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Sample records for activated carbon filtration

  1. Removal of diclofenac by conventional drinking water treatment processes and granular activated carbon filtration.

    Rigobello, Eliane Sloboda; Dantas, Angela Di Bernardo; Di Bernardo, Luiz; Vieira, Eny Maria

    2013-06-01

    This study was carried out to evaluate the efficiency of conventional drinking water treatment processes with and without pre-oxidation with chlorine and chlorine dioxide and the use of granular activated carbon (GAC) filtration for the removal of diclofenac (DCF). Water treatment was performed using the Jar test with filters on a lab scale, employing nonchlorinated artesian well water prepared with aquatic humic substances to yield 20HU true color, kaolin turbidity of 70 NTU and 1mgL(-1) DCF. For the quantification of DCF in water samples, solid phase extraction and HPLC-DAD methods were developed and validated. There was no removal of DCF in coagulation with aluminum sulfate (3.47mgAlL(-1) and pH=6.5), flocculation, sedimentation and sand filtration. In the treatment with pre-oxidation and disinfection, DCF was partially removed, but the concentration of dissolved organic carbon (DOC) was unchanged and byproducts of DCF were observed. Chlorine dioxide was more effective than chorine in oxidizing DCF. In conclusion, the identification of DCF and DOC in finished water indicated the incomplete elimination of DCF through conventional treatments. Nevertheless, conventional drinking water treatment followed by GAC filtration was effective in removing DCF (⩾99.7%). In the oxidation with chlorine, three byproducts were tentatively identified, corresponding to a hydroxylation, aromatic substitution of one hydrogen by chlorine and a decarboxylation/hydroxylation. Oxidation with chlorine dioxide resulted in only one byproduct (hydroxylation). PMID:23540811

  2. How to dose powdered activated carbon in deep bed filtration for efficient micropollutant removal.

    Altmann, Johannes; Ruhl, Aki S; Sauter, Daniel; Pohl, Julia; Jekel, Martin

    2015-07-01

    Direct addition of powdered activated carbon (PAC) to the inlet of a deep bed filter represents an energy- and space-saving option to remove organic micropollutants (OMPs) during advanced wastewater treatment or drinking water purification. In this lab-scale study, continuous dosing, preconditioning a filter with PAC and combinations thereof were investigated as possible dosing modes with respect to OMP adsorption efficiency. Continuous dosing resulted in decreasing effluent concentrations with increasing filter runtime due to adsorption onto accumulating PAC in the filter bed. Approximately constant removal levels were achieved at longer filter runtimes, which were mainly determined by the dose of fresh PAC, rather than the total PAC amount embedded. The highest effluent concentrations were observed during the initial filtration stage. Meanwhile, preconditioning led to complete OMP adsorption at the beginning of filtration and subsequent gradual OMP breakthrough. PAC distribution in the pumice filter was determined by the loss on ignition of PAC and pumice and was shown to be relevant for adsorption efficiency. Preconditioning with turbulent upflow led to a homogenous PAC distribution and improved OMP adsorption significantly. Combining partial preconditioning and continuous dosing led to low initial effluent concentrations, but ultimately achieved concentrations similar to filter runs without preconditioning. Furthermore, a dosing stop prior to the end of filtration was suitable to increase PAC efficiency without affecting overall OMP removals. PMID:25898248

  3. Removal of micropollutants and reduction of biological activity in a full scale reclamation plant using ozonation and activated carbon filtration.

    Reungoat, J; Macova, M; Escher, B I; Carswell, S; Mueller, J F; Keller, J

    2010-01-01

    Pharmaceutical compounds are found in secondary treated effluents up to microg L(-1) levels and therefore discharged into surface waters. Since the long term effects of these compounds on the environment and human health are, to date, largely unknown, implementation of advanced treatment of wastewaters is envisaged to reduce their discharge. This is of particular relevance where surface waters are used as drinking water sources and when considering indirect potable reuse. This study aimed at assessing the removal of organic micropollutants and the concurrent reduction of their biological activity in a full scale reclamation plant treating secondary effluent. The treatment consists of 6 stages: denitrification, pre-ozonation, coagulation/flocculation/dissolved air flotation and filtration (DAFF), main ozonation, activated carbon filtration and final ozonation for disinfection. For that purpose, representative 24-hour composite samples were collected after each stage. The occurrence of 85 compounds was monitored by LC/MS-MS. A battery of 6 bioassays was also used as a complementary tool to evaluate non-specific toxicity and 5 specific toxic modes of action. Results show that, among the 54 micropollutants quantified in the influent water, 50 were removed to below their limit of quantification representing more than 90% of concentration reduction. Biological activity was reduced, depending on the specific response that was assessed, from a minimum of 62% (AhR response) to more than 99% (estrogenicity). The key processes responsible for the plant's performances were the coagulation/flocculation/DAFF, main ozonation and activated carbon filtration. The effect of these 3 processes varied from one compound or bioassay to another but their combination was almost totally responsible for the overall observed reduction. Bioassays yielded complementary information, e.g. estrogenic compounds were not detected in the secondary effluent by chemical analysis, but the samples had an

  4. Combination of granular activated carbon adsorption and deep-bed filtration as a single advanced wastewater treatment step for organic micropollutant and phosphorus removal.

    Altmann, Johannes; Rehfeld, Daniel; Träder, Kai; Sperlich, Alexander; Jekel, Martin

    2016-04-01

    Adsorption onto granular activated carbon (GAC) is an established technology in water and advanced wastewater treatment for the removal of organic substances from the liquid phase. Besides adsorption, the removal of particulate matter by filtration and biodegradation of organic substances in GAC contactors has frequently been reported. The application of GAC as both adsorbent for organic micropollutant (OMP) removal and filter medium for solids retention in tertiary wastewater filtration represents an energy- and space saving option, but has rarely been considered because high dissolved organic carbon (DOC) and suspended solids concentrations in the influent of the GAC adsorber put a significant burden on this integrated treatment step and might result in frequent backwashing and unsatisfactory filtration efficiency. This pilot-scale study investigates the combination of GAC adsorption and deep-bed filtration with coagulation as a single advanced treatment step for simultaneous removal of OMPs and phosphorus from secondary effluent. GAC was assessed as upper filter layer in dual-media downflow filtration and as mono-media upflow filter with regard to filtration performance and OMP removal. Both filtration concepts effectively removed suspended solids and phosphorus, achieving effluent concentrations of 0.1 mg/L TP and 1 mg/L TSS, respectively. Analysis of grain size distribution and head loss within the filter bed showed that considerable head loss occurred in the topmost filter layer in downflow filtration, indicating that most particles do not penetrate deeply into the filter bed. Upflow filtration exhibited substantially lower head loss and effective utilization of the whole filter bed. Well-adsorbing OMPs (e.g. benzotriazole, carbamazepine) were removed by >80% up to throughputs of 8000-10,000 bed volumes (BV), whereas weakly to medium adsorbing OMPs (e.g. primidone, sulfamethoxazole) showed removals <80% at <5,000 BV. In addition, breakthrough behavior was

  5. Adsorptive removal of geosmin by ceramic membrane filtration with super-powdered activated carbon

    Matsui, Yoshihiko; Aizawa, Takako; Kanda, Fumiaki; Nigorikawa, Naoko; Mima, Satoru; Kawase, Yuji

    2007-01-01

    Tap water free from unpleasant taste and odour is important for consumer satisfaction. We applied a super-powdered activated carbon (S-PAC) and microfiltration (MF) system to the removal of geosmin, a taste- and odour-causing compound. We used a specially pulverised PAC with a submicron particle size, much smaller than the normal PAC (N-PAC) particle size, as an adsorption pretreatment agent. MF and adsorption pretreatment with S-PAC removed geosmin with considerably greater efficiency and at...

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

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

    2015-08-01

    The presence of nanoconcentrations of persistent pharmaceuticals in treated wastewater effluent and in surface water has been frequently reported. A novel organic-inorganic hybrid sorbent based on adsorbing quarternized poly vinylpyridinium-co-styrene (QPVPcS) to montmorillonite (MMT) was designed for the removal of the anionic micropollutants. QPVPcS-clay composites were characterized by X-ray diffraction, FTIR, thermal gravimetric analysis, Zeta potential and element analysis. Based on these measurements polymer-clay micro- and nanostructures, as a function of polymer loading, were suggested. The affinity of the anionic pharmaceutical, diclofenac (DCF), to the composite was high and did not decrease dramatically with an increase of ionic strength, indicating that the interactions are not only electrostatic. The presence of humic acid (HA) did not hinder DCF removal by the composite; whereas, its filtration by granulated activated carbon (GAC) was compromised in the presence of HA. The kinetics and adsorption at equilibrium of DCF to the composite and to GAC were measured and modeled by the time dependent Langmuir equation. The adsorption of DCF to the composite was significantly faster than to GAC. Accordingly, the filtration of micro- and nanoconcentrations of DCF by composite columns, in the presence of HA, was more efficient than by GAC columns. PMID:26126078

  7. An innovative treatment concept for future drinking water production: fluidized ion exchange-ultrafiltration-nanofiltration-granular activated carbon filtration

    J. C. van Dijk

    2009-01-01

    Full Text Available A new treatment concept for drinking water production from surface water has been investigated on a pilot scale. The treatment concept consists of fluidized ion exchange (FIEX, ultrafiltration (UF, nanofiltration (NF, and granular activated carbon filtration (GAC. The FIEX process removed calcium and other divalent cations; the UF membrane removed particles and micro-organisms; and the NF membrane and GAC removed natural organic matter (NOM and micro-pollutants. This study focused on the prevention of fouling of the UF and scaling of the NF and investigated the overall removal of micro-pollutants by the treatment concept. The results of the experiments showed that in 14 days of continuous operation at a flux of 65 l/h. m2 the UF performance was stable with the FIEX pre-treated feed water without the aid of a coagulant. The scaling of the NF was also not observed even at 97% recovery. Different micro-pollutants were spiked in the NF feed water and their concentrations in the effluent of NF and GAC were measured. The combination of NF and GAC removed most of the micro-pollutants successfully, except for the very polar substances with a molecular weight lower than 100 Daltons.

  8. Upgrade of deep bed filtration with activated carbon dosage for compact micropollutant removal from wastewater in technical scale.

    Löwenberg, Jonas; Zenker, Armin; Krahnstöver, Thérèse; Boehler, Marc; Baggenstos, Martin; Koch, Gerhard; Wintgens, Thomas

    2016-05-01

    The removal of micropollutants from drinking and wastewater by powdered activated carbon (PAC) adsorption has received considerable attention in research over the past decade with various separation options having been investigated. With Switzerland as the first country in the world having adopted a new legislation, which forces about 100 wastewater treatment plants to be upgraded for the removal of organic micropollutants from municipal wastewater, the topic has reached practical relevance. In this study, the process combination of powdered activated carbon (PAC) adsorption and deep bed filtration (DBF) for advanced municipal wastewater treatment was investigated over an extended period exceeding one year of operation in technical scale. The study aimed to determine optimum process conditions to achieve sufficient micropollutant removal in agreement with the new Swiss Water Ordinance under most economic process design. It was shown that the addition of PAC and Fe(3+) as combined coagulation and flocculation agent improved effluent water quality with respect to dissolved organic pollutants as well as total suspended solids (TSS), turbidity and PO4-P concentration in comparison to a DBF operated without the addition of PAC and Fe(3+). Sufficient micropollutant (MP) removal of around 80% was achieved at PAC dosages of 10 mg/L revealing that PAC retained in the filter bed maintained considerable adsorption capacity. In the investigated process combination the contact reactor serves for adsorption as well as for flocculation and allowed for small hydraulic retention times of minimum 10 min while maintaining sufficient MP removal. The flocculation of two different PAC types was shown to be fully concluded after 10-15 min, which determined the flocculation reactor size while both PAC types proved suitable for the application in combination with DBF and showed no significant differences in MP removal. Finally, the capping of PAC dosage during rain water periods, which

  9. TiO2 Photocatalyst Nanoparticle Separation: Flocculation in Different Matrices and Use of Powdered Activated Carbon as a Precoat in Low-Cost Fabric Filtration

    Carlos F. Liriano-Jorge

    2014-01-01

    Full Text Available Separation of photocatalyst nanoparticles is a problem impeding widespread application of photocatalytic oxidation. As sedimentation of photocatalyst particles is facilitated by their flocculation, the influence of common constituents of biologically pretreated wastewaters (NaCl, NaHCO3, and their combination with humic acid sodium salt on flocculation was tested by the pipet method. Results showed that the impact of these substances on TiO2 nanoparticle flocculation is rather complex and strongly affected by pH. When humic acid was present, TiO2 particles did not show efficient flocculation in the neutral and slightly basic pH range. As an alternative to photocatalyst separation by sedimentation, precoat vacuum filtration with powdered activated carbon (PAC over low-cost spunbond polypropylene fabrics was tested in the presence of two PAC types in aqueous NaCl and NaHCO3 solutions as well as in biologically treated greywater and in secondary municipal effluent. PAC concentrations of ≥2 g/L were required in order to achieve a retention of nearly 95% of the TiO2 nanoparticles on the fabric filter when TiO2 concentration was 1 g/L. Composition of the aqueous matrix and PAC type had a slight impact on precoat filtration. PAC precoat filtration represents a potential pretreatment for photocatalyst removal by micro- or ultrafiltration.

  10. An innovative treatment concept for future drinking water production: fluidized ion exchange – ultrafiltration – nanofiltration – granular activated carbon filtration

    J. C. van Dijk

    2009-08-01

    Full Text Available A new treatment concept for drinking water production from surface water has been investigated on a pilot scale. The treatment concept consists of fluidized ion exchange (FIEX, ultrafiltration (UF, nanofiltration (NF, and granular activated carbon filtration (GAC. The FIEX process removed calcium and other divalent cations; the UF membrane removed particles and micro-organisms; and the NF membrane and GAC removed natural organic matter (NOM and micro-pollutants. This study focused on the prevention of fouling of the UF and scaling of the NF and investigated the overall removal of micro-pollutants by the treatment concept. The results of the experiments showed that in 14 days of continuous operation at a flux of 65 l/h m2 the UF performance was stable with the FIEX pre-treated feed water without the aid of a coagulant. The scaling of the NF was also not observed even at 97% recovery. Different micro-pollutants were spiked in the NF feed water and their concentrations in the effluent of NF and GAC were measured. The combination of NF and GAC removed most of the micro-pollutants successfully, except for the very polar substances with a molecular weight lower than 100 Daltons.

  11. Screening culture filtrates of fungi for activity against Tylenchulus semipenetrans

    Verdejo-Lucas, S.; Viera, A.; Stchigel, A. M.; Sorribas, F. J.

    2009-07-01

    Culture filtrates of 20 fungi isolated from citrus soils were screened for their activity against Tylenchulus semipenetrans in both in vitro and greenhouse tests. The filtrates of Talaromyces cyanescens (isolates 2-4 and 2-5), Paecilomyces lilacinus, Chaetomium robustum, Acremonium strictum, Engyodontium album, Myrothecium verrucaria, Emericella rugulosa, and Tarracomyces gigaspora consistently inhibited the motility of second-stage juveniles at various concentrations of the filtrate. Dose-response models were used to determine the filtrate concentration required to inhibit the motility of 50% of the juveniles (CI50). The culture filtrate of P. lilacinus showed the highest activity with a CI50 value of 58% that differed from that of C. robustum (CI50 = 68%), and A. strictum CI50 = 82%. The culture filtrates of P. lilacinus, E. album, and T. cyanescens 2-5 maintained their activity when autoclaved at 120 degree centigrade for 20 min. The autoclaved filtrate of T. cyanescens 2-4 was more effective at inhibiting juvenile motility (CI50 = 28%) than that of T. cyanescens 2-5 (CI50 = 80%), C. robustum (CI50 = 72 %) and P. lilacinus (CI50 = 72%). The culture filtrate of T. cyanescens 2-4 also inhibited egg hatching. Nematode reproduction on Cleopatra mandarin and Carrizo citrange were respectively reduced by the culture filtrate of P. lilacinus and the autoclaved filtrate of T. cyanescens 2-4. These results support the hypothesis that soil fungi may contribute to regulate nematode densities by the production of secondary metabolites with nematicidal activity. (Author) 30 refs.

  12. 砂垫层控制活性炭滤池无脊椎动物穿透研究%Penetration control of invertebrates in the granular activated carbon filtration process with sand bed

    尹文超; 张金松; 刘丽君; 赵岩; 李拓; 林超

    2013-01-01

    In view of the aesthetic problem and potential threat to safe drinking water caused by invertebrates, a series different depth of sand beds were located under granular activated carbon ( GAC ) media in five pilot -GAC filtration (GACF) columns to restrict invertebrates' penetration into the distribution system. During the study period of 10 months, 7 groups of invertebrates ( rotifers and crustaceans as the predominant species) were detected in the filtrates of the five GACF columns. The experimental results indicated that invertebrates could be removed effectively with the added sand beds compared with the sand bed-free GACF column. The mean abundances of invertebrates decreased significantly with the increase of the depth of sand beds. The 46. 6 % of rotifers and 85. 5% of larger invertebrates (size > 200 μm) could be removed from the filtrate. Sand sizes had a greater impact on rotifers removal than larger invertebrates. Also increasing removal ratios of particle matter were detected with the sand beds added. Further data analysis showed that there was significant correlation between the mean values of particle counts and abundances of invertebrates in the filtrates.%为控制无脊椎动物穿透带来的过滤水感官问题和潜在的安全风险,添加一系列不同粒径和不同高度的砂垫层于5根活性炭(Granular activated carbon,GAC)滤柱中.在10个月的连续运行期间,滤柱出水中共检出7类无脊椎动物(其中轮虫和甲壳类生物为优势种群).结果表明:砂垫层的添加可以有效防止无脊椎动物的穿透,且随着砂垫层高度的增加去除率逐渐升高,轮虫和体长大于200 μm无脊椎动物的去除率分别达46.6%和85.5%,石英砂粒径对轮虫的去除影响较大;砂垫层可以有效去除水中颗粒物,且出水中颗粒数与无脊椎动物丰度显著相关.

  13. Filtration of Carbon Particulate Emissions from a Plasma Pyrolysis Assembly

    Agui, Juan H.; Green, Robert; Vijayakumar, R.; Berger, Gordon; Greenwood, Zach; Abney, Morgan; Peterson, Elspeth

    2016-01-01

    NASA is investigating plasma pyrolysis as a candidate technology that will enable the recovery of hydrogen from the methane produced by the ISS Sabatier Reactor. The Plasma Pyrolysis Assembly (PPA) is the current prototype of this technology which converts the methane product from the Carbon Dioxide Reduction Assembly (CRA) to acetylene and hydrogen with 90% or greater conversion efficiency. A small amount of solid carbon particulates are generated as a side product and must be filtered before the acetylene is removed and the hydrogen-rich gas stream is recycled back to the CRA. We discuss developmental work on several options for filtering out the carbon particulate emissions from the PPA exit gas stream. The filtration technologies and concepts investigated range from fibrous media to monolithic ceramic and sintered metal media. This paper describes the different developed filter prototypes and characterizes their performance from integrated testing at the Environmental Chamber (E-Chamber) at MSFC. In addition, characterization data on the generated carbon particulates, that help to define filter requirements, are also presented.

  14. DOWNFLOW GRANULAR FILTRATION OF ACTIVATED SLUDGE EFFLUENTS

    The performance of downflow granular filters subjected to effluents from activated sludge processes was investigated at the EPA-DC Pilot Plant in Washington, D.C. Several media combinations were investigated, including both single anthracite and dual anthracite-sand configuration...

  15. Submicrometre particle filtration with a dc activated plasma textile

    Plasma textiles are novel fabrics incorporating the advantages of cold plasma and low-cost non-woven or woven textile fabrics. In plasma textiles, electrodes are integrated into the fabric, and a corona discharge is activated within and on the surface of the fabric by applying high voltages above 10 kV between the electrodes. When the plasma textile is activated, submicrometre particles approaching the textile are charged by the deposition of ions and electrons produced by the corona, and then collected by the textile material. A stable plasma discharge was experimentally verified on the surface of the textile that was locally smooth but not rigid. A filtration efficiency close to 100% was observed in experiments conducted on salt particles with diameters ranging from 50 to 300 nm. Unlike conventional fibrous filters, the plasma textile provided uniform filtration in this range, without exhibiting a maximum particle penetration size. (paper)

  16. Active osmotic exchanger for advanced filtration at the nano scale

    Marbach, Sophie; Bocquet, Lyderic

    2015-11-01

    One of the main functions of the kidney is to remove the waste products of an organism, mostly by excreting concentrated urea while reabsorbing water and other molecules. The human kidney is capable of recycling about 200 liters of water per day, at the relatively low cost of 0.5 kJ/L (standard dialysis requiring at least 150 kJ/L). Kidneys are constituted of millions of parallel filtration networks called nephrons. The nephrons of all mammalian kidneys present a specific loop geometry, the Loop of Henle, that is believed to play a key role in the urinary concentrating mechanism. One limb of the loop is permeable to water and the other contains sodium pumps that exchange with a common interstitium. In this work, we take inspiration from this osmotic exchanger design to propose new nanofiltration principles. We first establish simple analytical results to derive general operating principles, based on coupled water permeable pores and osmotic pumps. The best filtration geometry, in terms of power required for a given water recycling ratio, is comparable in many ways to the mammalian nephron. It is not only more efficient than traditional reverse osmosis systems, but can also work at much smaller pressures (of the order of the blood pressure, 0.13 bar, as compared to more than 30 bars for pressure-retarded osmosis systems). We anticipate that our proof of principle will be a starting point for the development of new filtration systems relying on the active osmotic exchanger principle.

  17. Novel antimony doped tin oxide/carbon aerogel as efficient electrocatalytic filtration membrane

    Liu, Zhimeng; Zhu, Mengfu; Wang, Zheng; Wang, Hong; Deng, Cheng; Li, Kui

    2016-05-01

    A facile method was developed to prepare antimony doped tin oxide (Sb-SnO2)/carbon aerogel (CA) for use as an electrocatalytic filtration membrane. The preparation process included synthesis of a precursor sol, impregnation, and thermal decomposition. The Sb-SnO2, which was tetragonal in phase with an average crystallite size of 10.8 nm, was uniformly distributed on the CA surface and firmly attached via carbon-oxygen-tin chemical bonds. Preliminary filtration tests indicated that the Sb-SnO2/CA membrane had a high rate of total organic carbon removal for aqueous tetracycline owing to its high current efficiency and electrode stability.

  18. Water Filtration

    Jacobsen, Erica K.

    2004-01-01

    A water filtration column is devised by students using a two-liter plastic bottle containing gravel, sand, and activated charcoal, to test the filtration potential of the column. Results indicate that the filtration column eliminates many of the contaminating materials, but does not kill bacteria.

  19. Nanoparticle Filtration in a RTM Processed Epoxy/Carbon Fiber Composite

    Miller, Sandi G.; Micham, Logan; Copa, Christine C.; Criss, James M., Jr.; Mintz, Eric A.

    2011-01-01

    Several epoxy matrix composite panels were fabricated by resin transfer molding (RTM) E862/W resin onto a triaxially braided carbon fiber pre-form. Nanoparticles including carbon nanofiber, synthetic clay, and functionalized graphite were dispersed in the E862 matrix, and the extent of particle filtration during processing was characterized. Nanoparticle dispersion in the resin flashing on both the inlet and outlet edges of the panel was compared by TEM. Variation in physical properties such as Tg and moisture absorption throughout the panel were also characterized. All nanoparticle filled panels showed a decrease in Tg along the resin flow path across the panel, indicating nanoparticle filtration, however there was little change in moisture absorption. This works illustrates the need to obtain good nano-particle dispersion in the matrix resin to prevent particle agglomeration and hence particle filtration in the resultant polymer matrix composites (PMC).

  20. Novel antimony doped tin oxide/carbon aerogel as efficient electrocatalytic filtration membrane

    Zhimeng Liu

    2016-05-01

    Full Text Available A facile method was developed to prepare antimony doped tin oxide (Sb-SnO2/carbon aerogel (CA for use as an electrocatalytic filtration membrane. The preparation process included synthesis of a precursor sol, impregnation, and thermal decomposition. The Sb-SnO2, which was tetragonal in phase with an average crystallite size of 10.8 nm, was uniformly distributed on the CA surface and firmly attached via carbon-oxygen-tin chemical bonds. Preliminary filtration tests indicated that the Sb-SnO2/CA membrane had a high rate of total organic carbon removal for aqueous tetracycline owing to its high current efficiency and electrode stability.

  1. Activities of Aureobasidium pullulans cell filtrates against Monilinia laxa of peaches.

    Di Francesco, Alessandra; Roberti, Roberta; Martini, Camilla; Baraldi, Elena; Mari, Marta

    2015-12-01

    The Aureobasidium pullulans L1 and L8 strains are known as efficient biocontrol agents against several postharvest fungal pathogens. In order to better understand the mechanism of action underneath the antifungal activity of L1 and L8 strains, yeast cell filtrates grown at different times were evaluated in vivo against Monilinia laxa on peach. Lesion diameters on peach fruit were reduced by L1 and L8 culture filtrates of 42.5% and 67% respectively. The ability of these filtrates to inhibit M. laxa conidia germination and germ tube elongation was studied by in vitro assays. The results showed a 70% reduction of conidia germination for both strains while for germ tube elongation, it was 52% and 41% for L1 and L8 culture filtrates respectively. Finally, the activity of cell wall hydrolytic enzymes such as chitinase and glucanase in cell filtrates was analysed and the expression of genes encoding these activities was quantified during yeast growth. From 24h onward, both culture filtrates contained β,1-3,glucanase and. chitinase activities, the most pronounced of which was N-β-acetylglucosaminidase. Gene expression level encoding for these enzymes in L1 and L8 varied according to the strain. These results indicate that L1 and L8 strains culture filtrates retain the yeast antagonistic activity and suggest that the production of hydrolytic enzymes plays an important role in this activity. PMID:26640053

  2. Multifunctional nanocomposites of carbon nanotubes and nanoparticles formed via vacuum filtration

    Hersam, Mark C; Ostojic, Gordana; Liang, Yu Teng

    2013-10-22

    In one aspect, the present invention provides a method of forming a film of nanocomposites of carbon nanotubes (CNTs) and platinum (Pt) nanoparticles. In one embodiment, the method includes the steps of (a) providing a first solution that contains a plurality of CNTs, (b) providing a second solution that contains a plurality of Pt nanoparticles, (c) combining the first solution and the second solution to form a third solution, and (d) filtering the third solution through a nanoporous membrane using vacuum filtration to obtain a film of nanocomposites of CNTs and Pt nanoparticles.

  3. Transparent conducting film: Effect of vacuum filtration of carbon nanotube suspended in oleum

    Tsuyoshi Saotome; Hansang Kim; Zhe Wang; David Lashmore; H Thomas Hahn

    2011-07-01

    Vacuum filtration process to fabricate a transparent conducting carbon nanotube (CNT) film is reported. A CNT mat, which is a fibrous sheet of long multi-walled carbon nanotubes (MWNT), was prepared and dispersed in oleum by solution-sonication. The suspension was then vacuum filtered to obtain a thin MWNT layer with improved dispersion. Sheet resistance of the obtained MWNT layer was increased despite the improved dispersion. SEM micrographs and energy dispersive spectroscopy results indicated that the increase of the sheet resistance could be attributed to degradation and oxidation of the MWNT bundles. Though the chemical approach in this study did not improve the electrical property of the CNT mat, a mechanical approach proposed in our recent work was deemed suitable to enhance optical and electrical properties of the CNT mat.

  4. Treatment of heavily contaminated storm water from an industrial site area by filtration through an adsorbent barrier with pine bark (Pinus Silvestris), polonite and active carbon in a comparison study

    Nehrenheim, Emma; Ribé, Veronica; Carlsson, Peter; Eneroth, Peder; Odlare, Monica

    2011-01-01

    This study aims to evaluate a simple and robust filtration method for separation of of heavy metals from storm water. The storm water, collected at a metals manufacturing site, is heavily contaminated with heavy metals, A first analysis of a water sample collected from the site in mid Sweden showed exceptionally high concentrations of especially Zn, which was present in concentrations exceeding 200 mgL-1. The basic idea is to filter the water as it flows out of the industry area through a pas...

  5. Remoção de atrazina e metabólitos pela filtração lenta com leito de areia e carvão ativado granular Removal of atrazine and metabolites through slow filtration by sand and granular activated carbon

    Edumar Ramos Cabral Coelho

    2012-09-01

    Full Text Available A atrazina (ATZé um herbicida largamente utilizado no mundo, sendo encontrada associada aos seus produtos de degradação em águas superficiais e subterrâneas. Pertence à classe das s-triazinas e, juntamente com os metabólitos clorados deetilatrazina (DEA e deisopropilatrazina (DIA, possui potencial carcinogênico e toxicidade como disruptores endócrinos. A limitação dos processos que empregam a coagulação química na remoção de ATZ, a conhecida capacidade do carvão ativado em remover microcontaminantes em água e o risco que a ATZ e seus metabólitos apresentam à saúde motivaram o estudo da filtração lenta com leito de areia e carvão ativado granular. Os resultados apontaram a eficiência do processo de filtração lenta com camada intermediária de carvão ativado granular na remoção de ATZ e a limitação deste na remoção dos metabólitos DEA, DIA e deetilhidroxiatrazina (DEHA.Atrazine (ATZ is widely used as herbicide, commonly found in association to its degradation products in surface water and groundwater. It belongs to the class of s-triazines and together with the chlorinated metabolites dieethylatrazine (DEA and deisopropilatrazine (DIA have carcinogenic potential and toxicity as endocrine disruptors. The limitation of the processes employing chemical coagulation in the removal of atrazine, the known ability of activated carbon to remove microcontaminants in water and the risk that atrazine and the potential toxicity to human health of its metabolits motivated the study of slow sand filtration bed combined with granular activated carbon. The results showed the high efficiency of the slow filtration process with intermediate layer of granular activated carbon in the removal of atrazine and its limitation on the removal of the metabolites DEA, DIA and diethylhidroxiatrazine (DEHA.

  6. Activated carbons and gold

    The literature on activated carbon is reviewed so as to provide a general background with respect to the effect of source material and activation procedure on carbon properties, the structure and chemical nature of the surface of the activated carbon, and the nature of absorption processes on carbon. The various theories on the absorption of gold and silver from cyanide solutions are then reviewed, followed by a discussion of processes for the recovery of gold and silver from cyanide solutions using activated carbon, including a comparison with zinc precipitation

  7. Aberrant glomerular filtration of urokinase-plasminogen activator in nephrotic syndrome leads to amiloride-sensitive plasminogen activation in urine

    Stæhr, Mette; Buhl, Kristian Bergholt; Andersen, René F;

    2015-01-01

    In nephrotic syndrome, aberrant glomerular filtration of plasminogen and conversion to active plasmin in pre-urine is thought to activate proteolytically ENaC and contribute to sodium retention and edema. The ENaC blocker amiloride is an off-target inhibitor of urokinase-type plasminogen activator...

  8. Modern devices of optimum filtration for the active radar system

    V. E. Bychkov

    2006-09-01

    Full Text Available The principle of construction the matched filter and correlator, for the active radar system operating with a broadband noise signal is esteemed. The example of construction a сhan-nel of processing on the basis of microcircuits of a programmed logic (PLD is shown

  9. Pharmaceutically active compounds: Their removal during slow sand filtration and their impact on slow sand filtration bacterial removal.

    D'Alessio, Matteo; Yoneyama, Bunnie; Kirs, Marek; Kisand, Veljo; Ray, Chittaranjan

    2015-08-15

    Slow sand filtration (SSF) has been widely used as a means of providing potable water due to its efficacy, low cost, and minimal maintenance. Advances in analytical instrumentation have revealed the occurrence of pharmaceutically active compounds (PhACs) in surface water as well as in groundwater. It is unclear if the presence of these compounds in the feed water can interfere with the performances of an SSF unit. The aim of this work was to examine i) the ability of two SSF units to remove six PhACs (caffeine, carbamazepine, 17-β estradiol [E2], estrone [E1], gemfibrozil, and phenazone), and ii) the impact of these PhACs on the removal of bacteria by two SSF units. The presence of PhACs in feed water for SSF can occur in surface waters impacted by wastewater or leakage from sewers and septic tanks, as well as in developing countries where unregulated use and improper disposal are prevalent. Two pilot-scale SSF units were used during the study. Unit B1 was fed with stream water with 1% of primary effluent added, while unit B2 was fed with stream water alone. Although limited removal (gemfibrozil, and phenazone occurred, the complete removal of caffeine, and the partial removal (11-92%) of E2 and E1 were observed in the two SSF units. The results of this study suggest that the occurrence of the selected PhACs, probably estrogens and caffeine, in the feed water at 50 μg L(-1) affected the ability of the schmutzdecke to remove total coliform and Escherichia coli. The bacterial removal achieved within the schmutzdecke dropped from 95% to less than 20% by the end of the study. This decrease in removal may be related to the change in the microbial community within the schmutzdecke. A diverse microbial community, including Bacteroidetes and several classes of Proteobacteria, was replaced by a microbial community in which Gammaproteobacteria was the predominant phylum (99%). Despite the low removal achieved within the schmutzdecke, removal of total coliform and E. coli

  10. Light-induced vibration characteristics of free-standing carbon nanotube films fabricated by vacuum filtration

    Li, Junying; Zhu, Yong, E-mail: yongzhu@cqu.edu.cn; Wang, Ning; Zhang, Jie [The Key Laboratory of Optoelectronic Technology and System, Education Ministry of China, Chongqing University, Chongqing, 400044 (China); Wang, Xin [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 (China)

    2014-07-14

    In this paper, we fabricated carbon nanotube (CNT) films with different thickness by vacuum filtration method, and the films were separated from Mixed Cellulose Ester membranes with burn-off process. The thickness of CNT films with different concentrations of CNTs 50 mg, 100 mg, 150 mg, and 200 mg are 10.36 μm, 20.90 μm, 30.19 μm, and 39.98 μm respectively. The CNT bundles are homogeneously distributed and entangled with each other, and still maintain 2D continuous network structures after burn-off process. The optical absorptivity of the films is between 84% and 99% at wavelengths ranging from 400 nm to 2500 nm. Vibration characteristics were measured with the Fabry-Perot (F-P) interferometer vibration measurement system. CNT films vibrate only under the xenon light irradiating perpendicularly to the surface. Vibration recorded by Fabry-Perot interferometer is considered to be caused by the time-dependent thermal moment, which is due to the temperature differences of two sides of CNT films. The vibration frequency spectrums between 0.1 ∼ 0.5 Hz were obtained by the Fast Fourier Transform spectra from time domain to frequency domain, and showed a linear relationship with films thickness, which is in accordance with theoretical model of thermal induced vibration.

  11. Light-induced vibration characteristics of free-standing carbon nanotube films fabricated by vacuum filtration

    In this paper, we fabricated carbon nanotube (CNT) films with different thickness by vacuum filtration method, and the films were separated from Mixed Cellulose Ester membranes with burn-off process. The thickness of CNT films with different concentrations of CNTs 50 mg, 100 mg, 150 mg, and 200 mg are 10.36 μm, 20.90 μm, 30.19 μm, and 39.98 μm respectively. The CNT bundles are homogeneously distributed and entangled with each other, and still maintain 2D continuous network structures after burn-off process. The optical absorptivity of the films is between 84% and 99% at wavelengths ranging from 400 nm to 2500 nm. Vibration characteristics were measured with the Fabry-Perot (F-P) interferometer vibration measurement system. CNT films vibrate only under the xenon light irradiating perpendicularly to the surface. Vibration recorded by Fabry-Perot interferometer is considered to be caused by the time-dependent thermal moment, which is due to the temperature differences of two sides of CNT films. The vibration frequency spectrums between 0.1 ∼ 0.5 Hz were obtained by the Fast Fourier Transform spectra from time domain to frequency domain, and showed a linear relationship with films thickness, which is in accordance with theoretical model of thermal induced vibration.

  12. Pré-tratamento de lixiviados de aterros sanitários por filtração direta ascendente e coluna de carvão ativado Landfill leachate pre-treatment by upflow direct filtration and column of activated carbon

    Armando Borges de Castilhos Junior

    2010-12-01

    Full Text Available Vários problemas ambientais no Brasil decorrem do acelerado crescimento dos setores produtivos e, consequentemente, da multiplicidade dos resíduos sólidos urbanos gerados. A disposição destes em aterros sanitários é prática comum; entretanto, essa deposição requer medidas de proteção ambiental, incluindo o tratamento dos lixiviados. Este trabalho, conduzido em filtros de areia e coluna de carvão ativado, trata de proposta de tratamento físico-químico do lixiviado como alternativa ao processo biológico. No que se refere ao processo de filtração, observaram-se reduções de até 74% para DQO, 47% para DBO, 93% para cor, 90% para amônia e aumento de 0,3 para 0,9 na relação DBO5/DQO. Constataram-se limitações com relação à duração das carreiras de filtração, para o que se sugere avaliar outras granulometrias de areia e até mesmo tecnologias de tratamento.Several environmental problems in Brazil are due to the rapid growth of various productive sectors, and the resulting qualitative multiplicity of municipal solid waste that are generated. The disposal of solid waste in landfills is a common practice; however, it requires environment protection measures, including the treatment of leachate. This work conducted in sand filters and activated carbon column refers to physical and chemical treatment of leachate as an alternative to the biological process. Regarding the filtration process, the results showed reductions of up to 74% for COD, 47% for BOD, 93% for color, 90% for ammonia and an increase from 0.3 to 0.9 in BOD5/COD relation. Limitations were found in relation to filtration run, which suggests the evaluation of other size grains and even treatment technologies.

  13. Influence of adhesion to activated carbon particles on the viability of waterborne pathogenic bacteria under flow

    van der Mei, Henny C.; Atema-Smit, Jelly; Jager, Debbie; Langworthy, Don E.; Collias, Dimitris I.; Mitchell, Michael D.; Busscher, Henk J.

    2008-01-01

    In rural areas around the world, people often rely on water filtration plants using activated carbon particles for safe water supply. Depending on the carbon surface, adhering microorganisms die or grow to form a biofilm. Assays to assess the efficacy of activated carbons in bacterial removal do not

  14. Removal of micropollutants in WWTP effluent by biological assisted membrane carbon filtration (BioMAC).

    Weemaes, M; Fink, G; Lachmund, C; Magdeburg, A; Stalter, D; Thoeye, C; De Gueldre, G; Van De Steene, B

    2011-01-01

    In the frame of the European FP6 project Neptune, a combination of biological activated carbon with ultrafiltration (BioMAC) was investigated for micropollutant, pathogen and ecotoxicity removal. One pilot scale set-up and two lab-scale set-ups, of which in one set-up the granular activated carbon (GAC) was replaced by sand, were followed up during a period of 11 months. It was found that a combination of GAC and ultrafiltration led to an almost complete removal of antibiotics and a high removal (>80%) of most of the investigated acidic pharmaceuticals and iodinated contrast media. The duration of the tests did however not allow to conclude that the biological activation was able to extend the lifetime of the GAC. Furthermore, a significant decrease in estrogenic and anti-androgenic activity could be illustrated. The set-up in which GAC was replaced by sand showed a considerably lower removal efficiency for micropollutants, especially for antibiotics but no influence on steroid activity. PMID:21245556

  15. Preliminary evaluation of fungicidal and termiticidal activities of filtrates from biomass slurry fuel production.

    Kartal, S N; Imamura, Y; Tsuchiya, F; Ohsato, K

    2004-10-01

    Biomass slurry fuel (BSF) production has recently been developed as a natural energy for the conversion of solid biomass into fuel. In addition to using fuel, filtrates from BSF production may also serve a chemical source with several organic compounds. There is an increasing interest in the research and application of biomass-based filtrates. In this study, fungicidal and termiticidal properties of filtrates from BSF production using sugi (Cryptomeria japonica) and acacia (Acacia mangium) wood were evaluated in laboratory decay and termite resistance tests. Wood blocks treated with the filtrates showed increased resistance against brown-rot fungus, Fomitopsis palustris. However the filtrates from sugi wood processed at 270 degrees C which contained less phenolic compounds than the other filtrates were effective against white-rot fungus, Trametes versicolor. Phenolic compounds of filtrates seemed to play a role in the decay resistance tests however the filtrates did not increase the durability of the wood blocks against subterranean termites Coptotermes formosanus. Despite high acetic and lactic acid content of the filtrates, vanillin content of the filtrates may have served as an additional food source and promoted termite attack. It can be concluded that filtrates with phenolic compounds from lignin degradation during BSF production can be considered for targeted inhibition of brown-rot. PMID:15207293

  16. Preliminary evaluation of fungicidal and termiticidal activities of filtrates from biomass slurry fuel production

    Kartal, S.N. [Istanbul University (Turkey). Forestry Faculty; Imamura, Y. [Kyoto University (Japan). Wood Research Institute; Tsuchiya, F.; Ohsato, K. [JGC Corporation, Yokohama (Japan)

    2004-10-01

    Biomass slurry fuel (BSF) production has recently been developed as a natural energy for the conversion of solid biomass into fuel. In addition to using fuel, filtrates from BSF production may also serve a chemical source with several organic compounds. There is an increasing interest in the research and application of biomass-based filtrates. In this study, fungicidal and termiticidal properties of filtrates from BSF production using sugi (Cryptomeria japonica) and acacia (Acacia mangium) wood were evaluated in laboratory decay and termite resistance tests. Wood blocks treated with the filtrates showed increased resistance against brown-rot fungus, Formitopsis palustris. However the filtrates from sugi wood processed at 270{sup o}C which contained less phenolic compounds than the other filtrates were effective against white-rot fungus, Trametes versicolor. Phenolic compounds of filtrates seemed to play a role in the decay resistance tests however the filtrates did not increase the durability of the wood blocks against subterranean termites Coptotermes formosanus. Despite high acetic and lactic acid content of the filtrates, vanillin content of the filtrates may have served as an additional food source and promoted termite attack. It can be concluded that filtrates with phenolic compounds from lignin degradation during BSF production can be considered for targeted inhibition of brown-rot. (author)

  17. Vacuum filtration based formation of liquid crystal films of semiconducting carbon nanotubes and high performance transistor devices

    In this paper, we report ultra-thin liquid crystal films of semiconducting carbon nanotubes using a simple vacuum filtration process. Vacuum filtration of nanotubes in aqueous surfactant solution formed nematic domains on the filter membrane surface and exhibited local ordering. A 2D fast Fourier transform was used to calculate the order parameters from scanning electron microscopy images. The order parameter was observed to be sensitive to the filtration time demonstrating different regions of transformation namely nucleation of nematic domains, nanotube accumulation and large domain growth.Transmittance versus sheet resistance measurements of such films resulted in optical to dc conductivity of σ opt/σ dc = 9.01 indicative of purely semiconducting nanotube liquid crystal network.Thin films of nanotube liquid crystals with order parameters ranging from S = 0.1–0.5 were patterned into conducting channels of transistor devices which showed high I on/I off ratios from 10–19 800 and electron mobility values μ e = 0.3–78.8 cm2 (V-s)−1, hole mobility values μ h = 0.4–287 cm2 (V-s)−1. High I on/I off ratios were observed at low order parameters and film mass. A Schottky barrier transistor model is consistent with the observed transistor characteristics. Electron and hole mobilities were seen to increase with order parameters and carbon nanotube mass fractions. A fundamental tradeoff between decreasing on/off ratio and increasing mobility with increasing nanotube film mass and order parameter is therefore concluded. Increase in order parameters of nanotubes liquid crystals improved the electronic transport properties as witnessed by the increase in σ dc/σ opt values on macroscopic films and high mobilities in microscopic transistors. Liquid crystal networks of semiconducting nanotubes as demonstrated here are simple to fabricate, transparent, scalable and could find wide ranging device applications. (papers)

  18. An integrated dielectrophoresis-active hydrophoretic microchip for continuous particle filtration and separation

    Yan, Sheng; Zhang, Jun; Pan, Chao; Yuan, Dan; Alici, Gursel; Du, Haiping; Zhu, Yonggang; Li, Weihua

    2015-08-01

    Microfluidic manipulation of biological objects from mixture has a significant application in sample preparation and clinical diagnosis. This work presents a dielectrophoresis-active hydrophoretic device for continuous label-free particle separation and filtration. This device comprises interdigitated electrodes and a hydrophoretic channel. According to the difference of lateral positions of polystyrene particles, the device can run at separation or filtration modes by altering the power supply voltages. With an applied voltage of 24 Vp-p, both 3 and 10 μm beads had close lateral positions and were redirected to the same outlet. Under a voltage of 36 Vp-p, beads with the diameters of 3 and 10 μm had different lateral positions and were collected from the different outlets. Separation of 5 and 10 μm particles was achieved to demonstrate the relatively small size difference of the beads. This device has great potential in a range of lab-on-a-chip applications.

  19. Slope filtrations

    André, Yves

    2008-01-01

    Many slope filtrations occur in algebraic geometry, asymptotic analysis, ramification theory, p-adic theories, geometry of numbers... These functorial filtrations, which are indexed by rational (or sometimes real) numbers, have a lot of common properties. We propose a unified abstract treatment of slope filtrations, and survey how new ties between different domains have been woven by dint of deep correspondences between different concrete slope filtrations.

  20. Filtration Fundamentals.

    Ward, Ken; Hunsaker, Scot

    1997-01-01

    Examines how choice of commercial swimming-pool filtration systems is driven by the project-specific needs of the pools. Also highlighted are definitions of specific terms used when discussing filtration systems. Questions that pool designers can answer to make filtration-system purchasing decisions are listed. (GR)

  1. Insecticidal Activity of Ethyl Acetate Extracts from Culture Filtrates of Mangrove Fungal Endophytes.

    Abraham, Silva; Basukriadi, Adi; Pawiroharsono, Suyanto; Sjamsuridzal, Wellyzar

    2015-06-01

    In the search for novel potent fungi-derived bioactive compounds for bioinsecticide applications, crude ethyl acetate culture filtrate extracts from 110 mangrove fungal endophytes were screened for their toxicity. Toxicity tests of all extracts against brine shrimp (Artemia salina) larvae were performed. The extracts with the highest toxicity were further examined for insecticidal activity against Spodoptera litura larvae and acetylcholinesterase (AChE) inhibition activity. The results showed that the extracts of five isolates exhibited the highest toxicity to brine shrimp at 50% lethal concentration (LC50) values of 7.45 to 10.24 ppm. These five fungal isolates that obtained from Rhizophora mucronata were identified based on sequence data analysis of the internal transcribed spacer region of rDNA as Aspergillus oryzae (strain BPPTCC 6036), Emericella nidulans (strains BPPTCC 6035 and BPPTCC 6038), A. tamarii (strain BPPTCC 6037), and A. versicolor (strain BPPTCC 6039). The mean percentage of S. litura larval mortality following topical application of the five extracts ranged from 16.7% to 43.3%. In the AChE inhibition assay, the inhibition rates of the five extracts ranged from 40.7% to 48.9%, while eserine (positive control) had an inhibition rate of 96.8%, at a concentration of 100 ppm. The extracts used were crude extracts, so their potential as sources of AChE inhibition compounds makes them likely candidates as neurotoxins. The high-performance liquid chromatography profiles of the five extracts differed, indicating variations in their chemical constituents. This study highlights the potential of culture filtrate ethyl acetate extracts of mangrove fungal endophytes as a source of new potential bioactive compounds for bioinsecticide applications. PMID:26190921

  2. A comparative study of field emission properties of carbon nanotube films prepared by vacuum filtration and screen-printing

    A comprehensive comparative study of electron field emission properties of carbon nanotube (CNT) films prepared by vacuum filtration and screen-printing was carried out. Field emission performance of vacuum filtered CNT films with different filtered CNT suspension volumes was systematically studied, and the optimum electron emission was obtained with a low turn on field of ∼0.93 V/μm (at 1 μA/cm2) and a high field enhancement factor β of ∼9720. Comparing with screen-printed CNT films, vacuum filtered CNT films showed better electron emission performance, longer lifetime, and greater adhesive strength to substrates. This work reveals a potential use of vacuum filtered CNT films as field emission cathodes.

  3. Dewatering Peat With Activated Carbon

    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.

  4. Upflow Sludge Blanket Filtration (USBF: An Innovative Technology in Activated Sludge Process

    R Saeedi

    2010-06-01

    Full Text Available Background: A new biological domestic wastewater treatment process, which has been presented these days in activated sludge modification, is Upflow Sludge Blanket Filtration (USBF. This process is aerobic and acts by using a sludge blanket in the separator of sedimentation tank. All biological flocs and suspended solids, which are presented in the aeration basin, pas through this blanket. The performance of a single stage USBF process for treatment of domestic wastewater was studied in laboratory scale.Methods: The pilot of USBF has been made from fiberglass and the main electromechanical equipments consisted of an air com­pressor, a mixing device and two pumps for sludge return and wastewater injection. The wastewater samples used for the experiments were prepared synthetically to have qualitative characteristics similar to a typical domestic wastewater (COD= 277 mg/l, BOD5= 250 mg/l and TSS= 1 mg/l.Results: On the average, the treatment system was capable to remove 82.2% of the BOD5 and 85.7% of COD in 6 h hydraulic re­tention time (HRT. At 2 h HRT BOD and COD removal efficiencies dramatically reduced to 50% and 46.5%, respectively.Conclusion: Even by increasing the concentrations of pollutants to as high as 50%, the removal rates of all pollutants were re­mained similar to the HRT of 6 h.

  5. CONVENTIONAL WATER TREATMENT AND DIRECT FILTRATION: TREATMENT AND REMOVAL OF TOTAL ORGANIC CARBON AND TRIHALOMETHANE PRECURSORS

    After describing the fundamentals of coagulation of humic substances for alum and cationic polyelectrolytes, field studies of two conventional-type water treatment plants are discussed. THM formation through the plants is examined, and removals of total organic carbon (TOC) and T...

  6. Characterizing black carbon in rain and ice cores using coupled tangential flow filtration and transmission electron microscopy

    A. Ellis

    2015-06-01

    Full Text Available Antarctic ice cores have been used to study the history of black carbon (BC, but little is known with regards to the physical and chemical characteristics of these particles in the remote atmosphere. Characterization remains limited by ultra-trace concentrations in ice core samples and the lack of adequate methods to isolate the particles unaltered from the melt water. To investigate the physical and chemical characteristics of these particles, we have developed a tangential flow filtration (TFF method combined with transmission electron microscopy (TEM. Tests using ultrapure water and polystyrene latex particle standards resulted in excellent blanks and significant particle recovery. This approach has been applied to melt water from Antarctic ice cores as well as tropical rain from Darwin, Australia with successful results: TEM analysis revealed a variety of BC particle morphologies, insoluble coatings, and the attachment of BC to mineral dust particles. The TFF-based concentration of these particles has proven to give excellent results for TEM studies of BC particles in Antarctic ice cores and can be used for future studies of insoluble aerosols in rainwater and ice core samples.

  7. Multi-walled carbon nanotubes with selected properties for dynamic filtration of pharmaceuticals and personal care products.

    Wang, Yifei; Ma, Jing; Zhu, Jiaxin; Ye, Ning; Zhang, Xiaolei; Huang, Haiou

    2016-04-01

    In this study, multi-walled carbon nanotubes (MWCNT) with selected properties, including pristine MWCNT, hydroxylated MWCNT (H-MWCNT), thin-walled MWCNT with large inner diameter (L-MWCNT), aminated MWCNT, and high-purity MWCNT were investigated for dynamic removal of eight pharmaceuticals and personal care products (PPCP). The removal ratios of different PPCP by the pristine MWCNT followed a decreasing order of triclosan (0.93) > prometryn (0.71) > 4-acetylamino-antipyrine (0.67) > carbendazim (0.65) > caffeine (0.42) > ibuprofen (0.34) > acetaminophen (0.29) at 100 min of filtration. Similar or even higher PPCP removals were obtained for all PPCP as the influent concentration decreased, suggesting potential consistent PPCP removals at environmental PPCP concentrations. The removal ratio of acetaminophen was increased to 0.74 by using H-MWCNT. SRFA (Suwannee River fulvic acid) suppressed PPCP adsorption to MWCNT, to greater extents with increasing SRFA concentrations. The L-MWCNT, despite a large inner diameter of 52 ± 3 nm, did not provide better resistance to the competitive adsorption of SRFA than MWCNT with a small inner diameter of 10 ± 2 nm. Future research will be conducted to minimize the effect of SRFA and facilitate application of MWCNT to the treatment of PPCP-contaminated water. PMID:26845455

  8. Activated carbon for incinerator uses

    This paper reports the development of the activated carbon from palm oil kernel shell for use as absorbent and converter for incinerator gas. The procedure is developed in order to prepare the material in bulk quantity and be used in the incinerator. The effect of the use of activating chemicals, physical activation and the preparation parameter to the quality of the carbon products will be discussed. (Author)

  9. Influence of incubation time of Trichoderma harzianum Rifai and antifungal activity of culture filtrate against Bipolaris oryzae

    Ernesto Juniors Pérez Torres

    2016-03-01

    Full Text Available This work was developed at Agriculture Microbiology laboratory in the Agriculture Faculty at Universidad Central “Martha Abreu” de Las Villas, with the aim to evaluate the influence of incubation time of Trichoderma harzianum Rifai on antifungal activity of its culture filtrates against Bipolaris oryzae. Flask with Czapek broth was used for growing T. harzianum, then one disc of mycelium were incubated during 20 and 30 days at 28±1ºC and dark. Trichoderma harzianum (strain A-34 was submited to filtration process, and comparison were done among concentration of 0%, 25%, 50%, 75%, 100% (v/v. Major inhibition porcentaje were observed in concentrations of 75% y 100% both at 20 and 30 days of incubation. At 20 day the inhibition porcentaje was greater in comparsison with 30 days.

