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1

Activated carbon from pecan shell: process description and economic analysis  

Microsoft Academic Search

Granular activated carbons derived from pecan shells have been shown to adsorb a variety of metal and organic species in various processing wastewaters. Their effectiveness is equivalent to or exceeds comparable commercial carbons in this regard. The objectives of this study were to develop process flow diagrams for the large-scale production of pecan shell-based carbons derived from steam or phosphoric

Chilton Ng; Wayne E Marshall; Ramu M Rao; Rishipal R Bansode; Jacques N Losso

2003-01-01

2

ACTIVATED CARBON PROCESS FOR TREATMENT OF WASTEWATERS CONTAINING HEXAVALENT CHROMIUM  

EPA Science Inventory

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

3

Carbonation process of alkali-activated slag mortars  

Microsoft Academic Search

This study analyzes the behaviour of waterglass- or NaOH-activated slag mortars after carbonation. The effect of a superplasticizer\\u000a based on vinyl copolymer and shrinkage reducing polypropylenglycol derivative admixtures on that process was also examined.\\u000a The same tests were run on cement mortars for reference purposes. The mortars were carbonated in a chamber ensuring CO2 saturation for four and eight months,

F. Puertas; M. Palacios; T. Vázquez

2006-01-01

4

Activated Sludge with Powdered Activated Carbon Treatment of a Dyes and Pigments Processing Wastewater.  

National Technical Information Service (NTIS)

This paper discusses completed efforts in the treatment of dyes and pigments processing wastewater utilizing the activated sludge process (ASP) enhanced with powdered activated carbon (PAC). The independent variables of the study were solids retention tim...

G. M. Shaul M. W. Barnett T. W. Neiheisel K. A. Dostal

1983-01-01

5

APPRAISAL OF POWDERED ACTIVATED CARBON PROCESSES FOR MUNICIPAL WASTEWATER TREATMENT  

EPA Science Inventory

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

6

Production of activated carbons from waste tire – process design and economical analysis  

Microsoft Academic Search

The process design and economic analysis of process plants to produce activated carbons from waste tires and coal have been performed. The potential range of products from each process has been considered, namely for waste tire – pyro-gas, active carbon, carbon black and pyro-oil; for coal – pyro-gas and active carbons. Sensitivity analyses have been carried out on the main

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

2004-01-01

7

ACTIVATED SLUDGE WITH POWDERED ACTIVATED CARBON TREATMENT OF A DYES AND PIGMENTS PROCESSING WASTEWATER  

EPA Science Inventory

This paper discusses completed efforts in the treatment of dyes and pigments processing wastewater utilizing the activated sludge process (ASP) enhanced with powdered activated carbon (PAC). The independent variables of the study were solids retention time (SRT) and PAC dosage. T...

8

Concurrent Removal of Toxic Heavy Metals and Organic Substances by Activated Carbon Process from Contaminated Groundwater.  

National Technical Information Service (NTIS)

The treatability of groundwater containing both toxic heavy metals and organic substances was performed in the laboratory using synthetic solutions and activated carbon adsorption process. Two typical activated carbons, i.e., Nuchar SA (an L-type) and Fil...

C. P. Huang

1984-01-01

9

Carbon activation process for increased surface accessibility in electrochemical capacitors  

DOEpatents

A process for making carbon film or powder suitable for double capacitor electrodes having a capacitance of up to about 300 F/cm.sup.3 is disclosed. This is accomplished by treating in aqueous nitric acid for a period of about 5 to 15 minutes thin carbon films obtained by carbonizing carbon-containing polymeric material having a high degree of molecular directionality, such as polyimide film, then heating the treated carbon film in a non-oxidizing atmosphere at a non-graphitizing temperature of at least 350.degree. C. for about 20 minutes, and repeating alternately the nitric acid step and the heating step from 7 to 10 times. Capacitors made with this carbon may find uses ranging from electronic devices to electric vehicle applications.

Doughty, Daniel H. (Albuquerque, NM); Eisenmann, Erhard T. (Belpre, OH)

2001-01-01

10

Biofilm processes in biologically active carbon water purification  

Microsoft Academic Search

This review paper serves to describe the composition and activity of a biologically active carbon (BAC) biofilm used in water purification. An analysis of several physical–chemical, biochemical and microbiological methods (indicators) used to characterize the BAC biofilm's composition and activity is provided. As well, the ability of the biofilm to remove and biodegrade waterborne organic substances and pollutants will be

David R. Simpson

2008-01-01

11

ACTIVATED CARBON PROCESS FOR THE TREATMENT OF CADMIUM(II)-CONTAINING WASTEWATERS  

EPA Science Inventory

The removal of cadmium(II) from two synthetic cadmium plating wastewaters by an activated carbon adsorption process has been investigated. Among the 17 different types of activated carbon tested, it was found that the acidic activated carbons, namely Nuchar SA and Nuchar SN exhib...

12

Process for producing an activated carbon adsorbent with integral heat transfer apparatus  

NASA Technical Reports Server (NTRS)

A process for producing an integral adsorbent-heat exchanger apparatus useful in ammonia refrigerant heat pump systems. In one embodiment, the process wets an activated carbon particles-solvent mixture with a binder-solvent mixture, presses the binder wetted activated carbon mixture on a metal tube surface and thereafter pyrolyzes the mixture to form a bonded activated carbon matrix adjoined to the tube surface. The integral apparatus can be easily and inexpensively produced by the process in large quantities.

Jones, Jack A. (Inventor); Yavrouian, Andre H. (Inventor)

1996-01-01

13

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

Microsoft Academic Search

In this paper, the drinking water biotic safety of particles and bacteria attached to fines in activated carbon process was\\u000a investigated by actual treatment process and advanced treatment pilot trial with granular activated carbon. In the experiment,\\u000a the particles were detected by IBR particle calculating instrument, the activated carbon fines were counted on the basis of\\u000a the most probable number

Wei Chen; Tao Lin; Leilei Wang

2007-01-01

14

Materials performance in the wet air regeneration of spent carbon slurry from the powdered carbon - Activated sludge treatment process  

Microsoft Academic Search

The corrosion resistance of various alloys to wet air regeneration (WAR) of spent carbon slurry from the powdered carbon - activated sludge process is discussed. This process is carried out at 220 - 250°C and pressures of 800 - 1100 psig (5.5 - 7.6 MPa). Laboratory shaking autoclave corrosion test procedures used to evaluate materials under WAR conditions are described.

T. P. Oettinger; M. C. Hoffman; M. G. Fontana

1987-01-01

15

Production of activated carbon from bamboo scaffolding waste—process design, evaluation and sensitivity analysis  

Microsoft Academic Search

A feasibility study has been carried out on the preliminary process design of the production of activated carbon from the bamboo scaffolding waste based on 30tonnes of bamboo waste per day throughput. A comparison of the process economics of the stand-alone bamboo carbonization plant with a plant that is integrated into another major processing facility has been studied. The preliminary

Keith K. H. Choy; John P. Barford; Gordon McKay

2005-01-01

16

Evaluation of the Health Aspects of Activated Carbon (Charcoal) as a Food Processing Aid.  

National Technical Information Service (NTIS)

This report, by a group of qualified scientists designated the Select Committee of GRAS Substances (SCOGS), provides an independent evaluation of the safety of the health aspects of activated carbon (charcoal) as a food processing aid.

1981-01-01

17

Process for Recovering Adsorbed Gold and/or Silver Values from Activated Carbon.  

National Technical Information Service (NTIS)

The patent application provides a method for recovering gold and/or silver values which have been adsorbed onto activated carbon from a processing solution. Briefly it comprises contacting metal loaded activatedcarbon with an eluent selected from the grou...

Fischer

1975-01-01

18

DEVELOPMENT OF THE WESTVACO ACTIVATED CARBON PROCESS FOR SOX RECOVERY AS ELEMENTAL SULFUR. VOLUME I  

EPA Science Inventory

The report gives results of a demonstration (in a 20,000-cfh integral pilot plant) of an all-dry, fluidized-bed process, using activated carbon for recovering SO2 as elemental sulfur. Granular carbon was recycled continuously more than 20 times between contact with flue gas from ...

19

DEVELOPMENT OF THE WESTVACO ACTIVATED CARBON PROCESS FOR SOX RECOVERY AS ELEMENTAL SULFUR. VOLUME II. APPENDIX  

EPA Science Inventory

The report gives results of a demonstration (in a 20,000-cfh integral pilot plant) of an all-dry, fluidized-bed process, using activated carbon for recovering SO2 as elemental sulfur. Granular carbon was recycled continuously more than 20 times between contact with flue gas from ...

20

Preparation of electrochemically active lithium sulfide–carbon composites using spark-plasma-sintering process  

Microsoft Academic Search

Electrochemically active lithium sulfide–carbon (Li2S–C) composite positive electrodes, applicable for rechargeable lithium-ion batteries, were prepared using spark-plasma-sintering (SPS) process. The electrochemical tests demonstrated that the SPS-treated Li2S–C composites showed the initial charge and discharge capacities of ca. 1200 and 200mAhg?1, respectively, though Li2S has been reported to show no significant charge capacities when conventionally mixed with carbon powder. Such activation

Tomonari Takeuchi; Hikari Sakaebe; Hiroyuki Kageyama; Hiroshi Senoh; Tetsuo Sakai; Kuniaki Tatsumi

2010-01-01

21

Interactions of xanthines with activated carbon. I. Kinetics of the adsorption process  

NASA Astrophysics Data System (ADS)

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.

Navarrete Casas, R.; García Rodriguez, A.; Rey Bueno, F.; Espínola Lara, A.; Valenzuela Calahorro, C.; Navarrete Guijosa, A.

2006-06-01

22

Activated carbon from olive kernels in a two-stage process: Industrial improvement  

Microsoft Academic Search

Activated carbons have been prepared from olive kernels and their adsorptive characteristics were investigated. A two stage process of pyrolysis-activation has been tested in two scales: (a) laboratory scale pyrolysis and chemical activation with KOH and (b) pilot\\/bench scale pyrolysis and physical activation with H2O–CO2. In the second case, olive kernels were first pyrolysed at 800°C, during 45min under an

A. Zabaniotou; G. Stavropoulos; V. Skoulou

2008-01-01

23

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

PubMed

A coupling of low-temperature sulfuric acid-assisted carbonization and H3PO4 activation was employed to convert NaOH-pretreated rice husks into activated carbons with extremely high surface area (2028 m(2) g(-1)) and integrated characteristics. The influences of the activation temperature and impregnation ratio on the surface area, pore volume of activated carbons were thoroughly investigated. The morphology and surface chemistry of activated carbons were characterized using N2 sorption, FTIR, XPS, SEM, TEM, etc. The adsorption capacity of resulting carbons obtained under optimum preparation conditions was systematically evaluated using methylene blue under various simulated conditions. The adsorption process can be well described by both Langmuir isotherm model and the pseudo-second order kinetics models; and the maximum monolayer capacity of methylene blue was ca. 578 mg g(-1). PMID:23892148

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

2013-09-01

24

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

PubMed

The performances of various soil washing processes, including surfactant recovery by selective adsorption, were evaluated using a mathematical model for partitioning a target compound and surfactant in water/sorbent system. Phenanthrene was selected as a representative hazardous organic compound and Triton X-100 as a surfactant. Two activated carbons that differed in size (Darco 20-40 mesh and >100 mesh sizes) were used in adsorption experiments. The adsorption isotherms of the chemicals were used in model simulations for various washing scenarios. The optimal process conditions were suggested to minimize the dosage of activated carbon and surfactant and the number of washings. We estimated that the requirement of surfactant could be reduced to 33% of surfactant requirements (from 265 to 86.6g) with a reuse step using 9.1g activated carbon (>100 mesh) to achieve 90% removal of phenanthrene (initially 100mg kg-soil(-1)) with a water/soil ratio of 10. PMID:18384951

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

2008-12-15

25

Phenol wastewater treatment by a two-step adsorption–oxidation process on activated carbon  

Microsoft Academic Search

The interest of a two-step adsorption–oxidation process for treatment of aqueous phenolic effluents has been investigated. This process is based on the use of activated carbon as adsorbent in the first step and as oxidation catalyst in the second step, in a single bi-functional reactor. The main advantage of this process concerns the regeneration–oxidation step, for which only a small

I. Polaert; A. M. Wilhelm; H. Delmas

2002-01-01

26

Activated carbon from broiler litter: Process description and cost of production  

Microsoft Academic Search

Animal manure continues to represent a significantly large and problematic portion of the US agricultural waste generated yearly. Granular activated carbons made from pelletized poultry litter have been shown to adsorb various positively charged metal ions from laboratory-prepared solutions. The objective of this study was to develop a conceptual capital and operating cost estimate using the Superpro Designer process simulation

Isabel M. Lima; Andrew McAloon; Akwasi A. Boateng

2008-01-01

27

Process optimization for methyl ester production from waste cooking oil using activated carbon supported potassium fluoride  

Microsoft Academic Search

This paper presents the transesterification of waste cooking palm oil (WCO) using activated carbon supported potassium fluoride catalyst. A central composite rotatable design was used to optimize the effect of molar ratio of methanol to oil, reaction period, catalyst loading and reaction temperature on the transesterification process. The reactor was pressurized up to 10 bar using nitrogen gas. All the variables

B. H. Hameed; C. S. Goh; L. H. Chin

2009-01-01

28

Carbon wastewater treatment process  

NASA Technical Reports Server (NTRS)

A new powdered-carbon treatment process is being developed for the elimination of the present problems, associated with the disposal of biologically active sewage waste solids, and with water reuse. This counter-current flow process produces an activated carbon, which is obtained from the pyrolysis of the sewage solids, and utilizes this material to remove the adulterating materials from the water. Additional advantages of the process are the elimination of odors, the removal of heavy metals, and the potential for energy conservation.

Humphrey, M. F.; Simmons, G. M.; Dowler, W. L.

1974-01-01

29

Preparation of a carbon-based solid acid catalyst by sulfonating activated carbon in a chemical reduction process.  

PubMed

Sulfonated (SO(3)H-bearing) activated carbon (AC-SO(3)H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO(3)H density of 0.64 mmol·g-1 and a specific surface area of 602 m2·g-1. The catalytic properties of AC-SO(3)H were compared with that of two commercial solid acid catalysts, Nafion NR50 and Amberlyst-15. In a 10-h esterification reaction of acetic acid with ethanol, the acid conversion with AC-SO(3)H (78%) was lower than that of Amberlyst-15 (86%), which could be attributed to the fact that the SO(3)H density of the sulfonated carbon was lower than that of Amberlyst-15 (4.60 mmol·g-1). However, AC-SO(3)H exhibited comparable and even much higher catalytic activities than the commercial catalysts in the esterification of aliphatic acids with longer carbon chains such as hexanoic acid and decanoic acid, which may be due to the large specific surface area and mesoporous structures of the activated carbon. The disadvantage of AC-SO(3)H is the leaching of SO(3)H group during the reactions. PMID:20956883

Liu, Xiao-Yan; Huang, Miao; Ma, Hai-Long; Zhang, Zeng-Qiang; Gao, Jin-Ming; Zhu, Yu-Lei; Han, Xiao-Jin; Guo, Xiang-Yun

2010-01-01

30

CHANGES IN THE MICROBIOLOGICAL WATER QUALITY ASSOCIATED WITH USING GRANULAR ACTIVATED CARBON IN DRINKING WATER TREATMENT PROCESSES  

Microsoft Academic Search

Granular activated carbon (GAC) is widely used in drinking water treatment for removal of organic compounds, primarily taste, odor, turbidity and the by-products formed during disinfection process. The possibility of replacement the rapid sand filter in the conventional treatment process by activated carbon filter was considered and the effect on microbiological quality of water produced was studied. The study was

Helmy T. El-Zanfaly; A. H. Mostafa; M. H. Mostafa

31

Biological activated carbon process for treatment of potato processing wastewater for in-plant reuse. Technical completion report  

SciTech Connect

Like many other food processing industries, potato processing could create a serious pollution problem. An average-sized processing plant, producing french fries and dehydrated potatoes, can generate a waste load equivalent to a city of 200,000 people. Any discharge of wastes into these waters would immediately result in detrimental effects to the environment. In a plant processing 15,000 tons of potatoes per year, 60 million gallons of water are required. With proper treatment, a large percentage of the wastewater could be reclaimed and reused in the potato processing plant. The scope of the study includes the operation of completely mixed activated sludge (CMAS) reactors as secondary treatment, and anaerobic upflow continuous biological activated carbon (BAC) and biological sand columns as tertiary treatment for potato processing wastewaters.

Hung, Y.T.; Priebe, B.D.

1981-10-01

32

A new mechanism about the process of preparing nanoporous silica with activated carbon mold  

Microsoft Academic Search

Supercritical fluids can be used to proceed nanoscale casting, during which silica precursor dissolved in supercritical CO2 and the supercritical CO2 was in contact with the active carbon templates. After removal of active carbon templates by calcinations, microporous and mesoporous silica samples replicating not only mesostructures, but also macroscopic of active carbon molds were obtained and the product have better

Qun Xu; Kunlun Ding; Liumin He; Jianbo Li; Yiqun Guo; Haijuan Fan

2005-01-01

33

[Water quality safety of ozonation and biologically activated carbon process in application].  

PubMed

Ozonation and biologically activated carbon process, one of advanced treatment technologies, has been applied in many places at home and abroad. However, some emerging water quality problems appeared in operation. Drinking water treatment plant (6 x 10(5) m3/d) with ozonation and biologically activated carbon process (O3-BAC process) was investigated systematically, including microbial safety, the excessive growth of aquatic microorganism and chemical stability of water quality. And some experiments were done in the pilot plant (10 m3/h) at the same time. O3-BAC process is reliable in microbial safety, but operation management should be enhanced. A good number of aquatic microorganisms grow immoderately during operation of O3-BAC process, which is more serious especially in place with high temperature and humidity. With prolong of runtime, the growth of aquatic microorganisms varies regularly. That is hazardous to water quality safety. When raw water is low with alkalinity, decrease of pH in O3-BAC process is obvious. That will seriously affect on chemical stability. PMID:20063746

Qiao, Tie-Jun; Zhang, Xi-Hui

2009-11-01

34

Preparation of sulfurized powdered activated carbon from waste tires using an innovative compositive impregnation process.  

PubMed

The objective of this study is to develop an innovative compositive impregnation process for preparing sulfurized powdered activated carbon (PAC) from waste tires. An experimental apparatus, including a pyrolysis and activation system and a sulfur (S) impregnation system, was designed and applied to produce sulfurized PAC with a high specific surface area. Experimental tests involved the pyrolysis, activation, and sulfurization of waste tires. Waste-tire-derived PAC (WPAC) was initially produced in the pyrolysis and activation system. Experimental results indicated that the Brunauer-Emmett-Teller (BET) surface area of WPAC increased, and the average pore radius of WPAC decreased, as water feed rate and activation time increased. In this study, a conventional direct impregnation process was used to prepare the sulfurized PAC by impregnating WPAC with sodium sulfide (Na2S) solution. Furthermore, an innovative compositive impregnation process was developed and then compared with the conventional direct impregnation process. Experimental results showed that the compositive impregnation process produced the sulfurized WPAC with high BET surface area and a high S content. A maximum BET surface area of 886 m2/g and the S content of 2.61% by mass were obtained at 900 degrees C and at the S feed ratio of 2160 mg Na2S/g C. However, the direct impregnation process led to a BET surface area of sulfurized WPAC that decreased significantly as the S content increased. PMID:15303299

Yuan, Chung-Shin; Lin, Hsun-Yu; Wu, Chun-Hsin; Liu, Ming-Han; Hung, Chung-Hsuang

2004-07-01

35

Application studies of activated carbon derived from rice husks produced by chemical-thermal process—A review  

Microsoft Academic Search

The production of functional activated carbon materials starting from cheap natural precursors using environmentally friendly processes is a highly attractive subject in material chemistry today. Recently, much attention has been focused on the use of plant biomass to produce functional carbonaceous materials, encompassing economic, environmental and social issues. Besides the classical route to produce activated carbons from fossil materials, rice

Yue Chen; Yanchao Zhu; Zichen Wang; Ying Li; Lili Wang; Lili Ding; Xiaoyan Gao; Yuejia Ma; Yupeng Guo

2011-01-01

36

Dewatering Peat With Activated Carbon  

NASA Technical Reports Server (NTRS)

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.

Rohatgi, N. K.

1984-01-01

37

Protein Immobilization on Carbon Nanotubes Via a Two-Step Process of Diimide-Activated Amidation  

SciTech Connect

Carbon nanotubes exhibit interesting electrical, structural and mechanical properties that make them highly promising nanoscale building blocks for the construction of novel functional materials. Many potential applications have been proposed, such as conductive and high-strength composites, field emission displays, fuel cells, sensors, and hydrogen storage media. In addition, biosensors for detecting abnormalities and bio-fuel cells for embedded devices are among the most exciting applications. In order to create the synergy between the biomolecules and nanotubes required to realize these applications, biomolecules, such as proteins and DNAs, must be connected to the carbon nanotubes. This connection can be non-covalent interaction or covalent bonding. There have been several reports on the immobilization of biomolecules on carbon nanotubes, and most of them use non-covalent interaction. The best stability, accessibility and selectivity, however, will be achieved through covalent bonding because of its capability to control the location of the biomolecule, improve stability, accessibility and selectivity and reduce leaching. In the present study, we report the covalent bonding of proteins to nitrogen-doped multiwalled carbon nanotubes (CNx MWNTs) via a two-step process of diimide-activated amidation between the carboxylic acid groups on CNx MWNTs and the amine groups on proteins.

Jiang, Kuiyang; Schadler, Linda S.; Siegel, Richard W.; Zhang, Xinjie; Zhang, Haifeng; Terrones, Mauricio

2004-11-06

38

Carbonic anhydrase activity and biomineralization process in embryos, larvae and adult blue mussels Mytilus edulis L.  

NASA Astrophysics Data System (ADS)

To decide whether a physiological role can be attributed to enzymatic activity with respect to crystal formation and biomineralization of the first larval shell, carbonic anhydrase (CA) activity was measured in embryos and larvae of the blue mussels Mytilus edulis L. Also, CA activity was determined in the mantle edge and gonads of adult mussels with different shell length and condition index. The intention was to find a possible correlation between CA activity and adult shell calcification, i.e. gonadal maturation. The comparison of CA activity in different developmental stages of mussels and the results of an X-ray diffraction study of biomineralization processes in embryonic and larval shells indicate that CA activity is maximal at the end of several developmental stages. Consequently, the increase in CA activity precedes some physiological changes, i.e. the somatoblast 2d formation and the occurrence of the first calcite and quartz crystals in embryos, shell field formation in the gastrula stage, shell gland and periostracum production in trochophores, and rapid aragonite deposition in larval prodissoconch I and prodissoconch II shells. Furthermore, it was found that in adult mussels CA activity was quite variable and that in the mantle edge it was frequently inversely related to the activity in the gonad.

Medakovi?, D.

39

Treatment of Coal Conversion Wastewater with the Powdered Activated Carbon-Contact Stabilization Activated Sludge Process. Third Semiannual Technical Progress Report, August 1, 1981-January 31, 1982.  

National Technical Information Service (NTIS)

The present research project evaluates the effectiveness of the powdered activated carbon-contact stabilization activated sludge process in the treatment of a coke oven wastewater. Nitrification and subsequent denitrification of the contact-stabilization ...

M. T. Suidan C. S. Gee M. A. Deady

1982-01-01

40

Toxicity of carbon nanotubes to the activated sludge process - examination of extracellular polymeric substances  

NASA Astrophysics Data System (ADS)

This thesis examines the effects of two types of single walled carbon nanotubes, namely, long single walled carbon nanotubes (LSWCNTs) and functionalized long single walled carbon nanotubes (FLSWCNTs) on the respiratory activity of the activated sludge microbial communities by a respiration inhibition test. The effectiveness of the extracellular polymeric substances (EPS) in protecting the microbial communities within the activated sludge against the CNTs was determined by using both sheared and unsheared activated sludge. The results showed that CNTs were more toxic under the sheared condition compared to the unsheared condition. LSWCNTS were more toxic towards sheared activated sludge compared to unsheared activated sludge. In case of FLSWCNTs similar inhibition was observed for sheared and unsheared activated sludge and FLSWCNTs were more toxic than LSWCNTs in unsheared activated sludge.

Thakor, Harshrajsinh

41

Adsorption studies on wastewaters from cypermethrin manufacturing process using activated coconut shell carbon.  

PubMed

Cypermethrin is a pyrethroid pesticide and is used in the control of a wide range of insects on crops like vegetables, cereals, maize etc. In the present study, the adsorption efficiency of coconut shell based activated carbon for the removal of color and organic matter from cypermethrin pesticide manufacturing industrial wastewater was investigated. Effect of carbon dosage, pH and contact time on the removal of COD was also studied. Equilibrium and kinetic studies were carried out and the data was fitted in Freundlich and Langmuir models. The study proved that activated coconut shell carbon (acc) is an efficient adsorbent for treatment of cypermethrin industrial wastewaters under study. PMID:18476373

Bhuvaneswari, K; Ravi Prasad, P; Sarma, P N

2007-10-01

42

Treatment of coke-oven wastewater with the powdered activated carbon-contact stabilization activated sludge process. Final report  

SciTech Connect

The objective of the study was to determine optimum parameters for the operation of an innovative process train used in the treatment of coke-over wastewater. The treatment process train consisted of a contact-stabilization activated sludge system with powdered activated carbon (PAC) addition, followed by activated sludge nitrification, followed by denitrification in an anoxic filter. The control and operating parameters evaluated during the study were: (a) the average mixed-liquor PAC concentration maintained in the contact-stabilization system, (b) the solids retention time practiced in the contact-stabilization system, and (c) the hydraulic detention time maintained in the contact aeration tank. Three identical treatement process trains were constructed and employed in this study. The coke-oven wastewater used for this investigation was fed to the treatment units at 30% strength. The first part of the study was devoted to determining the interactions between the mixed liquor PAC concentration and the solids retention time in the contact-stabilization tanks. Results showed that optimum overall system performance is attainable when the highest sludge age (30 day) and highest mixed liquor PAC concentration were practiced. During the second phase of the study, all three systems were operated at a 30 day solids retention time while different detention times of 1, 2/3 and 1/3 day were evaluated in the contact tank. PAC addition rates were maintained at the former levels and, consequently, reduced contact times entailed higher mixed liquor carbon concentrations. Once again, the system receiving the highest PAC addition rate of PAC exhibited the best overall performance. This system exhibited no deterioration in process performance as a result of decreased contact detention time. 72 references, 41 figures, 24 tables.

Suidan, M.T.; Deady, M.A.; Gee, C.S.

1983-11-01

43

GRANULAR ACTIVATED CARBON INSTALLATIONS  

EPA Science Inventory

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

44

Optimum Process Parameters for the Treatment of Landfill Leachate Using Powdered Activated Carbon Augmented Sequencing Batch Reactor (SBR) Technology  

Microsoft Academic Search

The sequencing batch reactor (SBR) process was used for the treatment of raw landfill leachate. Optimum preliminary parameters of leachate\\/activated sludge ratio, powdered activated carbon (PAC) dosage, and settling time were studied. Optimum obtained parameters (mixing ratio of 10%, PAC dosage of 10 g\\/L, and settling time of 1.5 h) were applied on two types of SBRs, namely, non-powdered and powdered activated

Shuokr Qarani Aziz; Hamidi Abdul Aziz; Mohd Suffian Yusoff

2011-01-01

45

The influence of properties within particles of active carbons on selected adsorption processes  

Microsoft Academic Search

In spite of nearly ninety years of production and industrial application, carbonaceous adsorbents, and in particular active carbons, are still an interesting subject of studies, for both experimental researchers and theoreticians dealing with physical chemistry of interfacial phenomena [1].The increasing use of adsorption methods in separation of liquid and gaseous mixtures and in environmental protection leads to the raised demand

B. Buczek

1999-01-01

46

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

SciTech Connect

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

Okwadha, G.D.O.; Li, J.; Ramme, B.; Kollakowsky, D.; Michaud, D. [University of Wisconsin, Milwaukee, WI (United States)

2009-10-15

47

Powdered activated carbon and membrane bioreactors (MBRPAC) for tannery wastewater treatment: long term effect on biological and filtration process performances  

Microsoft Academic Search

This paper describes the findings of an experimental investigation carried out on a pilot scale membrane bioreactor (MBR) with the addition of powdered activated carbon (PAC) to analyze improvements in effluent quality and in the filtration process. The results refer to a pilot plant monitoring stretched over a period of 594 days: 380 without PAC, 123 with a PAC concentration

G. Munz; R. Gori; G. Mori; C. Lubello

2007-01-01

48

Chromate Removal from Wastewater using Micellar Enhanced Ultrafiltration and Activated Carbon Fibre Processes; Validation of Experiment with Mathematical Equations  

Microsoft Academic Search

In this study, chromate and cetylperidinium chloride (CPC) removal from artificial wastewater was monitored by using micellar enhanced ultra- filtration (MEUF) and activated carbon fibre (ACF) adsorption hybrid processes. For the efficient chromate removal, molar concentration of the CPC should be five times that of chromate and it should be at least one critical micelle concentration (CMC). The MEUF was

Rabindra Bade; Seung Hwan Lee

49

Pilot scale study and design of a granular activated carbon regeneration process using supercritical fluids  

SciTech Connect

A technology which has great potential for environmental control and waste remediation is contaminant removal and separation with supercritical fluids (SCF's) or supercritical fluid extraction (SFE). Pressure tuning of solvent power allows SCF processes to adapt to a wide variety of small batch oriented separations typified by environmental cleanup operations. The ability of supercritical CO[sub 2] to extract model contaminant compounds from GAC and subsequently drop out most of the contaminant in a liquid phase has been investigated in a pilot scale apparatus. Typical desorption profiles indicate an 85% removal of the compound from the carbon which allows for reuse. The desorption results have been interpreted with a generalized desorption-mass transfer model. The results of the pilot plant studies have been applied to the design of a fixed-site GAC regeneration unit consisting of a three-element desorber with two-stage flash separation. Optimization of the process centers around minimizing the cost of recycling the SCF through an efficient recompression scheme and cycle configuration in the desorber unit. An economic evaluation shows a processing cost of 10.6 cents/lb (23 cents/kg) GAC which compares favorably with thermal regeneration and incineration. This non-destructive process allows re-use of the GAC while maintaining a high adsorbate capacity, which reduces carbon replacement costs and significantly decreases the need for carbon disposal by landfill or incineration. 25 refs., 13 figs., 3 tabs.

Tomasko, D.L.; Hay, K.J. (Univ. of Illinois, Urbana, IL (United States)); Leman, G.W. (Cabot Corp., Tuscola, IL (United States)); Eckert, C.A. (Georgia Institute of Technology, Atlanta, GA (United States))

1993-08-01

50

Interface structure in carbon and graphite fiber reinforced 2014 aluminum alloy processed with active fiber cooling  

Microsoft Academic Search

The fiber\\/matrix interfaces developed in continuous carbon fiber (CF) and graphite fiber (GRF) reinforced 2014 aluminum matrix composites were characterized using scanning and transmission electron microscopy (TEM). The as-cast CF\\/2014 Al and GRF\\/2014 Al composite specimens were processed by pressure infiltration of continuous fiber bundles preheated at 500°C, while the fiber reinforcements were externally cooled during infiltration by exposing fiber

H. G. Seong; H. F. Lopez; D. P. Robertson; P. K. Rohatgi

2008-01-01

51

Powdered activated carbon augmented activated sludge process for treatment of semi-aerobic landfill leachate using response surface methodology  

Microsoft Academic Search

This study was conducted to investigate aerobic biodegradation of semi-aerobic leachate with and without powdered activated carbon (PAC) addition. The experiment involved operating two 16L laboratory-scale activated sludge reactors in parallel at room temperature and adjusted to pH 6.5±0.5. One of the reactors was supplemented with PAC of 75–150?m size to observe its effect on semi-aerobic leachate biodegradation. Three hydraulic

Nasrin Aghamohammadi; Hamidi bin Abdul Aziz; Mohamed Hasnain Isa; Ali Akbar Zinatizadeh

2007-01-01

52

Production of activated carbons from Illinois coals  

Microsoft Academic Search

Although the predominant use of coal is for combustion applications, more beneficial, reasonable and profitable uses may be as a resource for the production of chemicals, and materials, including activated carbon. Activated carbons represent a family of carbonaceous substances manufactured by processes that develop the carbon`s adsorptive properties. The primary objective of this study was to demonstrate that an activated

E. J. Hippo; Jian Sun

1996-01-01

53

Study on Adsorption Process of Ethanol Vapor to Activated Carbon Fibers  

NASA Astrophysics Data System (ADS)

Performance enhancement of adsorption cooling system has been required for commercial use. Therefore, revealing details of adsorption phenomena are important for optimizing adsorber/desorber heat exchanger which is the bottle-neck of the system. This study deals with the experimental investigation of ethanol vapor adsorption on activated carbon fiber (ACF) under equilibrium condition along with one-dimensional transient numerical simulation of heat and mass transfer in the adsorbent bed is also performed. In order to suggest optimizing method for performance improvement, the present study considered the relationships between cooling capacity and system performance inducing parameters, such as cooling water temperature, ACF height and apparent density in the simulation model. Simulation results agreed well with the experimental data and it is found that the cooling capacity can be enhanced by optimizing ACF bed thickness. Simulation results also shows that the temperatures of adsorber and evaporator do not have significant effects on the optimum adsorption cycle time.

Kariya, Keishi; I. I., El-Sharkawy; Suda, Keisuke; B. B., Saha; Kuwahara, Ken; Koyama, Shigeru

54

Kinetic Processes in Active Medium of Carbon Monoxide Laser Operating on High Vibrational Transitions  

Microsoft Academic Search

Kinetic processes on highly excited vibrational levels of CO molecules pumped by pulsed electron beam sustained discharge are discussed. Temporal behavior of small signal gain (SSG) in active medium of pulsed single-line fundamental band CO laser operating up to 18->17 vibrational band has been studied both theoretically and experimentally with master oscillator power amplifier system. The SSG of pulsed single-line

A. Ionin; A. Kotkov; Yu Klimachev; L. Seleznev; D. Sinitsyn; A. Kurnosov; A. Napartovich; S. Shnyrev; G. Hager; J. McCord

2002-01-01

55

Activated carbon aerogels  

SciTech Connect

Activated carbon aerogels were obtained from the CO{sub 2} activation of the carbon aerogels. The adsorption isotherms of nitrogen on activated carbon aerogels at 77 K were measured and analyzed by the high-resolution {alpha}{sub s} plot to evaluate their porosities. The {alpha}{sub s} plot showed an upward deviation from linearity below {alpha}{sub s} = 0.5, suggesting that the presence of micropores becomes more predominant with the extent of the activation. Activation increased noticeably the pore volume and the surface area (the maximum value: 2600 m{sup 2}.g{sup -1}) without change of the basic network structure of primary particles. Activated carbon aerogels had a bimodal pore size distribution of uniform micropores and mesopores. 16 refs., 2 figs., 1 tab.

Hanzawa, Y.; Kaneko, K. [Chiba Univ. (Japan)] [Chiba Univ. (Japan); Pekala, R.W. [Lawrence Livermore National Lab., CA (United States)] [Lawrence Livermore National Lab., CA (United States); Dresselhaus, M.S. [Massachusetts Inst. of Technology, Cambridge, MA (United States)] [Massachusetts Inst. of Technology, Cambridge, MA (United States)

1996-12-25

56

Powdered activated carbon augmented activated sludge process for treatment of semi-aerobic landfill leachate using response surface methodology.  

PubMed

This study was conducted to investigate aerobic biodegradation of semi-aerobic leachate with and without powdered activated carbon (PAC) addition. The experiment involved operating two 16L laboratory-scale activated sludge reactors in parallel at room temperature and adjusted to pH 6.5+/-0.5. One of the reactors was supplemented with PAC of 75-150microm size to observe its effect on semi-aerobic leachate biodegradation. Three hydraulic retention times (0.92, 1.57 and 2.22 d) and influent COD concentrations (750, 1800 and 2850mg/L) were applied in a factorial design for this study. The results showed enhanced reactor performance due to PAC addition with higher COD, colour and ammoniacal nitrogen removals. The PAC augmented reactor also had higher concentrations of NO(2)-N and NO(3)-N consequent of greater degree of nitrification. PMID:17280831

Aghamohammadi, Nasrin; Aziz, Hamidi Bin Abdul; Isa, Mohamed Hasnain; Zinatizadeh, Ali Akbar

2007-12-01

57

Treatment of gas industry wastes using the biological granular activated carbon fluidized bed reactor process. Annual report, August 1994  

SciTech Connect

The Granular Activated Carbon-Fluidized Bed Reactor (GAC-FBR) system is a high rate process that combines the advantages of biological and physical-chemical treatment in a single unit operation. The process is particularly well-suited to treatment of contaminants present in water and wastewater at relatively low concentrations. Process economics indicate the GAC-FBR can be extremely cost-effective compared to aqueous phase GAC adsorption and air stripping followed by vapor phase control. Accordingly, three field trials are scheduled for the next 18 months; one at a manufactured gas plant site (PAHs), one at a gas dehydration site (BTEX), and one to treat a chlorinated solvent (TCE) at a government installation.

Hickey, R.; Wagner, D.; Sunday, A.; Heine, B.; Rajan, R.

1994-08-01

58

Regional Reactivation of Granular Activated Carbon.  

National Technical Information Service (NTIS)

A major portion of the cost of using Granular Activated Carbon (GAC) as a water treatment unit process is associated with spent carbon replacement or reactivation. Regional reactivation or sharing a reactivation furnace among several users, has been propo...

J. Q. Adams R. M. Clark B. W. Lykins D. Kittredge

1986-01-01

59

Carbon dioxide capture process with regenerable sorbents  

DOEpatents

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

Pennline, Henry W. (Bethel Park, PA); Hoffman, James S. (Library, PA)

2002-05-14

60

Protein Immobilization on Carbon Nanotubes Via a Two-Step Process of Diimide-Activated Amidation  

Microsoft Academic Search

Carbon nanotubes exhibit interesting electrical, structural and mechanical properties that make them highly promising nanoscale building blocks for the construction of novel functional materials. Many potential applications have been proposed, such as conductive and high-strength composites, field emission displays, fuel cells, sensors, and hydrogen storage media. In addition, biosensors for detecting abnormalities and bio-fuel cells for embedded devices are among

Kuiyang Jiang; Linda S. Schadler; Richard W. Siegel; Xinjie Zhang; Haifeng Zhang; Mauricio Terrones

2004-01-01

61

Treatment of Coal-Conversion Wastewater with the Powdered Activated Carbon-Contact-Stabilization Activated-Sludge Process. First Annual Technical Progress Report, February 1, 1981-July 31, 1981.  

National Technical Information Service (NTIS)

The scope of work of the present reseach project is to evaluate the effectiveness of the powdered activated carbon-contact stabilization activated sludge process in the treatment of a coke oven wastewater. Nitrification and subsequent denitrification of t...

M. T. Suidan C. S. Gee M. A. Deady M. Pirbazari

1981-01-01

62

New process for loading highly active platinum on carbon black surface for application in polymer electrolyte fuel cell  

Microsoft Academic Search

The deposition of platinum on various carbon blacks was carried out by forming active functional groups on the surface of the carbon support, and exchanging these active groups with different platinum complexes. Using H2PtCl6 solution, an impregnation rather than an exchange takes place. However, using divalent platinum complexes [Pt(NH3)4]2+, a fast exchange takes place which leads to extremely small platinum

K. Amine; K. Yasuda; H. Takenaka

1998-01-01

63

Solvent-regenerated activated carbon  

SciTech Connect

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

McLaughlin, H. (Fluids Design Corp., Troy, NY (USA))

1988-07-01

64

SIMULTANEOUS MECHANICAL AND HEAT ACTIVATION: A NEW ROUTE TO ENHANCE SERPENTINE CARBONATION REACTIVITY AND LOWER CO2 MINERAL SEQUESTRATION PROCESS COST  

SciTech Connect

Coal can support a large fraction of global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other candidate technologies, which propose long-term storage (e.g., ocean and geological sequestration), mineral sequestration permanently disposes of CO{sub 2} as geologically stable mineral carbonates. Only benign, naturally occurring materials are formed, eliminating long-term storage and liability issues. Serpentine carbonation is a leading mineral sequestration process candidate, which offers large scale, permanent sequestration. Deposits exceed those needed to carbonate all the CO{sub 2} that could be generated from global coal reserves, and mining and milling costs are reasonable ({approx}$4 to $5/ton). Carbonation is exothermic, providing exciting low-cost process potential. The remaining goal is to develop an economically viable process. An essential step in this development is increasing the carbonation reaction rate and degree of completion, without substantially impacting other process costs. Recently, the Albany Research Center (ARC) has accelerated serpentine carbonation, which occurs naturally over geological time, to near completion in less than an hour. While reaction rates for natural serpentine have been found to be too slow for practical application, both heat and mechanical (attrition grinding) pretreatment were found to substantially enhance carbonation reactivity. Unfortunately, these processes are too energy intensive to be cost-effective in their present form. In this project we explored the potential that utilizing power plant waste heat (e.g., available up to {approx}200-250 C) during mechanical activation (i.e., thermomechanical activation) offers to enhance serpentine mineral carbonation, while reducing pretreatment energy consumption and process cost. This project was carried out in collaboration with the Albany Research Center (ARC) to maximize the insight into the potential thermomechanical activation offers. Lizardite was selected as the model serpentine material for investigation, due to the relative structural simplicity of its lamellar structure when compared with the corrugated and spiral structures of antigorite and chrysotile, respectively. Hot-ground materials were prepared as a function of grinding temperature, time, and intensity. Carbonation reactivity was explored using the standard ARC serpentine carbonation test (155 C, 150 atm CO{sub 2}, and 1 hr). The product feedstock and carbonation materials were investigated via a battery of techniques, including X-ray powder diffraction, electron microscopy, thermogravimetric and differential thermal, BET, elemental, and infrared analysis. The incorporation of low-level heat with moderate mechanical activation (i.e., thermomechanical activation) was found to be able to substantially enhance serpentine carbonation reactivity in comparison with moderate mechanical activation alone. Increases in the extent of carbonation of over 70% have been observed in this feasibility study, indicating thermomechanical activation offers substantial potential to lower process cost. Investigations of the thermomechanically activated materials that formed indicate adding low-level heat during moderately intense lizardite mechanical activation promotes (1) energy absorption during activation, (2) structural disorder, and (3) dehydroxylation, as well as carbonation reactivity, with the level of energy absorption, structural disorder and dehydroxylation generally increasing with increasing activation temperature. Increasing activation temperatures were also associated with decreasing surface areas and water absorptive capacities for the activated product materials. The above decreases in surface area and water absorption capacity can be directly correlated with enhanced particle sintering during thermomechanical activation, as evidenced by electron microscopy observation. The level of induced structural disorder appears to be a key parameter in enhancing carbonation reactivity. However, p

M.J. McKelvy; J. Diefenbacher; R. Nunez; R.W. Carpenter; A.V.G. Chizmeshya

2005-01-01

65

Activated carbon for gas separation and storage  

Microsoft Academic Search

Activated carbons offer a large spectrum of pore structures and surface chemistry for adsorption of gases, which are being used to design practical pressure swing and thermal swing adsorption processes for separation and purification of gas mixtures. The activated carbons are often preferred over the zeolitic adsorbents in a gas separation process because of their relatively moderate strengths of adsorption

S. Sircar; T. C. Golden; M. B. Rao

1996-01-01

66

Adsorption characteristics of malachite green on activated carbon derived from rice husks produced by chemical-thermal process.  

PubMed

Phosphoric acid (H(3)PO(4)) and sodium hydroxide (NaOH) treated rice husks, followed by carbonization in a flowing nitrogen were used to study the adsorption of malachite green (MG) in aqueous solution. The effect of adsorption on contact time, concentration of MG and adsorbent dosage of the samples treated or carbonized at different temperatures were investigated. The results reveal that the optimum carbonization temperature is 500 degrees C in order to obtain adsorption capacity that is comparable to the commercial activated carbon for the husks treated by H(3)PO(4). It is interesting to note that MG adsorbed preferably on carbon-rich than on silica rich-sites. It is found that the behaviour of H(3)PO(4) treated absorbent followed both the Langmuir and Freundlich models while NaOH treated best fitted to only the Langmuir model. PMID:15978990

Rahman, I A; Saad, B; Shaidan, S; Sya Rizal, E S

2005-09-01

67

RO brine treatment and recovery by biological activated carbon and capacitive deionization process.  

PubMed

The generation of brine solutions from dense membrane (reverse osmosis, RO or nanofiltration, NF) water reclamation systems has been increasing worldwide, and the lack of cost effective disposal options is becoming a critical water resources management issue. In Singapore, NEWater is the product of a multiple barrier water reclamation process from secondary treated domestic effluent using MF/UF-RO and UV technologies. The RO brine (concentrates) accounts for more than 20% of the total flow treated. To increase the water recovery and treat the RO brine, a CDI based process with BAC as pretreatment was tested. The results show that ion concentrations in CDI product were low except SiO2 when compared with RO feed water. CDI product was passed through a RO and the RO permeate was of better quality including low SiO2 as compared to NEWater quality. It could be beneficial to use a dedicated RO operated at optimum conditions with better performance to recover the water. BAC was able to achieve 15-27% TOC removal of RO brine. CDI had been tested at a water recovery ranging from 71.6 to 92.3%. CDI based RO brine treatment could improve overall water recovery of NEWater production over 90%. It was found that calcium phosphate scaling and organic fouling was the major cause of CDI pressure increase. Ozone disinfection and sodium bisulfite dosing were able to reduce CDI fouling rate. For sustainable operation of CDI organic fouling control and effective organic fouling cleaning should be further studied. PMID:22053461

Tao, Guihe; Viswanath, Bala; Kekre, Kiran; Lee, Lai Yoke; Ng, How Yong; Ong, Say Leong; Seah, Harry

2011-01-01

68

Paracrystalline structure of activated carbons  

NASA Astrophysics Data System (ADS)

Structural studies by means of neutron diffraction of activated carbons, prepared from a polymer of phenol formaldehyde resin by carbonization and activation processes, with variable porosity, are presented. The neutron scattering data were recorded over the range of the scattering vector Q from 2.5 to 500 nm-1. The structure of activated carbons has been described in terms of disordered graphite-like layers with very weak interlayer correlations. The model has been generated by computer simulations and its validity has been tested by comparison of the experimental and calculated intensity functions. Modelling studies have shown that the model containing 3-4 layers each about 2 nm in diameter accounts for the experimental data and that graphite layers are randomly translated and rotated, according to the turbostratic structure. Near-neighbour carbon-carbon distances of about 0.139 nm and 0.154 nm have been determined. The Debye-Waller factor exp (-Q2?2/2) with ? = ?0(r)1/2 suggests a paracrystalline structure within a single layer. The value of the interlayer spacing of 0.36 nm has been found from paracrystalline simulations of the layer arrangement in the c-axis direction. The high quality of the experimental data has enabled determination of the coordination numbers, the interatomic distances and their standard deviations using a curve-fitting procedure over the Q-range from 250 nm to 500 nm, providing structural information about short- and intermediate-range ordering.

Szczygielska, A.; Burian, A.; Dore, J. C.

2001-06-01

69

Activated carbons prepared from phosphoric acid activation of grain sorghum  

Microsoft Academic Search

The production of activated carbons from grain sorghum with phosphoric acid activation has been studied by means of two processes, i.e., one-stage and two-stage. The former comprises simultaneous carbonization and activation after impregnation; the latter, the carbonization of the precursor at 300 °C for 15 min, followed by the activation of the resultant char after impregnation with phosphoric acid. The

Yulu Diao; W. P Walawender; L. T Fan

2002-01-01

70

Sorption Properties of Activated Carbon.  

National Technical Information Service (NTIS)

Equilibrium adsorption isotherms were determined experimentally at several temperatures for GB, GA, and GF on BPL activated carbon and a a super activated coconut carbon. Prediction of these isotherms using experimental DMMP, CC14 and benzene adsorption d...

E. D. Tolles

1968-01-01

71

Solvent-Regenerated Activated Carbon.  

National Technical Information Service (NTIS)

Activated carbon has long been used to remove undesired organic chemicals from aqueous solutions such as wastewaters, public water supplies and contaminated groundwaters. The major problem with the use of activated carbon is the high cost of regenerating ...

H. McLaughlin

1988-01-01

72

Production of active carbons from waste tyres––a review  

Microsoft Academic Search

A review of the production of activated carbons from waste tyres is presented. The effects of various process parameters, particularly, temperature and heating rate, on the pyrolysis stage are reviewed. The influence of activating conditions, physical and chemical, nature of the activation chemicals, on the active carbon properties are discussed. Under certain process conditions several active carbons with BET surface

Edward L. K. Mui; Danny C. K. Ko; Gordon McKay

2004-01-01

73

Regeneration of spent activated carbon  

Microsoft Academic Search

According to this patent application, spent activated carbon is regenerated by contacting it with formaldehyde in an amount sufficient to restore its activation. Following the treatment the regenerated carbon is rinsed to remove residual formaldehyde and is then ready for use. When the activated carbon has lost its reductive and sorbant properties through use, i.e., when it has become 'spent,'

K. Popper; W. M. Camirand; G. S. Williams; E. P. Mecchi

1976-01-01

74

Effects of coconut granular activated carbon pretreatment on membrane filtration in a gravitational driven process to improve drinking water quality  

Microsoft Academic Search

This study evaluates the performance of a polymeric microfiltration membrane, as well as its combination with a coconut granular activated carbon (GAC) pretreatment, in a gravitational filtration module, to improve the quality of water destined to human consumption. The proposed membrane and adsorbent were thoroughly characterized using instrumental techniques, such as contact angle, Brunauer–Emmett–Teller) and Fourier transform infrared spectroscopy analyses.

Flávia Vieira da Silva; Natália Ueda Yamaguchi; Gilselaine Afonso Lovato; Fernando Alves da Silva; Miria Hespanhol Miranda Reis; Maria Teresa Pessoa Sousa de Amorim; Célia Regina Granhen Tavares; Rosângela Bergamasco

2011-01-01

75

Effects of coconut granular activated carbon pretreatment on membrane filtration in a gravitational driven process to improve drinking water quality  

Microsoft Academic Search

This study evaluates the performance of a polymeric microfiltration membrane, as well as its combination with a coconut granular activated carbon (GAC) pretreatment, in a gravitational filtration module, to improve the quality of water destined to human consumption. The proposed membrane and adsorbent were thoroughly characterized using instrumental techniques, such as contact angle, Brunauer–Emmett–Teller) and Fourier transform infrared spectroscopy analyses.

Flávia Vieira da Silva; Natália Ueda Yamaguchi; Gilselaine Afonso Lovato; Fernando Alves da Silva; Miria Hespanhol Miranda Reis; Maria Teresa Pessoa Sousa de Amorim; Célia Regina Granhen Tavares; Rosângela Bergamasco

2012-01-01

76

Gallic acid water ozonation using activated carbon  

Microsoft Academic Search

The ozonation of gallic acid in water in the presence of activated carbon has been studied at pH 5. Hydrogen peroxide, ketomalonic and oxalic acids were identified as by-products. The process involves two main periods of reaction. The first period, up to complete disappearance of gallic acid, during which ozonation rates are slightly improved by the presence of activated carbon.

Fernando J. Beltrán; Juan F. García-Araya; Inés Giráldez

2006-01-01

77

Treatment of Reactive Black 5 by combined electrocoagulation-granular activated carbon adsorption-microwave regeneration process.  

PubMed

Treatment of an azo dye, Reactive Black 5 (RB5) by combined electrocoagulation-activated carbon adsorption-microwave regeneration process was evaluated. The toxicity was also monitored by the Vibrio fischeri light inhibition test. GAC of 100 g L(-1) sorbed 82% of RB5 (100 mg L(-1)) within 4h. RB5-loaded GAC was not effectively regenerated by microwave irradiation (800 W, 30s). Electrocoagulation showed high decolorization of RB5 within 8 min at pH(0) of 7, current density of 277 A m(-2), and NaCl of 1 g L(-1). However, 61% COD residue remained after treatment and toxicity was high (100% light inhibition). GAC of 20 g L(-1) effectively removed COD and toxicity of electrocoagulation-treated solution within 4h. Microwave irradiation effectively regenerated intermediate-loaded GAC within 30s at power of 800 W, GAC/water ratio of 20 g L(-1), and pH of 7.8. The adsorption capacity of GAC for COD removal from the electrocoagulation-treated solution did not significantly decrease at the first 7 cycles of adsorption/regeneration. The adsorption capacity of GAC for removal of both A(265) (benzene-related groups) and toxicity slightly decreased after the 6th cycle. PMID:19932556

Chang, Shih-Hsien; Wang, Kai-Sung; Liang, Hsiu-Hao; Chen, Hsueh-Yu; Li, Heng-Ching; Peng, Tzu-Huan; Su, Yu-Chun; Chang, Chih-Yuan

2010-03-15

78

Nanostructural activated carbons for hydrogen storage  

NASA Astrophysics Data System (ADS)

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 adsorption in activated carbons synthesized from PEEK and poly(ether imide) blends, poly(phenylene oxide), polybenzimidazole and lignin show similar trends. In addition, W( H2) progressively increases as surface area increases for the carbons with similar average pore diameters. Keywords. carbon, activated carbon, poly(ether ether ketone), poly(ether imide), poly(phenylene oxide), polybenzimidazole, lignin, gas adsorption, hydrogen storage

Li, Suoding

79

Modulation of the Initial Mineralization Process of SaOS-2 Cells by Carbonic Anhydrase Activators and Polyphosphate.  

PubMed

Ca-phosphate/hydroxyapatite (HA) crystals constitute the mineral matrix of vertebrate bones, while Ca-carbonate is the predominant mineral of many invertebrates, like mollusks. Recent results suggest that CaCO3 is also synthesized during early bone formation. We demonstrate that carbonic anhydrase-driven CaCO3 formation in vitro is activated by organic extracts from the demosponge Suberites domuncula as well as by quinolinic acid, one component isolated from these extracts. Further results revealed that the stimulatory effect of bicarbonate (HCO3 (-)) ions on mineralization of osteoblast-like SaOS-2 cells is strongly enhanced if the cells are exposed to inorganic polyphosphate (polyP), a linear polymer of phosphate linked by energy-rich phosphodiester bonds. The effect of polyP, administered as polyP (Ca(2+) salt), on HA formation was found to be amplified by addition of the carbonic anhydrase-activating sponge extract or quinolinic acid. Our results support the assumption that CaCO3 deposits, acting as bio-seeds for Ca-carbonated phosphate formation, are formed as an intermediate during HA mineralization and that the carbonic anhydrase-mediated formation of those deposits is under a positive-negative feedback control by bone alkaline phosphatase-dependent polyP metabolism, offering new targets for therapy of bone diseases/defects. PMID:24374859

Wang, Xiaohong; Schröder, Heinz C; Schlossmacher, Ute; Neufurth, Meik; Feng, Qingling; Diehl-Seifert, Bärbel; Müller, Werner E G

2014-05-01

80

Conceptual comparison of pink water treatment technologies: granular activated carbon, anaerobic fluidized bed, and zero-valent iron-Fenton process  

Microsoft Academic Search

Pink water, explosive-laden wastewater produced in army ammunition plants is often treated using expensive and non-destructive granular activated carbon (GAC) adsorption. This paper compares GAC adsorption and two alternative treatment technologies, anaerobic GAC fluidized bed reactor and zero- valent iron-Fenton process. The bench-scale demonstration of the zero-valent iron-Fenton process with real pink water is reported. The features of three technologies

S.-Y. Oh; D. K. Cha; P. C. Chiu; B. J. Kim

81

Making Activated Carbon by Wet Pressurized Pyrolysis  

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

82

REGIONAL REACTIVATION OF GRANULAR ACTIVATED CARBON  

EPA Science Inventory

A major portion of the cost of using Granular Activated Carbon (GAC) as a water treatment unit process is associated with spent carbon replacement or reactivation. Regional reactivation or sharing a reactivation furnace among several users, has been proposed as a means of minimiz...

83

Biomorphic activated porous carbons with complex microstructures from lignocellulosic residues  

Microsoft Academic Search

Transformation of coir fibers, coir pith and coconut shell endocarp microstructures is described for the formation of activated carbons. The carbonization\\/activation process was carried out using ZnCl2 as activating agent at 800°C under CO2 atmosphere. The carbonization\\/activation process was evaluated by TGA\\/DTG measurements which evidenced an increase in the initial decomposition temperature along with increase in the carbon amount as

Jeremias S. Macedo; Larissa Otubo; Odair Pastor Ferreira; Iara de Fátima Gimenez; Italo Odone Mazali; Ledjane Silva Barreto

2008-01-01

84

Activated carbons from sewage sludge  

Microsoft Academic Search

Activated carbons of different characteristics have been prepared from dried sewage sludge using CO2, air and KOH as activating agents. The adsorption capacity of the resulting materials has been checked using 4-chlorophenol as a target compound in aqueous solution. CO2 and air-activation led to carbons of low BET area which increased with the activation temperature but did not reach 100m2\\/g

Victor Manuel Monsalvo; Angel Fernandez Mohedano; Juan Jose Rodriguez

2011-01-01

85

Organic solvent regeneration of granular activated carbon  

NASA Astrophysics Data System (ADS)

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.

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

1982-09-01

86

Process for sequestering carbon dioxide and sulfur dioxide  

DOEpatents

A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

Maroto-Valer, M. Mercedes (State College, PA); Zhang, Yinzhi (State College, PA); Kuchta, Matthew E. (State College, PA); Andresen, John M. (State College, PA); Fauth, Dan J. (Pittsburgh, PA)

2009-10-20

87

Carbon Isotope Ratios in Belowground Carbon Cycle Processes  

Microsoft Academic Search

Abstract Analyses of carbon isotope ratios (?,C values of CO2effluxing from soils, but asof,yet a global,database,is lacking,with which,to test this prediction. Such a global,database,would be a useful input for global carbon cycle models,which,rely on ?values,to constrain source and sink relations. Keywords: global change, ecosystem processes, soil organic carbon, carbon isotope ratio, carbon cycle,

James R. Ehleringer; Nina Buchmann; Lawrence B. Flanagan

2000-01-01

88

Activated Carbon Fibers for Artificial Kidney Devices.  

National Technical Information Service (NTIS)

Activated carbon fibers were made by wet-spinning a dispersion of powdered activated carbon in hydroxyethylcellulose solution. The resulting monofilament had 70% (dry basis) of activated carbon encapsulated in a water-swollen cellulosic binder that was qu...

T. A. Davis

1973-01-01

89

Electrochemical processing of carbon dioxide.  

PubMed

With respect to the negative role of carbon dioxide on our climate, it is clear that the time is ripe for the development of processes that convert CO(2) into useful products. The electroreduction of CO(2) is a prime candidate here, as the reaction at near-ambient conditions can yield organics such as formic acid, methanol, and methane. Recent laboratory work on the 100 A scale has shown that reduction of CO(2) to formate (HCO(2)(-)) may be carried out in a trickle-bed continuous electrochemical reactor under industrially viable conditions. Presuming the problems of cathode stability and formate crossover can be overcome, this type of reactor is proposed as the basis for a commercial operation. The viability of corresponding processes for electrosynthesis of formate salts and/or formic acid from CO(2) is examined here through conceptual flowsheets for two process options, each converting CO(2) at the rate of 100 tonnes per day. PMID:18702129

Oloman, Colin; Li, Hui

2008-01-01

90

CO2 adsorption by activated templated carbons.  

PubMed

Highly porous carbons have been prepared by the chemical activation of two mesoporous carbons obtained by using hexagonal- (SBA-15) and cubic (KIT-6)-ordered mesostructured silica as hard templates. These materials were investigated as sorbents for CO(2) capture. The activation process was carried out with KOH at different temperatures in the 600-800°C range. Textural characterization of these activated carbons shows that they have a dual porosity made up of mesopores derived from the templated carbons and micropores generated during the chemical activation step. As a result of the activation process, there is an increase in the surface area and pore volume from 1020 m(2)g(-1) and 0.91 cm(3)g(-1) for the CMK-8 carbon to a maximum of 2660 m(2)g(-1) and 1.38 cm(3)g(-1) for a sample activated at 800°C (KOH/CMK-8 mass ratio of 4). Irrespective of the type of templated carbon used as precursor or the operational conditions used for the synthesis, the activated samples exhibit similar CO(2) uptake capacities, of around 3.2 mmol CO(2)g(-1) at 25°C. The CO(2) capture capacity seems to depend on the presence of narrow micropores (<1 nm) rather than on the surface area or pore volume of activated carbons. Furthermore, it was found that these porous carbons exhibit a high CO(2) adsorption rate, a good selectivity for CO(2)-N(2) separation and they can be easily regenerated. PMID:21999954

Sevilla, Marta; Fuertes, Antonio B

2012-01-15

91

Waste Activated Sludge Processing.  

National Technical Information Service (NTIS)

A study was made at pilot scale of a variety of processes for dewatering and stabilization of waste activated sludge from a pure oxygen activated sludge system. Processes evaluated included gravity thickening, dissolved air flotation thickening, basket ce...

S. R. Austin J. R. Livingston L. Tortorici

1980-01-01

92

WASTE ACTIVATED SLUDGE PROCESSING  

EPA Science Inventory

A study was made at pilot scale of a variety of processes for dewatering and stabilization of waste activated sludge from a pure oxygen activated sludge system. Processes evaluated included gravity thickening, dissolved air flotation thickening, basket centrifugation, scroll cent...

93

THERMAL REGENERATION OF ACTIVATED CARBON  

EPA Science Inventory

Ecologically, petrochemical wastes constitute a major hazard since waste materials contain relatively large amounts of non-biodegradable and toxic materials which may be discharged continuously. A three-part experimental study of activated carbon adsorption and thermal regenerati...

94

Production of Activated Carbon from Athabasca Oilsands Bitumen  

Microsoft Academic Search

The carbonization process of the pentane insoluble (end-cut) fraction from Athabasca oilsands bitumen in the presence NaOH has been investigated. Chemical activation produced carbon with a well-developed mesoporous structure and a much reduced sulfur content. The yield of the activated carbon increased, whereas sulfur content decreased with an increase in the NaOH load. Physical activation with carbon dioxide resulted in

S. Koutcheiko; T. McCracken; J. Kung; L. Kotlyar

2007-01-01

95

Effects of process parameters on hydrothermal carbonization  

NASA Astrophysics Data System (ADS)

In recent years there has been increased research activity in renewable energy, especially upgrading widely available lignicellulosic biomass, in a bid to counter the increasing environmental concerns related with the use of fossil fuels. Hydrothermal carbonization (HTC), also known as wet torrefaction or hot water pretreatment, is a process for pretreatment of diverse lignocellulosic biomass feedstocks, where biomass is treated under subcritical water conditions in short contact time to produce high-value products. The products of this process are: a solid mass characterized as biochar/biocoal/biocarbon, which is homogeneous, energy dense, and hydrophobic; a liquid stream composed of five and six carbon sugars, various organic acids, and 5-HMF; and a gaseous stream, mainly CO2. A number of process parameters are considered important for the extensive application of the HTC process. Primarily, reaction temperature determines the characteristics of the products. In the solid product, the oxygen carbon ratio decreases with increasing reaction temperature and as a result, HTC biochar has the similar characteristics to low rank coal. However, liquid and gaseous stream compositions are largely correlated with the residence time. Biomass particle size can also limit the reaction kinetics due to the mass transfer effect. Recycling of process water can help to minimize the utility consumption and reduce the waste treatment cost as a result of less environmental impact. Loblolly pine was treated in hot compressed water at 200 °C, 230 °C, and 260 °C with 5:1 water:biomass mass ratio to investigate the effects of process parameters on HTC. The solid product were characterized by their mass yields, higher heating values (HHV), and equilibrium moisture content (EMC), while the liquid were characterized by their total organic carbon content and pH value.

Uddin, Md. Helal

96

Preparation of titania\\/silica mesoporous composites with activated carbon template in supercritical carbon dioxide  

Microsoft Academic Search

Titania\\/silica mesoporous composites have been prepared with nanoscale casting process using activated carbon as template in supercritical carbon dioxide (SC CO2). The composite precursor of tetrabutyl titanate and tetraethyl orthosilicate (TEOS) were dissolved in supercritical CO2, and then coated on activated carbon in the desired supercritical condition. After removal of activated carbon template by calcinations in air at 600°C, TiO2\\/SiO2

Qun Xu; Haijuan Fan; Yiqun Guo; Yanxia Cao

2006-01-01

97

Nanoporous ferric oxide prepared with activated carbon template in supercritical carbon dioxide  

Microsoft Academic Search

Nanoporous ferric oxide has been prepared with nanoscale casting process using activated carbon template in supercritical carbon dioxide. The precursors with the cosolvent of acetone were dissolved in supercritical CO2, and then attached to activated carbon in the supercritical condition. After removal of the activated carbon template by calcinations in air at 873K, the nanoporous Fe2O3 was obtained. Four factors

Haijuan Fan; Qun Xu; Yiqun Guo; Qi Peng; Zhenzhong Hou

2006-01-01

98

Energetic investigation of the adsorption process of CH4, C2H6 and N2 on activated carbon: Numerical and statistical physics treatment  

NASA Astrophysics Data System (ADS)

The adsorption energy distribution (AED) function of a commercial activated carbon (BDH-activated carbon) was investigated. For this purpose, the integral equation is derived by using a purely analytical statistical physics treatment. The description of the heterogeneity of the adsorbent is significantly clarified by defining the parameter N(E). This parameter represents the energetic density of the spatial density of the effectively occupied sites. To solve the integral equation, a numerical method was used based on an adequate algorithm. The Langmuir model was adopted as a local adsorption isotherm. This model is developed by using the grand canonical ensemble, which allows defining the physico-chemical parameters involved in the adsorption process. The AED function is estimated by a normal Gaussian function. This method is applied to the adsorption isotherms of nitrogen, methane and ethane at different temperatures. The development of the AED using a statistical physics treatment provides an explanation of the gas molecules behaviour during the adsorption process and gives new physical interpretations at microscopic levels.

Ben Torkia, Yosra; Ben Yahia, Manel; Khalfaoui, Mohamed; Al-Muhtaseb, Shaheen A.; Ben Lamine, Abdelmottaleb

2014-01-01

99

Ozonation of aniline promoted by activated carbon  

Microsoft Academic Search

The removal of aniline from aqueous solutions by simultaneous use of ozone and activated carbon was investigated at different solution pH. For comparative purposes, single ozonation and adsorption on activated carbon were carried out in the same experimental set-up. In order to evaluate the role of the activated carbon surface chemistry during ozonation, a commercial activated carbon, Norit GAC 1240

P. C. C. Faria; J. J. M. Órfão; M. F. R. Pereira

2007-01-01

100

Effects of free cyanide on microbial communities and biological carbon and nitrogen removal performance in the industrial activated sludge process.  

PubMed

The changes in process performance and microbial communities under free cyanide (CN(-)) were investigated in a lab-scale activated sludge process treating industrial wastewater. The performance of phenol degradation did not appear to be adversely affected by increases in CN(-) concentrations. In contrast, CN(-) was found to have an inhibitory effect on SCN(-) biodegradation, resulting in the increase of TOC and COD concentrations. Nitratation also appeared to be inhibited at CN(-) concentrations in excess of 1.0 mg/L, confirming that nitrite-oxidizing bacteria (NOB) is more sensitive to the CN(-) toxicity than ammonia oxidizing bacteria (AOB). After CN(-) loads were stopped, SCN(-) removal, denitrification, and nitrification inhibited by CN(-) were recovered to performance efficiency of more than 98%. The AOB and NOB communities in the aerobic reactor were analyzed by terminal restriction fragment length (T-RFLP) and quantitative real-time PCR (qPCR). Nitrosomonas europaea lineage was the predominant AOB at all samples during the operation, but an obvious change was observed in the diversity of AOB at the shock loading of 30 and 50 mg/L CN(-), resulting in Nitrosospira sp. becoming dominant. We also observed coexisting Nitrospira and Nitrobacter genera for NOB. The increase of CN(-) loading seemed to change the balance between Nitrospira and Nitrobacter, resulting in the high dominance of Nitrobacter over Nitrospira. Meanwhile, through using the qPCR, it was observed that the nitrite-reducing functional genes (i.e., nirS) were dominant in the activated sludge of the anoxic reactor, regardless of CN(-) loads. PMID:21047665

Kim, Young Mo; Lee, Dae Sung; Park, Chul; Park, Donghee; Park, Jong Moon

2011-01-01

101

Drinking Water Treatment: Activated Carbon Filtration  

NSDL National Science Digital Library

This site, presented by the University of Nebraska - Lincoln Extension, discusses the principles, processes and requirements of activated carbon filtration systems for the domestic (household) user. The site addresses contaminants removed, those not removed, water testing, principals of treatment and the equipment used in this treatment.

Divorak, Bruce I.; Skipton, Sharon

2008-10-21

102

Studies relevant to the catalytic activation of carbon monoxide: the water gas shift reaction and related processes. Technical progress report, December 1, 1983-November 30, 1984  

SciTech Connect

Proposed are investigations related to the catalytic activation of carbon monoxide. These studies will be concerned with the design of catalysts for the water gas shift reaction and related processes such as the hydroformylation of olefins by homogeneous solution phase systems as well as by selected metal catalysts heterogenized by complexation to functionalized polymers. Also under investigation will be quantitative mechanistic aspects of reactions considered key to probable catalyst cycles. These are principally concerned with the fundamental chemistry of metal carbonyl and metal carbonyl hydride complexes including acid/base properties, reductive elimination, substitution and cluster fragmentation reactions and the nucleophilic activation of metal coordinated carbonyls toward reaction with water or dihydrogen. The goal of these studies is to provide chemical guidelines for the molecular design of new and more efficient catalysts for the utilization of carbonaceous materials such as coal for the production of fuels and other organic chemicals. 70 references.

Ford, P.C.

1984-01-01

103

Development of activated carbon pore structure via physical and chemical activation of biomass fibre waste  

Microsoft Academic Search

Biomass waste in the form of biomass flax fibre, produced as a by-product of the textile industry was processed via both physical and chemical activation to produce activated carbons. The surface area of the physically activated carbons were up to 840m2g?1 and the carbons were of mesoporous structure. Chemical activation using zinc chloride produced high surface area activated carbons up

Paul T. Williams; Anton R. Reed

2006-01-01

104

Production of activated carbon from olive bagasse by physical activation  

Microsoft Academic Search

Activated carbons were produced from olive bagasse and their characteristics were investigated. Olive bagasse was first carbonized at 500°C in N2 atmosphere. Then, the obtained chars were activated with steam. The effects of activation temperature and duration were examined. The resultant activated carbons were characterized by measuring their porosities and pore size distributions. The activated carbons produced had the BET

Hakan Demiral; ?lknur Demiral; Belgin Karabacako?lu; Fatma Tümsek

2011-01-01

105

PRODUCTION OF ACTIVATED CARBON FROM SAWDUST USING FLUIDIZED BED REACTOR  

Microsoft Academic Search

ABSTARCT Activated carbon was produced from sawdust by using steam activation in a high temperature muffle furnace. Fast pyrolysis process was carried out prior in fluidized a bed furnace to produce char before activation process. Experiments were conducted to investigate the influence of various process parameters such as particle size, pyrolysis temperature and activation time on the quality of the

MAN KEE LAM; RIDZUAN ZAKARIA

106

Production of activated carbon from rubber wood sawdust  

Microsoft Academic Search

The present work comprehensively addresses various experimental methods reported in the literature and substantiates the use of two-stage activation process with semi-carbonization stage up to 200°C as first stage followed by an activation stage at a desired temperature, for production of activated carbon from carbonaceous precursors using phosphoric acid. Efforts are made towards developing a high surface area activated carbon

C. Srinivasakannan; Mohamad Zailani Abu Bakar

2004-01-01

107

Selecting activated carbon for water and wastewater treatability studies  

Microsoft Academic Search

A series of follow-up investigations were performed to produce data for improving the four-indicator carbon selection method that we developed to identify high-potential activated carbons effective for removing specific organic water pollutants. The carbon's pore structure and surface chemistry are dependent on the raw material and the activation process. Coconut carbons have relatively more small pores than large pores; coal

Wei Zhang; Qi-Gang Chang; Wan-Dong Liu; Bing-Jing Li; Wen-Xin Jiang; Li-Jun Fu; Wei-Chi Ying

2007-01-01

108

Evaluation of solution-processable carbon-based electrodes for all-carbon solar cells.  

PubMed

Carbon allotropes possess unique and interesting physical, chemical, and electronic properties that make them attractive for next-generation electronic devices and solar cells. In this report, we describe our efforts into the fabrication of the first reported all-carbon solar cell in which all components (the anode, active layer, and cathode) are carbon based. First, we evaluate the active layer, on standard electrodes, which is composed of a bilayer of polymer sorted semiconducting single-walled carbon nanotubes and C(60). This carbon-based active layer with a standard indium tin oxide anode and metallic cathode has a maximum power conversion efficiency of 0.46% under AM1.5 Sun illumination. Next, we describe our efforts in replacing the electrodes with carbon-based electrodes, to demonstrate the first all-carbon solar cell, and discuss the remaining challenges associated with this process. PMID:23113673

Ramuz, Marc P; Vosgueritchian, Michael; Wei, Peng; Wang, Chenggong; Gao, Yongli; Wu, Yingpeng; Chen, Yongsheng; Bao, Zhenan

2012-11-27

109

Retinal Light Processing Using Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

Method and system for processing light signals received by the eye of a human or other animal, where the eye may be compromised or non-functioning. Incident light is received at first and second pixels in a photodetector array and provides a pixel electrical signal representing the received light. Each of an array of carbon nanotube (CNT) towers is connected to a pixel, has a first tower end penetrating a retinal active layer of the animal and has a second tower end positioned to receive to receive and transport the pixel electrical signal to the retinal active layer. The CNT tower may be coated with a biologically active substance or chemically modified to promote neurite connections with the tower. The photoreceptor array can be provide with a signal altering mechanism that alters at least one of light intensity and wavelength intensity sensed by a first pixel relative to a second pixel, to correct for one or more selected eye problems.

Loftus, David J. (Inventor); Leng, Theodore (Inventor); Fishman, Harvey (Inventor)

2004-01-01

110

Process and catalyst for hydrogenation of carbon oxides  

US Patent & Trademark Office Database

A process for hydrogenation of carbon oxides comprising contacting a gas mixture containing carbon oxides and of hydrogen with a catalyst comprising bimetallic iron-nickel or iron-cobalt alloys as the active catalytic material supported on a carrier of an oxide. The carrier is preferably formed to have a surface area greater than 20 m.sup.2/g.

2010-09-07

111

Enhanced carbon monoxide utilization in methanation process  

DOEpatents

Carbon monoxide - containing gas streams are passed over a catalyst to deposit a surface layer of active surface carbon thereon essentially without the formation of inactive coke. The active carbon is subsequently reacted with steam or hydrogen to form methane. Surprisingly, hydrogen and water vapor present in the feed gas do not adversely affect CO utilization significantly, and such hydrogen actually results in a significant increase in CO utilization.

Elek, Louis F. (Peekskill, NY); Frost, Albert C. (Congers, NY)

1984-01-01

112

Activation of carboplatin by carbonate.  

PubMed

Carboplatin, [Pt(NH3)2(CBDCA-O,O')], 1, where CBDCA is cyclobutane-1,1-dicarboxylate, is in wide clinical use for the treatment of ovarian, lung, and other types of cancer. Because carboplatin is relatively unreactive toward nucleophiles, an important question concerning the drug is the mechanism by which it is activated in vivo. Using [1H,15N] heteronuclear single quantum coherance spectroscopy (HSQC) NMR and 15N-labeled carboplatin, we show that carboplatin reacts with carbonate ion in carbonate buffer to produce ring-opened products, the nature of which depends on the pH of the medium. The assignment of HSQC NMR resonances was facilitated by studying the reaction of carboplatin in strong acid, which also produces a ring-opened product. The HSQC NMR spectra and UV-visible difference spectra show that reaction of carboplatin with carbonate at pH > 8.6 produces mainly cis-[Pt(NH3)2(CO3(-2))(CBDCA-O)]-2, 5, which contains the mono-dentate CBDCA ligand and mono-dentate carbonate. At pH 6.7, the primary product is the corresponding bicarbonato complex, which may be in equilibrium with its decarboxylated hydroxo analogue. The UV-visible absorption data indicate that the pKb for the protonation of 5 is approximately 8.6. Thus, the reaction of carboplatin with carbonate produces a mixture of ring-opened species that are anions at physiological pH. HSQC NMR studies on 15N-labeled carboplatin in RPMI culture media containing 10% fetal bovine serum with and without added carbonate suggest that carbonate is the attacking nucleophile in culture media. However, because the rate of reaction of carbonate with carboplatin at physiological pH is small, NMR peaks for ring-opened carboplatin were not detected with HSQC NMR. The rate of disappearance of carboplatin in culture medium containing 9 x 10(8) Jurkat cells is essentially the same as that in carbonate buffer, indicating that the ring-opening reaction is not affected by the presence of cells. This work shows that carbonate at concentrations found in culture media, blood, and the cytosol readily displaces one arm of the CBDCA ligand of carboplatin to give a ring-opened product, which at physiological pH is a mixture of anions. These ring-opened species may be important in the uptake, antitumor properties, and toxicity of carboplatin. PMID:16411667

Di Pasqua, Anthony J; Goodisman, Jerry; Kerwood, Deborah J; Toms, Bonnie B; Dubowy, Ronald L; Dabrowiak, James C

2006-01-01

113

Combustion processes for carbon capture  

Microsoft Academic Search

A review of the technologies for coal-based power generation closest to commercial application involving carbon capture is presented. Carbon capture and storage (CCS) developments are primarily adaptations of conventional combustion systems, with additional unit operations such as bulk oxygen supply, CO2 capture by sorbents, CO2 compression, and storage. They use pulverized coal combustion in entrained flow—the dominant current technology for

Terry F. Wall

2007-01-01

114

Water adsorption with hysteresis effect onto microporous activated carbon fabrics  

Microsoft Academic Search

Understanding the adsorption of water vapor onto activated carbons is important for designing processes to remove dilute contaminants\\u000a from humid gas streams, such as providing protection against chemical warfare agents (CWAs), or against toxic industrial compounds\\u000a (TICs) used in a terrorist chemical attack. Water vapor isotherms for Calgon BPL granular activated carbon (GAC), military\\u000a ASZM-TEDA GAC, electrospun activated carbon nanofibers

Patrick D. Sullivan; Brenton R. Stone; Zaher Hashisho; Mark J. Rood

2007-01-01

115

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

National Technical Information Service (NTIS)

The technique of Differential Scanning Calorimetry (DSC) has been applied to the characterization and the analysis of several activated carbons. These activated carbons included BPL carbon (a base carbon), ASC carbon (a BPL carbon impregnated with copper,...

L. E. Cameron S. H. Liang

1991-01-01

116

Plant for the production of activated carbon and electric power from the gases originated in gasification processes  

Microsoft Academic Search

The development of the countries involves a high energy demand; however, the energetic resources used by the moment are not renewable. Events like the energetic crisis of 1973, the continuous geopolitic clashes in energetic resource-rich areas, and the global environmental deterioration as a consequence of the industrial activity taking place in last century, make obvious the need of searching new

J. Gañán; J. P. Turegano; G. Calama; S. Roman; A. Al-Kassir

2006-01-01

117

Production and characterization of granular activated carbon from activated sludge  

Microsoft Academic Search

In this study, activated sludge was used as a precursor to prepare activated carbon using sulfuric acid as a chemical activation agent. The effect of preparation conditions on the produced activated carbon characteristics as an adsorbent was investigated. The results indicate that the produced activated carbon has a highly porous structure and a specific surface area of 580 m 2

Z. Al-Qodah; R. Shawabkah

2009-01-01

118

Activated carbon fibre materials for VOC removal  

Microsoft Academic Search

Activated carbon material has been used for many years in air cleaning applications. Powder form activated carbon has been gradually replaced by activate carbon fibre, which allows much smaller pores - specific area of such material may reach up to 2000 m2\\/g. An experimental dynamic volatile organic compound (VOC) generation system has been developed in order to test new types

P Navarri; D Marchal; A Ginestet

2001-01-01

119

Production of activated carbon from prosopis ( Prosopis juliflora)  

Microsoft Academic Search

Activated carbon was produced from prosopis (Prosopis juliflora), a wild thorny plant grown in wastelands, by chemical activation using zinc chloride. The process variables: activation temperature, level of zinc chloride required and activation duration of 600°C, 50% and 30 min, respectively, yielded 56.9% of activated carbon. The methylene blue adsorbed and zinc chloride recovery were 23 ml and 52.9%, respectively

R Kailappan; L Gothandapani; R Viswanathan

2000-01-01

120

Semicontinuous and continuous degradation of phenol by Pseudomonas putida P8 adsorbed on activated carbon  

Microsoft Academic Search

The semicontinuous and continuous degradation of phenol by Pseudomonas putida P8 which was immobilized on activated carbon was investigated. The amount of bacteria immobilized on the activated carbon surface dependend on the cell concentration in the suspension and on the type of activated carbon. In a continuous process running for four weeks the biomass, which accumulated in the activated carbon

H. M. Ehrhardt; H. J. Rehm

1989-01-01

121

Investigation of microbial safety of a full-scale ozonation and biological activated carbon process under high humidity and temperature conditions.  

PubMed

Microbial safety of a full-scale ozonation and biological activated carbon (BAC) process was investigated by examining pathogens, microbial community and particle counts, with emphasis on the BAC effluent. The process is located at South China, where the average humidity and air temperature were 70-80% and 22-24 °C, respectively. A high diversity of microbial community existed on the BAC media. Three types of dominant bacteria were identified, including Chryseobacterium indologenes, Bacillus brevis and Pseudomonas stutzeri, accounting for 90-95% of total bacteria number. As to pathogenic bacteria and viruses, an opportunistic pathogen, Bacillus cereus, was detected on the BAC. Six types of invertebrates were also observed on the medium, including rotifer, cyclops, nematode, clodecera, nauplius and blood worm. Diversity and number of invertebrates in the BAC effluent were higher than those in the BAC influent. Particle counts were generally less than 50 CNT/mL, with the maximum of 500 CNT/mL during the initial filtration stage after backwashing. PMID:22156135

Qiao, Tiejun; Zhang, Xihui; Wu, Guangxue; Au, Doris W T

2011-01-01

122

The preparation of activated carbon from macadamia nutshell by chemical activation  

Microsoft Academic Search

Different structured activated carbons were prepared from macadamia nutshell by chemical activation with potassium hydroxide and zinc chloride. The influence of process variables on the carbons' pore structure was studied in order to optimise these parameters. The results were also compared with those previously obtained on the chemical activation of coal. The most important parameter in chemical activation with both

A. Ahmadpour; D. D. Do

1997-01-01

123

Activated, coal-based carbon foam  

SciTech Connect

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

Rogers, Darren Kenneth [Wheeling, WV; Plucinski, Janusz Wladyslaw [Glen Dale, WV

2009-06-09

124

Activated carbon adsorption of humic substances  

SciTech Connect

Activated carbon pore-size distribution is an important parameter relative to the carbon's capacity for adsorbing humic substances. The effect of coagulation on adsorption should also be examined wherever granular activated carbon is to be used following coagulation. Experimental investigations using a commercial humic acid and a fulvic acid extracted from peat, and a number of commercial activated carbons, several of which were coal-based, are reported.

Lee, M.C.

1981-08-01

125

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

Microsoft Academic Search

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

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

2006-01-01

126

Characterization of activated carbons from oil-palm shell by CO2 activation with no holding carbonization temperature.  

PubMed

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

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

2013-01-01

127

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

PubMed Central

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

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

2013-01-01

128

DEVELOPMENT OF ACTIVATED CARBONS FROM COAL COMBUSTION BY-PRODUCTS  

SciTech Connect

The increasing role of coal as a source of energy in the 21st century will demand environmental and cost-effective strategies for the use of coal combustion by-products (CCBPs), mainly unburned carbon in fly ash. Unburned carbon is nowadays regarded as a waste product and its fate is mainly disposal, due to the present lack of efficient routes for its utilization. However, unburned carbon is a potential precursor for the production of adsorbent carbons, since it has gone through a devolatilization process while in the combustor, and therefore, only requires to be activated. Accordingly, the principal objective of this work was to characterize and utilize the unburned carbon in fly ash for the production of activated carbons. The unburned carbon samples were collected from different combustion systems, including pulverized utility boilers, a utility cyclone, a stoker, and a fluidized bed combustor. LOI (loss-on-ignition), proximate, ultimate, and petrographic analyses were conducted, and the surface areas of the samples were characterized by N2 adsorption isotherms at 77K. The LOIs of the unburned carbon samples varied between 21.79-84.52%. The proximate analyses showed that all the samples had very low moisture contents (0.17 to 3.39 wt %), while the volatile matter contents varied between 0.45 to 24.82 wt%. The elemental analyses show that all the unburned carbon samples consist mainly of carbon with very little hydrogen, nitrogen, sulfur and oxygen In addition, the potential use of unburned carbon as precursor for activated carbon (AC) was investigated. Activated carbons with specific surface area up to 1075m{sup 2}/g were produced from the unburned carbon. The porosity of the resultant activated carbons was related to the properties of the unburned carbon feedstock and the activation conditions used. It was found that not all the unburned carbon samples are equally suited for activation, and furthermore, their potential as activated carbons precursors could be inferred from their physical and chemical properties. The developed porosity of the activated carbon was a function of the oxygen content, porosity and H/C ratio of the parent unburned carbon feedstock. It was observed that extended activation times and high activation temperatures increased the porosity of the produced activated carbon at the expense of the solid yield. The development of activated carbon from unburned carbon in fly ash has been proven to be a success by this study in terms of the higher surface areas of the resultant activated carbons, which are comparable with commercial activated carbons. However, unburned carbon samples obtained from coal-fired power plants as by-product have high ash content, which is unwanted for the production of activated carbons. Therefore, the separation of unburned carbon from the fly ash is expected to be beneficial for the utilization of unburned carbon to produce activated carbons with low ash content.

Harold H. Schobert; M. Mercedes Maroto-Valer; Zhe Lu

2003-09-30

129

Process for making carbon foam  

SciTech Connect

The process obviates the need for conventional oxidative stabilization. The process employs mesophase or isotropic pitch and a simplified process using a single mold. The foam has a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts. The foam material can be made into a composite which is useful in high temperature sandwich panels for both thermal and structural applications.

Klett, James W. (Knoxville, TN)

2000-01-01

130

Adsorption kinetics of aromatic compounds on carbon nanotubes and activated carbons.  

PubMed

Adsorption kinetics of two organic compounds on four types of carbonaceous adsorbents (a granular activated carbon [HD4000], an activated carbon fiber [ACF10], a single-walled carbon nanotube [SWNT], and a multiwalled carbon nanotube [MWNT]) was examined in aqueous solutions. The times needed for the adsorption to reach apparent equilibrium on the four carbons followed the order of ACF10?>?HD4000?>?SWNT?>?MWNT. Ultrasonication of the carbon nanotubes (CNTs) accelerated their adsorption kinetics but had no effect on their equilibrium adsorption capacities. The pseudo-second order model (PSOM) provided good fitting for the kinetic data. The fitting of kinetic data with the intraparticle diffusion model indicated that external mass transfer controls the sorption process in the organic compound-CNT systems, whereas intraparticle diffusion dominates in the sorption of organic compounds onto activated carbons. PMID:22021047

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

2012-01-01

131

Remarkable activity of PdIr nanoparticles supported on the surface of carbon nanotubes pretreated via a sonochemical process for formic acid electro-oxidation  

NASA Astrophysics Data System (ADS)

It was reported for the first time that the surface treated multi-walled carbon nanotubes supported PdIr (PdIr/CNT-SCP) catalyst presents remarkable electrocatalytic activity and stability for formic acid electro-oxidation (FAEO). The surface of CNTs was functionalized by a sonochemical process for the deposition of PdIr nanoparticles (NPs). The XRD and TEM characterizations show that the prepared PdIr/CNT-SCP catalyst has small mean size and good dispersion of PdIr NPs on CNTs. The electrochemical measurements show that the onset and anodic peak potentials of FAEO on PdIr/CNT-SCP catalyst are 60 and 50 mV more negative than that on the commercial Pd/C catalyst. The mass-normalized peak current density of PdIr/CNT-SCP is 3365 mA mg-1Pd, which is 4.5, 1.4 and 2.7 times higher than that of PdIr/CNT-Untreated, PdIr/C-SCP and commercial Pd/C, respectively. It demonstrates the promotion of Ir and functionalized CNTs to Pd for FAEO.

Chen, Jinwei; Li, Yuanjie; Liu, Shuangren; Wang, Gang; Tian, Jing; Jiang, Chunping; Zhu, Shifu; Wang, Ruilin

2013-12-01

132

Production of activated carbons from almond shell  

Microsoft Academic Search

The production of activated carbons from almond shell, using physical activation by CO2 is reported in this work. The used method has produced activated carbons with apparent BET surface areas and micropore volume as high as 1138m2g?1 and 0.49cm3g?1, respectively. The activated carbons produced have essentially primary micropores and only a small volume of wider micropores. By FTIR analysis it

João M. Valente Nabais; Carlos Eduardo C. Laginhas; P. J. M. Carrott; M. M. L. Ribeiro Carrott

2011-01-01

133

Upgrading Scrap Tire Derived Oils Using Activated Carbon Supported Metal Catalysts  

Microsoft Academic Search

Scrap tire derived oils were upgraded over metal-loaded activated carbon catalysts and commercial catalyst at different operating conditions. Activated carbon support was prepared from the pyrolytic carbon black from pyrolysis of scrap tires. Activated carbon catalysts contained the metal pairs of Co-Ni, Co-Mo, and Ni-Mo. All metal-loaded activated carbon catalysts showed similar catalytic activity for upgrading process at 350°C under

S. Ucar; S. Karagoz; J. Yanik; M. Yuksel; M. Saglam

2007-01-01

134

Phenobarbital interactions with derivatized activated carbon surfaces.  

PubMed

The interactions between phenobarbital and activated carbon surfaces were studied in detail in this work. This was accomplished by utilizing different reagents to manipulate the surface polar functional group compositions of different activated carbons, and determining how those modifications changed phenobarbital adsorption. Oxidation of an activated carbon surface caused a systematic decrease in the basal carbon surface, resulting in a concurrent systematic decrease in the non-specific adsorption of phenobarbital. Even more interesting, it was shown for the first time that chemical reduction of some of the carbonyl-containing functional groups on the activated carbon surface caused a significant increase in the specific adsorption of phenobarbital without any significant effect on the non-specific adsorption. These results support the notion that the OH groups on activated carbon surfaces are the specific adsorption sites for phenobarbital from aqueous solutions, and that the basal carbon surface is the region where non-specific adsorption takes place. PMID:16150453

Aburub, Aktham; Wurster, Dale Eric

2006-04-01

135

JPL Activated Carbon Treatment System (ACTS) for sewage  

NASA Technical Reports Server (NTRS)

An Activated Carbon Treatment System (ACTS) was developed for sewage treatment and is being applied to a one-million gallon per day sewage treatment pilot plant in Orange County California. Activities reported include pyrolysis and activation of carbon-sewage sludge, and activated carbon treatment of sewage to meet ocean discharge standards. The ACTS Sewage treatment operations include carbon-sewage treatment, primary and secondary clarifiers, gravity (multi-media) filter, filter press dewatering, flash drying of carbon-sewage filter cake, and sludge pyrolysis and activation. Tests were conducted on a laboratory scale, 10,000 gallon per day demonstration plant and pilot test equipment. Preliminary economic studies are favorable to the ACTS process relative to activated sludge treatment for a 175,000,000 gallon per day sewage treatment plant.

1976-01-01

136

Activated carbon fiber felt and polymer fiber as biofilm carrier in a modified University of Cape Town process for sewage treatment.  

PubMed

Biofilms on fiber-based carriers have attracted much concern in wastewater treatment processes recently. In this study: (1) a novel sandwich structure fiber-based biofilm carrier was produced, which consisted of an inner core composed of polyacrylonitrile-based activated carbon fiber felt (PAN-ACFF) and an outer coat made of polyester reticular cloth with polypropylene fiber loops; (2) the novel carrier was filled in a step-feeding pilot-scale modified University of Cape Town process (MUCT) for sewage treatment; the MUCT contained a series of pre-anoxic/anaerobic/anoxic-1/anoxic-2/oxic tanks, wherein nitrification liquor was recycled to the anoxic-2 tank and an extra liquor return from the anoxic-1 to the pre-anoxic tank was set up; and (3) the removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were continuously tested for two periods as operational parameters alternated. The optimum values were collected in Period II, when the influent loads were 2,100.6 ± 120.3 gCOD/(d m(3)), 205.5 ± 20.4 gTN/(d m(3)), 39.9 ± 3.9 gTP/(d m(3)), the removal percentages were 93.1 ± 1.1% of COD, 39.4 ± 3.5% of TN, and 84.6 ± 3.4% of TP. For COD, NH4(+)-N, and TP, the specific removal loads of filler were 291.5 ± 18.2, 22.9 ± 3.1, 4.8 ± 0.5 (g d)/kg. PMID:24037168

Zhou, Dongkai

2013-01-01

137

The process of dimethyl carbonate to diphenyl carbonate: thermodynamics, reaction kinetics and conceptual process design  

Microsoft Academic Search

Diphenyl carbonate (DPC) is a precursor in the production of Polycarbonate (PC), a widely employed engineering plastic. To overcome the drawbacks of the traditional PC process - e.g. phosgene as a reactant and methylene chloride as solvent- a new process route starting from Dimethyl carbonate (DMC) via Methyl Phenyl carbonate (MPC) to DPC is investigated in this thesis.\\u000aFirst the

Jens Haubrock

2007-01-01

138

Adsorption of chlorophenols on granular activated carbon  

SciTech Connect

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

Yang, M.

1993-12-31

139

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

NASA Astrophysics Data System (ADS)

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

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

140

Purification process for vertically aligned carbon nanofibers  

NASA Technical Reports Server (NTRS)

Individual, free-standing, vertically aligned multiwall carbon nanotubes or nanofibers are ideal for sensor and electrode applications. Our plasma-enhanced chemical vapor deposition techniques for producing free-standing and vertically aligned carbon nanofibers use catalyst particles at the tip of the fiber. Here we present a simple purification process for the removal of iron catalyst particles at the tip of vertically aligned carbon nanofibers derived by plasma-enhanced chemical vapor deposition. The first step involves thermal oxidation in air, at temperatures of 200-400 degrees C, resulting in the physical swelling of the iron particles from the formation of iron oxide. Subsequently, the complete removal of the iron oxide particles is achieved with diluted acid (12% HCl). The purification process appears to be very efficient at removing all of the iron catalyst particles. Electron microscopy images and Raman spectroscopy data indicate that the purification process does not damage the graphitic structure of the nanotubes.

Nguyen, Cattien V.; Delziet, Lance; Matthews, Kristopher; Chen, Bin; Meyyappan, M.

2003-01-01

141

Influence of pyrolysis conditions on pore development of oil-palm-shell activated carbons  

Microsoft Academic Search

Oil-palm shells were used to prepare activated carbons. The shells were first subjected to a pyrolysis process and the resulting chars were then treated under a physical activation process in the presence of carbon dioxide. The influences of the operating pyrolysis parameters on the activated carbon were investigated in particular. These parameters included the pyrolysis temperature and hold time, the

Aik Chong Lua; Fong Yow Lau; Jia Guo

2006-01-01

142

Active braze process  

SciTech Connect

Active metal bonding using Cusil (silver-copper) braze alloys is a well established method used at GE Neutron Devices (GEND) for bonding metal to metal, metal to ceramics, and ceramics to ceramics. However, there are many instances in which using a silver alloy for bonding is undesirable (e.g., in vacuum tube envelopes, or where sequential braze steps at different temperatures are required to complete an assembly). The Material and Processes Laboratory at GEND has discovered a new method of active brazing with non-silver alloys which has proved especially successful in ceramic-to-ceramic joints. This method has the added advantage of eliminating several steps which are required in conventional bonding techniques. 2 figs., 10 tabs.

Levine, I.L.; Pike, R.A.

1990-11-02

143

Modeling carbonizing process in fluidized bed  

NASA Astrophysics Data System (ADS)

This paper presents possibility of using neural networks model for designing carbonizing process in fluidized bed. This process is very complicated and difficult as multi-parameters changes are non linear and car drive cross structure is non homogeneous. This fact and lack of mathematical algorithms describing this process makes modeling properties of drives elements by traditional numerical methods difficult or even impossible. In this case it is possible to try using artificial neural network. Using neural networks for modeling carbonizing in fluidized bed is caused by several nets' features: non linear character, ability to generalize the results of calculations for data out of training set, no need for mathematical algorithms describing influence changes input parameters on modeling materials properties. The neural network structure is designed and special prepared by choosing input and output parameters of process. The method of learning and testing neural network, the way of limiting nets structure and minimizing learning and testing error are discussed. Such prepared neural network model, after putting expected values of car cross driving properties in output layer, can give answers to a lot of questions about running carbonizing process in fluidized bed. The practical implications of the neural network models are possibility of using they to build control system capable of on-line controlling running process and supporting engineering decision in real time. The originality of this research is different conception to obtain foreseen materials properties after carbonizing in fluidized bed. The specially prepared neural networks model could be a help for engineering decisions and may be used in designing carbonizing process in fluidized bed as well as in controlling changes of this process.

Szota, M.; Jasinski, J.

2010-06-01

144

Carbon dioxide reduction by the Bosch process  

NASA Technical Reports Server (NTRS)

Prototype units for carrying out the reduction of carbon dioxide to elementary carbon have been built and operated successfully. In some cases, however, startup difficulties have been reported. Moreover, the recycle reactor product has been reported to contain only small amounts of water and undesirably high yields of methane. This paper presents the results of the first phase of an experimental study that was carried out to define the mechanisms occurring in the reduction process. Conclusions are drawn and possible modifications to the present recycle process are suggested.

Manning, M. P.; Reid, R. C.

1975-01-01

145

Catalytic dehydrogenative coupling of methane on active carbon. Effect of metal supported on active carbon  

Microsoft Academic Search

Ethane, ethene, ethyne and hydrogen are obtained in good yields via dehydrogenative coupling of methane in the presence of active carbon as a catalyst. The product yield is increased by supporting metal on active carbon.

H. Yagita; A. Ogata; A. Obuchi; K. Mizuno; T. Maeda; K. Fujimoto

1996-01-01

146

Activated carbon fiber composite material and method of making  

DOEpatents

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

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

2000-01-01

147

Activated carbon fiber composite material and method of making  

DOEpatents

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

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

2001-01-01

148

Production and characterization of lignocellulosic biomass-derived activated carbon.  

PubMed

The goal of this work is to establish the technical feasibility of producing activated carbon from pulp mill sludges. KOH chemical activation of four lignocellulosic biomass materials, two sludges from pulp mills, one sludge for a linerboard mill, and cow manure, were investigated experimentally, with a focus on the effects of KOH/biomass ratio (1/1, 1.5/1 and 2/1), activation temperature (400-600 °C) and activation time (1 to 2 h) on the development of porosity. The activation products were characterized for their physical and chemical properties using a surface area analyzer, scanning electron microscopy and Fourier transform infrared spectroscopy. Experiments were carried out to establish the effectiveness of the lignocellulosic biomass-derived activated carbon in removing methylene blue (MB), a surrogate of large organic molecules. The results show that the activated carbon are highly porous with specific surface area greater than 500 m²/g. The yield of activated carbon was greater than the percent of fixed carbon in the dry sludge, suggesting that the activation process was able to capture a substantial amount of carbon from the organic matter in the sludge. While 400 °C was too low, 600 °C was high enough to sustain a substantial rate of activation for linerboard sludge. The KOH/biomass ratio, activation temperature and time all play important roles in pore development and yield control, allowing optimization of the activation process. MB adsorption followed a Langmuir isotherm for all four activated carbon, although the adsorption capacity of NK-primary sludge-derived activated carbon was considerably lower than the rest, consistent with its lower specific surface area. PMID:21099052

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

2010-01-01

149

Characterization and application of activated carbon produced from oak cups pulp  

Microsoft Academic Search

Activated carbons have been prepared from a lignocellulosic waste material by chemical activation. Phosphoric acid and zinc chloride have been used as activating agent. The influence of process variables on the carbons’ surface area was studied to optimize these parameters. The textural properties of active carbons were characterized by N2 adsorption at 77K and SEM analysis, while Boehm titration and

Serkan Timur; Ismail Cem Kantarli; Sermin Onenc; Jale Yanik

2010-01-01

150

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

Microsoft Academic Search

A novel, three-step process for the production of high-quality activated carbons from macadamia nut shell and coconut shell charcoals is described. In this process the charcoal is (1) heated to a high temperature (carbonized), (2) oxidized in air following a stepwise heating program from low (ca. 450 K) to high (ca. 660 K) temperatures (oxygenated), and (3) heated again in

Man S. Tam; Michael Jerry Antal

1999-01-01

151

A novel carbon-based process for flue gas cleanup  

SciTech Connect

The objective of this project is to demonstrate the preliminary technical and economic feasibility of a novel carbon-based process for removal of at least 95% SO{sub 2} and at least 75% NO{sub x} from coal combustion flue gas. In the process, flue gas leaving the electrostatic precipitator (ESP) is passed through a trickle bed of activated carbon catalyst employing a periodic flush of low strength sulfuric acid. The SO{sub 2} is oxidized to SO{sub 3} and removed as medium strength sulfuric acid. The SO{sub 2}-free flue gas is then mixed with NH{sub 3}, and the NO{sub x} in the gas is subjected to selective catalytic reduction (SCR) to N{sub 2} over a fixed-bed of activated carbon catalyst.

Gangwal, S.K. (Research Triangle Inst., Research Triangle Park, NC (United States)); Silveston, P.L. (Waterloo Univ., ON (Canada))

1992-01-01

152

A novel carbon-based process for flue gas cleanup  

SciTech Connect

The objective of this project is to demonstrate the preliminary technical and economic feasibility of a novel carbon-based process for removal of at least 95% SO{sub 2} and at least 75% NO{sub x} from coal combustion flue gas. In the process, flue gas leaving the electrostatic precipitator (ESP) is passed through a trickle bed of activated carbon catalyst employing a periodic flush of low strength sulfuric acid. The SO{sub 2} is oxidized to SO{sub 3} and removed as medium strength sulfuric acid. The SO{sub 2}-free flue gas is then mixed with NH{sub 3}, and the NO{sub x} in the gas is subjected to selective catalytic reduction (SCR) to N{sub 2} over a fixed bed of activated carbon catalyst.

Silveston, P.L.

1992-04-01

153

ACTIVATED CARBON FROM LIGNITE FOR WATER TREATMENT  

Microsoft Academic Search

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

Edwin S. Olson; Daniel J. Stepan

2000-01-01

154

Oxygen reduction activity of carbon nitride supported on carbon nanotubes.  

PubMed

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

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

2012-06-01

155

Processing of porous carbon with tunable pore structure by the carbide-derived carbon method  

NASA Astrophysics Data System (ADS)

Biomorphic TiC ceramics were covered with highly porous carbon, so-called carbide-derived carbon (CDC), by selective etching of Ti with chlorine in a temperature range between 400° C and 1,200°C. Microporous carbon with narrow pore size distribution was obtained at temperature ranging from 400°C to 800°C. Chlorination at higher temperatures leads to formation of mesopores because of increased degree of order of the obtained CDC. A higher etching rate as well as higher degree of order at lower reaction temperature was observed if a catalytically active metal like Fe or Ru was presented during the chlorination process. This is associated with an increased amount of mesopores and with a decrease in specific surface area. Therefore, the CDC processing in the presence of a catalyst offers another way to produce ordered carbon structures at lower temperatures.

Popovska, Nadejda; Kormann, Martina

2010-06-01

156

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

157

The effect of carbonization temperature of PAN fiber on the properties of activated carbon fiber composites  

Microsoft Academic Search

The PAN (polyacrylonitrile) based carbon fiber composites were prepared from mixtures of chopped carbon fibers and phenolic resin. Two different carbon fibers were obtained by carbonization of stabilized PAN fiber precursors in nitrogen at 1073 and 1273 K, respectively. Samples of activated carbon fiber composites (ACFCs) were prepared from the carbon fiber composites by activation in carbon dioxide at 1123

J. C. Lee; B. H. Lee; B. G. Kim; M. J. Park; D. Y. Lee; I. H. Kuk; H. Chung; H. S. Kang; H. S. Lee; D. H. Ahn

1997-01-01

158

Catalytic pyrolysis of CHF 3 over activated carbon and activated carbon supported potassium catalyst  

Microsoft Academic Search

The catalytic activity of activated carbon (AC) and activated carbon supported potassium for the decomposition of CHF3 was investigated at temperatures between 873 and 1173K and at a space velocity of 4300h?1. It is found that activated carbon supported potassium shows high and relatively stable activity during the pyrolysis of CHF3 under the conditions studied. Compared with the gas phase

Wenfeng Han; Eric M. Kennedy; Huazhang Liu; Ying Li; Adesoji A. Adesina; John C. Mackie; Bogdan Z. Dlugogorski

2010-01-01

159

Preparation of activated carbons from oil-palm-stone chars by microwave-induced carbon dioxide activation  

Microsoft Academic Search

A novel method of preparing activated carbons from oil-palm-stone chars by microwave-induced CO2 reaction was studied in this paper. The effects of processing parameters (gas flow rate, input microwave power and exposure time to microwave energy) and the presence of CuO receptors on the characteristics of the activated carbons were investigated in order to determine and optimise the control parameters

Jia Guo; Aik Chong Lua

2000-01-01

160

Reprocessing of used tires into activated carbon and other products  

SciTech Connect

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

Teng, H.; Serio, M.A.; Wojtowicz, M.A.; Bassilakis, R.; Solomon, P.R. [Advanced Fuel Research, Inc., East Hartford, CT (United States)

1995-09-01

161

Sorption of elemental mercury by activated carbons  

Microsoft Academic Search

The paper gives results of a study of the mechanisms and rate of elemental mercury (Hg) capture by activated carbons, using a bench-scale apparatus. Three types of activated carbons, two thermally activated (PC-100 and FGD) and one impregnated with elemental sulfur (S) (HGR), were used to study the effects of surface area (approximately 550-1000 sq m\\/g), sorption temperature (23-140 C),

S. V. Krishnan; Brian K. Gullett; Wojciech Jozewicz

1994-01-01

162

Processing, characterization and modeling of carbon nanofiber modified carbon/carbon composites  

NASA Astrophysics Data System (ADS)

Carbon/Carbon (C/C) composites are used in high temperature applications because they exhibit excellent thermomechanical properties. There are several challenges associated with the processing of C/C composites that include long cycle times, formation of closed porosity within fabric woven architecture and carbonization induced cracks that can lead to reduction of mechanical properties. This work addresses various innovative approaches to reduce processing uncertainties and thereby improve thermomechanical properties of C/C by using vapor grown carbon nanofibers (VGCNFs) in conjunction with carbon fabric and precursor phenolic matrix. The different aspects of the proposed research contribute to understanding of the translation of VGCNFs properties in a C/C composite. The specific objectives of the research are; (a) To understand the mechanical properties and microstructural features of phenolic resin precursor with and without modification with VGCNFs; (b) To develop innovative processing concepts that incorporate VGCNFs by spraying them on carbon fabric and/or adding VGCNFs to the phenolic resin precursor; and characterizing the process induced thermal and mechanical properties; and (c) To develop a finite element model to evaluate the thermal stresses developed in the carbonization of carbon/phenolic with and without VGCNFs. Addition of VGCNFs to phenolic resin enhanced the thermal and physical properties in terms of flexure and interlaminar properties, storage modulus and glass transition temperature and lowered the coefficient of thermal expansion. The approaches of spraying VGCNFs on the fabric surface and mixing VGCNFs with the phenolic resin was found to be effective in enhancing mechanical and thermal properties of the resulting C/C composites. Fiber bridging, improved carbon yield and minimization of carbonization-induced damage were the benefits of incorporating VGCNFs in C/C composites. Carbonization induced matrix cracking predicted by the finite element model is consistent with that observed experimentally. The finite element model is supported by a modification of a shear-lag model that describes the load transfer of a crack at the fiber/matrix interface.

Samalot Rivera, Francis J.

163

Adsorption and Stability of Mercury on Different Types of Impregnated Activated Carbon  

Microsoft Academic Search

A method for control of mercury emissions from combustion processes involves removal of elemental mercury from the flue gas by injection of activated carbon. The adsorption and stability of mercury was determined on a commercial activated carbon and two activated carbons that were impregnated with bromine and chlorine. The results of the adsorption experiments show Hg sorption capacities of bromine

Mingxia Fan; Shitang Tong; Charles Q. Jia; Lei Mao; Yanqun Li; Xinzhi Zhang

2011-01-01

164

Pore structure and adsorption properties of activated carbon prepared from granular molded waste paper  

Microsoft Academic Search

We have previously manufactured activated carbon using waste paper board, which was prepared by adding 8% phenol resin adhesive to torn waste newspaper and hot-pressing. In this study, the pretreatment process of the raw material was simplified; the waste paper was extruded to form granules. The activated carbon was manufactured by the carbon dioxide activation method using the granules as

Masahiro Shimada; Takahiko Iida; Kensuke Kawarada; Yoshifumi Chiba; Toshihiro Mamoto; Takayuki Okayama

2004-01-01

165

Carbon formation and metal dusting in advanced coal gasification processes  

SciTech Connect

The product gases generated by coal gasification systems contain high concentrations of CO and, characteristically, have relatively high carbon activities. Accordingly, carbon deposition and metal dusting can potentially degrade the operation of such gasifier systems. Therefore, the product gas compositions of eight representative gasifier systems were examined with respect to the carbon activity of the gases at temperatures ranging from 480 to 1,090 C. Phase stability calculations indicated that Fe{sub 3}C is stable only under very limited thermodynamic conditions and with certain kinetic assumptions and that FeO and Fe{sub 0.877}S tend to form instead of the carbide. As formation of Fe{sub 3}C is a necessary step in the metal dusting of steels, there are numerous gasifier environments where this type of carbon-related degradation will not occur, particularly under conditions associated with higher oxygen and sulfur activities. These calculations also indicated that the removal of H{sub 2}S by a hot-gas cleanup system may have less effect on the formation of Fe{sub 3}C in air-blown gasifier environments, where the iron oxide phase can exist and is unaffected by the removal of sulfur, than in oxygen-blown systems, where iron sulfide provides the only potential barrier to Fe{sub 3}C formation. Use of carbon- and/or low-alloy steels dictates that the process gas composition be such that Fe{sub 3}C cannot form if the potential for metal dusting is to be eliminated. Alternatively, process modifications could include the reintroduction of hydrogen sulfide, cooling the gas to perhaps as low as 400 C and/or steam injection. If higher-alloy steels are used, a hydrogen sulfide-free gas may be processed without concern about carbon deposition and metal dusting.

DeVan, J.H.; Tortorelli, P.F.; Judkins, R.R.; Wright, I.G.

1997-02-01

166

Activated carbons and double layer capacitance  

Microsoft Academic Search

The porous structures and electrochemical double layer capacitance of activated carbon microbeads and carbon fibers were investigated using nitrogen gas adsorption and electrochemical constant current cycling (CCC) methods. Porous structural information on pore size distribution (PSD) and surface area were extracted through a gas adsorption analysis program based on density functional theory (DFT). The relation between the porous surface areas

Hang Shi

1996-01-01

167

Vapor Phase Impregnation of Active Carbons.  

National Technical Information Service (NTIS)

The purpose of the research was to study methods for the vapor deposition of metals and metal salts into the pores of activated carbons, and evaluate properties imparted to the carbons for toxic gas removal by this method of impregnation. A successful met...

D. M. Andrews J. P. Redmond

1969-01-01

168

Activated Carbon Fibers for Artificial Kidney Devices.  

National Technical Information Service (NTIS)

Filaments made by wet-spinning a dispersion of powdered activated carbon in hydroxyethylcellulose solution have 70% (w/w, dry basis) of the absorbent carbon encapsulated in a water-swollen cellulosic binder that is permeable to solutes with molecular weig...

T. A. Davis

1974-01-01

169

78 FR 13894 - Certain Activated Carbon From China  

Federal Register 2010, 2011, 2012, 2013

...731-TA-1103 (Review)] Certain Activated Carbon From China Determination On...antidumping duty order on certain activated carbon from China would be likely to...February 2013), entitled Certain Activated Carbon from China: Investigation...

2013-03-01

170

Preparation and characteristics of agricultural waste activated carbon by physical activation having micro- and mesopores  

Microsoft Academic Search

Micro–mesoporous activated carbons were prepared from various agricultural wastes by physical activation. Agricultural wastes such as macadamia nut-shell, corncob, bagasse bottom ash, sawdust fly ash and rice husk fly ash, were optimized and processed to obtain the highest surface area. The effects of the amount of volatile matter in char, the activating agent, the activating temperature and kind of raw

Amphol Aworn; Paitip Thiravetyan; Woranan Nakbanpote

2008-01-01

171

Studies relevant to the catalytic activation of carbon monoxide  

SciTech Connect

Research activity during the current funding period (December 87 to present) of this grant has included continued mechanistic investigations of the nucleophilic activation of carbon monoxide such as homogeneous catalysis of the water gas shift and key steps in the relevant catalytic cycles. In addition, new investigations of related processes involved in the catalytic activation of carbon monoxide and other C{sub 1} compounds were initiated. These include the application of fast reaction techniques to prepare and to investigate quantitatively reactive organometallic intermediates relevant to the activation of hydrocarbons toward carbonylation and other functionalizations. 39 refs., 7 figs.

Ford, P.C.

1990-05-11

172

Gas Adsorption by Activated and Impregnated Carbons.  

National Technical Information Service (NTIS)

An assembly has been constructed for measuring equilibrium absorption isotherms on activated and impregnated carbons. The pumping system, pressure-measuring devices and microbalance assembly have been tested. Construction of the fume hood exhaust and filt...

P. J. Reucroft C. T. Chiou

1975-01-01

173

ACTIVATED CARBON ADSORPTION OF TRACE ORGANIC COMPOUNDS  

EPA Science Inventory

Research was conducted to determine how effectively humic substances and the trace contaminants 2-methylisoborneol (MIB), geosmin, the chlorophenols and polynuclear aromatic hydrocarbons were adsorbed by activated carbon under the competitive adsorption conditions encountered in ...

174

Prebiotic Activation Processes  

Microsoft Academic Search

A series of reactions involving urea, imidazole, and magnesium can result in the activation of nucleotides and amino acids to form polymers. Unlike any which have been suggested before, these reactions have parallels in contemporary biological mechanisms.

R. Lohrmann; L. E. Orgel

1973-01-01

175

Separation of C 60\\/C 70 mixture on activated carbon and activated carbon fibres  

Microsoft Academic Search

The possibilities for preparative separation of fullerene (C60\\/C70) mixture by flash chromatography on activated carbon or activated carbon fibres as a stationary phase are shown. The effect of the nature of the activated carbon and of its specific surface area on the elution time, Chromatographic peak width, amount, and purity of the recovered product (C60 or C70) was studied. Different

Nevena Manolova; Iliya Rashkov; Denis Legras; sandrine Delpeux; Francois Beguin

1995-01-01

176

Bromate removal during transition from new granular activated carbon (GAC) to biological activated carbon (BAC)  

Microsoft Academic Search

Bromate removal by activated carbon after ozonation is a subject of concern, since bromate is commonly found in the ozonation of bromide-containing water. Though new GAC (granular activated carbon) shows the capacity to reduce bromate to bromide, in the long-term use of GAC following ozonation, its bromate removal rate apparently decreases during transition from new GAC to BAC (biological activated

Mari Asami; Takako Aizawa; Takayuki Morioka; Wataru Nishijima; Akihisa Tabata; Yasumoto Magara

1999-01-01

177

Activated Carbon and Carbon Black Catalyzed Transformation of Aqueous Ozone into OH-Radicals  

Microsoft Academic Search

In an ozone-containing water a suspension of a few milligrams per liter of activated carbon (AQ or carbon black (CB) initiates a radical-type chain reaction that then proceeds in the aqueous phase and accelerates the transformation of O3 into secondary radicals, such as hydroxyl radicals (°OH). This results in an Advanced Oxidation Process (AOP) that is similar to an O3-based

Urs Jans; Jürg Hoigné

1998-01-01

178

Agricultural residues as precursors for activated carbon production—A review  

Microsoft Academic Search

A review of the production of activated carbons from agricultural residues is presented. The effects of various process parameters on the pyrolysis stage are reviewed. Influences of activating conditions, physical and chemical, on the active carbon properties are discussed. Under certain process conditions several active carbons with BET surface areas, ranging between 250 and 2410m2\\/g and pore volumes of 0.022

O. Ioannidou; A. Zabaniotou

2007-01-01

179

Biogas pre-upgrading by adsorption of trace compounds onto granular activated carbons and an activated carbon fiber-cloth.  

PubMed

The study assesses the adsorption onto activated carbon materials of selected volatile organic compounds -VOCs- (dichloromethane, 2-propanol, toluene, siloxane D4) in a biogas matrix composed of methane and carbon dioxide (55:45 v/v). Three different adsorbents are tested, two of them are granular activated carbon (GAC), and the last is an activated carbon fiber-cloth (ACFC). The adsorption isotherm data are fitted by different models by nonlinear regression. The Langmuir-Freundlich model appears to be the adequate one to describe the adsorption phenomena independently of the VOC considered or the adsorbent. The adsorbents present attractive adsorption capacity of the undesirable compounds in biogas atmosphere though the maximum adsorption capacities for a VOC are quite different from each other. The adsorption kinetics are characterized through three coefficients: the initial adsorption coefficient, the external film mass transfer coefficient and the internal diffusion coefficient of Weber. The ACFC demonstrates advanced kinetic yields compared to the granular activated carbon materials whatever VOC is considered. Therefore, pre-upgrading of biogas produced from wastewater sludge or co-digestion system by adsorption onto activated carbon appears worth investigating. Especially with ACFC material that presents correct adsorption capacities toward VOCs and concrete regeneration process opportunity to realize such process. PMID:19273892

Boulinguiez, B; Le Cloirec, P

2009-01-01

180

A novel carbon-based process for flue gas cleanup  

SciTech Connect

The objective of this project is to demonstrate the preliminary technical and economic feasibility of a novel carbon-based process for removal of at least 95% SO{sub 2} and at least 75% NO{sub x} from coal combustion flue gas. In the process, flue gas leaving the electrostatic precipitator (ESP) is passed through a trickle bed of activated carbon catalyst employing a periodic flush of low strength sulfuric acid. The SO{sub 2} is oxidized to SO{sub 3} and removed as medium strength sulfuric acid. The SO{sub 2}-free flue gas is then mixed with NH{sub 3}, and the NO{sub x} in the gas is subjected to selective catalytic reduction (SCR) to N{sub 2} over a fixed bed of activated carbon catalyst. In the previous three quarters, a detailed project management plan was prepared describing the experimental setup, work plan, and test plan. The experimental system was completed for SO{sub 2} conversion at Waterloo and for NO{sub x} conversion at RTI. Shakedown experiments were completed. In the present quarter, the NO{sub x} removal performance of two additional modified carbon catalysts (MCCII and MCCIII) was studied. MCCII showed NO{sub x} removal efficiency which was similar to that observed for MCCI. However, MCCI was considerably less active for NO{sub x} removal. SO{sub 2} removal experiments with NO present in the feed gas were performed with MCCI. SO{sub 2} removal efficiency was consistently about 98% over each of 10 cycles and was very similar to that observed earlier with no NO present in the feed. Finally, a preliminary economic evaluation of the process was performed and a project review meeting was held. The economic evaluation showed that the Rn-Waterloo process was competitive with SCR/IFGD and other combined SO{sub 2}/NO{sub x}, removal processes.

Gangwal, S.K. (Research Triangle Inst., Research Triangle Park, NC (United States)); Silveston, P.L. (Waterloo Univ., ON (Canada))

1992-07-01

181

The Carbon Cycle and its Role in Climate Change: Activity 3  

NSDL National Science Digital Library

In this activity, learners explore the human influences on the carbon cycle and examine how fossil fuels release carbon. Learners role play as miners, power plant operators, car drivers, and home owners in a city. Learners will act out how each member of society contributes to the carbon cycle and then create a classroom mural depicting the path of carbon. Learners can reflect on this process as well as brainstorm ways to lower their carbon footprints. This activity is the third in a series of three activities that introduce learners to the carbon cycle (see related sources), although it is not mandatory that all three activities are completed as a set.

Management, Us B.; Agency, Us E.; Service, Us F.; Service, Us F.; Administration, National A.; Administration, National A.

2009-01-01

182

Removal of diethyl phthalate from water solution by adsorption, photo-oxidation, ozonation and advanced oxidation process (UV/H?O?, O?/H?O? and O?/activated carbon).  

PubMed

The objective of this work was to compare the effectiveness of conventional technologies (adsorption on activated carbon, AC, and ozonation) and technologies based on advanced oxidation processes, AOPs, (UV/H(2)O(2), O(3)/AC, O(3)/H(2)O(2)) to remove phthalates from aqueous solution (ultrapure water, surface water and wastewater). Diethyl phthalate (DEP) was chosen as a model pollutant because of its high water solubility (1,080 mg/L at 293 K) and toxicity. The activated carbons showed a high adsorption capacity to adsorb DEP in aqueous solution (up to 858 mg/g), besides the adsorption mechanism of DEP on activated carbon is governed by dispersive interactions between ? electrons of its aromatic ring with ? electrons of the carbon graphene planes. The photodegration process showed that the pH solution does not significantly affect the degradation kinetics of DEP and the first-order kinetic model satisfactorily fitted the experimental data. It was observed that the rate of decomposition of DEP with the O(3)/H(2)O(2) and O(3)/AC systems is faster than that with only O(3). The technologies based on AOPs (UV/H(2)O(2), O(3)/H(2)O(2), O(3)/AC) significantly improve the degradation of DEP compared to conventional technologies (O(3), UV). AC adsorption, UV/H(2)O(2), O(3)/H(2)O(2), and O(3)/AC showed a high yield to remove DEP; however, the disadvantage of AC adsorption is its much longer time to reach maximum removal. The best system to treat water (ultrapure and natural) polluted with DEP is the O(3)/AC one since it achieved the highest DEP degradation and TOC removal, as well as the lower water toxicity. PMID:23178761

Medellin-Castillo, Nahum A; Ocampo-Pérez, Raúl; Leyva-Ramos, Roberto; Sanchez-Polo, Manuel; Rivera-Utrilla, José; Méndez-Díaz, José D

2013-01-01

183

Active braze process  

Microsoft Academic Search

Active metal bonding using Cusil (silver-copper) braze alloys is a well established method used at GE Neutron Devices (GEND) for bonding metal to metal, metal to ceramics, and ceramics to ceramics. However, there are many instances in which using a silver alloy for bonding is undesirable (e.g., in vacuum tube envelopes, or where sequential braze steps at different temperatures are

I. L. Levine; R. A. Pike

1990-01-01

184

Adsorption of geosmin and 2-methylisoborneol onto powdered activated carbon at non-equilibrium conditions: influence of NOM and process modelling.  

PubMed

The adsorption of the taste and odour (T&O) compounds geosmin and 2-methylisoborneol (2-MIB) onto powdered activated carbon (PAC) has been studied under conditions which are typical for a drinking water treatment plant that uses reservoir water for drinking water production. The reservoir water as well as the pre-treated water (after flocculation) contains NOM that competes with the trace compounds for the adsorption sites on the carbon surface. Although the DOC concentrations in the reservoir water and in the pre-treated water were different, no differences in the competitive adsorption could be seen. By using two special characterisation methods for NOM (adsorption analysis, LC/OCD) it could be proved that flocculation removes only NOM fractions which are irrelevant for competitive adsorption. Different model approaches were applied to describe the competitive adsorption of the T&O compounds and NOM, the tracer model, the equivalent background compound model, and the simplified equivalent background compound model. All these models are equilibrium models but in practice the contact time in flow-through reactors is typically shorter than the time needed to establish the adsorption equilibrium. In this paper it is demonstrated that the established model approaches can be used to describe competitive adsorption of T&O compounds and NOM also under non-equilibrium conditions. The results of the model applications showed that in particular the simplified equivalent background compound model is a useful tool to determine the PAC dosage required to reduce the T&O compounds below the threshold concentration. PMID:21752419

Zoschke, Kristin; Engel, Christina; Börnick, Hilmar; Worch, Eckhard

2011-10-01

185

A novel carbon-based process for flue gas cleanup  

SciTech Connect

The objective of this project is to demonstrate the preliminary technical and economic feasibility of a novel carbon-based process for removal of at least 95 % SO[sub 2], and at least 75 % NO[sub x] from coal combustion flue gas. In the process, flue gas leaving the electrostatic precipitator (ESP) is passed through a trickle bed of activated carbon catalyst employing a periodic flush of low strength sulfuric acid. The SO[sub 2] is oxidized to SO[sub 3] and removed as medium strength sulfuric acid. The SO[sub 2]-free flue gas is then mixed with NH[sub 3], and the NO[sub x] in the gas is subjected to selective catalytic reduction (SCR) to N[sub 2] over a fixed bed of activated carbon catalyst. In the previous six quarters, detailed project plans were prepared and experimental systems were commissioned. The SO[sub 2] removal factorial experiments with BPL carbon at 21[degrees]C are well underway at Waterloo. A modified carbon catalyst (MCCI) showed up to 99% SO[sub 2] removal in the presence of NO[sub x] over 10 multiple cycles at 80--130[degrees]C and 1400 scc/cc/h. Several catalysts were evaluated for NO[sub x] removal also. Promising modified carbon catalysts (MCCI, II and III) were tested. Some of these catalysts showed the potentialfor over 80% NO[sub x] removal at space velocities as high as 3000 scc/cc/h. Poisoning of NO[sub x] removal efficiency with SO[sub 2] in the feed was also studied. With over 100 ppm SO[sub 2] in feed, NO[sub x]removal efficiency remained steady for several hours. It declined from 79% removal to 66% removal over 24 hours. NO[sub x] removal experiments were performed with 5 different materials and the SO[sub 2] removalactivity of 2 catalysts was tested.

Gangwal, S.K. (Research Triangle Inst., Research Triangle Park, NC (United States)); Silveston, P.L. (Waterloo Univ., ON (Canada))

1993-04-01

186

Studies relevant to the catalytic activation of carbon monoxide  

SciTech Connect

Research activity has included continued mechanistic investigations of the nucleophilic activation of carbon monoxide such as homogeneous catalysis of the water gas shift and key steps in the relevant catalytic cycles. Other investigations of related processes included the application of fast reaction techniques to prepare and to investigate quantitatively reactive organometallic intermediates relevant to the activation of hydrocarbons toward carbonylation and other functionalizations. 8 refs.

Ford, P.C.

1991-09-04

187

A reduced reaction model for carbon CVD\\/CVI processes  

Microsoft Academic Search

Carbon–carbon composites are produced by chemical vapor deposition\\/chemical vapor infiltration (CVD\\/CVI) processes. Models of carbon–carbon composite production processes will help reduce production costs. Reliable process models must, however, include details of the gas phase kinetics in order to identify optimal conditions. We have combined detailed gas phase kinetics, surface kinetics, and a pore closure model to predict pore geometry changes

Narayana Birakayala; Edward A Evans

2002-01-01

188

Use of granulated activated carbon at the Oak Ridge Y-12 Plant Central Pollution Control facility.  

National Technical Information Service (NTIS)

There are few industrial waste treatment processes that do not include some form of fixed bed activated carbon adsorption for removal of organic contaminants. This processes is especially important when the effluent of a treatment process is discharged to...

J. Gilpin

1991-01-01

189

DEVELOPMENT OF ACTIVATED CARBONS FROM COAL COMBUSTION BY-PRODUCTS  

SciTech Connect

The increasing role of coal as a source of energy in the 21st century will demand environmental and cost-effective strategies for the use of coal combustion by-products (CCBPs), mainly unburned carbon in fly ash. Unburned carbon is nowadays regarded as a waste product and its fate is mainly disposal, due to the present lack of efficient routes for its utilization. However, unburned carbon is a potential precursor for the production of adsorbent carbons, since it has gone through a devolatilization process while in the combustor, and therefore, only requires to be activated. Accordingly, this report evaluates and compares several routes for the production of activated carbons from unburned carbon in fly ash, including physical and chemical activation methods. During the present reporting period (June 30, 2001-June 29, 2002), additional characterization work was conducted under Task 1 ''Procurement and characterization of CCBPs''. The suite collected includes samples from pulverized utility boilers, a utility cyclone unit equipped with a beneficiation technology, a stoker, and a fluidized bed combustor. Proximate, ultimate, and petrographic analyses of the fly ash samples previously collected were measured. Furthermore, the surface areas of the samples assembled were characterized by N{sub 2} adsorption isotherms at 77 K. The proximate analyses showed that all the samples had very low moisture contents (0.17 to 3.39 wt%), while volatile matter contents of the samples varied between 0.45 to 24.8 wt%. The ultimate analyses of all the fly ash samples showed that they contained primarily carbon, while the hydrogen contents of all the samples were very low. In addition, during the current reporting period, also Task 2 ''Development of activated carbons'' and Task 3 ''Characterization of activated carbons'' were continued.

Prof. Harold H. Schobert; Dr. M. Mercedes Maroto-Valer; Ms. Zhe Lu

2002-09-27

190

TWO-STAGE GRANULAR ACTIVATED CARBON TREATMENT  

EPA Science Inventory

Two 6.3 l/sec (0.15 mgd), two-stage, packed-bed, downflow granular activated carbon pilot plants were operated continuously for 33 months using unfiltered and unchlorinated activated sludge plant effluent. The main objective of the study was to compare the performance of granular...

191

Structural and adsorptive properties of activated carbons prepared by carbonization and activation of resins  

Microsoft Academic Search

Four activated carbons (S1–S4) possessing different structural characteristics were prepared by carbonization of commercial resins (used for ion exchange) and subsequent activation. Their textural parameters were determined on the basis of nitrogen adsorption–desorption at 77.4 K, analyzed by applying several local and overall adsorption isotherm equations. The nature of carbon surface functionalities was analyzed by FTIR spectroscopy. The GC and

R. Leboda; J. Skubiszewska-Zi?ba; W. Tomaszewski; V. M. Gun'ko

2003-01-01

192

JV Task 90 - Activated Carbon Production from North Dakota Lignite  

Microsoft Academic Search

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

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

2008-01-01

193

Comparison of Toluene Adsorption Among Granular Activated Carbon and Different Types of Activated Carbon Fibers (ACFs)  

Microsoft Academic Search

Activated carbon fiber (ACF) has been demonstrated to be a good adsorbent for the removal of organic vapors in air. Some ACF has a comparable or larger surface area and higher adsorption capacity when compared with granular activated carbon (GAC) commonly used in respiratory protection devices. ACF is an attractive alternative adsorbent to GAC because of its ease of handling,

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

2011-01-01

194

Electrochemical storage of energy in acrylic activated carbon fibres and activated carbons made from industrial residues  

Microsoft Academic Search

In this work the application as electrochemical capacitors of novel materials, never tested before for this propose, were investigated using classic cyclic voltammetry, chrono potentiometry, chrono amperometry and electrochemical impedance spectroscopy. The tested materials were prepared in our laboratory: a) acrylic activated carbon fibres (ACF) (samples F920, F932, F993) produced from a commercial acrylic fiber by carbon dioxide activation at

J. Valente Nabais; J. Teixeira; I. Almeida; P. J. M. Carrott; M. M. L. R. Carrott; Rua Romão Ramalho

195

Microporous Activated Carbons Prepared from Palm Shell by Thermal Activation and Their Application to Sulfur Dioxide Adsorption  

Microsoft Academic Search

Textural characterization of activated carbons prepared from palm shell by thermal activation with carbon dioxide (CO2) gas is reported in this paper. Palm shell (endocarp) is an abundant agricultural solid waste from palm-oil processing mills in many tropical countries such as Malaysia, Indonesia, and Thailand. The effects of activation temperature on the textural properties of the palm-shell activated carbons, namely

Jia Guo; Aik Chong Lua

2002-01-01

196

Cyclic process for producing methane from carbon monoxide with heat removal  

DOEpatents

Carbon monoxide-containing gas streams are converted to methane by a cyclic, essentially two-step process in which said carbon monoxide is disproportionated to form carbon dioxide and active surface carbon deposited on the surface of a catalyst, and said carbon is reacted with steam to form product methane and by-product carbon dioxide. The exothermic heat of reaction generated in each step is effectively removed during each complete cycle so as to avoid a build up of heat from cycle-to-cycle, with particularly advantageous techniques being employed for fixed bed, tubular and fluidized bed reactor operations.

Frost, Albert C. (Congers, NY); Yang, Chang-lee (Spring Valley, NY)

1982-01-01

197

SUPERCRITICAL FLUID REGENERATION OF ACTIVATED CARBON FOR ADSORPTION OF PESTICIDES  

EPA Science Inventory

The report describes the development of a new process for regenerating activated carbon, using supercritical CO2 as a desorbent. Supercritical CO2 in the range of 30-250 C and at pressures > 80 atm. is a good solvent for organics. A series of pesticides was tested for treatment b...

198

USE OF GRAPE STALK TO OBTAIN ACTIVATED CARBON  

Microsoft Academic Search

Grape stalk is a common agricultural waste from Cuyo Region-Argentina, which is available in large quantities and at low prices. It is the woody part of the grape cluster, represents about 4% of its weight and it is discarded at the beginning of the wine making process. As any carbonaceous material, grape stalk can be used to obtain activated carbon.

A. Amaya; N. Tancredi; F. Sardella; E. Aguilar; C. Deiana; H. Silva

199

Activated Carbon Open Circuit Potential Shifts in Aqueous Solutions  

Microsoft Academic Search

Interaction of certain organic compounds with activated carbon and its effect on the carbon open circuit potentials were studied. It was shown that shifts in open circuit potentials depended on the filling of the activated carbon surface. Whereas adsorption of the investigated compounds on the carbon led to positive potential shifts, their elimination (desorption) from carbon surface led to shifts

Mikhail M. Goldin; Gary Blanchard; Alexander Volkov; Mogely Khubutiya; Vladimir Kolesnikov; Anatoly Evseev; Mark Goldin

2007-01-01

200

Reprocessing of used tires into activated carbon and other products  

Microsoft Academic Search

Landfilling used tires which are generated each year in the US is increasingly becoming an unacceptable solution. A better approach, from an environmental and economic standpoint, is to thermally reprocess the tires into valuable products such as activated carbon, other solid carbon forms (carbon black, graphite, and carbon fibers), and liquid fuels. In this study, high surface area activated carbons

Hsisheng Teng; Michael A. Serio; Marek A. Wojtowicz; Rosemary Bassilakis; Peter R. Solomon

1995-01-01

201

Production Scale-Up or Activated Carbons for Ultracapacitors  

SciTech Connect

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.

Dr. Steven D. Dietz

2007-01-10

202

Removal of phenol from aqueous solution using carbonized Terminalia chebula-activated carbon: process parametric optimization using conventional method and Taguchi's experimental design, adsorption kinetic, equilibrium and thermodynamic study  

NASA Astrophysics Data System (ADS)

In the present paper, the phenol removal from wastewater was investigated using agri-based adsorbent: Terminalia chebula-activated carbon (TCAC) produced by carbonization of Terminalia chebula (TC) in air-controlled atmosphere at 600 °C for 4 h. The surface area of TCAC was measured as 364 m2/g using BET method. The surface characteristic of TCAC was analyzed based on the value of point of zero charge. The effect of parameters such as TCAC dosage, pH, initial concentration of phenol, time of contact and temperature on the sorption of phenol by TCAC was investigated using conventional method and Taguchi experimental design. The total adsorption capacity of phenol was obtained as 36.77 mg/g using Langmuir model at the temperature of 30 °C at pH = 5.5. The maximum removal of phenol (294.86 mg/g) was obtained using Taguchi's method. The equilibrium study of phenol on TCAC showed that experimental data fitted well to R-P model. The results also showed that kinetic data were followed more closely the pseudo-first-order model. The results of thermodynamic study showed that the adsorption of phenol on TCAC was spontaneous and an exothermic in nature.

Khare, Prateek; Kumar, Arvind

2012-12-01

203

A novel activated carbon for supercapacitors  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer A novel activated carbon was prepared from phenol-melamine-formaldehyde resin. Black-Right-Pointing-Pointer The carbon has large surface area with microporous, and high heteroatom content. Black-Right-Pointing-Pointer Heteroatom-containing functional groups can improve the pseudo-capacitance. Black-Right-Pointing-Pointer Physical and chemical properties lead to the good electrochemical properties. -- Abstract: A novel activated carbon has been prepared by simple carbonization and activation of phenol-melamine-formaldehyde resin which is synthesized by the condensation polymerization method. The morphology, thermal stability, surface area, elemental composition and surface chemical composition of samples have been investigated by scanning electron microscope, thermogravimetry and differential thermal analysis, Brunauer-Emmett-Teller measurement, elemental analysis and X-ray photoelectron spectroscopy, respectively. Electrochemical properties have been studied by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements in 6 mol L{sup -1} potassium hydroxide. The activated carbon shows good capacitive behavior and the specific capacitance is up to 210 F g{sup -1}, which indicates that it may be a promising candidate for supercapacitors.

Shen, Haijie [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China)] [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China); Liu, Enhui, E-mail: liuenhui99@sina.com.cn [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China)] [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China); Xiang, Xiaoxia; Huang, Zhengzheng; Tian, Yingying; Wu, Yuhu; Wu, Zhilian; Xie, Hui [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China)] [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China)

2012-03-15

204

Carbon Dioxide Capture with Amine-Grafted Activated Carbon  

Microsoft Academic Search

There are several possible methods by which amine groups can be grafted on the surface of activated carbon (AC) to improve\\u000a their capacity for CO2 adsorption. Ethylenediamine and diethylenetriamine were selected as amino compounds for anchoring on the surface of an oxidized\\u000a AC. Oxidation of AC was carried out by concentrated nitric acid. For each amino compound, two “in-solvent” and

Amirhossein Houshmand; Wan Mohd Ashri Wan Daud; Min-Gyu Lee; Mohammad Saleh Shafeeyan

205

Inorganic Carbon Cycling and the Biogeochemical Processes in Hudson Bay  

NASA Astrophysics Data System (ADS)

Coastal seas, like Hudson Bay, are biogeochemically active areas with high primary productivity. High productivity can be expected to lead to fractionation of 13C/12C creating depletion of 12C isotope of Dissolved Inorganic Carbon (12CDIC) in the surface and enrichment of 12CDIC in deeper waters. The increase of anthropogenic CO2 concentration can have drastic impacts on the biogeochemical properties of the ocean. Since the Arctic and coastal seas are primarily sensitive to these changes, assessing the carbon cycle of this area is very important for future studies. We present the carbon cycle and related data from the Arctic Net 2010 Cruise. We investigate and assess the processes governing the carbon cycle over the entire water column of Hudson Bay. We find that the deep waters of Hudson Bay are Pacifically derived and do not interact with Atlantic waters beyond the mouth of the Bay. River input greatly affect the waters of Hudson Bay. Also, the longer residence time of the deep Hudson Bay waters allows the accumulation of products due to various biogeochemical and physical processes. These include respiration of organic matter, which causes greater DIC and lower del13C values at depth, and brine formation, which increases salinity, DIC and alkalinity. The eastern side of Hudson is observed to have greater DIC concentrations and is isotopically lighter in del13C than the western side.

Pengelly, Leah; Thomas, Helmuth; Burt, William; Papakyriakou, Tim; Miller, Lisa

2014-05-01

206

Catalytic oxidation of TNT by activated carbon  

Microsoft Academic Search

Activated carbon can remove 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitrobenzene (TNB) from aqueous solution and promote oxidation of TNT. After equilibrating a 0.35 mM TNT solution with activated carbon (0.2–1% w\\/v), HPLC and GC\\/MS analysis confirmed the presence of 2,4,6-trinitrobenzaldehyde (TNBAld) and 2,4,6-trinitrobenzene (TNB), and provided strong evidence supporting 2,4,6-trinitrobenzyl alcohol (TNBAlc) as an intermediate of TNT oxidation. After 6 d, TNT

G. K. Vasilyeva; V. D. Kreslavski; P. J. Shea

2002-01-01

207

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

DOEpatents

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.

Srinivasachar, Srivats (Sturbridge, MA); Benson, Steven (Grand Forks, ND); Crocker, Charlene (Newfolden, MN); Mackenzie, Jill (Carmel, IN)

2011-07-19

208

Adsorption of naphthenic acids on high surface area activated carbons.  

PubMed

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

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

2014-07-01

209

Activated carbon monoliths for methane storage  

NASA Astrophysics Data System (ADS)

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.

Chada, Nagaraju; Romanos, Jimmy; Hilton, Ramsey; Suppes, Galen; Burress, Jacob; Pfeifer, Peter

2012-02-01

210

The Properties of Activated Carbon Made from Waste Newsprint Paper  

Microsoft Academic Search

Activated carbon is a porous material made by activation of carbon materials, such as coal, by steam or carbon dioxide gas to form numerous micropores on the surface which gives the material high adsorption characteristics and it is widely used as a purifier for water and air. In this research, to develop a new use for waste paper, activated carbon

Masahiro Shimada; Hisashi Hamabe; Takahiko Iida; Kensuke Kawarada; Takayuki Okayama

1999-01-01

211

Production of activated carbon from a new precursor: Molasses  

Microsoft Academic Search

Activated carbon has been prepared from molasses, a natural precursor of vegetable origin resulting from the sugar industry in Morocco. The preparation of the activated carbon from the molasses has been carried out by impregnation of the precursor with sulfuric acid, followed by carbonization. The adsorption capacity, the BET surface area, and the pore volume of the activated carbon were

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

2005-01-01

212

Porous properties of activated carbons from waste newspaper prepared by chemical and physical activation  

Microsoft Academic Search

Activated carbons were prepared from old newspaper and paper prepared from simulated paper sludge by chemical activation using various alkali carbonates and hydroxides as activating reagents and also by physical activation using steam. In the chemical activation, the influence of oxidation, carbonization, and activation on the porous properties of the resulting activated carbons was investigated. The specific surface areas (SBET)

Kiyoshi Okada; Nobuo Yamamoto; Yoshikazu Kameshima; Atsuo Yasumori

2003-01-01

213

Optimum manufacturing conditions of activated carbon fiber absorbents. II. Effect of carbonization and activation conditions  

Microsoft Academic Search

In this paper, viscose rayon-based knitted fabrics were utilized as the precursor to produce activated carbon fiber absorbents\\u000a (ACFA). The effects of carbonization and activation conditions on characteristics (ACFA) were examined. Experimental results\\u000a revealed that increasing the flow rate of environmental gas N2 and steam activator used in conjunction and decreasing the production rate of ACFA can obtain better pore

Ching-Iuan Su; Ching-Luh Wang

2007-01-01

214

A novel carbon-based process for flue gas cleanup  

SciTech Connect

The objective of this project is to demonstrate the preliminary technical and economic feasibility of a novel carbon-based process for removal of at least 95% SO{sub 2} and at least 75% NO{sub x} coal combustion flue gas. In the process, flue gas leaving the electrostatic precipitator (ESP) is passed through a trickle bed of achieved carbon catalyst employing a periodic flush of low strength sulfuric acid. The SO{sub 2} is oxidized to SO{sub 3} and removed as medium strength sulfuric acid. The SO{sub 2}-free flue gas is then mixed with NH{sub 3}, and the NO{sub x} in the gas is subjected to selective catalytic reduction (SCR) to N{sub 2} over a fixed bed of activated carbon catalyst. The experimental work is divided between Research Triangle Institute (RTI) and the University of Waterloo (Waterloo). RTI will conduct the NO{sub x} removal studies, whereas Waterloo will conduct the SO{sub 2} removal studies. The ultimate goal of the project is to demonstrate that the process can be reduce the cost of electricity by 20% over conventional SCR/flue gas desulfurization (FGD) processes. In the present quarter, the continuous SO{sub 2} analyzer system at Waterloo was completed. The SO{sub 2} removal factorial experiments were begun Waterloo with the BPL carbon at 21{degrees}C. Also, SO{sub 2} removal was tested on two catalyst at RTI at 80{degrees}C. NO{sub x} conversion was tested on a variety of catalysts at RTI. It was shown that the BPL carbon could remove over 95% SO{sub 2} at 21{degrees}C but would required several beds at space velocity in each bed of abut 1,500 scc/(cc{center dot}h) to reduce SO{sub 2} from 2,500 ppm to 100 ppm. A modified carbon catalyst tested at RTI showed 99% SO{sub 2} removal at 80{degrees}C at 1,400 scc/(cc{center dot}h). Also, it was possible to produce nearly 9 normal H{sub 2}SO{sub 4} by periodic flushing of this catalyst. The modified carbon catalyst also demonstrated removal of more than 80% NO{sub x}. 7 refs., 7 figs., 4 tabs.

Gangwal, S.K. (Research Triangle Inst., Research Triangle Park, NC (United States)); Silveston, P.L. (Waterloo Univ., ON (Canada))

1992-04-01

215

A novel carbon-based process for flue gas cleanup  

SciTech Connect

The objective of this project is to demonstrate the preliminary technical and economic feasibility of a novel carbon-based process for removal of at least 95% S0[sub 2] and at least 75 % NO[sub x], from coal combustion flue gas. In the process, flue gas leaving the electrostatic precipitator (ESP) is passed through a trickle bed of activated carbon catalyst employing a periodic flush of low strength sulfuric acid. The S0[sub 2] is oxidized to S0[sub 3] and removed as medium strength sulfuric acid. The S0[sub 2]-free flue gas is then mixed with NH[sub 3], and the NO[sub x] in the gas is subjected to selective catalytic reduction (SCR) to N[sub 2] over a fixed bed of activated carbon catalyst. In the previous four quarters, a detailed project management plan was prepared describing the experimental setup, work plan, and test plan. The experimental system was completed for SO[sub 2] conversion at Waterloo and for NO[sub x] conversion at Research Triangle Institute. Shakedown experiments were completed. The NO[sub x] removal performance of two additional modified carbon catalysts (MCCII and MCCIII) was studied. MCCII showed NO[sub 2] removal efficiency which was similar to that observed for MCCI. However, MCCIII was considerably less active for NO[sub x] removal. In the present quarter, further tests of MCCI were performed for SO[sub 2] removal with NO in the feed gas, except the reactor was operated at 130[degrees]C (instead of 80[degrees]C during previous tests). Tests were also performed with MCCII for NO removal with nominally 100 ppm SO[sub 2] in the feed gas.

Gangwal, S.K. (Research Triangle Inst., Research Triangle Park, NC (United States)); Silveston, P.L. (Waterloo Univ., ON (Canada))

1992-10-01

216

Atypical Hydrogen Uptake on Chemically Activated, Ultramicroporous Carbon  

SciTech Connect

Hydrogen adsorption at near-ambient temperatures on ultramicroporous carbon (UMC), derived through secondary chemical activation from a wood-based activated carbon was studied using volumetric and gravimetric methods. The results showed that physisorption is accompanied by a process of different nature that causes slow uptake at high pressures and hysteresis on desorption. In combination, this results in unusually high levels of hydrogen uptake at near-ambient temperatures and pressures (e.g. up to 0.8 wt % at 25 oC and 2 MPa). The heat of adsorption corresponding to the slow process leading to high uptake (17 20 kJ/mol) is higher than usually reported for carbon materials, but the adsorption kinetics is slow, and the isotherms exhibit pronounced hysteresis. These unusual properties were attributed to contributions from polarization-enhanced physisorption caused by traces of alkali metals residual from chemical activation. The results support the hypothesis that polarization-induced physisorption in high surface area carbons modified with traces of alkali metal ions is an alternate route for increasing the hydrogen storage capacity of carbon adsorbents.

Bhat, Vinay V [ORNL; Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Baker, Frederick S [ORNL

2010-01-01

217

DEVELOPMENT OF ACTIVATED CARBONS FROM COAL COMBUSTION BY-PRODUCTS  

SciTech Connect

The implementation of increasingly stringent Clean Air Act Regulations by the coal utility industry has resulted in an increase in the concentration of unburned carbon in coal combustion fly ash. In 1999, around 6 million tons of unburned carbon were disposed in the US, due to the present lack of efficient routes for its utilization. However, unburned carbon is a potential precursor for the production of adsorbent carbons, since it has gone through a devolatilization process while in the combustor, and therefore, only requires to be activated. Accordingly, this report evaluates and compares several routes for the production of activated carbons from unburned carbon, including physical activation with steam or CO{sub 2}, and chemical activation using KOH pretreatment. During the present reporting period (June 30, 2000--June 29, 2001), Task 1 ''Procurement and characterization of CCBPs'' was concluded, including samples from pulverized utility boilers, a utility cyclone unit equipped with a beneficiation technology, a suspension-fired research boiler, and a class C fly ash. The characterization studies showed that the samples collected have significantly different carbon contents, as determined by the ASTM C114 procedure, with the sample from the cyclone unit containing the highest carbon content (LOI of {approx} 80%), since this unit has been retrofitted with a technology to separate the unburned carbon from the fly ash. The porosity of the samples assembled was characterized by N{sub 2} adsorption isotherms at 77K. The surface areas of the class F fly ash samples from pulverized coal combustors are between 30-40 m{sup 2}/g, while the samples from the suspension-fired research boiler had surface area around 115 m{sup 2}/g. As expected, the surface areas of the class C ash is much higher than that of the class F ashes, with values up to 390 m{sup 2}/g. In addition, during the current reporting period, also Task 2 ''Development of activated carbons'' and Task 3 ''Characterization of activated carbons'' were continued.

Prof. Harold H. Schobert; Dr. M. Mercedes Maroto-Valer; Ms. Zhe Lu

2001-09-29

218

Adsorption of Tin Using Granular Activated Carbon  

Microsoft Academic Search

Adsorption studies for removal of tin from the aqueous phase using granular activated carbon (GAC) and characterization of GAC were carried out. Particle size, proximate, ash, and ultimate analyses were carried out for the physiochemical characteristics of GAC. Thermogravimetric analysis was also done both in ambient and nitrogen atmospheres to see the effect of temperature on GAC stability. Morphological characteristics

Kailas L. WASEWAR; Shiv KUMAR; B. PRASAD

2009-01-01

219

Granular Activated Carbon Filter-Adsorber Systems  

Microsoft Academic Search

The design, operation, and performance of granular activated carbon (GAC) filter-adsorbers were documented and potential problems were identified by means of a survey of operating plants and a review of the literature. It was found that GAC as a total or partial replacement for sand is as effective as conventional filtration media for removing turbidity, provided an appropriate medium size

Sandra L. Graese; Vernon L. Snoeyink; Ramon G. Lee

1987-01-01

220

OPTIMIZING GAC (GRANULAR ACTIVATED CARBON) SYSTEMS  

EPA Science Inventory

Granular activated carbon (GAC) is an effective technique for removing synthetic organics from both ground and surface waters. Questions have been raised, however, over the cost of using GAC in this manner. To provide insight into these cost issues, the Drinking Water Research Di...

221

EPA'S RESEARCH PROGRAM IN GRANULAR ACTIVATED CARBON  

EPA Science Inventory

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

222

USING POWDERED ACTIVATED CARBON: A CRITICAL REVIEW  

EPA Science Inventory

Because the performance of powdered activated carbon (PAC) for uses other than taste and odor control is poorly documented, the purpose of this article is to critically review uses that have been reported and to analyze means of employing PAC more efficiently. The extent of adsor...

223

MODELING MERCURY CONTROL WITH POWDERED ACTIVATED CARBON  

EPA Science Inventory

The paper presents a mathematical model of total mercury removed from the flue gas at coal-fired plants equipped with powdered activated carbon (PAC) injection for Mercury control. The developed algorithms account for mercury removal by both existing equipment and an added PAC in...

224

ACTIVATED CARBON TREATMENT OF KRAFT BLEACHING EFFLUENTS  

EPA Science Inventory

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

225

Rate of Thermal Regeneration of Activated Carbon.  

National Technical Information Service (NTIS)

Activated carbon was reacted with steam at varying gas flow rates, steam concentrations and temperatures. The reaction kinetics va ed with the steam concentration to the 0.58 power and had an activatio ergy of 63.6 kcal/g mole. The reaction rate was found...

H. E. Klei D. W. Sundstrom

1974-01-01

226

USING POWDERED ACTIVATED CARBON: A CRITICAL REVIEW  

EPA Science Inventory

Because the performance of powdered activated carbon (PAC) for uses other than taste and odor control is poorly documented, the purpose of this article is to critically review uses that have been reported (i.e., pesticides and herbicides, synthetic organic chemicals, and trihalom...

227

PRODUCTION OF ACTIVATED CARBON FROM BAMBOO USING CHEMICAL AND STEAM ACTIVATIONS  

Microsoft Academic Search

Bamboo is a natural resource in Malaysia as it takes only several months to grow and be ready for harvesting. Primary processing of bamboo for conversion into specified products generates a large amount of residues is generated. This residue could be effectively converted into value-added products such as activated carbon and charcoal. There are two phases in this progress activity

E. Puad Mahanim; J. Rafidah

228

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

SciTech Connect

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

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

1999-11-01

229

Carbon-Based Supercapacitors Produced by Activation of Graphene  

NASA Astrophysics Data System (ADS)

Supercapacitors, also called ultracapacitors or electrochemical capacitors, store electrical charge on high-surface-area conducting materials. Their widespread use is limited by their low energy storage density and relatively high effective series resistance. Using chemical activation of exfoliated graphite oxide, we synthesized a porous carbon with a Brunauer-Emmett-Teller surface area of up to 3100 square meters per gram, a high electrical conductivity, and a low oxygen and hydrogen content. This sp2-bonded carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form primarily 0.6- to 5-nanometer-width pores. Two-electrode supercapacitor cells constructed with this carbon yielded high values of gravimetric capacitance and energy density with organic and ionic liquid electrolytes. The processes used to make this carbon are readily scalable to industrial levels.

Zhu, Yanwu; Murali, Shanthi; Stoller, Meryl D.; Ganesh, K. J.; Cai, Weiwei; Ferreira, Paulo J.; Pirkle, Adam; Wallace, Robert M.; Cychosz, Katie A.; Thommes, Matthias; Su, Dong; Stach, Eric A.; Ruoff, Rodney S.

2011-06-01

230

Processing and characterization of monolithic carbon structures based on wood fiberboards  

NASA Astrophysics Data System (ADS)

The structure and properties of monolithic carbonized medium-density fiberboards were studied to expand the capabilities of carbonized wood processing. Medium-density fiberboard (MDF) has a more uniform structure than wood, which was investigated in earlier studies for monolithic carbon structures. The uniform structure of medium density fiberboard (MDF) allowed for a reduction in thermal processing time from 4.5 days for wood carbonization to 1 day for MDF carbonization. Key physical properties of carbonized MDF (c-MDF) were determined for potential applications, such as battery electrodes, fuel cell separators and activated carbon filters. X-ray diffraction (XRD) was used to characterize the growth of large turbostratic crystallites and large graphene sheets during the carbonization process. A novel x-ray diffraction method using monolithic pieces of c-MDF was used to correlate the dimensional changes occurring during the carbonization process with the growth of large turbostratic crystallites. The insights gained from the XRD investigation of c-MDF were used to develop a quasipercolation model, which describes the microstructural evolution of hard carbons. This quasipercolation model explained the observed changes in bulk density, dimension, helium density and electrical conductivity of c-MDF. The model also explained how nanopores form in activated carbon materials. The mechanical and electrical properties of carbonized MDF were measured using ASTM 4-point bending and 4-point electrical conductivity techniques. The elastic modulus was shown to vary from 1.5 to 4.5 GPa for the carbonization temperature range of 600°C to 1000°C. The electrical resistivity varied by seven orders of magnitude from 600°C to 1400°C. An open foam model was used to approximate the mechanical and electrical properties of the hard carbon material in the porous c-MDF. Large structural activated carbons were made by physical activation of c-MDF in carbon dioxide. A low activation temperature was used to uniformly activate the porous c-MDF structure. Activated carbonized MDF achieved a BET surface area of approximately 1000 m2/g. Mechanical properties of activated c-MDF showed that these materials can be activated without significantly reducing their mechanical integrity.

Kercher, Andrew Keith

231

Steam-activated carbons from a bituminous coal in a continuous multistage fluidized bed pilot plant  

Microsoft Academic Search

A vertical three-stage fluidized bed pilot plant, with downcomers, was designed and built in order to study the continuous process of the production of activated carbons from a high-volatile bituminous coal from the Puertollano basin (Spain), by steam activation. The pilot plant can operate with a production of up to 40 kg per day. Very good activated carbons were produced

I. Martín-Gullón; M. Asensio; A. Marcilla

1996-01-01

232

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

Microsoft Academic Search

Activated carbon is produced from coconut shell char using steam or carbon dioxide as the reacting gas in a 100 mm diameter fluidized bed reactor. The effect of process parameters such as reaction time, fluidizing velocity, particle size, static bed height, temperature of activation, fluidizing medium, and solid raw material on activation is studied. The product is characterized by determination

P. M. Satya Sai; Jaleel Ahmed; K. Krishnaiah

1997-01-01

233

PRODUCTION OF ACTIVATED CARBON FROM COAL CHARS USING MICROWAVE ENERGY  

Microsoft Academic Search

The microwave induced reaction of carbon with carbon dioxide has been investigated as a method of production of activated carbon using coal char. Factors which control the carbon-carbon dioxide reaction in a microwave environment were also studied.Results indicate that the reaction rate is primarily controlled by the electric field strength. The reaction rate or conversion follows an Arrhenius type relationship

LOREN M. NORMAN; C. Y. CHA

1995-01-01

234

A novel carbon-based process for flue gas cleanup  

SciTech Connect

The objective of this project is to demonstrate the preliminary technical and economic feasibility of a novel carbon-based process for removal of at least 95% SO{sub 2} and at least 75% NO{sub x} from coal combustion flue gas. In the process, flue gas leaving the electrostatic precipitator (ESP) is passed through a trickle bed of activated carbon catalyst employing a periodic flush of low strength sulfuric acid. The SO{sub 2} is oxidized to SO{sub 3} and removed as medium strength sulfuric acid. The SO{sub 2}-free flue gas is then mixed with NH{sub 3}, and the NO{sub x} in the gas is subjected to selective catalytic reduction (SCR) to N{sub 2} over a fixed-bed of activated carbon catalyst. The project is being carried over 14 months (June 4, 1991 to July 31, 1992). The experimental work is divided between Research Triangle Institute (RTI) and the University of Waterloo (Waterloo). RTI will conduct the NO{sub x} removal studies, whereas Waterloo will conduct the SO{sub 2} removal studies. The ultimate goal of the project is to demonstrate that the process can reduce the cost of electricity by 20% over conventional SCR/flue gas desulfurization (FGD) processes. In the present quarter, a detailed project management plan was prepared describing the experimental set-up, work plan and test plan. The experimental equipment is being constructed and is nearly complete with shakedown experiments scheduled to begin on or about November 1, 1991. Also, a paper was prepared and presented for the Seventh Annual Contractor's Conference. The first set of experiments will be completed in the next quarter. 7 refs., 5 figs., 4 tabs.

Not Available

1991-10-01

235

Simulation of the carbonization stage in the production of activated carbons from wood wastes  

Microsoft Academic Search

A mathematical model of the stage of carbonization of the wood batch was developed, and physicochemical constants of the carbonization reaction were determined. The simulation of the carbonization stage was carried out with the use of a computer, and the parameters of carbonization in the tubular element of a small-capacity commercial reactor for production of activated carbon from plant wastes

Samoilov

1994-01-01

236

Microbial processing of carbon in hydrothermal systems (Invited)  

NASA Astrophysics Data System (ADS)

Microorganisms are known to be active in hydrothermal systems. They catalyze reactions that consume and produce carbon compounds as a result of their efforts to gain energy, grow and replace biomass. However, the rates of these processes, as well as the size of the active component of microbial populations, are poorly constrained in hydrothermal environments. In order to better characterize biogeochemical processes in these settings, a quantitative relationship between rates of microbial catalysis, energy supply and demand and population size is presented. Within this formulation, rates of biomass change are determined as a function of the proportion of catabolic power that is converted into biomass - either new microorganisms or the replacement of existing cell components - and the amount of energy that is required to synthesize biomass. The constraints that hydrothermal conditions place on power supply and demand are explicitly taken into account. The chemical composition, including the concentrations of organic compounds, of diffuse and focused flow hydrothermal fluids, hydrothermally influenced sediment pore water and fluids from the oceanic lithosphere are used in conjunction with cell count data and the model described above to constrain the rates of microbial processes that influence the carbon cycle in the Juan de Fuca hydrothermal system.

LaRowe, D.; Amend, J. P.

2013-12-01

237

Selective activation of carbon-carbon bonds next to a carbonyl group  

NASA Astrophysics Data System (ADS)

ORGANOMETALLIC complexes are used to effect a wide range of catalytic transformations in organic synthesis, such as the activation of C-H bonds1,2. Carbon-carbon bonds, however, are generally unreactive towards transition metals under homogeneous conditions. C-C bond activation by a process of oxidative addition to soluble transition-metal complexes has been limited mostly to stoichiometric (not catalytic) reactions1,3-7,18, to highly strained substrates such as cyclopropane and cubane1,8-11 or to chelating ketones19. Here we present a synthetically useful process of selective C-C bond activation in which the C-C bond adjacent to a carbonyl group is opened by insertion of a soluble rhodium(I) complex. The resulting organometallic intermediate can be transformed to a variety of products in a way that regenerates the rhodium complex. We anticipate that this catalytic scheme will have considerable utility in organic synthesis.

Murakami, Masahiro; Amii, Hideki; Ito, Yoshihiko

1994-08-01

238

Importance of structural and chemical heterogeneity of activated carbon surfaces for adsorption of dibenzothiophene  

SciTech Connect

The performance of various activated carbons obtained from different carbon precursors (i.e., plastic waste, coal, and wood) as adsorbents for the desulfurization of liquid hydrocarbon fuels was evaluated. To increase surface heterogeneity, the carbon surface was modified by oxidation with ammonium persulfate. The results showed the importance of activated carbon pore sizes and surface chemistry for the adsorption of dibenzothiophene (DBT) from liquid phase. Adsorption of DBT on activated carbons is governed by two types of contributions: physical and chemical interactions. The former include dispersive interactions in the microporous network of the carbons. While the volume of micropores governs the amount physisorbed, mesopores control the kinetics of the process. On the other hand, introduction of surface functional groups enhances the performance of the activated carbons as a result of specific interactions between the acidic centers of the carbon and the basic structure of DBT molecule as well as sulfur-sulfur interactions.

Ania, C.O.; Bandosz, T.J. [CUNY City College, New York, NY (United States). Dept. of Chemistry

2005-08-16

239

Optimization of the Preparation Conditions for Activated Carbons from Sugarcane Bagasse: An Agricultural Waste  

Microsoft Academic Search

The low-cost activated carbon was prepared from sugarcane bagasse, an agricultural waste material, by chemical activation with different reagents. Orthogonal experimental design was applied to study the influence of activation temperature, activation time and chemical ratio of reagents to sugarcane bagasse on the chemical activation process of sugarcane bagasse. The optimal activated carbon was obtained using impregnation ratio of 0.39-0.78%

Zelong Xu; Yinian Zhu; Meina Liang; Hua Zhang; Huili Liu

2011-01-01

240

Production of Activated Carbon from Date Stones by Using Zinc Chloride  

Microsoft Academic Search

Production of activated carbon from date stones by chemical activation with zinc chloride (ZnCl2) was experimentally investigated using a laboratory-scale fluidized-bed reactor. The effects of process variables, such as activation time, activation temperature, impregnation ratio, and particle size, on the production and quality of activated carbon were measured in terms of adsorptive capacity by iodine number test. An activation time

F. A. H. Al-Qaessi

2010-01-01

241

Fabrication of novel micro-nano carbonous composites based on self-made hollow activated carbon fibers  

NASA Astrophysics Data System (ADS)

The hollow activated carbon fibers (HACF) were prepared by using commercial polypropylene hollow fiber (PPHF) as the template, and phenol-formaldehyde resin (PF) as carbon precursors. Final HACF was formed through the thermal decomposition and carbonization of PF at 700 °C under the nitrogen atmosphere, and activation at 800 °C with carbon dioxide as the activating agent, consecutively. Then, carbon nanotubes (CNTs) were grown by chemical vapor deposition (CVD) techniques using the as-grown porous HACF as substrate. The growth process was achieved by pyrolyzing ethanol steam at 700 °C using nickel as catalyst. Finally, CNTs was grown successfully on the substrate, and a novel tree-like micro-nano carbonous structure CNTs/HACF was fabricated. The as-grown HACF and micro-nano CNTs/HACF were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TG), respectively. Moreover, the formation mechanisms were also discussed.

Kong, Yuxia; Qiu, Tingting; Qiu, Jun

2013-01-01

242

Production of Activated Carbons from Pyrolysis of Waste Tires Impregnated with Potassium Hydroxide  

Microsoft Academic Search

Activated carbons were produced from waste tires using a chemical activation method. The carbon production process consisted of potassium hydroxide (KOH) impregnation followed by pyrolysis in N2 at 600-900 °C for 0-2 hr. The activation method can produce carbons with a surface area (SA) and total pore volume as high as 470 m\\/g and 0.57 cm\\/g, respectively. The influence of

Hsisheng Teng; Yu-Chuan Lin; Li-Yeh Hsu

2000-01-01

243

Cluster Ion Implantation for Process Application -Carbon Cluster co-Implantation-  

NASA Astrophysics Data System (ADS)

For beyond 32 nm NMOS device fabrication, Cluster Carbon co-implantation process is experimentally evaluated. It is found that using Cluster Carbon co-implantation, instead of Ge PAI plus single Carbon co-implantation, Phosphorus (P) TED was suppressed and the junction depth Xj are reduced by 10 nm for SDE condition and by 17 nm for SD condition when the Cluster Carbon effective dose 2×1015/cm2. The sheet resistivity Rs of 280 ?/sq for SDE condition is increased with the increment of the Carbon dose, but the Rs×Xj product 7156 ?/sq.nm has a minimum value is confirmed. The difference of the Cluster Carbon co-implantation to the monomer Carbon implantation is evaluated and the Cluster Carbon PAI effect makes higher activation of the P dopnt after annealing.

Tanjyo, M.; Nagayama, T.; Onoda, H.; Hamamoto, N.; Umisedo, S.; Koga, Y.; Une, H.; Maehara, N.; Kawamura, Y.; Hashino, Y.; Nakashima, Y.; Hashimoto, M.; Tokoro, N.; Nagai, N.; Sekar, K.; Krull, W.

2011-01-01

244

Mechanism of action of electrochemically active carbons on the processes that take place at the negative plates of lead-acid batteries  

Microsoft Academic Search

It is known that negative plates of lead-acid batteries have low charge acceptance when cycled at high rates and progressively accumulate lead sulphate on high-rate partial-state-of-charge (HRPSoC) operation in hybrid-electric vehicle (HEV) applications. Addition of some carbon or graphite forms to the negative paste mix improves the charge efficiency and slows down sulfation of the negative plates. The present investigation

D. Pavlov; T. Rogachev; P. Nikolov; G. Petkova

2009-01-01

245

HEMP-derived activated carbon fibers by chemical activation with phosphoric acid  

Microsoft Academic Search

Activated carbon fibers were prepared by chemical activation of hemp fibers with phosphoric acid at different carbonization temperatures and impregnation ratios. Surface properties of the activated carbons fibers were significantly influenced by the activation temperature and the impregnation ratio. An increase of either of these parameters produced a high development of the porous structure of the fibers. Activated carbon fibers

J. M. Rosas; J. Bedia; J. Rodríguez-Mirasol; T. Cordero

2009-01-01

246

Preparation of High Surface Area Mesoporous Activated Carbon: Kinetics and Equilibrium Isotherm  

Microsoft Academic Search

Activated carbon prepared from palm shell by phosphoric acid impregnation, at significantly favorable experimental conditions is characterized for the porous nature and adsorption of methylene blue dye molecules. The activation is carried out using a 2-stage activation process with the activation in a self generated atmosphere. An activation temperature of 500 °C, with an activation time of 75 minutes using

W. C. Lim; C. Srinivasakannan; V. Doshi

2012-01-01

247

Nitrogen activated-carbon sorption compressor  

NASA Astrophysics Data System (ADS)

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

Tzabar, Nir; Grossman, Gershon

2012-06-01

248

Phenol degradation by microorganisms adsorbed on activated carbon  

Microsoft Academic Search

The phenol degradation by Candida sp. and Pseudomonas sp. immobilized on activated carbon was investigated. Thanks to its great adsorptive surface, activated carbon is suited as supporting material for microorganisms and also provides a high adsorption capacity for phenol.

H. M. Ehrhardt; H. J. Rehm

1985-01-01

249

Ultrasound-assisted synthesis and processing of carbon materials  

NASA Astrophysics Data System (ADS)

Part I: Porous carbons are of interest in many applications because of their high surface areas and other physicochemical properties, and much effort has been directed towards developing new methods for controlling the porosity of carbons. Ultrasonic spray pyrolysis (USP) is an aerosol method suitable for large-scale, continuous synthesis of materials. Ultrasound is used to create aerosol droplets of a precursor solution which serve as micron-sized spherical reactors for materials synthesis. This work presents a precursor system for the template-free USP synthesis of porous carbons using low-cost precursors that do not evolve or require hazardous chemicals: sucrose was used as the carbon source, and sodium carbonate, sodium bicarbonate, or sodium nitrate was added as a decomposition catalyst and porogen. The USP carbons had macroporous interiors and microporous shells with surface areas as high as 800 m2/g and a narrow pore size distribution. It was determined that the interior porosity was a result of the gas evolution from salt decomposition and not from the presence of a salt template. Porous carbon is frequently used as a catalyst support because it provides high surface area and it is chemically and physically stable under many anoxic reaction conditions. Typically, the preparation of supported catalysts requires multiple steps for carbonization and metal impregnation. In this work, iron-impregnated porous carbon microspheres (Fe-C) were prepared by a one-step USP process by incorporating both the carbon and metal sources into the precursor solution. Carbonization, pore formation, metal impregnation, and metal activation occurred simultaneously to produce Fe-C materials with surface areas as high as 800 m2/g and up to 10 wt% Fe incorporated as nanoparticles < 20 nm in diameter. Fe-C was used as a catalyst to reduce aqueous hexavalent chromium, which demonstrated the accessibility of the iron nanoparticles despite the fact that they are likely encapsulated in the porous carbon support. Part II: The effects of high intensity ultrasound arise from acoustic cavitation: the formation, growth, and collapse of bubbles in a liquid. Bubble collapse produces intense localized heating (˜5000 K), high pressures (˜300 atm), and enormous heating and cooling rates (>109 K/sec). In solid-liquid slurries, surface erosion and particle fracture occur due to the shockwaves and microjets formed from asymmetric bubble collapse at extended surfaces. The chemical and physical effects of ultrasound have been studied as an adjunct to the traditional chemical pretreatment of lignocellulosic biomass for ethanol production. Lignocellulosic biomass consists of cellulose, hemicellulose, and lignin. The surface effects of ultrasound were used in this work to increase the accessibility of the cellulose, which can be converted to glucose and then fermented into ethanol. The lignocellulosic biomass used in this work was Miscanthus x giganteus (Mxg) which was grown at the University of Illinois at Urbana-Champaign. The chemical effects of NaOH pretreatment on Mxg were enhanced by ultrasound: greater delignification and a significant increase in the amount of pores >5 nm were observed. ˜ 70% of the theoretical glucose yield was obtained by enzymatic saccharification of the ultrasound-assisted NaOH-pretreated Mxg; this is comparable to the yields that can be obtained by traditional alkaline pretreatments, but it was achieved in a shorter time and at a lower temperature. Because the apparatus used for laboratory studies is not a likely device for scale-up, the economics of ultrasound with regards to energy balance are not yet resolved.

Fortunato, Maria E.

250

Dynamic adsorption of radon by activated carbon.  

PubMed

The adsorption of radon on activated carbon has been used in or considered for a number of applications, including in situ decay beds, cyclic decontamination systems, and diffusive samplers. And although there are numerous measurements of the adsorption coefficients of specific activated carbons for radon, each of these applications depends on knowing, in addition to the adsorption coefficient for radon, the mass transfer factors describing its dynamic adsorption. Here we used a standard procedure in gas chromatography and chemical engineering, the spreading of a pulse as it passes through a bed of adsorbent, to determine these mass transfer factors. For this application, this procedure is developed further to correct the radon adsorption data for distortions caused by the decay of radon and by the presence of radon decay products in the detector. The results from eight activated carbons show a wide variation in the mass transfer coefficients for radon, which could affect significantly the suitability of adsorbents, as demonstrated here by the effect that mass transfer has on the performance of in situ decay beds. PMID:15761299

Gaul, Wayne C; Underhill, Dwight W

2005-04-01

251

Comparison of textile dyeing effluent adsorption on commercial activated carbon and activated carbon prepared from olive stone by ZnCl 2 activation  

Microsoft Academic Search

Adsorption of Remazol Red B on activated carbon prepared from olive stone and commercial activated carbon from aqueous solutions was compared. Different activating agent (ZnCl2) amounts and adsorbent particle size were studied to optimize adsorbent surface area. The adsorptive property of commercial activated carbon and activated carbon prepared from olive stone were investigated in terms of adsorbent dose, temperature, equilibrium

Mehmet U?urlu; Ahmet Gürses; Metin Aç?ky?ld?z

2008-01-01

252

Supercritical fluid extraction and temperature-programmed desorption of phenol and its oxidative coupling products from activated carbon  

Microsoft Academic Search

Activated carbon remains one of the most economical adsorbents for the removal of contaminants from water. In particular, activated carbon is known to have an extremely high affinity for phenol and its derivatives. This has been shown to be the result of a catalytic process wherein activated carbon catalyzes the oxidative coupling reactions of phenol in aqueous solution when molecular

Raashina Humayun; Gurkan Karakas; Philip R. Dahlstrom; Umit S. Ozkan; David L. Tomasko

1998-01-01

253

New indicator for the evaluation of the wood carbonization process  

SciTech Connect

Evaluation of the results of a carbonization process is usually carried out by means of indicators such as mass yield, energy yield, or balanced mass yield. However, these indicators have some limits or drawbacks. A new indicator, the reference mass yield, is defined, based on the results of a well-controlled laboratory experimentation. This reference mass yield combines the mass yield and the fixed carbon content of the charcoal. It is a constant independent of the fixed carbon content, hence of the carbonization temperature. Some carbonization results from the literature are evaluated by means of the reference mass yield.

Schenkel, Y.; Temmerman, M.; Belle, J.F. van; Vankerkove, R.

1999-12-01

254

Preparation and characterization of activated carbon from demineralized tyre char  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

255

Processing of Activated Core Components  

SciTech Connect

Used activated components from the core of a NPP like control elements, water channels from a BWR, and others like in-core measurement devices need to be processed into waste forms suitable for interim storage, and for the final waste repository. Processing of the activated materials can be undertaken by underwater cutting and packaging or by cutting and high-pressure compaction in a hot cell. A hot cell is available in Germany as a joint investment between GNS and the Karlsruhe Research Center at the latter's site. Special transport equipment is available to transport the components ''as-is'' to the hot cell. Newly designed underwater processing equipment has been designed, constructed, and operated for the special application of NPP decommissioning. This equipment integrates an underwater cutting device with an 80 ton force underwater in-drum compactor.

Friske, A.; Gestermann, G.; Finkbeiner, R.

2003-02-26

256

INHIBITORY EFFECT OF SORBITOL ON ACETAMINOPHEN ADSORPTION BY ACTIVATED CARBON  

Microsoft Academic Search

The effective use of activated carbon as oral adsorbent in the primary treatment of acute acetaminophen poisoning was studied. The adsorption characteristics of acetaminophen onto activated carbons in presence of sorbitol were investigated in vitro. Both the equilibrium amount adsorbed and the removal rate of acetaminophen onto activated carbon were decreased with the increase of sorbitol concentration in solutions. The

Takeo Nakamura; Yoshihito Oida; Kazuoki Matsumoto; Naohito Kawasaki; Seiki Tanada

2002-01-01

257

REACTION OF ACTIVATED CARBON WITH AQUEOUS CHLORINE AND CHLORINE DIOXIDE  

EPA Science Inventory

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

258

REMOVAL OF DYE BY IMMOBILISED PHOTOCATALYST LOADED ACTIVATED CARBON  

Microsoft Academic Search

The ability of activated carbon to adsorb and titanium dioxide to photodegrade 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

Zulkarnain Zainal; Chang Sook Keng; Abdul Halim Abdullah

259

Prediction of equilibrium adsorption of water onto activated carbon  

Microsoft Academic Search

In applications such as VOC removal from humid air streams and steam regeneration of activated carbon, adsorption of water vapor has been encountered. The equilibrium adsorption of water onto activated carbon is a frequently encountered phenomenon in the industrial operation of adsorbers. This situation highlights a need for a method of prediction of equilibrium adsorption of water onto activated carbon

Madhusudhan Huggahalli; James R. Fair

1996-01-01

260

Less-costly activated carbon for sewage treatment  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

261

Desorption by ultrasound: Phenol on activated carbon and polymeric resin  

Microsoft Academic Search

An experimental feasibility study of using ultrasound to accomplish the difficult desorption of phenol from activated carbon and polymeric resin adsorbents is discussed. The desorption rates of activated carbon were found to significantly increase by ultrasound at 40 kHz and 1.44 MHz. Attrition of the activated carbon due to cavitation could be prevented by operating at a higher frequency and

Salil U. Rege; Ralph T. Yang; Charles A. Cain

1998-01-01

262

Adsorption of hydrogen sulphide (H 2S) by activated carbons derived from oil-palm shell  

Microsoft Academic Search

Adsorption of hydrogen sulphide (H2S) onto activated carbons derived from oil palm shell, an abundant solid waste from palm oil processing mills, by thermal or chemical activation method was investigated in this paper. Dynamic adsorption in a fixed bed configuration showed that the palm-shell activated carbons prepared by chemical activation (KOH or H2SO4 impregnation) performed better than the palm-shell activated

Jia Guo; Ye Luo; Aik Chong Lua; Ru-an Chi; Yan-lin Chen; Xiu-ting Bao; Shou-xin Xiang

2007-01-01

263

Adsorption of Organic Vapour Pollutants on Activated Carbon  

NASA Astrophysics Data System (ADS)

Emissions of organic vapor pollutants, arising mainly from anthropogenic sources have major environmental impact and the low emission levels required by increasingly stringent legislation are difficult to achieve. Adsorption on activated carbon can be used as a final stage for removal of very low concentrations of volatile organic pollutants present in air and gas streams. Isotherms and adsorption kinetics for a range of carbons with different porous structures and volatile organic compounds (VOCs) with a range of properties provide an improved understanding of the relationship between pore structure, adsorptive properties and adsorption characteristics. Competitive adsorption of other species present in gas flows, in particular water vapor, reduces adsorption capacity and kinetics. Laboratory measurements, which simulate process conditions, for example, very low vapor pressure, high temperature and competitive adsorption; provide an insight into the mechanisms associated with adsorption processes allowing process optimization.

Fletcher, A. J.; Kennedy, M. J.; Zhao, X. B.; Bell, J. B.; Thomas, K. Mark

264

COD removal from industrial wastewater using activated carbon prepared from animal horns  

Microsoft Academic Search

The present study was undertaken to compare the adsorption efficiency of activated carbon prepared from animal horns (AHC), which is both a waste and a pollutant and a commercial activated carbon (CAC) with respect to uptake of the organic components responsible for the chemical oxygen demand (COD) of industrial wastewater. The adsorption process was examined in terms of its equilibria

Emmanuel O. Aluyor; Olalekan A. M. Badmus

265

Sorption of boric acid and borax by activated carbon impregnated with various compounds  

Microsoft Academic Search

The separation of boron compounds, boric acid and borax from aqueous solution by activated carbon before and after impregnation with various compounds was studied. A series of activated carbons was prepared from coconut shell impregnated with calcium and barium chlorides, citric and tartaric acids. The examined processes were performed in batch and continuous systems under equilibrium and dynamic conditions. Impregnation

Lj. V. Rajakovi?; M. Dj. Risti?

1996-01-01

266

Role of the activated carbon surface chemistry in the adsorption of phenanthrene  

Microsoft Academic Search

The influence of the surface chemistry in the adsorption of Phenanthrene (Phe) vapor on oxidized activated carbons has been studied. All the runs were performed in a fixed bed reactor with a process temperature of 150 °C, similar to the observed in the flue gases from energy generation systems. A commercial activated carbon was chosen as raw material. The oxidized

T Garc??a; R Murillo; D Cazorla-Amorós; A. M Mastral; A Linares-Solano

2004-01-01

267

Heterogeneous and homogeneous catalytic ozonation of benzothiazole promoted by activated carbon: Kinetic approach  

Microsoft Academic Search

Ozone oxidation combined with activated carbon adsorption (O3\\/AC) has recently started to be developed as a single process for water and wastewater treatment. While a number of aspects of aqueous ozone decomposition are well understood, the importance and relationship between aqueous ozone decomposition and organic contaminant degradation in the presence of activated carbon is still not clear. This study focuses

Héctor Valdés; Claudio A. Zaror

2006-01-01

268

Destruction of methyl ethyl ketone vapor by ozone on activated carbon  

Microsoft Academic Search

This study attempts to combine the technologies of adsorption of volatile organic compounds (VOCs) on activated carbon and the oxidation of the VOCs by ozone (O3). In the adsorption\\/oxidation process, the effects of ozone on the adsorption characteristics of methyl ethyl ketone (MEK) vapor on activated carbon are investigated. The kinetic parameters of the reaction for MEK vapor and O3

Hung-Ming Wu; Jiann-Hwa You

2007-01-01

269

Adsorptive removal of phthalate ester (Diethyl phthalate) from aqueous phase by activated carbon: A kinetic study  

Microsoft Academic Search

Adsorptive studies were carried out on Di-ethyl phthalate (DEP) removal from aqueous phase onto activated carbon. Batch sorption studies were performed and the results revealed that activated carbon demonstrated ability to adsorb DEP. Influence of varying experimental conditions such as DEP concentration, pH of aqueous solution, and dosage of adsorbent were investigated on the adsorption process. Sorption interaction of DEP

S. Venkata Mohan; S. Shailaja; M. Rama Krishna; P. N. Sarma

2007-01-01

270

Immobilization of phenol in cement-based solidified\\/stabilized hazardous wastes using regenerated activated carbon: role of carbon  

Microsoft Academic Search

The use of regenerated activated carbon as an immobilizing additive for phenol in solidification\\/stabilization (S\\/S) processes was investigated. The adsorption capacity of regenerated carbon was compared to that of the virgin form and was found to be very close. The effects of pH and Ca(OH)2 concentration within the S\\/S monolith on the adsorption process were also examined. Kinetic tests were

Hassan A Arafat; Vikram M Hebatpuria; Hong Sang Rho; Neville G Pinto; Paul L Bishop; Relva C Buchanan

1999-01-01

271

Carbon Monoxide Dehydrogenase Activity in Bradyrhizobium japonicum  

PubMed Central

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

Lorite, Maria J.; Tachil, Jorg; Sanjuan, Juan; Meyer, Ortwin; Bedmar, Eulogio J.

2000-01-01

272

Amorphous carbon contamination monitoring and process optimization for single-walled carbon nanotube integration  

Microsoft Academic Search

We detail the monitoring of amorphous carbon deposition during thermal chemical vapour deposition of carbon nanotubes and propose a contamination-less process to integrate high-quality single-walled carbon nanotubes into micro-electromechanical systems. The amorphous content is evaluated by confocal micro-Raman spectroscopy and by scanning\\/transmission electron microscopy. We show how properly chosen process parameters can lead to successful integration of single-walled nanotubes, enabling

A. Jungen; C. Stampfer; L. Durrer; T. Helbling; C. Hierold

2007-01-01

273

Catalytic ozonation of dimethyl phthalate over cerium supported on activated carbon  

Microsoft Academic Search

Cerium supported on activated carbon (Ce\\/AC), which was prepared by dipping method, was employed to degrade dimethyl phthalate (DMP) in water. The mineral matter present in the activated carbon positively contributes to its activity to enhance DMP ozonation process. A higher dipping Ce(NO3)3 concentration and calcination process increase its microporous volume and surface area, and decreases its exterior surface area.

Laisheng Li; Weiying Ye; Qiuyun Zhang; Fengqiang Sun; Ping Lu; Xukai Li

2009-01-01

274

Facilitation of High-Rate NADH Electrocatalysis Using Electrochemically Activated Carbon Materials.  

PubMed

Electrochemical activation of glassy carbon, carbon paper and functionalized carbon nanotubes via high-applied-potential cyclic voltammetry leads to the formation of adsorbed, redox active functional groups and increased active surface area. Electrochemically activated carbon electrodes display enhanced activity toward nicotinamide adenine dinucleotide (NADH) oxidation, and more importantly, dramatically improved adsorption of bioelectrochemically active azine dyes. Adsorption of methylene green on an electroactivated carbon electrode yields a catalyst layer that is 1.8-fold more active toward NADH oxidation than an electrode prepared using electropolymerized methylene green. Stability studies using cyclic voltammetry indicate 70% activity retention after 4000 cycles. This work further facilitates the electrocatalysis of NADH oxidation for bioconversion, biosensor and bioenergy processes. PMID:24780505

Li, Hanzi; Li, Rui; Worden, Robert M; Barton, Scott Calabrese

2014-05-14

275

Void forming pyrolytic carbon coating process  

SciTech Connect

A pyrolytic carbon coated nuclear fuel particle and method of making it are disclosed. The fuel particle has a core composed of a refractory compound of an actinide metal. The pyrolytic carbon coating surrounds the core so as to provide a void volume therebetween. The coating has an initial density of no greater than 1.45 grams/cm{sup 3} and an anisotropy factor than 3.0 and a final density upon heat treatment above about 2,000 C of greater than 1.7 grams/cm{sup 3} and an anisotropy factor greater than 5.

Beatty, R.L.; Cook, J.L.

2000-06-27

276

Void forming pyrolytic carbon coating process  

DOEpatents

A pyrolytic carbon coated nuclear fuel particle and method of making it. The fuel particle has a core composed of a refractory compound of an actinide metal. The pyrolytic carbon coating surrounds the core so as to provide a void volume therebetween. The coating has an initial density of no greater than 1.45 grams/cm.sup.3 and an anisotropy factor than 3.0 and a final density upon heat treatment above about 2000.degree. C. of greater than 1.7 grams/cm.sup.3 and an anisotropy factor greater than 5.

Beatty, Ronald L. (Oak Ridge, TN); Cook, Jackie L. (Oak Ridge, TN)

2000-01-01

277

Granular and monolithic activated carbons from KOH-activation of olive stones  

Microsoft Academic Search

Different activated carbons were prepared by KOH-activation of carbonized olive stones by varying the KOH\\/carbon weight ratio and the particle size of the precursor. The activated carbon with the best surface characteristics was furthermore steam-activated. Other activated carbon was obtained by using directly olive stones as raw material. In this case the precursor particles were broken by the KOH solution,

Ruth Ubago-Pérez; Francisco Carrasco-Marín; David Fairén-Jiménez; Carlos Moreno-Castilla

2006-01-01

278

Characteristics and humidity control capacity of activated carbon from bamboo  

Microsoft Academic Search

Activated carbons were prepared from bamboo by chemical activation with K2CO3 or physical activation with CO2. The structural and surface chemical characteristics of the activated carbons were determined by N2 adsorption–desorption and Boehm titration, respectively. The water vapor adsorption properties of the activated carbons with various pore structures (preparation conditions) were examined. The relationship between water vapor adsorption capacity and

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

2010-01-01

279

Acid sorption regeneration process using carbon dioxide  

DOEpatents

Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent in the presence of carbon dioxide under pressure. The acids are freed from the sorbent phase by a suitable regeneration method, one of which is treating them with an organic alkylamine solution thus forming an alkylamine-carboxylic acid complex which thermally decomposes to the desired carboxylic acid and the alkylamine.

King, C. Judson (Kensington, CA); Husson, Scott M. (Anderson, SC)

2001-01-01

280

Comparison of physicochemical properties of nitrogen-enriched activated carbons prepared by physical and chemical activation of brown coal  

SciTech Connect

Nitrogen-enriched active carbon has been obtained from Polish brown coal from the 'Konin' colliery. The process of ammoxidation by a mixture of ammonia and air at the ratio of 1:3 has been performed at two temperatures (300 and 350{degree}C) at different stages of the production, that is, at that of precursor, char, and active carbon. It has been shown that the stage at which the process of ammoxidation is conducted has profound effect on the amount of nitrogen introduced into the carbon structure. The carbonization and activation (by steam or KOH) of nitrogen-enriched samples leads to significant reduction of the nitrogen content. The final products were microporous active carbons of well-developed surface area varying from 604 to 3181 m{sup 2}/g and having nitrogen content from 0.4 to 6.5 wt%, showing different acid-base character of the surface. 28 refs., 7 tabs.

Piotr Nowicki; Robert Pietrzak; Helena Wachowska [Adam Mickiewicz University, Poznan (Poland). Laboratory of Coal Chemistry and Technology

2008-11-15

281

Material Processing with Hydrogen and Carbon Monoxide on MARS.  

National Technical Information Service (NTIS)

Several novel proposals are examined for propellant production from carbon dioxide and monoxide and hydrogen. Potential uses were also examined of CO as a fuel or as a reducing agent in metal oxide processing as obtained or further reduced to carbon. Hydr...

A. F. Hepp G. A. Landis D. L. Linne

1991-01-01

282

Processing and applications of carbon based nano-materials  

Microsoft Academic Search

Carbon-based nanomaterials, including single walled carbon nanotubes (SWNTs) and graphite nanoplatelets (GNPs, multi-layer graphene), possess exceptional electrical, thermal and mechanical properties coupled with high aspect ratio and high temperature stability. These unique properties have attracted increased attention during the past decade. These materials form the basis of the work presented here, which includes research targeting fabrication, processing and applications in

Aiping Yu

2008-01-01

283

Material processing with hydrogen and carbon monoxide on Mars  

Microsoft Academic Search

Several novel proposals are examined for propellant production from carbon dioxide and monoxide and hydrogen. Potential uses were also examined of CO as a fuel or as a reducing agent in metal oxide processing as obtained or further reduced to carbon. Hydrogen can be reacted with CO to produce a wide variety of hydrocarbons, alcohols, and other organic compounds. Methanol,

Aloysius F. Hepp; Geoffrey A. Landis; Diane L. Linne

1991-01-01

284

Adsorbed natural gas storage with activated carbon  

SciTech Connect

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

Sun, Jian; Brady, T.A.; Rood, M.J. [Univ. of Illinois, Urbana, IL (United States)] [and others

1996-12-31

285

BACTERIA ASSOCIATED WITH GRANULAR ACTIVATED CARBON PARTICLES IN DRINKING WATER  

EPA Science Inventory

A sampling protocol was developed to examine particles released from granular activated carbon filter beds. A gauze filter/Swinnex procedure was used to collect carbon fines from 201 granular activated carbon-treated drinking water samples over 12 months. Application of a homogen...

286

Applicability of Activated Carbon to Treatment of Waste Containing Iodine-Labeled Compounds  

Microsoft Academic Search

A timber industry waste was transformed to activated carbon by a one-step chemical activation process using H3PO4 (H). The used activated carbon (SDH) was characterized by N2 adsorption, FTIR, density, pH, point of zero charge pHpzc, moisture and ash content. Methylene blue (MB) and the iodine number were calculated by adsorption from the solution. The applicability of the different activated

H. M. H. Gad; N. R. A. El-Mouhty; H. F. Aly

2009-01-01

287

Interactions of xanthines with activated carbon. II. The adsorption equilibrium  

NASA Astrophysics Data System (ADS)

In the present work, we have studied the adsorption of xanthine derivatives by activated carbon sorbents in aqueous solutions. The study comprised both kinetic, equilibrium and thermodynamic aspects. The kinetic results were reported in a previous paper; the equilibrium-related results are discussed here. The two types of carbon used exhibit some differences but the equilibrium isotherms obtained are all of the H-3 type in the classification of Giles. This suggests a high affinity of the sorbents for the sorbates. We also found that the overall adsorption process comprises more than one individual adsorption-desorption process of which one leads to the formation of a "monolayer" and the other to the "precipitation" of the sorbate on the sorbent surface (multilayer adsorption); the amount of sorbate adsorbed in monolayer form was seemingly greater in C-A14.

Navarrete Casas, R.; García Rodríguez, A.; Rey Bueno, F.; Espínola Lara, A.; Valenzuela Calahorro, C.; Navarrete Guijosa, A.

2006-06-01

288

Role of active sites in the steam activation of high unburned carbon fly ashes  

Microsoft Academic Search

Previous studies on carbon gasification have not included high unburned carbon content fly ashes, and therefore it remains unclear why not all fly ash carbon samples are equally suitable for activation. The concentration of active sites is well known to influence carbon gasification reactions. Therefore, the objective of this work was to investigate the effect of the concentration of active

Zhe Lu; M. Mercedes Maroto-Valer; Harold H. Schobert

2008-01-01

289

Electrochemical regeneration of activated carbon cloth exhausted with bentazone.  

PubMed

The electrochemical regeneration of an activated carbon cloth exhausted with a common herbicide (bentazone) was investigated under different operating conditions. The reversibility of the desorption process was confirmed by monitoring the UV spectra of the solution while cathodic polarization is being applied. Neither nanotextural nor chemical changes are produced in the carbon cloth upon polarization in the absence of the adsorbate. Upon cathodic polarization of a carbon cloth working electrode preloaded with bentazone, negative charges appear on the surface. A partial bentazone desorption results from repulsive electrostatic interactions between the negative charges on the carbon cloth and bentazone. When the electrode potential is below the thermodynamic value for cathodic decomposition of water, hydroxyl ions are liberated. Such ions provoke local pH changes that are responsible of the dissociation of bentazone and carbon surface groups to their anionic form. As a consequence of the pH increase, an almost reversible desorption of bentazone is observed. The effects of several operating parameters on the regeneration efficiency were evaluated. Higher regeneration efficiencies were attained under potentiostatic as compared to galvanostatic conditions, as OH- production strongly depends on the applied potential. PMID:18605577

Ania, Conchi O; Béguin, François

2008-06-15

290

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

SciTech Connect

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

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

2001-01-01

291

ADSORPTION AND DESORPTION OF M-XYLENE FROM SUPERCRITICAL CARBON DIOXIDE ON ACTIVATED CARBON  

Microsoft Academic Search

The equilibrium loadings of m-xylene from supercritical carbon dioxide on activated carbon are reported. The experimental data were obtained by measuring the outlet concentration of m-xylene eluted from a column packed with activated carbon until the effluent reached the input concentration. The Freundlich isotherm expression was found to correlate the experimental data satisfactorily. In a second step, the regeneration by

Jamal Benkhedda; Jean-Noël Jaubert; Danielle Barth; Carsten Zetzl; Gerd Brunner

2001-01-01

292

Unburnt carbon from coal fly ashes as a precursor of activated carbon for nitric oxide removal  

Microsoft Academic Search

The aim of this work is to evaluate the characteristics of an activated carbon obtained from unburnt carbon in coal fly ashes to be used in the removal of NO. Carbon-rich fraction was obtained by mechanical sieving of fly ashes. The mineral matter was removed by conventional HCl and HF demineralization procedure. Activation was carried out with steam at 900°C

Begoña Rubio; M. Teresa Izquierdo; M. Carmen Mayoral; M. Teresa Bona; Jose M. Andres

2007-01-01

293

DISINFECTION OF BACTERIA ATTACHED TO GRANULAR ACTIVATED CARBON  

EPA Science Inventory

Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon (GAC) particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected wit...

294

Optimization of the Regeneration Procedure for Granular Activated Carbon.  

National Technical Information Service (NTIS)

Laboratory scale experiments were conducted on the regeneration of activated carbons spent in tertiary treatment of wastewater. Wet spent carbon being regenerated thermally undergoes three regeneration stages: drying at about 220F; Pyrolysis of the adsorb...

A. J. Juhola

1970-01-01

295

Disinfection of Bacteria Attached to Granular Activated Carbon.  

National Technical Information Service (NTIS)

Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon (GAC) particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles...

M. W. LeChevallier T. S. Hassenauer A. K. Camper G. A. McFeters

1984-01-01

296

REPEATED REDUCTIVE AND OXIDATIVE TREATMENTS ON GRANULAR ACTIVATED CARBON  

EPA Science Inventory

Fenton oxidation and Fenton oxidation preceded by reduction solutions were applied to granular activated carbon (GAC) to chemically regenerate the adsorbent. No adsorbate was present on the GAC so physicochemical effects from chemically aggressive regeneration of the carbon coul...

297

Production of special activated carbon from lignite for environmental purposes  

Microsoft Academic Search

A treatment technique involving three sequential stages (demineralisation, activation and sulphur dispersion) was developed for the production of suitable activated carbons from Greek lignite. Demineralisation included three steps of acid treatment and samples received were characterised by X-ray diffraction (XRD). A two-stage activation procedure (pyrolysis under nitrogen, followed by activation under carbon dioxide atmosphere) was used for the production of

G Skodras; Th Orfanoudaki; E Kakaras; G. P Sakellaropoulos

2002-01-01

298

Activated carbon prepared from oil palm stone by one-step CO 2 activation for gaseous pollutant removal  

Microsoft Academic Search

The feasibility of preparing activated carbons from oil palm stones by one-step CO2 activation was studied. These oil palm stones are major solid wastes generated from palm-oil processing mills. Experimental results showed that the particle size of the starting material and heating rate appeared to have no significant effects on the BET surface areas of the activated carbons but CO2

Aik Chong Lua; Jia Guo

2000-01-01

299

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

National Technical Information Service (NTIS)

The method of supercritical carbon dioxide (SCF CO2) regeneration of granular activated carbon (GAC) loaded with DIMP (diisopropyl methylphosphonate) from Rocky Mountain Arsenal Well (NO. 23-120) water was investigated. A laboratory-based adsorption/regen...

R. M. O'Brien R. P. de Filippi C. E. Smith D. G. Hager

1982-01-01

300

Water Adsorption with Hysteresis Effect onto Microporous Activated Carbon Fabrics - PREPRINT.  

National Technical Information Service (NTIS)

Understanding the adsorption of water vapor onto activated carbons is important for designing processes to remove dilute contaminants from humid gas streams, such as providing protection against chemical warfare agents (CWAs), or against toxic industrial ...

B. R. Stone M. J. Rood P. D. Sullivan Z. Hashiso

2007-01-01

301

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

EPA Science Inventory

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

302

Role of activated carbon pellets in carbon dioxide removal  

Microsoft Academic Search

The removal of carbon dioxide from gas\\/air streams is more often becoming necessary in many industries for different purposes. In cryogenic air separation plant, air has to be free from carbon dioxide before its liquefaction otherwise blockage due to freezing of heat exchange equipment would result. Enrichment of methane in biogas to have fuel of higher calorific value can be

S. C Sarkar; A Bose

1997-01-01

303

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

PubMed

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

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

2000-11-01

304

Superhydrophobic activated carbon-coated sponges for separation and absorption.  

PubMed

Highly porous activated carbon with a large surface area and pore volume was synthesized by KOH activation using commercially available activated carbon as a precursor. By modification with polydimethylsiloxane (PDMS), highly porous activated carbon showed superhydrophobicity with a water contact angle of 163.6°. The changes in wettability of PDMS- treated highly porous activated carbon were attributed to the deposition of a low-surface-energy silicon coating onto activated carbon (confirmed by X-ray photoelectron spectroscopy), which had microporous characteristics (confirmed by XRD, SEM, and TEM analyses). Using an easy dip-coating method, superhydrophobic activated carbon-coated sponges were also fabricated; those exhibited excellent absorption selectivity for the removal of a wide range of organics and oils from water, and also recyclability, thus showing great potential as efficient absorbents for the large-scale removal of organic contaminants or oil spills from water. PMID:23650204

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

2013-06-01

305

Production of activated carbon from Luscar char: Experimental and modeling studies  

Microsoft Academic Search

Central composite design (CCD) was applied to study the influence of activation temperature, mass ratio of steam to char and activation time on the steam activation process of Luscar char. Two quadratic models were developed for BET surface area and yield of activated carbon using Design-Expert software. The models were used to calculate the optimum operating conditions for production of

R. Azargohar; A. K. Dalai

2005-01-01

306

The Carbon Cycle and its Role in Climate Change: Activity 1  

NSDL National Science Digital Library

In this activity (on page 1), learners role play as atoms to explore how atoms can be rearranged to make different materials. Learners group together and link arms or hold hands to form chemical bonds and act out the processes of photosynthesis and respiration. Use this activity to introduce the carbon cycle and follow this activity with two associated activities from the same resource.

Management, Us B.; Agency, Us E.; Service, Us F.; Service, Us F.; Administration, National A.; Administration, National A.

2009-01-01

307

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

308

Sodium to sodium carbonate conversion process  

DOEpatents

A method of converting radioactive alkali metal into a low level disposable solid waste material. The radioactive alkali metal is atomized and introduced into an aqueous caustic solution having caustic present in the range of from about 20 wt % to about 70 wt % to convert the radioactive alkali metal to a radioactive alkali metal hydroxide. The aqueous caustic containing radioactive alkali metal hydroxide and CO.sub.2 are introduced into a thin film evaporator with the CO.sub.2 present in an amount greater than required to convert the alkali metal hydroxide to a radioactive alkali metal carbonate, and thereafter the radioactive alkali metal carbonate is separated from the thin film evaporator as a dry powder. Hydroxide solutions containing toxic metal hydroxide including one or more metal ions of Sb, As, Ba, Be, Cd, Cr, Pb, Hg, Ni, Se, Ag and T1 can be converted into a low level non-hazardous waste using the thin film evaporator of the invention.

Herrmann, Steven D. (Idaho Falls, ID)

1997-01-01

309

Micro-scale investigation of carbonation process in partially serpentinized peridotites  

NASA Astrophysics Data System (ADS)

The carbonation of ultramafic rocks is, theoretically, the most efficient reaction to trap CO2 irreversibly in the form of solid carbonates, as predicted by equilibrium thermodynamic calculations. However, the success of industrial or natural carbonation in large ultramafic aquifers or oceanic ultramafic exposures does not only rely on the thermodynamic conditions of chemical reactions, but also on their feedback effects on the reactive surface area and on the local porosity and permeability. In addition, side processes like serpentinization, redox reactions, abiotic catalytic effects, and biological activity, can be expected in such complex natural system. Their occurrence and implications on carbon speciation and carbon transfers during hydrothermal alteration of oceanic peridotites have not been explored yet and requires detailed study of natural and/or experimental carbonation zones. We have combined petrographic and electron microscopy with SIMS, Raman and FTIR microspectroscopy on partially serpentinized peridotites drilled during the IODP leg 304 (30°N, MAR) in order to characterize the mechanisms of peridotite carbonation at the fluid-mineral interface and identify the associated speciation of carbon (inorganic and organic carbon occurrences). We present first results on zones located close to talc-tremolite sheared veins in holes 1309B and D. Associations of carbonates, porous phyllosilicates and oxides are observed in close vicinity of relict olivines that underwent a previous stage of serpentinization. The olivine-carbonate interface is nanoporous which facilitates mass transfer between fluid and mineral. The phyllosilicate identified as saponite results from the metasomatic replacement, during the carbonation stage, of previously formed serpentine. These observations do not favour reaction-induced cracking but rather a transfer-controlled process in an open system. Among the submicrometric dark clusters widely-distributed in saponite and in serpentine, vibrational microspectroscopy reveals the presence of various types of organic compounds that tend to be located close to micrometric sulphides grains. Those results underline the microscale variability of carbon speciation within hydrothermally altered peridotites. The association of reduced carbon phases with the carbonation texture suggests that CO2 conversion may not be limited to solid carbonate formation in natural systems and that biological activity and/or abiotic CO2 reduction, possibly catalyzed by Ni-rich sulphides, can occur contemporaneously. This complex association of reactions has to be unravelled further to determine the respective contribution of abiotic versus biological processes and integrate them in carbon transfers modelling through the oceanic lithosphere.

Andreani, M.; Menez, B.; Delacour, A.; Pasini, V.; Auzende, A. L.; Brunelli, D.

2012-04-01

310

Nitrogen doping of activated carbon loading Fe 2 O 3 and activity in carbon-nitric oxide reaction  

Microsoft Academic Search

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\\u000a of oxygen. Results show that Fe2O3 enhances the amount of surface oxygen complexes and facilitates nitrogen incorporation in the carbon, especially in the form\\u000a of pyridinic nitrogen. The modified carbon shows excellent

Xian-kai Wan; Xue-quan Zou; Hui-xiang Shi; Da-hui Wang

2007-01-01

311

Restricted dynamics of molecular hydrogen confined in activated carbon nanopores  

SciTech Connect

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

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

2012-01-01

312

Activated Carbon Composites for Air Separation  

SciTech Connect

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.

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

2011-09-01

313

Fabrication and processing of high-strength densely packed carbon nanotube yarns without solution processes.  

PubMed

Defects of carbon nanotubes, weak tube-tube interactions, and weak carbon nanotube joints are bottlenecks for obtaining high-strength carbon nanotube yarns. Some solution processes are usually required to overcome these drawbacks. Here we fabricate ultra-long and densely packed pure carbon nanotube yarns by a two-rotator twisting setup with the aid of some tensioning rods. The densely packed structure enhances the tube-tube interactions, thus making high tensile strengths of carbon nanotube yarns up to 1.6 GPa. We further use a sweeping laser to thermally treat as-produced yarns for recovering defects of carbon nanotubes and possibly welding carbon nanotube joints, which improves their Young's modulus by up to ?70%. The spinning and laser sweeping processes are solution-free and capable of being assembled together to produce high-strength yarns continuously as desired. PMID:22538869

Liu, Kai; Zhu, Feng; Liu, Liang; Sun, Yinghui; Fan, Shoushan; Jiang, Kaili

2012-06-01

314

Removal of bromide and iodide anions from drinking water by silver-activated carbon aerogels  

Microsoft Academic Search

The aim of this study is to analyze the use of Ag-doped activated carbon aerogels for bromide and iodide removal from drinking water and to study how the activation of Ag-doped aerogels affects their behavior. It has been observed that the carbonization treatment and activation process of Ag-doped aerogels increased the surface area value (SN2), whereas the volume of meso-(V2)

M. Sánchez-Polo; J. Rivera-Utrilla; E. Salhi; U. von Gunten

2006-01-01

315

Optimisation and significance of ATP analysis for measuring active biomass in granular activated carbon filters used in water treatment  

Microsoft Academic Search

A method for determining the concentration of active microbial biomass in granular activated carbon (GAC) filters used in water treatment was developed to facilitate studies on the interactions between adsorption processes and biological activity in such filters. High-energy sonication at a power input of 40W was applied to GAC samples for the detachment of biomass which was measured as adenosine

Aleksandra Magic-Knezev; Dick van der Kooij

2004-01-01

316

Comparison of Cadmium Ion Adsorption on Various ACTIVATED CARBONS  

Microsoft Academic Search

Studies on the removal of cadmium(II) ions from aqueous solutions by adsorption on various activated carbons [commercial activated carbon (CAC) and chemically prepared activated carbons (CPACs) from raw materials such as straw, saw dust and datesnut] have been carried out with an aim to obtain information on treating effluents containing Cd(II) ions. Factors influencing the adsorption of Cd(II) ions from

Nagarethinam Kannan; Gurusamy Rengasamy

2005-01-01

317

Adsorption of chromium by activated carbon from aqueous solution  

Microsoft Academic Search

Adsorption isotherms of Cr(III) and Cr(VI) ions on two samples of activated carbon fibres and two samples of granulated activated carbons from aqueous solutions in the concentration range 20–1000 mg\\/l have been studied. The adsorption isotherms have been determined after modifying the activated carbon surfaces by oxidation with nitric acid, ammonium persulphate, hydrogen peroxide and oxygen gas at 350°C and

Diksha Aggarwal; Meenakshi Goyal; R. C. Bansal

1999-01-01

318

Nickel adsorption by sodium polyacrylate-grafted activated carbon  

Microsoft Academic Search

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 55.7mgg?1. X-ray absorption spectroscopy showed that the adsorbed nickel on activated carbon and irradiation-grafted activated carbon was coordinated with 6

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

2009-01-01

319

Operation of Membrane Bioreactor with Powdered Activated Carbon Addition  

Microsoft Academic Search

The effect of powdered activated carbon (PAC) addition to the activated sludge (AS) in a membrane bioreactor (MBR) has been investigated. The long term nature of the tests allowed the PAC to gradually incorporate into the biofloc forming biologically activated carbon (BAC). One series of tests involved 4 bench scale (2 L) MBRs operated at sludge retention times (SRTs) of 30

Choon Aun Ng; Darren Sun; Anthony G. Fane

2006-01-01

320

Preparation of activated carbons from agricultural residues for pesticide adsorption  

Microsoft Academic Search

Activated carbons (ACs) can be used not only for liquid but also for vapour phase applications, such as water treatment, deodorisation, gas purification and air treatment. In the present study, activated carbons produced from agricultural residues (olive kernel, corn cobs, rapeseed stalks and soya stalks) via physical steam activation were tested for the removal of Bromopropylate (BP) from water. For

Ourania A. Ioannidou; Anastasia A. Zabaniotou; George G. Stavropoulos; Triantafyllos A. Albanis

2010-01-01

321

CYANIDE REMOVAL FROM REFINERY WASTEWATER USING POWDERED ACTIVATED CARBON  

EPA Science Inventory

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

322

N-containing activated carbons for CO2 capture  

Microsoft Academic Search

A series of SK-activated carbons were prepared by carbonising soya beans in the presence of KOH as activation agent. Different activation temperatures were applied to study the influence of preparation conditions on the surface properties of the carbons and their CO2 adsorption capacity. It was found that the CO2 adsorption capacity is directly related to the nature of surface basic

Chao Liu; Wei Xing; Jin Zhou; Shu-ping Zhuo

2012-01-01

323

Process for producing carbon monoxide and hydrogen from methanol  

SciTech Connect

A process is described for producing carbon monoxide and hydrogen which comprises contacting methanol vapor at a temperature of 200 degrees to 300 degrees C with an indirectly heated zinc containing catalyst to obtain an effluent gas in which the components of carbon monoxide and hydrogen constitute at least 90% by volume of said gas. At least a part of the impurities from said effluent gas are removed and said effluent gas is deparated into its carbon monoxide and hydrogen components by adsorption. The effluent gas can be separated into its carbon monoxide and hydrogen components by use of a plurality of adsorbers containing zeolite-type molecular sieve material where the zeolite is substantially permeable to hydrogen but sorbs carbon monoxide.

Jockel, H.; Marschner, F.; Moller, F.W.; Mortel, H.

1982-02-23

324

The reversibility of adsorption of gold cyanide on activated carbon  

NASA Astrophysics Data System (ADS)

Much controversy exists about the mechanism by which gold cyanide adsorbs on activated carbon. It is not the purpose of this article to explain the exact adsorption mechanism but, rather, to investigate the factors affecting the reversibility of adsorbed gold cyanide. Whereas Au(CN){2/-} is soluble in water, AuCN and Au require the addition of cyanide to form Au(CN){2/-}. The reversibility of the adsorption of gold onto carbon is a function of the nature of the adsorbed gold and determines the need for cyanide in the elution process, which affects the operating costs of a carbon-in-pulp (CIP) plant. The fraction of adsorbed Au(CN){2/-} that will be decomposed to AuCN was found to be a function of the pH and temperature of the solution and the type of activated carbon used. It was observed that two different batches of carbon from the same manufacturer yielded widely different ratios of AuCN to Au(CN){2/-}, although their specifications did not differ much. These results were confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). A combination of low pH and high temperature, as is found in the hot acid wash step of an AARL elution, leads to the reduction of both Au(1) species to metallic gold, Au(0). The fraction of the adsorbed Au(CN){2/-} that is converted to AuCN or Au(0) no longer participates in the equilibrium between Au(CN){2/-} in solution and Au(CN){2/-} in the adsorbed phase. It was observed that the isotherm for desorption is higher than the isotherm for adsorption by a percentage which is, on average, equal to the percentage of Au(CN){2/-} converted to AuCN or Au(0).

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

1993-06-01

325

Influence of carbon–oxygen surface complexes on the surface acidity of tungsten oxide catalysts supported on activated carbons  

Microsoft Academic Search

Tungsten oxide catalysts supported on activated carbons were prepared by using tungsten hexacarbonyl, ammonium tungstate, and tungsten pentaethoxide as precursors. An activated carbon was obtained from olive stone by physical activation. A portion of this activated carbon was oxidized with ammonium peroxydisulfate in order to introduce different oxygen surface complexes. Subsequently, different portions of this oxidized activated carbon were heat

Carlos Moreno-Castilla; Agust??n F. Pérez-Cadenas; