. 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.

  18. Biochar soil amendment for environmental and agronomic benefits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Char(coal), and a broader term black carbon (that includes soot) has long been recognized as a normal environmental (including soil) constituent resulting from fire and industrial activities. Biochar soil amendment has received global interests as a tool for carbon sequestration in conjunction with...

  19. Stabilization by hydrophobic protection as a molecular mechanism for organic carbon sequestration in maize-amended rice paddy soils.

    PubMed

    Song, X Y; Spaccini, R; Pan, G; Piccolo, A

    2013-08-01

    The hydrophobic components of soil organic matter (SOM) are reckoned to play an important role in the stabilization of soil organic carbon (SOC). The contribution of hydrophobic substances to SOC sequestration was evaluated in four different paddy soils in the South of China, following a 6-month incubation experiment with maize straw amendments. Soil samples included: a well developed paddy soil (TP) derived from clayey lacustrine deposits in the Tai Lake plain of Jiangsu; an acid clayey paddy soil (RP) derived from red earth in the rolling red soil area of Jiangxi; a weakly developed neutral paddy soil (PP) formed on Jurassic purple shale from Chongq; and a calcic Fluvisol (MS) derived from riverine sediments from a wetland along the Yangtze valley of Anhui, China. The SOC molecular composition after 30 and 180 days of incubation, was determined by off-line thermochemolysis followed by gas chromatography-mass spectrometry analysis. Lignin, lipids and carbohydrates were the predominant thermochemolysis products released from the treated soils. A selective preservation of hydrophobic OM, including lignin and lipids, was shown in maize amended soils with prolonged incubation. The decomposition of lignin and lipids was significantly slower in the TP and RP soils characterized by a larger content of extractable iron oxyhydrates (Fed) and lower pH. The overall increase in hydrophobic substances in maize incubated samples was correlated, positively, with total content of clay and Fed, and, negatively, with soil pH. Moreover, yields of both lignin and lipid components showed a significant relationship with SOC increase after incubation. These findings showed that the larger the lipid and lignin content of SOM, the greater was the stability of SOC, thereby suggesting that OM hydrophobic components may have an essential role in controlling the processes of OC sequestration in paddy soils of South China.

  20. 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...

  1. 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.

  2. Marine Microbial Community Response to Inorganic and Organic Sediment Amendments in Laboratory Mesocosms

    DTIC Science & Technology

    2011-07-23

    degradation of organic contaminants. The impacts of sediment amendments for metal and organic remediation including apatite, organoclay (and apatite and... organoclay in geotextile mats), acetate, and chitin on environmental microbial communities in overlying water and sediment profiles are reported here...2005; Cho et al. 2009). Currently, promising sediment amendments include inorganic (e.g. activated carbon, apatite, organoclay , and geotextile mats

  3. Biochar as soil amendment to improve soil quality, crop yield, and carbon sequestration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar, a by-product of a thermochemical process called pyrolysis, which involves burning of any agricultural and animal waste (biomass) under high temperature and absence of oxygen. It is assumed that since biochar is very high in aromatic carbon, which persists in soil environment for very long ...

  4. Influence of carbon source amendment on effectiveness of anaerobic soil disinfestation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anaerobic soil disinfestation (ASD; also termed biological soil disinfestation or soil reductive sterilization) is a non-chemical soil disinfestation process which includes 1) soil incorporation of a labile carbon (C) source, 2) mulching with a polyethylene film to limit gas exchange, and 3) drip ir...

  5. Predicting long-term organic carbon dynamics in organically-amended soils using the CQESTR model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A process-based soil C model “CQESTR” was developed to simulate soil organic carbon (SOC) dynamics. The model has been validated successfully for North America, but needs to be tested in other geographic areas. We evaluated the predictive performance of CQESTR in a long-term (34-yr) SOC-depleted Eur...

  6. Carbon Mineralization in Two Ultisols Amended with Different Sources and Particle Sizes of Pyrolyzed Biochar

    EPA Science Inventory

    Biochar produced during pyrolysis has the potential to enhance soil fertility and reduce greenhouse gas emissions. The influence of biochar properties (e.g., particle size) on both short- and long-term carbon (C) mineralization of biochar remains unclear. There is minimal informa...

  7. Carbon mineralization in two ultisols amended with different sources and particle sizes of pyrolyzed biochar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar produced during pyrolysis has the potential to enhance soil fertility and reduce greenhouse gas emissions. The influence of biochar properties (e.g. particle size) on both short- and long-term carbon (C) mineralization of biochar remains unclear. There is minimal information on the potential...

  8. Review of the effects of biochar amendment on soil properties and carbon sequestration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar is part of a series of materials referred to as black carbons, since biochar is produced by a chemical and/or thermal transformation of the original biomass material in different conditions. The objective of this paper is to summarize the characteristics of biochar from different feedstocks ...

  9. 75 FR 20813 - Certain Magnesia Carbon Bricks from the People's Republic of China: Amended Preliminary...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-21

    ... various metals, metal alloys, and metal carbides). Certain magnesia carbon bricks that are the subject of... treatments, anti-slip treatments or metal casing) and regardless of whether or not anti-oxidants are present... Co., Ltd. 130.96 Ltd Liaoning Jiayi Metals & Minerals Co., Ltd.. Liaoning Jiayi Metals & Minerals...

  10. Greenhouse gas emission from soil amended with biochar made from hydrothermally carbonizing swine solids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar made from hydrothermally carbonizing swine solids was mixed with a 50/50 mixture of Norfolk Ap and E horizon at a rate of 20 g/kg. During the incubation period of 54 days, greenhouse gas (CO2 and N2O) emission fluxes were calculated by nonlinearly regressing time-series headspace gas concent...

  11. 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.

  12. Characteristics of biochars from crop residues: potential for carbon sequestration and soil amendment.

    PubMed

    Windeatt, Jayne H; Ross, Andrew B; Williams, Paul T; Forster, Piers M; Nahil, Mohamad A; Singh, Surjit

    2014-12-15

    Biochar has potential to sequester carbon in soils and simultaneously improve soil quality and plant growth. More understanding of biochar variation is needed to optimise these potential benefits. Slow pyrolysis at 600 °C was undertaken to determine how yields and characteristics of biochars differ when produced from eight different agricultural residues. Biochar properties such as carbon content, surface area, pH, ultimate and proximate analysis, nutrient and metal content and the R50 recalcitrance index were determined. Significant variations seen in biochar characteristics were attributed to feedstock variation since pyrolysis conditions were constant. Biochar yields varied from 28% to 39%. Average carbon content was 51%. Ash content of both feedstocks and biochars were correlated with biochar carbon content. Macronutrients were concentrated during pyrolysis, but biochar macronutrient content was low in comparison to biochars produced from more nutrient rich feedstocks. Most biochars were slightly alkaline, ranging from pH 6.1 to pH 11.6. pH was correlated with biochar K content. Aromaticity was increased with pyrolysis, shown by a reduction in biochar H/C and O/C ratios relative to feedstock values. The R50 recalcitrance index showed biochars to be either class 2 or class 3. Biochar carbon sequestration potential was 21.3%-32.5%. The R50 recalcitrance index is influenced by the presence of alkali metals in the biochar which may lead to an under-estimation of biochar stability. The residues assessed here, at current global availability, could produce 373 Mt of biochar. This quantity of biochar has the potential to sequester 0.55 Pg CO2 yr(-1) in soils over long time periods.

  13. Simultaneous production of l-lactic acid with high optical activity and a soil amendment with food waste that demonstrates plant growth promoting activity.

    PubMed

    Kitpreechavanich, Vichien; Hayami, Arisa; Talek, Anfal; Chin, Clament Fui Seung; Tashiro, Yukihiro; Sakai, Kenji

    2016-07-01

    A unique method to produce highly optically-active l-lactic acid and soil amendments that promote plant growth from food waste was proposed. Three Bacillus strains Bacillus subtilis KBKU21, B. subtilis N3-9 and Bacillus coagulans T27, were used. Strain KBKU21 accumulated 36.9 g/L l-lactic acid with 95.7% optical activity and 98.2% l-lactic acid selectivity when fermented at 43°C for 84 h in a model kitchen refuse (MKR) medium. Residual precipitate fraction (anaerobically-fermented MKR (AFM) compost) analysis revealed 4.60%, 0.70% and 0.75% of nitrogen (as N), phosphorous (as P2O5), and potassium (as K2O), respectively. Additionally, the carbon to nitrogen ratio decreased from 13.3 to 10.6. AFM compost with KBKU21 promoted plant growth parameters, including leaf length, plant height and fresh weight of Brassica rapa (Komatsuna), than that by chemical fertilizers or commercial compost. The concept provides an incentive for the complete recycling of food waste, contributing towards a sustainable production system.

  14. 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.

  15. Influence of biochar amendments on marine sediment trace metal bioavailability

    NASA Astrophysics Data System (ADS)

    Gehrke, G. E.; Hsu-Kim, H.

    2014-12-01

    Biochar has become a desirable material for use in agricultural application to enhance soil quality and in-situ soil and sediment remediation to immobilize organic contaminants. We investigated the effects of biochar sediment amendments on the bioavailability of a suite of inorganic trace metals (Cr, Co, Ni, Cu, Zn, Pb) in contaminated sediments from multiple sites in Elizabeth River, VA. We incubated sediments in microcosms with a variety of water column redox and salinity conditions and compared sediments amended with two types of woody biochar to sediments amended with charcoal activated carbon and unamended sediments. We leached sediments in artificial gut fluid mimic of the benthic invertebrate Arenicola marina as a measure of bioavailability of the trace metals analyzed. In unamended anaerobic sediments, the gut fluid mimic leachable fraction of each trace metal is 1-4% of the total sediment concentration for each metal. Initial results indicate that in anaerobic microcosms, woody biochar sediment amendments (added to 5% dry wt) decrease the gut fluid mimic leachable fraction by 30-90% for all trace metals analyzed, and have comparable performance to charcoal activated carbon amendments. However, in microcosms without controlled redox conditions, woody biochar amendments increase the bioavailable fraction of Ni and Cu by up to 80%, while decreasing the bioavailable fraction of Co, Zn, and Pb by approximately 50%; charcoal activated carbon amendments decreased the bioavailability of all trace metals analyzed by approximately 20%. In microcosms without an overlying water column, biochar and activated carbon amendments had no significant effects on trace metal bioavailability. This research demonstrates that biochar can effectively decrease the bioavailability of trace metals in marine sediments, but its efficiency is metal-specific, and environmental conditions impact biochar performance.

  16. Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff

    USGS Publications Warehouse

    Babiarz, C.L.; Hurley, J.P.; Krabbenhoft, D.P.; Gilmour, C.; Branfireun, B.A.

    2003-01-01

    Results from pilot studies on colloidal phase transport of newly deposited mercury in lake water and overland runoff demonstrate that the combination of ultrafiltration, and stable isotope amendment techniques is a viable tool for the study of mercury partitioning to filterable carbon. Ultrafiltration mass balance calculations were generally excellent, averaging 97.3, 96.1 and 99.8% for dissolved organic carbon (DOC), total mercury (HgT), and methylmercury (MeHg), respectively. Sub nanogram per liter quantities of isotope were measurable, and the observed phase distribution from replicate ultrafiltration separations on lake water agreed within 20%. We believe the data presented here are the first published colloidal phase mercury data on lake water and overland runoff from uncontaminated sites. Initial results from pilot-scale lake amendment experiments indicate that the choice of matrix used to dissolve the isotope did not affect the initial phase distribution of the added mercury in the lake. In addition there was anecdotal evidence that native MeHg was either recently produced in the system, or at a minimum, that this 'old' MeHg partitions to the same subset of DOC that binds the amended mercury. Initial results from pilot-scale overland runoff experiments indicate that less than 20% of newly deposited mercury was transported in the filterable fraction (<0.7 ??m). There is some indication of colloidal phase enrichment of mercury in runoff compared to the phase distribution of organic carbon, but the mechanism of this enrichment is unclear. The phase distribution of newly deposited mercury can differ from that of organic carbon and native mercury, suggesting that the quality of the carbon (available ligands), not the quantity of carbon, regulates partitioning. Further characterization of DOC is needed to clarify the underlying mechanisms. ?? 2002 Elsevier Science B.V. All rights reserved.

  17. Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff.

    PubMed

    Babiarz, Christopher L; Hurley, James P; Krabbenhoft, David P; Gilmour, Cynthia; Branfireun, Brian A

    2003-03-20

    Results from pilot studies on colloidal phase transport of newly deposited mercury in lake water and overland runoff demonstrate that the combination of ultrafiltration, and stable isotope amendment techniques is a viable tool for the study of mercury partitioning to filterable carbon. Ultrafiltration mass balance calculations were generally excellent, averaging 97.3, 96.1 and 99.8% for dissolved organic carbon (DOC), total mercury (Hg(T)), and methylmercury (MeHg), respectively. Sub nanogram per liter quantities of isotope were measurable, and the observed phase distribution from replicate ultrafiltration separations on lake water agreed within 20%. We believe the data presented here are the first published colloidal phase mercury data on lake water and overland runoff from uncontaminated sites. Initial results from pilot-scale lake amendment experiments indicate that the choice of matrix used to dissolve the isotope did not affect the initial phase distribution of the added mercury in the lake. In addition there was anecdotal evidence that native MeHg was either recently produced in the system, or at a minimum, that this 'old' MeHg partitions to the same subset of DOC that binds the amended mercury. Initial results from pilot-scale overland runoff experiments indicate that less than 20% of newly deposited mercury was transported in the filterable fraction (<0.7 microm). There is some indication of colloidal phase enrichment of mercury in runoff compared to the phase distribution of organic carbon, but the mechanism of this enrichment is unclear. The phase distribution of newly deposited mercury can differ from that of organic carbon and native mercury, suggesting that the quality of the carbon (available ligands), not the quantity of carbon, regulates partitioning. Further characterization of DOC is needed to clarify the underlying mechanisms.

  18. 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.

  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. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Effects of Carbon in Flooded Paddy Soils: Implications for Microbial Activity and Arsenic Mobilization

    NASA Astrophysics Data System (ADS)

    Avancha, S.; Boye, K.

    2014-12-01

    In the Mekong delta in Cambodia, naturally occurring arsenic (originating from erosion in the Himalaya Mountains) in paddy soils is mobilized during the seasonal flooding. As a consequence, rice grown on the flooded soils may take up arsenic and expose people eating the rice to this carcinogenic substance. Microbial activity will enhance or decrease the mobilization of arsenic depending on their metabolic pathways. Among the microbes naturally residing in the soil are denitrifying bacteria, sulfate reducers, metal reducers (Fe, Mn), arsenic reducers, methanogens, and fermenters, whose activity varies based on the presence of oxygen. The purpose of the experiment was to assess how different amendments affect the microbial activity and the arsenic mobilization during the transition from aerobic to anaerobic metabolism after flooding of naturally contaminated Cambodian soil. In a batch experiment, we investigated how the relative metabolic rate of naturally occurring microbes could vary with different types of organic carbon. The experiment was designed to measure the effects of various sources of carbon (dried rice straw, charred rice straw, manure, and glucose) on the microbial activity and arsenic release in an arsenic-contaminated paddy soil from Cambodia under flooded conditions. All amendments were added based on the carbon content in order to add 0.036 g of carbon per vial. The soil was flooded with a 10mM TRIS buffer solution at pH 7.04 in airtight 25mL serum vials and kept at 25 °C. We prepared 14 replicates per treatment to sample both gas and solution. On each sampling point, the solution replicates were sampled destructively. The gas replicates continued on and were sampled for both gas and solution on the final day of the experiment. We measured pH, total arsenic, methane, carbon dioxide, and nitrous oxide at 8 hours, 1.5 days, 3.33 days, and 6.33 days from the start of the experiment.

  10. PCB bioavailability control in Lumbriculus variegatus through different modes of activated carbon addition to sediments

    SciTech Connect

    Xueli Sun; Upal Ghosh

    2007-07-01

    PCB bioavailability to a freshwater oligochaete (Lumbriculus variegatus) was studied using sediments from a PCB-impacted river that was treated with different modes of granular activated carbon (GAC) addition. The GAC used was bituminous coal-based type TOP. For sediment treated with 2.6% GAC and mixed for 2 min prior to L. variegatus addition, the reduction in total PCB biouptake was 70% for 75-300 {mu}m size carbon, and 92% for the 45-180 {mu}m size carbon. For the case where the GAC was placed as a thin layer on top of the sediments without mixing, the reduction in total PCB uptake was 70%. PCB biouptake kinetics study using treated and untreated sediment showed that the maximum PCB uptake in tissue was achieved at 28 days and decreased after that time. Although the absolute uptake of PCB changed over time, the percent reduction in total PCB uptake upon GAC amendment remained constant after the first few days. Our results indicated that PCB bioavailability was reduced upon the addition and little or no mixing of GAC into sediments. PCB aqueous equilibrium concentration and desorption rates were greatly reduced after GAC amendment, indicating reductions in the two primary mechanisms of PCB bioavailability in sediments: chemical activity and chemical accessibility. 29 refs., 5 figs., 1 tab.

  11. PCB bioavailability control in Lumbriculus variegatus through different modes of activated carbon addition to sediments.

    PubMed

    Sun, Xueli; Ghosh, Upal

    2007-07-01

    PCB bioavailability to a freshwater oligochaete (Lumbriculus variegatus) was studied using sediments from a PCB-impacted river that was treated with different modes of granular activated carbon (GAC) addition. For sedimenttreated with 2.6% GAC and mixed for 2 min prior to L. variegatus addition, the reduction in total PCB biouptake was 70% for 75-300 microm size carbon, and 92% for the 45-180 microm size carbon. For the case where the GAC was placed as a thin layer on top of the sediments without mixing, the reduction in total PCB uptake was 70%. PCB biouptake kinetics study using treated and untreated sediment showed that the maximum PCB uptake in tissue was achieved at 28 days and decreased after that time. Although the absolute uptake of PCB changed over time, the percent reduction in total PCB uptake upon GAC amendment remained constant after the first few days. Our results indicated that PCB bioavailability was reduced upon the addition and little or no mixing of GAC into sediments. PCB aqueous equilibrium concentration and desorption rates were greatly reduced after GAC amendment, indicating reductions in the two primary mechanisms of PCB bioavailability in sediments: chemical activity and chemical accessibility.

  12. 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.

  13. 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.

  14. 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.

  15. Long-term impacts of manure amendments on carbon and greenhouse gas dynamics of rangelands.

    PubMed

    Owen, Justine J; Parton, William J; Silver, Whendee L

    2015-12-01

    Livestock manure is applied to rangelands as an organic fertilizer to stimulate forage production, but the long-term impacts of this practice on soil carbon (C) and greenhouse gas (GHG) dynamics are poorly known. We collected soil samples from manured and nonmanured fields on commercial dairies and found that manure amendments increased soil C stocks by 19.0 ± 7.3 Mg C ha(-1) and N stocks by 1.94 ± 0.63 Mg N ha(-1) compared to nonmanured fields (0-20 cm depth). Long-term historical (1700-present) and future (present-2100) impacts of management on soil C and N dynamics, net primary productivity (NPP), and GHG emissions were modeled with DayCent. Modeled total soil C and N stocks increased with the onset of dairying. Nitrous oxide (N2 O) emissions also increased by ~2 kg N2 O-N ha(-1)  yr(-1) . These emissions were proportional to total N additions and offset 75-100% of soil C sequestration. All fields were small net methane (CH4 ) sinks, averaging -4.7 ± 1.2 kg CH4 -C ha(-1)  yr(-1) . Overall, manured fields were net GHG sinks between 1954 and 2011 (-0.74 ± 0.73 Mg CO2 e ha(-1)  yr(-1) , CO2 e are carbon dioxide equivalents), whereas nonmanured fields varied around zero. Future soil C pools stabilized 40-60 years faster in manured fields than nonmanured fields, at which point manured fields were significantly larger sources than nonmanured fields (1.45 ± 0.52 Mg CO2 e ha(-1)  yr(-1) and 0.51 ± 0.60 Mg CO2 e ha(-1)  yr(-1) , respectively). Modeling also revealed a large background loss of soil C from the passive soil pool associated with the shift from perennial to annual grasses, equivalent to 29.4 ± 1.47 Tg CO2 e in California between 1820 and 2011. Manure applications increased NPP and soil C storage, but plant community changes and GHG emissions decreased, and eventually eliminated, the net climate benefit of this practice.

  16. 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.

  17. Comparing the desorption and biodegradation of low concentrations of phenanthrene sorbed to activated carbon, biochar and compost.

    PubMed

    Marchal, Geoffrey; Smith, Kilian E C; Rein, Arno; Winding, Anne; Trapp, Stefan; Karlson, Ulrich G

    2013-02-01

    Carbonaceous soil amendments are applied to contaminated soils and sediments to strongly sorb hydrophobic organic contaminants (HOCs) and reduce their freely dissolved concentrations. This limits biouptake and toxicity, but also biodegradation. To investigate whether HOCs sorbed to such amendments can be degraded at all, the desorption and biodegradation of low concentrations of (14)C-labelled phenanthrene (≤5 μg L(-1)) freshly sorbed to suspensions of the pure soil amendments activated carbon (AC), biochar (charcoal) and compost were compared. Firstly, the maximum abiotic desorption of phenanthrene from soil amendment suspensions in water, minimal salts medium (MSM) or tryptic soy broth (TSB) into a dominating silicone sink were measured. Highest fractions remained sorbed to AC (84±2.3%, 87±4.1%, and 53±1.2% for water, MSM and TSB, respectively), followed by charcoal (35±2.2%, 32±1.7%, and 12±0.3%, respectively) and compost (1.3±0.21%, similar for all media). Secondly, the mineralization of phenanthrene sorbed to AC, charcoal and compost by Sphingomonas sp. 10-1 (DSM 12247) was determined. In contrast to the amounts desorbed, phenanthrene mineralization was similar for all the soil amendments at about 56±11% of the initially applied radioactivity. Furthermore, HPLC analyses showed only minor amounts (<5%) of residual phenanthrene remaining in the suspensions, indicating almost complete biodegradation. Fitting the data to a coupled desorption and biodegradation model revealed that desorption did not limit biodegradation for any of the amendments, and that degradation could proceed due to the high numbers of bacteria and/or the production of biosurfactants or biofilms. Therefore, reduced desorption of phenanthrene from AC or charcoal did not inhibit its biodegradation, which implies that under the experimental conditions these amendments can reduce freely dissolved concentration without hindering biodegradation. In contrast, phenanthrene sorbed to compost

  18. 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.

  19. 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...

  20. 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

  1. 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.

  2. 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

  3. Amended Silicated for Mercury Control

    SciTech Connect

    James Butz; Thomas Broderick; Craig Turchi

    2006-12-31

    Amended Silicates{trademark}, a powdered, noncarbon mercury-control sorbent, was tested at Duke Energy's Miami Fort Station, Unit 6 during the first quarter of 2006. Unit 6 is a 175-MW boiler with a cold-side electrostatic precipitator (ESP). The plant burns run-of-the-river eastern bituminous coal with typical ash contents ranging from 8-15% and sulfur contents from 1.6-2.6% on an as-received basis. The performance of the Amended Silicates sorbent was compared with that for powdered activated carbon (PAC). The trial began with a period of baseline monitoring during which no sorbent was injected. Sampling during this and subsequent periods indicated mercury capture by the native fly ash was less than 10%. After the baseline period, Amended Silicates sorbent was injected at several different ratios, followed by a 30-day trial at a fixed injection ratio of 5-6 lb/MMACF. After this period, PAC was injected to provide a comparison. Approximately 40% mercury control was achieved for both the Amended Silicates sorbent and PAC at injection ratios of 5-6 lbs/MMACF. Higher injection ratios did not achieve significantly increased removal. Similar removal efficiencies have been reported for PAC injection trials at other plants with cold-side ESPs, most notably for plants using medium to high sulfur coal. Sorbent injection did not detrimentally impact plant operations and testing confirmed that the use of Amended Silicates sorbent does not degrade fly ash quality (unlike PAC). The cost for mercury control using either PAC or Amended Silicates sorbent was estimated to be equivalent if fly ash sales are not a consideration. However, if the plant did sell fly ash, the effective cost for mercury control could more than double if those sales were no longer possible, due to lost by-product sales and additional cost for waste disposal. Accordingly, the use of Amended Silicates sorbent could reduce the overall cost of mercury control by 50% or more versus PAC for locations where fly

  4. Effects of poultry manure amendment on soil phosphorus fractions, phosphatase activity, and phosphorus uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poultry manure (PM) contains a large amount of P, and adding this manure to soil can impact the availability of native soil P to plants. To investigate the effects of PM on soil P availability, we grew ryegrass (Lolium perenne) in greenhouse pots amended with poultry manure. Biomass was harvested at...

  5. 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.

  6. Carbon nanotube amendment for treating dichlorodiphenyltrichloroethane and hexachlorocyclohexane remaining in Dong-ting Lake sediment - An implication for in-situ remediation.

    PubMed

    Zhang, Jian; Gong, Ji-Lai; Zeng, Guang-Ming; Yang, Hu-Cheng; Zhang, Peng

    2017-02-01

    Organochlorine pesticides (OCPs) were largely sprayed on the floodplain soils before the project of Returning Farmland to Lake in China, which caused contamination of sediment in Dong-ting Lake with dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) and posed threats to human health and other organisms. In this study, single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) at different concentrations of 0.058, 0.145 and 0.29wt% were used to manage residual DDTs and HCHs in Dong-ting Lake sediment. The efficacy was assessed by DDTs and HCHs deriving from the aqueous equilibrium experiment and uptake in semipermeable membrane devices (SPMDs). Desorption experiment and the quiescent flux experiment were conducted as well. The results showed that DDTs and HCHs were released from sediment. The p, p'-DDT was desorbed less readily than its metabolites and similarly α-HCH was desorbed less easily than other HCH isomers from sediment. Carbon nanotubes had great effects on treating DDTs and HCHs. The effectiveness of carbon nanotube amendment was dependent on type, dose and sediment-sorbent contact time In addition, carbon nanotubes being sprinkled on the surface of sediment as a cap and being injected into sediment as a mixture were considered as two effective ways to prevent DDTs and HCHs being released from sediment. Carbon nanotubes can be potentially useful as sorbents in in-situ remediation.

  7. 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

  8. 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.

  9. 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

  10. 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...

  11. 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.

  12. Carbon dioxide emissions from semi-arid soils amended with biochar alone or combined with mineral and organic fertilizers.

    PubMed

    Fernández, José M; Nieto, M Aurora; López-de-Sá, Esther G; Gascó, Gabriel; Méndez, Ana; Plaza, César

    2014-06-01

    Semi-arid soils cover a significant area of Earth's land surface and typically contain large amounts of inorganic C. Determining the effects of biochar additions on CO2 emissions from semi-arid soils is therefore essential for evaluating the potential of biochar as a climate change mitigation strategy. Here, we measured the CO2 that evolved from semi-arid calcareous soils amended with biochar at rates of 0 and 20tha(-1) in a full factorial combination with three different fertilizers (mineral fertilizer, municipal solid waste compost, and sewage sludge) applied at four rates (equivalent to 0, 75, 150, and 225kg potentially available Nha(-1)) during 182 days of aerobic incubation. A double exponential model, which describes cumulative CO2 emissions from two active soil C compartments with different turnover rates (one relatively stable and the other more labile), was found to fit very well all the experimental datasets. In general, the organic fertilizers increased the size and decomposition rate of the stable and labile soil C pools. In contrast, biochar addition had no effects on any of the double exponential model parameters and did not interact with the effects ascribed to the type and rate of fertilizer. After 182 days of incubation, soil organic and microbial biomass C contents tended to increase with increasing the application rates of organic fertilizer, especially of compost, whereas increasing the rate of mineral fertilizer tended to suppress microbial biomass. Biochar was found to increase both organic and inorganic C contents in soil and not to interact with the effects of type and rate of fertilizer on C fractions. As a whole, our results suggest that the use of biochar as enhancer of semi-arid soils, either alone or combined with mineral and organic fertilizers, is unlikely to increase abiotic and biotic soil CO2 emissions.

  13. 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.

  14. 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.

  15. 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...

  16. 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%.

  17. 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.

  18. Utilizing thin-film solid-phase extraction to assess the effect of organic carbon amendments on the bioavailability of DDT and dieldrin to earthworms

    USGS Publications Warehouse

    Andrade, Natasha A.; Centofanti, Tiziana; McConnell, Laura L.; Hapeman, Cathleen J.; Torrents, Alba; Anh, Nguyen; Beyer, W. Nelson; Chaney, Rufus L.; Novak, Jeffrey M.; Anderson, Marya O.; Cantrell, Keri B.

    2014-01-01

    Improved approaches are needed to assess bioavailability of hydrophobic organic compounds in contaminated soils. Performance of thin-film solid-phase extraction (TF-SPE) using vials coated with ethylene vinyl acetate was compared to earthworm bioassay (Lumbricus terrestris). A DDT and dieldrin contaminated soil was amended with four organic carbon materials to assess the change in bioavailability. Addition of organic carbon significantly lowered bioavailability for all compounds except for 4,4′-DDT. Equilibrium concentrations of compounds in the polymer were correlated with uptake by earthworms after 48d exposure (R2 = 0.97; p 40yr of aging. Results show that TF-SPE can be useful in examining potential risks associated with contaminated soils and to test effectiveness of remediation efforts.

  19. 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.

  20. Soil organic carbon dynamics and its response to organic amendments under long-term fertilization in intensive rice systems in subtropical China

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Wang, X.; Xu, M.

    2010-12-01

    Paddy soil makes a major rice contribution to the global food supply, but only little is known about the soil organic carbon (SOC) dynamic and its relationship with management practices. This paper presents a study of four long-term experiment sites in subtropical China, which have had a double-rice system since 1980’s with various fertilization treatments. The main fertilization treatments are non-fertilization (Control), mineral nitrogen-phosphorus-potassium combination (NPK), and mineral NPK combined with organic amendments (e.g., livestock’s manure, green manure and straw). There are two types of treatments for the combined treatments: (1) the same rate (S-N) of mineral N fertilizer application, and (2) the same amount of total N (i.e., the sum of mineral N and organic-N) application with the reduced rate (R-N) of mineral N fertilizer application. Our study indicates that all fertilization treatments significantly increase above-ground carbon biomass and SOC. Compared with the NPK treatment, the S-N treatment showed significant effect on carbon biomass whereas the R-N treatment showed no effects on carbon biomass. The soil carbon sequestration rates at the four sites were 0.08-0.17 t ha-1 yr-1 for the NPK treatment and 0.17-0.82 t ha-1 yr-1 for the S-N and R-N combined treatments. Our analyses show that annual carbon sequestration responds positively, but non-linearly to annual carbon input at all sites, suggesting that these paddy fields may be getting close to carbon saturation.

  1. Apatite and Chitin Amendments Promote Microbial Activity and Augment Metal Removal in Marine Sediments

    DTIC Science & Technology

    2013-07-01

    geotextile mats, apatite, organoclay , and chitin. Inorganic amend- ments help to immobilize several toxic metals such as lead, zinc, and cadmium by...to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data...needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Influence of carbonization methods on the aromaticity of pyrogenic dissolved organic carbon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dissolved organic carbon (DOC) components of soil amendments such as biochar will influence the fundamental soil chemistry including the metal speciation, nutrient availability, and microbial activity. Quantitative correlation is necessary between (i) pyrogenic DOC components of varying aromaticity...

  7. Estimating potential risks to terrestrial invertebrates and plants exposed to bisphenol A in soil amended with activated sludge biosolids.

    PubMed

    Staples, Charles; Friederich, Urs; Hall, Tilghman; Klecka, Gary; Mihaich, Ellen; Ortego, Lisa; Caspers, Norbert; Hentges, Steven

    2010-02-01

    Bisphenol A (BPA) is a high production volume substance primarily used to produce polycarbonate plastic and epoxy resins. During manufacture and use, BPA may enter wastewater treatment plants. During treatment, BPA may become adsorbed to activated sludge biosolids, which may expose soil organisms to BPA if added to soil as an amendment. To evaluate potential risks to organisms that make up the base of the terrestrial food web (i.e., invertebrates and plants) in accordance with international regulatory practice, toxicity tests were conducted with potworms (Enchytraeids) and springtails (Collembolans) in artificial soil, and six plant types using natural soil. No-observed-effect concentrations (NOEC) for potworms and springtails were equal to or greater than 100 and equal to or greater than 500 mg/kg (dry wt), respectively. The lowest organic matter-normalized NOEC among all tests (dry shoot weight of tomatoes) was 37 mg/kg-dry weight. Dividing by an assessment factor of 10, a predicted-no-effect concentration in soil (PNEC(soil)) of 3.7 mg/kg-dry weight was calculated. Following international regulatory guidance, BPA concentrations in soil hypothetically amended with biosolids were calculated using published BPA concentrations in biosolids. The upper 95th percentile BPA biosolids concentration in North America is 14.2 mg/kg-dry weight, and in Europe is 95 mg/kg-dry weight. Based on recommended biosolids application rates, predicted BPA concentrations in soil (PEC(soil)) would be 0.021 mg/kg-dry weight for North America and 0.14 mg/kg-dry weight for Europe. Hazard quotients (ratio of PEC(soil) and PNEC(soil)) for BPA were all equal to or less than 0.04. This indicates that risks to representative invertebrates and plants at the base of the terrestrial food web are low if exposed to BPA in soil amended with activated sludge biosolids.

  8. 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.

  9. 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.

  10. 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.

  11. The influence of redox chemistry and pH on chemically active forms of arsenic in sewage sludge-amended soil

    SciTech Connect

    Carbonell-Barrachina, A.; Jugsujinda, A.; DeLaune, R.D.; Patrick, W.H. Jr.; Burlo, F.; Sirisukhodom, S.; Anurakpongsatorn, P.

    1999-07-01

    Chemical fractionation procedures were used to quantify the effect of the sediment redox and pH conditions on the adsorption and solubility of arsenic (As) in municipal sewage sludge and sewage sludge-amended soil. Sludge and sludge-amended soil were incubated in microcosms in which Eh-pH conditions were controlled. Samples were sequentially extracted to determine As in various chemical forms (water soluble, exchangeable, bound to carbonates, bound to iron (Fe) and manganese (Mn) oxides, bound to insoluble organics and sulfides) and the chemically inactive fraction (mineral residues). In both sewage sludge and sludge-amended soil, As chemistry was governed by large molecular humic matter and sulfides and Fe and Mn-oxides. Solubility of As remained low and constant under both aerobic and anaerobic conditions in sludge-amended soil. After dissolution of Fe and Mn-oxides, As{sup 5+} was released into sludge solution, reduced to As{sup 3+} and likely precipitated as sulfide. Therefore, an organic amendment rich in sulfur compounds, such as sewage sludge, would drastically reduce the potential risks derived from As pollution under highly anoxic conditions by precipitation of this toxic metalloid as insoluble and immobile sulfides.

  12. 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

  13. 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.

  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. 78 FR 25701 - Certain Hot-Rolled Carbon Steel Flat Products From India: Notice of Second Amended Final Results...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-02

    ... International Trade Administration Certain Hot-Rolled Carbon Steel Flat Products From India: Notice of Second...) administrative review of certain hot-rolled carbon steel flat products from India for the 2007 review period (the..., 2013 (January 2013 remand results). \\2\\ See Certain Hot-Rolled Carbon Steel Flat Products from...

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

    SciTech Connect

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

    1995-11-01

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

  17. 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.

  18. Annual Report to the President and the Congress on Federal Activities Related to the Administration of the Rehabilitation Act of 1973, as Amended. Fiscal Year 1981. Executive Summary.

    ERIC Educational Resources Information Center

    Rehabilitation Services Administration (ED), Washington, DC.

    The fiscal year 1981 annual report of the Rehabilitation Services Administration's activities under the Rehabilitation Act of 1973, as amended, is presented; program operations, program development activities, functions of the National Institute of Handicapped Research, and other provisions of the Act, are described. Program operations include:…

  19. 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.

  20. 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

  1. Biochar, activated carbon, and carbon nanotubes have different effects on fate of 14C-catechol and microbial community in soil

    PubMed Central

    Shan, Jun; Ji, Rong; Yu, Yongjie; Xie, Zubin; Yan, Xiaoyuan

    2015-01-01

    This study investigated the effects of biochar, activated carbon (AC)-, and single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) in various concentrations (0, 0.2, 20, and 2,000 mg/kg dry soil) on the fate of 14C-catechol and microbial community in soil. The results showed that biochar had no effect on the mineralization of 14C-catechol, whereas AC at all amendment rates and SWCNTs at 2,000 mg/kg significantly reduced mineralization. Particularly, MWCNTs at 0.2 mg/kg significantly stimulated mineralization compared with the control soil. The inhibitory effects of AC and SWCNTs on the mineralization were attributed to the inhibited soil microbial activities and the shifts in microbial communities, as suggested by the reduced microbial biomass C and the separated phylogenetic distance. In contrast, the stimulatory effects of MWCNTs on the mineralization were attributed to the selective stimulation of specific catechol-degraders by MWCNTs at 0.2 mg/kg. Only MWCNTs amendments and AC at 2,000 mg/kg significantly changed the distribution of 14C residues within the fractions of humic substances. Our findings suggest biochar, AC, SWCNTs and MWCNTs have different effects on the fate of 14C-catechol and microbial community in soil. PMID:26515132

  2. Biochar, activated carbon, and carbon nanotubes have different effects on fate of 14C-catechol and microbial community in soil

    NASA Astrophysics Data System (ADS)

    Shan, Jun; Ji, Rong; Yu, Yongjie; Xie, Zubin; Yan, Xiaoyuan

    2015-10-01

    This study investigated the effects of biochar, activated carbon (AC)-, and single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) in various concentrations (0, 0.2, 20, and 2,000 mg/kg dry soil) on the fate of 14C-catechol and microbial community in soil. The results showed that biochar had no effect on the mineralization of 14C-catechol, whereas AC at all amendment rates and SWCNTs at 2,000 mg/kg significantly reduced mineralization. Particularly, MWCNTs at 0.2 mg/kg significantly stimulated mineralization compared with the control soil. The inhibitory effects of AC and SWCNTs on the mineralization were attributed to the inhibited soil microbial activities and the shifts in microbial communities, as suggested by the reduced microbial biomass C and the separated phylogenetic distance. In contrast, the stimulatory effects of MWCNTs on the mineralization were attributed to the selective stimulation of specific catechol-degraders by MWCNTs at 0.2 mg/kg. Only MWCNTs amendments and AC at 2,000 mg/kg significantly changed the distribution of 14C residues within the fractions of humic substances. Our findings suggest biochar, AC, SWCNTs and MWCNTs have different effects on the fate of 14C-catechol and microbial community in soil.

  3. Biochar, activated carbon, and carbon nanotubes have different effects on fate of (14)C-catechol and microbial community in soil.

    PubMed

    Shan, Jun; Ji, Rong; Yu, Yongjie; Xie, Zubin; Yan, Xiaoyuan

    2015-10-30

    This study investigated the effects of biochar, activated carbon (AC)-, and single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) in various concentrations (0, 0.2, 20, and 2,000 mg/kg dry soil) on the fate of (14)C-catechol and microbial community in soil. The results showed that biochar had no effect on the mineralization of (14)C-catechol, whereas AC at all amendment rates and SWCNTs at 2,000 mg/kg significantly reduced mineralization. Particularly, MWCNTs at 0.2 mg/kg significantly stimulated mineralization compared with the control soil. The inhibitory effects of AC and SWCNTs on the mineralization were attributed to the inhibited soil microbial activities and the shifts in microbial communities, as suggested by the reduced microbial biomass C and the separated phylogenetic distance. In contrast, the stimulatory effects of MWCNTs on the mineralization were attributed to the selective stimulation of specific catechol-degraders by MWCNTs at 0.2 mg/kg. Only MWCNTs amendments and AC at 2,000 mg/kg significantly changed the distribution of (14)C residues within the fractions of humic substances. Our findings suggest biochar, AC, SWCNTs and MWCNTs have different effects on the fate of (14)C-catechol and microbial community in soil.

  4. 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.

  5. 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.

  6. 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.

  7. Long-term changes in forest carbon under temperature and nitrogen amendments in a temperate northern hardwood forest.

    PubMed

    Savage, Kathleen E; Parton, William J; Davidson, Eric A; Trumbore, Susan E; Frey, Serita D

    2013-08-01

    Currently, forests in the northeastern United States are net sinks of atmospheric carbon. Under future climate change scenarios, the combined effects of climate change and nitrogen deposition on soil decomposition, aboveground processes, and the forest carbon balance remain unclear. We applied carbon stock, flux, and isotope data from field studies at the Harvard forest, Massachusetts, to the ForCent model, which integrates above- and belowground processes. The model was able to represent decadal-scale measurements in soil C stocks, mean residence times, fluxes, and responses to a warming and N addition experiment. The calibrated model then simulated the longer term impacts of warming and N deposition on the distribution of forest carbon stocks. For simulation to 2030, soil warming resulted in a loss of soil organic matter (SOM), decreased allocation to belowground biomass, and gain of aboveground carbon, primarily in large wood, with an overall small gain in total system carbon. Simulated nitrogen addition resulted in a small increase in belowground carbon pools, but a large increase in aboveground large wood pools, resulting in a substantial increase in total system carbon. Combined warming and nitrogen addition simulations showed a net gain in total system carbon, predominately in the aboveground carbon pools, but offset somewhat by losses in SOM. Hence, the impact of continuation of anthropogenic N deposition on the hardwood forests of the northeastern United States may exceed the impact of warming in terms of total ecosystem carbon stocks. However, it should be cautioned that these simulations do not include some climate-related processes, different responses from changing tree species composition. Despite uncertainties, this effort is among the first to use decadal-scale observations of soil carbon dynamics and results of multifactor manipulations to calibrate a model that can project integrated aboveground and belowground responses to nitrogen and climate

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Effects of inorganic and organic amendment on soil chemical properties, enzyme activities, microbial community and soil quality in yellow clayey soil.

    PubMed

    Liu, Zhanjun; Rong, Qinlei; Zhou, Wei; Liang, Guoqing

    2017-01-01

    Understanding the effects of external organic and inorganic components on soil fertility and quality is essential for improving low-yielding soils. We conducted a field study over two consecutive rice growing seasons to investigate the effect of applying chemical fertilizer (NPK), NPK plus green manure (NPKG), NPK plus pig manure (NPKM), and NPK plus straw (NPKS) on the soil nutrient status, enzyme activities involved in C, N, P, and S cycling, microbial community and rice yields of yellow clayey soil. Results showed that the fertilized treatments significantly improved rice yields over the first three experimental seasons. Compared with the NPK treatment, organic amendments produced more favorable effects on soil productivity. Notably, the NPKM treatment exhibited the highest levels of nutrient availability, microbial biomass carbon (MBC), activities of most enzymes and the microbial community. This resulted in the highest soil quality index (SQI) and rice yield, indicating better soil fertility and quality. Significant differences in enzyme activities and the microbial community were observed among the treatments, and redundancy analysis showed that MBC and available N were the key determinants affecting the soil enzyme activities and microbial community. The SQI score of the non-fertilized control (0.72) was comparable to that of the NPK (0.77), NPKG (0.81) and NPKS (0.79) treatments but significantly lower compared with NPKM (0.85). The significant correlation between rice yield and SQI suggests that SQI can be a useful to quantify soil quality changes caused by different agricultural management practices. The results indicate that application of NPK plus pig manure is the preferred option to enhance SOC accumulation, improve soil fertility and quality, and increase rice yield in yellow clayey soil.

  13. Effects of inorganic and organic amendment on soil chemical properties, enzyme activities, microbial community and soil quality in yellow clayey soil

    PubMed Central

    Liu, Zhanjun; Rong, Qinlei; Zhou, Wei; Liang, Guoqing

    2017-01-01

    Understanding the effects of external organic and inorganic components on soil fertility and quality is essential for improving low-yielding soils. We conducted a field study over two consecutive rice growing seasons to investigate the effect of applying chemical fertilizer (NPK), NPK plus green manure (NPKG), NPK plus pig manure (NPKM), and NPK plus straw (NPKS) on the soil nutrient status, enzyme activities involved in C, N, P, and S cycling, microbial community and rice yields of yellow clayey soil. Results showed that the fertilized treatments significantly improved rice yields over the first three experimental seasons. Compared with the NPK treatment, organic amendments produced more favorable effects on soil productivity. Notably, the NPKM treatment exhibited the highest levels of nutrient availability, microbial biomass carbon (MBC), activities of most enzymes and the microbial community. This resulted in the highest soil quality index (SQI) and rice yield, indicating better soil fertility and quality. Significant differences in enzyme activities and the microbial community were observed among the treatments, and redundancy analysis showed that MBC and available N were the key determinants affecting the soil enzyme activities and microbial community. The SQI score of the non-fertilized control (0.72) was comparable to that of the NPK (0.77), NPKG (0.81) and NPKS (0.79) treatments but significantly lower compared with NPKM (0.85). The significant correlation between rice yield and SQI suggests that SQI can be a useful to quantify soil quality changes caused by different agricultural management practices. The results indicate that application of NPK plus pig manure is the preferred option to enhance SOC accumulation, improve soil fertility and quality, and increase rice yield in yellow clayey soil. PMID:28263999

  14. 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.

  15. Managing compost stability and amendment to soil to enhance soil heating during soil solarization.

    PubMed

    Simmons, Christopher W; Guo, Hongyun; Claypool, Joshua T; Marshall, Megan N; Perano, Kristen M; Stapleton, James J; Vandergheynst, Jean S

    2013-05-01

    Soil solarization is a method of soil heating used to eradicate plant pathogens and weeds that involves passive solar heating of moist soil mulched (covered) with clear plastic tarp. Various types of organic matter may be incorporated into soil prior to solarization to increase biocidal activity of the treatment process. Microbial activity associated with the decomposition of soil organic matter may increase temperatures during solarization, potentially enhancing solarization efficacy. However, the level of organic matter decomposition (stability) necessary for increasing soil temperature is not well characterized, nor is it known if various amendments render the soil phytotoxic to crops following solarization. Laboratory studies and a field trial were performed to determine heat generation in soil amended with compost during solarization. Respiration was measured in amended soil samples prior to and following solarization as a function of soil depth. Additionally, phytotoxicity was estimated through measurement of germination and early growth of lettuce seedlings in greenhouse assays. Amendment of soil with 10%(g/g) compost containing 16.9 mg CO2/gdry weight organic carbon resulted in soil temperatures that were 2-4 °C higher than soil alone. Approximately 85% of total organic carbon within the amended soil was exhausted during 22 days of solarization. There was no significant difference in residual respiration with soil depth down to 17.4 cm. Although freshly amended soil proved highly inhibitory to lettuce seed germination and seedling growth, phytotoxicity was not detected in solarized amended soil after 22 days of field solarization.

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

    NASA Astrophysics Data System (ADS)

    Sajad, Mehran; Kazemzad, Mahmood; Hosseinnia, Azarmidokht

    2014-04-01

    In the current work, activated carbon monoliths have been prepared by application of different phenolic hydrocarbons namely catechol and resorcinol as carbon precursors. For synthesis of carbon monolith, the precursors have been mixed with Genapol PF-10 as template and then polymerized in the presence of lysine as catalyst. Then the polymerized monolith carbonized in inert atmosphere at 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.

  17. KSCS FOR A PAH AND PCB ASSOCIATED WITH A MARINE SEDIMENT AMENDED WITH SEVERAL TYPES OF SOOT CARBON

    EPA Science Inventory

    Soot carbon (SC) originates from the combustion of fossil fuels and biomass and is found in sediments around the world. SC comprises up to 30% of organic carbon in sediment and is now commonly recognized as a phase which must be considered when predicting the environmental par...

  18. Effects of Amendment with Ferrihydrite and Gypsum on the Structure and Activity of Methanogenic Populations in Rice Field Soil

    PubMed Central

    Lueders, Tillmann; Friedrich, Michael W.

    2002-01-01

    Methane emission from paddy fields may be reduced by the addition of electron acceptors to stimulate microbial populations competitive to methanogens. We have studied the effects of ferrihydrite and gypsum (CaSO4 · 2H2O) amendment on methanogenesis and population dynamics of methanogens after flooding of Italian rice field soil slurries. Changes in methanogen community structure were followed by archaeal small subunit (SSU) ribosomal DNA (rDNA)- and rRNA-based terminal restriction fragment length polymorphism analysis and by quantitative SSU rRNA hybridization probing. Under ferrihydrite amendment, acetate was consumed efficiently (<60 μM) and a rapid but incomplete inhibition of methanogenesis occurred after 3 days. In contrast to unamended controls, the dynamics of Methanosarcina populations were largely suppressed as indicated by rDNA and rRNA analysis. However, the low acetate availability was still sufficient for activation of Methanosaeta spp., as indicated by a strong increase of SSU rRNA but not of relative rDNA frequencies. Unexpectedly, rRNA amounts of the novel rice cluster I (RC-I) methanogens increased significantly, while methanogenesis was low, which may be indicative of transient energy conservation coupled to Fe(III) reduction by these methanogens. Under gypsum addition, hydrogen was rapidly consumed to low levels (∼0.4 Pa), indicating the presence of a competitive population of hydrogenotrophic sulfate-reducing bacteria (SRB). This was paralleled by a suppressed activity of the hydrogenotrophic RC-I methanogens as indicated by the lowest SSU rRNA quantities detected in all experiments. Full inhibition of methanogenesis only became apparent when acetate was depleted to nonpermissive thresholds (<5 μM) after 10 days. Apparently, a competitive, acetotrophic population of SRB was not present initially, and hence, acetotrophic methanosarcinal populations were less suppressed than under ferrihydrite amendment. In conclusion, although methane

  19. 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.

  20. 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.

  1. Impact of activated carbon on the catabolism of (14)C-phenanthrene in soil.

    PubMed

    Oyelami, Ayodeji O; Ogbonnaya, Uchenna; Muotoh, Chitom; Semple, Kirk T

    2015-06-01

    Activated carbon amendment to contaminated soil has been proposed as an alternative remediation strategy to the management of persistent organic pollutant in soils and sediments. The impact of varying concentrations (0%, 0.01%, 0.1% and 1.0%) of different types of AC on the development of phenanthrene catabolism in soil was investigated. Mineralisation of (14)C-phenanthrene was measured using respirometric assays. The increase in concentration of CB4, AQ5000 or CP1 in soil led to an increase in the length of the lag phases. Statistical analyses showed that the addition of increasing concentrations of AC to the soil significantly reduced (P < 0.05) the extent of (14)C-phenanthrene mineralisation. For example, for CB4-, AQ5000- and CP1-amended soils, the overall extent of (14)C-phenanthrene mineralisation reduced from 43.1% to 3.28%, 36.9% to 0.81% and 39.6% to 0.96%, respectively, after 120 days incubation. This study shows that the properties of AC, such as surface area, pore volume and particle size, are important factors in controlling the kinetics of (14)C-phenanthrene mineralisation in soil.

  2. Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon.

    PubMed

    Lewis, Ariel S; Huntington, Thomas G; Marvin-DiPasquale, Mark C; Amirbahman, Aria

    2016-05-01

    Wetlands are hotspots for production of toxic methylmercury (MeHg) that can bioaccumulate in the food web. The objective of this study was to determine whether the application of zero-valent iron (ZVI) or granular activated carbon (GAC) to wetland sediment could reduce MeHg production and bioavailability to benthic organisms. Field mesocosms were installed in a wetland fringing Hodgdon Pond (Maine, USA), and ZVI and GAC were applied. Pore-water MeHg concentrations were lower in treated compared with untreated mesocosms; however, sediment MeHg, as well as total Hg (THg), concentrations were not significantly different between treated and untreated mesocosms, suggesting that smaller pore-water MeHg concentrations in treated sediment were likely due to adsorption to ZVI and GAC, rather than inhibition of MeHg production. In laboratory experiments with intact vegetated sediment clumps, amendments did not significantly change sediment THg and MeHg concentrations; however, the mean pore-water MeHg and MeHg:THg ratios were lower in the amended sediment than the control. In the laboratory microcosms, snails (Lymnaea stagnalis) accumulated less MeHg in sediment treated with ZVI or GAC. The study results suggest that both GAC and ZVI have potential for reducing MeHg bioaccumulation in wetland sediment.

  3. Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon

    USGS Publications Warehouse

    Lewis, Ariel S.; Huntington, Thomas G.; Marvin-DiPasquale, Mark C.; Amirbahman, Aria

    2016-01-01

    Wetlands are hotspots for production of toxic methylmercury (MeHg) that can bioaccumulate in the food web. The objective of this study was to determine whether the application of zero-valent iron (ZVI) or granular activated carbon (GAC) to wetland sediment could reduce MeHg production and bioavailability to benthic organisms. Field mesocosms were installed in a wetland fringing Hodgdon Pond (Maine, USA), and ZVI and GAC were applied. Pore-water MeHg concentrations were lower in treated compared with untreated mesocosms; however, sediment MeHg, as well as total Hg (THg), concentrations were not significantly different between treated and untreated mesocosms, suggesting that smaller pore-water MeHg concentrations in treated sediment were likely due to adsorption to ZVI and GAC, rather than inhibition of MeHg production. In laboratory experiments with intact vegetated sediment clumps, amendments did not significantly change sediment THg and MeHg concentrations; however, the mean pore-water MeHg and MeHg:THg ratios were lower in the amended sediment than the control. In the laboratory microcosms, snails (Lymnaea stagnalis) accumulated less MeHg in sediment treated with ZVI or GAC. The study results suggest that both GAC and ZVI have potential for reducing MeHg bioaccumulation in wetland sediment.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Nitrogen, carbon and phosphorus mineralization in soils from semi-arid highlands of central Mexico amended with tannery sludge.

    PubMed

    Barajas-Aceves, M; Dendooven, L

    2001-04-01

    Tannery sludge contains valuable nutrients and could be used as a fertilizer to pioneering vegetation in heavily eroded soils of the semi-arid highlands of central Mexico. Soil collected under and outside the canopy of mesquite (Prosopis laeviginata), huizache (Acacia tortuoso) and catclaw (Mimosa biuncifera), and cultivated with maize (Zea mays) and beans (Phaesolus vulgaris) was amended with 1.5 g tannery sludge kg-1 soil or 210 kg dry sludge ha-1 or left unamended. Amended and unamended soils were incubated aerobically for 70 days at 22 +/- 2 degrees C and CO2 production, available P, and inorganic N concentrations were monitored. The CO2 production rate, total C and P, available P, biomass C and P were larger under the canopy of the vegetation than outside of the canopy. The soils were depleted of N as more than 50 mg N kg-1 soil could not be accounted for in the first days of the incubation. Nitrification showed a lag, which lasted 28 days, and concentration of available P remained constant or increased slightly. Application of tannery sludge to soil increased CO2 production with 6.5 mg CO2 kg-1 soil d-1 and inorganic N with 30 mg N kg-1 soil after 70 days, but available P did not increase. Application of tannery sludge increased C and N mineralization and could thus provide valuable nutrients to a pioneer vegetation. Although no inhibitory effects on the biological functioning of the soil were found, further investigation into possible long-term environmental effects are necessary.

  11. 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.

  12. Utilizing thin-film solid-phase extraction to assess the effect of organic carbon amendments on the bioavailability of DDT and dieldrin to earthworms.

    PubMed

    Andrade, Natasha A; Centofanti, Tiziana; McConnell, Laura L; Hapeman, Cathleen J; Torrents, Alba; Nguyen, Anh; Beyer, W Nelson; Chaney, Rufus L; Novak, Jeffrey M; Anderson, Marya O; Cantrell, Keri B

    2014-02-01

    Improved approaches are needed to assess bioavailability of hydrophobic organic compounds in contaminated soils. Performance of thin-film solid-phase extraction (TF-SPE) using vials coated with ethylene vinyl acetate was compared to earthworm bioassay (Lumbricus terrestris). A DDT and dieldrin contaminated soil was amended with four organic carbon materials to assess the change in bioavailability. Addition of organic carbon significantly lowered bioavailability for all compounds except for 4,4'-DDT. Equilibrium concentrations of compounds in the polymer were correlated with uptake by earthworms after 48d exposure (R(2) = 0.97; p < 0.001), indicating TF-SPE provided an accurate uptake simulation. Bioavailability of residues in soil was compared with a spiked soil aged for 90d in laboratory. Dieldrin and DDX were respectively 18% and 11% less bioavailable in contaminated soil relative to spiked soil despite >40yr of aging. Results show that TF-SPE can be useful in examining potential risks associated with contaminated soils and to test effectiveness of remediation efforts.

  13. 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.

  14. 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

  15. Activated carbon fibers and engineered forms from renewable resources

    DOEpatents

    Baker, Frederick S.

    2010-06-01

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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. Contaminant immobilization and nutrient release by biochar soil amendment: roles of natural organic matter.

    PubMed

    Uchimiya, Minori; Lima, Isabel M; Klasson, K Thomas; Wartelle, Lynda H

    2010-08-01

    Contamination of soil interstitial waters by labile heavy metals such as Cu(II), Cd(II), and Ni(II) is of worldwide concern. Carbonaceous materials such as char and activated carbon have received considerable attention in recent years as soil amendment for both sequestering heavy metal contaminants and releasing essential nutrients like sulfur. Information is currently lacking in how aging impacts the integrity of biochars as soil amendment for both agricultural and environmental remediation purposes. Major contributors to biochar aging in soils are: sorption of environmental constituents, especially natural organic matter (NOM), and oxidation. To investigate the impact of NOM and organic fractions of chars, we employed broiler litter-derived chars and steam-activated carbons that underwent varying degrees of carbonization, in the presence and absence of NOM having known carboxyl contents. For aging by oxidation, we employed phosphoric acid activated carbons that underwent varying degrees of oxidation during activation. The results suggest that the organic fractions of biochars, and NOM having high carboxyl contents can mobilize Cu(II) retained by alkaline soil. Base treatment of broiler litter-derived char formed at low pyrolysis temperature (350 degrees C) improved the immobilization of all heavy metals investigated, and the extent of immobilization was similar to, or slightly greater than pecan shell-derived phosphoric acid activated carbons. Portions of total sulfur were released in soluble form in soil amended with broiler litter-derived carbons, but not pecan shell-derived phosphoric acid activated carbons.

  6. 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.

  7. 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

  8. In Situ Sediment Treatment Using Activated Carbon: A Demonstrated Sediment Cleanup Technology

    PubMed Central

    Patmont, Clayton R; Ghosh, Upal; LaRosa, Paul; Menzie, Charles A; Luthy, Richard G; Greenberg, Marc S; Cornelissen, Gerard; Eek, Espen; Collins, John; Hull, John; Hjartland, Tore; Glaza, Edward; Bleiler, John; Quadrini, James

    2015-01-01

    This paper reviews general approaches for applying activated carbon (AC) amendments as an in situ sediment treatment remedy. In situ sediment treatment involves targeted placement of amendments using installation options that fall into two general approaches: 1) directly applying a thin layer of amendments (which potentially incorporates weighting or binding materials) to surface sediment, with or without initial mixing; and 2) incorporating amendments into a premixed, blended cover material of clean sand or sediment, which is also applied to the sediment surface. Over the past decade, pilot- or full-scale field sediment treatment projects using AC—globally recognized as one of the most effective sorbents for organic contaminants—were completed or were underway at more than 25 field sites in the United States, Norway, and the Netherlands. Collectively, these field projects (along with numerous laboratory experiments) have demonstrated the efficacy of AC for in situ treatment in a range of contaminated sediment conditions. Results from experimental studies and field applications indicate that in situ sequestration and immobilization treatment of hydrophobic organic compounds using either installation approach can reduce porewater concentrations and biouptake significantly, often becoming more effective over time due to progressive mass transfer. Certain conditions, such as use in unstable sediment environments, should be taken into account to maximize AC effectiveness over long time periods. In situ treatment is generally less disruptive and less expensive than traditional sediment cleanup technologies such as dredging or isolation capping. Proper site-specific balancing of the potential benefits, risks, ecological effects, and costs of in situ treatment technologies (in this case, AC) relative to other sediment cleanup technologies is important to successful full-scale field application. Extensive experimental studies and field trials have shown that when

  9. Interactions between organic amendments and phosphate fertilizers modify phosphate sorption processes in an acid soil

    SciTech Connect

    Sckefe, C.R.; Patti, A.F.; Clune, T.S.; Jackson, W.R.

    2008-07-15

    To determine how organic amendments and phosphate fertilizers interact to modify P sorption processes, three phosphate fertilizers were applied to lignite- and compost-amended acid soil and incubated for either 3 or 26 days. The fertilizers applied were potassium dihydrogen phosphate, triple superphosphate, and diammonium phosphate (DAP). After 3 days of incubation, sorption of all three P sources was decreased in the lignite-amended treatments, whereas P sorption was increased in the compost-amended treatments. Increased incubation time (26 days) resulted in significantly decreased P sorption when DAP was added to lignite-amended treatments. Addition of triple superphosphate increased P sorption in lignite- and compost-amended treatments and decreased solution pH compared with DAP application. In addition to the effect of P source, differences in P sorption between the lignite- and compost-amended treatments were driven by differences in solution chemistry, predominantly solution pH and cation dynamics. Soil amendment and fertilizer addition also increased microbial activity in the incubation systems, as measured by carbon dioxide respiration. It is proposed that the combination of lignite and DAP may contribute to decreased P sorption in acid soils, with the positive effects likely caused by both chemical and biological processes, including the formation of soluble organic-metal complexes.

  10. 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.

  11. 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.

  12. 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 ...

  13. [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.

  14. Influence of soil properties on heavy metal sequestration by biochar amendment: 2. Copper desorption isotherms.

    PubMed

    Uchimiya, Minori; Klasson, K Thomas; Wartelle, Lynda H; Lima, Isabel M

    2011-03-01

    Contaminant desorption constrains the long-term effectiveness of remediation technologies, and is strongly influenced by dynamic non-equilibrium states of environmental and biological media. Information is currently lacking in the influence of biochar and activated carbon amendments on desorption of heavy metal contaminants from soil components. In this study, copper sorption-desorption isotherms were obtained for clay-rich, alkaline San Joaquin soil with significant heavy metal sorption capacity, and eroded, acidic Norfolk sandy loam soil having low capacity to retain copper. Acidic pecan shell-derived activated carbon and basic broiler litter biochar were employed in desorption experiments designed to address both leaching by rainfall and toxicity characteristics. For desorption in synthetic rain water, broiler litter biochar amendment diminished sorption-desorption hysteresis. In acetate buffer (pH 4.9), significant copper leaching was observed, unless acidic activated carbon (pH(pzc)=3.07) was present. Trends observed in soluble phosphorus and zinc concentrations for sorption and desorption equilibria suggested acid dissolution of particulate phases that can result in a concurrent release of copper and other sorbed elements. In contrast, sulfur and potassium became depleted as a result of supernatant replacements only when amended carbon (broiler litter biochar) or soil (San Joaquin) contained appreciable amounts. A positive correlation was observed between the equilibrium aluminum concentration and initial copper concentration in soils amended with acidic activated carbon but not basic biochar, suggesting the importance of cation exchange mechanism, while dissolution of aluminum oxides cannot be ruled out.

  15. Long-term rice cultivation stabilizes soil organic carbon and promotes soil microbial activity in a salt marsh derived soil chronosequence.

    PubMed

    Wang, Ping; Liu, Yalong; Li, Lianqing; Cheng, Kun; Zheng, Jufeng; Zhang, Xuhui; Zheng, Jinwei; Joseph, Stephen; Pan, Genxing

    2015-10-27

    Soil organic carbon (SOC) sequestration with enhanced stable carbon storage has been widely accepted as a very important ecosystem property. Yet, the link between carbon stability and bio-activity for ecosystem functioning with OC accumulation in field soils has not been characterized. We assessed the changes in microbial activity versus carbon stability along a paddy soil chronosequence shifting from salt marsh in East China. We used mean weight diameter, normalized enzyme activity (NEA) and carbon gain from straw amendment for addressing soil aggregation, microbial biochemical activity and potential C sequestration, respectively. In addition, a response ratio was employed to infer the changes in all analyzed parameters with prolonged rice cultivation. While stable carbon pools varied with total SOC accumulation, soil respiration and both bacterial and fungal diversity were relatively constant in the rice soils. Bacterial abundance and NEA were positively but highly correlated to total SOC accumulation, indicating an enhanced bio-activity with carbon stabilization. This could be linked to an enhancement of particulate organic carbon pool due to physical protection with enhanced soil aggregation in the rice soils under long-term rice cultivation. However, the mechanism underpinning these changes should be explored in future studies in rice soils where dynamic redox conditions exist.

  16. Long-term rice cultivation stabilizes soil organic carbon and promotes soil microbial activity in a salt marsh derived soil chronosequence

    PubMed Central

    Wang, Ping; Liu, Yalong; Li, Lianqing; Cheng, Kun; Zheng, Jufeng; Zhang, Xuhui; Zheng, Jinwei; Joseph, Stephen; Pan, Genxing

    2015-01-01

    Soil organic carbon (SOC) sequestration with enhanced stable carbon storage has been widely accepted as a very important ecosystem property. Yet, the link between carbon stability and bio-activity for ecosystem functioning with OC accumulation in field soils has not been characterized. We assessed the changes in microbial activity versus carbon stability along a paddy soil chronosequence shifting from salt marsh in East China. We used mean weight diameter, normalized enzyme activity (NEA) and carbon gain from straw amendment for addressing soil aggregation, microbial biochemical activity and potential C sequestration, respectively. In addition, a response ratio was employed to infer the changes in all analyzed parameters with prolonged rice cultivation. While stable carbon pools varied with total SOC accumulation, soil respiration and both bacterial and fungal diversity were relatively constant in the rice soils. Bacterial abundance and NEA were positively but highly correlated to total SOC accumulation, indicating an enhanced bio-activity with carbon stabilization. This could be linked to an enhancement of particulate organic carbon pool due to physical protection with enhanced soil aggregation in the rice soils under long-term rice cultivation. However, the mechanism underpinning these changes should be explored in future studies in rice soils where dynamic redox conditions exist. PMID:26503629

  17. Effects of temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon

    SciTech Connect

    Kan, E.; Huling, S.G.

    2009-03-01

    The effects of temperature and acidic pretreatment on Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC, derived from bituminous coal) were investigated. Limiting factors in MTBE removal in GAC include the heterogeneous distribution of amended Fe, and slow intraparticle diffusive transport of MTBE and hydrogen peroxide (H{sub 2}O{sub 2}) into the 'reactive zone'. Acid pretreatment of GAC before Fe amendment altered the surface chemistry of the GAC, lowered the pH point of zero charge, and resulted in greater penetration and more uniform distribution of Fe in GAC. This led to a condition where Fe, MTBE, and H{sub 2}O{sub 2} coexisted over a larger volume of the GAC contributing to greater MTBE oxidation and removal. H{sub 2}O{sub 2} reaction and MTBE removal in GAC increased with temperature. Modeling H{sub 2}O{sub 2} transport and reaction in GAC indicated that H{sub 2}O{sub 2} penetration was inversely proportional with temperature and tortuosity, and occurred over a larger fraction of the total volume of small GAC particles (0.3 mm diameter) relative to large particles (1.2 mm diameter). Acidic pretreatment of GAC, Fe-amendment, elevated reaction temperature, and use of small GAC particles are operational parameters that improve Fenton-driven oxidation of MTBE in GAC. 29 refs., 6 figs., 1 tab.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Bacterial Mobilization of Nutrients From Biochar-Amended Soils.

    PubMed

    Schmalenberger, A; Fox, A

    2016-01-01

    Soil amendments with biochar to improve soil fertility and increase soil carbon stocks have received some high-level attention. Physical and chemical analyses of amended soils and biochars from various feedstocks are reported, alongside some evaluations of plant growth promotion capabilities. Fewer studies investigated the soil microbiota and their potential to increase cycling and mobilization of nutrients in biochar-amended soils. This review is discussing the latest findings in the bacterial contribution to cycling and mobilizing nitrogen, phosphorus, and sulfur in biochar-amended soils and potential contributions to plant growth promotion. Depending on feedstock, pyrolysis, soil type, and plant cover, changes in the bacterial community structure were observed for a majority of the studies using amplicon sequencing or genetic fingerprinting methods. Prokaryotic nitrification largely depends on the availability of ammonium and can vary considerably under soil biochar amendment. However, denitrification to di-nitrogen and in particular, nitrous oxide reductase activity is commonly enhanced, resulting in reduced nitrous oxide emissions. Likewise, bacterial fixation of di-nitrogen appears to be regularly enhanced. A paucity of studies suggests that bacterial mobilization of phosphorus and sulfur is enhanced as well. However, most studies only tested for extracellular sulfatase and phosphatase activity. Further research is needed to reveal details of the bacterial nutrient mobilizing capabilities and this is in particular the case for the mobilization of phosphorus and sulfur.

  11. 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.

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

    PubMed

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

    2015-04-09

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

  13. 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.

  14. 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.

  15. [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.

  16. 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.

  17. Effects of long term irrigation with polluted water and sludge amendment on some soil enzyme activities

    SciTech Connect

    Topac, F.O.; Baskaya, H.S.; Alkan, U.; Katkat, A.V.

    2008-01-15

    The objective of this study was to determine the effects of wastewater sludge-fly ash mixtures on urease, dehydrogenase, alkaline phosphatase and beta-glucosidase activities in soils. In order to evaluate the probable effects of previous soil management practices (irrigation with polluted water) on soil enzymes, two different soil samples which were similar in physical properties, but different in irrigation practice were used. The application of wastewater sludges supplemented with varying doses of fly ash increased potential enzyme activities for a short period of time (3 months) in comparison to unamended soils. However, the activity levels generally showed a decreasing trend with increasing ash ratios indicating the inhibitory effect of fly ash. The urease and dehydrogenase activities were particularly lower in soils irrigated from a polluted stream, indicating the negative effects of the previous soil management on soil microbial activity.

  18. 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

  19. 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

  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. Influence of soil properties on heavy metal sequestration by biochar amendment: 1. Copper sorption isotherms and the release of cations.

    PubMed

    Uchimiya, Minori; Klasson, K Thomas; Wartelle, Lynda H; Lima, Isabel M

    2011-03-01

    The amendment of carbonaceous materials such as biochars and activated carbons is a promising in situ remediation strategy for both organic and inorganic contaminants in soils and sediments. Mechanistic understandings in sorption of heavy metals on amended soil are necessary for appropriate selection and application of carbonaceous materials for heavy metal sequestration in specific soil types. In this study, copper sorption isotherms were obtained for soils having distinct characteristics: clay-rich, alkaline San Joaquin soil with significant heavy metal sorption capacity, and eroded, acidic Norfolk sandy loam soil having low capacity to retain copper. The amendment of acidic pecan shell-derived activated carbon and basic broiler litter biochar lead to a greater enhancement of copper sorption in Norfolk soil than in San Joaquin soil. In Norfolk soil, the amendment of acidic activated carbon enhanced copper sorption primarily via cation exchange mechanism, i.e., release of proton, calcium, and aluminum, while acid dissolution of aluminum cannot be ruled out. For San Joaquin soil, enhanced copper retention by biochar amendment likely resulted from the following additional mechanisms: electrostatic interactions between copper and negatively charged soil and biochar surfaces, sorption on mineral (ash) components, complexation of copper by surface functional groups and delocalized π electrons of carbonaceous materials, and precipitation. Influence of biochar on the release of additional elements (e.g., Al, Ca) must be carefully considered when used as a soil amendment to sequester heavy metals.

  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. 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.

  4. 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...

  5. 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

  6. 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).

  7. Amendment application in a multi-contaminated mine soil: effects on soil enzymatic activities and ecotoxicological characteristics.

    PubMed

    Manzano, Rebeca; Esteban, Elvira; Peñalosa, Jesús M; Alvarenga, Paula

    2014-03-01

    Several amendments were tested on soils obtained from an arsenopyrite mine, further planted with Arrhenatherum elatius and Festuca curvifolia, in order to assess their ability to improve soil's ecotoxicological characteristics. The properties used to assess the effects were: soil enzymatic activities (dehydrogenase, β-glucosidase, acid phosphatase, urease, protease and cellulase), terrestrial bioassays (Eisenia fetida mortality and avoidance behaviour), and aquatic bioassays using a soil leachate (Daphnia magna immobilisation and Vibrio fischeri bioluminescence inhibition). The treatment with FeSO4 1 % w/w was able to reduce extractable As in soil, but increased the extractable Cu, Mn and Zn concentrations, as a consequence of the decrease in soil pH, in relation to the unamended soil, from 5.0 to 3.4, respectively. As a consequence, this treatment had a detrimental effect in some of the soil enzymatic activities (e.g. dehydrogenase, acid phosphatase, urease and cellulase), did not allow plant growth, induced E. fetida mortality in the highest concentration tested (100 % w/w), and its soil leachate was very toxic towards D. magna and V. fischeri. The combined application of FeSO4 1 % w/w with other treatments (e.g. CaCO3 1 % w/w and paper mill 1 % w/w) allowed a decrease in extractable As and metals, and a soil pH value closer to neutrality. As a consequence, dehydrogenase activity, plant growth and some of the bioassays identified those as better soil treatments to this type of multi-contaminated soil.

  8. Effects of conventional and no-tillage soil management and compost and sludge amendment on soil CO2 fluxes and microbial activities

    NASA Astrophysics Data System (ADS)

    Garcia-Gil, Juan Carlos; Haller, Isabel; Soler-Rovira, Pedro; Polo, Alfredo

    2010-05-01

    Soil management exerts a significant influence on the dynamic of soil organic matter, which is a key issue to enhance soil quality and its ecological functions, but also affects to greenhouse gas emissions and C sequestration processes. The objective of the present research was to determine the influence of soil management (conventional deep-tillage and no-tillage) and the application of two different organic amendment -thermally-dry sewage sludge (TSL) and municipal waste compost (MWC)- on soil CO2 fluxes and microbial activities in a long-term field experiment under semi-arid conditions. Both organic amendments were applied at a rate of 30 t ha-1 prior to sowing a barley crop. The experiment was conducted on an agricultural soil (Calcic Luvisol) from the experimental farm "La Higueruela" (Santa Olalla, Toledo). Unamended soils were used as control in both conventional and no-tillage management. During the course of the experiment, soil CO2 fluxes, microbial biomass C (MBC) and enzyme activities involved in the biogeochemical cycles of C, N and P were monitored during 12 months. The results obtained during the experiment for soil CO2 fluxes showed a great seasonal fluctuation due to semi-arid climate conditions. Overall, conventional deep-tillage soils exhibited higher CO2 fluxes, which was particularly larger during the first hours after deep-tillage was performed, and smaller MBC content and significantly lower dehydrogenase, beta-glucosidase, phosphatase, urease and BAA protease activities than no-tillage soils. Both MWC and TSL amendments provoked a significant increase of CO2 fluxes in both conventional and no-tillage soils, which was larger in TSL amended soils and particularly in no-tillage soils. The application of these organic amendments also enhanced MBC content and the overall enzyme activities in amended soils, which indicate a global revitalization of soil microbial metabolism in response to the fresh input of organic compounds that are energy

  9. 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.

  10. Contaminant Immobilization and Nutrient Release by Biochar Soil Amendment: Roles of Natural Organic Matter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of soil interstitial waters by labile heavy metals such as CuII, CdII, and NiII is of worldwide concern. Carbonaceous materials such as char and activated carbon have received considerable attention in recent years as soil amendment for both sequestering heavy metal contaminants and r...

  11. Influence of soil properties on heavy metal sequestration by biochar amendment: 2. copper desorption isotherms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contaminant desorption constrains the long-term effectiveness of remediation technologies, and is strongly influenced by dynamic non-equilibrium states of environmental and biological media. Information is currently lacking in the influence of biochar and activated carbon amendments on desorption of...

  12. 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

  13. 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.

  14. Effects of activated carbon ageing in three PCB contaminated sediments: Sorption efficiency and secondary effects on Lumbriculus variegatus.

    PubMed

    Nybom, Inna; Waissi-Leinonen, Greta; Mäenpää, Kimmo; Leppänen, Matti T; Kukkonen, Jussi V K; Werner, David; Akkanen, Jarkko

    2015-11-15

    The sorption efficiency and possible secondary effects of activated carbon (AC) (ø 63-200 μm) was studied with Lumbriculus variegatus in three PCB contaminated sediments applying long AC-sediment contact time (3 years). AC amendment efficiently reduced PCB bioavailability as determined with both, L. variegatus bioaccumulation test and passive samplers. However, dose related secondary effects of AC on egestion rate and biomass were observed (applied doses 0.25% and 2.5% sediment dry weight). The sorption capacity and secondary effects remained similar when the experiments were repeated after three years of AC-sediment contact time. Further, transmission electron microscopy (TEM) samples revealed morphological changes in the L. variegatus gut wall microvilli layer. Sediment properties affected both sorption efficiency and secondary effects, but 2.5% AC addition had significant effects regardless of the sediment. In, conclusion, AC is an efficient and stable sorbent to decrease the bioavailability of PCBs. However, sediment dwelling organisms, such as Oligochaete worms in this study, may be sensitive to the carbon amendments. The secondary effects and possible morphological changes in benthic organisms should not be overlooked as in many cases they form the basis of the aquatic food webs.

  15. 75 FR 31795 - Office of Biotechnology Activities; Recombinant DNA Research: Amended Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-04

    ... HUMAN SERVICES National Institutes of Health Office of Biotechnology Activities; Recombinant DNA... ] under Section III-A-1 of the NIH Guidelines for Research Involving Recombinant DNA Molecules (NIH... the NIH Recombinant DNA Advisory Committee has been deferred at the request of the...

  16. 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.

  17. 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.

  18. Bioprecipitation of Calcium Carbonate Crystals by Bacteria Isolated from Saline Environments Grown in Culture Media Amended with Seawater and Real Brine

    PubMed Central

    Silva-Castro, G. A.; Uad, I.; Gonzalez-Martinez, A.; Rivadeneyra, A.; Gonzalez-Lopez, J.; Rivadeneyra, M. A.

    2015-01-01

    The precipitation of calcium carbonate and calcium sulphate by isolated bacteria from seawater and real brine obtained in a desalination plant growth in culture media containing seawater and brine as mineral sources has been studied. However, only bioprecipitation was detected when the bacteria were grown in media with added organic matter. Biomineralization process started rapidly, crystal formation taking place in the beginning a few days after inoculation of media; roughly 90% of total cultivated bacteria showed. Six major colonies with carbonate precipitation capacity dominated bacterial community structure cultivated in heterotrophic platable bacteria medium. Taxonomic identification of these six strains through partial 16S rRNA gene sequences showed their affiliation with Gram-positive Bacillus and Virgibacillus genera. These strains were able to form calcium carbonate minerals, which precipitated as calcite and aragonite crystals and showed bacterial fingerprints or bacteria calcification. Also, carbonic anhydrase activity was observed in three of these isolated bacteria. The results of this research suggest that microbiota isolated from sea water and brine is capable of precipitation of carbonate biominerals, which can occur in situ with mediation of organic matter concentrations. Moreover, calcium carbonate precipitation ability of this microbiota could be of importance in bioremediation of CO2 and calcium in certain environments. PMID:26273646

  19. Bioprecipitation of Calcium Carbonate Crystals by Bacteria Isolated from Saline Environments Grown in Culture Media Amended with Seawater and Real Brine.

    PubMed

    Silva-Castro, G A; Uad, I; Gonzalez-Martinez, A; Rivadeneyra, A; Gonzalez-Lopez, J; Rivadeneyra, M A

    2015-01-01

    The precipitation of calcium carbonate and calcium sulphate by isolated bacteria from seawater and real brine obtained in a desalination plant growth in culture media containing seawater and brine as mineral sources has been studied. However, only bioprecipitation was detected when the bacteria were grown in media with added organic matter. Biomineralization process started rapidly, crystal formation taking place in the beginning a few days after inoculation of media; roughly 90% of total cultivated bacteria showed. Six major colonies with carbonate precipitation capacity dominated bacterial community structure cultivated in heterotrophic platable bacteria medium. Taxonomic identification of these six strains through partial 16S rRNA gene sequences showed their affiliation with Gram-positive Bacillus and Virgibacillus genera. These strains were able to form calcium carbonate minerals, which precipitated as calcite and aragonite crystals and showed bacterial fingerprints or bacteria calcification. Also, carbonic anhydrase activity was observed in three of these isolated bacteria. The results of this research suggest that microbiota isolated from sea water and brine is capable of precipitation of carbonate biominerals, which can occur in situ with mediation of organic matter concentrations. Moreover, calcium carbonate precipitation ability of this microbiota could be of importance in bioremediation of CO2 and calcium in certain environments.

  20. Controls and dynamics of biochar decay and soil microbial abundance, carbon use efficiency during long-term biochar-amended soil incubations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar addition to soil has been proposed as a management strategy to sequester a recalcitrant form of carbon (C). However, there is growing evidence that biochar can be degraded by soil microbes and modify their abundance, community composition and activity. Yet we lack an understanding of how mic...

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Comparative sorption and leaching study of the herbicides fluometuron and 4-chloro-2-methylphenoxyacetic acid (MCPA) in a soil amended with biochars and other sorbents.

    PubMed

    Cabrera, Alegria; Cox, Lucia; Spokas, Kurt A; Celis, Rafael; Hermosín, M Carmen; Cornejo, Juan; Koskinen, William C

    2011-12-14

    Biochar, the solid residual remaining after the thermochemical transformation of biomass for carbon sequestration, has been proposed to be used as a soil amendment, because of its agronomic benefits. The effect of amending soil with six biochars made from different feedstocks on the sorption and leaching of fluometuron and 4-chloro-2-methylphenoxyacetic acid (MCPA) was compared to the effect of other sorbents: an activated carbon, a Ca-rich Arizona montmorillonite modified with hexadecyltrimethylammonium organic cation (SA-HDTMA), and an agricultural organic residue from olive oil production (OOW). Soil was amended at 2% (w/w), and studies were performed following a batch equilibration procedure. Sorption of both herbicides increased in all amended soils, but decreased in soil amended with a biochar produced from macadamia nut shells made with fast pyrolysis. Lower leaching of the herbicides was observed in the soils amended with the biochars with higher surface areas BC5 and BC6 and the organoclay (OCl). Despite the increase in herbicide sorption in soils amended with two hardwood biochars (BC1 and BC3) and OOW, leaching of fluometuron and MCPA was enhanced with the addition of these amendments as compared to the unamended soil. The increased leaching is due to some amendments' soluble organic compounds, which compete or associate with herbicide molecules, enhancing their soil mobility. Thus, the results indicate that not all biochar amendments will increase sorption and decrease leaching of fluometuron and MCPA. Furthermore, the amount and composition of the organic carbon (OC) content of the amendment, especially the soluble part (DOC), can play an important role in the sorption and leaching of these herbicides.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Amendment in phosphorus levels moderate the chromium toxicity in Raphanus sativus L. as assayed by antioxidant enzymes activities.

    PubMed

    Sayantan, D; Shardendu

    2013-09-01

    Chromium (Z=24), a d-block element, is a potent carcinogen, whereas phosphorus is an essential and limiting nutrient for the plant growth and development. This study undertakes the role of phosphorus in moderating the chromium toxicity in Raphanus sativus L., as both of them compete with each other during the uptake process. Two-factor complete randomized experiment (5 chromium × 5 phosphorus concentrations) was conducted for twenty eight days in green house. The individuals of R. sativus were grown in pots supplied with all essential nutrients. The toxic effects of chromium and the moderation of toxicity due to phosphorus amendment were determined as accumulation of chromium, nitrogen, phosphorus in root tissues and their effects were also examined in the changes in biomass, chlorophyll and antioxidant enzyme levels. Cr and N accumulation were almost doubled at the highest concentration of Cr supply, without any P amendment, whereas at the highest P concentration (125 mM), the accumulation was reduced to almost half. A significant reduction in toxic effects of Cr was determined as there was three-fold increase in total chlorophyll and biomass at the highest P amendment. Antioxidant enzymes like superoxide dismutase, catalase, peroxidase and lipid peroxidation were analyzed at various levels of Cr each amended with five levels of P. It was observed that at highest level of P amendment, the reduction percentage in toxicity was 33, 44, 39 and 44, correspondingly. Conclusively, the phosphorus amendment moderates the toxicity caused by the supplied chromium in R. sativus. This finding can be utilized to develop a novel technology for the amelioration of chromium stressed fields.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. [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.

  12. 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.

  13. 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 ...

  14. 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.

  15. 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...

  16. 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...

  17. 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.

  18. 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.

  19. Characteristics of maize biochar with different pyrolysis temperatures and its effects on organic carbon, nitrogen and enzymatic activities after addition to fluvo-aquic soil.

    PubMed

    Wang, Xiubin; Zhou, Wei; Liang, Guoqing; Song, Dali; Zhang, Xiaoya

    2015-12-15

    In this study, the characteristics of maize biochar produced at different pyrolysis temperatures (300, 450 and 600°C) and its effects on organic carbon, nitrogen and enzymatic activities after addition to fluvo-aquic soil were investigated. As pyrolysis temperature increased, ash content, pH, electrical conductivity, surface area, pore volume and aromatic carbon content of biochar increased while yield, ratios of oxygen:carbon and hydrogen: carbon and alkyl carbon content decreased. During incubation, SOC, total N, and ammonium-N contents increased in all biochar-amended treatments compared with the urea treatment; however, soil nitrate-N content first increased and then decreased with increasing pyrolysis temperature of the applied biochar. Extracellular enzyme activities associated with carbon transformation first increased and then decreased with biochars pyrolyzed at 450 and 600°C. Protease activity markedly increased with increased pyrolysis temperatures, whereas pyrolysis temperature had limited effect on soil urease activity. The results indicated that the responses of extracellular enzymes to biochar were dependent on the pyrolysis temperature, the enzyme itself and incubation time as well.

  20. 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.

  1. 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.

  2. 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.

  3. Soil amendments yield persisting changes in the microbial communities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil microbial communities are sensitive to carbon amendments and largely control the decomposition and accumulation of soil organic matter. In this study, we evaluated whether the type of carbon amendment applied to wheat-cropped or fallow soil imparted lasting effects on the microbial community w...

  4. 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.

  5. 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

  6. Effects of soil amendment with different carbon sources and other factors on the bioremediation of an aged PAH-contaminated soil.

    PubMed

    Teng, Ying; Luo, Yongming; Ping, Lifeng; Zou, Dexun; Li, Zhengao; Christie, Peter

    2010-04-01

    Carbon supplementation, soil moisture and soil aeration are believed to enhance in situ bioremediation of PAH-contaminated soils by stimulating the growth of indigenous microorganisms. However, the effects of added carbon and nitrogen together with soil moisture and soil aeration on the dissipation of PAHs and on associated microbial counts have yet to be fully assessed. In this study the effects on bioremediation of carbon source, carbon-to-nitrogen ratio, soil moisture and aeration on an aged PAH-contaminated agricultural soil were studied in microcosms over a 90-day period. Additions of starch, glucose and sodium succinate increased soil bacterial and fungal counts and accelerated the dissipation of phenanthrene and benzo(a)pyrene in soil. Decreases in phenanthrene and benzo(a)pyrene concentrations were effective in soil supplemented with glucose and sodium succinate (both 0.2 g C kg(-1) dry soil) and starch (1.0 g C kg(-1) dry soil). The bioremediation effect at a C/N ratio of 10:1 was significantly higher (P < 0.05) than at a C/N of either 25:1 or 40:1. Soil microbial counts and PAH dissipation were lower in the submerged soil but soil aeration increased bacterial and fungal counts, enhanced indigenous microbial metabolic activities, and accelerated the natural degradation of phenanthrene and benzo(a)pyrene. The results suggest that optimizing carbon source, C/N ratio, soil moisture and aeration conditions may be a feasible remediation strategy in certain PAH contaminated soils with large active microbial populations.

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

    PubMed

    Clack, Herek L

    2012-07-03

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

  8. 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...

  9. 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].

  10. 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 ...

  11. Superoxide dismutase and total peroxidase activities in relation to drought recovery performance of mycorrhizal shrub seedlings grown in an amended semiarid soil.

    PubMed

    Roldán, Antonio; Díaz-Vivancos, Pedro; Hernández, José Antonio; Carrasco, Lucía; Caravaca, Fuensanta

    2008-05-05

    We studied the effect of inoculation with a mixture of three arbuscular mycorrhizal (AM) fungi (Glomus intraradices Schenck & Smith, Glomus deserticola (Trappe, Bloss. & Menge) and Glomus mosseae (Nicol & Gerd.) Gerd. & Trappe) and addition of a composted organic residue on plant growth, nutrient uptake, mycorrhizal colonisation and superoxide dismutase (SOD, EC 1.15.1.1) and total peroxidase (POX, EC 1.11.1.7) activities in shoots of Juniperus oxycedrus seedlings after well-watered, drought and recovery periods. The mycorrhizal inoculation and composted residue addition significantly increased the growth, foliar nutrients (N, P, K) and shoot water content of the plants, independent of the water regime. POX activity in control plants increased during drought (about 250% higher than under well-watered conditions) and returned to initial levels after re-watering. The seedlings inoculated with AM fungi showed the highest values of POX activity, followed by the plants grown in the amended soil, which varied little during the drought and recovery periods. Drought decreased the SOD activity in shoots of both J. oxycedrus seedlings inoculated with AM fungi and those grown with composted residue, but did not affect that of control plants. After re-watering, the SOD activity in mycorrhizal or residue-amended plants increased, showing values similar to control plants.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Environmental fate of the herbicide MCPA in agricultural soils amended with fresh and aged de-oiled two-phase olive mill waste.

    PubMed

    Peña, David; López-Piñeiro, Antonio; Albarrán, Ángel; Becerra, Daniel; Sánchez-Llerena, Javier

    2015-09-01

    Olive oil agrifood industry generates large amounts of waste whose recycling as organic amendment represents an alternative to their disposal. The impact of de-oiled two-phase olive mill waste (DW) on the fate of 4-chloro-2-methylphenoxyacetic acid (MCPA) in Mediterranean agricultural soils was evaluated. Furthermore, the effect of the transformation of organic matter from this waste under field conditions was assessed. Four Mediterranean agricultural soils were selected and amended in laboratory with fresh DW and field-aged DW (DW and ADW treatments, respectively). Adsorption capacity increased by factors between 1.18 and 3.59, for the DW-amended soils, and by factor of 4.93, for ADW-amended soil, with respect to unamended soils, when 5% amendment was applied. The DW amendment had inhibitory effect on dehydrogenase activity and slowed herbicide dissipation, whereas the opposite effect was observed in ADW treatments. In the field-amended soil, the amount of MCPA leached was significantly reduced from 56.9% for unamended soil to 15.9% at the 5% rate. However, leaching losses of MCPA increased in the laboratory-amended soils, because of their high water-soluble organic carbon values which could enhance MCPA mobility, especially in the acidic soils. Therefore, the application of DW as organic amendment in Mediterranean agricultural soils could be an important management strategy to reduce MCPA leaching, especially if the organic matter had been previously transformed by ageing processes.

  18. Effects of sewage sludge amendment on heavy metal accumulation and consequent responses of Beta vulgaris plants.

    PubMed

    Singh, R P; Agrawal, M

    2007-05-01

    Use of sewage sludge, a biological residue produced from sewage treatment processes in agriculture is an alternative disposal technique of waste. To study the usefulness of sewage sludge amendment for palak (Beta vulgaris var. Allgreen H-1), a leafy vegetable and consequent heavy metal contamination, a pot experiment was conducted by mixing sewage sludge at 20% and 40% (w/w) amendment ratios to the agricultural soil. Soil pH decreased whereas electrical conductance, organic carbon, total N, available P and exchangeable Na, K and Ca increased in soil amended with sewage sludge in comparison to unamended soil. Sewage sludge amendment led to significant increase in Pb, Cr, Cd, Cu, Zn and Ni concentrations of soil. Cd concentration in soil was found above the Indian permissible limit in soil at both the amendment ratios. The increased concentration of heavy metals in soil due to sewage sludge amendment led to increases in heavy metal uptake and shoot and root concentrations of Ni, Cd, Cu, Cr, Pb and Zn in plants as compared to those grown on unamended soil. Accumulation was more in roots than shoots for most of the heavy metals. Concentrations of Cd, Ni and Zn were more than the permissible limits of Indian standard in the edible portion of palak grown on different sewage sludge amendments ratios. Sewage sludge amendment in soil decreased root length, leaf area and root biomass of palak at both the amendment ratios, whereas shoot biomass and yield decreased significantly at 40% sludge amendment. Rate of photosynthesis, stomatal conductance and chlorophyll content decreased whereas lipid peroxidation, peroxidase activity and protein and proline contents, increased in plants grown in sewage sludge-amended soil as compared to those grown in unamended soil. The study clearly shows that increase in heavy metal concentration in foliage of plants grown in sewage sludge-amended soil caused unfavorable changes in physiological and biochemical characteristics of plants leading

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Biochar and activated carbon for enhanced trace organic contaminant retention in stormwater infiltration systems.

    PubMed

    Ulrich, Bridget A; Im, Eugenia A; Werner, David; Higgins, Christopher P

    2015-05-19

    To assess the effectiveness of biochar and activated carbon (AC) for enhanced trace organic contaminant (TOrC) retention in stormwater infiltration systems, an approach combining forward-prediction modeling and laboratory verification experiments was employed. Batch and column tests were conducted using representative TOrCs and synthetic stormwater. Based on batch screening tests, two commercially available biochars (BN-biochar and MCG-biochar) and an AC were investigated. The AC exhibited the strongest sorption, followed by MCG-biochar and BN-biochar. Langmuir isotherms provided better fits to equilibrium data than Freundlich isotherms. Due to superior sorption kinetics, 0.2 wt % MCG-biochar in saturated sand columns retained TOrCs more effectively than 1.0 wt % BN-biochar. A forward-prediction intraparticle diffusion model based on the Langmuir isotherm adequately predicted column results when calibrated using only batch parameters, as indicated by a Monte Carlo uncertainty analysis. Case study simulations estimated that an infiltration basin amended with F300-AC or MCG-biochar could obtain sorption-retarded breakthrough times for atrazine of 54 or 5.8 years, respectively, at a 1 in./h infiltration rate. These results indicate that biochars or ACs with superior sorption capacity and kinetics can enhance TOrC retention in infiltration systems, and performance under various conditions can be predicted using results from batch tests.

  5. The application of activated carbon enhanced lime for controlling acid gases, mercury, and dioxins from MWCs

    SciTech Connect

    Licata, A.; Babu, M.; Carlson, W.

    1996-12-31

    Environmental control agencies have sought to reduce Municipal Waste Combustor (MWC) emission rates by the implementation of new regulations. Examples of these regulations are Germany`s 17th Federal Regulation on Emission Protection; the Clean Air Act Amendments of 1990; EPA`s New Source Performance Standards (NSPS) and Emission Guidelines; and recent regulatory actions in Minnesota, New Jersey, and Florida to adopt Hg standards for MWCs. Sorbalit{reg_sign} is an activated carbon enhanced lime process that reduces MWC emissions and has been successfully demonstrated in Europe and the U.S. The process consists of two components: (1) a specially developed agent characterized by a high adsorption material capable of adsorbing toxic elements and acid gases, and (2) highly efficient air pollution control systems used by MWCs and various other types of combustion sources, which provide through agitation, a vortexing of the adsorbing agent mixture in a collection device, usually a fabric filter or ESP. This paper presents the theoretical design of the Sorbalit technology. Actual field test results illustrate applications that reduce the concerns related to mercury and dioxin emissions based on practical experience. The adsorbing agent is described in detail and results obtained in various types of air pollution control systems which are applicable to the U.S. are presented.

  6. Fenton-driven chemical regeneration of MTBE-spent granular activated carbon--a pilot study.

    PubMed

    Huling, Scott G; Kan, Eunsung; Caldwell, Caleb; Park, Saehan

    2012-02-29

    Three columns containing granular activated carbon (GAC) were placed on-line at a ground water pump and treat facility, saturated with methyl tert-butyl ether (MTBE), and regenerated with hydrogen peroxide (H2O2) under different chemical, physical, and operational conditions for 3 adsorption/oxidation cycles. Supplemental iron was immobilized in the GAC (≈6 g/kg) through the amendment of a ferrous iron solution. GAC regeneration occurred under ambient thermal conditions (21-27 °C), or enhanced thermal conditions (50 °C). Semi-continuous H2O2 loading resulted in saw tooth-like H2O2 concentrations, whereas continuous H2O2 loading resulted in sustained H2O2 levels and was more time efficient. Significant removal of MTBE was measured in all three columns using $(USD) 0.6 H2O2/lb GAC. Elevated temperature played a significant role in oxidative treatment, given the lower MTBE removal at ambient temperature (62-80%) relative to MTBE removal measured under thermally enhanced (78-95%), and thermally enhanced, acid pre-treated (92-97%) conditions. Greater MTBE removal was attributed to increased intraparticle MTBE desorption and diffusion and higher aqueous MTBE concentrations. No loss in the MTBE sorption capacity of the GAC was measured, and the reaction byproducts, tert-butyl alcohol and acetone were also degraded.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Cadmium accumulation retard activity of functional components of photo assimilation and growth of rice cultivars amended with vermicompost.

    PubMed

    Sebastian, Abin; Prasad, M N V

    2013-01-01

    Cadmium (Cd) uptake mediated alterations in functional components of photo assimilation during conversion of cow dung and poultry cast to vermicompost were studied in two Indian rice cultivars; MO 16 and MTU 7029. It was found that higher amount of Cd accumulate in plants grown in soil amended with vermicompost which in turn damaged functional components in photo assimilation. Enhancement of root growth was recognized as reason for Cd accumulation. Metabolic alterations noticed among plants were not taken place during application of raw materials used for vermicomposting such as cow dung and poultry cast amendment. Rice varieties accumulated Cd differentially where MTU 7029 accumulated more Cd compare to MO 16. It was also noticed that existence of negative correlation between zinc status of the plant and Cd accumulation.

  13. 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.

  14. Role of heteroatoms in activated carbon for removal of hexavalent chromium from wastewaters.

    PubMed

    Valix, M; Cheung, W H; Zhang, K

    2006-07-31

    Heteroatoms are elements including sulfur, nitrogen, oxygen and hydrogen which are found on the surface of activated carbons. This study investigated the surface modification arising from heteroatoms bonding to carbon aromatic rings within the activated carbon and their corresponding influence on the chromium adsorption process. Activated carbons were prepared from bagasse by physical. Chromium removal capacities of these activated carbons by adsorption and reduction were determined. Models which related the chromium adsorption and reduction capacities of activated carbons to carbon acidity and heteroatom site concentrations were established using multi-variable linear regression method. It was found the individual heteroatoms contributed separately to the basicity of the carbon which in turn determined the mechanism by which chromium was removed from solution. The surface areas of the carbons were also observed to influence the adsorption and reduction of chromium. These understandings provide the fundamental method of optimising chromium removal through suitable control of carbon surface chemistry and textural properties.

  15. Carbon sequestration efficiency of organic amendments in a long-term experiment on a vertisol in Huang-Huai-Hai Plain, China.

    PubMed

    Hua, Keke; Wang, Daozhong; Guo, Xisheng; Guo, Zibin

    2014-01-01

    Soil organic carbon (SOC) sequestration is important for improving soil fertility of cropland and for the mitigation of greenhouse gas emissions to the atmosphere. The efficiency of SOC sequestration depends on the quantity and quality of the organic matter, soil type, and climate. Little is known about the SOC sequestration efficiency of organic amendments in Vertisols. Thus, we conducted the research based on 29 years (1982-2011) of long-term fertilization experiment with a no fertilizer control and five fertilization regimes: CK (control, no fertilizer), NPK (mineral NPK fertilizers alone), NPK+1/2W (mineral NPK fertilizers combined with half the amount of wheat straw), NPK+W (mineral NPK fertilizers combined with full the amount of wheat straw), NPK+PM (mineral NPK fertilizers combined with pig manure) and NPK+CM (mineral NPK fertilizers combined cattle manure). Total mean annual C inputs were 0.45, 1.55, 2.66, 3.71, 4.68 and 6.56 ton/ha/yr for CK, NPK, NPKW1/2, NPKW, NPKPM and NPKCM, respectively. Mean SOC sequestration rate was 0.20 ton/ha/yr in the NPK treatment, and 0.39, 0.50, 0.51 and 0.97 ton/ha/yr in the NPKW1/2, NPKW, NPKPM, and NPKCM treatments, respectively. A linear relationship was observed between annual C input and SOC sequestration rate (SOCsequestration rate  = 0.16 Cinput -0.10, R = 0.95, P<0.01), suggesting a C sequestration efficiency of 16%. The Vertisol required an annual C input of 0.63 ton/ha/yr to maintain the initial SOC level. Moreover, the C sequestration efficiencies of wheat straw, pig manure and cattle manure were 17%, 11% and 17%, respectively. The results indicate that the Vertisol has a large potential to sequester SOC with a high efficiency, and applying cattle manure or wheat straw is a recommendable SOC sequestration practice in Vertisols.

  16. Activated carbon from flash pyrolysis of eucalyptus residue.

    PubMed

    Grima-Olmedo, C; Ramírez-Gómez, Á; Gómez-Limón, D; Clemente-Jul, C

    2016-09-01

    Forestry waste (eucalyptus sp) was converted into activated carbon by initial flash pyrolysis followed carbonization and CO2 activation. These residues were obtained from a pilot plant in Spain that produces biofuel, the biochar represented 10-15% in weight. It was observed that the highest activation was achieved at a temperature of 800 °C, the specific surface increased with time but, on the contrary, high loss of matter was observed. At 600 °C, although there was an important increase of the specific surface and the volume of micropores, at this temperature it was observed that the activation time was not an influential parameter. Finally, at 400 °C it was observed that the activation process was not very significant. Assessing the average pore diameter it was found that the lowest value corresponded to the activation temperature of 600 °C, which indicated the development of microporosity. When the activation temperature increases up to 800 °C the pore diameter increased developing mesoporosity.

  17. Synthesis and characterization of carbon nanotube from coconut shells activated carbon

    NASA Astrophysics Data System (ADS)

    Melati, A.; Hidayati, E.

    2016-03-01

    Carbon nanotubes (CNTs) have been explored in almost every single cancer treatment modality, including drug delivery, lymphatic targeted chemotherapy, photodynamic therapy, and gene therapy. They are considered as one of the most promising nanomaterial with the capability of both detecting the cancerous cells and delivering drugs or small therapeutic molecules to the cells. CNTs have unique physical and chemical properties such as high aspect ratio, ultralight weight, high mechanical strength, high electrical conductivity, and high thermal conductivity. Coconut Shell was researched as active carbon source on 500 - 600°C. These activated carbon was synthesized becomes carbon nanotube and have been proposed as a promising tool for detecting the expression of indicative biological molecules at early stage of cancer. Clinically, biomarkers cancer can be detected by CNT Biosensor. We are using pyrolysis methods combined with CVD process or Wet Chemical Process on 600°C. Our team has successfully obtained high purity, and aligned MWCNT (Multi Wall Nanotube) bundles on synthesis CNT based on coconut shells raw materials. CNTs can be used to cross the mammalian cell membrane by endocytosis or other mechanisms. SEM characterization of these materials have 179 nm bundles on phase 83° and their materials compound known by using FTIR characterization.

  18. 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.

  19. Activation and micropore structure determination of activated carbon-fiber composites

    SciTech Connect

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

    1997-09-05

    Rigid, high surface area activated carbon fiber composites have been produced with high permeabilities for environmental applications in gas and water purification. These novel monolithic adsorbents can be produced in single pieces to a given size and shape. The project involves a collaboration between the Oak Ridge National Laboratory (ORNL) and the Center for Applied Energy Research (CAER), University of Kentucky. The carbon fiber composites are produced at the ORNL and activated at the CAER using different methods, with the aims of producing a uniform degree of activation, and of closely controlling pore structure and adsorptive properties. The main focus of the present work has been to find a satisfactory means to uniformly activate large samples of carbon fiber composites and produce controlled pore structures. Several environmental applications have been explored for the activated carbon fiber composites. One of these was to evaluate the activated composites for the separation of CH{sub 4}-CO{sub 2} mixtures, and an apparatus was constructed specifically for this purpose. The composites were further evaluated in the cyclic recovery of volatile organics. The activated carbon fiber composites have also been tested for possible water treatment applications by studying the adsorption of sodium pentachlorophenolate, PCP.

  20. 75 FR 51754 - Certain Activated Carbon from the People's Republic of China: Notice of Partial Rescission of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-23

    ... Activated Carbon from the People's Republic of China: Notice of Partial Rescission of Antidumping Duty... of initiation of an administrative review of the antidumping duty order on certain activated carbon... Activated Carbon Plant; Datong Forward Activated Carbon Co., Ltd.; Datong Guanghua Activated Carbon Co.,...

  1. 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.

  2. Factors affecting the adsorption of chromium (VI) on activated carbon

    SciTech Connect

    Yavuz, R.; Orbak, I.; Karatepe, N.

    2006-09-15

    The aim of this investigation was to determine the adsorption behavior of chromium (VI) on two different activated carbon samples produced from Tuncbilek lignite. The effects of the initial chromium (VI) concentration (250-1000 mg/L), temperature (297-323 K) and pH (2.0-9.5) on adsorption were investigated systematically. The effectiveness of the parameters on chromium adsorption was found to be in the order of pH, the initial Cr(VI) concentration and the temperature. Increasing the pH from 2.0 to 9.5 caused a decrease in adsorption. However, the adsorption was increased by increasing the initial Cr(VI) concentration and temperature. The multilinear mathematical model was also developed to predict the Cr(VI) adsorption on activated carbon samples within the experimental conditions.

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

    PubMed

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

    2007-06-01

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

  4. Activated carbon treatment of municipal solid waste incineration flue gas.

    PubMed

    Lu, Shengyong; Ji, Ya; Buekens, Alfons; Ma, Zengyi; Jin, Yuqi; Li, Xiaodong; Yan, Jianhua

    2013-02-01

    Activated carbon injection is widely used to control dioxins and mercury emissions. Surprisingly little attention has been paid to its modelling. This paper proposes an expansion of the classical Everaerts-Baeyens model, introducing the expression of fraction of free adsorption sites, f (s), and asserting the significant contribution of fly ash to dioxins removal. Moreover, the model monitors dioxins partitioning between vapour and particulate phase, as well as removal efficiency for each congener separately. The effects of the principal parameters affecting adsorption are analysed according to a semi-analytical, semi-empirical model. These parameters include temperature, contact time during entrained-flow, characteristics (grain-size, pore structure, specific surface area) and dosage of activated carbon, lignite cokes or mineral adsorbent, fly ash characteristics and concentration, and type of incinerator plant.

  5. Enhancement and inhibition of microbial activity in hydrocarbon- contaminated arctic soils: Implications for nutrient-amended bioremediation

    USGS Publications Warehouse

    Braddock, J.F.; Ruth, M.L.; Catterall, P.H.; Walworth, J.L.; McCarthy, K.A.

    1997-01-01

    Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) end low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus. When nutrients were added to soil in the field at three levels of N:P (100:45, 200:90, and 300:135 mg/kg soil), the greatest stimulation in microbial activity occurred at the lowest, rather than the highest, level of nutrient addition. The total soil-water potentials ranged from -2 to -15 bar with increasing levels of fertilizer. Semivolatile hydrocarbon concentrations declined significantly only in the soils treated at the low fertilizer level. These results indicate that an understanding of nutrient effects at a specific site is essential for successful bioremediation.Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) and low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus

  6. Adsorption, desorption and bioregeneration in the treatment of 2-chlorophenol with activated carbon.

    PubMed

    Aktaş, Ozgür; Ceçen, Ferhan

    2007-03-22

    This study aims to clarify the effect of activated carbon type on the extent of adsorbability, desorbability, and bioregenerability in the treatment of 2-chlorophenol. Four different activated carbon types; thermally activated and chemically activated powdered carbons (PAC), and their granular countertypes (GAC) with similar physical characteristics were used. Thermally activated carbons adsorbed 2-chlorophenol much better than chemically activated ones. However, adsorption was more reversible in the case of chemically activated ones. The use of powdered and granular activated carbon countertypes resulted in comparable adsorption and desorption characteristics. For each activated carbon type, 2-chlorophenol exhibited higher adsorbability and lower desorbability than phenol. Biodegradation of 2-chlorophenol took place very slowly when it was used as the sole carbon source in acclimated and non-acclimated activated sludges. Bioregeneration occurred only via desorption due to an initial concentration gradient and no further desorption took place due to low biodegradability. Bioregeneration of activated carbon loaded with 2-chlorophenol was not a suitable option when 2-chlorophenol was the only carbon source. It is suggested to remove 2-chlorophenol via adsorption onto activated carbon rather than applying biological treatment. Also in such cases, the use of thermally activated carbons with higher adsorption and lower desorption capacities is recommended rather than chemically activated carbons.

  7. [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.

  8. 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.

  9. Restricted dynamics of molecular hydrogen confined in activated carbon nanopores

    SciTech Connect

    Contescu, Cristian I; Saha, Dipendu; Gallego, Nidia C; Mamontov, Eugene; Kolesnikov, Alexander I; Bhat, Vinay V

    2012-01-01

    Quasi-elastic neutron scattering was used for characterization of dynamics of molecular hydrogen confined in narrow nanopores of two activated carbon materials: PFAC (derived from polyfurfuryl alcohol) and UMC (ultramicroporous carbon). Fast, but incomplete ortho-para conversion was observed at 10 K, suggesting that scattering originates from the fraction of unconverted ortho isomer which is rotation-hindered because of confinement in nanopores. Hydrogen molecules entrapped in narrow nanopores (<7 ) were immobile below 22-25 K. Mobility increased rapidly with temperature above this threshold, which is 8 K higher than the melting point of bulk hydrogen. Diffusion obeyed fixed-jump length mechanism, indistinguishable between 2D and 3D processes. Thermal activation of diffusion was characterized between ~22 and 37 K, and structure-dependent differences were found between the two carbons. Activation energy of diffusion was higher than that of bulk solid hydrogen. Classical notions of liquid and solid do not longer apply for H2 confined in narrow nanopores.

  10. Effects of water stress, organic amendment and mycorrhizal inoculation on soil microbial community structure and activity during the establishment of two heavy metal-tolerant native plant species.

    PubMed

    Fernández, D A; Roldán, A; Azcón, R; Caravaca, F; Bååth, E

    2012-05-01

    Our aim was to examine the effect of water stress on plant growth and development of two native plant species (Tetraclinis articulata and Crithmum maritimum) and on microbial community composition and activity in the rhizosphere soil, following the addition of an organic amendment, namely sugar beet residue (SBR), and/or the inoculation with an arbuscular mycorrhizal (AM) fungus, namely Glomus mosseae, in a non-sterile heavy metal-polluted soil. The AM inoculation did not have any significant effect on plant growth of both species. In T. articulata, SBR increased shoot growth, foliar P, total phospholipid fatty acids (PLFA), fungi-related PLFA, AM fungi-related neutral lipid fatty acid, bacterial gram-positive/gram-negative PLFA ratio and the β-glucosidase and dehydrogenase activities. SBR and AM inoculation increased phosphatase activity in T. articulata plants grown under drought conditions. In both plants, there was a synergistic effect between AM inoculation and SBR on mycorrhizal colonisation under drought conditions. In C. maritimum, the increase produced by the SBR on total amounts of PLFA, bacterial gram-positive-related PLFA and bacterial gram-negative-related PLFA was considerably higher under drought conditions. Our results suggest that the effectiveness of the amendment with regard to stimulating microbial communities and plant growth was largely limited by drought, particularly for plant species with a low degree of mycorrhizal colonisation.

  11. The adsorption of pharmaceutically active compounds from aqueous solutions onto activated carbons.

    PubMed

    Rakić, Vesna; Rac, Vladislav; Krmar, Marija; Otman, Otman; Auroux, Aline

    2015-01-23

    In this study, the adsorption of pharmaceutically active compounds - salicylic acid, acetylsalicylic acid, atenolol and diclofenac-Na onto activated carbons has been studied. Three different commercial activated carbons, possessing ∼650, 900 or 1500m(2)g(-1) surface areas were used as solid adsorbents. These materials were fully characterized - their textural, surface features and points of zero charge have been determined. The adsorption was studied from aqueous solutions at 303K using batch adsorption experiments and titration microcalorimetry, which was employed in order to obtain the heats evolved as a result of adsorption. The maximal adsorption capacities of investigated solids for all target pharmaceuticals are in the range of 10(-4)molg(-1). The obtained maximal retention capacities are correlated with the textural properties of applied activated carbon. The roles of acid/base features of activated carbons and of molecular structures of adsorbate molecules have been discussed. The obtained results enabled to estimate the possibility to use the activated carbons in the removal of pharmaceuticals by adsorption.

  12. Organic amendments increase soil solution phosphate concentrations in an acid soil: A controlled environment study

    SciTech Connect

    Schefe, C.R.; Patti, A.F.; Clune, T.S.; Jackson, R.

    2008-04-15

    Soil acidification affects at least 4 million hectares of agricultural land in Victoria, Australia. Low soil pH can inhibit plant growth through increased soluble aluminum (Al) concentrations and decreased available phosphorus (P). The addition of organic amendments may increase P availability through competition for P binding sites, solubilization of poorly soluble P pools, and increased solution pH. The effect of two organic amendments (lignite and compost) on P solubility in an acid soil was determined through controlled environment (incubation) studies. Three days after the addition of lignite and compost, both treatments increased orthophosphate and total P measured in soil solution, with the compost treatments having the greatest positive effect. Increased incubation time (26 days) increased soil solution P concentrations in both untreated and amended soils, with the greatest effect seen in total P concentrations. The measured differences in solution P concentrations between the lignite- and compost-amended treatments were likely caused by differences in solution chemistry, predominantly solution pH and cation dynamics. Soil amendment with lignite or compost also increased microbial activity in the incubation systems, as measured by carbon dioxide respiration. Based on the results presented, it is proposed that the measured increase in soil solution P with amendment addition was likely caused by both chemical and biological processes, including biotic and abiotic P solubilization reactions, and the formation of soluble organic-metal complexes.

  13. The effects of activation temperature on physico-chemical characteristics of activated carbons derived from biomass wastes

    NASA Astrophysics Data System (ADS)

    Sutrisno, Bachrun; Hidayat, Arif

    2015-12-01

    This research focused on investigating in the effect of activation temperature on the physico-chemical properties of palm empty fruit bunch (PEFB) based activated carbon prepared by physical activation with carbon dioxide. The activation temperature was studied in the range of 400-800°C by keeping the activation temperature at 800°C for 120 min. It was found that the porous properties of activated carbon decreased with an increase in carbonization temperature. The activated carbons prepared at the highest activation temperature at 800°C and activation time of 120 min gave the activated carbon with the highest of BET surface area and pore volume of 938 m2/g and 0.4502 cm3/g, respectively

  14. Surface modification of activated carbons for CO 2 capture

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

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

  15. Addition of organic amendments contributes to C sequestration in trace element contaminated soils.

    NASA Astrophysics Data System (ADS)

    del Mar Montiel Rozas, María; Panettier, Marco; Madejón Rodríguez, Paula; Madejón Rodríguez, Engracia

    2015-04-01

    Nowadays, the study of global C cycle and the different natural sinks of C have become especially important in a climate change context. Fluxes of C have been modified by anthropogenic activities and, presently, the global objective is the decrease of net CO2 emission. For this purpose, many studies are being conducted at local level for evaluate different C sequestration strategies. These techniques must be, in addition to safe in the long term, environmentally friendly. Restoration of contaminated and degraded areas is considered as a strategy for SOC sequestration. Our study has been carried out in the Guadiamar Green Corridor (Seville, Spain) affected by the Aznalcóllar mining accident. This accident occurred 16 years ago, due to the failure of the tailing dam which contained 4-5 million m3 of toxic tailings (slurry and acid water).The affected soils had a layer of toxic sludge containing heavy metals as As, Cd, Cu, Pb and Zn. Restoration techniques began to be applied just after the accident, including the removal of the toxic sludge and a variable layer of topsoil (10-30 cm) from the surface. In a second phase, in a specific area (experimental area) of the Green Corridor the addition of organic amendments (Biosolid compost (BC) and Leonardite (LE), a low grade coal rich in humic acids) was carried out to increase pH, organic matter and fertility in a soil which lost its richest layer during the clean-up operation. In our experimental area, half of the plots (A) received amendments for four years (2002, 2003, 2006 and 2007) whereas the other half (B) received amendments only for two years (2002-2003). To compare, plots without amendments were also established. Net balance of C was carried out using values of Water Soluble Carbon (WSC) and Total Organic Carbon (TOC) for three years (2012, 2013 and 2015). To eliminate artificial changes carried out in the plots, amendment addition and withdrawal of biomass were taken into account to calculate balance of kg TOC

  16. 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.

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

    DOEpatents

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

    2011-07-19

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

  18. 40 CFR 60.1330 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... activated carbon? 60.1330 Section 60.1330 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Requirements § 60.1330 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, you must meet...

  19. 77 FR 12614 - Activated Carbon From China; Institution of a Five-Year Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-01

    ... COMMISSION Activated Carbon From China; Institution of a Five-Year Review AGENCY: United States International... whether revocation of the antidumping duty order on activated carbon from China would be likely to lead to..., the Department of Commerce issued an antidumping duty order on imports of activated carbon from...

  20. 40 CFR 60.1330 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... activated carbon? 60.1330 Section 60.1330 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Requirements § 60.1330 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, you must meet...

  1. 78 FR 26748 - Certain Activated Carbon From the People's Republic of China: Preliminary Results of Antidumping...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ... International Trade Administration Certain Activated Carbon From the People's Republic of China: Preliminary... duty order on certain activated carbon from the People's Republic of China (``PRC'') for the period of... The merchandise subject to the order is certain activated carbon.\\1\\ The products are...

  2. 40 CFR 62.15275 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... activated carbon? 62.15275 Section 62.15275 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... August 30, 1999 Other Monitoring Requirements § 62.15275 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans...

  3. 40 CFR 62.15275 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... activated carbon? 62.15275 Section 62.15275 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... August 30, 1999 Other Monitoring Requirements § 62.15275 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans...

  4. 40 CFR 62.15275 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... activated carbon? 62.15275 Section 62.15275 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... August 30, 1999 Other Monitoring Requirements § 62.15275 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans...

  5. 40 CFR 60.1330 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... activated carbon? 60.1330 Section 60.1330 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Requirements § 60.1330 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, you must meet...

  6. 40 CFR 60.1330 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... activated carbon? 60.1330 Section 60.1330 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Requirements § 60.1330 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, you must meet...

  7. 40 CFR 60.1330 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... activated carbon? 60.1330 Section 60.1330 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Requirements § 60.1330 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, you must meet...

  8. 40 CFR 62.15275 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... activated carbon? 62.15275 Section 62.15275 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... August 30, 1999 Other Monitoring Requirements § 62.15275 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans...

  9. 40 CFR 62.15275 - How do I monitor the injection rate of activated carbon?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... activated carbon? 62.15275 Section 62.15275 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... August 30, 1999 Other Monitoring Requirements § 62.15275 How do I monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans...

  10. 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.

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  13. Novel electro-fenton approach for regeneration of activated carbon.

    PubMed

    Bañuelos, Jennifer A; Rodríguez, Francisco J; Manríquez Rocha, Juan; Bustos, Erika; Rodríguez, Adrián; Cruz, Julio C; Arriaga, L G; Godínez, Luis A

    2013-07-16

    An electro-Fenton-based method was used to promote the regeneration of granular activated carbon (GAC) previously adsorbed with toluene. Electrochemical regeneration experiments were carried out using a standard laboratory electrochemical cell with carbon paste electrodes and a batch electrochemical reactor. For each system, a comparison was made using FeSO4 as a precursor salt in solution (homogeneous system) and an Fe-loaded ion-exchange resin (Purolite C-100, heterogeneous system), both in combination with electrogenerated H2O2 at the GAC cathode. In the two cases, high regeneration efficiencies were obtained in the presence of iron using appropriate conditions of applied potential and adsorption-polarization time. Consecutive loading and regeneration cycles of GAC were performed in the reactor without great loss of the adsorption properties, only reducing the regeneration efficiency by 1% per cycle during 10 cycles of treatment. Considering that, in the proposed resin-containing process, the use of Fe salts is avoided and that GAC cathodic polarization results in efficient cleaning and regeneration of the adsorbent material, this novel electro-Fenton approach could constitute an excellent alternative for regenerating activated carbon when compared to conventional methods.

  14. Enhanced adsorption of quaternary amine using modified activated carbon.

    PubMed

    Prahas, Devarly; Wang, M J; Ismadji, Suryadi; Liu, J C

    2014-01-01

    This study examined different methodologies to modify activated carbon (AC) for the removal of quaternary amine, tetramethylammonium hydroxide (TMAH), from water. Commercial carbon (WAC) was treated by nitric acid oxidation (NA-WAC), silica impregnation (SM-WAC0.5), and oxygen plasma (P10-WAC), and their characteristics and adsorption capacity were compared. The Langmuir model fitted the equilibrium adsorption data well under different pH. The maximum adsorption capacity of WAC was 27.77 mg/g, while those of NA-WAC, SM-WAC 0.5, and P10-WAC were 37.46, 32.83 and 29.03 mg/g, respectively. Nitric acid oxidation was the most effective method for enhancing the adsorption capacity of TMAH. Higher pH was favorable for TMAH adsorption. Desorption study revealed that NA-WAC had no considerable reduction in performance even after five cycles of regeneration by 0.1 N hydrochloric acid. It was proposed that electrostatic interaction was the main mechanism of TMAH adsorption on activated carbon.

  15. Removal of toxic chemicals from water with activated carbon

    USGS Publications Warehouse

    Dawson, V.K.; Marking, L.L.; Bills, T.D.

    1976-01-01

    Activated carbon was effective in removing fish toxicants and anesthetics from water solutions. Its capacity to adsorb 3-trifluoromethyl-4-nitrophenol (TFM), antimycin, NoxfishA? (5% rotenone), Dibrorms, juglone, MSa??222, and benzocaine ranged from 0.1 to 64 mg per gram of carbon. The adsorptive capacity (end point considered as a significant discharge) of activated carbon for removal of TFM was determined at column depths of 15, 30, and 60 cm; temperatures of 7, 12, 17, and 22 C; pH's of 6.5, 7.5, 8.5, and 9.5; and flow rates of 50, 78, 100, 200, and 940 ml/min. Adsorptive capacity increased when the contact time was increased by reducing the flow rate or increasing the column depth. The adsorptive capacity was not significantly influenced by temperature but was substantially higher at pH 6.5 than at the other pH's tested. A practical and efficient filter for purifying chemically treated water was developed.

  16. Influence of process parameters on the surface and chemical properties of activated carbon obtained from biochar by chemical activation.

    PubMed

    Angın, Dilek; Altintig, Esra; Köse, Tijen Ennil

    2013-11-01

    Activated carbons were produced from biochar obtained through pyrolysis of safflower seed press cake by chemical activation with zinc chloride. The influences of process variables such as the activation temperature and the impregnation ratio on textural and chemical-surface properties of the activated carbons were investigated. Also, the adsorptive properties of activated carbons were tested using methylene blue dye as the targeted adsorbate. The experimental data indicated that the adsorption isotherms are well described by the Langmuir equilibrium isotherm equation. The optimum conditions resulted in activated carbon with a monolayer adsorption capacity of 128.21 mg g(-1) and carbon content 76.29%, while the BET surface area and total pore volume corresponded to 801.5m(2)g(-1) and 0.393 cm(3)g(-1), respectively. This study demonstrated that high surface area activated carbons can be prepared from the chemical activation of biochar with zinc chloride as activating agents.

  17. Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In situ application of heavy metal stabilizing agents has in some cases increased the mobility of target metal contaminants. Mechanistic understandings are necessary to better predict (1) the dynamic short- and long-term response to soil amendments, and (2) the utility of biochars in nonremoval and...

  18. Sorption of priority pollutants to biochars and activated carbons for application to soil and sediment remediation

    NASA Astrophysics Data System (ADS)

    Beckingham, B.; Gomez-Eyles, J. L.; Kwon, S.; Riedel, G.; Gilmour, C.; Ghosh, U.

    2012-04-01

    acidic surface groups is demonstrated by the lower performance of unactivated biochars at high pH>9. However, at low concentrations AC performed better than the biochars made from marsh reed and hard wood. Thus, biochars as a class of sorbents are highly variable and their sorption properties depend on source material and pyrolysis treatment. Also, ACs contain some surface functionality and perhaps these higher energy sorption sites are not saturated at low Hg concentrations. For sites with mixed organic and inorganic contamination it is feasible that sustainable remediation may be most efficiently performed using biochar amendments that are tuned during production to optimize their surface area and functionality. High temperature oxidation to produce large surface areas has an energy and carbon cost, yet producing activated sorbents with renewable biomass residues improves sustainability. Biochars may be re-applied over time to account for lower sorptivity of organic pollutants which also augments the benefit to carbon sequestration.

  19. 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.

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

    PubMed

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

    2005-02-14

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

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

    PubMed

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

    2016-01-01

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

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

    SciTech Connect

    Jagtoyen, M.; Derbyshire, F.

    1999-04-23

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

  3. Effects of twice-ambient carbon dioxide and nitrogen amendment on biomass, nutrient contents and carbon costs of Norway spruce seedlings as influenced by mycorrhization with Piloderma croceum and Tomentellopsis submollis.

    PubMed

    Weigt, Rosemarie Barbara; Raidl, Stefan; Verma, Rita; Rodenkirchen, Hermann; Göttlein, Axel; Agerer, Reinhard

    2011-07-01

    Elevated tropospheric CO(2) concentrations may increase plant carbon fixation. In ectomycorrhizal trees, a considerable portion of the synthesized carbohydrates can be used to support the mutualistic fungal root partner which in turn can benefit the tree by increased nutrient supply. In this study, Norway spruce seedlings were inoculated with either Piloderma croceum (medium distance "fringe" exploration type) or Tomentellopsis submollis (medium distance "smooth" exploration type). We studied the impact of either species regarding fungal biomass production, seedling biomass, nutrient status and nutrient use efficiency in rhizotrons under ambient and twice-ambient CO(2) concentrations. A subset was amended with ammonium nitrate to prevent nitrogen imbalances expected under growth promotion by elevated CO(2). The two fungal species exhibited considerably different influences on growth, biomass allocation as well as nutrient uptake of spruce seedlings. P. croceum increased nutrient supply and promoted plant growth more strongly than T. submollis despite considerably higher carbon costs. In contrast, seedlings with T. submollis showed higher nutrient use efficiency, i.e. produced plant biomass per received unit of nutrient, particularly for P, K and Mg, thereby promoting shoot growth and reducing the root/shoot ratio. Under the given low soil nutrient availability, P. croceum proved to be a more favourable fungal partner for seedling development than T. submollis. Additionally, plant internal allocation of nutrients was differently influenced by the two ECM fungal species, particularly evident for P in shoots and for Ca in roots. Despite slightly increased ECM length and biomass production, neither of the two species had increased its capacity of nutrient uptake in proportion to the rise of CO(2). This lead to imbalances in nutritional status with reduced nutrient concentrations, particularly in seedlings with P. croceum. The beneficial effect of P. croceum thus

  4. Metal doped carbon nanoneedles and effect of carbon organization with activity for hydrogen evolution reaction (HER).

    PubMed

    Araujo, Rafael A; Rubira, Adley F; Asefa, Tewodros; Silva, Rafael

    2016-02-10

    Cellulose nanowhiskers (CNW) from cotton, was prepared by acid hydrolysis and purified using a size selection process to obtain homogeneous samples with average particle size of 270 nm and 85.5% crystallinity. Purified CNW was used as precursor to carbon nanoneedles (CNN) synthesis. The synthesis of CNN loaded with different metals dopants were carried out by a nanoreactor method and the obtained CNNs applied as electrocatalysts for hydrogen evolution reaction (HER). In the carbon nanoneedles synthesis, Ni, Cu, or Fe worked as graphitization catalyst and the metal were found present as dopants in the final material. The used metal appeared to have direct influence on the degree of organization of the particles and also in the surface density of polar groups. It was evaluated the influence of the graphitic organization on the general properties and nickel was found as the more appropriate metal since it leads to a more organized material and also to a high activity toward HER.

  5. Effects of biochar amendment on geotechnical properties of landfill cover soil.

    PubMed

    Reddy, Krishna R; Yaghoubi, Poupak; Yukselen-Aksoy, Yeliz

    2015-06-01

    Biochar is a carbon-rich product obtained when plant-based biomass is heated in a closed container with little or no available oxygen. Biochar-amended soil has the potential to serve as a landfill cover material that can oxidise methane emissions for two reasons: biochar amendment can increase the methane retention time and also enhance the biological activity that can promote the methanotrophic oxidation of methane. Hydraulic conductivity, compressibility and shear strength are the most important geotechnical properties that are required for the design of effective and stable landfill cover systems, but no studies have been reported on these properties for biochar-amended landfill cover soils. This article presents physicochemical and geotechnical properties of a biochar, a landfill cover soil and biochar-amended soils. Specifically, the effects of amending 5%, 10% and 20% biochar (of different particle sizes as produced, size-20 and size-40) to soil on its physicochemical properties, such as moisture content, organic content, specific gravity and pH, as well as geotechnical properties, such as hydraulic conductivity, compressibility and shear strength, were determined from laboratory testing. Soil or biochar samples were prepared by mixing them with 20% deionised water based on dry weight. Samples of soil amended with 5%, 10% and 20% biochar (w/w) as-is or of different select sizes, were also prepared at 20% initial moisture content. The results show that the hydraulic conductivity of the soil increases, compressibility of the soil decreases and shear strength of the soil increases with an increase in the biochar amendment, and with a decrease in biochar particle size. Overall, the study revealed that biochar-amended soils can possess excellent geotechnical properties to serve as stable landfill cover materials.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  7. Soil Microbial Activity Provides Insight to Carbon Cycling in Shrub Ecotones of Sub-Arctic Sweden

    NASA Astrophysics Data System (ADS)

    Marek, E.; Kashi, N. N.; Chen, J.; Hobbie, E. A.; Schwan, M. R.; Varner, R. K.

    2015-12-01

    Shrubs are expanding in Arctic and sub-Arctic regions due to rising atmospheric temperatures. Microbial activity increases as growing temperatures cause permafrost warming and subsequent thaw, leading to a greater resource of soil nutrients enabling shrub growth. Increased carbon inputs from shrubs is predicted to result in faster carbon turnover by microbial decomposition. Further understanding of microbial activity underneath shrubs could uncover how microbes and soil processes interact to promote shrub expansion and carbon cycling. To address how higher soil carbon input from shrubs influences decomposition, soil samples were taken across a heath, shrub, and forest ecotone gradient at two sites near Abikso, Sweden. Samples were analyzed for soluble carbon and nitrogen, microbial abundance, and microbial activity of chitinase, glucosidase, and phosphatase to reflect organic matter decomposition and availability of nitrogen, carbon, and phosphate respectively. Chitinase activity positively correlated with shrub cover, suggesting microbial demands for nitrogen increase with higher shrub cover. Glucosidase activity negatively correlated with shrub cover and soluble carbon, suggesting decreased microbial demand for carbon as shrub cover and carbon stores increase. Lower glucosidase activity in areas with high carbon input from shrubs implies that microbes are decomposing carbon less readily than carbon is being put into the soil. Increasing soil carbon stores in shrub covered areas can lead to shrubs becoming a net carbon sink and a negative feedback to changing climate.

  8. 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.

  9. Active Layer Soil Carbon and Nutrient Mineralization, Barrow, Alaska, 2012

    DOE Data Explorer

    Stan D. Wullschleger; Holly M. Vander Stel; Colleen Iversen; Victoria L. Sloan; Richard J. Norby; Mallory P. Ladd; Jason K. Keller; Ariane Jong; Joanne Childs; Deanne J. Brice

    2015-10-29

    This data set consists of bulk soil characteristics as well as carbon and nutrient mineralization rates of active layer soils manually collected from the field in August, 2012, frozen, and then thawed and incubated across a range of temperatures in the laboratory for 28 day periods in 2013-2015. The soils were collected from four replicate polygons in each of the four Areas (A, B, C, and D) of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska. Soil samples were coincident with the established Vegetation Plots that are located in center, edge, and trough microtopography in each polygon. Data included are 1) bulk soil characteristics including carbon, nitrogen, gravimetric water content, bulk density, and pH in 5-cm depth increments and also by soil horizon, 2) carbon, nitrogen, and phosphorus mineralization rates for soil horizons incubated aerobically (and in one case both aerobically and anaerobically) for 28 days at temperatures that included 2, 4, 8, and 12 degrees C. Additional soil and incubation data are forthcoming. They will be available when published as part of another paper that includes additional replicate analyses.

  10. Nanofiltration and granular activated carbon treatment of perfluoroalkyl acids.

    PubMed

    Appleman, Timothy D; Dickenson, Eric R V; Bellona, Christopher; Higgins, Christopher P

    2013-09-15

    Perfluoroalkyl acids (PFAAs) are of concern because of their persistence in the environment and the potential toxicological effects on humans exposed to PFAAs through a variety of possible exposure routes, including contaminated drinking water. This study evaluated the efficacy of nanofiltration (NF) and granular activated carbon (GAC) adsorption in removing a suite of PFAAs from water. Virgin flat-sheet NF membranes (NF270, Dow/Filmtec) were tested at permeate fluxes of 17-75 Lm(-2)h(-1) using deionized (DI) water and artificial groundwater. The effects of membrane fouling by humic acid on PFAA rejection were also tested under constant permeate flux conditions. Both virgin and fouled NF270 membranes demonstrated >93% removal for all PFAAs under all conditions tested. GAC efficacy was tested using rapid small-scale columns packed with Calgon Filtrasorb300 (F300) carbon and DI water with and without dissolved organic matter (DOM). DOM effects were also evaluated with F600 and Siemens AquaCarb1240C. The F300 GAC had <20% breakthrough of all PFAAs in DI water for up to 125,000 bed volumes (BVs). When DOM was present, >20% breakthrough of all PFAAs by 10,000 BVs was observed for all carbons.

  11. Completeness assessment of type II active pharmaceutical ingredient drug master files under generic drug user fee amendment: review metrics and common incomplete items.

    PubMed

    Zhang, Huyi; Li, Haitao; Song, Wei; Shen, Diandian; Skanchy, David; Shen, Kun; Lionberger, Robert A; Rosencrance, Susan M; Yu, Lawrence X

    2014-09-01

    Under the Generic Drug User Fee Amendments (GDUFA) of 2012, Type II active pharmaceutical ingredient (API) drug master files (DMFs) must pay a user fee and pass a Completeness Assessment (CA) before they can be referenced in an Abbreviated New Drug Application (ANDA), ANDA amendment, or ANDA prior approval supplement (PAS). During the first year of GDUFA implementation, from October 1, 2012 to September 30, 2013, approximately 1,500 Type II API DMFs received at least one cycle of CA review and more than 1,100 Type II DMFs were deemed complete and published on FDA's "Available for Reference List". The data from CA reviews were analyzed for factors that influenced the CA review process and metrics, as well as the areas of DMF submissions which most frequently led to an incomplete CA status. The metrics analysis revealed that electronic DMFs appear to improve the completeness of submission and shorten both the review and response times. Utilizing the CA checklist to compile and proactively update the DMFs improves the chance for the DMFs to pass the CA in the first cycle. However, given that the majority of DMFs require at least two cycles of CA before being deemed complete, it is recommended that DMF fees are paid 6 months in advance of the ANDA submissions in order to avoid negatively impacting the filling status of the ANDAs.

  12. Possible conduction mechanisms in coconut-shell activated carbon

    NASA Astrophysics Data System (ADS)

    Daud, W. M.; Badri, M.; Mansor, H.

    1990-02-01

    This work reports on the result of electrical conductivity measurements carried out on coconut-shell activated carbon. The results suggest that the charge carriers moved by variable-range hopping below 200 K, by hopping among localized energy states between 200 K and 385 K, and by percolation through energy states close to the mobility edge above 385 K. In the latter two conduction processes, significant additional frequency-dependent contributions to the conductivity were observed and are tentatively attributed to polarization of unremovable lignin and/or ionic impurities. These explanations are based on the present trends of the electrical transport theory for amorphous semiconductors.

  13. Electric Pulse Discharge Activated Carbon Supercapacitors for Transportation Application

    NASA Astrophysics Data System (ADS)

    Nayak, Subhadarshi; Agrawal, Jyoti

    2012-03-01

    ScienceTomorrow is developing a high-speed, low-cost process for synthesizing high-porosity electrodes for electrochemical double-layer capacitors. Four types of coal (lignite, subbituminous, bituminous, and anthracite) were used as precursor materials for spark discharge activation with multiscale porous structure. The final porosity and pore distribution depended, among other factors, on precursor type. The high gas content in low-grade carbon resulted in mechanical disintegration, whereas high capacitance was attained in higher-grade coal. The properties, including capacitance, mechanical robustness, and internal conductivity, were excellent when the cost is taken into consideration.

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

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Yavrouian, Andre

    1996-01-01

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

  15. Conducting polymer transistors making use of activated carbon gate electrodes.

    PubMed

    Tang, Hao; Kumar, Prajwal; Zhang, Shiming; Yi, Zhihui; Crescenzo, Gregory De; Santato, Clara; Soavi, Francesca; Cicoira, Fabio

    2015-01-14

    The characteristics of the gate electrode have significant effects on the behavior of organic electrochemical transistors (OECTs), which are intensively investigated for applications in the booming field of organic bioelectronics. In this work, high specific surface area activated carbon (AC) was used as gate electrode material in OECTs based on the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS). We found that the high specific capacitance of the AC gate electrodes leads to high drain-source current modulation in OECTs, while their intrinsic quasi-reference characteristics make unnecessary the presence of an additional reference electrode to monitor the OECT channel potential.

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

    PubMed

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

    2015-04-01

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

  17. 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

  18. Effect of activator on the structure and desulphurization efficiency of sludge-activated carbon.

    PubMed

    Li, Fen; Yan, Bo; Zhang, Yanping; Zhang, Linhuan; Lei, Tao

    2014-01-01

    Sludge-activated carbons (SACs) prepared with excess of activated sludge are used to solve the problems of sludge disposal and odour pollution in a sewage treatment plant. For the preparation, ZnCl2, KOH and H2SO4 are used as activators, respectively. The structure of the SACs are characterized by scanning electron microscope, X-ray photoelectron spectrometer, specific surface area and pore structure technologies, and the adsorption performance of H2S is investigated. Results indicate that the desulphurization activity of SACs, whose activators are ZnCl2 and KOH (SACZ and SACK), is better than that of carbon with H2SO4 as the activator (SACH). The breakthrough time of SACZ and SACK is up to 86 min, the sulphur capacity is 7.7 mg/cm3, and the maximal iodine value is 409.95 mg/g. While the breakthrough time of SACH is only 26 min with the sulphur capacity of 2.3 mg/cm3. A large percentage of pore volume with a diameter of 2-5 nm in the total pore volume is conductive to the desulphurization reaction. The large amount of surface acid functional groups is also helpful to the adsorption of H2S. The desulphurization activity of SACZ and SACK is superior over that of commercial-activated carbon.

  19. Removal of nitrate from aqueous solutions by activated carbon prepared from sugar beet bagasse.

    PubMed

    Demiral, Hakan; Gündüzoğlu, Gül

    2010-03-01

    In this study, activated carbons were prepared from sugar beet bagasse by chemical activation and the prepared activated carbons were used to remove nitrate from aqueous solutions. In chemical activation, ZnCl(2) was used as chemical agent. The effects of impregnation ratio and activation temperature were investigated. The produced activated carbons were characterized by measuring their porosities and pore size distributions. The microstructure of the activated carbons was examined by scanning electron microscopy (SEM). The maximum specific surface area of the activated carbon was about 1826m(2)/g at 700 degrees C and at an impregnation ratio of 3:1. The resulting activated carbon was used for removal of nitrate from aqueous solution. The effects of pH, temperature and contact time were investigated. Isotherm studies were carried out and the data were analyzed by Langmuir, Freundlich and Temkin equations. Three simplified kinetic models were tested to investigate the adsorption mechanism.

  20. Carbonic anhydrase activity in isolated chloroplasts of chlamydomonas reinhardtii

    SciTech Connect

    Katzman, G.; Togasaki, R.K. ); Marcus, Y. ); Moroney, J.V. )

    1989-04-01

    In a new assay of carbonic anhydrase, NaH{sup 14}CO{sub 3} solution at the bottom of a sealed vessel releases {sup 14}CO{sub 3} which diffuses to the top of the vessel to be assimilated by actively photosynthesizing Chlamydomonas cells. The assay is initiated by illuminating cells and stopped by turning the light off and killing the cells with acid. Enzyme activity was estimated from acid stable radioactivity above the uncatalyzed background level. With bovine carbonic anhydrase, 1.5 Wilbur Anderson Unit (WAU) can be consistantly measured at 5-6 fold above background. Sonicated whole cells of air adapted wild type (+)gave 741.1 {plus minus} 12.4 WAU/mg chl. Intact washed cells of mixotrophically grown wall-less mutant CWD(-) and a high CO2 requiring wall-less double mutant CIA-3/CW15 (-) gave 7.1 {plus minus} 1.9 and 2.8 {plus minus} 7.8 WAU/mg chl respectively. Chloroplasts isolated from CWD and CIA-3/CW15 and subsequently disrupted gave 64.0 {plus minus} 14.7 and 2.8 {plus minus} 3.2 WAU/mg chl respectively. Chloroplast sonicate from another wall-less mutant CW15(-) gave activity comparable to CWD. Thus on a chlorophyll basis, enzyme activity in chloroplasts from mixotrophically grown cells is about 1/10th of the level found in air adapted wild type cells. CIA-3 seems to lack this activity.

  1. The Constitutional Amendment Process

    ERIC Educational Resources Information Center

    Chism, Kahlil

    2005-01-01

    This article discusses the constitutional amendment process. Although the process is not described in great detail, Article V of the United States Constitution allows for and provides instruction on amending the Constitution. While the amendment process currently consists of six steps, the Constitution is nevertheless quite difficult to change.…

  2. Short-term effects of different organic amendments on soil chemical, biochemical and biological indicators

    NASA Astrophysics Data System (ADS)

    Mondelli, Donato; Aly, Adel; Yirga Dagnachew, Ababu; Piscitelli, Lea; Dumontet, Stefano; Miano, Teodoro

    2014-05-01

    The limited availability of animal manure and the high cost of good quality compost lead to difficult soil quality management under organic agriculture. Therefore, it is important to find out alternative organic soil amendments and more flexible strategies that are able to sustain crop productivity and maintain and enhance soil quality. A three years study was carried out in the experimental fields of the Mediterranean Agronomic Institute of Bari located in Valenzano, Italy. The main objective of this research is to investigate the effects of different fertility management strategies on soil quality in order to estimate the role of innovative matrices for their use in organic farming. The experiment consists of seven treatments applied to a common crop rotation. The treatments include alternative organic amendments (1- olive mill wastewater OMW, 2- residues of mushroom cultivation MUS, 3- coffee chaff COF), common soil amendments (4- compost COM, 5- faba bean intercropping LEG, 6- cow manure - MAN) and as a reference treatment (7- mineral fertilizer COV). The soil quality was assessed before and after the application of the treatments, through biological (microbial biomass carbon and nitrogen, soil respiration and metabolic quotient), biochemical (soil enzymatic activities: β-glucosidase, alkaline phospatase, urease, fluorescein diacetate (FDA) hydrolysis), and chemical (pH, soil organic carbon, soil organic matter, total nitrogen, available phosphorous, exchangeable potassium, dissolved organic carbon and total dissolved nitrogen) indicators. Based on the results obtained after the second year, all treatments were able to improve various soil chemical parameters as compared to mineral fertilizer. The incorporation of COF and OMW seemed to be more effective in improving soil total N and exchangeable K, while MAN significantly increased available P. All the amendments enhance dissolved organic C, soil respiration, microbial biomass and metabolic quotient as

  3. First Amendment Protects Tobacco Advertising.

    ERIC Educational Resources Information Center

    Fein, Bruce

    1988-01-01

    Argues that the U.S. government suppression of tobacco advertising is inconsistent with the First Amendment. Cites court decisions declaring that truthful commercial speech concerning lawful activity can be suppressed only if restraint directly advances a substantial government interest. Concludes that Congress should repeal prohibition on…

  4. Heterogeneity of biochar amendment to improve the carbon and nitrogen sequestration through reduce the greenhouse gases emissions during sewage sludge composting.

    PubMed

    Awasthi, Mukesh Kumar; Wang, Meijing; Chen, Hongyu; Wang, Quan; Zhao, Junchao; Ren, Xiuna; Li, Dong-Sheng; Awasthi, Sanjeev Kumar; Shen, Feng; Li, Ronghua; Zhang, Zengqiang

    2017-01-01

    This study was performed to investigate the effects of biochar as an amendment to a gaseous emissions and sewage sludge (SS) composting dynamics. Six dosage of biochar [low dosage of biochar (LDB) - 2%, 4% and 6%; and higher dosage of biochar (HDB) - 8%, 12% and 18%] were amended to a mixture of SS and wheat straw (4:1 ratio on dry weight basis) and compared to control or without additive. The HDB significantly reduced CH4, N2O and NH3 emission by 92.85-95.34%, 95.14-97.30% and 58.03-65.17%, but not the CO2 emission. Meanwhile, humification results indicated that humic and fulvic acid 35-42% and 24-28% higher in the HDB amended treatments than those in the LDB and control treatments. The HDB significantly decreased total nitrogen losses and greenhouse gas emission, while LDB had significantly (p<0.001) higher CH4 and N2O emissions. Due to effective performance of HDB, the 12% biochar was recommended to be used in SS composting practice.

  5. Dye removal of activated carbons prepared from NaOH-pretreated rice husks by low-temperature solution-processed carbonization and H3PO4 activation.

    PubMed

    Chen, Yun; Zhai, Shang-Ru; Liu, Na; Song, Yu; An, Qing-Da; Song, Xiao-Wei

    2013-09-01

    A coupling of low-temperature sulfuric acid-assisted carbonization and H3PO4 activation was employed to convert NaOH-pretreated rice husks into activated carbons with extremely high surface area (2028 m(2) g(-1)) and integrated characteristics. The influences of the activation temperature and impregnation ratio on the surface area, pore volume of activated carbons were thoroughly investigated. The morphology and surface chemistry of activated carbons were characterized using N2 sorption, FTIR, XPS, SEM, TEM, etc. The adsorption capacity of resulting carbons obtained under optimum preparation conditions was systematically evaluated using methylene blue under various simulated conditions. The adsorption process can be well described by both Langmuir isotherm model and the pseudo-second order kinetics models; and the maximum monolayer capacity of methylene blue was ca. 578 mg g(-1).

  6. Surface heterogeneity effects of activated carbons on the kinetics of paracetamol removal from aqueous solution

    NASA Astrophysics Data System (ADS)

    Ruiz, B.; Cabrita, I.; Mestre, A. S.; Parra, J. B.; Pires, J.; Carvalho, A. P.; Ania, C. O.

    2010-06-01

    The removal of a compound with therapeutic activity (paracetamol) from aqueous solutions using chemically modified activated carbons has been investigated. The chemical nature of the activated carbon material was modified by wet oxidation, so as to study the effect of the carbon surface chemistry and composition on the removal of paracetamol. The surface heterogeneity of the carbon created upon oxidation was found to be a determinant in the adsorption capability of the modified adsorbents, as well as in the rate of paracetamol removal. The experimental kinetic data were fitted to the pseudo-second order and intraparticle diffusion models. The parameters obtained were linked to the textural and chemical features of the activated carbons. After oxidation the wettability of the carbon is enhanced, which favors the transfer of paracetamol molecules to the carbon pores (smaller boundary layer thickness). At the same time the overall adsorption rate and removal efficiency are reduced in the oxidized carbon due to the competitive effect of water molecules.

  7. Ecotoxicological effects of activated carbon addition to sediments.

    PubMed

    Jonker, Michiel T O; Suijkerbuijk, Martin P W; Schmitt, Heike; Sinnige, Theo L

    2009-08-01

    Activated carbon (AC) addition is a recently developed technique for the remediation of sediments and soils contaminated with hydrophobic organic chemicals. Laboratory and field experiments have demonstrated that the addition of 3-4% of AC can reduce aqueous concentrations and the bioaccumulation potential of contaminants. However, one aspect of the technique that has hardly received any attention is the possible occurrence of secondary, eco(toxico)logical effects, i.e., effects of AC addition on the health, behavior, and habitat quality of local organisms. In the present study, several ecotoxicological effects were investigated in AC-water and AC-enriched (0-25%) sediment systems. It was demonstrated that (i) powdered activated carbons can be toxic to aquatic invertebrates (Lumbriculus variegatus, Daphnia magna, and Corophium volutator) based on different mechanisms and preferably should be washed prior to application; (ii) Asellus aquaticus and Corophium volutator may physically avoid AC-enriched sediments; (iii) exposure of Lumbriculus variegatus to AC-enriched sediments lead to a time and dose-dependent reduction in the worms' lipid content, which was most probably caused by the observation that (iv) worm egestion rates decreased drastically upon AC addition, indicating that the presence of AC disturbed feeding behavior; and (v) there were no obvious effects on the microbiological community structure. All in all, these results suggest potential ecotoxicological effects of powdered AC addition and stress the need for a detailed further investigation of secondary effects of the technique, prior to any large-scale field application.

  8. Water treatment using activated carbon supporting silver and magnetite.

    PubMed

    Valušová, Eva; Vandžurová, Anna; Pristaš, Peter; Antalík, Marián; Javorský, Peter

    2012-01-01

    Recent efforts in water purification have led to the development of novel materials whose unique properties can offer effective biocidal capabilities with greater ease of use and at lower cost. In this study, we introduce a novel procedure for the preparation of activated carbon (charcoal) composite in which magnetite and silver are incorporated (MCAG); we also describe the use of this material for the disinfection of surface water. The formation process of magnetic MCAG composite was studied using ultraviolet-visible spectroscopy. The results demonstrated the high sorption efficiency of AgNO₃ to magnetic activated carbon. The antimicrobial capabilities of the prepared MCAG were examined and the results clearly demonstrate their inhibitory effect on total river water bacteria and on Pseudomonas koreensis and Bacillus mycoides cultures isolated from river water. The bacterial counts in river water samples were reduced by five orders of magnitude following 30 min of treatment using 1 g l⁻¹ of MCAG at room temperature. The removal of all bacteria from the surface water samples implies that the MCAG material would be a suitable disinfectant for such waters. In combination with its magnetic character, MCAG would be an excellent candidate for the simple ambulatory disinfection of surface water.

  9. 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.

  10. 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.

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

    SciTech Connect

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

    1995-02-01

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

  12. Characterization of activated carbon prepared from chicken waste and coal

    SciTech Connect

    Yan Zhang; Hong Cui; Riko Ozao; Yan Cao; Bobby I.-T. Chen; Chia-Wei Wang; Wei-Ping Pan

    2007-12-15

    Activated carbons (ACs) were prepared from chicken waste (CW) and coal (E-coal) blended at the ratios of 100:0, 80:20, 50:50, 20:80, and 0:100. The process included carbonization in flowing gaseous nitrogen (300 mL min{sup -1}) at ca. 430{sup o}C for 60 min and successive steam activation (0.1 mL min{sup -1} water injection with a flow of N{sub 2} at 100 mL min{sup -1}) at 650{sup o}C for 30 min. Chicken waste is low in sulfur content but is high in volatile matter (about 55 wt %), and ACs with higher specific surface area were more successfully obtained by mixing with coal. The specific surface area of the CW/Coal blend AC can be estimated by SSA{sub BET} = -65.8x{sup 2} + 158x + 168, where SSA{sub BET} is the specific surface area in m{sup 2} g{sup -1} as determined by the BET method using CO{sub 2} as the adsorbent, where x is the coal fraction by weight in the CW/coal blend ranging from 0.0 to 1.0 (e.g., x = 0.0 signifies the blend contains no coal and x = 1.0 signifies the blend consists of 100% coal). 26 refs., 7 figs., 3 tabs.

  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. An active, flexible carbon nanotube microelectrode array for recording electrocorticograms

    NASA Astrophysics Data System (ADS)

    Chen, Yung-Chan; Hsu, Hui-Lin; Lee, Yu-Tao; Su, Huan-Chieh; Yen, Shiang-Jie; Chen, Chang-Hsiao; Hsu, Wei-Lun; Yew, Tri-Rung; Yeh, Shih-Rung; Yao, Da-Jeng; Chang, Yen-Chung; Chen, Hsin

    2011-06-01

    A variety of microelectrode arrays (MEAs) has been developed for monitoring intra-cortical neural activity at a high spatio-temporal resolution, opening a promising future for brain research and neural prostheses. However, most MEAs are based on metal electrodes on rigid substrates, and the intra-cortical implantation normally causes neural damage and immune responses that impede long-term recordings. This communication presents a flexible, carbon-nanotube MEA (CMEA) with integrated circuitry. The flexibility allows the electrodes to fit on the irregular surface of the brain to record electrocorticograms in a less invasive way. Carbon nanotubes (CNTs) further improve both the electrode impedance and the charge-transfer capacity by more than six times. Moreover, the CNTs are grown on the polyimide substrate directly to improve the adhesion to the substrate. With the integrated recording circuitry, the flexible CMEA is proved capable of recording the neural activity of crayfish in vitro, as well as the electrocorticogram of a rat cortex in vivo, with an improved signal-to-noise ratio. Therefore, the proposed CMEA can be employed as a less-invasive, biocompatible and reliable neuro-electronic interface for long-term usage.

  15. Adsorption of basic dyes onto activated carbon using microcolumns

    SciTech Connect

    El Qada, E.N.; Allen, S.J.; Walker, G.M.

    2006-08-16

    Column studies for the adsorption of basic dyes (methylene blue, basic red, and basic yellow) onto PAC2 (activated carbon produced from bituminous coal using steam activation) and F400 were undertaken in fixed-bed microcolumns. Experimental data were correlated using the bed depth service time (BDST) model. The effect of bisolute interactions on the performance of microcolumn fixed beds was studied. The BDST model was successful in describing the breakthrough curves for the adsorption of MB onto PAC2 and predicts the experimental data with a good degree of accuracy. The results emphasized that the interactions and competition for the available binding sites have considerable influence on the efficiency of adsorbents to remove dyes from the solution.

  16. Electrical Activation of Dark Excitonic States in Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Uda, Takushi; Yoshida, Masahiro; Ishii, Akihiro; Kato, Yuichiro K.

    Electrical activation of optical transitions to parity-forbidden dark excitonic states in individual carbon nanotubes is reported. We examine electric field effects on various excitonic states by simultaneously measuring both photocurrent and photoluminescence. As the applied field increases, we observe an emergence of new absorption peaks in the excitation spectra. From the diameter dependence of the energy separation between the new peaks and the ground state of E11 excitons, we attribute the peaks to the dark excited states which became optically active due to the applied field. A simple field-induced exciton dissociation model is introduced to explain the photocurrent threshold fields, and the edge of the E11 continuum states have been identified using this model. Work supported by JSPS (KAKENHI 24340066, 26610080), MEXT (Photon Frontier Network Program, Nanotechnology Platform), Canon Foundation, and Asahi Glass Foundation.

  17. Crystallinity Modulation of Layered Carbon Nitride for Enhanced Photocatalytic Activities

    PubMed Central

    Wang, Jianhai; Shen, Yanfei; Li, Ying; Liu, Songqin

    2016-01-01

    Abstract As an emerging metal‐free semiconductor, covalently bonded carbon nitride (CN) has attracted much attention in photocatalysis. However, drawbacks such as a high recombination rate of excited electrons and holes hinder its potential applications. Tailoring the crystallinity of semiconductors is an important way to suppress unwanted charge recombination, but has rarely been applied to CN so far. Herein, a simple method to synthesize CN of high crystallinity by protonation of specific intermediate species during conventional polymerization is reported. Interestingly, the as‐obtained CN exhibited improved photocatalytic activities of up to seven times those of the conventional bulk CN. This approach, with only a slight change to the conventional method, provides a facile way to effectively regulate the crystallinity of bulk CN to improve its photocatalytic activities and sheds light on large‐scale industrial applications of CN with high efficiency for sustainable energy. PMID:27436164

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. Metal Ion Adsorption by Activated Carbons Made from Pecan Shells: Effect of Oxygen Level During Activation

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    NASA Astrophysics Data System (ADS)

    Arampatzidou, An; Deliyanni, Eleni A.

    2015-04-01

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

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

    PubMed

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

    2013-03-05

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

  2. Porous carbon nitride nanosheets for enhanced photocatalytic activities

    NASA Astrophysics Data System (ADS)

    Hong, Jindui; Yin, Shengming; Pan, Yunxiang; Han, Jianyu; Zhou, Tianhua; Xu, Rong

    2014-11-01

    Porous carbon nitride nanosheets (PCNs) have been prepared for the first time by a simple liquid exfoliation method via probe sonication. These mesoporous nanosheets of around 5 nm in thickness combine several advantages including high surface area, enhanced light absorption and excellent water dispersity. It can be used as a versatile support for co-catalyst loading for photocatalytic dye degradation and water reduction. With 3.8 wt% Co3O4 loaded, PCNs can achieve more efficient photocatalytic degradation of Rhodamine B, compared with non-porous C3N4 nanosheets (CNs), bulk porous C3N4 (PCN) and bulk nonporous C3N4 (CN). With 1.0 wt% Pt loaded, CNs and PCN exhibit 7-8 times enhancement in H2 evolution than CN. Remarkably, PCNs with both porous and nanosheet-like features achieve 26 times higher activity in H2 evolution than CN. These significant improvements in photocatalytic activities can be attributed to the high surface area as well as better electron mobility of the two-dimensional nanostructure.Porous carbon nitride nanosheets (PCNs) have been prepared for the first time by a simple liquid exfoliation method via probe sonication. These mesoporous nanosheets of around 5 nm in thickness combine several advantages including high surface area, enhanced light absorption and excellent water dispersity. It can be used as a versatile support for co-catalyst loading for photocatalytic dye degradation and water reduction. With 3.8 wt% Co3O4 loaded, PCNs can achieve more efficient photocatalytic degradation of Rhodamine B, compared with non-porous C3N4 nanosheets (CNs), bulk porous C3N4 (PCN) and bulk nonporous C3N4 (CN). With 1.0 wt% Pt loaded, CNs and PCN exhibit 7-8 times enhancement in H2 evolution than CN. Remarkably, PCNs with both porous and nanosheet-like features achieve 26 times higher activity in H2 evolution than CN. These significant improvements in photocatalytic activities can be attributed to the high surface area as well as better electron mobility of

  3. Activated carbons prepared from refuse derived fuel and their gold adsorption characteristics.

    PubMed

    Buah, William K; Williams, Paul T

    2010-02-01

    Activated carbons produced from refuse derived fuel (RDF), which had been prepared from municipal solid waste have been characterized and evaluated for their potential for gold adsorption from gold chloride solution. Pyrolysis of the RDF produced a char, which was then activated via steam gasification to produce activated carbons. Steam gasification of the char at 900 degrees C for 3 h yielded 73 wt% activated carbon. The derived activated carbon had a surface area of 500 m2 g(-1) and a total pore volume of 0.19 cm3 g(-1). The gold adsorption capacity of the activated carbon was 32.1 mg Au g(-1) of carbon when contacted with an acidified gold chloride solution. The gold adsorption capacity was comparable to that of a commercial activated carbon tested under the same conditions and was well in the range of values of activated carbons used in the gold industry. Demineralization of the RDF activated carbon in a 5 M HCl solution resulted in enhancement of its textural properties but a reduction in the gold adsorption rate, indicating that the metal content of the RDF activated carbon influenced its gold adsorption rate.

  4. 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.

  5. Assessment of the use of sorbent amendments for reduction of mercury methylation in wetland sediments at Acadia National Park, Maine

    USGS Publications Warehouse

    Huntington, Thomas G.; Lewis, Ariel; Amirbahman, Aria; Marvin-DiPasquale, Mark C.; Culbertson, Charles W.

    2015-01-01

    The results of field mesocosm experiments indicated that there was a decreasing trend in pore-water methylmercury concentration after application of granular activated carbon but methylation was not affected because there was no corresponding decrease in sediment methylmercury concentration. The application of granular activated carbon resulted in the sorption of methylmercury. The application of granular activated carbon resulted in an increase in the distribution coefficient for methylmercury indicating that this amendment caused a higher proportion of methylmercury to be associated with the sediment than the pore water in comparison to the reference (untreated) condition. Experiments to test whether zero-valent iron or granular activated carbon would reduce the biouptake of methylmercury in snails were inconsistent; zero-valent iron had no effect on uptake in one experiment but resulted in a significant decrease in uptake in a second experiment. Granular activated carbon did not affect biouptake in either experiment.

  6. Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH.

    PubMed

    Uchimiya, Minori; Bannon, Desmond I

    2013-08-14

    Biochar is often considered a strong heavy metal stabilizing agent. However, biochar in some cases had no effects on, or increased the soluble concentrations of, heavy metals in soil. The objective of this study was to determine the factors causing some biochars to stabilize and others to dissolve heavy metals in soil. Seven small arms range soils with known total organic carbon (TOC), cation exchange capacity, pH, and total Pb and Cu contents were first screened for soluble Pb and Cu concentrations. Over 2 weeks successive equilibrations using weak acid (pH 4.5 sulfuric acid) and acetate buffer (0.1 M at pH 4.9), Alaska soil containing disproportionately high (31.6%) TOC had nearly 100% residual (insoluble) Pb and Cu. This soil was then compared with sandy soils from Maryland containing significantly lower (0.5-2.0%) TOC in the presence of 10 wt % (i) plant biochar activated to increase the surface-bound carboxyl and phosphate ligands (PS450A), (ii) manure biochar enriched with soluble P (BL700), and (iii) unactivated plant biochars produced at 350 °C (CH350) and 700 °C (CH500) and by flash carbonization (corn). In weak acid, the pH was set by soil and biochar, and the biochars increasingly stabilized Pb with repeated extractions. In pH 4.9 acetate buffer, PS450A and BL700 stabilized Pb, and only PS450A stabilized Cu. Surface ligands of PS450A likely complexed and stabilized Pb and Cu even under acidic pH in the presence of competing acetate ligand. Oppositely, unactivated plant biochars (CH350, CH500, and corn) mobilized Pb and Cu in sandy soils; the putative mechanism is the formation of soluble complexes with biochar-borne dissolved organic carbon. In summary, unactivated plant biochars can inadvertently increase dissolved Pb and Cu concentrations of sandy, low TOC soils when used to stabilize other contaminants.

  7. 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 a