  10. Effect of powdered activated carbon (PAC) and cationic polymer on biofouling mitigation in hybrid MBRs.

    Jamal Khan, S; Visvanathan, C; Jegatheesan, V

    2012-06-01

    In this study, the influence of powdered activated carbon (PAC) and cationic polymer (MPE50) was investigated on the fouling propensity in hybrid MBRs. Three laboratory scale MBRs were operated simultaneously including MBR(Control), MBR(PAC), and MBR(Polymer). Optimum dosages of PAC and polymer to the MBR(PAC) and MBR(Polymer), respectively were determined using jar tests. It was found that the MBR(PAC) exhibited low fouling tendency and prolonged filtration as compared to the other MBRs. Improved filtration in MBR(PAC) was attributed to the flocculation and adsorption phenomena. The effective stability of the biomass by PAC in the form of biological activated carbon (BAC) was verified by the increase in mean particle size. The BAC aided sludge layer exhibited porous cake structure resulting in the prolong filtration. However, both the membrane hybrid systems revealed effective adsorption of organic matter by 40% reduction in the soluble EPS concentration. PMID:22264429

  11. Synthesis of inorganic materials in a supercritical carbon dioxide medium. Application to ceramic cross-flow filtration membranes preparation

    Membrane separations, using cross-flow mineral ceramic membranes, allows fractionation of aqueous solutions due to the molecular sieve effect and electrostatic charges. To obtain a high selectivity, preparation of new selective ceramic membranes is necessary. We propose in this document two different routes to prepare such cross-flow tubular mineral membranes. In the first exposed method, a ceramic material is used, titanium dioxide, synthesized in supercritical carbon dioxide by the hydrolysis of an organometallic precursor of the oxide. The influence of operating parameters is similar to what is observed during a liquid-phase synthesis (sol-gel process), and leads us to control the size and texture of the prepared particles. This material is then used to prepare mineral membrane with a compressed layer process. The particles are mixed with organic components to form a liquid suspension. A layer is then deposited on the internal surface of a tubular porous support by slip-casting. The layer is then dried and compressed on the support before sintering. The obtained membranes arc in the ultrafiltration range. A second process has been developed in this work. It consists on the hydrolysis, in a supercritical CO2 medium, of a precursor of titanium dioxide infiltrated into the support. The obtained material is then both deposited on the support but also infiltrated into the porosity. This new method leads to obtain ultrafiltration membranes that retain molecules which molecular weight is round 4000 g.mol-1. Furthermore, we studied mass transfer mechanisms in cross-flow filtration of aqueous solutions. An electrostatic model, based on generalized Nernst-Planck equation that takes into account electrostatic interactions between solutes and the ceramic material, lead us to obtain a good correlation between experimental results and the numerical simulation. (author)

  12. A Novel Hierarchical Structured Poly(lactic acid/Titania Fibrous Membrane with Excellent Antibacterial Activity and Air Filtration Performance

    Zhe Wang

    2016-01-01

    Full Text Available Hybrid poly(lactic acid/titania (PLA/TiO2 fibrous membranes exhibiting excellent air filtration performance and good antibacterial activity were prepared via the electrospinning technique. By varying the composition of the precursor solutions and the relative humidity, the morphologies of PLA/TiO2 fibers, including the nanopores and nanometer-scale protrusions on the surface of the fibers, could be regulated. The distribution of nanopores and TiO2 nanoparticles on the surface of PLA/TiO2 fibers was investigated. Nitrogen adsorption-desorption analysis revealed that nanopores and nanometer-scale protrusions play an important role in improving the specific surface area and nanopore volume of the relevant PLA/TiO2 fibrous membrane. Filtration performance tests conducted by measuring the penetration of sodium chloride aerosol particles with a 260 nm mass median diameter indicated that fibers with a high surface roughness, large specific surface area, and large nanopore volume greatly improved the particle capture efficiency and facilitated the penetration of airflow. Furthermore, the introduction of TiO2 nanoparticles endows the relevant fibrous membrane with antibacterial properties. The as-prepared PLA/TiO2 fibrous membrane loaded with 1.75 wt% TiO2 nanoparticles formed at a relative humidity of 45% exhibited a high filtration efficiency (99.996% and a relatively low pressure drop (128.7 Pa, as well as a high antibacterial activity of 99.5%.

  13. Aerosol filtration

    Significant developments in high efficiency filtration for nuclear applications are reviewed for the period 1968 to 1980. Topics of special interest include factory (bench) and in-place test methods, new developments in paper and filter unit construction methods, vented containment air cleaning systems for LMFBR and light water moderated reactors, and decontamination of offgases from nuclear waste volume reduction processes. It is noted that standards development has been vigorously pursued during this period but that advances in filtration theory have been few. One of the significant changes likely to occur in the immediate future is adoption of the European style of HEPA filters for those that have been in service for the past three decades to obtain the benefits of having almost twice as much filter paper in the same filter cartridge. 71 references

  14. PROGRESS ON ACTIVATED CARBON FIBERS

    2002-01-01

    Activated carbon fiber is one kind of important adsorption materials. These novel fibrousadsorbents have high specific surface areas or abundant functional groups, which make them havegreater adsorption/desorption rates and larger adsorption capacities than other adsorbents. They canbe prepared as bundle, paper, cloth and felt to meet various technical requirement. They also showreduction property. In this paper the latest progress on the studies of the preparation and adsorptionproperties of activated carbon fibers is reviewed. The application of these materials in drinking waterpurification, environmental control, resource recovery, chemical industry, and in medicine and healthcare is also presented.

  15. ACTIVATION ENERGY OF DESORPTION OF DIBENZOFURAN ON ACTIVATED CARBONS

    LI Xiang; LI Zhong; XI Hongxia; LUO Lingai

    2004-01-01

    Three kinds of commercial activated carbons, such as Norit RB1, Monolith and Chemviron activated carbons, were used as adsorbents for adsorption of dibenzofuran. The average pore size and specific surface area of these activated carbons were measured. Temperature Programmed Desorption (TPD) experiments were conducted to measure the TPD curves of dibenzofuran on the activated carbons, and then the activation energy for desorption of dibenzofuran on the activated carbons was estimated. The results showed that the Chemviron and the Norit RB1 activated carbon maintained higher specific surface area and larger micropore pore volume in comparison with the Monolith activated carbon, and the activation energy for the desorption of dibenzofuran on these two activated carbons was higher than that on the Monolith activated carbon. The smaller the pore of the activated carbon was, the higher the activated energy of dibenzofuran desorption was.

  16. Optimization of membrane bioreactors by the addition of powdered activated carbon.

    Ng, Choon Aun; Sun, Darren; Bashir, Mohammed J K; Wai, Soon Han; Wong, Ling Yong; Nisar, Humaira; Wu, Bing; Fane, Anthony G

    2013-06-01

    It was found that with replenishment, powdered activated carbon (PAC) in the membrane bioreactor (MBR) would develop biologically activated carbon (BAC) which could enhance filtration performance of a conventional MBR. This paper addresses two issues (i) effect of PAC size on MBR (BAC) performance; and (ii) effect of sludge retention time (SRT) on the MBR performance with and without PAC. To interpret the trends, particle/floc size, concentration of mixed liquor suspended solid (MLSS), total organic carbon (TOC), short-term filtration properties and transmembrane pressure (TMP) versus time are measured. The results showed improved fouling control with fine, rather than coarse, PAC provided the flux did not exceed the deposition flux for the fine PAC. Without PAC, the longer SRT operation gave lower fouling at modest fluxes. With PAC addition, the shorter SRT gave better fouling control, possibly due to greater replenishment of the fresh PAC. PMID:23612160

  17. Preparation of very pure active carbon

    The preparation of very pure active carbon is described. Starting from polyvinylidene chloride active carbon is prepared by carbonization in a nitrogen atmosphere, grinding, sieving and activation of the powder fraction with CO2 at 9500 to approximately 50% burn-off. The concentrations of trace and major elements are reduced to the ppb and ppm level, respectively. In the present set-up 100 g of carbon grains and approximately 50 g of active carbon powder can be produced weekly

  18. Improved method for the determination of nonpurgeable suspended organic carbon in natural water by silver filter filtration, wet chemical oxidation, and infrared spectrometry

    Burkhardt, M.R.; Brenton, R.W.; Kammer, J.A.; Jha, V.K.; O'Mara-Lopez, P. G.; Woodworth, M.T.

    1999-01-01

    Precision and accuracy are reported for the first time for the analysis of nonpurgeable suspended organic carbon by silver membrane filtration followed by wet chemical oxidation. A water sample is pressure filtered through a 0.45-??m-pore-size, 47-mm-diameter silver membrane filter. The silver membrane filter then is cut into ribbons and placed in a flame-sealable glass ampule. The organic material trapped on the membrane filter strips is acidified, purged with oxygen to remove inorganic carbonates and volatile organic compounds, and oxidized to carbon dioxide (CO2) using phosphoric acid and potassium persulfate in the sealed glass ampule. The resulting CO2 is measured by a nondispersive infrared CO2 detector. The amount of CO2 is proportional to the concentration of chemically oxidizable nonpurgeable organic carbon in the environmental water sample. The quantitation and method detection limit for routine analysis is 0.2 mg/L. The average percent recovery in five representative matrices was 97 ?? 11%. The errors associated with sampling and sample preparation of nonpurgeable suspended organic carbon are also described.Precision and accuracy are reported for the first time for the analysis of nonpurgeable suspended organic carbon by silver membrane filtration followed by wet chemical oxidation. A water sample is pressure filtered through a 0.45-??m-pore-size, 47-mm-diameter silver membrane filter. The silver membrane filter then is cut into ribbons and placed in a flame-sealable glass ampule. The organic material trapped on the membrane filter strips is acidified, purged with oxygen to remove inorganic carbonates and volatile organic compounds, and oxidized to carbon dioxide (CO2) using phosphoric acid and potassium persulfate in the sealed glass ampule. The resulting CO2 is measured by a nondispersive infrared CO2 detector. The amount of CO2 is proportional to the concentration of chemically oxidizable nonpurgeable organic carbon in the environmental water sample

  19. Aerosol filtration

    This report summarizes the work on the development of fibre metallic prefilters to be placed upstream of HEPA filters for the exhaust gases of nuclear process plants. Investigations at ambient and high temperature were carried out. Measurements of the filtration performance of Bekipor porous webs and sintered mats were performed in the AFLT (aerosol filtration at low temperature) unit with a throughput of 15 m3/h. A parametric study on the influence of particle size, fibre diameter, number of layers and superficial velocity led to the optimum choice of the working parameters. Three selected filter types were then tested with polydisperse aerosols using a candle-type filter configuration or a flat-type filter configuration. The small-diameter candle type is not well suited for a spraying nozzles regeneration system so that only the flat-type filter was retained for high-temperature tests. A high-temperature test unit (AFHT) with a throughput of 8 to 10 m3/h at 4000C was used to test the three filter types with an aerosol generated by high-temperature calcination of a simulated nitric acid waste solution traced with 134Cs. The regeneration of the filter by spray washing and the effect of the regeneration on the filter performance was studied for the three filter types. The porous mats have a higher dust loading capacity than the sintered web which means that their regeneration frequency can be kept lower

  20. Photoconductivity of Activated Carbon Fibers

    Kuriyama, K.; Dresselhaus, M. S.

    1990-08-01

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

  1. Synthesis of Vegetable-Based Activated Carbons with Mixed Micro- and Mesoporosity for Use in Cigarette Filters

    Elizabeth A. Dawson; Parkes, Gareth M. B.; Branton, Peter

    2012-01-01

    Activated carbons with micropores for adsorption and filtration of the volatile constituents of mainstream cigarette smoke, together with mesopores for enhanced mass transport were prepared by a novel route. Treatment of coconut shell or other lignocellulosic precursors with aqueous NaOH, followed by thorough washing, charring and steam activation produced carbons with enhanced adsorption characteristics in smoking trials, compared with their microporous analogues. The mechanism of formation ...

  2. Effect of a biological activated carbon filter on particle counts

    Su-hua WU; Bing-zhi DONG; Tie-jun QIAO; Jin-song ZHANG

    2008-01-01

    Due to the importance of biological safety in drinking water quality and the disadvantages which exist in traditional methods of detecting typical microorganisms such as Cryptosporidium and Giardia,it is necessary to develop an alternative.Particle counts is a qualitative measurement of the amount of dissolved solids in water.The removal rate of particle counts was previously used as an indicator of the effectiveness of a biological activated carbon(BAC)filter in removing Cryptosporidium and Giardia.The particle counts in a BAC filter effluent over one operational period and the effects of BAC filter construction and operational parameters were investigated with a 10 m3/h pilot plant.The results indicated that the maximum particle count in backwash remnant water was as high as 1296 count/ml and it needed about 1.5 h to reduce from the maximum to less than 50 count/ml.During the standard filtration period,particle counts stay constant at less than 50 count/ml for 5 d except when influ-enced by sand filter backwash remnant water.The removal rates of particle counts in the BAC filter are related to characteristics of the carbon.For example,a columned carbon and a sand bed removed 33.3% and 8.5% of particles,respectively,while the particle counts in effluent from a cracked BAC filter was higher than that of the influent.There is no significant difference among particle removal rates with different filtration rates.High post-ozone dosage(>2 mg/L)plays an important role in particle count removal;when the dosage was 3 mg/L,the removal rates by carbon layers and sand beds decreased by 17.5% and increased by 9.5%,respectively,compared with a 2 mg/L dosage.

  3. Influence of organic carbon loading, sediment associated metal oxide content and sediment grain size distributions upon Cryptosporidium parvum removal during riverbank filtration operations, Sonoma County, CA

    Metge, D.W.; Harvey, R.W.; Aiken, G.R.; Anders, R.; Lincoln, G.; Jasperse, J.

    2010-01-01

    This study assessed the efficacy for removing Cryptosporidium parvum oocysts of poorly sorted, Fe- and Al-rich, subsurface sediments collected from 0.9 to 4.9 and 1.7-13.9??m below land surface at an operating riverbank filtration (RBF) site (Russian River, Sonoma County, CA). Both formaldehyde-killed oocysts and oocyst-sized (3????m) microspheres were employed in sediment-packed flow-through and static columns. The degree of surface coverage of metal oxides on sediment grain surfaces correlated strongly with the degrees of oocyst and microsphere removals. In contrast, average grain size (D50) was not a good indicator of either microsphere or oocyst removal, suggesting that the primary mechanism of immobilization within these sediments is sorptive filtration rather than physical straining. A low specific UV absorbance (SUVA) for organic matter isolated from the Russian River, suggested that the modest concentration of the SUVA component (0.8??mg??L-1) of the 2.2??mg??L-1 dissolved organic carbon (DOC) is relatively unreactive. Nevertheless, an amendment of 2.2??mg??L-1 of isolated river DOC to column sediments resulted in up to a 35.7% decrease in sorption of oocysts and (or) oocyst-sized microspheres. Amendments (3.2????M) of the anionic surfactant, sodium dodecyl benzene sulfonate (SDBS) also caused substantive decreases (up to 31.9 times) in colloid filtration. Although the grain-surface metal oxides were found to have a high colloid-removal capacity, our study suggested that any major changes within the watershed that would result in long-term alterations in either the quantity and (or) the character of the river's DOC could alter the effectiveness of pathogen removal during RBF operations.

  4. 臭氧/陶瓷膜对生物活性炭工艺性能和微生物群落结构影响%Influence of ozone/ceramic membrane on performance and microbial community in biological activated carbon filtration

    郭建宁; 陈磊; 张锡辉; 王凌云; 陶益; 盛德洋

    2014-01-01

    Micro-polluted raw water was treated using a pilot plant with a scale of 120m3/d. The performance of ozone/ceramic membrane-biological activated carbon (BAC) process was studied. The diversity and detailed structure of microbial community of the microorganisms in BAC were also investigated. The hybrid process removed organic matter and ammonia effectively. The aeration with ozone-containing gas increased the dissolved oxygen in water flow and improved the removal of ammonia. The total removal efficiencies of ammonia and CODMn were 90% and 84%, respectively. The BAC played an important role in the final removals of pollutants. The microorganisms in the BAC bed were divided into 36phyla. Compared with the conventional BAC process, ozone/ceramic membrane in the hybrid process decreased the diversity and evenness of the microorganisms in the BAC. There were abundant Nitrosomonas and Nitrospira in the BAC in the hybrid process, which probably strengthen the ammonia removal. Moreover, the pathogenic bacteria and opportunistic pathogen were significantly inhibited by ozone/ceramic membrane, resulting in the decrease of their relative abundances in the following BAC. Therefore the biological safety of drinking water was enhanced significantly.%利用处理量为120m3/d的臭氧/陶瓷膜-生物活性炭(BAC)组合工艺处理微污染原水,对工艺性能和BAC中的微生物多样性和种群结构进行了研究。结果显示,组合工艺可有效去除微污染原水中的有机物和氨氮。臭氧曝气提高了溶解氧浓度,改善了后续 BAC 工艺对氨氮的去除效果。组合工艺对氨氮和CODMn的总去除率分别约为90%和84%,其中BAC在污染物的去除中发挥了重要作用。组合工艺和传统工艺中BAC床层共检测到36个门类的细菌。与传统BAC工艺相比,臭氧/陶瓷膜降低了后续BAC中微生物群落结构的多样性和均匀度。组合工艺BAC中存在丰度较高的亚硝化单胞菌属和硝化螺旋

  5. Volumetric and superficial characterization of carbon activated

    The activated carbon is the resultant material of the calcination process of natural carbonated materials as coconut shells or olive little bones. It is an excellent adsorbent of diluted substances, so much in colloidal form, as in particles form. Those substances are attracted and retained by the carbon surface. In this work is make the volumetric and superficial characterization of activated carbon treated thermically (300 Centigrade) in function of the grain size average. (Author)

  6. Comparison of membrane fouling during short-term filtration of aerobic granular sludge and activated sludge

    2007-01-01

    Aerobic granular sludge was cultivated adopting internal-circulate sequencing batch airlift reactor. The contradistinctive experiment about short-term membrane fouling between aerobic granular sludge system and activated sludge system were investigated. The membrane foulants was also characterized by Fourier Transform Infrared (FTIR) spectroscopy technique. The results showed that the aerobic granular sludge had excellent denitrification ability; the removal efficiency of TN could reach 90%. The aerobic granular sludge could alleviate membrane fouling effectively. The steady membrane flux of aerobic granular sludge was twice as much as that of activated sludge system. In addition, it was found that the aerobic granular sludge could result in severe membrane pore-blocking, however, the activated sludge could cause severe cake fouling. The major components of the foulants were identified as comprising of proteins and polysaccharide materials.

  7. Adsorption of Imidacloprid on Powdered Activated Carbon and Magnetic Activated Carbon

    Zahoor, M.; Mahramanlioglu, M.

    2011-01-01

    The adsorptive characteristics of imidacloprid on magnetic activated carbon (MAC12) in comparison to powdered activated carbon (PAC) were investigated. Adsorption of imidacloprid onto powdered activated carbon and magnetic activated carbon was studied as a function of time, initial imidacloprid concentration, temperature and pH. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models for both carbons were used to describe the kinetic data. The adsorption equilibrium data we...

  8. Nanostructural activated carbons for hydrogen storage

    Li, Suoding

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

  9. Measurement of carbon thermodynamic activity in sodium

    The report presents the brief outline on system of carbon activity detecting system in sodium (SCD), operating on the carbon-permeable membrane, of the methods and the results of testing it under the experimental circulating loop conditions. The results of carbon activity sensor calibration with the use of equilibrium samples of XI8H9, Fe -8Ni, Fe -12Mn materials are listed. The behaviour of carbon activity sensor signals in sodium under various transitional conditions and hydrodynamic perturbation in the circulating loop, containing carbon bearing impurities in the sodium flow and their deposits on the surfaces flushed by sodium, are described. (author)

  10. Evaluation of the plasma quality after filtration

    M Mahmoodian Shooshtari

    2010-06-01

    Full Text Available "n  "n "nBackground and the purpose of the study: The quality of some of the human plasma derived drugs such as coagulation factor VIII and coagulation factor IX which can be used for the treatment of hemophilia A and B, depends on their activity which may be affected by filtration. In this study the quality of plasma with respect to coagulation factors FVII, FVIII, FIX, FV, FXI, Fibrinogen, antithrombin III, anti-plasmin and antitrypsin activities obtained after plasma filtration with CPD (citrate-phosphate-dextrose using integral filter was evaluated. "nMethods:Sixty units of plasma were individually separated from whole blood by centrifugation and immediately filtered by integral filter system. Specific plasma filtration was carried out between 4 and 20 hrs after blood donation. Before filtration, 60 units of non filtered fresh plasmas were kept as control. "nCoagulation factors were determined by one-stage clotting assay in an automated system. Antithrombin III activity was determined by immunochrom assay in an automated system. Activity of anti-plasmin was determined by Berichrom α2 - antiplasmin and antitrypsin activity was assayed with human neutrophil elastase. "n  "nResults:The activity of coagulation factors FVIII, FIX, Fibrinogen, FV, and FXI, were not affected by filtration, in all experiments. Filtration only caused negligible change in FVII activity. Antithrombin III, anti-plasmin and antitrypsin activities were not influenced by filtration. Non-filtrated and filtrated plasma values were not significantly different (P> 0.05. Conclusions:Plasma filtration dose not result in a measurable impairment of coagulation factors and inhibitors. Although a little changes in FVII activity was observed after filtration, but these filtration-dependent changes apparently have no impact on the therapeutic quality of whole blood- filtered fresh plasma for transfusion.

  11. The effect of feed water dissolved organic carbon concentration and composition on organic micropollutant removal and microbial diversity in soil columns simulating river bank filtration.

    Bertelkamp, C; van der Hoek, J P; Schoutteten, K; Hulpiau, L; Vanhaecke, L; Vanden Bussche, J; Cabo, A J; Callewaert, C; Boon, N; Löwenberg, J; Singhal, N; Verliefde, A R D

    2016-02-01

    This study investigated organic micropollutant (OMP) biodegradation rates in laboratory-scale soil columns simulating river bank filtration (RBF) processes. The dosed OMP mixture consisted of 11 pharmaceuticals, 6 herbicides, 2 insecticides and 1 solvent. Columns were filled with soil from a RBF site and were fed with four different organic carbon fractions (hydrophilic, hydrophobic, transphilic and river water organic matter (RWOM)). Additionally, the effect of a short-term OMP/dissolved organic carbon (DOC) shock-load (e.g. quadrupling the OMP concentrations and doubling the DOC concentration) on OMP biodegradation rates was investigated to assess the resilience of RBF systems. The results obtained in this study imply that - in contrast to what is observed for managed aquifer recharge systems operating on wastewater effluent - OMP biodegradation rates are not affected by the type of organic carbon fraction fed to the soil column, in case of stable operation. No effect of a short-term DOC shock-load on OMP biodegradation rates between the different organic carbon fractions was observed. This means that the RBF site simulated in this study is resilient towards transient higher DOC concentrations in the river water. However, a temporary OMP shock-load affected OMP biodegradation rates observed for the columns fed with the river water organic matter (RWOM) and the hydrophilic fraction of the river water organic matter. These different biodegradation rates did not correlate with any of the parameters investigated in this study (cellular adenosine triphosphate (cATP), DOC removal, specific ultraviolet absorbance (SUVA), richness/evenness of the soil microbial population or OMP category (hydrophobicity/charge). PMID:26432535

  12. Studies of activated carbon and carbon black for supercapacitor applications

    Richner, R.; Mueller, S.; Koetz, R.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Carbon Black and activated carbon materials providing high surface areas and a distinct pore distribution are prime materials for supercapacitor applications at frequencies < 0.5 Hz. A number of these materials were tested for their specific capacitance, surface and pore size distribution. High capacitance electrodes were manufactured on the laboratory scale with attention to ease of processability. (author) 1 fig., 1 ref.

  13. Methane storage in a commercial activated carbon.

    K. Wang

    2008-06-01

    Full Text Available A commercial activated carbon was examined for possible methane storage application. The structural and surface propertiesof the carbon were characterized by Nitrogen adsorption isotherm at 77 oK. It was found that the carbon is largelymicroporous with a surface area of approximately 860 m2/g. Adsorption test shows the carbon is able to achieve a methanestorage capacity of approximately 70/cc.

  14. Spherical carbons: Synthesis, characterization and activation processes

    Romero Anaya, Aroldo José; Ouzzine, Mohammed; Lillo Ródenas, María Ángeles; Linares Solano, Ángel

    2014-01-01

    Spherical carbons have been prepared through hydrothermal treatment of three carbohydrates (glucose, saccharose and cellulose). Preparation variables such as treatment time, treatment temperature and concentration of carbohydrate have been analyzed to obtain spherical carbons. These spherical carbons can be prepared with particle sizes larger than 10 μm, especially from saccharose, and have subsequently been activated using different activation processes (H3PO4, NaOH, KOH or physical activati...

  15. Preparation of activated carbon by chemical activation under vacuum.

    Juan, Yang; Ke-Qiang, Qiu

    2009-05-01

    Activated carbons especially used for gaseous adsorption were prepared from Chinesefir sawdust by zinc chloride activation under vacuum condition. The micropore structure, adsorption properties, and surface morphology of activated carbons obtained under atmosphere and vacuum were investigated. The prepared activated carbons were characterized by SEM, FTIR, and nitrogen adsorption. It was found that the structure of the starting material is kept after activation. The activated carbon prepared under vacuum exhibited higher values of the BET surface area (up to 1079 m2 g(-1)) and total pore volume (up to 0.5665 cm3 g(-1)) than those of the activated carbon obtained under atmosphere. This was attributed to the effect of vacuum condition that reduces oxygen in the system and limits the secondary reaction of the organic vapor. The prepared activated carbon has well-developed microstructure and high microporosity. According to the data obtained, Chinese fir sawdust is a suitable precursor for activated carbon preparation. The obtained activated carbon could be used as a low-cost adsorbent with favorable surface properties. Compared with the traditional chemical activation, vacuum condition demands less energy consumption, simultaneity, and biomass-oil is collected in the procedure more conveniently. FTIR analysis showed that heat treatment would result in the aromatization of the carbon structure. PMID:19534162

  16. Adsorption of organic substances to activated carbon

    Adsorption systems using activated carbon as an almost universal adsorbent for organic substances are widely applied for purifying exhaust air. The possibilities, limits and measures for an optimum design of activated carbon processes are given from the point of view of the plant designed and under the aspects of the present laws for environmental control. (orig.)

  17. Preparation and characterisation of activated carbon

    Activated carbon was prepared from Agricultural wastes, such as coconut shell, Palm oil Shell and mangrove trunk by destructive distillation under vakuum. Chemical and Physical properties of the activated carbon were studied and some potentially useful application in the fields of chemistry was also carried out

  18. Laundry wastewater treatment using coagulation and membrane filtration

    Šostar-Turk, Sonja; Petrinić, Irena; Simonič, Marjana

    2012-01-01

    This paper presents the results obtained from laundry wastewater treatment using conventional methods namely precipitation/coagulation and the flocculation process with adsorption on granular-activated carbon (GAC) and an alternative method, membrane filtrations, namely ultrafiltration (UF) and reverse osmosis (RO). Chemical analyses showed that parameter values of untreated wastewater like temperature, pH, sediment substances, total nitrogen and phosphorous, COD, BOD5, and the amount of anio...

  19. Calcium carbonate phosphate binding ion exchange filtration and accelerated denitrification improve public health standards and combat eutrophication in aquatic ecosystems.

    Yanamadala, Vijay

    2005-01-01

    Cultural eutrophication, the process by which a lake becomes rich in dissolved nutrients as a result of point and nonpoint pollutant sources, is a major cause of the loss of natural lake ecosystems throughout the world. The process occurs naturally in all lakes, but phosphate-rich nutrient runoff from sources such as storm drains and agricultural runoff is a major cause of excess phosphate-induced eutrophication. Especially in Madrona Marsh, one of the last remaining vernal marshes in the greater Los Angeles area, California, cultural eutrophication has become a major problem. In this study, calcium carbonate was found to be an excellent phosphate binder, reducing up to 70% of the phosphates in a given sample of water, and it posed relatively negligent ecological repercussions. This study involved the testing of this principle in both the laboratory and the real ecosystem. A calcium carbonate lacing procedure was first carried out to determine its efficacy in Madrona Marsh. Through this, ammonia was found to interfere with the solubility of calcium carbonate and therefore to be a hindrance to the reduction of phosphate. Therefore, various approaches for reduction of ammonia were tested, including aeration, use of fiber growth media, and plants, mainly Caulerpa verticellata, chosen for it hardiness, primarily in an attempt to increase population of Nitrobacter and Nitrosomonas. All were successful in moderately reducing ammonia levels. In addition, soil sampling, sediment analysis, microscopic plant analysis, microorganism and macroinvertebrate identification, and rate law formulations were conducted. The effect of phosphate and ammonia reduction on the populations of enterobacteria was also an important focus of this experiment. Varying concentrations of phosphate, ammonia, and calcium carbonate in conjunction with phosphate were tested in Madrona Marsh to determine their effects on the populations of enteropathogens on nonspecific blood agar, MacConkey agar, and

  20. Effect of Vitamin D Receptor Activators on Glomerular Filtration Rate: A Meta-Analysis and Systematic Review.

    Qian Zhang

    Full Text Available Vitamin D receptor activators (VDRAs can protect against mineral bone disease, but they are reported to elevate serum creatinine (SCr and may also reduce glomerular filtration rate (GFR.We conducted a systematic review and meta-analysis of randomized clinical trials (RCTs to evaluate the effect of VDRAs on kidney function and adverse events. MEDLINE, EMBASE, the Cochrane Controlled Trials Register were searched for RCTs that evaluate vitamin D receptor activators (alfacalcidol, calcitriol, doxercalciferol, falecalcitriol, maxacalcitol and paricalcitol up to March 2015.We included 31 studies, all of which were performed between 1976 and 2015, which enrolled 2621 patients. Patients receiving VDRAs had lower eGFR (weighted mean difference WMD -1.29 mL/min /1.73 m2, 95% CI -2.42 to -0.17 and elevated serum creatinine (WMD 7.03 μmol/L, 95% CI 0.61 to 13.46 in sensitivity analysis excluding studies with dropout rate more than 30%. Subgroup analysis of the 5 studies that not use SCr-based measures did not indicated lower GFR in the VDRAs group(WMD -0.97 mL/min/1.73 m2, 95% CI -4.85 to 2.92. Compared with control groups, there was no difference in all-cause mortality (relative risk RR 1.41, 95% CI 0.58 to 3.80, cardiovascular disease (RR 0.84, 95% CI 0.42 to 1.71, and severe adverse events (RR 1.15, 95% CI 0.75 to 1.77 for the VDRAs groups. Episodes of hypercalcemia (RR 3.29, 95% CI 2.02 to 5.38 were more common in the VDRAs group than in the control group.Administration of VDRAs increased serum creatinine levels. Subgroup analysis of studies that did not use SCr-based measures did not indicate a lower GFR in the VDRA group. Future studies with non-SCr-based measures are needed to assess whether the mild elevations of serum creatinine are of clinical significance.

  1. Ozonation and activated carbon treatment of sewage effluents: removal of endocrine activity and cytotoxicity.

    Stalter, Daniel; Magdeburg, Axel; Wagner, Martin; Oehlmann, Jörg

    2011-01-01

    Concerns about endocrine disrupting compounds in sewage treatment plant (STP) effluents give rise to the implementation of advanced treatment steps for the elimination of trace organic contaminants. The present study investigated the effects of ozonation (O(3)) and activated carbon treatment (AC) on endocrine activities [estrogenicity, anti-estrogenicity, androgenicity, anti-androgenicity, aryl-hydrocarbon receptor (AhR) agonistic activity] with yeast-based bioassays. To evaluate the removal of non-specific toxicity, a cytotoxicity assay using a rat cell line was applied. Wastewater (WW) was sampled at two STPs after conventional activated sludge treatment following the secondary clarifier (SC) and after subsequent advanced treatments: O(3), O(3) + sand filtration (O(3-SF)), and AC. Conventional treatment reduced estrogenicity, androgenicity, and AhR agonistic activity by 78-99% compared to the untreated influent WW. Anti-androgenicity and anti-estrogenicity were not detectable in the influent but appeared in SC, possibly due to the more effective removal of respective agonists during conventional treatment. Endocrine activities after SC ranged from 2.0 to 2.8 ng/L estradiol equivalents (estrogenicity), from 4 to 22 μg/L 4-hydroxytamoxifen equivalents (anti-estrogenicity), from 1.9 to 2.0 ng/L testosterone equivalents (androgenicity), from 302 to 614 μg/L flutamide equivalents (anti-androgenicity), and from 387 to 741 ng/L β-naphthoflavone equivalents (AhR agonistic activity). In particular, estrogenicity and anti-androgenicity occurred in environmentally relevant concentrations. O(3) and AC further reduced endocrine activities effectively (estrogenicity: 77-99%, anti-androgenicity: 63-96%, AhR agonistic activity: 79-82%). The cytotoxicity assay exhibited a 32% removal of non-specific toxicity after O(3) compared to SC. O(3) and sand filtration reduced cytotoxic effects by 49%, indicating that sand filtration contributes to the removal of toxicants. AC was the

  2. The investigation of copper-based impregnated activated carbons prepared from water-soluble materials for broad spectrum respirator applications

    The preparation of impregnated activated carbons (IACs) from aqueous, copper-containing solutions for broad spectrum gas filtration applications is studied here. Several samples were studied to determine the effect that impregnant loading, impregnant distribution and impregnant recipe had on the overall performance. Dynamic flow testing was used to determine the gas filtration capacity of the IAC samples versus a variety of challenge gases. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were used to characterize the impregnant distribution on the carbon as a function of impregnant loading. Oven tests were performed to determine the thermal stability of the IAC samples exposed to elevated temperatures. The role impregnant distribution plays in gas filtration capacity and the overall performance of the IAC samples is discussed. The IAC samples prepared in this work were found to have gas filtration capacities as good as or better than broad spectrum respirator carbon samples prepared from the patent literature. IACs impregnated with an aqueous 2.4 M Cu(NO3)2/0.04 M H3PO4.12MoO3/4 M HNO3 solution that were heated to 200 deg. C under argon were found to have the best overall performance of the samples studied in this work.

  3. The investigation of copper-based impregnated activated carbons prepared from water-soluble materials for broad spectrum respirator applications

    Smith, J.W.H.; Westreich, P.; Abdellatif, H.; Filbee-Dexter, P.; Smith, A.J. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H 3J5 (Canada); Wood, T.E. [3M Company, St. Paul, MN, 55144 (United States); Croll, L.M.; Reynolds, J.H. [3M Canada Company, Brockville, Ontario, K6V 5V8 (Canada); Dahn, J.R., E-mail: jeff.dahn@dal.ca [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H 3J5 (Canada); Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, B3H 4J3 (Canada)

    2010-08-15

    The preparation of impregnated activated carbons (IACs) from aqueous, copper-containing solutions for broad spectrum gas filtration applications is studied here. Several samples were studied to determine the effect that impregnant loading, impregnant distribution and impregnant recipe had on the overall performance. Dynamic flow testing was used to determine the gas filtration capacity of the IAC samples versus a variety of challenge gases. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were used to characterize the impregnant distribution on the carbon as a function of impregnant loading. Oven tests were performed to determine the thermal stability of the IAC samples exposed to elevated temperatures. The role impregnant distribution plays in gas filtration capacity and the overall performance of the IAC samples is discussed. The IAC samples prepared in this work were found to have gas filtration capacities as good as or better than broad spectrum respirator carbon samples prepared from the patent literature. IACs impregnated with an aqueous 2.4 M Cu(NO{sub 3}){sub 2}/0.04 M H{sub 3}PO{sub 4}.12MoO{sub 3}/4 M HNO{sub 3} solution that were heated to 200 deg. C under argon were found to have the best overall performance of the samples studied in this work.

  4. Multiplug filtration clean-up with multiwalled carbon nanotubes in the analysis of pesticide residues using LC-ESI-MS/MS.

    Zhao, Pengyue; Fan, Sufang; Yu, Chuanshan; Zhang, Junyan; Pan, Canping

    2013-10-01

    A novel design for a rapid clean-up method was developed for the analysis of pesticide residues in fruit and vegetables followed by LC-ESI-MS/MS. The acetonitrile-based sample extraction technique was used to obtain the extracts, and further clean-up was carried out by applying the streamlined procedure on a multiplug filtration clean-up column coupled with a syringe. The sorbent used for clean-up in this research is multiwalled carbon nanotubes, which was mixed with anhydrous magnesium sulfate to remove water from the extracts. This method was validated on 40 representative pesticides and apple, cabbage, and potato sample matrices spiked at two concentration levels of 10 and 100 μg/kg. It exhibited recoveries between 71 and 117% for most pesticides with RSDs 0.995 for most studied pesticides between concentration levels of 10-500 μg/L. The LOQs for 40 pesticides ranged from 2 to 50 μg/kg. The developed method was successfully applied to the determination of pesticide residues in market fruit and vegetable samples. PMID:23939876

  5. Pathogen filtration to control plant disease outbreak in greenhouse production

    Jeon, Sangho; Krasnow, Charles; Bhalsod, Gemini; Granke, Leah; Harlan, Blair; Hausbeck, Mary; Zhang, Wei

    2016-04-01

    Previous research has been extensively focused on understanding the fate and transport of human microbial pathogens in soil and water environments. However, little is known about the transport of plant pathogens, although these pathogens are often found in irrigation waters and could cause severe crop damage and economical loss. Water mold pathogens including Phytophthora spp. and Pythium spp. are infective to a wide range of vegetable and floriculture crops, and they are primarily harbored in soils and disseminated through water flow. It is challenging to control these pathogens because they often quickly develop resistance to many fungicides. Therefore, this multi-scale study aimed to investigate physical removal of plant pathogens from water by filtration, thus reducing the pathogen exposure risks to crops. In column-scale experiments, we studied controlling factors on the transport and retention of Phytophthora capsici zoospores in saturated columns packed with iron oxide coated-sand and uncoated-sand under varying solution chemistry. Biflagellate zoospores were less retained than encysted zoospores, and lower solution pH and greater iron oxide content increased the retention of encysted zoospores. These results provided insights on environmental dispersal of Phytophthora zoospores in natural soils as well as on developing cost-effective engineered filtration systems for pathogen removal. Using small-scale greenhouse filtration systems, we further investigated the performance of varying filter media (i.e., granular sand, iron oxide coated ceramic porous media, and activated carbon) in mitigating disease outbreaks of Phytophthora and Pythium for greenhouse-grown squash and poinsettia, respectively, in comparison with fungicide treatment. For squash, filtration by iron oxide coated media was more effective in reducing the Phytophthora infection, comparing to sand filtration and fungicide application. For poinsettia, sand filtration performed better in controlling

  6. Diesel fuel filtration system

    The American nuclear utility industry is subject to tight regulations on the quality of diesel fuel that is stored at nuclear generating stations. This fuel is required to supply safety-related emergency diesel generators--the backup power systems associated with the safe shutdown of reactors. One important parameter being regulated is the level of particulate contamination in the diesel fuel. Carbon particulate is a natural byproduct of aging diesel fuel. Carbon particulate precipitates from the fuel's hydrocarbons, then remains suspended or settles to the bottom of fuel oil storage tanks. If the carbon particulate is not removed, unacceptable levels of particulate contamination will eventually occur. The oil must be discarded or filtered. Having an outside contractor come to the plant to filter the diesel fuel can be costly and time consuming. Time is an even more critical factor if a nuclear plant is in a Limiting Condition of Operation (LCO) situation. A most effective way to reduce both cost and risk is for a utility to build and install its own diesel fuel filtration system. The cost savings associated with designing, fabricating and operating the system inhouse can be significant, and the value of reducing the risk of reactor shutdown because of uncertified diesel fuel may be even higher. This article describes such a fuel filtering system

  7. ACTIVATED CARBON FROM LIGNITE FOR WATER TREATMENT

    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

  8. Rotary filtration system

    Herman, David T.; Maxwell, David N.

    2011-04-19

    A rotary filtration apparatus for filtering a feed fluid into permeate is provided. The rotary filtration apparatus includes a container that has a feed fluid inlet. A shaft is at least partially disposed in the container and has a passageway for the transport of permeate. A disk stack made of a plurality of filtration disks is mounted onto the shaft so that rotation of the shaft causes rotation of the filtration disks. The filtration disks may be made of steel components and may be welded together. The shaft may penetrate a filtering section of the container at a single location. The rotary filtration apparatus may also incorporate a bellows seal to prevent leakage along the shaft, and an around the shaft union rotary joint to allow for removal of permeate. Various components of the rotary filtration apparatus may be removed as a single assembly.

  9. Activation of Carbon Dioxide and Synthesis of Propylene Carbonate

    2002-01-01

    Cycloaddition of carbon dioxide and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine (TBA) shows higher yield than catalyzed by unsubstituted metal phthalocyanine. Comparing different catalysts of diverse metals, (t-Bu)4PcMg is more active than (t-Bu)4PcFe. But (t-Bu)4PcCo and (t-Bu)4PcNi only have low catalytic activities towards the reaction. Moreover, the yield will increase as the temperature increases.

  10. ESTIMATION OF ACTIVATED ENERGY OF DESORPTION OF n-HEXANE ON ACTIVATED CARBONS BY TPD TECHNIQUE

    2001-01-01

    In this paper, six kinds of activated carbons such as Ag+-activated carbon, Cu2+-activated carbon, Fe3+- activated carbon, activated carbon, Ba2+- activated carbon and Ca2+-activated carbon were prepared. The model for estimating activated energy of desorption was established. Temperature-programmed desorption (TPD) experiments were conducted to measure the TPD curves of n-hexanol and then estimate the activation energy for desorption of n-hexanol on the activated carbons. Results showed that the activation energy for the desorption of n-hexanol on the Ag+- activated carbon, the Cu2+- activated carbon and the Fe3+- activated carbon were higher than those of n-hexanol on the activated carbon, the Ca2+- activated carbon and the Ba2+- activated carbon.

  11. ESTIMATION OF ACTIVATED ENERGY OF DESORPTION OF n—HEXANE ON ACTIVATED CARBONS BY PTD TECHNIQUE

    LIZhong; WANGHongjuan; 等

    2001-01-01

    In this paper,six kinds of activated carbons such as Ag+-activated carbon,Cu2+activated carbon,Fe3+-activated carbon,activated carbon,Ba2+-activated carbon and Ca2+activated carbon were prepared.The model for estimating activated energy of desorption was established.Temperature-programmed desorption(TPD)experiments were conducted to measure the TPD curves of n-hexanol and then estimate the activation energy for desorption of n-hexanol on the activated carbons.Results showed that the activation energy for the desorption of n-hexanol on the Ag+-activated carbon,the Cu2+-activated carbon and the Fe3+-activated carbon were higher than those of n-hexanol on the activated carbon,the Ca2+-activated carbon and the Ba2+-activated carbon.

  12. Investigation of Microgranular Adsorptive Filtration System

    Cai, Zhenxiao

    Over the past few decades, enormous advances have been made in the application of low-pressure membrane filtration to both drinking water and wastewater treatment. Nevertheless, the full potential of this technology has not been reached, due primarily to limitations imposed by membrane fouling. In drinking water treatment, much of the fouling is caused by soluble and particulate natural organic matter (NOM). Efforts to overcome the problem have focused on removal of NOM from the feed solution, usually by addition of conventional coagulants like alum and ferric chloride (FeCl3) or adsorbents like powdered activated carbon (PAC). While coagulants and adsorbents can remove a portion of the NOM, their performance with respect to fouling control has been inconsistent, often reducing fouling but sometimes having no effect or even exacerbating fouling. This research investigated microgranular adsorptive filtration (muGAF), a process that combines three existing technologies---granular media filtration, packed bed adsorption, and membrane filtration---in a novel way to reduce membrane fouling while simultaneously removing NOM from water. In this technology, a thin layer of micron-sized adsorbent particles is deposited on the membrane prior to delivering the feed to the system. The research reported here represents the first systematic study of muGAF, and the results demonstrate the promising potential of this process. A new, aluminum-oxide-based adsorbent---heated aluminum oxide particles (HAOPs)---was synthesized and shown to be very effective for NOM removal as well as fouling reduction in muGAF systems. muGAF has also been demonstrated to work well with powdered activated carbon (PAC) as the adsorbent, but not as well as when HAOPs are used; the process has also been successful when used with several different membrane types and configurations. Experiments using a wide range of operational parameters and several analytical tools lead to the conclusion that the fouling

  13. Activated Carbons From Grape Seeds By Chemical Activation With Potassium Carbonate And Potassium Hydroxide

    Okman, Irem; Karagöz, Selhan; Tay, Turgay; Erdem, Murat

    2014-02-01

    Activated carbons were produced from grape seed using either potassium carbonate (K2CO3) or potassium hydroxide (KOH). The carbonization experiments were accomplished at 600 and 800 °C. The effects of the experimental conditions (i.e., type of activation reagents, reagent concentrations, and carbonization temperatures) on the yields and the properties of these activated carbons were analyzed under identical conditions. An increase in the temperature at the same concentrations for both K2CO3 and KOH led to a decrease in the yields of the activated carbons. The lowest activated carbon yields were obtained at 800 °C at the highest reagent concentration (100 wt%) for both K2CO3 and KOH. The activated carbon with the highest surface area of 1238 m2g-1 was obtained at 800 °C in K2CO3 concentration of 50 wt% while KOH produced the activated carbon with the highest surface area of 1222 m2g-1 in a concentration of 25wt% at 800 °C. The obtained activated carbons were mainly microporous.

  14. Carbon Activation Diagnostic for Tertiary Neutron Measurements

    Glebov, V.Yu.; Stoeckl, C.; Sangster, T.C.; Meyerhofer, D.D.; Radha, P.B.; Padalino, S.; Baumgart, L.; Fuschino, J.

    2003-03-28

    OAK B202 The yield of tertiary neutrons with energies greater than 20 MeV has been proposed to determine the high rho R of inertial confinement fusion targets. The activation of carbon is a valuable measurement technique because of its high reaction threshold, the availability of high-purity samples, and relatively low cost. The 12C(n,2n)11C reaction has a Q value of 18.7 MeV, well above the 14.1 MeV primary DT neutron energy. The isotope 11C decays with a half-life of 20.3 min and emits a positron, resulting in the production of two back-to-back, 511 keV gamma rays upon annihilation. The positron decay of 11C is nearly identical to the copper decay used in the activation measurements of 14.1 MeV primary DT yields; therefore, the present copper activation gamma-detection system can be used to detect the tertiary-produced carbon activation. Because the tertiary neutron yield is more than six orders of magnitude lower than primary neutron yield, the carbon activation diagnostic requires ultrapure carbon samples, free from any positron-emitting contamination. In recent years we have developed carbon purification, packaging, and handling procedures that minimize the contamination signal to a level low enough to use carbon activation for tertiary neutron measurements in direct-drive implosion experiments with DT cryogenic targets on OMEGA. Experimental results of contamination measurements in carbon samples performed on high-neutron-yield shots on OMEGA in 2001-2002 will be presented. A concept for implementing a carbon activation system on the National Ignition Facility (NIF)will be discussed.

  15. PREPARATION OF MESOPOROUS CARBON BY CARBON DIOXIDE ACTIVATION WITH CATALYST

    W.Z.Shen; A.H.Lu; J.T.Zheng

    2002-01-01

    A mesoporous activated carbon (AC) can be successfully prepared by catalytic activa-tion with carbon dioxide. For iron oxide as catalyst, there were two regions of mesoporesize distribution, i.e. 2-5nm and 30-70nm. When copper oxide or magnesium oxidecoexisted with iron oxide as composite catalyst, the content of pores with sizes of 2-5nm was decreased, while the pores with 30 70nm were increased significantly. Forcomparison, AC reactivated by carbon dioxide directly was also investigated. It wasshown that the size of mesopores of the resulting AC concentrated in 2-5nm with lessvolume. The adsorption of Congo red was tested to evaluate the property of the result-ing AC. Furthermore, the factors affecting pore size distribution and the possibility ofmesopore formation were discussed.

  16. Organic solvent regeneration of granular activated carbon

    Cross, W. H.; Suidan, M. T.; Roller, M. A.; Kim, B. R.; Gould, J. P.

    1982-09-01

    The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to thermal regeneration. The important aspects of the solvent regeneration process include: the physical and chemical characteristics of the adsorbent, the pore size distribution and energy of adsorption associated with the activated carbon; the degree of solubility of the adsorbate in the organic solvent; the miscibility of the organic solvent in water; and the temperature at which the generation is performed.

  17. Visualization of water flow during filtration using flat filtration materials

    Hrůza Jakub; Šidlof Petr; Bílek Petr

    2012-01-01

    Filtration materials are very important elements of some industrial appliances. Water filtration is a separation of solid materials from fluid. Solid particles are captured on the frontal area of the filtration textile and only liquid passes through it. It is important to know the filtration process in a detailed way to be able to develop filtration materials. Visualization of filtration process enables a better view of the filtration. This method also enables to determine efficiency and homo...

  18. Microwave-assisted regeneration of activated carbon.

    Foo, K Y; Hameed, B H

    2012-09-01

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

  19. Antimicrobial Activity of Carbon-Based Nanoparticles

    Solmaz Maleki Dizaj

    2015-03-01

    Full Text Available 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.

  20. Activated coconut shell charcoal carbon using chemical-physical activation

    Budi, Esmar; Umiatin, Nasbey, Hadi; Bintoro, Ridho Akbar; Wulandari, Futri; Erlina

    2016-02-01

    The use of activated carbon from natural material such as coconut shell charcoal as metal absorbance of the wastewater is a new trend. The activation of coconut shell charcoal carbon by using chemical-physical activation has been investigated. Coconut shell was pyrolized in kiln at temperature about 75 - 150 °C for about 6 hours in producing charcoal. The charcoal as the sample was shieved into milimeter sized granule particle and chemically activated by immersing in various concentration of HCl, H3PO4, KOH and NaOH solutions. The samples then was physically activated using horizontal furnace at 400°C for 1 hours in argon gas environment with flow rate of 200 kg/m3. The surface morphology and carbon content of activated carbon were characterized by using SEM/EDS. The result shows that the pores of activated carbon are openned wider as the chemical activator concentration is increased due to an excessive chemical attack. However, the pores tend to be closed as further increasing in chemical activator concentration due to carbon collapsing.

  1. Importance of the colmation layer in the transport and removal of cyanobacteria, viruses, and dissolved organic carbon during natural lake-bank filtration

    Harvey, Ronald W.; Metge, David W.; LeBlanc, Denis R.; Underwood, Jennifer C.; Aiken, George R.; Butler, Kenna; McCobb, Timothy D.; Jasperse, Jay

    2015-01-01

    This study focused on the importance of the colmation layer in the removal of cyanobacteria, viruses, and dissolved organic carbon (DOC) during natural bank filtration. Injection-and-recovery studies were performed at two shallow (0.5 m deep), sandy, near-shore sites at the southern end of Ashumet Pond, a waste-impacted, kettle pond on Cape Cod, MA, that is subject to periodic blooms of cyanobacteria and continuously recharges a sole-source drinking-water aquifer. The experiment involved assessing the transport behaviors of bromide (conservative tracer), Synechococcus sp. IU625 (cyanobacterium, 2.6 ± 0.2 µm), AS-1 (tailed cyanophage, 110 nm long), MS2 (coliphage, 26 nm diameter), and carboxylate-modified microspheres (1.7 µm diameter) introduced to the colmation layer using a bag-and-barrel (Lee-type) seepage meter. The injectate constituents were tracked as they were advected across the pond water–groundwater interface and through the underlying aquifer sediments under natural-gradient conditions past push-point samplers placed at ∼30-cm intervals along a 1.2-m-long, diagonally downward flow path. More than 99% of the microspheres, IU625, MS2, AS-1, and ∼44% of the pond DOC were removed in the colmation layer (upper 25 cm of poorly sorted bottom sediments) at two test locations characterized by dissimilar seepage rates (1.7 vs. 0.26 m d−1). Retention profiles in recovered core material indicated that >82% of the attached IU625 were in the top 3 cm of bottom sediments. The colmation layer was also responsible for rapid changes in the character of the DOC and was more effective (by three orders of magnitude) at removing microspheres than was the underlying 20-cm-thick segment of sediment.

  2. Effect of low dosages of powdered activated carbon on membrane bioreactor performance.

    Remy, Maxime; Temmink, Hardy; Rulkens, Wim

    2012-01-01

    Previous research has demonstrated that powdered activated carbon (PAC), when applied at very low dosages and long SRTs, reduces membrane fouling in membrane bioreactors (MBRs). This effect was related to the formation of stronger sludge flocs, which are less sensitive to shear. In this contribution the long-term effect of PAC addition was studied by running two parallel MBRs on sewage. To one of these, PAC was dosed and a lower fouling tendency of the sludge was verified, with a 70% longer sustainable filtration time. Low PAC dosages showed additional advantages with regard to oxygen transfer and dewaterability, which may provide savings on operational costs. PMID:22339033

  3. Benefit-cost analysis of commercially available activated carbon filters for indoor ozone removal in single-family homes.

    Aldred, J R; Darling, E; Morrison, G; Siegel, J; Corsi, R L

    2016-06-01

    This study involved the development of a model for evaluating the potential costs and benefits of ozone control by activated carbon filtration in single-family homes. The modeling effort included the prediction of indoor ozone with and without activated carbon filtration in the HVAC system. As one application, the model was used to predict benefit-to-cost ratios for single-family homes in 12 American cities in five different climate zones. Health benefits were evaluated using disability-adjusted life-years and included city-specific age demographics for each simulation. Costs of commercially available activated carbon filters included capital cost differences when compared to conventional HVAC filters of similar particle removal efficiency, energy penalties due to additional pressure drop, and regional utility rates. The average indoor ozone removal effectiveness ranged from 4 to 20% across the 12 target cities and was largely limited by HVAC system operation time. For the parameters selected in this study, the mean predicted benefit-to-cost ratios for 1-inch filters were >1.0 in 10 of the 12 cities. The benefits of residential activated carbon filters were greatest in cities with high seasonal ozone and HVAC usage, suggesting the importance of targeting such conditions for activated carbon filter applications. PMID:25952610

  4. Production of activated carbons from almond shell

    Nabais, Joao M. Valente; Laginhas, Carlos Eduardo C.; Carrott, P.J.M.; Ribeiro Carrott, M.M.L. [Evora Univ. (Portugal). Centro de Quimica de Evora

    2011-02-15

    The production of activated carbons from almond shell, using physical activation by CO{sub 2} is reported in this work. The used method has produced activated carbons with apparent BET surface areas and micropore volume as high as 1138 m{sup 2} g{sup -1} and 0.49 cm{sup 3} g{sup -1}, respectively. The activated carbons produced have essentially primary micropores and only a small volume of wider micropores. By FTIR analysis it was possible to identify, in the surface of the activated carbons, several functional groups, namely hydroxyls (free and phenol), ethers, esters, lactones, pyrones and Si-H bonds. By the analysis of the XRD patterns it was possible to calculate the microcrystallites dimensions with height between 1.178 and 1.881 nm and width between 3.106 and 5.917 nm. From the XRD it was also possible to identify the presence of traces of inorganic heteroatoms such as Si, Pb, K, Fe and P. All activated carbons showed basic characteristics with point of zero charge between 9.42 and 10.43. (author)

  5. Refining of hydrochars/ hydrothermally carbonized biomass into activated carbons and their applications

    Hao, Wenming

    2014-01-01

    Hydrothermally treated biomass could not only be used as a fuel or a fertilizer but it can also be refined into high-value products. Activated carbons are one of those. In the studies of this thesis, four different hydrothermally carbonized (HTC) biomasses, including horse manure, grass cuttings, beer waste and biosludge, have been successfully made into activated carbons. The activated carbon materials were in the forms of powdered activated carbons, powdered composites of activated carbon a...

  6. Two-stage anaerobic membrane bioreactor for the treatment of sugarcane vinasse: assessment on biological activity and filtration performance.

    Mota, Vera Tainá; Santos, Fábio S; Amaral, Míriam C S

    2013-10-01

    A two-stage submerged anaerobic membrane bioreactor (2-SAnMBR) was designed for the treatment of sugarcane vinasse. For start-up, the flow rate was reduced whenever VFA levels reached critical levels in the methanogenic reactor. After acclimation, the system was operated under a continuous flow. Separation of the stages was observed during the entire period of operation. VFA, COD and DOC levels of raw effluent, acidified effluent and permeate averaged 2141, 3525 and 61 mg VFA L(-1) (as acetic acid), 15727, 11512 and 488 mg COD L(-1), and, 3544, 3533 and 178 mg DOC L(-1), respectively. Overall COD and DOC removal efficiencies of 96.9±0.7% and 95.0±1.1%, respectively, were reached. Methane content of the biogas from the acidogenic and methanogenic reactors ranged 0.1-4.6% and 60.1-70.1%, respectively. Removable fouling strongly affected filtration performance and cake layer formation accounted for most of filtration resistance. Membrane resistance was related to presence of protein-like substances and carbohydrates. PMID:23958682

  7. Adsorptive removal of nitrilotris(methylenephosphonic acid) antiscalant from membrane concentrates by iron-coated waste filtration sand.

    Boels, L; Tervahauta, T; Witkamp, G J

    2010-10-15

    Iron-coated waste filtration sand was investigated as a low-cost adsorbent for the removal of nitrilotris(methylenephosphonic acid) (NTMP) from membrane concentrates. The adsorption of this phosphonate-based antiscalant on this material was measured and compared with two commercially available anion exchange resins and activated carbon. Comprehensive adsorption experiments were conducted in several synthetic concentrate solutions and in a concentrate collected from a full scale nano-filtration brackish water desalination plant. The effect of pH, ionic strength and the presence of competitive anions on the equilibrium adsorption were investigated. The results showed that, in contrast to the anion exchange resins, the adsorption on coated filtration sand is not suppressed at increasing ionic strength and is much less affected by the competitive anions carbonate and sulphate. The adsorption decreased slightly when the pH was raised from 7.0 to 8.0. The adsorption isotherms in the real nano-filtration concentrate, measured in the concentration interval of 5-50 mg dm(-1) NTMP, showed that the maximum adsorption capacity of coated filtration sand was 4.06 mg g(-1). The adsorption capacity per unit mass of the adsorbents at low NTMP concentration (12.5 mg dm(-3)) followed the decreasing order Amberlite IRA-410>coated filtration sand>Amberlite IRA-900>Norit SAE Super. This demonstrates that the use of iron-coated waste filtration sand offers a promising means for the removal of NTMP from membrane concentrates. PMID:20667427

  8. Ignition properties of nuclear grade activated carbons

    The ignition property of new activated carbons used in air cleaning systems of nuclear facilities has been evaluated in the past, however very little information has been generated on the behavior of aged, weathered carbons which have been exposed to normal nuclear facility environment. Additionally the standard procedure for evaluation of ignition temperature of carbon is performed under very different conditions than those used in the design of nuclear air cleaning systems. Data were generated evaluating the ageing of activated carbons and comparing their CH3131I removal histories to their ignition temperatures. A series of tests were performed on samples from one nuclear power reactor versus use time, a second series evaluated samples from several plants showing the variability of atmospheric effects. The ignition temperatures were evaluated simulating the conditions existing in nuclear air cleaning systems, such as velocity, bed depth, etc., to eliminate potential confusion resulting from artifically set current standard conditions

  9. PREPARATION OF ACTIVATED CARBON FROM PEAT

    Yasumitsu Uraki

    2009-02-01

    Full Text Available Peat with an approximate 60% carbon content collected in the suburbs of Palangka Raya, Indonesia, was carbonized, followed by activation with steam in an electric furnace. The resultant activated carbon (AC had ca. 900 m2/g of BET surface area and 1000 mg/g of iodine adsorption. This performance implies that this AC can be used as an adsorbent for environmental purification. We had a carbonizing furnace manufactured in Palangka Raya, which did not require electric power. Some AC having 350 mg/g of iodine adsorption was obtained by using this furnace. Although the adsorption ability was much lower than that of commercially available AC, the AC achieved significant decoloration and decrease in chemical oxygen demand of polluted river water. Thus, this article demonstrated the potential of tropical peat soil as a source of AC.

  10. Dynamic adsorption of radon on activated carbon

    The adsorption of 222Rn from air onto activated carbon was studied over the range 0 to 550C. A sharp pulse of radon was injected into an air stream that flowed through a bed of activated carbon. The radon concentration in the exit from the column was continuously monitored using a zinc sulfide α-scintillation flow cell. Elution curves were analyzed to determine the dynamic adsorption coefficient and the number of theoretical stages. Five types of activated carbon were tested and the dynamic adsorption coefficient was found to increase linearly with surface area in the range 1000 to 1300 m2g-1. The adsorptive capacity of activated carbon was reduced by up to 30% if the entering gas was saturated with water vapor and the bed was initially dry. If the bed was allowed to equilibrate with saturated air, the adsorptive capacity was too low to be of practical use. The minimum height equivalent to a theoretical stage (HETS) was about four times the particle diameter and occurred at superficial velocities within the range 0.002 to 0.02 m s-1. For superficial velocities above 0.05 m s-1, the HETS was determined by the rate of mass transfer. The application of these results to the design of activated carbon systems for radon retention is discussed

  11. Microcystin-LR Adsorption by Activated Carbon.

    Pendleton, Phillip; Schumann, Russell; Wong, Shiaw Hui

    2001-08-01

    We use a selection of wood-based and coconut-based activated carbons to investigate the factors controlling the removal of the hepatotoxin microcystin-LR (m-LR) from aqueous solutions. The wood carbons contain both micropores and mesopores. The coconut carbons contain micropores only. Confirming previously published observations, we also find that the wood-based carbons adsorb more microcystin than the coconut-based carbons. From a combination of a judicious modification of a wood-based carbon's surface chemistry and of the solution chemistry, we demonstrate that both surface and solution chemistry play minor roles in the adsorption process, with the adsorbent surface chemistry exhibiting less influence than the solution chemistry. Conformational changes at low solution pH probably contribute to the observed increase in adsorption by both classes of adsorbent. At the solution pH of 2.5, the coconut-based carbons exhibit a 400% increased affinity for m-LR compared with 100% increases for the wood-based carbons. In an analysis of the thermodynamics of adsorption, using multiple temperature adsorption chromatography methods, we indicate that m-LR adsorption is an entropy-driven process for each of the carbons, except the most hydrophilic and mesoporous carbon, B1. In this case, exothermic enthalpy contributions to adsorption also exist. From our overall observations, since m-LR contains molecular dimensions in the secondary micropore width range, we demonstrate that it is important to consider both the secondary micropore and the mesopore volumes for the adsorption of m-LR from aqueous solutions. Copyright 2001 Academic Press. PMID:11446779

  12. The effect of filter cake viscoelasticity on filtration

    Christensen, Morten Lykkegaard

    difficult to use the existing mathematical filtration models to simulate and optimise the filtration process. Activated sludge as well as synthetic model particles has been filtrated in this project. The study shows that compression of the formed filter cake is a time dependent process, and not only a...

  13. Evaluation of Wastewater Filtration

    Benth, Bryant L.; Middlebrooks, E. Joe; George, Dennis B.; Reynolds, James H.

    1981-01-01

    Tertiary filtration of secondary wastewater is frequently used to improve wastewater treatment plant effluent quality. Four experimental filter columns were operated at the Preston, Idaho, Wastewater Treatment Plant to evaluate the effectiveness of granular media, gravity filtration. The Preston plant is a trickling filter secondary treatment plant and services a population of approximately 3600 people. Four filt...

  14. Activated carbon monoliths for methane storage

    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. USING POWDERED ACTIVATED CARBON: A CRITICAL REVIEW

    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...

  16. MODELING MERCURY CONTROL WITH POWDERED ACTIVATED CARBON

    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...

  17. Uranium removal from water using cellulose triacetate membranes added with activated carbon

    Villalobos-Rodriguez, R. [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, Compl. Ind. Chihuahua, CP 31109, Chihuahua, Chih. (Mexico); Montero-Cabrera, M.E., E-mail: elena.montero@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, Compl. Ind. Chihuahua, CP 31109, Chihuahua, Chih. (Mexico); Esparza-Ponce, H.E.; Herrera-Peraza, E.F. [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, Compl. Ind. Chihuahua, CP 31109, Chihuahua, Chih. (Mexico); Ballinas-Casarrubias, M.L. [Facultad de Ciencias Quimicas, Universidad Autonoma de Chihuahua, Nuevo Campus s/n, Chihuahua, Chih. (Mexico)

    2012-05-15

    Ultrafiltration removal of uranium from water, with composite activated carbon cellulose triacetate membranes (AC-CTA), was investigated. The filtrate was provided by uraninite dissolution with pH=6-8. Removal efficiencies were calculated measuring solutions' radioactivities. Membranes were mainly characterized by microscopy analysis, revealing iron after permeation. Uranyl removal was 35{+-}7%. Chemical speciation indicates the presence of (UO{sub 2}){sub 2}CO{sub 3}(OH){sub 3}{sup -}, UO{sub 2}CO{sub 3}, UO{sub 2}(CO{sub 3}){sub 2}{sup 2-} and Fe{sub 2}O{sub 3}(s) as main compounds in the dissolution, suggesting co-adsorption of uranium and iron by the AC during filtration, as the leading rejection path. - Highlights: Black-Right-Pointing-Pointer Cellulose triacetate (CTA) and activated carbon (AC) composite membranes were suitable for uranium removal. Black-Right-Pointing-Pointer Up to 35% of uranium from low concentrated solutions was rejected by ultrafiltration. Black-Right-Pointing-Pointer Rejection is performed by a hybrid mechanism regulated by AC adsorption. Black-Right-Pointing-Pointer Uranium and iron speciation and predominance determines the adsorption in the membrane.

  18. Uranium removal from water using cellulose triacetate membranes added with activated carbon

    Ultrafiltration removal of uranium from water, with composite activated carbon cellulose triacetate membranes (AC-CTA), was investigated. The filtrate was provided by uraninite dissolution with pH=6–8. Removal efficiencies were calculated measuring solutions' radioactivities. Membranes were mainly characterized by microscopy analysis, revealing iron after permeation. Uranyl removal was 35±7%. Chemical speciation indicates the presence of (UO2)2CO3(OH)3−, UO2CO3, UO2(CO3)22− and Fe2O3(s) as main compounds in the dissolution, suggesting co-adsorption of uranium and iron by the AC during filtration, as the leading rejection path. - Highlights: ► Cellulose triacetate (CTA) and activated carbon (AC) composite membranes were suitable for uranium removal. ► Up to 35% of uranium from low concentrated solutions was rejected by ultrafiltration. ► Rejection is performed by a hybrid mechanism regulated by AC adsorption. ► Uranium and iron speciation and predominance determines the adsorption in the membrane.

  19. Magnetic-seeding filtration

    Magnetic-seeding filtration consists of two steps: heterogeneous particle flocculation of magnetic and nonmagnetic particles in a stirred tank and high-gradient magnetic filtration (HGMF). The effects of various parameters affecting magnetic-seeding filtration (HGMF). The effects of various parameters affecting magnetic seeding filtration are theoretically and experimentally investigated. A trajectory model that includes hydrodynamic resistance, van der Waals, and electrostatic forces is developed to calculate the flocculation frequency in a turbulent-shear regime. Fractal dimension is introduced to simulate the open structure of aggregates. A magnetic-filtration model that consists of trajectory analysis, a particle build-up model, a breakthrough model, and a bivariate population-balance model is developed to predict the breakthrough curve of magnetic-seeding filtration. A good agreement between modeling results and experimental data is obtained. The results show that the model developed in this study can be used to predict the performance of magnetic-seeding filtration without using empirical coefficients or fitting parameters. 35 refs., 7 figs., 1 tab

  20. A study on the consecutive preparation of silica powders and active carbon from rice husk ash

    Rice husk ash (RHA) is an abundant agricultural by-product. The present research work deals with the production of silica powders and active carbon from RHA with a consecutive method. The RHA is firstly treated with acid leaching to remove mineral composition, and then is boiled with base to leach silica. The filtrate is used to synthesize silica powders with CO2 precipitator and solid residue is used to prepare active carbon. The optimum conditions of preparing silica powders are as follows: the concentration of Na2CO3 is 25 wt.%, the base-leached time is 4 h, and the impregnation ratio of Na2CO3 solution to RHA is 6:1. The yield of silica leached from RHA is 84.57 wt.%. The synthesized silica powders are hydrated with amorphous structure, moreover, with a relative smooth surface and high purity. The residue is activated with potassium hydroxide (KOH) after base-leached. The activated carbons are found to be a mixture of micropore and mesopore pore structures. The maximum pore volume, BET surface area and iodine adsorption capacity of as-prepared active carbon can reach 1.22 cm3/g, 1936.62 m2/g and 1259.06 mg/g, respectively. Field emission scanning electron microscopy (SEM) is used to characterize the morphological features of the ash after step by step treatment.

  1. 76 FR 67142 - Certain Activated Carbon From the People's Republic of China: Final Results and Partial...

    2011-10-31

    ... Administrative Review, 75 FR 48644 (August 11, 2010) (``First Rescission''). \\5\\ See Certain Activated Carbon... activated carbon is a powdered, granular, or pelletized carbon product obtained by ``activating'' with heat... activated carbon, including powdered activated carbon (``PAC''), granular......

  2. Device for determining carbon activity through pressure

    A hollow iron capsule of annular shape having an interior layer of Fe0.947O and a near absolute internal vacuum is submersed within a molten metal with the inner chamber of the capsule connected to a pressure sensor. Carbon present in the molten metal diffuses through the capsule wall and reacts with the Fe0.947O layer to generate a CO2--CO gas mixture within the internal chamber. The total absolute pressure of the gas measured by the pressure sensor is directly proportional to the carbon activity of the molten metal

  3. The association of vanadium with the iron transport system in human blood as determined by gel filtration and neutron activation analysis

    Although vanadium has a suspected physiological role in man, the existing data available on its metabolism at molecular level are very limited and inadequate for modern toxicological and nutritional evaluations. To study its metabolic patterns in the human body it is necessary to determine the association with different biochemical components. The paper describes the identification of V-binding components in human blood by means of fractionation of human serum proteins and neutron activation analysis of the protein fractions of different molecular weight. Since information on the chemical form of V in blood is not well known, preliminary radiotracer experiments were performed by injecting 48V into rats and successively fractionating the 48V plasma proteins by gel filtration, ion-exchange chromatography and poliacrylamide gel electrophoresis. The results indicated that V in rat blood was mainly present in the serum as a V-transferrin biocomplex. It seemed reasonable to assume that a similar biocomplex could also be present in the blood of human subjects. To confirm on man the results obtained by 48V experiments on rats, human plasma proteins were isolated and separated by gel filtration on Sephadex resin and the V content in the elution fractions was determined by neutron activation followed by a rapid radiochemical separation of the induced 52V and gamma-ray spectrometry using a Ge(Li) detector. The results show that V in human plasma was effectively associated with transferrin protein, the iron transport system of the blood. A brief discussion of the results and of the determination of metal-binding components in the human body by combining biochemical techniques and neutron activation analysis is also given (author)

  4. Filtration characteristics in membrane bioreactors

    Evenblij, H.

    2006-01-01

    Causes of and remedies for membrane fouling in Membrane Bioreactors for wastewater treatment are only poorly understood and described in scientific literature. A Filtration Characterisation Installation and a measurement protocol were developed with the aim of a) unequivocally determination and quantification of the filterability of an activated sludge and b) carrying out short term experiments at labscale to determine foulants and/or fouling propensity determining factors. The installation w...

  5. Supercapacitor Electrodes from Activated Carbon Monoliths and Carbon Nanotubes

    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. Filtration in Porous Media

    Yuan, Hao; Shapiro, Alexander

    There is a considerable and ongoing effort aimed at understanding the transport and the deposition of suspended particles in porous media, especially non-Fickian transport and non-exponential deposition of particles. In this work, the influential parameters in filtration models are studied to...... understand their effects on the non-Fickian transport and the non-exponential deposition. The filtration models are validated by the comparisons between the modelling results and the experimental data.The elliptic equation with distributed filtration coefficients may be applied to model non-Fickian transport...... and hyperexponential deposition. The filtration model accounting for the migration of surface associated particles may be applied for non-monotonic deposition....

  7. Voltammetric Response of Epinephrine at Carbon Nanotube Modified Glassy Carbon Electrode and Activated Glassy Carbon Electrode

    WANG Juan; TANG Ping; ZHAO Fa-qiong; ZENG Bai-zhao

    2005-01-01

    The electrochemical behavior of epinephrine at activated glassy carbon electrode and carbon nanotube-coated glassy carbon electrode was studied. Epinephrine could exhibit an anodic peak at about 0.2 V (vs. SCE) at bare glassy carbon electrode, but it was very small.However, when the electrode was activated at certain potential (i. e. 1.9V) or modified with carbon nanotube, the peak became more sensitive,resulting from the increase in electrode area in addition to the electrostatic attraction. Under the selected conditions, the anodic peak current was linear to epinephrine concentration in the range of 3.3 × 10-7-1.1 × 10-5mol/L at activated glassy carbon electrode and in the range of 1.0 × 10-6-5.0 × 10-5 mol/L at carbon nanotube-coated electrode. The correlation coefficients were 0. 998 and 0. 997, respectively. The determination limit was 1.0 × 10-7 mol/L. The two electrodes have been successfully applied for the determination of epinephrine in adrenaline hydrochloride injection with recovery of 95%-104%.

  8. Active carbons from low temperature conversion chars

    Hulls obtained from the fruits of five tropical biomass have been subjected to low temperature conversion process and their chars activated by partial physical gasification to produce active carbons. The biomass are T. catappa, B. nitida, L leucophylla, D. regia and O. martiana. The bulk densities of the samples ranged from 0.32 g.cm3 to 0.52 g.cm3. Out of the samples T. catappa recorded the highest cellulose content (41.9 g.100g-1), while O. martiana contained the highest lignin content (40.7 g.100g-1). The ash of the samples were low (0.5 - 4.4%). The percentage of char obtained after conversion were high (33.7% - 38.6%). Active carbons obtained from T. catappa, D. regia and O. martiana, recorded high methylene blue numbers and iodine values. They also displayed good micro- and mesostructural characteristics. Micropore volume (Vmicro) was between 0.33cm3.g-1 - 0.40cm3.g-1, while the mesopore volume(Vmeso) was between 0.05 cm3.g-1 - 0.07 cm3.g-1. The BET specific surface exceeds 1000 m2.g-1. All these values compared favourably with high grade commercial active carbons. (author)

  9. Pilot plant study on ozonation and biological activated carbon process for drinking water treatment

    2006-01-01

    A study on advanced drinking water treatment was conducted in a pilot scale plant taking water from conventional treatment process. Ozonation-biological activated carbon process (O3-BAC) and granular activated carbon process (GAC) were evaluated based on the following parameters: CODMn, UV254, total organic carbon (TOC), assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC). In this test, the average removal rates of CODMn , UV254 and TOC in O3-BAC were18.2%, 9.0% and 10.2% higher on (AOC) than in GAC, respectively. Ozonation increased 19.3-57.6 μg Acetate-C/L in AOC-P17,45.6-130.6 μg Acetate-C/L in AOC-NOX and 0.1-0.5 mg/L in BDOC with ozone doses of 2-8 mg/L. The optimum ozone dose for maximum AOC formation was 3 mgO3/L. BAC filtration was effective process to improve biostability.

  10. Filtration aids in uranium ore processing

    A process of improving the filtration efficiency and separation of uranium ore pulps obtained by carbonate leaching of uranium ore which comprises treating said ore pulps with an aqueous solution of hydroxyalkyl guar selected from the group consisting of hydroxyethyl and hydroxypropyl guar in the amount of 0.1 and 2.0 pounds of hydroxyalkyl guar per ton of uranium ore

  11. Powder Activated Carbon Pretreatment of a Microfiltration Membrane for the Treatment of Surface Water

    Yali Song

    2015-09-01

    Full Text Available This study focused on the effect of powder activated carbon (PAC adsorption on microfiltration (MF membrane performance. The results showed that PAC pretreatment offered high organic matter removal rates for both dissolved organic carbon (DOC and ultraviolet absorbance at 254 nm (UV254 during 10–200 mg/L PAC dosage. The removal efficiencies of organic matter by MF membrane filtration decreased with the increase of organic matter removal rate by PAC adsorption. PAC mainly removed organic matter of about 3 kDa molecular weight (MW. MF membrane maintained more than 5 kDa MW organic matter on the membrane after PAC adsorption. The results of membrane filtration indicated that PAC pretreatment slightly promoted membrane flux, regardless of PAC dosage. It seems that the organic matter fouling membrane was concentrated in more than 3 kDa MW. PAC removed markedly less than 3 kDa MW organic matter and had less effect on more than 3 kDa organic matter. Thus, PAC cannot reduce membrane fouling.

  12. Powder Activated Carbon Pretreatment of a Microfiltration Membrane for the Treatment of Surface Water

    Song, Yali; Dong, Bingzhi; Gao, Naiyun; Ma, Xiaoyan

    2015-01-01

    This study focused on the effect of powder activated carbon (PAC) adsorption on microfiltration (MF) membrane performance. The results showed that PAC pretreatment offered high organic matter removal rates for both dissolved organic carbon (DOC) and ultraviolet absorbance at 254 nm (UV254) during 10–200 mg/L PAC dosage. The removal efficiencies of organic matter by MF membrane filtration decreased with the increase of organic matter removal rate by PAC adsorption. PAC mainly removed organic matter of about 3 kDa molecular weight (MW). MF membrane maintained more than 5 kDa MW organic matter on the membrane after PAC adsorption. The results of membrane filtration indicated that PAC pretreatment slightly promoted membrane flux, regardless of PAC dosage. It seems that the organic matter fouling membrane was concentrated in more than 3 kDa MW. PAC removed markedly less than 3 kDa MW organic matter and had less effect on more than 3 kDa organic matter. Thus, PAC cannot reduce membrane fouling. PMID:26378552

  13. Atividade alelopática do filtrado de cultura produzido por Fusarium solani Allelopathic activity of culture filtrate produced by Fusarium solani

    A.P.S. Souza Filho

    2007-03-01

    Full Text Available As plantas daninhas se constituem no principal problema a impor limitação à exploração da agropecuária nas áreas tropicais. Entretanto, o controle químico dessas plantas tem gerado insatisfações de ordem social, quer porque contaminam as fontes de recursos naturais ou por comprometerem a qualidade dos alimentos da dieta dos animais, em geral, e dos humanos, em particular. Os objetivos deste trabalho foram identificar e caracterizar a atividade alelopática do filtrado de cultura produzido pelo fungo Fusarium solani f. sp. pipers. Foram avaliados os efeitos das toxinas, nas concentrações de 1,0 e 4,0%, sobre a germinação de sementes e o desenvolvimento da radícula e do hipocótilo das plantas daninhas malícia (Mimosa pudica e mata-pasto (Senna obtusifolia. Os resultados mostraram presença de atividade alelopática inibitória, com variações de acordo com a concentração e a planta receptora. A intensidade dos efeitos inibitórios induzidos pelo extrato esteve positivamente associada à concentração, com efeitos mais intensos verificados a 4,0%. Independentemente da concentração e do bioensaio, a espécie malícia se mostrou mais sensível aos efeitos do filtrado da cultura. O desenvolvimento da radícula foi o fator da planta mais intensamente inibido. Os resultados indicam a existência de potencial de utilização da toxina produzida pelo fungo, como fonte alternativa no controle de plantas daninhas, o que justifica estudos mais avançados.Weeds are a major problem limiting agriculture and cattle raising activities in the tropics. Current chemical control measures have raised environmental concerns due to their potential of contaminating natural resources and compromising the quality of animal feed. The objective of this paper was to identify and characterize the potential allelopathic activity of Fusarium solani f. sp. pipers culture filtrate. The effects of the toxin were analyzed at 1% and 4% concentration, on seed

  14. Drinking water biotic safety of particles and bacteria attached to fines in activated carbon process

    CHEN Wei; LIN Tao; WANG Leilei

    2007-01-01

    In this paper,the drinking water biotic safety of particles and bacteria attached to fines in activated carbon process was investigated by actual treatment process and advanced treatment pilot trial with granular activated carbon.In the experiment,the particles were detected by IBR particle calculating instrument,the activated carbon fines were counted on the basis of the most probable number (MPN) with a microscope,the total number of bacteria was analyzed between the conventional agar culture medium and the one with R2A,and the bacteria attached to activated carbon fines was resolved by the homogenization technique.The experimental results showed that the average total number of particles was 205 CNT/mL in the activated carbon effluent during a filter cycle,of which the number of particles with sizes>2μm was 77 CNT/mL more than the present particle control criterion of the American drinking water product standard (50 CNT/mL).The backwash of low density and long duration lowered particle number in the effluent.The MPN of activated carbon frees in the effluent was between 400 and 600 CNT/L,which accounted for less than 5‰ of the total particles from activated carbon filtration for a poor relative level (R2= 0.34).The microorganisms in activated carbon effluent consisted mostly of heterotrophic bacillus and the total bacteria number was five times as high as that of the inflow,i.e.the effluent from sand filter.The actual bacteria number may be truly indicated by the detection technique with R2A culture medium compared with the traditional agar cultivation.The inactivation efficiency of bacteria attached to activated carbon fines was less than 40% under 1.1 mg/L of chlorine contacting for 40 min.Results showed that the particles and bacteria attached to activated carbon fines may influence drinking water biotic safety,and that the effective control measures need to be further investigated.

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

    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.

  16. Visualization of water flow during filtration using flat filtration materials

    Hrůza Jakub

    2012-04-01

    Full Text Available Filtration materials are very important elements of some industrial appliances. Water filtration is a separation of solid materials from fluid. Solid particles are captured on the frontal area of the filtration textile and only liquid passes through it. It is important to know the filtration process in a detailed way to be able to develop filtration materials. Visualization of filtration process enables a better view of the filtration. This method also enables to determine efficiency and homogeneity of filtration using image analysis. For this purpose, a new waterfiltration measuring setup was proposed and constructed. Filtration material is mounted into the optically transparent place in the setup. Laser sheet is directed into this place as in the case of Particle Image Velocimetry measuring method. Monochrome and sensitive camera records the light scattered by seeding particles in water. The seeding particles passing through the filter serve for measuring filtration efficiency, and also for visualization of filtration process. Filtration setup enables to measure also the pressure drop and a flow. The signals are processed by National Instruments compactDAQ system and UMA software. Microfibrous and nanofibrous filtration materials are tested by this measuring method. In the case of nanofibrous filtration, appropriate size of seeding particles is needed to be used to perform a process of filtration.

  17. ACTIVATED CARBON IN WATER TREATMENT FOR DRINKS

    Олійник, С. І.; Прибильский, В. Л.; Куц, A. М.; Ковальчук, В. П.; Коваленко, O. О.

    2014-01-01

    The purpose of scientific research, the results of which are given in the article, is the improvement of the technology of water conditioning by sorption purification of water for the production of beverages, including alcoholic beverages. The subject of research was drinking water, prepared water, activated carbon such grades Silcarbon K1810, Silcarbon K835, Silcarbon K814 compared to Silcarbon K3060. During the research we are used the conventional methods of analysis in liqueur and vodka p...

  18. Production of activated carbon from microalgae

    Hernández Férez, María del Remedio; Valdés Barceló, Francisco Javier; García Cortés, Ángela Nuria; Marcilla Gomis, Antonio; Chápuli Fernández, Eloy

    2008-01-01

    Presentado como póster en el 11th Mediterranean Congress of Chemical Engineering, Barcelona 2008. Resumen publicado en el libro de actas del congreso. Activated carbon is an important filter material for the removal of different compounds such as hazardous components in exhaust gases, for purification of drinking water, waste water treatment, adsorption of pollution from liquid phases, in catalysis, electrochemistry or for gas storage and present an important demand. Theoretically, activat...

  19. Interactions of xanthines with activated carbon

    Navarrete Casas, R. [Inorganic Chemistry Department, Granada University (Ugr), E-18071 Granada (Spain)]. E-mail: rncasas@ugr.es; Garcia Rodriguez, A. [Inorganic Chemistry Department, Granada University (Ugr), E-18071 Granada (Spain); Rey Bueno, F. [Inorganic Chemistry Department, Granada University (Ugr), E-18071 Granada (Spain); Espinola Lara, A. [Inorganic Chemistry Department, Granada University (Ugr), E-18071 Granada (Spain); Valenzuela Calahorro, C. [Inorganic Chemistry Department, Granada University (Ugr), E-18071 Granada (Spain); Navarrete Guijosa, A. [Inorganic Chemistry Department, Granada University (Ugr), E-18071 Granada (Spain)

    2006-06-30

    Because of their pharmaceutical and industrial applications, we have studied the adsorption of xanthine derivates (caffeine and theophylline) by activated carbon. To this end, we examined kinetic, equilibrium and thermodynamic aspects of the process. This paper reports the kinetics results. The experimental results indicate that the process was first order in C and the overall process was assumed to involve a single, reversible adsorption-desorption process obeying a kinetic law postulated by us.

  20. Composite supercapacitor electrodes made of activated carbon/PEDOT:PSS and activated carbon/doped PEDOT

    T S Sonia; P A Mini; R Nandhini; Kalluri Sujith; Balakrishnan Avinash; S V Nair; K R V Subramanian

    2013-08-01

    In this paper, we report on the high electrical storage capacity of composite electrodes made from nanoscale activated carbon combined with either poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) or PEDOT doped with multiple dopants such as ammonium persulfate (APS) and dimethyl sulfoxide (DMSO). The composites were fabricated by electropolymerization of the conducting polymers (PEDOT:PSS, doped PEDOT) onto the nanoscale activated carbon backbone, wherein the nanoscale activated carbon was produced by ball-milling followed by chemical and thermal treatments. Activated carbon/PEDOT:PSS yielded capacitance values of 640 F g-1 and 26mF cm-2, while activated carbon/doped PEDOT yielded capacitances of 1183 F g-1 and 42 mF cm-2 at 10 mV s-1. This is more than five times the storage capacity previously reported for activated carbon–PEDOT composites. Further, use of multiple dopants in PEDOT improved the storage performance of the composite electrode well over that of PEDOT:PSS. The composite electrodes were characterized for their electrochemical behaviour, structural and morphological details and electronic conductivity and showed promise as high-performance energy storage systems.

  1. Less-costly activated carbon for sewage treatment

    Ingham, J. D.; Kalvinskas, J. J.; Mueller, W. A.

    1977-01-01

    Lignite-aided sewage treatment is based on absorption of dissolved pollutants by activated carbon. Settling sludge is removed and dried into cakes that are pyrolyzed with lignites to yield activated carbon. Lignite is less expensive than activated carbon previously used to supplement pyrolysis yield.

  2. Flexural Properties of Activated Carbon Filled Epoxy Nano composites

    Activated carbon (AC) filled epoxy nano composites obtained by mixing the desired amount of nano AC viz., bamboo stem, oil palm empty fruit bunch, and coconut shell from agricultural biomass with the epoxy resin. Flexural properties of activated carbons filled epoxy nano composites with 1 %, and 5 % filler loading were measured. In terms of flexural strength and modulus, a significant increment was observed with addition of 1 % vol and 5 % vol nano-activated carbon as compared to neat epoxy. The effect of activated carbon treated by two chemical agents (potassium hydroxide and phosphoric acid) on the flexural properties of epoxy nano composites were also investigated. Flexural strength of activated carbon-bamboo stem, activated carbon-oil palm, and activated carbon-coconut shell reinforced epoxy nano composites showed almost same value in case of 5 % potassium hydroxide activated carbon. Flexural strength of potassium hydroxide activated carbon-based epoxy nano composites was higher than phosphoric acid activated carbon. The flexural toughness of both the potassium hydroxide and phosphoric acid activated carbon reinforced composites range between 0.79 - 0.92 J. It attributed that developed activated carbon filled epoxy nano composites can be used in different applications. (author)

  3. Effects on the efficiency of activated carbon on exposure to welding fumes

    Ghosh, D. [Southern Company Services, Inc., Birmingham, AL (United States)

    1995-02-01

    It is the intention of this paper to document that certain types of welding fumes have little or no effect on the effectiveness of the carbon filter air filtration efficiency when directly exposed to a controlled amount of welding fumes for a short-term period. The welding processes studied were restricted to shielded metal arc welding (SMAW), flux cored arc welding (FCAW), gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) processes. Contrary to the SMAW and FCAW processes, the GTAW (or TIG) and the GMAW (or MIG) welding processes do not require the use of flux as part of the overall process. Credit was taken for these processes occurring in inert gas environments and producing minimal amount of smoke. It was concluded that a study involving the SMAW process would also envelop the effects of the TIG and MIG welding processes. The quantity of welding fumes generated during the arc welding process is a function of the particular process, the size and type of electrode, welding machine amperage, and operator proficiency. For this study, the amount of welding for specific testing was equated to the amount of welding normally conducted during plant unit outages. Different welding electrodes were also evaluated, and the subsequent testing was limited to an E7018 electrode which was judged to be representative of all carbon and stainless steel electrodes commonly used at the site. The effect of welding fumes on activated charcoal was tested using a filtration unit complete with prefilters, upstream and downstream high efficiency particulate air (HEPA) filters, and a carbon adsorber section. The complete system was field tested in accordance with ANSI N510 standards prior to exposing the filters and the adsorber bed to welding fumes. The carbon samples were tested at an established laboratory using ASTM D3803-1989 standards.

  4. Active carbon production from modified asphalt

    A granular activated carbons (GACs) have been prepared from some local raw materials such as Qiayarah asphalt (QA) after some modification treatments of this asphalt by various ratios of its original constituents (asphaltenes and maltens) at 180 degree C. Thermal carbonization method by sulfur and steam physical activation have been used for AC preparation. The carbons thus prepared were characterized in the term of iodine, methylene blue (MB), P-nitro phenol (PNP) and CCl4 adsorption. The BET surface area of the prepared ACs has been estimated via a calibration curve between iodine numbers and surface area determined from N2 adsorption isotherm from previous studies, also, the surface area of the prepared ACs were determined through another methods such as retention method by ethylene glycol mono ethyl ether (EGME), adsorption from vapor phase using acetone vapor and adsorption from solution method using PNP and MB as solutes. The results referred to the success of modification method for preparing ACs of good micro porosity as compared with the AC from the untreated asphalt as well as the commercial sample. (author)

  5. Microfluidic colloid filtration.

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J C; Wessling, Matthias

    2016-01-01

    Filtration of natural and colloidal matter is an essential process in today's water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a "cake layer" - often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level. PMID:26927706

  6. Microfluidic colloid filtration

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-03-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” - often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level.

  7. Magnetic-seeding filtration

    This task will investigate the capabilities of magnetic-seeding filtration for the enhanced removal of magnetic and nonmagnetic particulates from liquids. This technology appies to a wide range of liquid wastes, including groundwater, process waters, and tank supernatant. Magnetic-seeding filtration can be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal-size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes

  8. Magnetic-seeding filtration

    Depaoli, D. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    This task will investigate the capabilities of magnetic-seeding filtration for the enhanced removal of magnetic and nonmagnetic particulates from liquids. This technology appies to a wide range of liquid wastes, including groundwater, process waters, and tank supernatant. Magnetic-seeding filtration can be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal-size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes.

  9. Vibration damping with active carbon fiber structures

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

    2007-04-01

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

  10. Enlargements of filtrations and applications

    Corcuera, J M

    2012-01-01

    In this paper we review some old and new results about the enlargement of filtrations problem, as well as their applications to credit risk and insider trading problems. The enlargement of filtrations problem consists in the study of conditions under which a semimartingale remains a semimartingale when the filtration is enlarged, and, in such a case, how to find the Doob-Meyer decomposition. Filtrations may be enlarged in different ways. In this paper we consider initial and progressive filtration enlargements made by random variables and processes. Keywords: Credit Risk, Insider Trading, Enlargement of Filtrations

  11. Production of activated carbon from TCR char

    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

  12. Water Treatment Technology - Filtration.

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on filtration provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purposes of sedimentation basins and flocculation…

  13. Filtrations and Buildings

    Cornut, Christophe

    2014-01-01

    We construct and study a scheme theoretical version of the Tits vectorial building, relate it to filtrations on fiber functors, and use them to clarify various constructions pertaining to Bruhat-Tits buildings, for which we also provide a Tannakian description.

  14. Simplified greywater treatment systems: Slow filters of sand and slate waste followed by granular activated carbon.

    Zipf, Mariah Siebert; Pinheiro, Ivone Gohr; Conegero, Mariana Garcia

    2016-07-01

    One of the main actions of sustainability that is applicable to residential, commercial, and public buildings is the rational use of water that contemplates the reuse of greywater as one of the main options for reducing the consumption of drinking water. Therefore, this research aimed to study the efficiencies of simplified treatments for greywater reuse using slow sand and slow slate waste filtration, both followed by granular activated carbon filters. The system monitoring was conducted over 28 weeks, using analyses of the following parameters: pH, turbidity, apparent color, biochemical oxygen demand (BOD), chemical oxygen demand (COD), surfactants, total coliforms, and thermotolerant coliforms. The system was run at two different filtration rates: 6 and 2 m(3)/m(2)/day. Statistical analyses showed no significant differences in the majority of the results when filtration rate changed from 6 to 2 m(3)/m(2)/day. The average removal efficiencies with regard to the turbidity, apparent color, COD and BOD were 61, 54, 56, and 56%, respectively, for the sand filter, and 66, 61, 60, and 51%, respectively, for the slate waste filter. Both systems showed good efficiencies in removing surfactants, around 70%, while the pH reached values of around 7.80. The average removal efficiencies of the total and thermotolerant coliforms were of 61 and 90%, respectively, for the sand filter, and 67 and 80%, respectively, for the slate waste filter. The statistical analysis found no significant differences between the responses of the two systems, which attest to the fact that the slate waste can be a substitute for sand. The maximum levels of efficiency were high, indicating the potential of the systems, and suggesting their optimization in order to achieve much higher average efficiencies. PMID:27045540

  15. Tertiary nitrogen removal for municipal wastewater using a solid-phase denitrifying biofilter with polycaprolactone as the carbon source and filtration medium.

    Li, Peng; Zuo, Jiane; Wang, Yajiao; Zhao, Jian; Tang, Lei; Li, Zaixing

    2016-04-15

    Tertiary nitrogen removal technologies are needed to reduce the excess nitrogen that is discharged into sensitive aquatic ecosystems. An integrated solid-phase denitrification biofilter (SDNF) was developed with dual media to remove nitrate and suspended solids (SS) from the secondary effluent of municipal wastewater treatment plants. Biodegradable polymer pellets of polycaprolactone (PCL) served as the biofiltration medium and carbon source for denitrification. Long-term continuous operation of the SDNF was conducted with real secondary effluent to evaluate the denitrification performance and effects of influent nitrate loading rates (NLR) and operating temperatures. The results indicated that both nitrate and SS were effectively removed. The SDNF had a strong tolerance for fluctuations in influent NLR, and a maximum denitrification rate of 3.80 g N/(L·d) was achieved. The low temperature had a significant impact on nitrogen removal, yet the denitrification rate was still maintained at a relative high level to as much as 1.23 g N/(L·d) even at approximately 8.0 °C in winter. Nitrite accumulation and excessive organics residue in the effluent were avoided throughout the whole experiment, except on occasional days in the lag phase. The observed biomass yield was calculated to be 0.44 kgVSS/kgPCL. The microbial diversity and community structure of the biofilm in the SDNF were revealed by Illumina high-throughput sequencing. The special carbon source led to an obvious succession of microbial community from the initial inoculum (activated sludge from aerobic tanks), and included a decrease in microbial diversity and a shift in the dominant groups, which were identified to be members of the family Comamonadaceae in the SDNF. The SDNF developed in this study was verified to be an efficient technology for tertiary nitrogen removal from secondary effluent. PMID:26897042

  16. Effects of super-powdered activated carbon pretreatment on coagulation and trans-membrane pressure buildup during microfiltration

    Matsui, Yoshihiko; Hasegawa, Hiroki; Ohno, Koich; Matsushita, Taku; Mima, Satoru; Kawase, Yuji; Aizawa, Takako

    2009-01-01

    As a pretreatment for membrane microfiltration (MF), the use of powdered activated carbon (PAC) with a particle size much smaller than that of conventional PAC (super-powdered PAC, or S-PAC) has been proposed to enhance the removal of dissolved substances. In this paper, another advantage of S-PAC as a pretreatment for MF is described: the use of S-PAC attenuates transmembrane pressure increases during the filtration operation. The floc particles that formed during coagulation preceded by S-P...

  17. ACTIVITY OF FUNGAL CULTURE FILTRATES AGAINST SOYBEAN CYST NEMATODE AND ROOT-KNOT NEMATODE EGG HATCH AND JUVENILE MOTILITY

    Fungi were isolated from soybean cyst nematode (Heterodera glycines) eggs collected in China, and 253 isolates were assayed for production of compounds active against H. glycines and root-knot nematode (Meloidogyne incognita). Fungal isolates were grown for 3 and 7 days in potato dextrose broth (PD...

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

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

    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....

  19. Physicochemical and sensory changes in aged sugarcane spirit submitted to filtering with activated carbon filter

    Felipe Cimino Duarte

    2012-09-01

    Full Text Available Sugarcane spirit is a drink considered as a national symbol of Brazil. It is produced by large producers and by about 30 thousand small and medium home-distilling producers dispersed throughout the country. The copper originating from the home-distillers can become a serious problem since at high concentrations in beverages it may cause serious human health problems. Therefore, the objective of this study was to investigate the influence of the activated carbon used in commercial filters on the physicochemical and sensory characteristics of aged sugarcane spirit. Analyses of copper, dry extract, alcoholic degree, higher alcohols, volatile acids, aldehydes, esters, furfural, and methanol were performed. The sensory evaluation was performed by seven selected trained judges, who analyzed the yellow color, woody aroma and flavor, and intensity of alcoholic aroma and flavor of the cane spirit before and after the filtration process. The sensory tests were carried out using a 9 cm non-structured intensity scale. A reduction was observed in all compounds analyzed physicochemically, except for the esters, which increased after filtration. This increase is probably due to the esterification of the alcohols and acids present. According to the sensory results obtained, a reduction was observed in the intensity of the yellow color, aroma, and wood flavor characteristics, the major characteristics of the aging process.

  20. Integrating powdered activated carbon into wastewater tertiary filter for micro-pollutant removal.

    Hu, Jingyi; Aarts, Annelies; Shang, Ran; Heijman, Bas; Rietveld, Luuk

    2016-07-15

    Integrating powdered activated carbon (PAC) into wastewater tertiary treatment is a promising technology to reduce organic micro-pollutant (OMP) discharge into the receiving waters. To take advantage of the existing tertiary filter, PAC was pre-embedded inside the filter bed acting as a fixed-bed adsorber. The pre-embedding (i.e. immobilization) of PAC was realized by direct dosing a PAC solution on the filter top, which was then promoted to penetrate into the filter media by a down-flow of tap water. In order to examine the effectiveness of this PAC pre-embedded filter towards OMP removal, batch adsorption tests, representing PAC contact reactor (with the same PAC mass-to-treated water volume ratio as in the PAC pre-embedded filter) were performed as references. Moreover, as a conventional dosing option, PAC was dosed continuously with the filter influent (i.e. the wastewater secondary effluent with the investigated OMPs). Comparative results confirmed a higher OMP removal efficiency associated with the PAC pre-embedded filter, as compared to the batch system with a practical PAC residence time. Furthermore, over a filtration period of 10 h (approximating a realistic filtration cycle for tertiary filters), the continuous dosing approach resulted in less OMP removal. Therefore, it was concluded that the pre-embedding approach can be preferentially considered when integrating PAC into the wastewater tertiary treatment for OMP elimination. PMID:27082256

  1. Evaluation of chromate reductase activity in the cell-free culture filtrate of Arthrobacter sp. SUK 1201 isolated from chromite mine overburden.

    Dey, Satarupa; Paul, A K

    2016-08-01

    Arthrobacter sp. SUK 1201, a chromate resistant and reducing bacterium isolated from chromite mine overburden of Sukinda valley, Odisha, India has been evaluated for its hexavalent chromium [Cr(VI)] reduction potential using cell-free culture filtrate as extracellular chromate reductase enzyme. Production of the enzyme was enhanced in presence of Cr(VI) and its reducing efficiency was increased with increasing concentration of Cr(VI). The Michaelis-Menten constant (Km) and the maximum specific velocity (Vmax) of the extracellular Cr(VI) reductase were calculated to be 54.03 μM Cr(VI) and 5.803 U mg(-1) of protein respectively showing high affinity towards Cr(VI). The reducing activity of the enzyme was maximum at pH 6.5-7.5 and at a temperature of 35 °C and was dependent on NADH. The enzyme was tolerant to different metals such as Mn(II), Mg(II) and Fe(III) and was able to reduce Cr(VI) present in chromite mine seepage. These findings suggest that the extracellular chromate reductase of Arthrobacter sp. SUK 1201 has a great promise for use in Cr(VI) detoxification under different environmental conditions, particularly in the mining waste water treatment systems. PMID:27176938

  2. Clinical and radiographic study of activated carbon workers.

    Uragoda, C. G.

    1989-01-01

    Activated carbon is made in Sri Lanka by passing steam through charcoal made from coconut shells. The carbon does not contain free silica. Sixty six men who had worked in a factory making activated carbon for an average of 7.2 years had no more respiratory symptoms than a control group, and none showed radiological evidence of pneumoconiosis. There was no evidence that people exposed to charcoal and pure carbon for up to 11 years are at risk of developing pneumoconiosis.

  3. Functoriality of the coniveau filtration

    Arapura, Donu; Kang, Su-Jeong

    2005-01-01

    There is a natural descending filtration on the singular cohomology of a complex smooth projective variety called the coniveau filtration. The generalized Hodge conjecture would imply, rather trivially, that the coniveau filtration is compatible with pushforwards, pullbacks and products. The purpose of this paper is to prove this statement unconditionally. This completes the argument in math.AG/0102070.

  4. Volumetric and superficial characterization of carbon activated; Caracterizacion volumetrica y superficial de carbon activado

    Carrera G, L.M.; Garcia S, I.; Jimenez B, J.; Solache R, M.; Lopez M, B.; Bulbulian G, S.; Olguin G, M.T. [Departamento de Quimica, Gerencia de Ciencias Basicas, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    The activated carbon is the resultant material of the calcination process of natural carbonated materials as coconut shells or olive little bones. It is an excellent adsorbent of diluted substances, so much in colloidal form, as in particles form. Those substances are attracted and retained by the carbon surface. In this work is make the volumetric and superficial characterization of activated carbon treated thermically (300 Centigrade) in function of the grain size average. (Author)

  5. Activated Carbon Composites for Air Separation

    Baker, Frederick S [ORNL; Contescu, Cristian I [ORNL; Tsouris, Costas [ORNL; Burchell, Timothy D [ORNL

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

    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.

  7. Facility of aerosol filtration

    Said invention relates to a facility of aerosol filtration, particularly of sodium aerosols. Said facility is of special interest for fast reactors where sodium fires involve the possibility of high concentrations of sodium aerosols which soon clog up conventional filters. The facility intended for continuous operation, includes at the pre-filtering stage, means for increasing the size of the aerosol particles and separating clustered particles (cyclone separator)

  8. Detergent zeolite filtration plant

    Stanković Mirjana S.

    2003-01-01

    Full Text Available The IGPC Engineering Department designed basic projects for detergent zeolite filtration plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE, Italy, in 1997, for increasing detergent zeolite production, from 50,000 to 100,000 t/y. The main goal was to increase the detergent zeolite production capacity. The technological cycle of the filtrate was closed, and no effluents emitted, and there is no pollution. The detergent zeolite filtration process is fully continuous, by which a significant improvement in zeolite production was achieved, both in unification of quality of the product and in simplifying production. This process is fully automatized, and the product has uniform quality. The production process can be controlled manually, which is necessary during start-up, and repairs. By installing additional process equipment (centrifugal pumps, a vacuum system and belt filter technological bottlenecks were overcome by adjusting the work of centrifugal pumps and belt filter, and also by optimizing the capacities of process equipment.

  9. Measurement of carbon activity of sodium using nickel tabs and the Harwell Carbon Meter - Preliminary experience

    Carbon can have an important effect on the mechanical properties of certain constructional materials likely to be used in the LMFBRs. Transfer of carbon will occur between the metal and the sodium at any particular location to bring the chemical potential of carbon in both components to the sam: value. Thus, in a mixed system containing austenitic stainless steel and unstabilized ferritic steel, carbon could be transferred by the sodium from the high carbon activity ferritic to the lower activity austenitic steel. Loss of carbon from the unstabilized ferritic steel leads to a weaker, more ductile material, while carburization of the stainless steel could lead to its embrittlement. Similarly carbon entering the coolant in the form of oil from leaking mechanical pumps could have similar effects on the mechanical property of stainless steels. In the light of these possibilities it is essential to measure the carbon activity of the sodium so that its effect on materials properties can be predicted

  10. Grey water treatment in urban slums by a filtration system: optimisation of the filtration medium.

    Katukiza, A Y; Ronteltap, M; Niwagaba, C B; Kansiime, F; Lens, P N L

    2014-12-15

    Two uPVC columns (outer diameter 160 cm, internal diameter 14.6 cm and length 100 cm) were operated in parallel and in series to simulate grey water treatment by media based filtration at unsaturated conditions and constant hydraulic loading rates (HLR). Grey water from bathroom, laundry and kitchen activities was collected from 10 households in the Bwaise III slum in Kampala (Uganda) in separate containers, mixed in equal proportions followed by settling, prior to transferring the influent to the tanks. Column 1 was packed with lava rock to a depth of 60 cm, while column 2 was packed with lava rock (bottom 30 cm) and silica sand, which was later replaced by granular activated carbon (top 30 cm) to further investigate nutrient removal from grey water. Operating the two filter columns in series at a HLR of 20 cm/day resulted in a better effluent quality than at a higher (40 cm/day) HLR. The COD removal efficiencies by filter columns 1 and 2 in series amounted to 90% and 84% at HLR of 20 cm/day and 40 cm/day, respectively. TOC and DOC removal efficiency amounted to 77% and 71% at a HLR of 20 cm/day, but decreased to 72% and 67% at a HLR of 40 cm/day, respectively. The highest log removal of Escherichia coli, Salmonella sp. and total coliforms amounted to 3.68, 3.50 and 3.95 at a HLR of 20 cm/day respectively. The overall removal of pollutants increased with infiltration depth, with the highest pollutant removal efficiency occurring in the top 15 cm layer. Grey water pre-treatment followed by double filtration using coarse and fine media has the potential to reduce the grey water pollution load in slum areas by more than 60%. PMID:25169645

  11. THE ROLE OF ACTIVATED CARBON IN SOLVING ECOLOGICAL PROBLEMS

    V. M. Mukhin

    2008-06-01

    Full Text Available The authors present a brief analysis of the current global situation concerning the utilization of activated carbon in various fields. The article presents data concerning the synthesis and adsorption and structure properties of new activated carbons, used for solving ecological problems. The authors investigated the newly obtained activated carbons in comparison with several AC marks known in the world. It has been shown that currently synthesized AC are competitive with foreign marks.

  12. HYDROGEN SULFIDE ADSORPTION BY ALKALINE IMPREGNATED COCONUT SHELL ACTIVATED CARBON

    HUI SUN CHOO

    2013-12-01

    Full Text Available Biogas is one type of renewable energy which can be burnt to produce heat and electricity. However, it cannot be burnt directly due to the presence of hydrogen sulfide (H2S which is highly corrosive to gas engine. In this study, coconut shell activated carbon (CSAC was applied as a porous adsorbent for H2S removal. The effect of amount of activated carbon and flow rate of gas stream toward adsorption capacity were investigated. Then, the activated carbons were impregnated by three types of alkaline (NaOH, KOH and K2CO3 with various ratios. The effects of various types of alkaline and their impregnation ratio towards adsorption capacity were analysed. In addition, H2S influent concentration and the reaction temperature on H2S adsorption were also investigated. The result indicated that adsorption capacity increases with the amount of activated carbon and decreases with flow rate of gas stream. Alkaline impregnated activated carbons had better performance than unimpregnated activated carbon. Among all impregnated activated carbons, activated carbon impregnated by K2CO3 with ratio 2.0 gave the highest adsorption capacity. Its adsorption capacity was 25 times higher than unimpregnated activated carbon. The result also indicated that the adsorption capacity of impregnated activated carbon decreased with the increment of H2S influent concentration. Optimum temperature for H2S adsorption was found to be 50˚C. In this study, the adsorption of H2S on K2CO3 impregnated activated carbon was fitted to the Langmuir isotherm. The fresh and spent K2CO3 impregnated activated carbon were characterized to study the adsorption process.

  13. Intravascular Neutrophil Activation Due to Carbon Monoxide Poisoning

    Thom, Stephen R.; Bhopale, Veena M.; Han, Shih-Tsung; Clark, James M.; HARDY, KEVIN R.

    2006-01-01

    Rationale: We hypothesized that platelet–neutrophil interactions occur as a result of acute carbon monoxide (CO) poisoning, and subsequent neutrophil activation triggers events that cause neurologic sequelae.

  14. Quantitative detection of powdered activated carbon in wastewater treatment plant effluent by thermogravimetric analysis (TGA).

    Krahnstöver, Therese; Plattner, Julia; Wintgens, Thomas

    2016-09-15

    For the elimination of potentially harmful micropollutants, powdered activated carbon (PAC) adsorption is applied in many wastewater treatment plants (WWTP). This holds the risk of PAC leakage into the WWTP effluent and desorption of contaminants into natural water bodies. In order to assess a potential PAC leakage, PAC concentrations below several mg/L have to be detected in the WWTP effluent. None of the methods that are used for water analysis today are able to differentiate between activated carbon and solid background matrix. Thus, a selective, quantitative and easily applicable method is still needed for the detection of PAC residues in wastewater. In the present study, a method was developed to quantitatively measure the PAC content in wastewater by using filtration and thermogravimetric analysis (TGA), which is a well-established technique for the distinction between different solid materials. For the sample filtration, quartz filters with a temperature stability up to 950 °C were used. This allowed for sensitive and well reproducible measurements, as the TGA was not affected by the presence of the filter. The sample's mass fractions were calculated by integrating the mass decrease rate obtained by TGA in specific, clearly identifiable peak areas. A two-step TGA heating method consisting of N2 and O2 atmospheres led to a good differentiation between PAC and biological background matrix, thanks to the reduction of peak overlapping. A linear correlation was found between a sample's PAC content and the corresponding peak areas under N2 and O2, the sample volume and the solid mass separated by filtration. Based on these findings, various wastewater samples from different WWTPs were then analyzed by TGA with regard to their PAC content. It was found that, compared to alternative techniques such as measurement of turbidity or total suspended solids, the newly developed TGA method allows for a quantitative and selective detection of PAC concentrations down to 0

  15. Filtration d’une huile dopée avec quatre hydrocarbures aromatiques polycycliques (HAP) sur des plaques garnies en charbon actif

    Sidani Marion; Gaud Marie; Pagès Xavier; Morin Odile; Gouband Morgan; Buchoux Jérôme; Goulet Jérémy; Birot Céline; Galan Virginie

    2012-01-01

    Powdered activated carbon is used in oils and fats refining to bleach and purify vegetable oils and fish oils. Actually, this powder makes it possible to detoxify crude fish oils and to eliminate contaminants like PAH, dioxin and PCB. Nevertheless, the powdered activated carbon used is painful because it is pulverulent. Nowadays, producers advise filtration plates filled with this powder. The aim of this study is to check the efficiency of such plates in the PAH elimination and verify the res...

  16. The Adsorption Mechanism of Modified Activated Carbon on Phenol

    Lin J. Q.

    2016-01-01

    Full Text Available Modified activated carbon was prepared by thermal treatment at high temperature under nitrogen flow. The surface properties of the activated carbon were characterized by Boehm titration, BET and point of zero charge determination. The adsorption mechanism of phenol on modified activated carbon was explained and the adsorption capacity of modified activated carbon for phenol when compared to plain activated carbon was evaluated through the analysis of adsorption isotherms, thermodynamic and kinetic properties. Results shows that after modification the surface alkaline property and pHpzc value of the activated carbon increase and the surface oxygen-containing functional groups decrease. The adsorption processes of the plain and modified carbon fit with Langmuir isotherm equation well, and the maximum adsorption capacity increase from 123.46, 111.11, 103.09mg/g to 192.31, 178.57, 163,93mg/g under 15, 25 and 35°C after modification, respectively. Thermodynamic parameters show that the adsorption of phenol on activated carbon is a spontaneously exothermic process of entropy reduction, implying that the adsorption is a physical adsorption. The adsorption of phenol on activated carbon follows the pseudo-second-order kinetics (R2>0.99. The optimum pH of adsorption is 6~8.

  17. Efficient L-lactic acid fermentation by the mold Rhizopus oryzae using activated carbon

    Koide, M.; Hirata, M.; Gaw, M.; Takanashi, H.; Hano, T. [Oita Univ, Oita (Japan). Dept. of Applied Chemistry

    2004-11-01

    Batch fermentations of Rhizopus oryzae AHU 6537 in medium containing granular activated carbon from coal, powder activated carbon from coal or granular activated carbon from coconut were carried out in an airlift bioreactor. As a result, fermentation broths were decolorized by activated carbon, and clearer fermentation broths were obtained than in fermentation without activated carbon. With activated carbon from coal, the cells formed smaller pellets than in fermentation without activated carbon, and fermentation performance was improved. Productivity was further improved by increasing the amount of activated carbon from coal. Therefore, the productivity of lactic acid fermentation could be improved by selecting a suitable activated carbon and by controlling the amount of activated carbon.

  18. Interaction forces between waterborne bacteria and activated carbon particles.

    Busscher, Henk J; Dijkstra, Rene J B; Langworthy, Don E; Collias, Dimitris I; Bjorkquist, David W; Mitchell, Michael D; Van der Mei, Henny C

    2008-06-01

    Activated carbons remove waterborne bacteria from potable water systems through attractive Lifshitz-van der Waals forces despite electrostatic repulsion between negatively charged cells and carbon surfaces. In this paper we quantify the interaction forces between bacteria with negatively and positively charged, mesoporous wood-based carbons, as well as with a microporous coconut carbon. To this end, we glued carbon particles to the cantilever of an atomic force microscope and measured the interaction forces upon approach and retraction of thus made tips. Waterborne Raoultella terrigena and Escherichia coli adhered weakly (1-2 nN) to different activated carbon particles, and the main difference between the activated carbons was the percentage of curves with attractive sites revealed upon traversing of a carbon particle through the bacterial EPS layer. The percentage of curves showing adhesion forces upon retraction varied between 21% and 69%, and was highest for R. terrigena with positively charged carbon (66%) and a coconut carbon (69%). Macroscopic bacterial removal by the mesoporous carbon particles increased with increasing percentages of attractive sites revealed upon traversing a carbon particle through the outer bacterial surface layer. PMID:18405910

  19. 75 FR 981 - Certain Activated Carbon From the People's Republic of China: Notice of Rescission of Changed...

    2010-01-07

    ... powdered activated carbon (``PAC''), granular activated carbon (``GAC''), and pelletized activated carbon... International Trade Administration Certain Activated Carbon From the People's Republic of China: Notice of... circumstance review (``CCR'') of the antidumping duty order on certain activated carbon from the......

  20. Magnetic flocculation and filtration

    Yiacoumi, Sotira; Chin, Ching-Ju; Yin, Tung-Yu [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering; Tsouris, C., DePaoli, D.W.; Chattin, M.R.; Spurrier, M. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    A model is available in predicting flocculation frequencies between particles of various properties under the influence of a magnetic field. This model provides a basic understanding of fundamental phenomena, such as particle-particle and particle-collector interactions, occurring in HGMF (high gradient magnetic field), and will be extended to describe experimental data of particle flocculation and filtration and predict the performance of high- gradient magnetic filters. It is also expected that this model will eventually lead to a tool for design and optimization of magnetic filters for environmental, metallurgical, biochemical, and other applications.

  1. Some aspects of activated carbon selection for radioactive iodine adsorption

    A method is suggested and technology developed for testing the activated carbon applicability for iodine filters. Testing results are presented for the air clean-up both under NPP normal operation conditions and during accidents. The activated carbon produced in Poland is compared with the imported one with respect to its integral and differential efficiency of CH3131I adsorption

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

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

    2013-04-01

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

  3. Studies on adsorptive desulfurization by activated carbon

    Rakesh Kumar, D.; Srivastava, Vimal Chandra [Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand (India)

    2012-05-15

    Sulfur removal using adsorption requires a proper process parametric study to determine its optimal performance characteristics. In this study, response surface methodology was employed for sulfur removal from model oil (dibenzothiophene; DBT dissolved in iso-octane) using commercial activated carbon (CAC) as an adsorbent. Experiments were carried out as per central composite design with four input parameters such as initial concentration (C{sub 0}: 100-900 mg/L), adsorbent dosage (m: 2-22 g/L), time of adsorption (t: 15-735 min), and temperature (T: 10-50 C). Regression analysis showed good fit of the experimental data to the second-order polynomial model with coefficient of determination R{sup 2}-value of 0.9390 and Fisher F-value of 16.5. The highest removal of sulfur by CAC was obtained with m = 20 g/L, t = 6 h, and T = 30 C. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Enhanced Capacitive Characteristics of Activated Carbon by Secondary Activation

    YANG Hui; LU Tian-hong; Yoshio Masaki

    2004-01-01

    The effect of the improvement of commercial activated carbon(AC) on its specific capacitance and high rate capability of double layer(dl) charging/discharging process has been studied. The improvement of AC was carried out via a secondary activation under steam in the presence of catalyst NiCl2, and the suitable condition was found to be a heat treatment at about 875 ℃ for 1 h. Under those conditions, the discharge specific capacitance of the improved AC increases up to 53.67 F/g, showing an increase of about 25% as compared with that of as-received AC. The good rectangular-shaped voltammograms and A.C. impedance spectra prove that the high rate capability of the capacitor made of the improved AC is enhanced significantly. The capacitance resistance(RC) time constant of the capacitor containing the improved AC is 1.74 s, which is much lower than that of the one containing as-received AC(an RC value of 4. 73 s). It is noted that both kinds of AC samples show a similar specific surface area and pore size distribution, but some changes have taken place in the carbon surface groups, especially a decrease in the concentration of surface carbonyl groups after the improvement, which have been verified by means of X-photoelectron spectroscopy. Accordingly, it is suggested that the decrease in the concentration of surface carbonyl groups for the improved AC is beneficial to the organic electrolyte ion penetrating into the pores, thus leading to the increase in both the specific capacitance and high rate capability of the supercapacitor.

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

    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.

  6. Adsorption of EDTA on activated carbon from aqueous solutions

    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 R2 = 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 (Ea, ΔG0, ΔH0, ΔS0) obtained indicate the endothermic nature of EDTA adsorption on activated carbon.

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

    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.

  8. Magnetic-seeding filtration

    DePaoli, D.W.; Tsouris, C. [Oak Ridge National Lab., TN (United States); Yiacoumi, Sotira

    1997-10-01

    Magnetic-seeding filtration is a technology under development for the enhanced removal of magnetic and non-magnetic particulates from liquids. This process involves the addition of a small amount of magnetic seed particles (such as naturally occurring iron oxide) to a waste suspension, followed by treatment with a magnetic filter. Non-magnetic and weakly magnetic particles are made to undergo nonhomogeneous flocculation with the seed particles, forming flocs of high magnetic susceptibility that are readily removed by a conventional high-gradient magnetic filter. This technology is applicable to a wide range of liquid wastes, including groundwater, process waters, and tank supernatants. Magnetic-seeding filtration may be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes. Waste stream characteristics for which the technology may be applicable include (1) particle sizes ranging from relatively coarse (several microns) to colloidal particles, (2) high or low radiation levels, (3) broad-ranging flow rates, (4) low to moderate solids concentration, (5) cases requiring high decontamination factors, and (6) aqueous or non-aqueous liquids. At this point, the technology is at the bench-scale stage of development; laboratory studies and fundamental modeling are currently being employed to determine the capabilities of the process.

  9. Science Letters: Nitrogen doping of activated carbon loading Fe2O3 and activity in carbon-nitric oxide reaction

    WAN Xian-kai; ZOU Xue-quan; SHI Hui-xiang; WANG Da-hui

    2007-01-01

    Nitrogen doping of activated carbon loading Fe2O3 was performed by annealing in ammonia, and the activity of the modified carbon for NO reduction was studied in the presence of oxygen. Results show that Fe2O3 enhances the amount of surface oxygen complexes and facilitates nitrogen incorporation in the carbon, especially in the form of pyridinic nitrogen. The modified carbon shows excellent activity for NO reduction in the low temperature regime (<500 ℃) because of the cooperative effect of Fe2O3 and the surface nitrogen species.

  10. Adsorption of radon from a humid atmosphere on activated carbon

    Temperature and relative humidity can influence the adsorption capacity of radon on activated carbon to a great extent, depending on the physical properties of the carbon. Experiments were carried out to measure the radon uptake by an activated carbon in the presence of water vapor in a specially designed adsorption apparatus. The radon concentrations in the gas and solid phases were measured simultaneously once the adsorption equilibrium and the radioactive equilibrium between the radon daughter products were reached. The experiments in the presence of water vapor were carried out using two approaches. In one case the activated carbon was preequilibrated with water vapor prior to exposing it to radon. In the other case the carbon was exposed to a mixture of water vapor and radon. The uptake capacity for radon decreased substantially when both components were introduced together compared to when carbon was preequilibrated with water

  11. Production of activated carbon from Atili seed shells

    Nehemiah Samuel MAINA

    2014-11-01

    Full Text Available Activated carbon was produced from atili (black date seed shells by chemical activation with phosphoric acid as an activating agent. Carbonization was done at temperatures of 350°C, 450°C, 550°C, 650°C and at corresponding resident times of 20, 30, 40, 50 and 60 minutes respectively in a muffle furnace. The study involved the determination of yield, carbon content, burn-off, moisture content, and ash content as well as the temperature and suitable resident time for carbonization. The result showed that, increasing the carbonization temperature from 350°C to 650°C as well as increasing the corresponding resident time from 20 to 60 minutes led to a decrease in carbonization yield as well as an increase in burn off. An increase in carbonization time led to a decrease in ash content while an increase in carbonization temperature led to a decrease in the moisture content. The yield, burn-off and ash content obtained at a carbonization temperature of 650°C and at a corresponding time of 60 minutes were found to be 68.29%, 31.71% and 0.75% respectively while the highest carbon content (99.16 and lowest moisture content (0.09 was obtained at this same temperature and corresponding time. The activated carbon produced gave a yield of 99.37%, ash content (2.01%, moisture content (4.20%, carbon content (93.79%, burn off (0.63% and pH of 6.752. These properties therefore indicate the suitability of the activated carbon produced.

  12. EM Task 9 - Centrifugal membrane filtration

    The overall project consists of several integrated research phases related to the applicability, continued development, demonstration, and commercialization of the SpinTek centrifugal membrane filtration process. Work performed during this reporting period consisted of Phase 2 evaluation of the SpinTek centrifugal membrane filtration technology and Phase 3, Technology Partnering. During Phase 1 testing conducted at the EERC using the SpinTek ST-IIL unit operating on a surrogate tank waste, a solids cake developed on the membrane surface. The solids cake was observed where linear membrane velocities were less than 17.5 ft/s and reduced the unobstructed membrane surface area up to 25%, reducing overall filtration performance. The primary goal of the Phase 2 research effort was to enhance filtration performance through the development and testing of alternative turbulence promoter designs. The turbulence promoters were designed to generate a shear force across the entire membrane surface sufficient to maintain a self-cleaning membrane capability and improve filtration efficiency and long-term performance. Specific Phase 2 research activities included the following: System modifications to accommodate an 11-in.-diameter, two-disk rotating membrane assembly; Development and fabrication of alternative turbulence promoter designs; Testing and evaluation of the existing and alternative turbulence promoters under selected operating conditions using a statistically designed test matrix; and Data reduction and analysis; The objective of Phase 3 research was to demonstrate the effectiveness of SpinTek's centrifugal membrane filtration as a pretreatment to remove suspended solids from a liquid waste upstream of 3M's WWL cartridge technology for the selective removal of technetium (Tc)

  13. Treatment of micropollutants in municipal wastewater: Ozone or powdered activated carbon?

    Margot, Jonas, E-mail: jonas.margot@epfl.ch [School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 2, 1015 Lausanne (Switzerland); Kienle, Cornelia, E-mail: cornelia.kienle@oekotoxzentrum.ch [Swiss Centre for Applied Ecotoxicology, Eawag/EPFL, Überlandstrasse 133, 8600 Dübendorf (Switzerland); Magnet, Anoÿs, E-mail: anoys.magnet@lausanne.ch [Sanitation Service, City of Lausanne, Rue des terreaux 33, 1002 Lausanne (Switzerland); Weil, Mirco, E-mail: m.weil@ect.de [ECT Oekotoxikologie GmbH, Boettgerstrasse 2-14, 65439 Floersheim/Main (Germany); Rossi, Luca, E-mail: luca.rossi@epfl.ch [School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 2, 1015 Lausanne (Switzerland); Alencastro, Luiz Felippe de, E-mail: felippe.dealencastro@epfl.ch [School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 2, 1015 Lausanne (Switzerland); Abegglen, Christian, E-mail: christian.abegglen@vsa.ch [Swiss Federal Institute of Aquatic Science and Technology (Eawag), Überlandstrasse 133, 8600 Dübendorf (Switzerland); Thonney, Denis, E-mail: denis.thonney@sige.ch [Sanitation Service, City of Lausanne, Rue des terreaux 33, 1002 Lausanne (Switzerland); Chèvre, Nathalie, E-mail: nathalie.chevre@unil.ch [Faculty of Geosciences and the Environment, University of Lausanne, 1015 Lausanne (Switzerland); Schärer, Michael, E-mail: michael.schaerer@bafu.admin.ch [Federal Office for the Environment (FOEN), Water Division, 3003 Bern (Switzerland); and others

    2013-09-01

    Many organic micropollutants present in wastewater, such as pharmaceuticals and pesticides, are poorly removed in conventional wastewater treatment plants (WWTPs). To reduce the release of these substances into the aquatic environment, advanced wastewater treatments are necessary. In this context, two large-scale pilot advanced treatments were tested in parallel over more than one year at the municipal WWTP of Lausanne, Switzerland. The treatments were: i) oxidation by ozone followed by sand filtration (SF) and ii) powdered activated carbon (PAC) adsorption followed by either ultrafiltration (UF) or sand filtration. More than 70 potentially problematic substances (pharmaceuticals, pesticides, endocrine disruptors, drug metabolites and other common chemicals) were regularly measured at different stages of treatment. Additionally, several ecotoxicological tests such as the Yeast Estrogen Screen, a combined algae bioassay and a fish early life stage test were performed to evaluate effluent toxicity. Both treatments significantly improved the effluent quality. Micropollutants were removed on average over 80% compared with raw wastewater, with an average ozone dose of 5.7 mg O{sub 3} l{sup −1} or a PAC dose between 10 and 20 mg l{sup −1}. Depending on the chemical properties of the substances (presence of electron-rich moieties, charge and hydrophobicity), either ozone or PAC performed better. Both advanced treatments led to a clear reduction in toxicity of the effluents, with PAC-UF performing slightly better overall. As both treatments had, on average, relatively similar efficiency, further criteria relevant to their implementation were considered, including local constraints (e.g., safety, sludge disposal, disinfection), operational feasibility and cost. For sensitive receiving waters (drinking water resources or recreational waters), the PAC-UF treatment, despite its current higher cost, was considered to be the most suitable option, enabling good removal of

  14. Treatment of micropollutants in municipal wastewater: Ozone or powdered activated carbon?

    Many organic micropollutants present in wastewater, such as pharmaceuticals and pesticides, are poorly removed in conventional wastewater treatment plants (WWTPs). To reduce the release of these substances into the aquatic environment, advanced wastewater treatments are necessary. In this context, two large-scale pilot advanced treatments were tested in parallel over more than one year at the municipal WWTP of Lausanne, Switzerland. The treatments were: i) oxidation by ozone followed by sand filtration (SF) and ii) powdered activated carbon (PAC) adsorption followed by either ultrafiltration (UF) or sand filtration. More than 70 potentially problematic substances (pharmaceuticals, pesticides, endocrine disruptors, drug metabolites and other common chemicals) were regularly measured at different stages of treatment. Additionally, several ecotoxicological tests such as the Yeast Estrogen Screen, a combined algae bioassay and a fish early life stage test were performed to evaluate effluent toxicity. Both treatments significantly improved the effluent quality. Micropollutants were removed on average over 80% compared with raw wastewater, with an average ozone dose of 5.7 mg O3 l−1 or a PAC dose between 10 and 20 mg l−1. Depending on the chemical properties of the substances (presence of electron-rich moieties, charge and hydrophobicity), either ozone or PAC performed better. Both advanced treatments led to a clear reduction in toxicity of the effluents, with PAC-UF performing slightly better overall. As both treatments had, on average, relatively similar efficiency, further criteria relevant to their implementation were considered, including local constraints (e.g., safety, sludge disposal, disinfection), operational feasibility and cost. For sensitive receiving waters (drinking water resources or recreational waters), the PAC-UF treatment, despite its current higher cost, was considered to be the most suitable option, enabling good removal of most micropollutants

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

    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.

  16. Studies relevant to the catalytic activation of carbon monoxide

    Ford, P.C.

    1992-06-04

    Research activity during the 1991--1992 funding period has been concerned with the following topics relevant to carbon monoxide activation. (1) Exploratory studies of water gas shift catalysts heterogenized on polystyrene based polymers. (2) Mechanistic investigation of the nucleophilic activation of CO in metal carbonyl clusters. (3) Application of fast reaction techniques to prepare and to investigate reactive organometallic intermediates relevant to the activation of hydrocarbons toward carbonylation and to the formation of carbon-carbon bonds via the migratory insertion of CO into metal alkyl bonds.

  17. Integrative filtration research and sustainable nanotechnology

    Jing Wang; Drew Thompson; David Y.H.Pui

    2013-01-01

    With the wide applications of nanomaterials in an array of industries,more concerns are being raised about the occupational health and safety of nanoparticles in the workplace,and implications of nanotechnology on the environment and living systems.Studies on environmental,health and safety (EHS) issues of nanomaterials play a significant role in public acceptance,and eventual sustainability,of nanotechnology.We present research results on three aspects of the EHS studies:characterization and measurement of nanoparticles,nanoparticle emission and exposure at workplaces,and control and abatement of nanoparticle release using filtration technology.Measurement of nanoparticle agglomerates using a newly developed instrument,the Universal Nanoparticle Analyzer,is discussed.Nanoparticle emission and exposure measurement results for carbon nanotubes in the manufacture of nanocomposites and for silicon nanoparticles in their production at a pilot scale facility are presented.Filtration of nanoparticles and nanoparticle agglomerates are also studied.

  18. Urea elimination using a cold activated-carbon artificial tubulus for hemofiltration.

    Lehmann, H D; Marten, R; Fahrner, I; Gullberg, C A

    1981-11-01

    Urea adsorption on active carbon is reversible and temperature-dependent. Urea adsorption isotherms of different carbons were determined at 0 degrees C and 65 degrees C within the equilibrium concentration range of 1.0-3.4 gm/L. At low urea concentrations considerable differences (3.4-13.0 gm/kg carbon at concentrations of 1.0 gm/L) were found between different types of activated carbon. The overall internal surface area was of minor importance compared to the pore size distribution. Adsorbing at low temperature, desorbing at high temperature, and flushing the carbon adsorber with a limited volume of the liquid to be purified yielded an "artificial urine." Compared to the original urea concentration of the filtrate, this "artificial urine" had an increased urea concentration. From a 36-liter volume containing 90 grams urea dissolved in saline, 18 liters were recirculated at a flow rate of 100 ml/min. The influence of adsorption and desorption time intervals was evaluated. After one to one and a half hours the carbon was saturated with urea. After saturation, about 1.4 grams urea were eliminated per cycle. In the "artificial urine" urea concentrations of up to 4.5 gm/L were found when the original solution contained only 2.5 gm/L. In the "patient" volume the urea concentration decreased from 2.5 gm/L to 1.9-2.1 gm/L. Within three hours a total of 22 grams of urea was removed by 3 x 120 grams activated carbon corresponding to removal of 50% of the urea passing the "artificial tubulus." The advantage of this system is that after priming, no additional physiological solution would be necessary. The necessity of excessive safety controls, additional electrolyte adjustment, energy demand in the form of direct current, and great amounts of waste in solid form lead to the conclusion that for intermittent hemofiltration treatment, commercially produced and controlled infusion solution is preferable. PMID:7325876

  19. Superior capacitive performance of active carbons derived from Enteromorpha prolifera

    Highlights: • An ocean biomass, Entromorphra prolifera, has been processed into supercapacitor electrodes. • KOH activation can prepare hierarchical porous carbon. • The as-prepared carbons have high capacitance with good rate capability. • This work provided an approach to value-added products from an ocean biomass. - Abstract: Enteromorpha prolifera (E.prolifera), an ocean biomass, was used as raw materials to prepare active carbons by a two-step strategy (pre-carbonization followed by chemical activation). The as-prepared active carbons have been characterized by a variety of means such as N2 adsorption, field emission scanning electron microscope, transmission electron microscope, Raman spectroscopy. The results showed that the carbons have large surface area and developed porosity with micro-meso hierarchical pore texture. As evidenced by electrochemical measurements, the specific capacitance of the carbons can reach up to 296 F g−1. More importantly, the carbons can maintain a high capacitance of up to 152 F g−1 at a very high current density of 30 A g−1, highlighting the promise of the carbons for high power applications

  20. Characterization of activated carbon produced from urban organic waste

    Abdul Gani Haji

    2013-10-01

    Full Text Available The difficulties to decompose organic waste can be handled naturally by pyrolisis so it can  decomposes quickly that produces charcoal as the product. This study aims to investigate the characteristics of activated carbon from urban organic waste. Charcoal results of pyrolysis of organic waste activated with KOH 1.0 M at a temperature of 700 and 800oC for 60 to 120 minutes. Characteristics of activated carbon were identified by Furrier Transform Infra Red (FTIR, Scanning Electron Microscopy (SEM, and X-Ray Diffraction (XRD. However, their quality is determined yield, moisture content, ash, fly substances, fixed carbon, and the power of adsorption of iodine and benzene. The identified functional groups on activated carbon, such as OH (3448,5-3436,9 cm-1, and C=O (1639,4 cm-1. In general, the degree and distance between the layers of active carbon crystallites produced activation in all treatments showed no significant difference. The pattern of activated carbon surface topography structure shows that the greater the pore formation in accordance with the temperature increase the more activation time needed. The yield of activated carbon obtained ranged from 72.04 to 82.75%. The results of characterization properties of activated carbon was obtained from 1.11 to 5.41% water, 13.68 to 17.27% substance fly, 20.36 to 26.59% ash, and 56.14 to 62.31% of fixed carbon . Absorption of activated carbon was good enough at 800oC and 120 minutes of activation time, that was equal to 409.52 mg/g of iodine and 14.03% of benzene. Activated carbon produced has less good quality, because only the water content and flying substances that meet the standards.Doi: 10.12777/ijse.5.2.89-94 [How to cite this article: Haji, A.G., Pari, G., Nazar, M., and Habibati.  (2013. Characterization of activated carbon produced from urban organic waste . International Journal of Science and Engineering, 5(2,89-94. Doi: 10.12777/ijse.5.2.89-94

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

    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.

  2. Adsorption of Gaseous Methyl Iodide by Active Carbons

    The impregnation of active carbons is known to be a useful means of improving the ability of these carbons to retain methyl iodide which might be formed during the accidental release of fission products from a reactor. Some basic work was done on both impregnated and unimpregnated materials, which involved: (a) the texture: (b) the reaction of Mel with the impregnants; (c) the adsorption of Mel on the carbons under dry and wet conditions at different temperatures. It was found that the carbons are highly microporous. A large part of this porosity disappears on impregnation with organic amine; These impregnants react chemically with the methyl iodide, which is thereby fixed on the carbon. For carbon which is impregnated with KI, a rapid exchange reaction takes place between the methyl iodide and KI under both dry and wet conditions. Consequently most of the iodine activity can be removed from the gas. (author)

  3. Evaluation of the plasma quality after filtration

    M Mahmoodian Shooshtari; Mousavi Hosseini, K.

    2010-01-01

    "n  "n "nBackground and the purpose of the study: The quality of some of the human plasma derived drugs such as coagulation factor VIII and coagulation factor IX which can be used for the treatment of hemophilia A and B, depends on their activity which may be affected by filtration. In this study the quality of plasma with respect to coagulation factors FVII, FVIII, FIX, FV, FXI, Fibrinogen, antithrombin III, anti-plasmin and antitrypsin activities obtained after plasm...

  4. Andersen Filtration and Hard Lefschetz

    Soergel, Wolfgang

    2006-01-01

    On the space of homomorphisms from a Verma module to an indecomposable tilting module of the BGG-category O we define a natural filtration following Andersen and establish a formula expressing the dimensions of the filtration steps in terms of coefficients of Kazhdan-Lusztig polynomials.

  5. Air filtration in HVAC systems

    Ginestet, Alain; Tronville, Paolo; Hyttinen, Marko

    2010-01-01

    Air filtration Guidebook will help the designer and user to understand the background and criteria for air filtration, how to select air filters and avoid problems associated with hygienic and other conditions at operation of air filters. The selection of air filters is based on external conditions such as levels of existing pollutants, indoor air quality and energy efficiency requirements.

  6. Contribution from carbon and sulphur isotopes to the evaluation of biogeochemical processes in groundwater systems controlled by river bank filtration: An example from the Torgau aquifer (Saxony, Germany)

    Sulphur and carbon isotopes were used to reveal flow processes and chemical reactions within an aquifer system partially controlled by river bed infiltration. The investigation site, located at the Elbe river, is the most important water supply area of Saxony. An arrangement of about 40 groundwater sampling points, screened in five or three depth levels within a section crossing the Elbe, was used to describe the situation in the Quaternary aquifer. Using 34S (SO4) and 13C (DIC) as tracers, an improved understanding of the flow pattern has been obtained, especially regarding the penetration of groundwater into the aquifer zone below the Elbe bed. Furthermore, groundwater and Elbe water show different isotope signatures. Depletion of 34S in the area between the Elbe and the production wells is attributed to the oxidation of pyritic sulphur. The measured radiocarbon concentrations of groundwater fulvic acids suggest that less than 50% of the DOC originates from old sedimentary organic carbon (SOC) sources in the aquifer. 14C decrease along the flow path from the Elbe to the captation facilities has been observed and is proposed as being due to a simultaneous degradation of Elbe DOC and dissolution of old SOC from the penetrated aquifer. The unusual chemical and isotopic composition of groundwater near the edge of the investigated profile is interpreted as a local influence of ascending waters coming from Zechstein formations and penetrating the overlaying Triassic and Tertiary layers via tectonic faults or geological windows. (author)

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

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

    2016-10-01

    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. PMID:27214000

  8. High Surface Area of Nano Pores Activated Carbon Derived From Agriculture Waste

    In this study, the high surface area of nano pores activated carbon rice husk originated from local biomass was investigated. The comparison in terms of surface area, porosity and behavior in electrochemical analysis with commercial activated carbon was studied in details. The nano pores activated carbon rice husk was synthesis using consecutive of carbonization and activation under purified nitrogen and carbon dioxide purge. Interestingly, the surface area and capacity of the nano pores activated carbon rice indicated higher in comparison to commercial activated carbon. This indicated that the nano pores activated carbon has potential to be developed further as an alternative material in reducing suspension on commercial activated carbon. (author)

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

    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

  10. Effects of sediment-associated extractable metals, degree of sediment grain sorting, and dissolved organic carbon upon cryptosporidium parvum removal and transport within riverbank filtration sediments, Sonoma County, California

    Metge, D.W.; Harvey, R.W.; Aiken, G.R.; Anders, R.; Lincoln, G.; Jasperse, J.; Hill, M.C.

    2011-01-01

    Oocysts of the protozoan pathogen Cryptosporidium parvum are of particular concern for riverbank filtration (RBF) operations because of their persistence, ubiquity, and resistance to chlorine disinfection. At the Russian River RBF site (Sonoma County, CA), transport of C. parvum oocysts and oocyst-sized (3 ??m) carboxylate-modified microspheres through poorly sorted (sorting indices, ??1, up to 3.0) and geochemically heterogeneous sediments collected between 2 and 25 m below land surface (bls) were assessed. Removal was highly sensitive to variations in both the quantity of extractable metals (mainly Fe and Al) and degree of grain sorting. In flow-through columns, there was a log-linear relationship (r2 = 0.82 at p organic carbon (DOC) reduced ?? for oocysts by 4-5 fold. The highly reactive hydrophobic organic acid (HPOA) fraction was particularly effective in re-entraining sediment-attached microspheres. However, the transport-enhancing effects of the riverine DOC did not appear to penetrate very deeply into the underlying sediments, judging from high ?? values (???1.0) observed for oocysts being advected through unamended sediments collected at ???2 m bls. This study suggests that in evaluating the efficacy of RBF operations to remove oocysts, it may be necessary to consider not only the geochemical nature and size distribution of the sediment grains, but also the degrees of sediment sorting and the concentration, reactivity, and penetration of the source water DOC. ?? 2011 American Chemical Society.

  11. Adsorption of light alkanes on coconut nanoporous activated carbon

    K. S. Walton

    2006-12-01

    Full Text Available This paper presents experimental results for adsorption equilibrium of methane, ethane, and butane on nanoporous activated carbon obtained from coconut shells. The adsorption data were obtained gravimetrically at temperatures between 260 and 300K and pressures up to 1 bar. The Toth isotherm was used to correlate the data, showing good agreement with measured values. Low-coverage equilibrium constants were estimated using virial plots. Heats of adsorption at different loadings were also estimated from the equilibrium data. Adsorption properties for this material are compared to the same properties for BPL activated carbon and BAX activated carbon.

  12. Tribological Characteristics of Chromium-active Carbon Electroplated Composite Coatings

    GUKa-fi; HUAMeng; Yi-min

    2004-01-01

    A process of chromium electroplating using a standard bath with additives and active carbon particles was reported, and the tribological behaviors of the composite coatings using the pin-on-disk tester and the table wear tester were i nvestig(aed. Experimental results indicate that the electroplated chromium-active carbon composite coatings exhibited the low friction coefficient anti excellent anti-wear properties whets coffered with the normal chromium electroplated ones. The formation of active carbon particles within the chromium matrices can be explained by SEM analysis and the mechanis of wear resistance of the composite coatings were studied.

  13. HYDROGEN SULFIDE ADSORPTION BY ALKALINE IMPREGNATED COCONUT SHELL ACTIVATED CARBON

    HUI SUN CHOO; LEE CHUNG LAU; ABDUL RAHMAN MOHAMED; KEAT TEONG LEE

    2013-01-01

    Biogas is one type of renewable energy which can be burnt to produce heat and electricity. However, it cannot be burnt directly due to the presence of hydrogen sulfide (H2S) which is highly corrosive to gas engine. In this study, coconut shell activated carbon (CSAC) was applied as a porous adsorbent for H2S removal. The effect of amount of activated carbon and flow rate of gas stream toward adsorption capacity were investigated. Then, the activated carbons were impregnated by three types of ...

  14. Nickel adsorption by sodium polyacrylate-grafted activated carbon

    Ewecharoen, A. [Division of Biotechnology, School of Bioresources and Technology, King Mongkut' s University of Technology Thonburi, 83 Moo 8 Thakham, Bangkhuntien, Bangkok 10150 (Thailand); Thiravetyan, P., E-mail: paitip@hotmail.com [Division of Biotechnology, School of Bioresources and Technology, King Mongkut' s University of Technology Thonburi, 83 Moo 8 Thakham, Bangkhuntien, Bangkok 10150 (Thailand); Wendel, E.; Bertagnolli, H. [Institut fuer Physikalische Chemie, Universitaet Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart (Germany)

    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{sup -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.

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

    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. PMID:19576692

  16. Grafting of activated carbon cloths for selective adsorption

    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.

  17. Treatment of micropollutants in municipal wastewater: ozone or powdered activated carbon?

    Margot, Jonas; Kienle, Cornelia; Magnet, Anoÿs; Weil, Mirco; Rossi, Luca; de Alencastro, Luiz Felippe; Abegglen, Christian; Thonney, Denis; Chèvre, Nathalie; Schärer, Michael; Barry, D A

    2013-09-01

    Many organic micropollutants present in wastewater, such as pharmaceuticals and pesticides, are poorly removed in conventional wastewater treatment plants (WWTPs). To reduce the release of these substances into the aquatic environment, advanced wastewater treatments are necessary. In this context, two large-scale pilot advanced treatments were tested in parallel over more than one year at the municipal WWTP of Lausanne, Switzerland. The treatments were: i) oxidation by ozone followed by sand filtration (SF) and ii) powdered activated carbon (PAC) adsorption followed by either ultrafiltration (UF) or sand filtration. More than 70 potentially problematic substances (pharmaceuticals, pesticides, endocrine disruptors, drug metabolites and other common chemicals) were regularly measured at different stages of treatment. Additionally, several ecotoxicological tests such as the Yeast Estrogen Screen, a combined algae bioassay and a fish early life stage test were performed to evaluate effluent toxicity. Both treatments significantly improved the effluent quality. Micropollutants were removed on average over 80% compared with raw wastewater, with an average ozone dose of 5.7 mg O3 l(-1) or a PAC dose between 10 and 20 mg l(-1). Depending on the chemical properties of the substances (presence of electron-rich moieties, charge and hydrophobicity), either ozone or PAC performed better. Both advanced treatments led to a clear reduction in toxicity of the effluents, with PAC-UF performing slightly better overall. As both treatments had, on average, relatively similar efficiency, further criteria relevant to their implementation were considered, including local constraints (e.g., safety, sludge disposal, disinfection), operational feasibility and cost. For sensitive receiving waters (drinking water resources or recreational waters), the PAC-UF treatment, despite its current higher cost, was considered to be the most suitable option, enabling good removal of most micropollutants

  18. Solid-state drawing of post-consumer isotactic poly(propylene): Effect of melt filtration and carbon black on structural and mechanical properties.

    Luijsterburg, B J; Jobse, P S; Spoelstra, A B; Goossens, J G P

    2016-08-01

    Post-consumer plastic waste obtained via mechanical recycling is usually applied in thick-walled products, because of the low mechanical strength due to the presence of contaminants. In fact, sorted post-consumer isotactic poly(propylene) (i-PP) can be considered as a blend of 95% i-PP and 5% poly(ethylene), with traces of poly(ethylene terephthalate) (PET). By applying a treatment such as solid-state drawing (SSD) after melt extrusion, the polymer chains can be oriented in one direction, thereby improving the stiffness and tensile strength. In this research, molecular processes such as crystal break-up and chain orientation of these complex blends were monitored as a function of draw ratio. The melt filter mesh size - used to exclude rigid PET particles - and the addition of carbon black (CB) - often added for coloration in the recycling industry - were varied to investigate their influence on the SSD process. This research shows that despite the blend complexity, the molecular processes during SSD compare to virgin i-PP and that similar draw ratios can be obtained (λmax=20), albeit at reduced stiffness and strength as a result of the foreign polymers present in post-consumer i-PP. It is observed that the process stability improves with decreasing mesh size and that higher draw ratios can be obtained. The addition of carbon black, which resides in the dispersed PE phase, also stabilizes the SSD process. Compared to isotropic post-consumer i-PP, the stiffness can be improved by a factor 10 to over 11GPa, while the tensile strength can be improved by a factor 15-385MPa, which is approx. 70% of the maximum tensile strength achieved for virgin i-PP. PMID:27216728

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

    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

  20. TESTING GUIDELINES FOR TECHNETIUM-99 ADSORPTION ON ACTIVATED CARBON

    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

  1. Intact tropical forests, new evidence they uptake carbon actively

    2009-03-01

    Full Text Available According to a paper recently published on Nature, tropical forests play as active carbon sink, absorbing 1.3·109 tons of carbon per year on a global scale. Functional interpretation is not clear yet, but a point is quite easy to realize: tropical forests accumulate and contain more carbon than any other vegetation cover and, if their disruption goes on at current rates, these ecosystems could revert to be a “carbon bomb”, releasing huge amount of CO2 to the atmosphere.

  2. Adsorption of uranium from crude phosphoric acid using activated carbon

    The adsorption of uranium from crude phosphoric acid has been investigated using conventional activated carbons. It was found that treatment with nitric acid oxidized the surface of activated carbon and significantly increased the adsorption capacity for uranium in acidic solutions. The parameters that affect the uranium(VI) adsorption, such as contact time, solution pH, initial uranium(VI) concentration, and temperature, have been investigated. Equilibrium data were fitted to a simplified Langmuir and Freundlich isotherms for the oxidized samples which indicate that the uranium adsorption onto the activated carbon fitted well with Langmuir isotherm than Freundlich isotherm. Equilibrium studies evaluate the theoretical capacity of activated carbon to be 45.24 g kg-1. (author)

  3. Adsorptive preconcentration of rareearth oxine complexes onto activated carbon

    This paper describes a method for the determination of traces of rare earth using energy dispersive x-ray fluorescence spectrometry (EDXRF) after preconcentration of their oxine complexes onto activated carbon. Various parameters that influence adsorptive preconcentration of rare earth onto activated carbon viz. pH, amounts of activated carbon and oxine, time of stirring and aqueous phase volume were systematically studied. A numerical method based on simple least square procedure using fifth order polynomial with 25 consecutive values was developed for smoothing and differentiation of EDXRF data which was previously digitized and averaged. First order derivative EDXRF in conjunction with adsorptive preconcentration on activated carbon enables one to determine as low as 10 ppb of each individual rare earth elements

  4. A combined process of activated carbon adsorption, ion exchange resin treatment and membrane concentration for recovery of dissolved organics in pre-hydrolysis liquor of the kraft-based dissolving pulp production process.

    Shen, Jing; Kaur, Ishneet; Baktash, Mir Mojtaba; He, Zhibin; Ni, Yonghao

    2013-01-01

    To recover dissolved organics in pre-hydrolysis liquor (PHL) of the kraft-based dissolving pulp production process, a new combined process concept of sequential steps of activated carbon adsorption, ion exchange resin treatment, and membrane concentration, was proposed. The removal of lignin in the PHL was achieved in the activated carbon adsorption step, which also facilitates the subsequent operations, such as the membrane filtration and ion exchange resin treatment. The ion exchange resin treatment resulted in the removal/concentration of acetic acid, which opens the door for acetic acid recovery. The membrane filtration is to recover/concentrate the dissolved sugars. The combined process resulted in the production of PHL-based concentrate with relatively high concentration of hemicellulosic sugars, i.e., 22.13%. PMID:23131623

  5. Functionalized Activated Carbon Derived from Biomass for Photocatalysis Applications Perspective

    Samira Bagheri

    2015-01-01

    Full Text Available This review highlighted the developments of safe, effective, economic, and environmental friendly catalytic technologies to transform lignocellulosic biomass into the activated carbon (AC. In the photocatalysis applications, this AC can further be used as a support material. The limits of AC productions raised by energy assumption and product selectivity have been uplifted to develop sustainable carbon of the synthesis process, where catalytic conversion is accounted. The catalytic treatment corresponding to mild condition provided a bulk, mesoporous, and nanostructure AC materials. These characteristics of AC materials are necessary for the low energy and efficient photocatalytic system. Due to the excellent oxidizing characteristics, cheapness, and long-term stability, semiconductor materials have been used immensely in photocatalytic reactors. However, in practical, such conductors lead to problems with the separation steps and loss of photocatalytic activity. Therefore, proper attention has been given to develop supported semiconductor catalysts and certain matrixes of carbon materials such as carbon nanotubes, carbon microspheres, carbon nanofibers, carbon black, and activated carbons have been recently considered and reported. AC has been reported as a potential support in photocatalytic systems because it improves the transfer rate of the interface charge and lowers the recombination rate of holes and electrons.

  6. The investment funds in carbon actives: state of the art

    Since the beginning in 1999 of the first funds by the World Bank, the purchase mechanisms of carbon actives, developed and reached today more than 1,5 milliards of euros. The landscape is relatively concentrated, in spite of the numerous initiatives. The author presents the situation since 1999, the importance of the european governmental investors, the purchase mechanisms management and an inventory of the carbon actives purchases. (A.L.B.)

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

    Gonzalez-Garcia, P., E-mail: pegonzal@quim.ucm.es [Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutense, E-28040, Madrid (Spain); Centeno, T.A. [Instituto Nacional del Carbon-CSIC, Apartado 73, E-33080 Oviedo (Spain); Urones-Garrote, E. [Centro Nacional de Microscopia Electronica, Universidad Complutense, E-28040, Madrid (Spain); Avila-Brande, D.; Otero-Diaz, L.C. [Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Universidad Complutense, E-28040, Madrid (Spain)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Activated carbons were produced by KOH activation at 700 Degree-Sign C. Black-Right-Pointing-Pointer The observed nanostructure consists of highly disordered graphene-like layers with sp{sup 2} bond content Almost-Equal-To 95%. Black-Right-Pointing-Pointer Textural parameters show high surface area ( Almost-Equal-To 1000 m{sup 2}/g) and pore width of 1.3-1.8 nm. Black-Right-Pointing-Pointer Specific capacitance reaches values as high as 161 F/g. - Abstract: Low cost activated carbons have been produced via chemical activation, by using KOH at 700 Degree-Sign C, from the bamboo species Guadua Angustifolia and Bambusa Vulgaris Striata and the residues from shells of the fruits of Castanea Sativa and Juglans Regia as carbon precursors. The scanning electron microscopy micrographs show the conservation of the precursor shape in the case of the Guadua Angustifolia and Bambusa Vulgaris Striata activated carbons. Transmission electron microscopy analyses reveal that these materials consist of carbon platelet-like particles with variable length and thickness, formed by highly disordered graphene-like layers with sp{sup 2} content Almost-Equal-To 95% and average mass density of 1.65 g/cm{sup 3} (25% below standard graphite). Textural parameters indicate a high porosity development with surface areas ranging from 850 to 1100 m{sup 2}/g and average pore width centered in the supermicropores range (1.3-1.8 nm). The electrochemical performance of the activated carbons shows specific capacitance values at low current density (1 mA/cm{sup 2}) as high as 161 F/g in the Juglans Regia activated carbon, as a result of its textural parameters and the presence of pseudocapacitance derived from surface oxygenated acidic groups (mainly quinones and ethers) identified in this activated carbon.

  8. Microwave absorbing properties of activated carbon fibre polymer composites

    Tianchun Zou; Naiqin Zhao; Chunsheng Shi; Jiajun Li

    2011-02-01

    Microwave absorption of composites containing activated carbon fibres (ACFs) was investigated. The results show that the absorptivity greatly depends on increasing ACF content in the absorbing layer, first increasing and then decreasing. When the content is 0.76 wt.%, the bandwidth below −10dB is 12.2 GHz. Comparing the absorption characteristics of the ACF composite with one containing unactivated fibres, it is found that carbon fibre activation increases the absorption of the composite.

  9. Development and Environmental Applications of Activated Carbon Cloths

    Ana Lea Cukierman

    2013-01-01

    Activated carbon cloths have received growing attention because they offer comparative advantages over the traditional powdered or granular forms of this well-known adsorbent, providing further potential uses for technological innovations in several fields. The present article provides an overview of research studies and advances concerned with the development of activated carbon cloths and their use as adsorbent in environmental applications, mostly reported in the last years. The influence ...

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

    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.

  11. Synthesis of carbon nanofibers on impregnated powdered activated carbon as cheap substrate

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

    2016-01-01

    The catalysis and characterization of carbon nanofibers (CNFs) composite are reported in this work. Carbon nanofibers were produced on oil palm shell powdered activated carbon (PAC), which was impregnated with nickel. Chemical Vapor Deposition (CVD) of C2H2 was used in the presence of hydrogen at ∼650 °C. The flow rates of carbon source and hydrogen were fixed. The CNFs formed directly on the surface of the impregnated PAC. Variable weight percentages (1%, 3%, 5%, 7% and 9%) of the catalyst s...

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

    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.

  13. Removal of dye by immobilised photo catalyst loaded activated carbon

    The ability of activated carbon to adsorb and titanium dioxide to photo degrade organic impurities from water bodies is well accepted. Combination of the two is expected to enhance the removal efficiency due to the synergistic effect. This has enabled activated carbon to adsorb more and at the same time the lifespan of activated carbon is prolonged as the workload of removing organic pollutants is shared between activated carbon and titanium dioxide. Immobilisation is selected to avoid unnecessary filtering of adsorbent and photo catalyst. In this study, mixture of activated carbon and titanium dioxide was immobilised on glass slides. Photodegradation and adsorption studies of Methylene Blue solution were conducted in the absence and presence of UV light. The removal efficiency of immobilised TiO2/ AC was found to be two times better than the removal by immobilised AC or immobilised TiO2 alone. In 4 hours and with the concentration of 10 ppm, TiO2 loaded activated carbon prepared from 1.5 g/ 15.0 mL suspension produced 99.50 % dye removal. (author)

  14. Nanoporous activated carbon cloth for capacitive deionization of aqueous solution

    Oh, Han-Jun [Department of Materials Science, Hanseo University, Seosan, 352-820 (Korea, Republic of); Lee, Jong-Ho [Department of Chemistry, Hanseo University, Seosan, 352-820 (Korea, Republic of); Ahn, Hong-Joo [Korea Atomic Energy Research Institute, Daejeon, 305-600 (Korea, Republic of); Jeong, Yongsoo [Korea Institute of Machinery and Materials, Changwon, 641-010 (Korea, Republic of); Kim, Young-Jig [Department of Metallurgical Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Chi, Choong-Soo [School of Advanced Materials Engineering, Kookmin University, Seoul, 136-702 (Korea, Republic of)]. E-mail: cschi@kookmin.ac.kr

    2006-09-25

    Activated nanostructured-carbon cloths with a high ratio of surface area to volume are used as electrode for capacitive deionization. The electrochemical properties on capacitive deionization for NaCl solution have been investigated to improve efficiency of capacitive deionization properties from aqueous solution, employing chemical surface-modification by etching in alkaline and acidic solution. The removal efficiency of inorganic salts of activated carbon cloths by chemical modification significantly increased. Specially the carbon cloth surface modified in HNO{sub 3} showed an effect of improvement in the CDI efficiency due to not only ion adsorption by an electric double layer, but also electron transfer by Faradaic reaction.

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

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

    2005-05-01

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

  16. Problems of multiphase fluid filtration

    Konovalov, AN

    1994-01-01

    This book deals with a spectrum of problems related to the mathematical modeling of multiphase filtration. Emphasis is placed on an inseparable triad: model - algorithm - computer code. An analysis of new and traditional filtration problems from the point of view of both their numerical implementation and the reproduction of one or another technological characteristics of the processes under consideration is given. The basic principles which underlie the construction of efficient numerical methods taking into account the filtration problems are discussed: non-evolutionary nature, degeneration,

  17. Calculation of Binary Adsorption Equilibria: Hydrocarbons and Carbon Dioxide on Activated Carbon

    Marcussen, Lis; Krøll, A.

    1999-01-01

    Binary adsorption equilibria are calculated by means of a mathematical model for multicomponent mixtures combined with the SPD (Spreading Pressure Dependent) model for calculation of activity coefficients in the adsorbed phase. The model has been applied successfully for the adsorption of binary ...... mixtures of hydrocarbons and carbon dioxide on activated carbons. The model parameters have been determined, and the model has proven to be suited for prediction of adsorption equilibria in the investigated systems....

  18. Adsorption of Acenaphthene unto Activated Carbon Produced from Agricultural Wastes

    F.E. Adelowo

    2012-01-01

    Full Text Available The suitability and the performance of activated carbon produced from flamboyant pod back, milk bush kernel shell and rice husk for the effective removal of acenaphthene from simulated wastewater under the influence of carbonization temperature and initial concentration were investigated. The adsorption capacities of all the activated carbons obtained from the selected raw materials are influenced by increasing carbonization temperature. Activated carbons obtained from rice husk at carbonisation temperature of 600°C had the maximum adsorption capacity (5.554 mg g-1 while carbons produced from milk bush at carbonisation temperature of 300°C had the minimum adsorption capacity (1.386 mg g-1, for the adsorption of acenaphthene from the simulated wastewater. The removal efficiencies of the investigated adsorbents generally rank high and the highest value (80.56% was obtained for the adsorption of acenaphthene by rice husk carbonized at 600°C. Furthermore, the removal efficiencies obtained in the study decreased as the initial concentrations of the adsorbate increased. The four selected isotherm models; Freundlich, Langmuir, Temkin and Dubinin-Radushkevich described well the equilibrium adsorption of acenaphthene unto activated carbon derived from Flamboyant pod bark, milk bush kernel shell and rice husk. Sequence of suitability of the selected isotherms in the study was Temkin ≈ Freundlich >Dubinin-Radushkevich>Langmuir for adsorption of acenaphthene. It therefore shows that Temkin isotherm is the most suitable model for fitting experimental data obtained from adsorption of acenaphthene from simulated wastewater unto activated carbon produced from Flamboyant pod bark, milk bush kernel shell and rice husk.

  19. Evaluation of Powdered Activated Carbon Efficiency in Removal of Dissolved Organic Carbon inWater Treatment

    G.R Bonyadi nejad; R Hadian; M Saadani; B Jaberian; M.M Amin; A Khodabakhshi

    2010-01-01

    "n "nBackgrounds and Objectives: Powdered Activated$ carbon is known as a suitable absorbent for organic materials. The aim of this research is evaluation of Powdered Activated-Carbon (PAC) efficiency in removal of Dissolved Organic Carbon (DOC) in water treatment in Isfahan."nMaterials and Methods : The increase of PAC for DOC reduction has done in three paths in the Isfahan water treatment plant (WTP). These paths including: 1) Intake up to entrance of WTP 2) Intake to exit ofWTP 3) Between...

  20. Evaluation of Powdered Activated Carbon Efficiency in Removal of Dissolved Organic Carbon inWater Treatment

    G.R Bonyadi nejad

    2010-07-01

    Full Text Available "n "nBackgrounds and Objectives: Powdered Activated$ carbon is known as a suitable absorbent for organic materials. The aim of this research is evaluation of Powdered Activated-Carbon (PAC efficiency in removal of Dissolved Organic Carbon (DOC in water treatment in Isfahan."nMaterials and Methods : The increase of PAC for DOC reduction has done in three paths in the Isfahan water treatment plant (WTP. These paths including: 1 Intake up to entrance of WTP 2 Intake to exit ofWTP 3 Between entrance and exit of waterworks. The paths were simulated by the Jar test system. Then DOC and UV254 absorption were analyzed and SUVA parameter for samples and activated-carbon adsorption isotherm was calculated."nResults: The injected PAC doses of 20,40,60,80 and 100 mg/l caused decreasing in DOC and UV254 absorption in every sample in all paths. The average of this decrease, from intake to WTP.s exit (second path was the greatest 69.8± 3.9%and the commonWTP process had capability of removing 35% of DOC. The first path also showed that PAC can reduce 33± 2% DOC of raw water by itself. Activated-carbon absorption results were adhered from Freundlich adsorption isotherm."nConclusion: In the third path therewas lessDOCremoval efficiency than exceptedwhen Activated- Carbon injected in rapid mixed basin with coagulant. Powdered activated carbon porosity reduction due to effect of coagulant can be the reason for this issue.Also according to different paths, the point of intake is more suitable for powdered activated carbon addition.

  1. Adsorption of dissolved natural organic matter by modified activated carbons.

    Cheng, Wei; Dastgheib, Seyed A; Karanfil, Tanju

    2005-06-01

    Adsorption of dissolved natural organic matter (DOM) by virgin and modified granular activated carbons (GACs) was studied. DOM samples were obtained from two water treatment plants before (i.e., raw water) and after coagulation/flocculation/sedimentation processes (i.e., treated water). A granular activated carbon (GAC) was modified by high temperature helium or ammonia treatment, or iron impregnation followed by high temperature ammonia treatment. Two activated carbon fibers (ACFs) were also used, with no modification, to examine the effect of carbon porosity on DOM adsorption. Size exclusion chromatography (SEC) and specific ultraviolet absorbance (SUVA(254)) were employed to characterize the DOMs before and after adsorption. Iron-impregnated (HDFe) and ammonia-treated (HDN) activated carbons showed significantly higher DOM uptakes than the virgin GAC. The enhanced DOM uptake by HDFe was due to the presence of iron species on the carbon surface. The higher uptake of HDN was attributed to the enlarged carbon pores and basic surface created during ammonia treatment. The SEC and SUVA(254) results showed no specific selectivity in the removal of different DOM components as a result of carbon modification. The removal of DOM from both raw and treated waters was negligible by ACF10, having 96% of its surface area in pores smaller than 1 nm. Small molecular weight (MW) DOM components were preferentially removed by ACF20H, having 33% of its surface area in 1--3 nm pores. DOM components with MWs larger than 1600, 2000, and 2700 Da of Charleston raw, Charleston-treated, and Spartanburg-treated waters, respectively, were excluded from the pores of ACF20H. In contrast to carbon fibers, DOM components from entire MW range were removed from waters by virgin and modified GACs. PMID:15927230

  2. Composite electrodes of activated carbon derived from cassava peel and carbon nanotubes for supercapacitor applications

    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.

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

    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

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

    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

  5. Separation of Th from aqueous solutions using activated carbon

    Since the last century, thorium has been extensively used in a variety of applications. These applications produce various gaseous, liquid and solid wastes containing isotopes of thorium. Liquid wastes are freed into the surface or the underground waters of mines. Solid and liquid wastes are also produced during nuclear fuel production. Direct toxicity of thorium is low due to its stability at ambient temperatures; however thorium fine powder is self-ignitable to thorium oxide. When thorium nitrate enters living organisms it is mainly localized in liver, spleen and marrow and it precipitates in a hydroxide form. Investigations concerning the removal or minimization of the thorium concentration in the waste waters are of considerable importance environmental point of view. Adsorption is an important technique in separation and purification processes. Among many types of adsorbent materials, activated carbons are the most widely used, because of their large adsorptive capacity and low cost. Activated carbons are unique adsorbents because of their extended surface area, microporous structure, high adsorption capacity and high degree of surface reactivity. Separation and purification processes based on adsorption technique are also important in nuclear industry where activated carbon is often used for the separation of metal ions from solutions, due to its selective adsorption, high radiation stability and high purity. The activated carbons used in this study were prepared by the chemical activation of acrylic fiber. The chemical composition of acrylic fiber is a copolymer of acrylonitrile-vinyl acetate is called also poliacrylonitryl fiber. The effects of carbonization conditions resulting activated carbon were examined. Precursor/activating agent (KOH and ZnCl2) ratio and carbonization temperature were investigated for the preparation of adsorbent. Adsorption experiments were carried out by a batch technique. The adsorption of thorium was studied as a function of

  6. Health Benefits of Particle Filtration

    Fisk, William J.

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percent age improvement in health outcomes is typically modest, for example, 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  7. Health Benefits of Particle Filtration

    Fisk, William J.

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, e.g., 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

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

    Contescu, Cristian I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gallego, Nidia C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Thibaud-Erkey, Catherine [United Technologies Research Center (UTRC), East Hartford, CT (United States); Karra, Reddy [United Technologies Research Center (UTRC), East Hartford, CT (United States)

    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.

  9. Porous texture evolution in Nomex-derived activated carbon fibers.

    Villar-Rodil, S; Denoyel, R; Rouquerol, J; Martínez-Alonso, A; Tascón, J M D

    2002-08-01

    In the present work, the textural evolution of a series of activated carbon fibers with increasing burn-off degree, prepared by the pyrolysis and steam activation of Nomex aramid fibers, is followed by measurements of physical adsorption of N(2) (77 K) and CO(2) (273 K) and immersion calorimetry into different liquids (dichloromethane, benzene, cyclohexane). The immersion calorimetry results are discussed in depth, paying special attention to the choice of the reference material. The activated carbon fibers studied possess an essentially homogeneous microporous texture, which suggests that these materials may be applied in gas separation, either directly or with additional CVD treatment. PMID:16290775

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

    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. PMID:15461177

  11. Production of activated carbons from coffee endocarp by CO2 and steam activation

    In this work the use of coffee endocarp as precursor for the production of activated carbons by steam and CO2 was studied. Activation by both methods produces activated carbons with small external areas and microporous structures having very similar mean pore widths. The activation produces mainly primary micropores and only a small volume of larger micropores. The CO2 activation leads to samples with higher BET surface areas and pore volumes when compared with samples produced by steam activation and with similar burn-off value. All the activated carbons produced have basic characteristics with point of zero charge between 10 and 12. By FTIR it was possible to identify the formation on the activated carbon's surface of several functional groups, namely ether, quinones, lactones, ketones, hydroxyls (free and phenol); pyrones and Si-H bonds. (author)

  12. Production of activated carbons from coffee endocarp by CO{sub 2} and steam activation

    Nabais, Joao M. Valente; Nunes, Pedro; Carrott, Peter J.M.; Ribeiro Carrott, M. Manuela L. [Centro de Quimica de Evora and Departamento de Quimica, Universidade de Evora, Rua Romao Ramalho no. 59, 7000-671 Evora (Portugal); Garcia, A. Macias; Diaz-Diez, M.A. [Universidad de Extremadura, Avda. de Elvas, s/n 06071 Badajoz (Spain)

    2008-03-15

    In this work the use of coffee endocarp as precursor for the production of activated carbons by steam and CO{sub 2} was studied. Activation by both methods produces activated carbons with small external areas and microporous structures having very similar mean pore widths. The activation produces mainly primary micropores and only a small volume of larger micropores. The CO{sub 2} activation leads to samples with higher BET surface areas and pore volumes when compared with samples produced by steam activation and with similar burn-off value. All the activated carbons produced have basic characteristics with point of zero charge between 10 and 12. By FTIR it was possible to identify the formation on the activated carbon's surface of several functional groups, namely ether, quinones, lactones, ketones, hydroxyls (free and phenol); pyrones and Si-H bonds. (author)

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

    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

  14. Filtration and compression of organic materials

    Christensen, Morten Lykkegaard; Keiding, Kristian

    The conventional filtration theory has been based on filtrations of incompressible particles such as anatase, kaolin and clay. The filtration models have later been used for organic slurries but can often not explain the observed experimental data. At constant pressure, the filtrate volume does not...

  15. Direct filtration of water from Altinapa Dam by dual media filters

    Burdurlu, Y.; Aydin, M.E. [Selcuk University, Konya (Turkey). Dept. of Environmental Engineering

    1999-05-01

    In this research three laboratory scale model filters were employed to evaluate the performance of dual media filters. The model filters had sand, anthracite coal over sand and granular activated carbon over sand as filter media. Water samples from influent and filtrate of each filter column were analyzed to determine the performance of filters. Turbidity, color, organic matters and bacteria count analyses of water samples were carried out. According to the results of this research dual media filters performed better compared to the single media filter in terms of head loss development and hence were able to operate longer.

  16. ADSORPTION CHARACTERISTICS OF L-HISTIDINE ON ACTIVE CARBON

    2005-01-01

    Adsorption properties of L-histidine on active carbon were studied in the paper, which are affected by the main parameters, such as the quantity percent of active carbon, pH value of the solution, the time of adsorption equilibrium and adsorption temperature. The results indicate that adsorption equilibrium time of L-his on active carbon is about 80 minutes. With the increasing of the quantity percent of active carbon, the adsorbance of L-his decreases sharply, and increases lighter after that. When the quantity percent of active carbon is 10%, the adsorbance reaches the minimum.pH value of solution and extraction temperature have great affection on the adsorption. When the pH value is higher or lower than the pI of L-his, the adsorbance is small, even zero. It is proven that the experimental equilibrium data which are obtained under the conditions of 80 ℃and pH=1.0, are fitted with the Freundlich equation: q=2.5914c0.8097. The results can provide certain references in L-his adsorption process of industrial operation.

  17. Impact of biological filtrations for organic micropollutants and polyfluoroalkyl substances removal from secondary effluent.

    Pramanik, Biplob Kumar; Pramanik, Sagor Kumar; Suja, Fatihah

    2016-08-01

    The impact of biological activated carbon (BAC), sand filtration (SF) and biological aerated filter (BAF) for removal of the selected organic micropollutants and polyfluoroalkyl substances (PFASs) from secondary effluent was studied. BAC led to greater removal of dissolved organic carbon (43%) than BAF (30%) which in turn was greater than SF (24%). All biological filtration systems could effectively remove most of the selected organic micropollutants, and there was a greater removal of these micropollutants by BAC (76-98%) than BAF (70-92%) or SF (68-90%). It was found that all treatment was effective for removal of the hydrophobic (log D > 3.2) and readily biodegradable organic micropollutants. The major mechanism for the removal of these molecules was biodegradation by the micro-organism and sorption by the biofilm. Compared to organic micropollutants removal, there was a lower removal of PFASs by all treatments, and BAF and SF had a considerably lower removal than BAC treatment. The better removal for all molecule types by BAC was due to additional adsorption capacity by the activated carbon. This study demonstrated that the BAC process was most effective in removing organic micropollutants present in the secondary effluent. PMID:26695189

  18. Bisphenol A removal from water by activated carbon. Effects of carbon characteristics and solution chemistry.

    Bautista-Toledo, I; Ferro-García, M A; Rivera-Utrilla, J; Moreno-Castilla, C; Vegas Fernández, F J

    2005-08-15

    The present study aimed to analyze the behavior of different activated carbons in the adsorption and removal of bisphenol A (2-2-bis-4-hydroxypheniyl propane) from aqueous solutions in order to identify the parameters that determine this process. Two commercial activated carbons and one prepared in our laboratory from almond shells were used; they were texturally and chemically characterized, obtaining the surface area, pore size distribution, mineral matter content, elemental analysis, oxygen surface groups, and pH of the point of zero charge (pH(PZC)), among other parameters. Adsorption isotherms of bisphenol A and adsorption capacities were obtained. The capacity of the carbons to remove bisphenol A was related to their characteristics. Thus, the adsorption of bisphenol A on activated carbon fundamentally depends on the chemical nature of the carbon surface and the pH of the solution. The most favorable experimental conditions for this process are those in which the net charge density of the carbon is zero and the bisphenol A is in molecular form. Under these conditions, the adsorbent-adsorbate interactions that govern the adsorption mechanism are enhanced. Influences of the mineral matter present in the carbon samples and the solution chemistry (pH and ionic strength) were also analyzed. The presence of mineral matter in carbons reduces their adsorption capacity because of the hydrophilic nature of the matter. The presence of electrolytes in the solution favor the adsorption process because of the screening effect produced between the positively charged carbon surface and the bisphenol A molecules, with a resulting increase in adsorbent-adsorbate interactions. PMID:16173588

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

    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. PMID:26257348

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

    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 deg. C are 12.2 and 39.56 mg/g, respectively. Cr(III) adsorption increased with an increase in temperature (10 deg. C: ATFAC-10.97 mg/g, ACF-36.05 mg/g; 40 deg. 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

  1. A General Methodology for Evaluation of Carbon Sequestration Activities and Carbon Credits

    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.

  2. 75 FR 70208 - Certain Activated Carbon From the People's Republic of China: Final Results and Partial...

    2010-11-17

    ... Administrative Review, 74 FR 31690 (July 2, 2009). \\3\\ See Certain Activated Carbon From the People's Republic of... Antidumping Duty Order: Certain Activated Carbon From the People's Republic of China, 72 FR 20988 (April 27... certain activated carbon. Certain activated carbon is a powdered, granular, or pelletized......

  3. Analysis of dynamic and static filtration and determination of MUD cake parameters

    Calcada, L.A.; Scheid, C.M.; Araujo, C.A.O. de [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil). Dept. de Engenharia Quimica], e-mail: calcada@ufrrj.br; Waldmann, A.T.A.; Martins, A.L. [Petroleo Brasileiro S.A. (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2011-07-15

    Drilling operations around the world employ a concept called overbalance. During this process, it is well known that dynamic and static filtration can occur. Thin filter cakes and low fluid-invasion rates are extremely desirable to promote optimal logging conditions and permeability return. The aim of this work was to compare the different behavior between dynamic and static filtration in drilling wells. To investigate the filtration process of Newtonian suspensions, we built a dynamic and static filtration loop with which we acquired experimental filtration volume data as a function of time. The filtration loop included a tank mixer where a Newtonian aqueous calcium carbonate polydisperse suspension was homogenized. The suspension was pumped through tubes to a dynamic or a static filtration cell. We validated a theoretical model based on Darcy's law and on mass conservation proposed by Ferreira and Massarani (2005). That model predicted mud cake buildup and filtrate flow rate for Newtonian suspensions. Relying on both models and the experimental data, filter cake parameters were calculated. We discuss, based on these parameters, the effects of the filtration configuration in dynamic and static modes. Finally, we generalized Ferreira and Massarani's model (2005) for procedures involving non-Newtonian suspensions. This new model can predict dynamic filtration and fluid invasion for non-Newtonian suspensions as drilling fluids. (author)

  4. Generalised Jantzen filtration of Lie superalgebras I

    Su, Yucai; Zhang, R. B.

    2010-01-01

    A Jantzen type filtration for generalised Varma modules of Lie superalgebras is introduced. In the case of type I Lie superalgebras, it is shown that the generalised Jantzen filtration for any Kac module is the unique Loewy filtration, and the decomposition numbers of the layers of the filtration are determined by the coefficients of inverse Kazhdan-Lusztig polynomials. Furthermore, the length of the Jantzen filtration for any Kac module is determined explicitly in terms of the degree of atyp...

  5. On progressive filtration expansion with a process

    Kchia, Younes; Protter, Philip

    2011-01-01

    In this paper we study progressive filtration expansions with cadlag processes. Using results from the weak convergence of sigma fields theory, we first establish a semimartingale convergence theorem. Then we apply it in a filtration expansion with a process setting and provide sufficient conditions for a semimartingale of the base filtration to remain a semimartingale in the expanded filtration. Finally, an application to the expansion of a Brownian filtration with a time reversed diffusion ...

  6. Performance enhancement with powdered activated carbon (PAC) addition in a membrane bioreactor (MBR) treating distillery effluent

    Satyawali, Yamini [TERI University, 10, Institutional Area, Vasant Kunj, New Delhi 110070 (India); Balakrishnan, Malini, E-mail: malinib@teri.res.in [TERI University, 10, Institutional Area, Vasant Kunj, New Delhi 110070 (India); Energy and Resources Institute (TERI), Darbari Seth Block, India Habitat Center, Lodhi Road, New Delhi 110003 (India)

    2009-10-15

    This work investigated the effect of powdered activated carbon (PAC) addition on the operation of a membrane bioreactor (MBR) treating sugarcane molasses based distillery wastewater (spentwash). The 8 L reactor was equipped with a submerged 30 {mu}m nylon mesh filter with 0.05 m{sup 2} filtration area. Detailed characterization of the commercial wood charcoal based PAC was performed before using it in the MBR. The MBR was operated over 200 days at organic loading rates (OLRs) varying from 4.2 to 6.9 kg m{sup -3} d{sup -1}. PAC addition controlled the reactor foaming during start up and enhanced the critical flux by around 23%; it also prolonged the duration between filter cleaning. Operation at higher loading rates was possible and for a given OLR, the chemical oxygen demand (COD) removal was higher with PAC addition. However, biodegradation in the reactor was limited and the high molecular weight compounds were not affected by PAC supplementation. The functional groups on PAC appear to interact with the polysaccharide portion of the sludge, which may reduce its propensity to interact with the nylon mesh.

  7. Performance enhancement with powdered activated carbon (PAC) addition in a membrane bioreactor (MBR) treating distillery effluent

    This work investigated the effect of powdered activated carbon (PAC) addition on the operation of a membrane bioreactor (MBR) treating sugarcane molasses based distillery wastewater (spentwash). The 8 L reactor was equipped with a submerged 30 μm nylon mesh filter with 0.05 m2 filtration area. Detailed characterization of the commercial wood charcoal based PAC was performed before using it in the MBR. The MBR was operated over 200 days at organic loading rates (OLRs) varying from 4.2 to 6.9 kg m-3 d-1. PAC addition controlled the reactor foaming during start up and enhanced the critical flux by around 23%; it also prolonged the duration between filter cleaning. Operation at higher loading rates was possible and for a given OLR, the chemical oxygen demand (COD) removal was higher with PAC addition. However, biodegradation in the reactor was limited and the high molecular weight compounds were not affected by PAC supplementation. The functional groups on PAC appear to interact with the polysaccharide portion of the sludge, which may reduce its propensity to interact with the nylon mesh.

  8. Performance enhancement with powdered activated carbon (PAC) addition in a membrane bioreactor (MBR) treating distillery effluent.

    Satyawali, Yamini; Balakrishnan, Malini

    2009-10-15

    This work investigated the effect of powdered activated carbon (PAC) addition on the operation of a membrane bioreactor (MBR) treating sugarcane molasses based distillery wastewater (spentwash). The 8L reactor was equipped with a submerged 30 microm nylon mesh filter with 0.05 m(2) filtration area. Detailed characterization of the commercial wood charcoal based PAC was performed before using it in the MBR. The MBR was operated over 200 days at organic loading rates (OLRs) varying from 4.2 to 6.9 kg m(-3)d(-1). PAC addition controlled the reactor foaming during start up and enhanced the critical flux by around 23%; it also prolonged the duration between filter cleaning. Operation at higher loading rates was possible and for a given OLR, the chemical oxygen demand (COD) removal was higher with PAC addition. However, biodegradation in the reactor was limited and the high molecular weight compounds were not affected by PAC supplementation. The functional groups on PAC appear to interact with the polysaccharide portion of the sludge, which may reduce its propensity to interact with the nylon mesh. PMID:19467782

  9. CHARACTERIZATION OF ACACIA MANGIUM WOOD BASED ACTIVATED CARBONS PREPARED IN THE PRESENCE OF BASIC ACTIVATING AGENTS

    Mohammed Danish

    2011-06-01

    Full Text Available The aim of this study was to observe the effects of alkaline activating agents on the characteristics, composition, and surface morphology of the designed activated carbons. Activated carbons were prepared by pyrolysis of Acacia mangium wood in the presence of two basic activating agents (calcium oxide and potassium hydroxide. The extent of impregnation ratio of precursor to activating agents was fixed at 2:1(w/w. Prior to pyrolysis, 24 hours soaking was conducted at 348 K. Activation was carried out in a stainless steel capped graphite crucible at 773 K for 2 hours in the absence of purge gas. The burn-off percentage was found to be 70.27±0.93% for CaO activated carbon (COAC and 73.30±0.20% for KOH activated carbon (PHAC. The activating agents had a strong influence on the surface functional groups as well as elemental composition of these activated carbons. Characterization of the activated carbon obtained was performed with field emission scanning electron microscopy (FESEM, energy dispersive X-ray spectroscopy (EDX, Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, and nitrogen adsorption as Brunauer, Emmett and Teller (BET and Dubinin-Radushkevich (DR isotherms.

  10. Ruthenium(0) nanoparticles supported on multiwalled carbon nanotube as highly active catalyst for hydrogen generation from ammonia-borane.

    Akbayrak, Serdar; Ozkar, Saim

    2012-11-01

    Ruthenium(0) nanoparticles supported on multiwalled carbon nanotubes (Ru(0)@MWCNT) were in situ formed during the hydrolysis of ammonia-borane (AB) and could be isolated from the reaction solution by filtration and characterized by ICP-OES, XRD, TEM, SEM, EDX, and XPS techniques. The results reveal that ruthenium(0) nanoparticles of size in the range 1.4-3.0 nm are well-dispersed on multiwalled carbon nanotubes. They were found to be highly active catalyst in hydrogen generation from the hydrolysis of AB with a turnover frequency value of 329 min⁻¹. The reusability experiments show that Ru(0)@MWCNTs are isolable and redispersible in aqueous solution; when redispersed they are still active catalyst in the hydrolysis of AB exhibiting a release of 3.0 equivalents of H₂ per mole of NH₃BH₃ and preserving 41% of the initial catalytic activity even after the fourth run of hydrolysis. The lifetime of Ru(0)@MWCNTs was measured as 26400 turnovers over 29 h in the hydrolysis of AB at 25.0 ± 0.1 °C before deactivation. The work reported here also includes the kinetic studies depending on the temperature to determine the activation energy of the reaction (E(a) = 33 ± 2 kJ/mol) and the effect of catalyst concentration on the rate of the catalytic hydrolysis of AB, respectively. PMID:23113804

  11. Adsorption of naphthenic acids on high surface area activated carbons.

    Iranmanesh, Sobhan; Harding, Thomas; Abedi, Jalal; Seyedeyn-Azad, Fakhry; Layzell, David B

    2014-01-01

    In oil sands mining extraction, water is an essential component; however, the processed water becomes contaminated through contact with the bitumen at high temperature, and a portion of it cannot be recycled and ends up in tailing ponds. The removal of naphthenic acids (NAs) from tailing pond water is crucial, as they are corrosive and toxic and provide a substrate for microbial activity that can give rise to methane, which is a potent greenhouse gas. In this study, the conversion of sawdust into an activated carbon (AC) that could be used to remove NAs from tailings water was studied. After producing biochar from sawdust by a slow-pyrolysis process, the biochar was physically activated using carbon dioxide (CO2) over a range of temperatures or prior to producing biochar, and the sawdust was chemically activated using phosphoric acid (H3PO4). The physically activated carbon had a lower surface area per gram than the chemically activated carbon. The physically produced ACs had a lower surface area per gram than chemically produced AC. In the adsorption tests with NAs, up to 35 mg of NAs was removed from the water per gram of AC. The chemically treated ACs showed better uptake, which can be attributed to its higher surface area and increased mesopore size when compared with the physically treated AC. Both the chemically produced and physically produced AC provided better uptake than the commercially AC. PMID:24766592

  12. Adsorption of phenol by activated carbon: Influence of activation methods and solution pH

    Cherry stone based activated carbon derived from a canning industry was evaluated for its ability to remove phenol from an aqueous solution in a batch process. A comparative adsorption on the uptake of phenol by using commercial activated carbon (Chemviron CPG-LF), and two non-functional commercial polymeric adsorbents (MN-200 and XAD-2) containing a styrene-divinylbenzene macroporous hyperreticulated network have been also examined. Equilibrium studies were conducted in 25 mg L-1 initial phenol concentrations, 6.5-9 solution pH and at temperature of 30 deg. C. The experimental data were analyzed by the Langmuir and Freundlich isotherm models. Besides, the cherry stone based activated carbons were carried out by using zinc chloride and KOH activation agents at different chemical ratios (activating agent/precursor), to develop carbons with well-developed porosity. The cherry stone activated carbon prepared using KOH as a chemical agent showed a high surface area. According to the results, activated carbons had excellent adsorptive characteristics in comparison with polymeric sorbents and commercial activated carbon for the phenol removal from the aqueous solutions.

  13. Adsorption of phenol by activated carbon: Influence of activation methods and solution pH

    Beker, Ulker, E-mail: ubeker@gmail.co [Yildiz Technical University, Chemical Engineering Department, Davutpasa Campus, 34210 Esenler, Istanbul (Turkey); Ganbold, Batchimeg [National University of Mongolia, Faculty of Organic Chemistry, Ikh Surguuliin Gudamj 1, P.O. Box 46a/523, 210646 Ulaanbaatar (Mongolia); Dertli, Halil [Istanbul Technical University, Chemical Engineering Department, Maslak, Istanbul (Turkey); Guelbayir, Dilek Duranoglu [Yildiz Technical University, Chemical Engineering Department, Davutpasa Campus, 34210 Esenler, Istanbul (Turkey)

    2010-02-15

    Cherry stone based activated carbon derived from a canning industry was evaluated for its ability to remove phenol from an aqueous solution in a batch process. A comparative adsorption on the uptake of phenol by using commercial activated carbon (Chemviron CPG-LF), and two non-functional commercial polymeric adsorbents (MN-200 and XAD-2) containing a styrene-divinylbenzene macroporous hyperreticulated network have been also examined. Equilibrium studies were conducted in 25 mg L{sup -1} initial phenol concentrations, 6.5-9 solution pH and at temperature of 30 deg. C. The experimental data were analyzed by the Langmuir and Freundlich isotherm models. Besides, the cherry stone based activated carbons were carried out by using zinc chloride and KOH activation agents at different chemical ratios (activating agent/precursor), to develop carbons with well-developed porosity. The cherry stone activated carbon prepared using KOH as a chemical agent showed a high surface area. According to the results, activated carbons had excellent adsorptive characteristics in comparison with polymeric sorbents and commercial activated carbon for the phenol removal from the aqueous solutions.

  14. Adsorption of Remazol Black B dye on Activated Carbon Felt

    Donnaperna Lucio; Duclaux Laurent; Gadiou Roger

    2008-01-01

    The adsorption of Remazol Black B (anionic dye) on a microporous activated carbon felt is investigated from its aqueous solution. The surface chemistry of activated carbon is studied using X-ray microanalysis, "Boehm" titrations and pH of PZC measurements which indicates that the surface oxygenated groups are mainly acidic in nature. The kinetics of Remazol Black B adsorption is observed to be pH dependent and governed by the diffusion of the dye molecules. The experimental data can be explai...

  15. Scale-up activation of carbon fibres for hydrogen storage

    Kunowsky, Mirko; Marco Lozar, Juan Pablo; Cazorla Amorós, Diego; Linares Solano, Ángel

    2009-01-01

    In a previous study, we investigated, at a laboratory scale, the chemical activation of two different carbon fibres (CF), their porosity characterization, and their optimization for hydrogen storage [1]. In the present work, this study is extended to: (i) a larger range of KOH activated carbon fibres, (ii) a larger range of hydrogen adsorption measurements at different temperatures and pressures (i.e. at room temperature, up to 20 MPa, and at 77 K, up to 4 MPa), and (iii) a scaling-up activat...

  16. ACTIVATED CARBONS FROM VEGETAL RAW MATERIALS TO SOLVE ENVIRONMENTAL PROBLEMS

    Viktor Mukhin

    2014-06-01

    Full Text Available Technologies for active carbons obtaining from vegetable byproducts such as straw, nut shells, fruit stones, sawdust, hydrolysis products of corn cobs and sunflower husks have been developed. The physico-chemical characteristics, structural parameters and sorption characteristics of obtained active carbons were determined. The ability of carbonaceous adsorbents for detoxification of soil against pesticides, purification of surface waters and for removal of organic pollutants from wastewaters has been evaluated. The obtained results reveal the effectiveness of their use in a number of environmental technologies.

  17. Application of a Fused Carbon Nanomaterial Filter for Lunar Dust Abatement Project

    National Aeronautics and Space Administration — Seldon Laboratories, LLC, will apply its patented carbon nanotube filtration technology for air and nanoscale particulate engine exhaust filtration to NASA's Lunar...

  18. Pore structure of the activated coconut shell charcoal carbon

    Budi, E.; Nasbey, H.; Yuniarti, B. D. P.; Nurmayatri, Y.; Fahdiana, J.; Budi, A. S.

    2014-09-01

    The development of activated carbon from coconut shell charcoal has been investigated by using physical method to determine the influence of activation parameters in term of temperature, argon gas pressure and time period on the pore structure of the activated carbon. The coconut shell charcoal was produced by pyrolisis process at temperature of about 75 - 150 °C for 6 hours. The charcoal was activated at various temperature (532, 700 and 868 °C), argon gas pressure (6.59, 15 and 23.4 kgf/cm2) and time period of (10, 60 and 120 minutes). The results showed that the pores size were reduced and distributed uniformly as the activation parameters are increased.

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

    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

  20. An optimization study on removal of Zn from aqueous solution by ultrasound assisted preparation of activated carbon from alkaline impregnated hazelnut shell

    Nowadays, ultrasound has gained importance in a wide variety of industrial fields especially in wastewater and sewage treatment. Ultrasound exhibits several beneficial effects in solid liquid systems by means of the cavitations phenomenon by causing the formation of many microcracks on the solid surface; thus, it increases the surface area between the reactants and cleans solid reactant or catalyst particle surfaces. In this study, activated carbon adsorbent for removing heavy metal cations such as Zn2+ from aqueous solutions has been prepared. For this purpose, KOH solution was impregnated into hazelnut shells under ultrasonic irradiation. After filtration, hazelnut shells have been carbonized under inert N2 atmosphere. The experiments were planned by statistical design methods. Finally, activated carbons were characterized by the evolution of their zinc adsorption capacity. Optimum preparation conditions were obtained by using constrained optimization program by means of the Matlab computer software. Activated carbon with the maximum adsorption capacity was further characterized by using scanning electron microscopy. The alkaline impregnation into hazelnut shells under ultrasonic irradiation was found to be beneficial for preparation of activated carbon for use as adsorbents to remove Zn2+ from aqueous solutions. (author)

  1. Liquid-phase adsorption of phenol onto activated carbons prepared with different activation levels

    Hsieh, C.T.; Teng, H.S.

    2000-07-01

    The paper investigates the influence of the pore size distribution of activated carbon on the adsorption of phenol from aqueous solutions. Activated carbons with different porous structures were prepared by gasifying a bituminous coal char to different extents of burn-off. The results of adsorption experiments show that the phenol capacity of these carbons does not proportionally increase with their BET surface area. This reflects the heterogeneity of the carbon surface for adsorption. The pore size distributions of these carbons were found to vary with the burn-off level. The paper demonstrates that the heterogeneity of carbon surface for the phenol adsorption can be attributed to the different energies required for adsorption in different-size micropores.

  2. Demonstration of creep during filtration

    Christensen, Morten Lykkegaard; Bugge, Thomas Vistisen; Kirchheiner, Anders Løvenbalk; Keiding, Kristian

    The classical filtration theory assumes a unique relationship between the local filter cake porosity and the local effective pressure. For a number of compressible materials, it has however been observed that during the consolidation stage this may not be the case. It has been found that the...... production of filtrate also depends on the characteristic time for the filter cake solids to deform. This is formulated in the Terzaghi-Voigt model in which a secondary consolidation is introduced. The secondary consolidation may be visualized by plots of the relative cake deformation (U) v.s. the square...... magnitude as the primary consolidation (defined by the hydraulic retardation), the creep phenomenon may occur during filtration. This will lead to Ruth's plots characterized by a concave with two (more or less) distinct slopes. The slopes are defined by the relationship between the porosity and the...

  3. Production Scale-Up or Activated Carbons for Ultracapacitors

    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.

  4. Modeling Water Filtration

    Parks, Melissa

    2014-01-01

    Model-eliciting activities (MEAs) are not new to those in engineering or mathematics, but they were new to Melissa Parks. Model-eliciting activities are simulated real-world problems that integrate engineering, mathematical, and scientific thinking as students find solutions for specific scenarios. During this process, students generate solutions…

  5. Characteristics and properties of active carbon; El carbon activo sus caracteristicas y propiedades

    Groso Cruzado, G.; Brosa Echevarria, J.

    1998-12-01

    Active carbon (AC) is a solid possessing two properties which make it extremely useful in treating water. The first consists in trapping all kinds of organic contaminants in its walls so avidly that it can leave water practically free of such compounds. The second consists in destroying the free waste chlorine which has failed to react once it has completed its disinfecting action. As a result, virtually all industries requiring potable water employ active carbon as one of their basic treatment methods. (Author) 7 refs.

  6. Preparation and characterization of activated carbon from rubber-seed shell by physical activation with steam

    The use of rubber-seed shell as a raw material for the production of activated carbon with physical activation was investigated. The produced activated carbons were characterized by Nitrogen adsorption isotherms, Scanning electron microscope, Thermo-gravimetric and Differential scanning calorimetric in order to understand the rubber-seed shell activated carbon. The results showed that rubber-seed shell is a good precursor for activated carbon. The optimal activation condition is: temperature 880 oC, steam flow 6 kg h-1, residence time 60 min. Characteristics of activated carbon with a high yield (30.5%) are: specific surface area (SBET) 948 m2 g-1, total volume 0.988 m3 kg-1, iodine number of adsorbent (qiodine) 1.326 g g-1, amount of methylene blue adsorption of adsorbent (qmb) 265 mg g-1, hardness 94.7%. It is demonstrated that rubber-seed shell is an attractive source of raw material for producing high capacity activated carbon by physical activation with steam.

  7. Carbon Beam Radio-Therapy and Research Activities at HIMAC

    Radio-therapy with carbon ion beam has been carried out since 1994 at HIMAC (Heavy Ion Medical Accelerator in Chiba) in NIRS (National Institute of Radiological Sciences). Now, many types of tumors can be treated with carbon beam with excellent local controls of the tumors. Stimulated with good clinical results, requirement of the dedicated compact facility for carbon beam radio-therapy is increased. To realize this requirement, design study of the facility and the R and D's of the key components in this design are promoted by NIRS. According successful results of these activities, the dedicated compact facility will be realized in Gunma University. In this facility, the established irradiation method is expected to use, which is passive irradiation method with wobbler magnets and ridge filter. In this presentation, above R and D's will be presented together with clinical results and basic research activities at HIMAC

  8. Removal of micropollutants in municipal wastewater treatment plants by powder-activated carbon.

    Boehler, M; Zwickenpflug, B; Hollender, J; Ternes, T; Joss, A; Siegrist, H

    2012-01-01

    Micropollutants (MP) are only partly removed from municipal wastewater by nutrient removal plants and are seen increasingly as a threat to aquatic ecosystems and to the safety of drinking water resources. The addition of powder activated carbon (PAC) is a promising technology to complement municipal nutrient removal plants in order to achieve a significant reduction of MPs and ecotoxicity in receiving waters. This paper presents the salient outcomes of pilot- and full-scale applications of PAC addition in different flow schemes for micropollutant removal in municipal wastewater treatment plants (WWTPs). The sorption efficiency of PAC is reduced with increasing dissolved organic carbon (DOC). Adequate treatment of secondary effluent with 5-10 g DOC m(-3) requires 10-20 g PAC m(-3) of effluent. Counter-current use of PAC by recycling waste PAC from post-treatment in a contact tank with an additional clarifier to the biology tank improved the overall MP removal by 10 to 50% compared with effluent PAC application alone. A dosage of 15 g PAC m(-3) to a full-scale flocculation sand filtration system and recycling the backwash water to the biology tank showed similar MP elimination. Due to an adequate mixing regime and the addition of adapted flocculants, a good retention of the fine fraction of the PAC in the deep-bed filter were observed (1-3 g TSS m(-3); TSS: total suspended solids). With double use of PAC, only half of the PAC was required to reach MP removal efficiencies similar to the direct single dosage of PAC to the biology tank. Overall, the application of PAC in WWTPs seems to be an adequate and feasible technology for efficient MP elimination (>80%) from wastewater comparable with post ozonation. PMID:22949241

  9. Integrated pore blockage-cake filtration model for crossflow filtration

    Crossflow filtration is to be a key process in the treatment and disposal of approximately 60,000 metric tons of high-level radioactive waste stored at the Hanford Site in Richland, Washington. Pacific Northwest National Laboratory is assessing filter performance with waste simulant materials that mimic the chemical and physical properties of Hanford tank waste. Prior simulant studies indicated that waste filtration performance may be limited by pore and cake fouling. To limit the shutdown of waste treatment operations, the pre-treatment facility plans to recover filter flux losses from cake formation and filter fouling by frequently backpulsing the filter elements. The objective of the current paper is to develop a simple model of flux decline resulting from cake and pore fouling and potential flux recovery through backpulsing of the filters for Hanford waste filtration operations. To this end, a model capable of characterizing the decline in waste-simulant filter flux as a function of both irreversible pore blockage and reversible cake formation is proposed. This model is used to characterize the filtration behavior of Hanford waste simulants in both continuous and backpulsed operations. The model is then used to infer the optimal backpulse frequency under specific operating conditions.

  10. Highly active catalyst for vinyl acetate synthesis by modified activated carbon

    Chun Yan Hou; Liang Rong Feng; Fa Li Qiu

    2009-01-01

    A new zinc acetate catalyst which was prepared from modified activated carbon exhibited extreme activity towards the synthesis of vinyl acetate. The activated carbon was modified by nitric acid, vitriol and peroxyacetic acid (PAA). The effect on specific area, structure, pH and surface acidity groups of carriers by modification was discussed. Amount of carbonyl and carboxyl groups in activated carbon was increased by peroxyacetic acid treatment. The productivity of the new catalyst was 14.58% higher than that of catalyst prepared using untreated activated carbon. The relationship between amount of carbonyl and carboxyl groups (m) and catalyst productivity (P) was P = 1.83 + 2.26 x 10-3e3.17m. Reaction mechanism was proposed.

  11. Integrating carbon nanotube into activated carbon matrix for improving the performance of supercapacitor

    Highlights: ► Hydrothermal carbonization method to prepare “tube-in-activated carbon” composite. ► Due to high specific surface area, suitable pore size and low electrical resistance. ► It exhibited high capacitance value and excellent cyclibility for supercapacitor. - Abstract: A method of in situ integrating carbon nanotubes (CNTs) into activated carbon (AC) matrix was developed to improve the performance of AC as a supercapacitor electrode. Glucose solution containing pre-dispersed CNTs was hydrothermally carbonized to be a char-like intermediate product, and finally converted into a “tube-in-AC” structure by the chemical activation using KOH. The “tube-in-AC” composite had oxygen content of 12.98 wt%, specific surface area of 1626 m2/g and 90% of 1–2 nm micropores. It exhibited capacitance of 378 F/g in the aqueous KOH electrolyte and excellent cyclibility under high current, that is, the capacitance only decreased 4.6% after 2000 cycles at scanning rate of 100 mV/s. These performances of “tube-in-AC” electrode are better than those of commercial AC electrodes, post-mixed with CNTs or carbon black.

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

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

    2015-01-21

    Research activity toward the development of new sorbents for carbon dioxide (CO2) capture have been increasing quickly. Despite the variety of existing materials with high surface areas and high CO2 uptake performances, the cost of the materials remains a dominant factor in slowing their industrial applications. Here we report preparation and CO2 uptake performance of microporous carbon materials synthesized from asphalt, a very inexpensive carbon source. Carbonization of asphalt with potassium hydroxide (KOH) at high temperatures (>600 °C) yields porous carbon materials (A-PC) with high surface areas of up to 2780 m(2) g(-1) and high CO2 uptake performance of 21 mmol g(-1) or 93 wt % at 30 bar and 25 °C. Furthermore, nitrogen doping and reduction with hydrogen yields active N-doped materials (A-NPC and A-rNPC) containing up to 9.3% nitrogen, making them nucleophilic porous carbons with further increase in the Brunauer-Emmett-Teller (BET) surface areas up to 2860 m(2) g(-1) for A-NPC and CO2 uptake to 26 mmol g(-1) or 114 wt % at 30 bar and 25 °C for A-rNPC. This is the highest reported CO2 uptake among the family of the activated porous carbonaceous materials. Thus, the porous carbon materials from asphalt have excellent properties for reversibly capturing CO2 at the well-head during the extraction of natural gas, a naturally occurring high pressure source of CO2. Through a pressure swing sorption process, when the asphalt-derived material is returned to 1 bar, the CO2 is released, thereby rendering a reversible capture medium that is highly efficient yet very inexpensive. PMID:25531980

  13. The comparison of two activation techniques to prepare activated carbon from corn cob

    We report on the preparation of biomass-based activated carbons by the steam physical activation and KOH chemical activation methods. In addition, we also investigate their adsorption performance. By adjusting the reaction parameters, different carbon materials are prepared from corn residues and characterized using instrumental analyses such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Brunauer–Emmett–Teller (BET). It is found that the synthesized activated carbons exhibit high surface area (1600 m2 g−1) and large pore volume (2.01 cm3 g−1). Furthermore, the high methylene blue and iodine adsorption value and a considerable CO2 uptake (exceeding 1.5 mmol g−1) are attained with the activated carbons, showing their potential usage for the CO2 adsorbent. -- Highlights: ► We research the reaction parameters effect of two different activation methods. ► The effect of reaction parameters and activation methods on carbon were observed. ► The adsorption capabilities are comparable with the commercial activated carbon

  14. Activation and micropore structure of carbon-fiber composites

    Jagtoyen, M.; Derbyshire, F.; Kimber, G. [Univ. of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

    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.

  15. Morphosynthesis of cubic silver cages on monolithic activated carbon.

    Wang, Fei; Zhao, Hong; Lai, Yijian; Liu, Siyu; Zhao, Binyuan; Ning, Yuesheng; Hu, Xiaobin

    2013-11-14

    Cubic silver cages were prepared on monolithic activated carbon (MAC) pre-absorbed with Cl(-), SO4(2-), or PO4(3-) anions. Silver insoluble salts served as templates for the morphosynthesis of silver cages. The silver ions were reduced by reductive functional groups on MAC micropores through a galvanic cell reaction mechanism. PMID:24080952

  16. Ecotoxicological effects of activated carbon addition to sediments.

    Jonker, M.T.O.; Suijkerbuijk, M.P.; Schmitt, H.; Sinnige, T.L.

    2009-01-01

    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 po

  17. Magnetically Responsive Activated Carbons for Bio - and Environmental Applications

    Šafařík, Ivo; Horská, Kateřina; Popisková, K.; Šafaříková, Miroslava

    2012-01-01

    Roč. 4, č. 3 (2012), s. 346-352. ISSN 2035-1755 R&D Projects: GA ČR(CZ) GAP503/11/2263; GA MŠk LH12190 Institutional support: RVO:67179843 Keywords : Activated Carbon * Magnetic Modification * Magnetic Separation Subject RIV: EH - Ecology, Behaviour

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

    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.

  19. The determination of chromium in water samples by neutron activation analysis after preconcentration on activated carbon

    A method is presented for the determination of chromium in sea- and fresh water. Chromium is concentrated on activated carbon from a neutral solution after a previous reduction of chromate with sodium sulfite at pH 1.5. The adsorption conditions, acidity, concentrations, amount of carbon, stirring-time, sample-volume, salinity, the influence of storage on the ratio of tervalent to hexavalent chromium, were investigated. The final determination of the total chromium content is performed by instrumental neutron-activation analysis. By preconcentration on activated carbon, a differentiation between tervalent and hexavalent chromium is possible. A separate determination of both species is not yet feasible due to the high carbon blank and to the necessity of measuring the adsorption percentage on carbon. The lower limit of determination, which depends on the value of the carbon blank, is 0.05 μg Cr/l with a precision of 20%. The determination is hampered by the considerable blank from the carbon. The use of activated carbon prepared from recrystallized sugar will probably improve the lower limit of determination and possibly allow the determination of chromate. (T.G.)

  20. Utilization of HTGR on active carbon recycling energy system

    A new energy transformation concept based on carbon recycling, called as active carbon recycling energy system, ACRES, was proposed for a zero carbon dioxide emission process. The ACRES is driven availably by carbon dioxide free primary energy. High temperature gas cooled reactor (HTGR) is a candidate of the energy sources for ACRES. A smart ironmaking system with ACRES (iACRES) is one of application examples. The contribution of HTGR on iACRES was discussed thermodynamically in this study. A carbon material is re-used cyclically as energy carrier media in ACRES. Carbon monoxide (CO) had higher energy densities than hydrogen and was compatible with conventional process. Thus, CO was suitable recycling media for ACRES. Efficient regeneration of CO was a key technology for ACRES. A combined system of hydrogen production by water electrolysis and CO2 hydrogen reduction was candidate. CO2 direct electrolysis was also one of the candidates. HTGR was appropriate heat source for both water and CO2 electrolysises, and CO2 hydrogen reduction. Thermodynamic energy balances were calculated for both systems with HTGR for an ironmaking system. The direct system showed relatively advantage to the combined system in the stand point of enthalpy efficiency and simplicity of the process. One or two plants of HTGR are corresponding with ACRES system for one unit of conventional blast furnace. The proposed ACRES system with HTGR was expected to form the basis of a new energy industrial process that had low CO2 emission

  1. Impact of Acidification on Pollutants Fate and Soil Filtration Function

    Jarmila Makovniková

    2014-12-01

    Full Text Available The objective of this paper was to investigate the effects of simulated acid load on the fate of inorganic pollutants (Cd, Pb, soil sorption potential, soil filtration func-tion. We made use of a short-term acidification pot experiment with grown plant of spring barley cultivated at 4 different soil types (Fluvisol, Cambisol, Stagnosol, Podzol. The potential of soil filtration was evaluated according to the Eq.: [Soil filtration function]=[Potential of soil sorbents]+[Potential of total content of inor-ganic pollutants]. Potential of soil sorbents (PSS is defined by qualitative (pH, or-ganic matter quality - A400/600 and quantitative factors (carbon content-Cox, humus layer thickness-H according to the Eq.:[PSS]=F(pH+F(A465/665+F(Cox*F(H. Acid load significantly influenced soil sorption potential and thus affected increase in Cd and Pb mobility what was reflected in their transfer into the plants. Results of soil filtration function showed significant change of filtration function in Cambisol.

  2. Carbon monoxide affects electrical and contractile activity of rat myocardium

    Porokhnya Maria V; Haertdinov Nail N; Abramochkin Denis V; Zefirov Andrew L; Sitdikova Gusel F

    2011-01-01

    Abstract Background Carbon monoxide (CO) is a toxic gas, which also acts in the organism as a neurotransmitter. It is generated as a by-product of heme breakdown catalyzed by heme oxygenase. We have investigated changes in electrical and contractile activity of isolated rat atrial and ventricular myocardium preparations under the influence of CO. Methods Standard microelectrode technique was used for intracellular registration of electrical activity in isolated preparations of atrial and vent...

  3. Characterization of Filtration Scale-Up Performance

    Daniel, Richard C.; Billing, Justin M.; Luna, Maria L.; Cantrell, Kirk J.; Peterson, Reid A.; Bonebrake, Michael L.; Shimskey, Rick W.; Jagoda, Lynette K.

    2009-03-09

    The scale-up performance of sintered stainless steel crossflow filter elements planned for use at the Pretreatment Engineering Platform (PEP) and at the Waste Treatment and Immobilization Plant (WTP) were characterized in partial fulfillment (see Table S.1) of the requirements of Test Plan TP RPP WTP 509. This test report details the results of experimental activities related only to filter scale-up characterization. These tests were performed under the Simulant Testing Program supporting Phase 1 of the demonstration of the pretreatment leaching processes at PEP. Pacific Northwest National Laboratory (PNNL) conducted the tests discussed herein for Bechtel National, Inc. (BNI) to address the data needs of Test Specification 24590-WTP-TSP-RT-07-004. Scale-up characterization tests employ high-level waste (HLW) simulants developed under the Test Plan TP-RPP-WTP-469. The experimental activities outlined in TP-RPP-WTP-509 examined specific processes from two broad areas of simulant behavior: 1) leaching performance of the boehmite simulant as a function of suspending phase chemistry and 2) filtration performance of the blended simulant with respect to filter scale-up and fouling. With regard to leaching behavior, the effect of anions on the kinetics of boehmite leaching was examined. Two experiments were conducted: 1) one examined the effect of the aluminate anion on the rate of boehmite dissolution and 2) another determined the effect of secondary anions typical of Hanford tank wastes on the rate of boehmite dissolution. Both experiments provide insight into how compositional variations in the suspending phase impact the effectiveness of the leaching processes. In addition, the aluminate anion studies provide information on the consequences of gibbsite in waste. The latter derives from the expected fast dissolution of gibbsite relative to boehmite. This test report concerns only results of the filtration performance with respect to scale-up. Test results for boehmite

  4. PERFORMANCE OF ACTIVATED SLUDGE-POWDERED ACTIVATED CARBON-WET AIR REGENERATION SYSTEMS

    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 ...

  5. Improved methane storage capacities by sorption on wet active carbons

    Perrin, A.; Celzard, A.; Marache, J.F.; Furdin, G. [Universite Henri Poincare, Nancy (France). Laboratoire de Chimie du Solide Mineral

    2004-07-01

    The possibility of storing large amounts of natural gas within wet active carbons is examined. The sorption isotherms of methane at 2{sup o}C and up to 8 MPa are built for four carbonaceous materials. Three of them originate from the same precursor (coconut shell), are physically activated at various burn-offs and are mainly microporous. The fourth material is a highly mesoporous chemically activated pinewood carbon. These adsorbents are wetted with a constant weight ratio water/carbon close to 1. The resulting isotherms all exhibit a marked step occurring near the expected formation pressure of methane hydrates, thus supporting their occurrence within the porous materials. The amount of gas stored at the highest pressures investigated then ranges from 6 to 17 mol/kg of wet adsorbent (i.e., corresponding to 10-36 mol/kg of dry carbon), depending on the material. The results are discussed on the basis of the known pore texture of each adsorbent, and stoichiometries of the formed hydrates are calculated. Considerations about adsorption/desorption kinetics and metastability are also developed. (author)

  6. Structural Characterization and Property Study on the Activated Alumina-activated Carbon Composite Material

    CHEN Yan-Qing; WU Ren-Ping; YE Xian-Feng

    2012-01-01

    AlCl3,NH3·H2O,HNO3 and activated carbon were used as raw materials to prepare one new type of activated alumina-activated carbon composite material.The influence of heat treatment conditions on the structure and property of this material was discussed;The microstructures of the composite material were characterized by XRD,SEM,BET techniques;and its formaldehyde adsorption characteristic was also tested.The results showed that the optimal heat treatment temperature of the activated alumina-activated carbon composite material was 450 ℃,iodine adsorption value was 441.40 mg/g,compressive strength was 44 N,specific surface area was 360.07 m2/g,average pore size was 2.91 nm,and pore volume was 0.26 m3/g.According to the BET pore size distribution diagram,the composite material has dual-pore size distribution structure,the micro-pore distributes in the range of 0.6-1.7 nm,and the meso-pore in the range of 3.0-8.0 nm.The formaldehyde adsorption effect of the activated alumina-activated carbon composite material was excellent,much better than that of the pure activated carbon or activated alumina,and its saturated adsorption capacity was 284.19 mg/g.

  7. Preparation and Characterization of Sisal Fiber-based Activated Carbon by Chemical Activation with Zinc Chloride

    Sisal fiber, an agricultural resource abundantly available in China, has been used as raw material to prepare activated carbon with high surface area and huge pore volume by chemical activation with zinc chloride. The orthogonal test was designed to investigate the influence of zinc chloride concentration, impregnation ratio, activation temperature and activation time on preparation of activated carbon. Scanning electron micrograph, Thermo-gravimetric, N2-adsorption isotherm, mathematical models such as t-plot, H-K equation, D-R equation and BJH methods were used to characterize the properties of the prepared carbons and the activation mechanism was discussed. The results showed that ZnCl2 changed the pyrolysis process of sisal fiber. Characteristics of activated carbon are: BET surface area was 1628 m2/g, total pore volume was 1.316 m3/g and ratio of mesopore volume to total pore volume up to 94.3%. These results suggest that sisal fiber is an attractive source to prepare mesoporous high-capacity activated carbon by chemical activation with zinc chloride

  8. Noble gas control room accident filtration system for severe accident conditions (N-CRAFT)

    Severe accidents might cause the release of airborne radioactive substances to the environment of the NPP either due to containment leakages or due to intentional filtered containment venting. In the latter case aerosols and iodine are retained, however noble gases are not retainable by the FCVS or by conventional air filtration systems like HEPA filters and iodine absorbers. Radioactive noble gases nevertheless dominate the activity release depending on the venting procedure and the weather conditions. To prevent unacceptable contamination of the control room atmosphere by noble gases, AREVA GmbH has developed a noble gas control room accident filtration system (CRAFT) which can supply purified fresh air to the control room without time limitation. The retention process is based on dynamic adsorption of noble gases on activated carbon. The system consists of delay lines (carbon columns) which are operated by a continuous and simultaneous adsorption and desorption process. CRAFT allows minimization of the dose rate inside the control room and ensures low radiation exposure to the staff by maintaining the control room environment suitable for prolonged occupancy throughout the duration of the accident. CRAFT consists of a proven modular design either transportable or permanently installed. (author)

  9. Ligninolytic Activity of Ganoderma strains on Different Carbon Sources

    TYPUK ARTININGSIH

    2006-10-01

    Full Text Available Lignin is a phenylpropanoid polymers with only few carbon bonds might be hydrolized. Due to its complexity, lignin is particularly difficult to decompose. Ganoderma is one of white rot fungi capable of lignin degradation. The ligninolytic of several species Ganoderma growing under different carbon sources was studied under controlled conditions which P. chrysosporium was used as standard comparison.Three types of ligninolytic, namely LiP, MnP, and laccase were assessed quantitatively and qualitatively. Ratio between clear zone and diameter of fungal colony was used for measuring specific activity qualitatively.Four sspecies of Ganoderma showed positive ligninolytic qualitatively that G. lucidum KT2-32 gave the highest ligninolytic. Activity of LiP and MnP in different carbon sources was consistently resulted by G. lucidum KT2-32, while the highest activity of laccase was shown by G. ochrolaccatum SA2-14. Medium of Indulin AT affected production of protein extracellular and induced ligninolytic. Glucose, BMC, and pine sawdust did not affect the activity of ligninolytic. The specific activity of Ganoderma species was found to be higher than the one of P. chrysosporium.

  10. 77 FR 26496 - Certain Activated Carbon From the People's Republic of China: Preliminary Results of the Fourth...

    2012-05-04

    ... at Less Than Fair Value: Certain Activated Carbon From the People's Republic of China, 72 FR 15099... activated carbon is a powdered, granular, or pelletized carbon product obtained by ``activating'' with heat... activated carbon, including powdered activated carbon (``PAC''), granular activated......

  11. Preparation of activated carbons from olive-tree wood revisited. II. Physical activation with air

    Ould-Idriss, A.; Cuerda-Correa, E.M.; Fernandez-Gonzalez, C.; Alexandre-Franco, M.F.; Gomez-Serrano, V. [Extremadura Univ., Badajoz (Spain). Dept. of Organic and Inorganic Chemistry; Stitou, M. [Univ. Abdelmalek Esaadi, Tetouan (Morocco). Dept. de Chimie; Macias-Garcia, A. [Extremadura Univ., Badajoz (Spain). Dept. of Mechanical, Energetic and Materials Engineering

    2011-02-15

    Olive-tree has been grown in the Mediterranean countries for centuries. For an adequate development of the tree it must be subjected to different treatments such as trimming, large amounts of a woody residue being produced. Such a residue has been traditionally used as a domestic fuel or simply burnt in the landfield. In both cases greenhouse gases are generated to a large extent. Thus, the preparation of activated carbons from olive-tree wood appears as an attractive alternative to valorize this by-product. Commonly, two activation strategies are used with such an aim, namely chemical and physical activation. In this study, the optimization of the physical activation method with air for the production of activated carbon has been analyzed. The results obtained clearly show that if the preparation conditions are adequately controlled, it is possible to prepare activated carbons showing tailored properties in terms of micro- or mesoporous texture and surface area. (author)

  12. Combination of powdered activated carbon and powdered zeolite for enhancing ammonium removal in micro-polluted raw water.

    Liao, Zhen-Liang; Chen, Hao; Zhu, Bai-Rong; Li, Huai-Zheng

    2015-09-01

    Even zeolite is promising in ammonia pollution disposing, its removal efficiency is frequently interfered by organics. As activated carbon has good removal efficiency on organic contaminants, combination of two adsorbents may allow their respective adsorption characteristics into full play. This paper provides a performance assessment of the combination for enhancing ammonium removal in micro-polluted raw water. Gel-filtration chromatography (GFC) was carried out to quantify the molecular weight (MW) range of organic contaminants that powdered activated carbon (PAC) and powdered zeolite (PZ) can remove. The polydispersity difference which also calculated from GFC may indicate the wider organic contaminants removal range of PAC and the relatively centralized removal range of PZ. The jar tests of combination dosing confirm a synergistic effect which promotes ammonium removing. Nevertheless, it also shows an antagonism hindering the due removal performance of the two adsorbents on CODMn, while it is not much evident on UV254. Furthermore, a comparison study with simulated coagulation-sedimentation process was conducted to evaluate the optimum dosing points (spatial and temporal) of PAC and PZ among follows: suction well, pipeline mixer, early and middle phase of flocculation. We suggest to dose both two adsorbents into the early phase of flocculation to maximize the versatile removal efficiency on turbidity, ammonium and organic contaminants. PMID:25929873

  13. Waste management activities and carbon emissions in Africa

    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.

  14. VPO catalysts synthesized on substrates with modified activated carbons

    VPO catalysts were prepared on oxidized and unoxidized activated carbons differing in initial porous structure. Carbons were oxidized under relatively soft (30% H2O2, 200 deg. C) and hard (50% H2O2, 350 deg. C) conditions. Carbon modification was carried out hydrothermally in a traditional autoclave (HTT) or a microwave reactor (MWT). The synthesis was also carried out under hydrothermal (HTS or MWS) conditions. V2O5 and NH4VO3 were used as precursors. The samples are characterized by diversified porous structure at SBET = 732-1617 m2/g and Vpor = 0.44-0.90 cm3/g, as well as various degree of VPO crystallinity. Possibility of preparation of the VPO catalysts under ecologically appropriate conditions, i.e. in aqueous solutions, was shown.

  15. Irreversible adsorption of phenolic compounds by activated carbons

    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

  16. Evidence for a nickel-containing carbon monoxide dehydrogenase in Methanobrevibacter arboriphilicus.

    Hammel, K E; Cornwell, K L; Diekert, G B; Thauer, R K

    1984-01-01

    In growing cultures of Methanobrevibacter arboriphilicus (Methanobrevibacter arboriphilus), the synthesis of active carbon monoxide dehydrogenase required nickel. The 21-fold-purified enzyme from 63Ni-labeled cells of M. arboriphilicus comigrated with 63Ni during gel filtration. These results provide evidence that the carbon monoxide dehydrogenase of methanogens is a nickel protein.

  17. Nomex-derived activated carbon fibers as electrode materials in carbon based supercapacitors

    Leitner, K.; Lerf, A.; Winter, M.; Besenhard, J. O.; Villar-Rodil, S.; Suárez-García, F.; Martínez-Alonso, A.; Tascón, J. M. D.

    Electrochemical characterization has been carried out for electrodes prepared of several activated carbon fiber samples derived from poly (m-phenylene isophthalamide) (Nomex) in an aqueous solution. Depending on the burn-off due to activation the BET surface area of the carbons was in the order of 1300-2800 m 2 g -1, providing an extensive network of micropores. Their capability as active material for supercapacitors was evaluated by using cyclic voltammetry and impedance spectroscopy. Values for the capacitance of 175 F g -1 in sulfuric acid were obtained. Further on, it was observed that the specific capacitance and the performance of the electrode increase significantly with increasing burn-off degree. We believe that this fact can be attributed to the increase of surface area and porosity with increasing burn-off.

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

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

    2015-05-15

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

  19. Filtration Understanding: FY10 Testing Results and Filtration Model Update

    Daniel, Richard C.; Billing, Justin M.; Burns, Carolyn A.; Peterson, Reid A.; Russell, Renee L.; Schonewill, Philip P.; Shimskey, Rick W.

    2011-04-04

    This document completes the requirements of Milestone 2-4, Final Report of FY10 Testing, discussed in the scope of work outlined in the EM31 task plan WP-2.3.6-2010-1. The focus of task WP 2.3.6 is to improve the U.S. Department of Energy’s (DOE’s) understanding of filtration operations for high-level waste (HLW) to improve filtration and cleaning efficiencies, thereby increasing process throughput and reducing the Na demand (through acid neutralization). Developing the cleaning/backpulsing requirements will produce much more efficient operations for both the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and the Savannah River Site (SRS), thereby significantly increasing throughput by limiting cleaning cycles. The scope of this work is to develop the understanding of filter fouling to allow developing this cleaning/backpulsing strategy.

  20. Filtrations of free groups as intersections

    Efrat, Ido

    2013-01-01

    For several natural filtrations of a free group S we express the n-th term of the filtration as the intersection of all kernels of homomorphisms from S to certain groups of upper-triangular unipotent matrices. This generalizes a classical result of Grun for the lower central filtration. In particular, we do this for the n-th term in the lower p-central filtration of S.

  1. Filtration Behaviour and Fouling Mechanisms of Polysaccharides

    Sondus Jamal; Sheng Chang; Hongde Zhou

    2014-01-01

    This study investigated filtration behaviors of polysaccharides solutions, both alone and in mixture with proteins, in the short-time constant flux filtration with the focus on factors affecting the transmembrane pressure (TMP) increase rate, the irreversible filtration resistance, and the membrane rejection behavior. The results showed that the TMP increase rates in the short-time constant flux filtration of alginate solutions were significantly affected by the calcium addition, alginate con...

  2. Reflection of processes of non-equilibrium two-phase filtration in oil-saturated hierarchical medium in data of active wave geophysical monitoring

    Hachay, Olga; Khachay, Andrey; Khachay, Oleg

    2016-04-01

    The processes of oil extraction from deposit are linked with the movement of multi-phase multi-component media, which are characterized by non-equilibrium and non-linear rheological features. The real behavior of layered systems is defined by the complexity of the rheology of moving fluids and the morphology structure of the porous medium, and also by the great variety of interactions between the fluid and the porous medium [Hasanov and Bulgakova, 2003]. It is necessary to take into account these features in order to informatively describe the filtration processes due to the non-linearity, non-equilibrium and heterogeneity that are features of real systems. In this way, new synergetic events can be revealed (namely, a loss of stability when oscillations occur, and the formation of ordered structures). This allows us to suggest new methods for the control and management of complicated natural systems that are constructed on account of these phenomena. Thus the layered system, from which it is necessary to extract the oil, is a complicated dynamical hierarchical system. A comparison is provided of non-equilibrium effects of the influence of independent hydrodynamic and electromagnetic induction on an oil layer and the medium which it surrounds. It is known that by drainage and steeping the hysteresis effect on curves of the relative phase permeability in dependence on the porous medium's water saturation in some cycles of influence (drainage-steep-drainage) is observed. Using the earlier developed 3D method of induction electromagnetic frequency geometric monitoring, we showed the possibility of defining the physical and structural features of a hierarchical oil layer structure and estimating the water saturation from crack inclusions. This effect allows managing the process of drainage and steeping the oil out of the layer by water displacement. An algorithm was constructed for 2D modeling of sound diffraction on a porous fluid-saturated intrusion of a hierarchical

  3. Emulsions for interfacial filtration.

    Grillet, Anne Mary; Bourdon, Christopher Jay; Souza, Caroline Ann; Welk, Margaret Ellen; Hartenberger, Joel David; Brooks, Carlton, F.

    2006-11-01

    We have investigated a novel emulsion interfacial filter that is applicable for a wide range of materials, from nano-particles to cells and bacteria. This technology uses the interface between the two immiscible phases as the active surface area for adsorption of targeted materials. We showed that emulsion interfaces can effectively collect and trap materials from aqueous solution. We tested two aqueous systems, a bovine serum albumin (BSA) solution and coal bed methane produced water (CBMPW). Using a pendant drop technique to monitor the interfacial tension, we demonstrated that materials in both samples were adsorbed to the liquid-liquid interface, and did not readily desorb. A prototype system was built to test the emulsion interfacial filter concept. For the BSA system, a protein assay showed a progressive decrease in the residual BSA concentration as the sample was processed. Based on the initial prototype operation, we propose an improved system design.

  4. Ni supported on activated carbon as catalyst for flue gas desulfurization

    2010-01-01

    A series of Ni supported on activated carbon are prepared by excessive impregnation and the desulfurization activity is investigated. It has been shown that the activated carbon-supported Ni is an efficient solid catalyst for flue gas desulfurization. The activated carbon treated by HNO3 exhibits high desulfurization activity, and different amounts of loaded-Ni on activated carbon significantly influence the desulfurization activity. The catalysts are studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results of XRD and XPS indicate that the activated carbon treated by HNO3 can increase oxygen-containing functional groups. Ni on activated carbon after calcination at 800 °C shows major Ni phase and minor NiO phase, and with increasing Ni content on activated carbon, Ni phase increases and affects the desulfurization activity of the catalyst, which proves that Ni is the main active phase.

  5. Kinetic and Equilibrium Studies for the Removal of Bromate by the Modified Activated Carbon

    Muqing Qiu; Shuiying Xiong

    2015-01-01

    Bromate which was formed bromide dissolved in water during the ozonation process, is carcinogenic and mutagenic to humans. To avoid bromate damage, many countries strictly control its concentration in drinking water. Activated carbon is an effective adsorbent material widely used in water treatment. In order to enhance the adsorption of bromate ion on activated carbon, the modified activated carbon was obtained from granular activated carbon by chemical activation using cationic surfactant as...

  6. Antibacterial activity of carbon-coated zinc oxide particles.

    Sawai, Jun; Yamamoto, Osamu; Ozkal, Burak; Nakagawa, Zenbe-E

    2007-03-01

    Particles of ZnO coated with carbon (ZnOCC) were prepared and evaluated for their antibacterial activity. ZnO powder and poly(vinyl alcohol) (PVA) (polymerization degree: 2,000-95,000) were mixed at a mass ratio (ZnO/PVA) of 1, and then heated at 500-650 degree C for 3 h under argon gas with a flow rate of 50ml/min. Carbon deposited on the ZnOCC surface was amorphous as revealed by X-ray diffraction studies. The ZnOCC particles maintained their shape in water, even under agitation. The antibacterial activity of ZnOCC powder against Staphylococcus aureus was evaluated quantitatively by measuring the change in the electrical conductivity of the growth medium caused by bacterial metabolism (conductimetric assay). The conductivity curves obtained were analyzed using the growth inhibition kinetic model proposed by Takahashi for calorimetric evaluation, allowing the estimation of the antibacterial efficacy and kinetic parameters of ZnOCC. In a previous study, when ZnO was immobilized on materials, such as activated carbon, the amount of ZnO immobilized was approximately 10-50%, and the antibacterial activity markedly decreased compared to that of the original ZnO. On the other hand, the ZnOCC particles prepared in this study contained approximately 95% ZnO and possessed antibacterial activity similar to that of pure ZnO. The carbon-coating treatment could maintain the antibacterial efficacy of the ZnO and may be useful in the develop-ment of multifunctional antimicrobial materials. PMID:17408004

  7. Modeling equilibrium adsorption of organic micropollutants onto activated carbon

    De Ridder, David J.

    2010-05-01

    Solute hydrophobicity, polarizability, aromaticity and the presence of H-bond donor/acceptor groups have been identified as important solute properties that affect the adsorption on activated carbon. However, the adsorption mechanisms related to these properties occur in parallel, and their respective dominance depends on the solute properties as well as carbon characteristics. In this paper, a model based on multivariate linear regression is described that was developed to predict equilibrium carbon loading on a specific activated carbon (F400) for solutes reflecting a wide range of solute properties. In order to improve prediction accuracy, groups (bins) of solutes with similar solute properties were defined and solute removals were predicted for each bin separately. With these individual linear models, coefficients of determination (R2) values ranging from 0.61 to 0.84 were obtained. With the mechanistic approach used in developing this predictive model, a strong relation with adsorption mechanisms is established, improving the interpretation and, ultimately, acceptance of the model. © 2010 Elsevier Ltd.

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

    Jagtoyen, M.; Derbyshire, F.; Kimber, G. [Univ. of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

    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.

  9. Production of activated carbon from cellulosic fibers for environment protection

    Activated carbon fibers (ACF) have received an increasing attention in recent years as an adsorbent for purifying polluted gaseous and aqueous streams. Their preparation, characterization and application have been reported in many studies [1], which show that the porosity of ACF is dependent on activation conditions, as temperature, time or gas. ACF provide adsorption rates 2 to 50 times higher than Granular Activated Carbon [2], because of their low diameter (∼10 m) providing a larger external surface area in contact with the fluid compared with that of granules. Furthermore, their potential for the removal of various pollutants from water was demonstrated towards micro-organics like phenols [3], pesticides or dyes [4]. Generally, fibrous activated carbons are produced from natural or synthetic precursors by carbonization at 600-1000 C followed by an activation step by CO2 oe steam at higher temperature [2]. Another way to produce the fibrous activated carbons is chemical activation with H3PO4, HNO3, KOH...[5]. Different types of synthetic or natural fibers have been used as precursors of fibrous activated carbons since 1970: polyacrylonitrile (PAN), polyphenol, rayon, cellulose phosphate, pitch, etc. Each of them has its own applications and limitations. The synthetic fibers being generally expensive, it would be interesting to find out low-cost precursors from local material resources. This work is a part of a research exchange program between the Vietnamese National Center of Natural Sciences and Technology (Vietnam) and the Ecole des Mines de Nantes (Gepea, France), with the aim to find some economical solutions for water treatment. Fibrous activated carbons are produced from natural cellulose fibers, namely jute and coconut fibers, which are abundant in Vietnam as well as in other tropical countries, have a low ash content and a low cost in comparison with synthetic fibers. Two methods are compared to produce activated carbons: 1) a physical activation with

  10. Activated carbon from leather shaving wastes and its application in removal of toxic materials.

    Kantarli, Ismail Cem; Yanik, Jale

    2010-07-15

    In this study, utilization of a solid waste as raw material for activated carbon production was investigated. For this purpose, activated carbons were produced from chromium and vegetable tanned leather shaving wastes by physical and chemical activation methods. A detailed analysis of the surface properties of the activated carbons including acidity, total surface area, extent of microporosity and mesoporosity was presented. The activated carbon produced from vegetable tanned leather shaving waste produced has a higher surface area and micropore volume than the activated carbon produced from chromium tanned leather shaving waste. The potential application of activated carbons obtained from vegetable tanned shavings as adsorbent for removal of water pollutants have been checked for phenol, methylene blue, and Cr(VI). Adsorption capacities of activated carbons were found to be comparable to that of activated carbons derived from biomass. PMID:20382474

  11. Synthesis of carbon nanofibers on impregnated powdered activated carbon as cheap substrate

    A.A. Mamun

    2016-07-01

    Full Text Available The catalysis and characterization of carbon nanofibers (CNFs composite are reported in this work. Carbon nanofibers were produced on oil palm shell powdered activated carbon (PAC, which was impregnated with nickel. Chemical Vapor Deposition (CVD of C2H2 was used in the presence of hydrogen at ∼650 °C. The flow rates of carbon source and hydrogen were fixed. The CNFs formed directly on the surface of the impregnated PAC. Variable weight percentages (1%, 3%, 5%, 7% and 9% of the catalyst salt (Ni+2 were used for the impregnation. However, the best catalysis was observed on the substrate with 3% Ni+2. The product displayed a relatively high surface area, essentially constituted by the external surface. New functional groups also appeared compared to those in the PAC. Field Emission Scanning Microscopy (FESEM, Transmission Electron Microscopy (TEM, Fourier Transform Infrared (FTIR, BET surface area analysis and energy dispersive X-ray (EDX were used for the characterization of the new carbon nano product, which was produced through a clean novel process.

  12. Carbon nanofibers grafted on activated carbon as an electrode in high-power supercapacitors.

    Gryglewicz, Grażyna; Śliwak, Agata; Béguin, François

    2013-08-01

    A hybrid electrode material for high-power supercapacitors was fabricated by grafting carbon nanofibers (CNFs) onto the surface of powdered activated carbon (AC) through catalytic chemical vapor deposition (CCVD). A uniform thin layer of disentangled CNFs with a herringbone structure was deposited on the carbon surface through the decomposition of propane at 450 °C over an AC-supported nickel catalyst. CNF coating was controlled by the reaction time and the nickel content. The superior CNF/AC composite displays excellent electrochemical performance in a 0.5 mol L(-1) solution of K2 SO4 due to its unique structure. At a high scan rate (100 mV s(-1) ) and current loading (20 A g(-1) ), the capacitance values were three- and fourfold higher than those for classical AC/carbon black composites. Owing to this feature, a high energy of 10 Wh kg(-1) was obtained over a wide power range in neutral medium at a voltage of 0.8 V. The significant enhancement of charge propagation is attributed to the presence of herringbone CNFs, which facilitate the diffusion of ions in the electrode and play the role of electronic bridges between AC particles. An in situ coating of AC with short CNFs (below 200 nm) is a very attractive method for producing the next generation of carbon composite materials with a high power performance in supercapacitors working in neutral medium. PMID:23794416

  13. Mixture Based Outlier Filtration

    P. Pecherková

    2006-01-01

    Full Text Available Success/failure of adaptive control algorithms – especially those designed using the Linear Quadratic Gaussian criterion – depends on the quality of the process data used for model identification. One of the most harmful types of process data corruptions are outliers, i.e. ‘wrong data’ lying far away from the range of real data. The presence of outliers in the data negatively affects an estimation of the dynamics of the system. This effect is magnified when the outliers are grouped into blocks. In this paper, we propose an algorithm for outlier detection and removal. It is based on modelling the corrupted data by a two-component probabilistic mixture. The first component of the mixture models uncorrupted process data, while the second models outliers. When the outlier component is detected to be active, a prediction from the uncorrupted data component is computed and used as a reconstruction of the observed data. The resulting reconstruction filter is compared to standard methods on simulated and real data. The filter exhibits excellent properties, especially in the case of blocks of outliers. 

  14. Preparation and performance of carbon aerogel and activated carbon aerogel as electrode materials

    Carbon aerogel (CA) was prepared by the polycondensation of resorcinol (R) and formaldehyde (F) and then activated by CO2 flow. XRD analysis indicates that in the process of activation, CO2 infiltrates into the network of CA and weakens the(002) and (100) peaks. SEM analysis shows that the CO2 activation does not destroy the framework of CA but adds a great number of nano miropores, and accordingly the specific surface area and micropore proportion of CA are greatly improved. Electrochemical characterization was performed using cyclic Jantammetry and chronopotentiometry in 1 mol/L KOH aqueous solution electrolyte. The CA electrode with and without activation has a stable electrochemistry performance and preferable reversibility. The specific capacitance of CA is 103 F/g before activation, and reaches 371 F/g after activation due to the increase in specific area. (authors)

  15. Elimination of Pb2+ by absorption using activated carbon

    The main objective of this project is to choose the best economical process to take away the aqueous Pb2+ cation environment such as industrial waste water. adsorption using activated carbon has been chosen for the research. This method resulted having high adsorption and also has been economical. First of all, it has been examined to find out if this method was good enough to remove Pb2+ properly or not. Then other factors such as adsorption time, temperature, P H and...had gone under consideration. The conclusion showed that this method could reduce more than ninety percent (90%) of Pb2+ by general activated carbon from solution in a reasonable time. The best condition of eliminate this heavy metal in a best manner is to bring the temperature down, because the adsorption is an exothermic reaction, and the best P H for this reaction is 7 (neutral)

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

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

    2007-06-01

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

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

    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. Oviposition Attractancy of Bacterial Culture Filtrates: response of Culex quinquefasciatus

    S Poonam

    2002-04-01

    Full Text Available Oviposition attractants could be used for monitoring as well as controlling mosquitoes by attracting them to lay eggs at chosen sites. In the present study, culture filtrates of seven bacterial species were tested for their attractancy against gravid females of Culex quinquefasciatus. When their oviposition active indices (OAI were studied, the culture filtrates of Bacillus cereus and Pseudomonas fluorescens exhibited oviposition attractancy (OAI = >0.3 at 100 ppm and the OAI were respectively 0.70 and 0.47. Culture filtrates of B. thuringiensis var. israelensis (wild type, B. t. var. israelensis (mutant and B. sphaericus showed attractancy at 2000 ppm with OAI of respectively 0.71, 0.59 and 0.68. However, the OAI of B. megaterium as well as Azospirillum brasilense was 0.13 (at 2000 ppm, which was less than 0.3 required to be considered them as attractants. When the oviposition attractancy of the bacterial culture filtrates were compared with that of a known oviposition attractant, p-cresol (at 10 ppm, the culture filtrates of B. t. var. israelensis (wild type and B. cereus were found to be more active than p-cresol, respectively with 64.2 and 54.3% oviposition.

  19. Factors governing the adsorption of ethanol on spherical activated carbons

    Romero Anaya, Aroldo José; Lillo Ródenas, María Ángeles; Linares Solano, Ángel

    2015-01-01

    Ethanol adsorption on different activated carbons (mostly spherical ones) was investigated covering the relative pressure range from 0.001 to 1. Oxygen surface contents of the ACs were modified by oxidation (in HNO3 solution or air) and/or by thermal treatment in N2. To differentiate the concomitant effects of porosity and oxygen surface chemistry on ethanol adsorption, different sets of samples were used to analyze different relative pressure ranges (below 1000 ppmv concentration and close t...

  20. Activated carbon is an electron-conducting amphoteric ion adsorbent

    Biesheuvel, P. M.

    2015-01-01

    Electrodes composed of activated carbon (AC) particles can desalinate water by ion electrosorption. To describe ion electrosorption mathematically, accurate models are required for the structure of the electrical double layers (EDLs) that form within electrically charged AC micropores. To account for salt adsorption also in uncharged ACs, an "attraction term" was introduced in modified Donnan models for the EDL structure in ACs. Here it will be shown how instead of using an attraction term, c...

  1. Phenol Removal from Contaminated Water by Various Active Carbons

    Matějková, Martina; Papežová, Barbora; Šolcová, Olga

    Prague: Orgit, 2014, s. 97. ISBN 978-80-02-02555-9. [International Congress of Chemical and Process Engineering /21./ - CHISA 2014 and Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction /17./ - PRES 2014. Prague (CZ), 23.08.2014-27.08.2014] Grant ostatní: RFCS(XE) RFCR-CT-2011-00002 Institutional support: RVO:67985858 Keywords : active carbons * contaminated water * experiments Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  2. Petroleum contaminated ground-water: Remediation using activated carbon.

    Ayotamuno, M. J.; Kogbara, R. B.; Ogaji, S. O. T.; Probert, S. D.

    2006-01-01

    Ground-water contamination resulting from the leakage of crude oil and refined petroleum products during extraction and processing operations is a serious and a growing environmental problem in Nigeria. Consequently, a study of the use of activated carbon (AC) in the clean up was undertaken with the aim of reducing the water contamination to a more acceptable level. In the experiments described, crude-oil contamination of ground water was simulated under laboratory conditions using ground-wat...

  3. 75 FR 26927 - Certain Activated Carbon From the People's Republic of China: Notice of Preliminary Results of...

    2010-05-13

    ...: Certain Activated Carbon From the People's Republic of China, 71 FR 59721 (October 11, 2006); unchanged in... merchandise subject to this order is certain activated carbon. Certain activated carbon is a powdered... powdered activated carbon (``PAC''), granular activated carbon (``GAC''), and pelletized......

  4. 77 FR 33420 - Certain Activated Carbon From the People's Republic of China: Final Results of Expedited Sunset...

    2012-06-06

    ... Order: Certain Activated Carbon From the People's Republic of China, 72 FR 20988 (April 27, 2007... certain activated carbon. Certain activated carbon is a powdered, granular, or pelletized carbon product... order covers all physical forms of certain activated carbon, including powdered activated......

  5. Mobile surface water filtration system

    Aashish Vatsyayan

    2012-09-01

    Full Text Available To design a mobile system for surface water filtrationMethodology: the filtration of surface impurities begins with their retraction to concentrated thickness using non ionising surfactants, then isolation using surface tension property and sedimentation of impurities in process chamber using electrocoagulation. Result:following studies done to determine the rate of spreading of crude oil on water a method for retraction of spread crude oil to concentrated volumes is developed involving addition of non -ionising surfactants in contrast to use of dispersants. Electrocoagulation process involves multiple processes taking place to lead to depositionof impurities such as oil, grease, metals. Studies of experiments conducted reveals parameters necessary for design of electrocoagulation process chamber though a holistic approach towards system designing is still required. Propeller theory is used in determining the required design of propeller and the desired thrust, the overall structure will finally contribute in deciding the choice of propeller.

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

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

    1994-12-01

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

  7. Activated carbon becomes active for oxygen reduction and hydrogen evolution reactions.

    Yan, Xuecheng; Jia, Yi; Odedairo, Taiwo; Zhao, Xiaojun; Jin, Zhao; Zhu, Zhonghua; Yao, Xiangdong

    2016-06-21

    We utilized a facile method for creating unique defects in the activated carbon (AC), which makes it highly active for the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). The ORR activity of the defective AC (D-AC) is comparable to the commercial Pt/C in alkaline medium, and the D-AC also exhibits excellent HER activity in acidic solution. PMID:27277286

  8. Immobilization biological activated carbon used in advanced drinking water treatment

    2006-01-01

    Bacteria separated from a mature filter bed of groundwater treatment plants were incubated in a culture media containing iron and manganese. A consortium of 5 strains of bacteria removing iron and manganese were obtained by repeated enrichment culturing. It was shown from the experiments of effect factors that ironmanganese removal bacteria in the culture media containing both Fe and Mn grew better than in that containing only Fe, however, they were unable to grow in the culture media containing only Mn. When comparing the bacteria biomass in the case ofρ (DO) =2.8 mg/L andρ (DO) =9.0 mg/L, no significant difference was found.The engineering bacteria removing the organic and the bacteria removing iron and manganese were simultaneously inoculated into activated carbon reactor to treat the effluent of distribution network. The experimental results showed that by using IBAC ( Immobilization Biological Activated Carbon) treatment, the removal efficiency of iron, manganese and permanganate index was more than 98% , 96% and 55% , respectively. After the influent with turbidity of 1.5 NTU, color of 25 degree and offensive odor was treated, the turbidity and color of effluence were less than 0.5 NTU and 15 degree, respectively, and it was odorless. It is determined that the cooperation function of engineering bacteria and activated carbon achieved advanced drinking water treatment.

  9. Activated carbon for mercury control: Implications for fly ash management

    Pflughoeft-Hassett, Debra F.; Hassett, David J.; Buckley, Tera D.; Heebink, Loreal V.; Pavlish, John H. [Energy and Environmental Research Center, 15 North 23rd Street, Stop 9018, Grand Forks, North Dakota 58202-9018 (United States)

    2009-11-15

    As more utilities begin to use activated carbon injection (ACI) for mercury control, the potential for the presence of elevated concentrations of mercury, other air toxic elements, and activated carbon to impact fly ash management needs to be evaluated. Several Energy and Environmental Research Center (EERC) projects have allowed the collection of comparative baseline fly ash samples and associated fly ash-activated carbon (AC) samples from full-scale demonstrations of ACI for mercury emission control. These samples were evaluated for mercury and air toxic element content and mobility and for performance criteria to facilitate a better understanding of the impact of these components to specific utilization applications, including use as a mineral admixture in concrete. These data are compared with published data from samples collected at similar large-scale mercury emission control tests. The data presented are in agreement with previous results from the EERC, the U.S. Environmental Protection Agency, and elsewhere that mercury associated with fly ash is stable and unlikely to be released under most management conditions. Additionally, this paper will discuss the potential for fly ash-AC samples to be used as a mineral admixture in concrete and other large-volume use applications. (author)

  10. Adsorption of dyes onto activated carbon prepared from olive stones

    Souad NAJAR-SOUISSI; Abdelmottaleb OUEDERNI; Abdelhamid RATEL

    2005-01-01

    Activated carbon was produced from olive stones(OSAC) by a physical process in two steps. The adsorption character of this activated carbon was tested on three colour dyes molecules in aqueous solution: Methylene blue(MB), Rhodamine B(RB) and Congo Red(CR). The adsorption equilibrium was studied through isotherms construction at 30℃, which were well described by Langmuir model.The adsorption capacity on the OSAC was estimated to be 303 mg/g, 217 mg/g and 167 mg/g respectively for MB, RB and CR. This activated carbon has a similar adsorption properties to that of commercial ones and show the same adsorption performances. The adsorption kinetics of the MB molecule in aqueous solution at different initial concentrations by OSAC was also studied. Kinetic experiments were well fitted by a simple intra-particle diffusion model. The measured kinetics constant was influenced by the initial concentration and we found the following correlation: Kid = 1.55 C00.51 .

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

    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. PMID:23243870

  12. Effects of different Helicobacter pylori culture filtrates on growth of gastric epithelial cells

    Yan-Guo Yan; Gang Zhao; Jin-Ping Ma; Shi-Rong Cai; Wen-Hua Zhan

    2008-01-01

    AIM: To study the effects of different Helicobacter pylori (H py/orl) culture filtrates on growth of gastric epithelial cells.METHODS: Broth culture filtrates of H pylori were prepared. Gastric epithelial cells were treated with the filtrates, and cell growth was determined by growth curve and flow cytometry. DNA damage of gastric epithelial cells was measured by single-cell microgel electrophoresis.RESULTS: Gastric epithelial cells proliferated actively when treated by CagA-gene-positive broth culture filtrates, and colony formation reached 40%. The number of cells in S phase increased compared to controls. Comet assay showed 41.2% comet cells in GES-1 cells treated with CagA-positive filtrates (P<0.05).CONCLUSION: CagA-positive filtrates enhance the changes in morphology and growth characteristics of human gastric epithelial tumor cells. DNA damage maybe one of the mechanisms involved in the growth changes.

  13. Centrifugal membrane filtration - Task 9

    The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., the developer of a centrifugal membrane filtration technology, to demonstrate applications for the SpinTek technology within the US Department of Energy (DOE) Environmental management (EM) Program. The technology uses supported microporous membranes rotating at high rpm, under pressure, to separate suspended and colloidal solids from liquid streams, yielding a solids-free permeate stream and a highly concentrated solids stream. This is a crosscutting technology that falls under the Efficient Separations and Processing Crosscutting Program, with potential application to tank wastes, contaminated groundwater, landfill leachate, and secondary liquid waste streams from other remediation processes, including decontamination and decommissioning systems. Membrane-screening tests were performed with the SpinTek STC-X4 static test cell filtration unit, using five ceramic membranes with different pore size and composition. Based on permeate flux, a 0.25-microm TiO2/Al2O3 membrane was selected for detailed performance evaluation using the SpinTek ST-IIL centrifugal membrane filtration unit with a surrogate tank waste solution. An extended test run of 100 hr performed on a surrogate tank waste solution showed some deterioration in filtration performance, based on flux, apparently due to the buildup of solids near the inner portion of the membrane where relative membrane velocities were low. Continued testing of the system will focus on modifications to the shear pattern across the entire membrane surface to affect improved long-term performance

  14. Foam coating of filtration media

    Johansson, Mirva

    2015-01-01

    The objective of this thesis was to find out if foam coating could be applied to non-woven filtration media. The goal was to increase collection efficiency without significantly decreasing air permeability. In the theoretical part, foams and their characteristics were the centre of attention. Coating in general and, of course, foam coating were also studied. The empirical part consisted of series of foaming experiments and pilot scale coating experiments. In the foaming experiments differ...

  15. Preparation of Activated Carbon from Waste Tires and its application in Gasoline Removal from Water

    Mohammad Ali Baghapour

    2014-03-01

    Conclusion: Produced activated carbon has desired surface area and adsorptive capacity for gasoline adsorption in aquatic environments and it seems preparation activated carbon from waste tiers is cheap, effective and environment friendly.

  16. The Hodge filtration and the contact-order filtration of derivations of Coxeter arrangements

    Terao, Hiroaki

    2002-01-01

    The Hodge filtration of the module of derivations on the orbit space of a finite real reflection group acting on an $\\ell$-dimensional Euclidean space was introduced and studied by K. Saito. The filtration is equivalent data to the flat structure or the Frobenius manifold structure. We will show that the Hodge filtration coincides with the filtration by the order of contacts to the reflecting hyperplanes. Moreover, a standard basis for the Hodge filtration is explicitly given.

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

    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

  18. Absorption and adsorption of methane and carbon dioxide in hard coal and active carbon

    Milewska-Duda, J.; Duda, J.; Nodzenski, A.; Lakatos, J. [Stanislaw Staszic University of Mining and Metallurgy, Krakow (Poland). Faculty of Fuels and Energy

    2000-07-01

    The paper shows what can be deduced on sorption mechanisms in hard coals and active carbon by using a theoretical model of sorption of small molecules in elastic submicroporous materials. This multiple sorption model (MSM) describes both adsorption and absorption phenomena. Basic assumptions and formulae of the MSM are presented. The computations were performed for isotherms of CO{sub 2} and CH{sub 4} at elevated pressures on three coal samples of different rank and on an active carbon. Nonideality of the sorbates is handled by an original state equation providing consistent information on fugacity and cohesion energy corresponding to a given molar volume of sorbate molecules in the sorption system. Surface structure of the studied coals and energetic parameters of the systems determined with MSM are compared to those obtained by using BET and Dubinin-Radushkievitch equations.

  19. Self Cleaning HEPA Filtration without Interrupting Process Flow

    The strategy of protecting the traditional glass fibre HEPA filtration train from it's blinding contamination and the recovery of dust by the means of self cleaning, pre-filtration is a proven means in the reduction of ultimate disposal volumes and has been used within the Fuel Production Industry. However, there is an increasing demand in nuclear applications requiring elevated operating temperatures, fire resistance, moisture resistance and chemical composition that the existing glass fibre HEPA filtration cannot accommodate, which can be remedied by the use of a metallic HEPA filter media. Previous research (Bergman et al 1997, Moore et al 1992) suggests that the then costs to the DOE, based on a five year life cycle, was $29.5 million for the installation, testing, removal and disposal of glass fibre HEPA filtration trains. Within these costs, $300 was the value given to the filter and $4,450 was given to the peripheral activity. Development of a low cost, cleanable, metallic, direct replacement of the traditional filter train will the clear solution. The Bergman et al work has suggested that a 1000 ft3/min, cleanable, stainless HEPA could be commercially available for $5,000 each, whereas the industry has determined that the truer cost of such an item in isolation would be closer to $15,000. This results in a conflict within the requirement between 'low cost' and 'stainless HEPA'. By proposing a system that combines metallic HEPA filtration with the ability to self clean without interrupting the process flow, the need for a tradition HEPA filtration train will be eliminated and this dramatically reduces the resources required for cleaning or disposal, thus presenting a route to reducing ultimate costs. The paper will examine the performance characteristics, filtration efficiency, flow verses differential pressure and cleanability of a self cleaning HEPA grade sintered metal filter element, together with data to prove the contention. (authors)

  20. Enhanced photocatalytic activity of titanium dioxide by nut shell carbon

    Shi Xiaoliang, E-mail: sxl@whut.edu.cn [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Wang Sheng; Dong Xuebin [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Zhang Qiaoxin [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China)

    2009-08-15

    Nut shell carbon (NSC)-nanotitanium dioxide (TiO{sub 2}) composites were prepared by sol-gel method. Photocatalytic activity on degradation of dye Rhodamine B was studied. X-ray diffraction, field emission scanning electron microscopy, Brunauer-Emmett-Teller surface area, pore size distribution, ultraviolet-vis light absorption spectrum, and photoluminescence spectrum were carried out to characterize the composite catalyst. The results indicated that the photocatalytic activity of NSC-nano-TiO{sub 2} composites was much higher than P25 (Degussa). NSC could greatly absorb the organic substance and oxygen of solution because of its large surface area.

  1. Water Hyacinths and Alligator Weeds for Final Filtration of Sewage

    Wolverton, B. C.; Mcdonald, R. C.; Gordon, J.

    1976-01-01

    The potential of water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxerides) (Mart.) Griesb. as secondary and tertiary filtration systems for domestic sewage was demonstrated. These two vascular aquatic plants reduced the suspended solids, total Kjeldahl nitrogen, total phosphorus, BOD sub 5, and total organic carbon levels in domestic sewage from 60 percent to 98 percent within a two week period. These plants grown in domestic sewage were also free of toxic levels of trace heavy metals.

  2. Impacts of ozonation on the competition between organic micro-pollutants and effluent organic matter in powdered activated carbon adsorption.

    Zietzschmann, F; Mitchell, R-L; Jekel, M

    2015-11-01

    This study investigates if ozonation of wastewater treatment plant (WWTP) effluent can reduce the negative impacts of effluent organic matter (EfOM) on the adsorption of organic micro-pollutants (OMP) onto powdered activated carbon (PAC). Pre-treatment of the water included membrane filtration for the removal of suspended/colloidal organics, ozonation with various specific ozone consumptions, and subsequent OMP spiking to comparable initial concentrations in all of the ozonated waters. This approach allowed for comparative PAC adsorption tests. Adsorption analyses show that the adsorbability of EfOM decreases with increasing specific ozone consumptions. This is also reflected by liquid chromatography with online carbon and UV254 detection (LC-OCD) which shows the ozone-induced disintegration of large EfOM into smaller fragments. Also, small organic neutrals are decreased while the small organic acids peak continuously increases with rising specific ozone consumptions. UV254 demonstrates that the aromaticity of all LC-OCD fractions continuously declines together with increasing specific O3 consumptions. This explains the varying EfOM adsorbabilities that occur due to ozonation. The ozone-induced decrease of EfOM adsorbability directly translates into reduced adsorption competition against the adsorption of OMP. With higher specific ozone consumptions, OMP removal and OMP loadings increase. The reduced adsorption competition is reflected in the outputs from equivalent background compound (EBC) modeling. In each of the ozonated waters, correlations between the OMP removals and the UV254 removal were found. PMID:26231581

  3. Converting poultry litter to activated carbon: optimal carbonization conditions and product sorption for benzene.

    Guo, Mingxin; Song, Weiping

    2011-12-01

    To promote utilization of poultry litter as a source material for manufacturing low-cost activated carbon (AC) that can be used in wastewater treatment, this study investigated optimal production conditions and water-borne organic sorption potential of poultry litter-based AC. Pelletized broiler litter was carbonized at different temperatures for varied time periods and activated with steam at a range of flow rate and time. The AC products were examined for quality characteristics using standard methods and for organic sorption potentials using batch benzene sorption techniques. The study shows that the yield and quality of litter AC varied with production conditions. The optimal production conditions for poultry litter-based AC were carbonization at 700 degrees C for 45 min followed by activation with 2.5 ml min(-1) steam for another 45 min. The resulting AC possessed an iodine number of 454 mg g(-1) and a specific surface area of 403 m2 g(-1). It sorbed benzene in water following sigmoidal kinetic and isothermal patterns. The sorption capacity for benzene was 23.70 mg g(-1), lower than that of top-class commercial AC. The results, together with other reported research findings, suggest that poultry litter is a reasonable feedstock for low-cost AC applicable to pre-treat wastewater contaminated by organic pollutants and heavy metals. PMID:22439566

  4. Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

    Catalysis and regeneration efficiency of granular activated carbon (GAC) and activated carbon fiber (ACF) were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange (MO) by the combined treatment can increase 22% (for GAC) and 24% (for ACF) respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H2O2 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.

  5. Carbonic anhydrase activity in isolated chloroplasts of chlamydomonas reinhardtii

    In a new assay of carbonic anhydrase, NaH14CO3 solution at the bottom of a sealed vessel releases 14CO3 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 ± 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 ± 1.9 and 2.8 ± 7.8 WAU/mg chl respectively. Chloroplasts isolated from CWD and CIA-3/CW15 and subsequently disrupted gave 64.0 ± 14.7 and 2.8 ± 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

  6. Carbon monoxide affects electrical and contractile activity of rat myocardium

    Porokhnya Maria V

    2011-06-01

    Full Text Available Abstract Background Carbon monoxide (CO is a toxic gas, which also acts in the organism as a neurotransmitter. It is generated as a by-product of heme breakdown catalyzed by heme oxygenase. We have investigated changes in electrical and contractile activity of isolated rat atrial and ventricular myocardium preparations under the influence of CO. Methods Standard microelectrode technique was used for intracellular registration of electrical activity in isolated preparations of atrial and ventricular myocardium. Contractions of atrial myocardial stripes were registered via force transducer. Results CO (10-4 - 10-3 M caused prominent decrease of action potential duration (APD in working atrial myocardium as well as significant acceleration of sinus rhythm. In addition CO reduced force of contractions and other parameters of contractile activity. Inhibitor of heme oxygenase zinc protoporphyrin IX exerts opposite effects: prolongation of action potential, reduction of sinus rhythm rate and enhancement of contractile function. Therefore, endogenous CO, which may be generated in the heart due to the presence of active heme oxygenase, is likely to exert the same effects as exogenous CO applied to the perfusing medium. In ventricular myocardium preparations exogenous CO also induced shortening of action potential, while zinc protoporphyrin IX produced the opposite effect. Conclusions Thus, endogenous or exogenous carbon monoxide may act as an important regulator of electrical and contractile cardiac activity.

  7. Speculative and hedging activities in the European carbon market

    We explore the dynamics of the speculative and hedging activities in European futures carbon markets by using volume and open interest data. A comparison of the three phases in the European Union Emission Trading Scheme (EU ETS) reveals that (i) Phase II of the EU ETS seems to be the most speculative phase to date and (ii) the highest degree of speculative activity for every single phase occurs at the moment of listing the contracts for the first time. A seasonality analysis identifies a higher level of speculation in the first quarter of each year, related to the schedule of deadlines of the EU ETS. In addition, a time series analysis confirms that most of the speculative activity each year occurs in the front contract, whereas the hedging demand concentrates in the second-to-deliver futures contract. -- Highlights: •This study explores the evolution of speculative and hedging activities in futures carbon markets by using volume and open interest data. •Phase II of the EU ETS seems to be the most speculative phase to date. •A seasonality analysis identifies a higher level of speculation in the first quarter of each year. •Most of the speculative activity occurs in the front contract. •The hedging demand concentrates in the second-to-deliver futures contract

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

    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. PMID:24080293

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

    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.

  10. Adsorption of triton X100 and potassium hydrogen phthalate on granular activated carbon from date pits

    Merzougui, Z.; Nedjah, S.; Azoudj, Y.; Addoun, F. [Laboratoire d' etude physic-chimique des materiaux et application a l' environnement, Faculte de Chimie, USTHB (Algeria)], E-mail: zmerzougi@yahoo.fr

    2011-07-01

    Activated carbons, thanks to their versatility, are being used in the water treatment sector to absorb pollutants. Several factors influence the adsorption capacity of activated carbon and the aim of this study was to assess the effects of the porous texture and chemical nature of activated carbons on the adsorption of triton X100 and potassium hydrogen phthalate. Activated carbons used in this study were prepared from date pits with ZnCl2, KOH and H3PO4 by carbonization without adjuvant and adsorption of triton X100 and potassium hydrogen phthalate was conducted at 298K. Results showed that activated carbons prepared from date pits have a great potential for removing organic and inorganic pollutants from water and that the adsorption potential depends on the degree of activation of the activated carbons and on the compounds to absorb. This study highlighted that an increase of the carbon surface area and porosity results in a better adsorption capacity.

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

    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 (SBET) analysis and iodine number. The carbons, ZSLC-800 and ZHVC-800, showed surface area around 802 and 783 m2 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

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

    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. PMID:24845325

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

    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.

  14. Barrier properties of poly(vinyl alcohol) membranes containing carbon nanotubes or activated carbon.

    Surdo, Erin M; Khan, Iftheker A; Choudhury, Atif A; Saleh, Navid B; Arnold, William A

    2011-04-15

    Carbon nanotube addition has been shown to improve the mechanical properties of some polymers. Because of their unique adsorptive properties, carbon nanotubes may also improve the barrier performance of polymers used in contaminant containment. This study compares the barrier performance of poly(vinyl alcohol) (PVA) membranes containing single-walled carbon nanotubes (SWCNTs) to that for PVA containing powdered activated carbon (PAC). Raw and surface-functionalized versions of each sorbent were tested for their abilities to adsorb 1,2,4-trichlorobenzene and Cu(2+), representing the important hydrophobic organic and heavy metal contaminant classes, as they diffused across the PVA. In both cases, PAC (for 1,2,4-trichlorobenzene) and functionalized PAC (for Cu(2+)) outperformed SWCNTs on a per mass basis by trapping more of the contaminants within the barrier membrane. Kinetics of sorption are important in evaluating barrier properties, and poor performance of SWCNT-containing membranes as 1,2,4-TCB barriers is attributed to kinetic limitations. PMID:21349636

  15. Probing mechanics and activity of cytoskeletal networks using carbon nanotubes

    Fakhri, Nikta

    2013-03-01

    We use single-walled carbon nanotubes (SWNTs) as multi-scale micro-probes to monitor transport and fluctuations in cytoskeletal networks. SWNTs are nanometer-diameter hollow carbon filaments with micrometer lengths and a tunable bending stiffness. Their persistence length varies between 20-100 microns. We study the motion of individual SWNTs in reconstituted actin networks by near-infrared fluorescence microscopy. At long times, SWNTs reptate through the networks. At short times, SWNTs sample the spectrum of thermal fluctuations in the networks. We can calculate complex shear moduli from recorded fluctuations and observe power-law scaling in equilibrium actin networks. In the non-equilibrium cytoskeleton of cells we have targeted SWNTs to kinesin motors and thereby to their microtubule tracks. We observe both transport along the tracks as well as active fluctuations of the tracks themselves. Human Frontier Science Program Cross-Disciplinary Fellow

  16. Electric Double-layer Capacitor Based on Activated Carbon Material

    2000-01-01

    In this study electric double-layer capacitors (EDLCs) based on activated carbon material and organic electrolyte (tetraethyl ammonium tetrafluoroborate) were explored. The fabrication method for EDLC is presented and the performance of EDLC was examined by using the cyclic voltammetry, constant-current charging and discharging technique, electrochemical impedance spectroscopy measurements. Influence of various components and design parameters on the performance of the capacitors were preliminarily investigated. Up to now, EDLC based on carbon materials can deliver 20.7 W/kg at the discharge rate ofI=0.3 mA, together with the energy density of 8.5 Wh/kg. Equivalent series resistance (ESR) is 0.716 Ω.cm2. The specific power of the capacitor is low and further attempts to raise the power capability of the capacitors are necessary. Some considerations are put forward to further improve the performance of EDLC.

  17. Kinetic studies on carbon dioxide capture using lignocellulosic based activated carbon

    CO2 (Carbon dioxide) emissions are one of the greenhouse gases that cause global warming. The power generation industry is one of the main emitters of CO2, and the emissions are expected to increase in the coming years as there seems to be no abatement in the consumption of fossil fuels for the production of electricity. Thus, there is a need for CO2 adsorption technologies to mitigate the emissions. However, there are several disadvantages associated with the current adsorption technologies. One of the issues is corrosion and the need for specialized equipment. Therefore, alternative and more sustainable materials are sought after to improve the viability of the adsorption technology. In this study, several types of agricultural wastes were used as activated carbon precursors for CO2 adsorption process in a TGA (thermogravimetric analyser). The adsorption was also modelled through a pseudo-first order and second order model, Elovich's kinetic model, and an intra-particle diffusion model. From the correlation coefficient, it was found that pseudo-second order model was well-fitted with the kinetic data. In addition, activation energy below than 42 kJ/mol confirmed that the physisorption process occurred. - Highlights: • Utilization of lignocellulosic wastes for production of activated carbon. • Single CO2 activation that yields good adsorptive capacity of adsorbent. • Activation temperature has the most prominent effect on adsorptive properties. • CO2 adsorption capacity reduces with increasing of adsorption temperature. • Pseudo-second order kinetic model shows best fits to the experimental data

  18. EM Task 9 - Centrifugal Membrane Filtration

    This project is designed to establish the utility of a novel centrifugal membrane filtration technology for the remediation of liquid mixed waste streams at US Department of Energy (DOE) facilities in support of the DOE Environmental Management (EM) program. The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., a small business and owner of the novel centrifugal membrane filtration technology, to establish the applicability of the technology to DOE site remediation and the commercial viability of the technology for liquid mixed waste stream remediation. The technology is a uniquely configured process that makes use of ultrafiltration and centrifugal force to separate suspended and dissolved solids from liquid waste streams, producing a filtered water stream and a low-volume contaminated concentrate stream. This technology has the potential for effective and efficient waste volume minimization, the treatment of liquid tank wastes, the remediation of contaminated groundwater plumes, and the treatment of secondary liquid waste streams from other remediation processes, as well as the liquid waste stream generated during decontamination and decommissioning activities

  19. Simulations of Microbial-Enhanced Oil Recovery: Adsorption and Filtration

    Nielsen, Sidsel Marie; Nesterov, Igor; Shapiro, Alexander

    2014-01-01

    introduced to study the process efficiency: the dimensionless time at which average recovery between pure water injection and maximum surfactant effect is reached. This characteristic recovery period (CRP) was studied as a function of the different MEOR parameters such as bacterial activity, filtration......In the context of microbial-enhanced oil recovery (MEOR) with injection of surfactant-producing bacteria into the reservoir, different types of bacteria attachment and growth scenarios are studied using a 1D simulator. The irreversible bacteria attachment due to filtration similar to the deep bed...... applied to filtration model provides formation of two oil banks during recovery. This feature is not reproduced by application of REA model or DBF with growth in attached phase. This makes it possible to select a right model based on the qualitative analysis of the experimental data. A criterion is...

  20. Optimization and characterization of sliced activated carbon prepared from date palm tree fronds by physical activation

    Sliced activated carbons were prepared from palm tree fronds, a biomass material, using a single step physical method. Effect of the synthetic parameters on the surface area, pore size and pore volume of the activated carbon were studied, pursuing by the optimization of studied parameters. The activation temperature, heating ramp rate, reaction vessel pressure and the CO2 flowrate were found to be the influential parameters for the synthesis of sliced activated carbon with larger porosity and surface area. The optimum conditions to synthesize the porous activated carbon bearing high pore volume and surface area were studied and identified. Highest surface area of 1094 m2 g−1 was achieved under the optimum conditions. Scanning electron microscopy (SEM) for the porosity and Fourier transform infrared spectroscopy (FTIR) for surface functional groups and transmission electron microscopy (TEM) confirms the presence of uniform nanoparticles of 2.1385 nm. - Highlights: • Used local waste material from Saudi Arabia. • Convenient single step physical activation procedure. • Achievement of 1094 m2 g−1 Surface Area, particle size 2.1385 nm and 0.4382 cm3 g−1 Pore volume

  1. Preparation of mesoporous activated carbons from coal liquefaction residue for methane decomposition

    Jianbo Zhang; Lijun Jin; Shengwei Zhu; Haoquan Hu

    2012-01-01

    Mesoporous activated carbons were prepared from direct coal liquefaction residue (CLR) by KOH activation method,and the experiments were carried out to investigate the effects of KOH/CLR ratio,solvent for mixing the CLR and KOH,and carbonization procedure on the resultant carbon texture and catalytic activity for catalytic methane decomposition (CMD).The results showed that optimal KOH/CLR ratio of 2 ∶ 1;solvent with higher solubility to KOH or the CLR,and an appropriate carbonization procedure are conductive to improving the carbon pore structure and catalytic activity for CMD.The resultant mesoporous carbons show higher and more stable activity than microporous carbons.Additionally,the relationship between the carbon textural properties and the catalytic activity for CMD was also discussed.

  2. PREPARATION OF MICROWAVE ABSORBING NICKEL-BASED ACTIVATED CARBON BY ELECTROLESS PLATING WITH PALLADIUM-FREE ACTIVATION

    Boyang Jia; Lijuan Wang

    2010-01-01

    Nickel-based activated carbon was prepared from coconut shell activated carbon by electroless plating with palladium-free activation. The materials were characterized by scanning electron microscopy (SEM), X-ray energy dispersion spectroscopy (EDS), vibrating sample magnetometry (VSM), and vector network analyzer, respectively. The results show that the surface of the activated carbon was covered by a Ni-P coating, which was uniform, compact, and continuous and had an obvious metallic sheen. ...

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

    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. PMID:26686184

  4. Antimicrobial Activity of Chitosan-Carbon Nanotube Hydrogels

    Jayachandran Venkatesan

    2014-05-01

    Full Text Available In the present study, we have prepared chitosan-carbon nanotube (Chitosan-CNT hydrogels by the freeze-lyophilization method and examined their antimicrobial activity. Different concentrations of CNT were used in the preparation of Chitosan-CNT hydrogels. These differently concentrated CNT hydrogels were chemically characterized using Fourier Transform-Infrared Spectroscopy, Scanning Electron Microscopy and Optical microscopy. The porosity of the hydrogels were found to be >94%. Dispersion of chitosan was observed in the CNT matrix by normal photography and optical microscopy. The addition of CNT in the composite scaffold significantly reduced the water uptake ability. In order to evaluate antimicrobial activity, the serial dilution method was used towards Staphylococcus aureus, Escherichia coli and Candida tropicalis. The composite Chitosan-CNT hydrogel showed greater antimicrobial activity with increasing CNT concentration, suggesting that Chitosan-CNT hydrogel scaffold will be a promising biomaterial in biomedical applications.

  5. Electrochemical characteristics of activated carbon nanofiber electrodes for supercapacitors

    Seo, Min-Kang [Dept. of Chemistry, Inha University, 253, Nam-gu, Incheon 402-751 (Korea, Republic of); Park, Soo-Jin [Dept. of Chemistry, Inha University, 253, Nam-gu, Incheon 402-751 (Korea, Republic of)], E-mail: sjpark@inha.ac.kr

    2009-08-25

    In this work, poly(amide imide) solutions in dimethylformamide were electrospun into webs consisting of 350 nm ultrafine nanofibers. These nanofiber webs were used to produce activated carbon nanofibers (ACNFs), through stabilization and carbonisation-activation processes. Experimental results indicated that ACNFs activated at 800 deg. C afforded the highest specific surface area but low mesopore volume. The high specific surface area, mainly due to the micropores, introduced maximum specific capacitance at low current density (150 F g{sup -1} at 10 mA g{sup -1}). Elevating the volume fraction of mesopores gave maximum specific capacitance at high current density (100 F g{sup -1} at 1000 mA g{sup -1}), which could be explained on the basis of ion mobility in the pores. Thus, the capacitance of the supercapacitors was strongly dependent on the specific surface area and micro- or mesopore volume of the ACNFs.

  6. Coupling dehydrogenation of isobutane in the presence of carbon dioxide over chromium oxide supported on active carbon

    Jian Fei Ding; Zhang Feng Qin; Xue Kuan Li; Guo Fu Wang; Jian Guo Wang

    2008-01-01

    The dehydrogenation of isobutane (IB) to produce isobutene coupled with reverse water gas shift in the presence of carbon dioxide was investigated over the catalyst Cr2O3 supported on active carbon (Cr2O3/AC). The results illustrated that isobutane c onversion and isobutene yield can be enhanced through the reaction coupling in the presence of carbon dioxide. Moreover, carbon dioxide can partially eliminate carbonaceous deposition on the catalyst and keep the active phase (Cr2O3), which are then helpful to alleviate the catalyst deactivation.

  7. Activated carbon fibers prepared from quinoline and isoquinoline pitches

    Mochida, I.; An, K.; Korai, Y. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study; Kojima, T.; Komatsu, M. [Mitsubishi Gas Chemical Co. Inc., Tokyo (Japan); Yoshikawa, M. [Osaka Gas Co. Ltd., Osaka (Japan)

    1998-11-01

    Nitrogen enriched activated carbon fibers (ACFs) were prepared from isotropic quinoline and isoquinoline pitches produced by the catalytic action of HF/BF3 through spinning, stabilization, carbonization, and oxidative activation. The pitches exhibited excellent spinnability, and the resultant fibers had mechanical properties comparable to those of commercial fibers. The surface areas and nitrogen contents of the ACFs, obtained hereby were 740-860 m{sup 2}/g and 4-5.6%, respectively, at around 50 wt% of burn-off. FT-IR and XPS analyses identified the surface oxygen and nitrogen functional groups on the stabilized and activated fibers. The ACFs from isoquinoline pitch (IQP-ACF) exhibited higher basicity (l.3 meq/g) than commercial ACFs of similar surface areas (0.68 and 0.25 meq/g for PAN (FE-300) and coal tar pitch (OG-8A) based ACFs, respectively) due to a higher basic nitrogen content on the surface. The activation appears to expose basic nitrogen atoms, which were located under the surface. The basicity of ACF from quinoline pitch (QP-ACF) was much lower than that of IQP-ACF, however, QP-ACF adsorbed 74 mg/g of SO2, which was 1.4 and 2.3 times higher than that over FE-300 and OG-8A. In contrast, IQP-ACFs showed less adsorption of SO2 than that of QP-ACF and FE-300, but more than that of OG-8A. Oxidation activity of ACF surface may participate in the adsorption of SO2 in the form of SO3 or H2SO4. The oxygen functional groups under the influence of neighboring nitrogen atoms may be the active sites for the oxidative adsorption. 15 refs., 8 figs., 4 tabs.

  8. Water Filtration Using Plant Xylem

    Lee, Jongho; Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

    2013-01-01

    Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees - a readily available, inexpensive, biodegradable, and disposable material - can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings.

  9. Magnetic filtration of precipitated magnetite

    It has been established that treatment of iron-rich alpha contaminated effluent streams by precipitating the iron as ferric floc or magnetite is an effective method of actinide removal. The work reported here shows the effect of four major parameters on the efficiency of the magnetic separation process. These are, the magnetic field strength, the structure of the matrix, the linear velocity of the magnetite suspension during filtration, and the chemical composition of the effluent stream from which magnetite is precipitated. (U.K.)

  10. Gradient Clogging in Depth Filtration

    Datta, S.; Redner, S.

    1998-01-01

    We investigate clogging in depth filtration, in which a dirty fluid is ``cleaned'' by the trapping of dirt particles within the pore space during flow through a porous medium. This leads to a gradient percolation process which exhibits a power law distribution for the density of trapped particles at downstream distance x from the input. To achieve a non-pathological clogging (percolation) threshold, the system length L should scale no faster than a power of ln w, where w is the width. Non-tri...

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

    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.

  12. Hydrogen storage capacity of lithium-doped KOH activated carbons

    Highlights: • The hydrogen adsorption of lithium-doped KOH activated carbons has been studied. • Lithium doping improves their hydrogen adsorption affinity. • Lithium doping is more effective for materials with micropores of 0.8 nm or smaller. • Lithium reagent can alter the pore structure, depending on the raw material. • Optimizing the pore size and functional group is needed for better hydrogen uptake. - Abstract: The authors have studied the hydrogen adsorption performance of several types of lithium-doped KOH activated carbons. In the case of activated cokes, lithium doping improves their hydrogen adsorption affinity from 5.02 kg/m3 to 5.86 kg/m3 at 303 K. Hydrogen adsorption density increases by around 17% after lithium doping, likely due to the fact that lithium doping is more effective for materials with micropores of 0.8 nm or smaller. The effects of lithium on hydrogen storage capacity vary depending on the raw material, because the lithium reagent can react with the material and alter the pore structure, indicating that lithium doping has the effect of plugging or filling the micropores and changing the structures of functional groups, resulting in the formation of mesopores. Despite an observed decrease in hydrogen uptake, lithium doping was found to improve hydrogen adsorption affinity. Lithium doping increases hydrogen uptake by optimizing the pore size and functional group composition

  13. Toxicity of carbon nanotubes to the activated sludge process

    The discharge of carbon nanotubes (CNTs) from industrial waste or disposal of such materials from commercial and/or domestic use will inevitably occur with increasing production and enter into wastewater treatment facilities with unknown consequences. Therefore, a better knowledge of the toxicity of CNTs to biological processes in wastewater treatment will be critical. This study examined the toxicity of multi-walled carbon nanotubes (MWCNTs) on the microbial communities in activated sludge. A comparative study using the activated sludge respiration inhibition test was performed on both unsheared mixed liquor and sheared mixed liquor to demonstrate the potential toxicity posed by MWCNTs and to illustrate the extent of extracellular polymeric substances (EPS) in protecting the microorganisms from the toxicity of CNTs. Respiration inhibition was observed for both unsheared and sheared mixed liquor when MWCNTs were present, however, greater respiration inhibition was observed for the sheared mixed liquor. The toxicity observed by the respiration inhibition test was determined to be dose-dependent; the highest concentration of MWCNTs exhibited the highest respiration inhibition. Scanning Electron Microscopy (SEM) images demonstrated direct physical contact between MWCNTs and activated sludge flocs.

  14. Copper on activated carbon for catalytic wet air oxidation

    Nora Dolores Martínez

    2009-03-01

    Full Text Available Textile industry is an important source of water contamination. Some of the organic contaminants cannot be eliminated by nature in a reasonable period. Heterogeneous catalytic wet air oxidation is one of the most effective methods to purify wastewater with organic contaminants. In this work, catalysts based on copper supported on activated carbon were synthesized. The activated carbons were obtained from industrial wastes (apricot core and grape stalk of San Juan, Argentina. These were impregnated with a copper salt and thermically treated in an inert atmosphere. Analysis of specific surface, pore volume, p zc, acidity, basicity and XRD patterns were made in order to characterize the catalysts. The catalytic activity was tested in the oxidation of methylene blue (MB and polyvinyl alcohol (PVA in aqueous phase with pure oxygen. Reaction tests were carried out in a Parr batch reactor at different temperatures, with a 0.2 MPa partial pressure of oxygen. The amount of unconverted organics was measured by spectrophotometry. Higher temperatures were necessary for the degradation of PVA compared to those for methylene blue.

  15. Activated carbon nanofiber webs made by electrospinning for capacitive deionization

    Activated carbon fiber (ACF) webs with a non-woven multi-scale texture were fabricated from polyacrylonitrile (PAN), and their electrosorption performance in capacitive deionization for desalination was investigated. PAN nanofibers were prepared by electrospinning, followed by oxidative stabilization and activation with carbon dioxide at 750–900 °C, resulting in the ACF webs that were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and nitrogen adsorption. The results show that the as-made ACFs have a specific surface area of 335–712 m2/g and an average nanofiber diameter of 285–800 nm, which can be tuned by varying the activation temperature. With the ACF webs as an electrode, an electrosorption capacity as high as 4.64 mg/g was achieved on a batch-type electrosorptive setup operated at 1.6 V. The ACF webs made by electrospinning are of potential as an excellent electrode material for capacitive deionization for desalination.

  16. Effect of activation agents on the surface chemical properties and desulphurization performance of activated carbon

    2010-01-01

    Flue gas pollution is a serious environmental problem that needs to be solved for the sustainable development of China.The surface chemical properties of carbon have great influence on its desulphurization performance.A series of activated carbons (ACs) were prepared using HNO3,H2O2,NH3·H2O and steam as activation agents with the aim to introduce functional groups to carbon surface in the ACs preparation process.The ACs were physically and chemically characterized by iodine and SO2 adsorption,ultimate analysis,Boehm titration,and temperature-programmed reduction (TPR).Results showed that the iodine number and desulphurization capacity of NH3·H2O activated carbon (AC-NH3) increase with both activation time,and its desulphurization capacity also increases with the concentration of activation agent.However,HNO3 activated carbon (AC-HNO3) and H2O2 activated carbon (AC-H2O2) exhibit more complex behavior.Only their iodine numbers increase monotonously with activation time.Compared with steam activated AC (AC-H2O),the nitrogen content increases 0.232% in AC-NH3 and 0.077% in AC-HNO3.The amount of total basic site on AC-HNO3 is 0.19 mmol·g-1 higher than that on AC-H2O.H2O2 activation introduces an additional 0.08 mmol·g-1 carboxyl groups to AC surface than that introduced by steam activation.The desulphurization capacity of ACs in simulate flue gas desulphurization decreases as follows: AC-NH3 > AC-HNO3 > AC-H2O2 > AC-H2O.This sequence is in accord with the SO2 catalytic oxidation/oxidation ratio in the absence of oxygen and the oxidation property reflected by TPR.In the presence of oxygen,all adsorbed SO2 on ACs can be oxidized into SO3.The desulphurization capacity increases differently according to the activation agents;the desulphurization capacity of AC-NH3 and AC-HNO3 improves by 4.8 times,yet AC-H2O increases only by 2.62 as compared with the desulphurization of corresponding ACs in absence of oxygen.

  17. Lithium carbonate tablets. Preparation techniques influence over active ingredient liberation

    Lithium carbonate tablets, prepared using wet and dry granulation, were assessed in vitro so as to determine the active ingredient dissolution. In this study, standardized formulations were used and developed with usual adjuvants (lactose - maize starch). Parallel to the dissolution testing. The influence of the preparation process over some physical characteristics (hardness, friability and disintegration) was also analysed. Although a better performance was observed of tables prepared using dry granulation, the authors concluded that the wet process is more suitable in preparing tables with the mentioned drug. (author)

  18. Activated carbon is an electron-conducting amphoteric ion adsorbent

    Biesheuvel, P M

    2015-01-01

    Electrodes composed of activated carbon (AC) particles can desalinate water by ion electrosorption. To describe ion electrosorption mathematically, accurate models are required for the structure of the electrical double layers (EDLs) that form within electrically charged AC micropores. To account for salt adsorption also in uncharged ACs, an "attraction term" was introduced in modified Donnan models for the EDL structure in ACs. Here it will be shown how instead of using an attraction term, chemical information of the surface structure of the carbon-water interface in ACs can be used to construct an alternative EDL model for ACs. This EDL model assumes that ACs contain both acidic groups, for instance due to carboxylic functionalities, and basic groups, due to the adsorption of protons to the carbon basal planes. As will be shown, this "amphoteric Donnan" model accurately describes various data sets for ion electrosorption in ACs, for solutions of NaCl, of CaCl2, and mixtures thereof, as function of the exter...

  19. Activated carbon produced from Sasol-Lurgi gasifier pitch and its application as electrodes in supercapacitors

    A. Alonso; Ruiz Ruiz, Vanesa; Blanco Rodríguez, Clara; Santamaría Ramírez, Ricardo; Granda Ferreira, Marcos; Menéndez López, Rosa María; Jager, S.G.E. de

    2006-01-01

    [EN] A pyrolysis product derived from Sasol-Lurgi gasifier pitch was activated using different proportions of KOH. The increase of the amount of KOH used for activation caused the activation degree of the carbons to increase very significantly. The activated carbons obtained using lower amounts of KOH were mainly microporous, while the amount of mesopores developed in the samples progressively increased for the carbons activated with higher proportions of KOH. The gravimetric specific capacit...

  20. Relation between interfacial energy and adsorption of organic micropollutants onto activated carbon

    De Ridder, David J.

    2013-03-01

    The adsorption efficacy of 16 pharmaceuticals on six different activated carbons is correlated to the thermodynamic work of adhesion, which was derived following the surface tension component approach. Immersion calorimetry was used to determine the surface tension components of activated carbon, while contact angle measurements on compressed plates were used to determine these for solutes. We found that the acid-base surface tension components of activated carbon correlated to the activated carbon oxygen content. Solute-water interaction correlated well to their solubility, although four solutes deviated from the trend. In the interaction between solute and activated carbon, van der Waals interactions were dominant and explained 65-94% of the total interaction energy, depending on the hydrophobicity of the activated carbon and solute. A reasonable relationship (r2 > 70) was found between the calculated work of adhesion and the experimentally determined activated carbon loading. © 2012 Elsevier Ltd. All rights reserved.

  1. The removal of endocrine disrupting compounds, pharmaceutically activated compounds and cyanobacterial toxins during drinking water preparation using activated carbon--a review.

    Delgado, Luis F; Charles, Philippe; Glucina, Karl; Morlay, Catherine

    2012-10-01

    This paper provides a review of recent scientific research on the removal by activated carbon (AC) in drinking water (DW) treatment of 1) two classes of currently unregulated trace level contaminants with potential chronic toxicity-pharmaceutically activate compounds (PhACs) and endocrine disrupting compounds (EDCs); 2) cyanobacterial toxins (CyBTs), which are a group of highly toxic and regulated compounds (as microcystin-LR); and 3) the above mentioned compounds by the hybrid system powdered AC/membrane filtration. The influence of solute and AC properties, as well as the competitive effect from background natural organic matter on the adsorption of such trace contaminants, are also considered. In addition, a number of adsorption isotherm parameters reported for PhACs, EDCs and CyBTs are presented herein. AC adsorption has proven to be an effective removal process for such trace contaminants without generating transformation products. This process appears to be a crucial step in order to minimize PhACs, EDCs and CyBTs in finished DW, hence calling for further studies on AC adsorption removal of these compounds. Finally, a priority chart of PhACs and EDCs warranting further study for the removal by AC adsorption is proposed based on the compounds' structural characteristics and their low removal by AC compared to the other compounds. PMID:22885596

  2. Pig manure treatment and purification by filtration.

    Makara, A; Kowalski, Z

    2015-09-15

    This study aimed to develop a new, complex pig manure treatment and filtration process. The final scheme, called the AMAK process, comprised the following successive steps: mineralization with mineral acids, alkalization with lime milk, superphosphate addition, a second alkalization, thermal treatment, and pressure filtration. The proposed method produced a filtrate with 95%, 80%, and 96% reductions in chemical oxygen demand, nitrogen content, and phosphorus content, respectively. An advantage of the proposed method was that it incorporated a crystalline phase into the solid organic part of the manure, which enabled high filtration rates (>1000 kg m(-2) h(-1)) and efficient separation. The process also eliminated odor emissions from the filtrate and sediment. The treated filtrate could be used to irrigate crops or it could be further treated in conventional biological wastewater treatment plants. The sediment could be used for producing mineral-organic fertilizer. The AMAK process is inexpensive, and it requires low investment costs. PMID:26197426

  3. Cake creep during filtration of flocculated manure

    Christensen, Morten Lykkegaard; Keiding, Kristian

    distribution of N and P on the fields. Filtration is a useful method for such a separation. Furthermore, chemicals can be added to flocculate the solids and thereby increase the filterability i.e. the specific filter-cake resistance can be reduced from 1015 m/kg to 1011 m/kg. Both the amount of added chemicals...... suggested that the discrepancy between the filtration theory and the observed filtration behaviour is due to a time-dependent collapse of the formed cake (creep). This can also explain the observed behaviour when flocculated manure is filtered. The filtration data can be simulated if cake creep is adopted...... in the filtration model. The calculation shows that the specific filter-cake resistance increases by a factor of 3 during the filtration. Thus, the impact of cake creep is significant when organic materials such as manure are filtered....

  4. Current-induced strength degradation of activated carbon spheres in carbon supercapacitors

    Sun, Yuan; Chen, Rong; Lipka, Stephen M.; Yang, Fuqian

    2016-05-01

    Activated carbon microspheres (ACSs), which are prepared using hydrothermal synthesis and ammonia activation, are used as the active materials in the anode and cathode of electric double layer capacitors (EDLCs). The ACS-based EDLCs of symmetrical electrodes exhibit good stability and a high degree of reversibility over 2000 charge-discharge cycles for electric current up to 10 A g‑1. The ACSs maintain a nongraphitized carbon structure after over 2000 charge-discharge cycles. Nanoindentation experiments are performed on the ACSs, which are electrochemically cycled in a voltage window of 0–1 V at three electric currents of 0.5, 5, and 10 A g‑1. For the same indentation load, both the contact modulus and indentation hardness of the ACSs decrease with the increase of the electric current used in the electrical charging and discharging. These results suggest that there exists strength degradation introduced by the electric current. A larger electric current will cause more strength degradation than a smaller electric current.

  5. Side Stream Filtration for Cooling Towers

    None

    2012-10-20

    This technology evaluation assesses side stream filtration options for cooling towers, with an objective to assess key attributes that optimize energy and water savings along with providing information on specific technology and implementation options. This information can be used to assist Federal sites to determine which options may be most appropriate for their applications. This evaluation provides an overview of the characterization of side stream filtration technology, describes typical applications, and details specific types of filtration technology.

  6. Comparative study of carbon nanotubes and granular activated carbon: Physicochemical properties and adsorption capacities.

    Gangupomu, Roja Haritha; Sattler, Melanie L; Ramirez, David

    2016-01-25

    The overall goal was to determine an optimum pre-treatment condition for carbon nanotubes (CNTs) to facilitate air pollutant adsorption. Various combinations of heat and chemical pre-treatment were explored, and toluene was tested as an example hazardous air pollutant adsorbate. Specific objectives were (1) to characterize raw and pre-treated single-wall (SW) and multi-wall (MW) CNTs and compare their physical/chemical properties to commercially available granular activated carbon (GAC), (2) to determine the adsorption capacities for toluene onto pre-treated CNTs vs. GAC. CNTs were purified via heat-treatment at 400 °C in steam, followed by nitric acid treatment (3N, 5N, 11N, 16N) for 3-12 h to create openings to facilitate adsorption onto interior CNT sites. For SWNT, Raman spectroscopy showed that acid treatment removed impurities up to a point, but amorphous carbon reformed with 10h-6N acid treatment. Surface area of SWNTs with 3 h-3N acid treatment (1347 m(2)/g) was higher than the raw sample (1136 m(2)/g), and their toluene maximum adsorption capacity was comparable to GAC. When bed effluent reached 10% of inlet concentration (breakthrough indicating time for bed cleaning), SWNTs had adsorbed 240 mg/g of toluene, compared to 150 mg/g for GAC. Physical/chemical analyses showed no substantial difference for pre-treated vs. raw MWNTs. PMID:26476807

  7. Molecular simulation of multi-component adsorption processes related to carbon capture in a high surface area, disordered activated carbon

    Di Biase, Emanuela; Sarkisov, Lev

    2015-01-01

    We employ a previously developed model of a high surface area activated carbon, based on a random packing of small fragments of a carbon sheet, functionalized with hydroxyl surface groups, to explore adsorption of water and multicomponent mixtures under conditions representing typical carbon capture processes. Adsorption of water is initialized and proceeds through the growth of clusters around the surface groups, in a process predominantly governed by hydrogen bond interactions. In contrast,...

  8. Impacts of extreme flooding on riverbank filtration water quality.

    Ascott, M J; Lapworth, D J; Gooddy, D C; Sage, R C; Karapanos, I

    2016-06-01

    Riverbank filtration schemes form a significant component of public water treatment processes on a global level. Understanding the resilience and water quality recovery of these systems following severe flooding is critical for effective water resources management under potential future climate change. This paper assesses the impact of floodplain inundation on the water quality of a shallow aquifer riverbank filtration system and how water quality recovers following an extreme (1 in 17 year, duration >70 days, 7 day inundation) flood event. During the inundation event, riverbank filtrate water quality is dominated by rapid direct recharge and floodwater infiltration (high fraction of surface water, dissolved organic carbon (DOC) >140% baseline values, >1 log increase in micro-organic contaminants, microbial detects and turbidity, low specific electrical conductivity (SEC) 400% baseline). A rapid recovery is observed in water quality with most floodwater impacts only observed for 2-3 weeks after the flooding event and a return to normal groundwater conditions within 6 weeks (lower fraction of surface water, higher SEC, lower DOC, organic and microbial detects, DO). Recovery rates are constrained by the hydrogeological site setting, the abstraction regime and the water quality trends at site boundary conditions. In this case, increased abstraction rates and a high transmissivity aquifer facilitate rapid water quality recoveries, with longer term trends controlled by background river and groundwater qualities. Temporary reductions in abstraction rates appear to slow water quality recoveries. Flexible operating regimes such as the one implemented at this study site are likely to be required if shallow aquifer riverbank filtration systems are to be resilient to future inundation events. Development of a conceptual understanding of hydrochemical boundaries and site hydrogeology through monitoring is required to assess the suitability of a prospective riverbank filtration

  9. Evaluation of Hydrochemical and Hydrogeological Characteristics of Riverbank Filtration Aquifer

    Ko, K.; Suk, H.

    2009-12-01

    The riverbank filtration is a feasible method to secure potable water resources where surface water cannot be directly provided. Bank filtrate water has been recently recognized as an alternative water resource around Nakdong River area in South Korea. The high manganese and iron, which are mainly produced from microbial reduction of aquifer, are frequently observed problems in bank filtrated water and the causes of them have been studied by restricted researchers. To understand the source and occurrence of manganese and iron in bank filtration water, we examined the hydrochemical and isotopic characteristics of water and the features of aquifer sediments which are collected from two bank filtration application area, Ddan Island and Jeungsan-ri. Most of waters collected from Ddan island have Ca-(Cl+SO4) type and the variation of water chemistry are mainly induced by anions such as bicarbonate and nitrate that are sensitive to the redox condition of aquifer. Nitrate is not detected in deep (>20m) water with low dissolved oxygen (preventing the inflow of river water to the production wells. In addition, the aquifer underneath the clay layer is under reducing condition, which might cause the high concentration of reduced iron and manganese. Manganese in the sediments was in the form of easily reducible and exchangeable phase but iron were present dominantly in the form of reducible and carbonate phase from the modified sequential analysis. This indicates the different reactivity of manganese and iron for redox state. From the above results, manganese was extracted under weakly reduced condition but iron was extracted strong reducing condition.

  10. Microbial activity in granular activated carbon filters in drinking water treatment

    Knezev, A.

    2015-01-01

    The investigations described are carried out to analyse the microbiological processes in relation to the GAC characteristics and the removal of natural organic matter (NOM) in Granular Activated Carbon filters (GACFs) in water treatment. The main goal of the study was to obtain a qualitative descrip

  11. ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

    Martino, C.; Herman, D.; Pike, J.; Peters, T.

    2014-06-05

    Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

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

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

  13. Projective Dimension in Filtrated K-Theory

    Bentmann, Rasmus Moritz

    2013-01-01

    Under mild assumptions, we characterise modules with projective resolutions of length n∈N in the target category of filtrated K-theory over a finite topological space in terms of two conditions involving certain Tor -groups. We show that the filtrated K-theory of any separable C∗dash-algebra over......-point space, the filtrated K-theory of which has projective dimension 3. Finally, as an application of our investigations, we exhibit Cuntz-Krieger algebras which have projective dimension 2 in filtrated K-theory over their respective primitive spectrum....

  14. Air filtration and indoor air quality

    Bekö, Gabriel

    decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air...... contradictions should motivate manufacturers and researchers to develop new efficient filtration techniques and/or improve the existing ones. Development of low polluting filtration techniques, which are at the same time easy and inexpensive to maintain is the way forward in the future....

  15. Activation-free printed carbon nanotube field emitters

    When a carbon nanotube paste is formulated based on highly functional hyperbranched polymers such as dipentaerythritol hexaacrylate, the volume shrinkage during thermal curing builds up internal stress that generates microcrack patterns on the printed surface. The nanotubes exposed in the cracks emit electrons successfully at such an extremely low electric field as 0.5 V μm-1, and reach 25.5 mA cm-2 of current density at 2 Vμm-1 from an optimized paste concerning mainly the size and spatial uniformity of the crack. In addition to the superior field emission properties with low manufacturing cost, this activation-free technology can provide a minimized nanohazard in the device fabrication process, compared to those conventional activation technologies developing serious nanoflakes by using destructive methods.

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

    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.

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

    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. PMID:25078809

  18. Adsorption of Phenols and Chlorophenols in Wastewaters on Activated Carbon and Dried Activated Sludge

    YENER, Jülide

    1999-01-01

    One of the methods used for removal of phenols and chlorophenols from the wastewaters of petroleum refineries, coke, medicine, dye, plastics, pesticide, insecticide, and paper industry is the adsorption process. In this study, adsorption of phenol, o-chlorophenol and p-chlorophenol from aqueous solutions on to granular activated carbon and dried activated sludge was investigated as a function of pH, initial pollutant concentration and functional groups. Effects of these parameters on...

  19. Leachate Treatment by Batch Decant Activated Sludge Process and Powdered Activated Carbon Addition

    Y Hashempur; R Rezaei Kalantary; Jaafarzadeh, N.; Jorfi, S.

    2009-01-01

    "n "nBackgrounds and Objectives: Direct biodegradation of landfill leachate is too difficult because of high concentrations of COD and NH3 and also the presence of toxic compounds. The main objective of this study was to application of Strurvite precipitation as a pretreatment stage, in order to remove inhibitors of biodegradation before the batch decant activated sludge process with addition of powdered activated carbon (PAC)."nMaterials and Methods: Strurvite precipitated leachate was intro...

  20. Kinetic and Equilibrium Studies for the Removal of Bromate by the Modified Activated Carbon

    Muqing Qiu

    2015-03-01

    Full Text Available Bromate which was formed bromide dissolved in water during the ozonation process, is carcinogenic and mutagenic to humans. To avoid bromate damage, many countries strictly control its concentration in drinking water. Activated carbon is an effective adsorbent material widely used in water treatment. In order to enhance the adsorption of bromate ion on activated carbon, the modified activated carbon was obtained from granular activated carbon by chemical activation using cationic surfactant as an activator. The adsorption characteristics of bromate ion on the modified activated carbon were investigated through adsorption experiments. The effects of temperature, pH in solution, contact time and initial bromate concentration on bromate adsorption by the modified activated carbon were investigated. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption. Kinetic adsorption data were analyzed by the pseudo-first-order kinetic model and the pseudo-second-order model, respectively.

  1. Efficient Filtration of Effluent Organic Matter by Polycation-Clay Composite Sorbents: Effect of Polycation Configuration on Pharmaceutical Removal.

    Shabtai, Itamar A; Mishael, Yael G

    2016-08-01

    Hybrid polycation-clay composites, based on methylated poly vinylpyridinium, were optimized as sorbents for secondary effluent organic matter (EfOM) including emerging micropollutants. Composite structure was tuned by solution ionic strength and characterized by zeta potential, FTIR, X-ray diffraction, and thermal gravimetric analyses. An increase in ionic strength induced a transition from a train to a loops and tails configuration, accompanied by greater polycation adsorption. Composite charge reversal (zeta potential -18 to 45 mV) increased the adsorption of EfOM and humic acid (HA), moderately and sharply, respectively, suggesting electrostatic and also nonspecific interactions with EfOM. Filtration of EfOM by columns of positively charged composites was superior to that of granular activated carbon (GAC). The overall removal of EfOM was most efficient by the composite with a train configuration. Whereas a composite with a loops and tails configuration was beneficial for the removal of the anionic micropollutants diclofenac, gemfibrozil and ibuprofen from EfOM. These new findings suggest that the loops and tails may offer unique binding sites for small micropollutants which are overseen by the bulk EfOM. Furthermore, they may explain our previous observations that in the presence of dissolved organic matter, micropollutant filtration by GAC columns was reduced, while their filtration by composite columns remained high. PMID:27397603

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

    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.

  3. 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

    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.

  4. Influence of activated carbon characteristics on toluene and hexane adsorption: Application of surface response methodology

    Izquierdo Pantoja, María Teresa; Yuso, A. M. de; Valenciano, Raquel; Rubio Villa, Begoña; Pino, María Rosa

    2013-01-01

    The objective of this study was to evaluate the adsorption capacity of toluene and hexane over activated carbons prepared according an experimental design, considering as variables the activation temperature, the impregnation ratio and the activation time. The response surface methodology was applied to optimize the adsorption capacity of the carbons regarding the preparation conditions that determine the physicochemical characteristics of the activated carbons. The methodology of preparation...

  5. Activated carbon derived from marine Posidonia Oceanica for electric energy storage

    N. Boukmouche; N. Azzouz; L. Bouchama; J.P. Chopart; Y. Bouznit

    2014-01-01

    In this paper, the synthesis and characterization of activated carbon from marine Posidonia Oceanica were studied. The activated carbon was prepared by a simple process namely pyrolysis under inert atmosphere. The activated carbon can be used as electrodes for supercapacitor devices. X-ray diffraction result revealed a polycrystalline graphitic structure. While scanning electron microscope investigation showed a layered structure with micropores. The EDS analysis showed that the activated car...

  6. Activated carbons from African oil palm waste shells and fibre for hydrogen storage

    Liliana Giraldo; Maria Fernanda González-Navarro; Juan Carlos Moreno-Piraján

    2013-01-01

    We prepared a series of activated carbons by chemical activation with two strong bases in-group that few use, and I with waste from shell and fibers and oil-palm African. Activated carbons are obtained with relatively high surface areas (1605 m2/g). We study the textural and chemical properties and its effect on hydrogen storage. The activated carbons obtained from fibrous wastes exhibit a high hydrogen storage capacity of 6.0 wt % at 77 K and 12 bar.

  7. The filtration activity of a serpulid polychaete population ( Ficopomatus enigmaticus (Fauvel) and its effects on water quality in a coastal marina

    Davies, B. R.; Stuart, V.; de Villiers, M.

    1989-12-01

    An estimate of the total standing stock of Ficopomatus enigmaticus (Fauvel) in the Marina da Gama, Zandvlei, near Cape Town was made, and some aspects of the animals' filter-feeding behaviour investigated. Working on values of 5·23 g dry mass of worm (excluding tube) m -2 on the submerged aquatic plant Potamogeton pectinatus L., plus 84·9 g m -2 on the canal walls, the total standing stock of the serpulid was estimated at 2·88±2·24 t (1·4 t on Potamogeton; 1·48 t on canal walls). At the average particle concentrations of Marina water of 5·27 mg l -1, the clearnace rate of F. enigmaticus was 8·59 ml mg -1 worm h -1, resulting in an ingestion rate of 45·27 mg mg -1 worm h -1 of particles in the size range 2-16 μm. Clearance and ingestion rates both increased in direct proportion to food concentration. Using estimates of total standing stocks within the Marina, the F. enigmaticus population clears 2·47 × 10 7 l of water h -1 and consumes 1·3 × 10 8 mg of particles h -1 in the 2-16 μm size range. Thus, the entire volume of the Marina will be filtered in 26·1 h through the activities of this animal alone, illustrating its importance for the maintenance of water quality within this moderately polluted system.

  8. Cross-flow micro-filtration using ceramic membranes

    Pressurized Heavy Water Reactors have a system devoted to the purification and upgrading of the collected heavy water leaks. The purification train is fed with different degradation ratios (D2O/H2O), activities and impurities. The water is distilled in a packed bed column filled with a mesh type packing. With the purpose of minimizing the column stack corrosion, the water is pre-treated in a train consisting on an activated charcoal bed-strong cationic-anionic resin and a final polishing anionic bed resin. Traces of oils are retained by the charcoal bed but some of them pass through and could be responsible for the resins fouling. The process of micro filtration using ceramic materials is particularly applied to the treatment of waters with oil micro droplets. We describe the development stages of single and double layer filtration ceramic tubes, their characterization and the adaptation to test equipment. The efficiency was evaluated by means of tangential ('cross-flow') filtration of aqueous solutions containing dodecane at the micrograms per ml concentration level. This compound simulates the properties of a typical oil contaminant. A 100-fold reduction in the amount of dodecane in water was observed after the filtration treatment. (author)

  9. Effects of Surface Area and Flow Rate on Marine Bacterial Growth in Activated Carbon Columns

    Shimp, Robert J.; Pfaender, Frederic K.

    1982-01-01

    The colonization of granular activated carbon columns by bacteria can have both beneficial and potentially detrimental consequences. Bacterial growth on the carbon surface can remove adsorbed organics and thus partially regenerate the carbon bed. However, growth can also increase the levels of bacteria in the column effluents, which can adversely affect downstream uses of the treated water. This study of a sand column and several activated carbon columns demonstrated that considerable marine ...

  10. Effect of textural property of coconut shell-based activated carbon on desorption activation energy of benzothiophene

    Moxin YU; Zhong LI; Hongxia XI; Qibin XIA; Shuwen WANG

    2008-01-01

    In this work,the effect of the textural property of activated carbons on desorption activation energy and adsorption capacity for benzothiophene (BT) was investi-gated.BET surface areas and the textural parameters of three kinds of the activated carbons,namely SY-6,SY-13 and SY-19,were measured with an ASAP 2010 instru-ment.The desorption activation energies of BT on the activated carbons were determined by temperature-pro-grammed desorption (TPD).Static adsorption experi-ments were carried out to determine the isotherms of BT on the activated carbons.The influence of the textural property of the activated carbons on desorption activa-tion energy and the adsorption capacity for BT was dis-cussed.Results showed that the BET surface areas of the activated carbons,SY-6,SY-13 and SY-19 were 1106,diameters were 1.96,2.58 and 2.16 nm,respectively.The TPD results indicated that the desorption activation energy of BT on the activated carbons,SY-6,SY-19 and SY-13 were 58.84,53.02 and 42.57 KJ/mol,respectively.The isotherms showed that the amount of BT adsorbed on the activated carbons followed the order of SY-6 > SY-19 > SY-13.The smaller the average pore diameter of the activated carbon,the stronger its adsorption for BT and the higher the activation energy required for BT desorp-tion on its surface.The Freundlich adsorption isotherm model can be properly used to formulate the adsorption behavior of BT on the activated carbons.

  11. Effect of the nature the carbon precursor on the physico-chemical characteristics of the resulting activated carbon materials

    Carbon materials, including amorphous carbon, graphite, carbon nanospheres (CNSs) and different types of carbon nanofibers (CNFs) [platelet, herringbone and ribbon], were chemically activated using KOH. The pore structure of carbon materials was analyzed using N2/77 K adsorption isotherms. The presence of oxygen groups was analyzed by temperature programmed desorption in He and acid-base titration. The structural order of the materials was studied by X-ray diffraction and temperature programmed oxidation. The morphology and diameter distribution of CNFs and CNSs were characterized by transmission electron microscopy. The materials were also characterized by temperature-desorption programmed of H2 and elemental composition. The ways in which the different structures were activated are described, showing the type of pores generated. Relationships between carbon yield, removed carbon, activation degree and graphitic character were also examined. The oxygen content in the form of oxygen-containing surface groups increased after the activation giving qualitative information about them. The average diameter of both CNFs and CNSs was decreased after the activation process as consequence of the changes produced on the material surface.

  12. Comparison of various sources of high surface area carbon prepared by different types of activation

    Activated carbon has been known as an excellent adsorbent and is widely used due to its large adsorption capacity. Activation condition and types of activation influence the surface area and porosity of the activated carbon produced. In this study, palm kernel shells and commercially activated carbon were used. To convert palm kernel shells into coal, two methods were employed, namely chemical activation and physical activation. For chemical activation, two activating agents, zinc chloride and potassium carbonate, were used. The activated carbons were analyzed using Fourier Transform Infrared (FTIR) spectroscopy, single point BET and free emission scanning electron microscopy (FESEM). The commercial activated carbon was also characterized. FTIR results indicate that all the palm kernel shells were successfully converted to carbon. Single point BET surface area of all the carbons prepared were obtained. From FESEM micrograph, the chemically activated palm kernel shells shows well highly defined cavities and pores. This study also shows that palm kernel shells can be used to be a better source of high surface area carbon. (author)

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

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

    2007-01-01

    Activated carbons derived from oil palm empty fruit bunches (EFB) were investigated to find the suitability of its application for removal of phenol in aqueous solution through adsorption process. Two types of activation namely; thermal activation at 300, 500 and 800 degrees C and physical activation at 150 degrees C (boiling treatment) were used for the production of the activated carbons. A control (untreated EFB) was used to compare the adsorption capacity of the activated carbons produced from these processes. The results indicated that the activated carbon derived at the temperature of 800 degrees C showed maximum absorption capacity in the aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon at 800 degrees C. It was observed that the adsorption capacity was higher at lower values of pH (2-3) and higher value of initial concentration of phenol (200-300 mg/L). The equilibrium data fitted better with the Freundlich adsorption isotherm compared to the Langmuir. Kinetic studies of phenol adsorption onto activated carbons were also studied to evaluate the adsorption rate. The estimated cost for production of activated carbon from EFB was shown in lower price (USD 0.50/kg of activated carbon) compared the activated carbon from other sources and processes. PMID:17913162

  14. Preparation, characterization and photocatalytic activity of a novel composite photocatalyst: Ceria-coated activated carbon

    In the present work, a novel composite photocatalyst ceria-coated activated carbon (CCAC) was prepared by a facile method. The composite photocatalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and photocatalytic degradation of 4-chlorophenol (4-CP). A synergy effect for 4-CP degradation was observed because the activated carbon (AC) with strong adsorbent activity provided sites for the adsorption of 4-CP. Then, the adsorbed 4-CP can migrate continuously onto the surface of ceria particles and then degraded at there. Hydroquinone (HQ) and benzoquinone (BQ) were found to be the main intermediates of the photocatalytic 4-CP degradation with ceria or CCAC by HPLC measurement. The results suggested that the same reaction mechanism occurred in the presence of ceria or titania.

  15. Characterization of Microporous Activated Carbon Electrodes for Electric Double-layer Capacitors

    MENG Qing-han; LIU Ling; SONG Huai-he

    2004-01-01

    Activated carbons (ACs) with a wide range of surface areas were made from petroleum coke by means of KOH activation. The electrochemical characterization was carried out for several activated carbons used as polariz able electrodes of electric double-layer capacitors (EDLCs) in an aqueous electrolytic solution. The porous structures and electrochemical double-layer capacitance of the activated carbons were investigated by virtue of nitrogen gas adsorption and constant current cycling(CCC) methods. The relationship among the surface area, pore volume of the activated carbons and specific double-layer capacitance was discussed. It was found that the specific capacitance of ACs increased linearly with the increase of surface area. The presence of mesopores in the activated carbons with very high surface area(>2000 m2/g) was not very effective for them to be used as EDLCs. The influence of chemical characteristics of the activated carbons on the double layer formation could be considered to be negligible.

  16. Activated carbon from char obtained from vacuum pyrolysis of teak sawdust: pore structure development and characterization.

    Ismadji, S; Sudaryanto, Y; Hartono, S B; Setiawan, L E K; Ayucitra, A

    2005-08-01

    The preparation of activated carbon from vacuum pyrolysis char of teak sawdust was studied and the results are presented in this paper. The effects of process variables such as temperature and activation time on the pore structure of activated carbons were studied. The activated carbon prepared from char obtained by vacuum pyrolysis has higher surface area and pore volume than that from atmospheric pyrolysis char. The BET surface area and pore volume of activated carbon prepared from vacuum pyrolysis char were 1150 m2/g and 0.43 cm3/g, respectively. PMID:15792584

  17. Preparation and characterization of activated carbon from pistachio nut shells via microwave-induced chemical activation

    In this work, pistachio nut shell, a biomass residue abundantly available from the pistachio nut processing industries, was utilized as a feedstock for the preparation of activated carbon (PSAC) via microwave assisted KOH activation. The activation step was performed at the microwave input power of 600 W and irradiation time of 7 min. The porosity, functional and surface chemistry were featured by means of low temperature nitrogen adsorption, scanning electron microscopy and Fourier transform infrared spectroscopy. Result showed that the BET surface area, Langmuir surface area, and total pore volume of PSAC were 700.53 m2 g-1, 1038.78 m2 g-1 and 0.375 m3 g-1, respectively. The adsorptive property of PSAC was tested using methylene blue dye as the targeted adsorbate. Equilibrium data was best fitted by the Langmuir isotherm model, showing a monolayer adsorption capacity of 296.57 mg g-1. The study revealed the potentiality of microwave-induced activation as a viable activation method. -- Highlights: → Pistachio nut shell activated carbon (PSAC) was prepared via microwave assisted KOH activation. → The activation step was performed at the microwave input power of 600 W and irradiation time of 7 min. → BET surface area of PSAC was 700.53 m2/g. → Monolayer adsorption capacity of PSAC for MB was 296.57 mg/g.

  18. Hazard categorization of K Basin water filtration upgrade project

    This supporting document provides the hazards categorization for the K Basin Water Filtration Upgrade Project at K East. All activities associated with the project are less than Hazard Category 3, except for the handling of the ECO-ROK liners containing spent filter cartridges. All activities involving the handling of liners, containing spent cartridges, by monorail, forklift or mobile crane are classified as Hazard Category 3

  19. Removal of Heavy Metal Ions with Acid Activated Carbons Derived from Oil Palm and Coconut Shells

    Mokhlesur M. Rahman

    2014-05-01

    Full Text Available In this work, batch adsorption experiments were carried out to investigate the suitability of prepared acid activated carbons in removing heavy metal ions such as nickel(II, lead(II and chromium(VI. Acid activated carbons were obtained from oil palm and coconut shells using phosphoric acid under similar activation process while the differences lie either in impregnation condition or in both pretreatment and impregnation conditions. Prepared activated carbons were modified by dispersing hydrated iron oxide. The adsorption equilibrium data for nickel(II and lead(II were obtained from adsorption by the prepared and commercial activated carbons. Langmuir and Freundlich models fit the data well. Prepared activated carbons showed higher adsorption capacity for nickel(II and lead(II. The removal of chromium(VI was studied by the prepared acid activated, modified and commercial activated carbons at different pH. The isotherms studies reveal that the prepared activated carbon performs better in low concentration region while the commercial ones in the high concentration region. Thus, a complete adsorption is expected in low concentration by the prepared activated carbon. The kinetics data for Ni(II, Pb(II and Cr(VI by the best selected activated carbon fitted very well to the pseudo-second-order kinetic model.

  20. Carbon Dioxide Information Analysis Center: FY 1992 activities

    Cushman, R.M. [Oak Ridge National Lab., TN (United States). Carbon Dioxide Information Analysis Center; Stoss, F.W. [Tennessee Univ., Knoxville, TN (United States). Energy, Environment and Resources Center

    1993-03-01

    During the course of a fiscal year, Oak Ridge National Laboratory`s Carbon Dioxide Information Analysis Center (CDIAC) distributes thousands of specialty publications-numeric data packages (NDPs), computer model packages (CMPs), technical reports, public communication publications, newsletters, article reprints, and reference books-in response to requests for information related to global environmental issues, primarily those pertaining to climate change. CDIACs staff also provides technical responses to specific inquiries related to carbon dioxide (CO{sub 2}), other trace gases, and climate. Hundreds of referrals to other researchers, policy analysts, information specialists, or organizations are also facilitated by CDIAC`s staff. This report provides an account of the activities accomplished by CDIAC during the period October 1, 1991 to September 30, 1992. An organizational overview of CDIAC and its staff is supplemented by a detailed description of inquiries received and CDIAC`s response to those inquiries. As analysis and description of the preparation and distribution of numeric data packages, computer model packages, technical reports, newsletters, fact sheets, specialty publications, and reprints is provided. Comments and descriptions of CDIAC`s information management systems, professional networking, and special bilateral agreements are also described.

  1. Carbon Dioxide Information Analysis Center: FY 1991 activities

    Cushman, R.M.; Stoss, F.W.

    1992-06-01

    During the course of a fiscal year, Oak Ridge National Laboratory's Carbon Dioxide Information Analysis Center (CDIAC) distributes thousands of specially publications-numeric data packages (NDPs), computer model packages (CMPs), technical reports, public communication publications, newsletters, article reprints, and reference books-in response to requests for information related to global environmental issues, primarily those pertaining to climate change. CDIAC's staff also provides technical responses to specific inquiries related to carbon dioxide (CO{sub 2}), other trace gases, and climate. Hundreds of referrals to other researchers, policy analysts, information specialists, or organizations are also facilitated by CDIAC's staff. This report provides an account of the activities accomplished by CDIAC during the period October 1, 1990 to September 30, 1991. An organizational overview of CDIAC and its staff is supplemented by a detailed description of inquiries received and CDIAC's response to those inquiries. An analysis and description of the preparation and distribution of numeric data packages, computer model packages, technical reports, newsletters, factsheets, specially publications, and reprints is provided. Comments and descriptions of CDIAC's information management systems, professional networking, and special bilateral agreements are also described.

  2. Carbon Dioxide Information Analysis Center: FY 1991 activities

    Cushman, R.M.; Stoss, F.W.

    1992-06-01

    During the course of a fiscal year, Oak Ridge National Laboratory`s Carbon Dioxide Information Analysis Center (CDIAC) distributes thousands of specially publications-numeric data packages (NDPs), computer model packages (CMPs), technical reports, public communication publications, newsletters, article reprints, and reference books-in response to requests for information related to global environmental issues, primarily those pertaining to climate change. CDIAC`s staff also provides technical responses to specific inquiries related to carbon dioxide (CO{sub 2}), other trace gases, and climate. Hundreds of referrals to other researchers, policy analysts, information specialists, or organizations are also facilitated by CDIAC`s staff. This report provides an account of the activities accomplished by CDIAC during the period October 1, 1990 to September 30, 1991. An organizational overview of CDIAC and its staff is supplemented by a detailed description of inquiries received and CDIAC`s response to those inquiries. An analysis and description of the preparation and distribution of numeric data packages, computer model packages, technical reports, newsletters, factsheets, specially publications, and reprints is provided. Comments and descriptions of CDIAC`s information management systems, professional networking, and special bilateral agreements are also described.

  3. Active chemisorption sites in functionalized ionic liquids for carbon capture.

    Cui, Guokai; Wang, Jianji; Zhang, Suojiang

    2016-07-25

    Development of novel technologies for the efficient and reversible capture of CO2 is highly desired. In the last decade, CO2 capture using ionic liquids has attracted intensive attention from both academia and industry, and has been recognized as a very promising technology. Recently, a new approach has been developed for highly efficient capture of CO2 by site-containing ionic liquids through chemical interaction. This perspective review focuses on the recent advances in the chemical absorption of CO2 using site-containing ionic liquids, such as amino-based ionic liquids, azolate ionic liquids, phenolate ionic liquids, dual-functionalized ionic liquids, pyridine-containing ionic liquids and so on. Other site-containing liquid absorbents such as amine-based solutions, switchable solvents, and functionalized ionic liquid-amine blends are also investigated. Strategies have been discussed for how to activate the existent reactive sites and develop novel reactive sites by physical and chemical methods to enhance CO2 absorption capacity and reduce absorption enthalpy. The carbon capture mechanisms of these site-containing liquid absorbents are also presented. Particular attention has been paid to the latest progress in CO2 capture in multiple-site interactions by amino-free anion-functionalized ionic liquids. In the last section, future directions and prospects for carbon capture by site-containing ionic liquids are outlined. PMID:27243042

  4. Enhanced mercury ion adsorption by amine-modified activated carbon

    Zhu Jianzhong [Center of Environmental Sciences, Lincoln University of Missouri, Jefferson City, MO 65102 (United States); Yang, John, E-mail: yangj@lincolnu.edu [Center of Environmental Sciences, Lincoln University of Missouri, Jefferson City, MO 65102 (United States); Deng Baolin [Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO 65211 (United States)

    2009-07-30

    Mercury (Hg) is one of the most toxic metals found in water and sediments. In an effort to develop an effective adsorbent for aqueous Hg removal, activated carbon (AC) was modified with an amino-terminated organosilicon (3-aminopropyltriethoxysilane, APTES). Surface properties of the APTES-modified AC (MAC) were characterized by the scanning electron microscopy in conjunction with the energy-dispersive spectroscopy (SEM-EDS), the Fourier transform infrared spectroscopy (FT-IR), and potentiometry. The impacts of solvent, APTES concentration, reactive time and temperature on the surface modification were evaluated. The aqueous Hg adsorptive kinetics and capacity were also determined. Results demonstrated that the strong Hg-binding amine ligands were effectively introduced onto the AC surfaces through the silanol reaction between carbon surface functional groups (-COOH, -COH) and APTES molecules. The modification lowered the pH at the point of zero charge (pH{sub pzc}) to 4.54 from 9.6, favoring cation adsorption. MAC presented a faster rate of the Hg (II) adsorption and more than double adsorptive capacity as compared with AC.

  5. Filtration track membranes and their biomedical applications

    The characteristics of track filtration membranes has been performed. The investigation of radiation resistance has been carried out for different types of polymer foil used as a membrane material. Biomedical applications of track filtration membranes have been presented and discussed. 10 refs, 10 figs

  6. Monodromy weight filtration is independent of l

    Terasoma, Tomohide

    1998-01-01

    In this paper, we prove the l-independence of monodromy weight filtration for a geometrically smooth variety over an equicharacteristic local field. We also prove the l-independence for the geometric monodromy representation on the associated graded module of weight monodromy filtration.

  7. Adsorption of carbon dioxide by sodium hydroxide-modified granular coconut shell activated carbon in a fixed bed

    In the present work, commercial coconut shell activated carbon was impregnated with alkaline NaOH to investigate the efficiency of modified activated carbon for CO2 adsorption in a fixed-bed column adsorption system. The modification parameters, such as the NaOH concentration (24–48%) and dwelling time (1–4 h), were also investigated. The results showed that a 32% NaOH concentration with a 3 h dwelling time provided the best CO2 adsorption capacity. Later, the modified activated carbon was characterized by nitrogen adsorption–desorption, scanning electron microscopy and Fourier transform infrared spectroscopy. The effects of the CO2 % in the feed, the adsorption temperature, the feed flow rate and the amount of adsorbent in the column were investigated in the adsorption experiments. The maximum CO2 adsorption capacity in this study was 27.10 mg/g at 35 °C. This study also suggests that NaOH-modified activated carbon is a state-of-the-art adsorbent for CO2 adsorption. - Highlights: • Coconut shell activated carbon was impregnated with alkaline NaOH. • CO2 was adsorbed in a fixed-bed column adsorption system. • The effects of CO2 concentration, temperature, flow rate and dose are analyzed. • Regeneration of modified activated carbons was effectively tested for ten cycles

  8. Effect of Activated Carbon as a Support on Metal Dispersion and Activity of Ruthenium Catalyst for Ammonia Synthesis

    2002-01-01

    Ten kinds of activated carbon from different raw materials were used as supports to prepare ruthenium catalysts. N2 physisorption and CO chemisorption were carried out to investigate the pore size distribution and the ruthenium dispersion of the catalysts. It was found that the Ru dispersion of the catalyst was closely related to not only the texture of carbon support but also the purity of activated carbon. The activities of a series of the carbon-supported barium-promoted Ru catalysts for ammonia synthesis were measured at 425 ℃, 10.0 MPa and 10 000 h-1. The result shows that the same raw material activated carbon, with a high purity, high surface area, large pore volume and reasonable pore size distribution might disperse ruthenium and promoter sufficiently, which activated carbon as support, could be used to manufacture ruthenium catalyst with a high activity for ammonia synthesis. The different raw material activated carbon as the support would greatly influence the catalytic properties of the ruthenium catalyst for ammonia synthesis. For example, with coconut shell carbon(AC1) as the support, the ammonia concentration in the effluent was 13.17% over 4%Ru-BaO/AC1 catalyst, while with the desulfurized coal carbon(AC10) as the support, that in the effluent was only 1.37% over 4%Ru-BaO/AC10 catalyst.

  9. Removal of Trace Pharmaceuticals from Water using coagulation and powdered activated carbon as pretreatment to ultrafiltration membrane system.

    Sheng, Chenguang; Nnanna, A G Agwu; Liu, Yanghe; Vargo, John D

    2016-04-15

    In this study, the efficacy of water treatment technologies: ultra-filtration (UF), powdered activated carbon (PAC), coagulation (COA) and a combination of these technologies (PAC/UF and COA/UF) to remove target pharmaceuticals (Acetaminophen, Bezafibrate, Caffeine, Carbamazepine, Cotinine, Diclofenac, Gemfibrozil, Ibuprofen, Metoprolol, Naproxen, Sulfadimethoxine, Sulfamethazine, Sulfamethoxazole, Sulfathiazole, Triclosan and Trimethoprim) was investigated. Samples of wastewater from municipal WWTPs were analyzed using direct aqueous injection High Performance Liquid Chromatography with Tandem Quadrupole Mass Spectrometric (LC/MS/MS) detection. On concentration basis, results showed an average removal efficiency of 29%, 50%, and 7%, respectively, for the UF, PAC dosage of 50ppm, and COA dosage of 10ppm. When PAC dosage of 100ppm was used as pretreatment to the combined PAC and UF in-line membrane system, a 90.3% removal efficiency was achieved. The removal efficiency of UF in tandem with COA was 33%, an increase of 4% compared with the single UF treatment. The adsorption effect of PAC combined with the physical separation process of UF revealed the best treatment strategy for removing pharmaceutical contaminant from water. PMID:26867086

  10. Particle filtration in consolidated granular systems

    Grain-packing algorithms are used to model the mechanical trapping of dilute suspensions of particles by consolidated granular media. We study the distribution of filtrate particles, the formation of a damage zone (internal filter cake), and the transport properties of the host--filter-cake composite. At the early stages of filtration, our simulations suggest simple relationships between the structure of the internal filter cake and the characteristics of the underlying host matrix. These relationships are then used to describe the dynamics of the filtration process. Depending on the grain size and porosity of the host matrix, calculated filtration rates may either be greater than (spurt loss) or less than (due to internal clogging) those predicted by standard surface-filtration models

  11. Promoting direct interspecies electron transfer with activated carbon

    Liu, Fanghua; Rotaru, Amelia-Elena; Shrestha, Pravin M.;

    2012-01-01

    Granular activated carbon (GAC) is added to methanogenic digesters to enhance conversion of wastes to methane, but the mechanism(s) for GAC’s stimulatory effect are poorly understood. GAC has high electrical conductivity and thus it was hypothesized that one mechanism for GAC stimulation of...... methanogenesis might be to facilitate direct interspecies electron transfer (DIET) between bacteria and methanogens. Metabolism was substantially accelerated when GAC was added to co-cultures of Geobacter metallireducens and Geobacter sulfurreducens grown under conditions previously shown to require DIET. Cells...... were attached to GAC, but did not aggregate as they do when making biological electrical connections between cells. Studies with a series of gene deletion mutants eliminated the possibility that GAC promoted electron exchange via interspecies hydrogen or formate transfer and demonstrated that DIET in...

  12. Uranium Adsorption on Granular Activated Carbon – Batch Testing

    Parker, Kent E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Golovich, Elizabeth C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wellman, Dawn M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-09-01

    The uranium adsorption performance of two activated carbon samples (Tusaar Lot B-64, Tusaar ER2-189A) was tested using unadjusted source water from well 299-W19-36. These batch tests support ongoing performance optimization efforts to use the best material for uranium treatment in the Hanford Site 200 West Area groundwater pump-and-treat system. A linear response of uranium loading as a function of the solution-to-solid ratio was observed for both materials. Kd values ranged from ~380,000 to >1,900,000 ml/g for the B-64 material and ~200,000 to >1,900,000 ml/g for the ER2-189A material. Uranium loading values ranged from 10.4 to 41.6 μg/g for the two Tusaar materials.

  13. Improved Isotherm Data for Adsorption of Methane on Activated Carbons

    Loh, Wai Soong

    2010-08-12

    This article presents the adsorption isotherms of methane onto two different types of activated carbons, namely, Maxsorb III and ACF (A-20) at temperatures from (5 to 75) °C and pressures up to 2.5 MPa. The volumetric technique has been employed to measure the adsorption isotherms. The experimental results presented herein demonstrate the improved accuracy of the uptake values compared with previous measurement techniques for similar adsorbate-adsorbent combinations. The results are analyzed with various adsorption isotherm models. The heat of adsorption, which is concentration and temperature dependent, has been calculated from the measured isotherm data. Henry\\'s law coefficients for these adsorbent-methane pairs are also evaluated at various temperatures. © 2010 American Chemical Society.

  14. Magnetite decorated activated carbon composites for water purification

    Barala, Sunil Kumar; Arora, Manju; Saini, Parveen

    2013-06-01

    Activated carbon decorated with magnetite (ACMG) nanoparticles composites have been prepared by facile method via impregnation of AC with stable dispersion of superparamagnetic MG nanoparticles followed by drying. These composites exhibit both magnetic and porosity behavior which can be easily optimized by controlling the weight ratio of two phases. The structural, magnetic, thermal and morphological properties of these as synthesized ACMG samples were characterized by powder XRD, FTIR, VSM and SEM techniques. The ACMG powder has been used for water purification having methylene blue (MB) dye as an impurity. The nanoporosity of these composites allow rapid adsorption of MB and their magnetic behavior helps in single step separation of MB adsorbed ACMG particles by the application of external magnetic field.

  15. Ozonation of Cephalexin Antibiotic Using Granular Activated Carbon in a Circulating Reactor

    A circulating reactor was used to decompose cephalexin during catalytic ozonation. The effect of ozone supply and granular activated carbon (GAC) catalyst was investigated for removal of CEX and COD. The regeneration of exhausted activated carbon was investigated during in-situ ozonation. According to results, ozone supply appeared as the most influencing variable followed by dosage of granular activated carbon. The BET surface area, thermogravimetric analysis (TGA) and temperature programmed desorption (TPD) curves indicated that solid phase regeneration of activated carbon using ozone gas followed by mild thermal decomposition was very effective. The adsorption capacity of regenerated activated carbon was slightly lower than virgin activated carbon. The overall study revealed that catalytic ozonation was effective in removing cephalexin from solution and the method can be applied for in-situ ozonation processes. (author)

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

    Zhi, Yue; Liu, Jinxia

    2016-02-01

    The objective of the research was to examine the effect of increasing carbon surface basicity on uptake of perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) by activated carbon. Granular activated carbons made from coal, coconut shell, wood, and phenolic-polymer-based activated carbon fibers were modified through high-temperature and ammonia gas treatments to facilitate systematical evaluation of the impact of basicity of different origins. Comparison of adsorption isotherms and adsorption distribution coefficients showed that the ammonia gas treatment was more effective than the high-temperature treatment in enhancing surface basicity. The resultant higher point of zero charges and total basicity (measured by total HCl uptake) correlated with improved adsorption affinity for PFOS and PFOA. The effectiveness of surface modification to enhance adsorption varied with carbon raw material. Wood-based carbons and activated carbon fibers showed enhancement by one to three orders of magnitudes while other materials could experience reduction in adsorption towards either PFOS or PFOA. PMID:26469934

  17. Measurement of the activity coefficient of carbon in steels in liquid sodium

    In sodium cooled fast reactors carbon is both a carbon impurity and element of structural materials. Carbon transfert through liquid sodium can produce carburization or decarburization of structural materials. Carbon content in sodium is determined with thin foils of austenitic alloys, when equilibrium is reached thermodynamic activity of carbon in sodium is deduced from carbon activity in alloys. Studied alloys are FeMn 20%, FeNi 30%, Z2CN 18-10 and Z3CND17-13. Carbon activity of alloys in sodium was between 5.10-3 and 10-1 at 600 and 6500C. Calibration was obtained with the alloys FeNi 30% in gaseous mixtures He-CO-CO2 of known activity

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

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

    2016-08-01

    In this study, TiO2 powder was used as the additive to directly blend with raw bituminous coal and coking coal for preparing modified activated carbon (Ti/AC) by one-step carbonization-activation method. The Ti/AC samples were prepared through blending with different ratios of TiO2 (0-12 wt%) and their desulphurization performance was evaluated. The results show that the desulphurization activity of all Ti/AC samples was higher than that of the blank one, and the highest breakthrough sulphur capacity was obtained at 200.55 mg/g C when the blending ratio of TiO2 was 6 wt%. The Brunauer-Emmett-Temer results show that the micropores were dominant in the Ti/AC samples, and their textual properties did not change evidently compared with the blank one. The X-ray photoelectron spectroscopy results show that the loaded TiO2 could influence the relative content of surface functional groups, with slightly higher content of π-π* transitions groups on the Ti/AC samples, and the relative contents of C=O and π-π* transitions groups decreased evidently after the desulphurization process. The X-ray diffraction results show that the anatase TiO2 and rutile TiO2 co-existed on the surface of the Ti/AC samples. After the desulphurization process, TiO2 phases did not change and Ti(SO4)2 was not observed on the Ti/AC samples, while sulphate was the main desulphurization product. It can be assumed that SO2 could be catalytically oxidized into SO3 by TiO2 indirectly, rather than TiO2 directly reacted with SO2 to Ti(SO4)2. PMID:26695433

  19. Complete reaction mechanisms of mercury oxidation on halogenated activated carbon.

    Rungnim, Chompoonut; Promarak, Vinich; Hannongbua, Supa; Kungwan, Nawee; Namuangruk, Supawadee

    2016-06-01

    The reaction mechanisms of mercury (Hg) adsorption and oxidation on halogenated activated carbon (AC) have been completely studied for the first time using density functional theory (DFT) method. Two different halogenated AC models, namely X-AC and X-AC-X (X=Cl, Br, I), were adopted. The results revealed that HgX is found to be stable-state on the AC edge since its further desorption from the AC as HgX, or further oxidation to HgX2, are energetically unfavorable. Remarkably, the halide type does not significantly affect the Hg adsorption energy but it strongly affects the activation energy barrier of HgX formation, which obviously increases in the order HgIelimination significantly decreases as I-AC>Br-AC>Cl-AC. Thus, the study of the complete reaction mechanism is essential because the adsorption energy can not be used as a guideline for the rational material design in the halide impregnated AC systems. The activation energy is an important descriptor for the predictions of sorbent reactivity to the Hg oxidation process. PMID:26943019

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

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

    2013-10-15

    Multi-walled carbon nanotubes (MWCNTs), nano-graphene platelets (NGPs), and superfine powdered activated carbon (S-PAC) were comparatively evaluated for their applicability as adsorptive coatings on microfiltration membranes. The objective was to determine which materials were capable of contaminant removal while causing minimal flux reduction. Methylene blue and atrazine were the model contaminants. When applied as membrane coatings, MWCNTs had minimal retention capabilities for the model contaminants, and S-PAC had the fastest removal. The membrane coating approach was also compared with a stirred vessel configuration, in which the adsorbent was added to a stirred flask preceding the membrane cell. Direct application of the adsorbent to the membrane constituted a greater initial reduction in permeate concentrations of the model contaminants than with the stirred flask setup. All adsorbents except S-PAC showed flux reductions less than 5% after application as thin-layer membrane coatings, and flux recovery after membrane backwashing was greater than 90% for all materials and masses tested. PMID:23911830

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

    Szlachta, M; Wójtowicz, P

    2013-01-01

    This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m(2)/g, MWCNTs 358 m(2)/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal. PMID:24292474

  2. Adsorption capacities of activated carbons for geosmin and 2-methylisoborneol vary with activated carbon particle size: Effects of adsorbent and adsorbate characteristics.

    Matsui, Yoshihiko; Nakao, Soichi; Sakamoto, Asuka; Taniguchi, Takuma; Pan, Long; Matsushita, Taku; Shirasaki, Nobutaka

    2015-11-15

    The adsorption capacities of nine activated carbons for geosmin and 2-methylisoborneol (MIB) were evaluated. For some carbons, adsorption capacity substantially increased when carbon particle diameter was decreased from a few tens of micrometers to a few micrometers, whereas for other carbons, the increase of adsorption capacity was small for MIB and moderate for geosmin. An increase of adsorption capacity was observed for other hydrophobic adsorbates besides geosmin and MIB, but not for hydrophilic adsorbates. The parameter values of a shell adsorption model describing the increase of adsorption capacity were negatively correlated with the oxygen content of the carbon among other characteristics. Low oxygen content indicated low hydrophilicity. The increase of adsorption capacity was related to the hydrophobic properties of both adsorbates and activated carbons. For adsorptive removal of hydrophobic micropollutants such as geosmin, it is therefore recommended that less-hydrophilic activated carbons, such as coconut-shell-based carbons, be microground to a particle diameter of a few micrometers to enhance their equilibrium adsorption capacity. In contrast, adsorption by hydrophilic carbons or adsorption of hydrophilic adsorbates occur in the inner pores, and therefore adsorption capacity is unchanged by particle size reduction. PMID:26302219

  3. A gaseous measurement system for carbon-14 dioxide and carbon-14 methane: An analytical methodology to be applied in the evaluation of the carbon-14 dioxide and carbon-14 methane produced via microbial activity in volcanic tuff

    The objectives of this study were to develop a gaseous measurement system for the carbon-14 dioxide and carbon-14 methane produced via microbial activity or geochemical action on leachate in tuff; to determine the trapping efficiency of the system for carbon-14 dioxide; to determine the trapping efficiency of the system for carbon-14 methane; to apply the experimentally determined factors regarding the system's trapping efficiency for carbon-14 dioxide and carbon-14 methane to a trapping algorithm to determine the activity of the carbon-14 dioxide and carbon-14 methane in a mixed sample; to determine the minimum detectable activity of the measurement process in picocuries per liter; and to determine the lower limit or detection of the measurement process in counts per minute

  4. Use of grape must as a binder to obtain activated carbon briquettes

    A. C. Deiana; D. L. Granados; L. M. Petkovic; M. F. Sardella; H. S. Silva

    2004-01-01

    The results of studies on briquetting activated-carbon-based adsorbent materials, prepared from raw materials from the region of Cuyo, Argentina, are reported in this article. Several steps were carried out to obtain activated-carbon briquettes from Eucalyptus camaldulensis Dehn wood. These steps included carbonization of wood to obtain char; blending of char and a novel binder, i.e., grape must; formation of cylinder-like briquettes by pressure; and activation of the resulting material. The ...

  5. Evaluation of activated carbon processes for removing trihalomethane precursors from a surface water impoundment

    Lavinder, Steven Robert

    1987-01-01

    A pilot plant study was conducted in Newport News, Virginia to investigate the effectiveness of powdered activated carbon [PAC] and granular activated carbon [GAC], with and without preoxidation, for reducing trihalomethane [THM] precursor concentrations in Harwood's Mill Reservoir water. Preoxidation with ozone followed by GAC is referred to as the "biological activated carbonâ [BAC] process. This study showed that the GAC and BAC processes obtained the same level of organic...

  6. Advanced wastewater treatment by nanofiltration and activated carbon for high quality water reuse

    Kazner, Christian

    2012-01-01

    Hybrid processes combining activated carbon and nanofiltration have been studied to identify the optimum solution for advanced wastewater treatment in high quality water reclamation and reuse. With a focus on the removal of bulk and trace organic compounds the investigation identified three promising process combinations, namely powdered activated carbon followed by nanofiltration (PAC/NF), granular activated carbon followed by nanofiltration (GAC/NF) and nanofiltration followed by granular a...

  7. Production and characterization of activated carbon from indigenous coal (lakhra coal)

    In the present study, indigenous coal has been exploited for the preparation of activated carbon by physical. activation and characterization of if was done by using available techniques. Physical activation involved two steps; Carbonization and CO; activation. For different temperatures, carbonization was carried out for 4 hours in an oven and it was observed that percent yield and iodine number was maximum at 600 degree C. The carbonized material of 600 C was activated at different intervals of time and different temperatures for constant flow of CO/sub 2/; (activating gas). The optimum temperature and time for CO/sub 2/; activation was observed to be 750 C and 3 hours respectively, which gave lower percent yield of active carbon but of higher iodine number and methylene blue values. (author)

  8. Optimization of activated carbon from sewage sludge using response surface methodology

    Wastewater sludge cake was used to prepare activated carbon using physical activation method. The effects of three preparation variables; the activation temperature, activation time and carbon dioxide gas flow rate on chemical oxygen demand (COD) and ammonia removal from leachate solutions were investigated. Based on the central composite design (CCD), two quadratic models were developed to correlate the preparation variables to the COD and ammonia removal. From the analysis of variance (ANOVA), the significant factors on each experimental design response were identified. The optimum activated carbon prepared from wastewater sludge cake was obtained by using activation temperature of 510 degree Celsius, activation time of 30 min and carbon dioxide flow rate of 500 ml/ min. The optimum activated carbon showed COD and ammonia removal of 26 and 13 %, respectively. (author)

  9. Enhancing the capacitances of electric double layer capacitors based on carbon nanotube electrodes by carbon dioxide activation and acid oxidization

    2010-01-01

    Polarizable electrodes of electric double layer capacitors(EDLCs) were made from carbon nanotubes(CNTs).Effect of carbon dioxide activation together with acid oxidation for the electrodes on the characteristics and performances of electrodes and EDLCs was studied.Carbon dioxide activation changed the microstructure of the electrodes,increased the effective surface area of CNTs and optimized the distribution of apertures of the electrodes.Acid oxidization modified the surface characteristics of CNTs.Based on the polarizable electrodes treated by carbon dioxide activation and acid oxidization,the performances of EDLCs were greatly enhanced.The specific capacitance of the electrodes with organic electrolyte was increased from 21.8 F/g to 60.4 F/g.

  10. Carbon nanohorns allow acceleration of osteoblast differentiation via macrophage activation

    Hirata, Eri; Miyako, Eijiro; Hanagata, Nobutaka; Ushijima, Natsumi; Sakaguchi, Norihito; Russier, Julie; Yudasaka, Masako; Iijima, Sumio; Bianco, Alberto; Yokoyama, Atsuro

    2016-07-01

    Carbon nanohorns (CNHs), formed by a rolled graphene structure and terminating in a cone, are promising nanomaterials for the development of a variety of biological applications. Here we demonstrate that alkaline phosphatase activity is dramatically increased by coculture of human monocyte derived macrophages (hMDMs) and human mesenchymal stem cells (hMSCs) in the presence of CNHs. CNHs were mainly localized in the lysosome of macrophages more than in hMSCs during coculturing. At the same time, the amount of Oncostatin M (OSM) in the supernatant was also increased during incubation with CNHs. Oncostatin M (OSM) from activated macrophage has been reported to induce osteoblast differentiation and matrix mineralization through STAT3. These results suggest that the macrophages engulfed CNHs and accelerated the differentiation of mesenchymal stem cells into the osteoblast via OSM release. We expect that the proof-of-concept on the osteoblast differentiation capacity by CNHs will allow future studies focused on CNHs as ideal therapeutic materials for bone regeneration.Carbon nanohorns (CNHs), formed by a rolled graphene structure and terminating in a cone, are promising nanomaterials for the development of a variety of biological applications. Here we demonstrate that alkaline phosphatase activity is dramatically increased by coculture of human monocyte derived macrophages (hMDMs) and human mesenchymal stem cells (hMSCs) in the presence of CNHs. CNHs were mainly localized in the lysosome of macrophages more than in hMSCs during coculturing. At the same time, the amount of Oncostatin M (OSM) in the supernatant was also increased during incubation with CNHs. Oncostatin M (OSM) from activated macrophage has been reported to induce osteoblast differentiation and matrix mineralization through STAT3. These results suggest that the macrophages engulfed CNHs and accelerated the differentiation of mesenchymal stem cells into the osteoblast via OSM release. We expect that the

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

    Purpose: To investigate the behavior of a Monte Carlo simulation code with low levels of activity (∼1,000Bq). Such activity levels are expected from phantoms and patients activated via a proton therapy beam. Methods: Three different ranges for a therapeutic proton radiation beam were examined in a Monte Carlo simulation code: 13.5, 17.0 and 21.0cm. For each range, the decay of an equivalent length11C source and additional sources of length plus or minus one cm was studied in a benchmark PET simulation for activities of 1000, 2000 and 3000Bq. The ranges were chosen to coincide with a previous activation study, and the activities were chosen to coincide with the approximate level of isotope creation expected in a phantom or patient irradiated by a therapeutic proton beam. The GATE 7.0 simulation was completed on a cluster node, running Scientific Linux Carbon 6 (Red Hat©). The resulting Monte Carlo data were investigated with the ROOT (CERN) analysis tool. The half-life of11C was extracted via a histogram fit to the number of simulated PET events vs. time. Results: The average slope of the deviation of the extracted carbon half life from the expected/nominal value vs. activity showed a generally positive value. This was unexpected, as the deviation should, in principal, decrease with increased activity and lower statistical uncertainty. Conclusion: For activity levels on the order of 1,000Bq, the behavior of a benchmark PET test was somewhat unexpected. It is important to be aware of the limitations of low activity PET images, and low activity Monte Carlo simulations. This work was funded in part by the Philips corporation

  12. Adsorption of organic compounds onto activated carbons from recycled vegetables biomass.

    Mameli, Anna; Cincotti, Alberto; Lai, Nicola; Crisafulli, Carmelo; Sciré, Salvatore; Cao, Giacomo

    2004-01-01

    The removal of organic species from aqueous solution by activated carbons is investigated. The latter ones are prepared from olive husks and almond shells. A wide range of surface area values are obtained varying temperature and duration of both carbonization and activation steps. The adsorption isotherm of phenol, catechol and 2,6-dichlorophenol involving the activated carbons prepared are obtained at 25 degrees C. The corresponding behavior is quantitatively correlated using classical isotherm, whose parameters are estimated by fitting the equilibrium data. A two component isotherm (phenol/2,6-dichlorophenol) is determined in order to test activated carbon behavior during competitive adsorption. PMID:15347202

  13. Enhanced Activated Carbon Cathode Performance for Microbial Fuel Cell by Blending Carbon Black

    Zhang, Xiaoyuan

    2014-02-04

    Activated carbon (AC) is a useful and environmentally sustainable catalyst for oxygen reduction in air-cathode microbial fuel cells (MFCs), but there is great interest in improving its performance and longevity. To enhance the performance of AC cathodes, carbon black (CB) was added into AC at CB:AC ratios of 0, 2, 5, 10, and 15 wt % to increase electrical conductivity and facilitate electron transfer. AC cathodes were then evaluated in both MFCs and electrochemical cells and compared to reactors with cathodes made with Pt. Maximum power densities of MFCs were increased by 9-16% with CB compared to the plain AC in the first week. The optimal CB:AC ratio was 10% based on both MFC polarization tests and three electrode electrochemical tests. The maximum power density of the 10% CB cathode was initially 1560 ± 40 mW/m2 and decreased by only 7% after 5 months of operation compared to a 61% decrease for the control (Pt catalyst, 570 ± 30 mW/m2 after 5 months). The catalytic activities of Pt and AC (plain or with 10% CB) were further examined in rotating disk electrode (RDE) tests that minimized mass transfer limitations. The RDE tests showed that the limiting current of the AC with 10% CB was improved by up to 21% primarily due to a decrease in charge transfer resistance (25%). These results show that blending CB in AC is a simple and effective strategy to enhance AC cathode performance in MFCs and that further improvement in performance could be obtained by reducing mass transfer limitations. © 2014 American Chemical Society.

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

    Md.Zahangir ALAM; Suleyman A.MUYIBI; Mariatul F.MANSOR; Radziah WAHID

    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℃ and physical activation at 150℃ (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℃ 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℃. It was observed that the adsorption capacity was higher at lower values of pH (2-3) and higher value of initial concentration of phenol (200-300 mg/L). The equilibrium data fitted better with the Freundlich adsorption isotherm compared to the Langmuir. Kinetic studies of phenol adsorption onto activated carbons were also studied to evaluate the adsorption rate. The estimated cost for production of activated carbon from EFB was shown in lower price (USD 0.50/kg of AC) compared the activated carbon from other sources and processes.

  15. Highly porous activated carbons from resource-recovered Leucaena leucocephala wood as capacitive deionization electrodes.

    Hou, Chia-Hung; Liu, Nei-Ling; Hsi, Hsing-Cheng

    2015-12-01

    Highly porous activated carbons were resource-recovered from Leucaena leucocephala (Lam.) de Wit. wood through combined chemical and physical activation (i.e., KOH etching followed by CO2 activation). This invasive species, which has severely damaged the ecological economics of Taiwan, was used as the precursor for producing high-quality carbonaceous electrodes for capacitive deionization (CDI). Carbonization and activation conditions strongly influenced the structure of chars and activated carbons. The total surface area and pore volume of activated carbons increased with increasing KOH/char ratio and activation time. Overgasification induced a substantial amount of mesopores in the activated carbons. In addition, the electrochemical properties and CDI electrosorptive performance of the activated carbons were evaluated; cyclic voltammetry and galvanostatic charge/discharge measurements revealed a typical capacitive behavior and electrical double layer formation, confirming ion electrosorption in the porous structure. The activated-carbon electrode, which possessed high surface area and both mesopores and micropores, exhibited improved capacitor characteristics and high electrosorptive performance. Highly porous activated carbons derived from waste L. leucocephala were demonstrated to be suitable CDI electrode materials. PMID:26135977

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

    Zhu, Tingting; Dittrich, Maria

    2016-01-01

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

  17. Carbonate precipitation through microbial activities in natural environment, and their potential in biotechnology: a review

    Tingting eZhu

    2016-01-01

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

  18. EFFICACY OF FILTRATION PROCESSES TO OBTAIN WATER CLARITY AT K EAST SPENT NUCLEAR FUEL (SNF) BASIN

    DUNCAN JB

    2006-09-28

    The objective is to provide water clarity to the K East Basin via filtration processes. Several activities are planned that will challenge not only the capacity of the existing ion exchange modules to perform as needed but also the current filtration system to maintain water clarity. Among the planned activities are containerization of sludge, removal of debris, and hydrolasing the basin walls to remove contamination.

  19. EFFICACY OF FILTRATION PROCESSES TO OBTAIN WATER CLARITY AT K EAST SPENT NUCLEAR FUEL (SNF) BASIN

    The objective is to provide water clarity to the K East Basin via filtration processes. Several activities are planned that will challenge not only the capacity of the existing ion exchange modules to perform as needed but also the current filtration system to maintain water clarity. Among the planned activities are containerization of sludge, removal of debris, and hydrolasing the basin walls to remove contamination

  20. 金属盐改性活性炭吸附去除水中苯酚实验研究%Experimental study on adsorption performance of phenol in water with activated carbon by metal salts modified

    杨英; 孟红旗; 李素敏

    2012-01-01

    Activated carbon modified by Metal salts has broad application prospects in water purification. The modified activated carbons from five salts( Al^3+ , H ^+ ,Zn^2+ , Cu^2+ , Mn^7+ ) were respectively prepared using the impregnation method, and the adsorption performance of phenol solution by a filtration process was investigated with different modified activated carbon. The results showed that the adsorption performance on modified acti- vated carbons by these different salts gradually decreased in the direction: Al^3+ 〉 H ^+ 〉Zn^2+ 〉 Cu^2+〉 Mn^7+ . The filter bed of modified activated carbons had a stronger resistance impact on phenol solution. In a lower filtration rate, the purification capacity of modified activated carbon by aluminum salts achieved more than 99% in dealing with low concentrations of phenol solution, and the effluent concentration was lower than 1 mg/L. Overall. The effect of this kind activated carbon was superior to the other kind by hydrochloric acids. Therefore, in the depth of water treatment, aluminum salts can be used as one of the main direction of the ac- tivated carbon modified.%金属盐改性活性炭在净水处理中具有广阔的应用前景.利用浸渍法制备了5种(Al3+,H+,Zn2+,Cu2+,Mn7+)改性活性炭,用过滤手段对改性活性炭吸附去除苯酚的性能进行了研究.结果表明,各种改性活性炭过滤去除苯酚性能的高低顺序为:Al3+〉H+〉Zn2+〉CK〉Cu2+〉Mn7+;活性炭滤柱对苯酚原水具有较强的耐冲击性能,在较低滤速下,铝盐改性活性炭滤柱对中低质量浓度苯酚水的净化能力达99%以上,出水质量浓度低于1 mg/L,整体上优于盐酸活化炭滤柱.在净水深度处理中,铝盐可作为活性炭改性的主要方向之一.

  1. Impact of mooring activities on carbon stocks in seagrass meadows

    Serrano, O.

    2016-03-16

    Boating activities are one of the causes that threaten seagrass meadows and the ecosystem services they provide. Mechanical destruction of seagrass habitats may also trigger the erosion of sedimentary organic carbon (Corg) stocks, which may contribute to increasing atmospheric CO2. This study presents the first estimates of loss of Corg stocks in seagrass meadows due to mooring activities in Rottnest Island, Western Australia. Sediment cores were sampled from seagrass meadows and from bare but previously vegetated sediments underneath moorings. The Corg stores have been compromised by the mooring deployment from 1930s onwards, which involved both the erosion of existing sedimentary Corg stores and the lack of further accumulation of Corg. On average, undisturbed meadows had accumulated ~6.4 Kg Corg m−2 in the upper 50 cm-thick deposits at a rate of 34 g Corg m−2 yr−1. The comparison of Corg stores between meadows and mooring scars allows us to estimate a loss of 4.8 kg Corg m−2 in the 50 cm-thick deposits accumulated over ca. 200 yr as a result of mooring deployments. These results provide key data for the implementation of Corg storage credit offset policies to avoid the conversion of seagrass ecosystems and contribute to their preservation.

  2. Conversion of some fruit stones and shells into activated carbons

    The pyrolysis of certain biomass waste (stones of date, apricot, peach and olive as well as shells of walnut and coconut) was investigated to prepare activated carbons (ACs) suitable for some commercial purposes. The pyrolysis process was performed into fixed bed reactor which was designed for this purpose. The resulted char was chemically activated using NaOH and the adsorption characteristics, such as iodine number, methylene blue (MB) value, and p-nitrophenol (PNP) value were measured. The surface area of the prepared ACs were estimated from the calibration curve as between IN and BET surface area of some established ACs from the literature. The adsorption from solution method was also used to measure the specific surface area of the prepared ACs, using MB and PNP as solutes. The adsorption isotherms of the ACs from both atmospheric pyrolysis (AP) and reduced pressure pyrolysis (RPP) were determined and were found to fit the Langmuir type of isotherm. The prepared ACs show different adsorption properties and surface areas, and that AC obtained from apricot stones had the highest porosity as indicating by IN and SABET. (author)

  3. Impact of mooring activities on carbon stocks in seagrass meadows

    Serrano, O.; Ruhon, R.; Lavery, P. S.; Kendrick, G. A.; Hickey, S.; Masqué, P.; Arias-Ortiz, A.; Steven, A.; Duarte, C. M.

    2016-03-01

    Boating activities are one of the causes that threaten seagrass meadows and the ecosystem services they provide. Mechanical destruction of seagrass habitats may also trigger the erosion of sedimentary organic carbon (Corg) stocks, which may contribute to increasing atmospheric CO2. This study presents the first estimates of loss of Corg stocks in seagrass meadows due to mooring activities in Rottnest Island, Western Australia. Sediment cores were sampled from seagrass meadows and from bare but previously vegetated sediments underneath moorings. The Corg stores have been compromised by the mooring deployment from 1930s onwards, which involved both the erosion of existing sedimentary Corg stores and the lack of further accumulation of Corg. On average, undisturbed meadows had accumulated ~6.4 Kg Corg m‑2 in the upper 50 cm-thick deposits at a rate of 34 g Corg m‑2 yr‑1. The comparison of Corg stores between meadows and mooring scars allows us to estimate a loss of 4.8 kg Corg m‑2 in the 50 cm-thick deposits accumulated over ca. 200 yr as a result of mooring deployments. These results provide key data for the implementation of Corg storage credit offset policies to avoid the conversion of seagrass ecosystems and contribute to their preservation.

  4. Carbon Mineralization in Acidic, Xeric Forest Soils: Induction of New Activities

    Tate, Robert L.

    1985-01-01

    Carbon mineralization was examined in Lakehurst and Atsion sands collected from the New Jersey Pinelands and in Pahokee muck from the Everglades Agricultural Area. Objectives were (i) to estimate the carbon mineralization capacities of acidic, xeric Pinelands soils in the absence of exogenously supplied carbon substrate (nonamended carbon mineralization rate) and to compare these activities with those of agriculturally developed pahokee muck, and (ii) to measure the capacity for increased car...

  5. Investigation of physiologically active products obtained from carbon-ion irradiated actinomycetes

    Charged particles such as carbon-ions are superior to X-rays or gamma-rays in the physical and biological characteristics. The propose research project is aimed to provide new insights on antibiotic development. Carbon-ion exposure reduced cell growth. Product(s) from carbon-ion irradiated microorganera suppressed growth of human leukemia cells. We suggested that carbon-ion irradiated actinomycetes produce antitumor active product(s) for leukemia cells. (author)

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

    Zhu, Tingting; Dittrich, Maria

    2016-01-01

    Calcium carbonate represents a large portion of carbon reservoir and is used commercially for a variety of applications. Microbial carbonate precipitation, a by-product of microbial activities, plays an important metal coprecipitation and cementation role in natural systems. This natural process occurring in various geological settings can be mimicked and used for a number of biotechnologies, such as metal remediation, carbon sequestration, enhanced oil recovery, and construction restoration....

  7. Impact of carbon on the surface and activity of silica-carbon supported copper catalysts for reduction of nitrogen oxides

    Spassova, I.; Stoeva, N.; Nickolov, R.; Atanasova, G.; Khristova, M.

    2016-04-01

    Composite catalysts, prepared by one or more active components supported on a support are of interest because of the possible interaction between the catalytic components and the support materials. The supports of combined hydrophilic-hydrophobic type may influence how these materials maintain an active phase and as a result a possible cooperation between active components and the support material could occur and affects the catalytic behavior. Silica-carbon nanocomposites were prepared by sol-gel, using different in specific surface areas and porous texture carbon materials. Catalysts were obtained after copper deposition on these composites. The nanocomposites and the catalysts were characterized by nitrogen adsorption, TG, XRD, TEM- HRTEM, H2-TPR, and XPS. The nature of the carbon predetermines the composite's texture. The IEPs of carbon materials and silica is a force of composites formation and determines the respective distribution of the silica and carbon components on the surface of the composites. Copper deposition over the investigated silica-carbon composites leads to formation of active phases in which copper is in different oxidation states. The reduction of NO with CO proceeds by different paths on different catalysts due to the textural differences of the composites, maintaining different surface composition and oxidation states of copper.

  8. A cost-effective and versatile technology for regenerating activated carbon

    McLaughlin, H. [Waste Min, Inc., Croton, MA (United States)

    1996-12-31

    Adsorption by activated carbon is a mainstream technology for the removal of soluble chemicals from waters and wastewaters, as well as for the removal of organics from vapor streams. Activated carbon basically acts like a sponge - accumulating the chemical species removed from the liquid or vapor stream. When the capacity of the carbon is reached, the spent carbon must be replaced or regenerated to restore its ability to adsorb. The current commercial regeneration options for spent carbon have significant shortcomings. Regeneration by steaming or low temperature heating removes low boiling organic compounds from vapor-phase carbon, but is not efficient removing less volatile compounds and does not regenerate liquid-phase activated carbons. High temperature thermal regeneration methods are expensive to build and operate, have high energy requirements, destroy the adsorbed compounds, and gradually destroy the carbon itself. An alternative technology that avoids the shortcomings of current methods is regeneration of spent activated carbon by extraction with organic solvents. The process uses an organic solvent to dissolve adsorbed material out of the internal pores of the activated carbon. Subsequently, the residual solvent is removed, typically by steaming, then the solvent is recovered and recycled. Cost-wise, solvent regeneration of activated carbon is substantially less expensive than thermal methods. The solvent regeneration technology works for virtually all adsorption applications where thermal regeneration is currently utilized. Capacity-wise, solvent regeneration restores 70% to 90% of the adsorption capacity of virgin activated carbon - while recovering the adsorbates intact and without deteriorating the activated carbon. 3 refs., 2 figs.

  9. Influence of KOH activation techniques on pore structure and electrochemical property of carbon electrode materials

    LI Jing; LI Jie; LAI Yan-qing; SONG Hai-sheng; ZHANG Zhi-an; LIU Ye-xiang

    2006-01-01

    Taking the selection of coal-tar pitch as precursor and KOH as activated agent, the activated carbon electrode material was fabricated for supercapacitor. The surface area and the pore structure of activated carbon were analyzed by Nitro adsorption method. The electrochemical properties of the activated carbons were determined using two-electrode capacitors in 6 mol/L KOH aqueous electrolytes. The influences of activated temperature and mass ratio ofKOH to C on the pore structure and electrochemical property of porous activated carbon were investigated in detail. The reasons for the changes of pore structure and electrochemical performance of activated carbon prepared under different conditions were also discussed theoretically. The results indicate that the maximum specific capacitance of 240 F/g can be obtained in alkaline medium, and the surface area, the pore structure and the specific capacitance of activated carbon depend on the treatment methods; the capacitance variation of activated carbon cannot be interpreted only by the change of surface area and pore structure, the lattice order and the electrolyte wetting effect of the activated carbon should also be taken into account.

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

    Al-Rahbi, Amal S; Williams, Paul T

    2016-03-01

    Waste tyres were pyrolysed in a bench scale reactor and the product chars were chemically activated with alkali chemical agents, KOH, K2CO3, NaOH and Na2CO3 to produce waste tyre derived activated carbons. The activated carbon products were then examined in terms of their ability to adsorb NOx (NO) at low temperature (25°C) from a simulated industrial process flue gas. This study investigates the influence of surface area and porosity of the carbons produced with the different alkali chemical activating agents on NO capture from the simulated flue gas. The influence of varying the chemical activation conditions on the porous texture and corresponding NO removal from the flue gas was studied. The activated carbon sorbents were characterized in relation to BET surface area, micropore and mesopore volumes and chemical composition. The highest NO removal efficiency for the waste tyre derived activated carbons was ∼75% which was obtained with the adsorbent treated with KOH which correlated with both the highest BET surface area and largest micropore volume. In contrast, the waste tyre derived activated carbons prepared using K2CO3, NaOH and Na2CO3 alkali activating agents appeared to have little influence on NO removal from the flue gases. The results suggest problematic waste tyres, have the potential to be converted to activated carbons with NOx removal efficiency comparable with conventionally produced carbons. PMID:26856444

  11. Assessing the fate of organic micropollutants during riverbank filtration utilizing field studies and laboratory test systems

    Schmidt, C. K.; Lange, F. T.; Sacher, F.; Baus, C.; Brauch, H.-J.

    2003-04-01

    observations demonstrate, that levels of many organic micropollutants present in natural river waters can be reduced or even eliminated during aerobic and anaerobic bankfiltration. As such, the water quality is improved and subsequent treatment steps, such as granular activated carbon filtration, may be supported and simplified leading to decreased water treatment costs. Test filter experiments are a suitable tool to predict the extent of elimination of emerging organic contaminants during aerobic bankfiltration.

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

    Ifelebuegu, A.O.; Lester, J.N.; Churchley, J.; Cartmell, E. [Cranfield University, Cranfield (United Kingdom). School of Water Science

    2006-12-15

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

  13. PREPARATION OF MICROWAVE ABSORBING NICKEL-BASED ACTIVATED CARBON BY ELECTROLESS PLATING WITH PALLADIUM-FREE ACTIVATION

    Boyang Jia

    2010-08-01

    Full Text Available Nickel-based activated carbon was prepared from coconut shell activated carbon by electroless plating with palladium-free activation. The materials were characterized by scanning electron microscopy (SEM, X-ray energy dispersion spectroscopy (EDS, vibrating sample magnetometry (VSM, and vector network analyzer, respectively. The results show that the surface of the activated carbon was covered by a Ni-P coating, which was uniform, compact, and continuous and had an obvious metallic sheen. The content of P and Ni was 2.73% and 97.27% in the coating. Compared with the untreated activated carbon, the real permeability μ′ and imaginary permeability μ″ of Ni-based activated carbon became greater, whereas the real permittivity ε′ and imaginary permittivity ε″ became smaller. Also, the plated activated carbon was magnetic, making it suitable for some special applications. In general, the method reported here might be a feasible procedure to coat activated carbon with other magnetic metals, which may find application in various areas.

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

    Li, Wei; Wang, Xinying; Peng, Jinhui

    2014-01-01

    The regeneration of spent powdered activated carbons used in xylose decolourization by microwave heating was investigated. Effects of microwave power and microwave heating time on the adsorption capacity of regenerated activated carbons were evaluated. The optimum conditions obtained are as follows: microwave power 800W; microwave heating time 30min. Regenerated activated carbon in this work has high adsorption capacities for the amount of methylene blue of 16 cm3/0.1 g and the iodine number of 1000.06mg/g. The specific surface areas of fresh commercial activated carbon, spent carbon and regenerated activated carbon were calculated according to the Brunauer, Emmett and Teller method, and the pore-size distributions of these carbons were characterized by non-local density functional theory (NLDFT). The results show that the specific surface area and the total pore volume of regenerated activated carbon are 1064 m2/g and 1.181 mL/g, respectively, indicating the feasibility of regeneration of spent powdered activated carbon used in xylose decolourization by microwave heating. The results of surface fractal dimensions also confirm the results of isotherms and NLDFT. PMID:24645431

  15. Surface modification, characterization and adsorptive properties of a coconut activated carbon

    Lu, Xincheng; Jiang, Jianchun; Sun, Kang; Xie, Xinping; Hu, Yiming

    2012-08-01

    A coconut activated carbon was modified using chemical methods. Different concentration of nitric acid oxidation of the conventional sample produced samples with weakly acidic functional groups. The oxidized samples were characterized by scanning electron micrograph, nitrogen absorption-desorption, Fourier transform infra red spectroscopy, Bothem method, pH titration, adsorption capacity of sodium and formaldehyde, and the adsorption mechanism of activated carbons was investigated. The results showed that BET surface area and pore volume of activated carbons were decreased after oxidization process, while acidic functional groups were increased. The surface morphology of oxidized carbons looked clean and eroded which was caused by oxidization of nitric acid. The oxidized carbons showed high adsorption capacity of sodium and formaldehyde, and chemical properties of activated carbon played an important role in adsorption of metal ions and organic pollutants.

  16. Binder-less activated carbon electrode from gelam wood for use in supercapacitors

    IVANDINI A. TRIBIDASARI

    2013-04-01

    Full Text Available This work focused on the relation between the porous structure of activated carbon and its capacitive properties. Three types of activated carbon monoliths were used as the electrodes in a half cell electrochemical system. One monolith was produced from activated carbon and considered to be a binder-less electrode. Two others were produced from acid and high pressure steam oxidized activated carbon. The micrographs clearly indicate that three electrodes have different porous structures. Both porosity and surface area of carbons increased due to the formation of grains during oxidation. This fact specified that an acid oxidized carbon monolith will have relatively higher capacitance compared to non-oxidized and steam oxidized monoliths. Maximum capacitance values for acid, steam oxidized and non-oxidized electrodes were 27.68, 2.23 and 1.20 F g-1, respectively.

  17. A review of activated carbon technologies for reducing MSW incinerator emissions

    Though activated carbon is, by no means, a newcomer to the pollution control field, having been used as a water purifier and more recently demonstrated as a flue gas cleaner on power plants, it is now attracting considerable attention in Europe as a means to reduce further the quantity of toxic organic and metal emissions from new and existing municipal waste combustors. Since activated carbon is a potentially important future emissions control technology for MWCs in the US, particularly for removal of mercury and dioxin, this paper discusses the impetus which has motivated the experimentation with various activated carbon technologies which is now taking place, will describe how some of the activated carbon systems (e.g., post-emissions control fixed carbon bed and injection of carbon with scrubber reagent) being tested now function and where they fit in existing pollution control trains, and will present available performance data and emissions reductions actually achieved for each system

  18. Surface modification, characterization and adsorptive properties of a coconut activated carbon

    A coconut activated carbon was modified using chemical methods. Different concentration of nitric acid oxidation of the conventional sample produced samples with weakly acidic functional groups. The oxidized samples were characterized by scanning electron micrograph, nitrogen absorption-desorption, Fourier transform infra red spectroscopy, Bothem method, pH titration, adsorption capacity of sodium and formaldehyde, and the adsorption mechanism of activated carbons was investigated. The results showed that BET surface area and pore volume of activated carbons were decreased after oxidization process, while acidic functional groups were increased. The surface morphology of oxidized carbons looked clean and eroded which was caused by oxidization of nitric acid. The oxidized carbons showed high adsorption capacity of sodium and formaldehyde, and chemical properties of activated carbon played an important role in adsorption of metal ions and organic pollutants.

  19. Systematic Analysis of Carbon Dioxide Activation of Waste Tire by Factorial Design

    P.P.M. Fung; W.H-Cheung; G. McKay

    2012-01-01

    In this study, waste tire was used as raw material for the production of activated carbons through pyrolysis. 'Fire char was first produced by carbomzation at 550℃ under nitrogen. A two tactortal design was used to optimize the production of activated carbon from tire char. The effects of several factors controlling the activation process, such as temperature (.830-930℃), time (2-6h) and percentage ot carbon dioxide (70%-100%) were investigated. The production was described mathematically as a function of these three factors. First order modeling equations were developed for surface area, yield and mesopore volume. It was concluded that the yield, BET surface area and mesopore volume of activated carbon were most sensitive to activation temperature and time while percentage of carbon dioxide in the activation gas was a less significant factor.

  20. Photocatalytic Activity and Characterization of Carbon-Modified Titania for Visible-Light-Active Photodegradation of Nitrogen Oxides

    Chun-Hung Huang

    2012-01-01

    Full Text Available A variety of carbon-modified titania powders were prepared by impregnation method using a commercial available titania powder, Hombikat UV100, as matrix material while a range of alcohols from propanol to hexanol were used as precursors of carbon sources. Rising the carbon number of alcoholic precursor molecule, the modified titania showed increasing visible activities of NOx photodegradation. The catalyst modified with cyclohexanol exhibited the best activities of 62%, 62%, 59%, and 54% for the total NOx removal under UV, blue, green, and red light irradiation, respectively. The high activity with long wavelength irradiation suggested a good capability of photocatalysis in full visible light spectrum. Analysis of UV-visible spectrum indicated that carbon modification promoted visible light absorption and red shift in band gap. XPS spectroscopic analysis identified the existence of carbonate species (C=O, which increased with the increasing carbon number of precursor molecule. Photoluminescence spectra demonstrated that the carbonate species suppressed the recombination rate of electron-hole pair. As a result, a mechanism of visible-light-active photocatalyst was proposed according to the formation of carbonate species on carbon-modified TiO2.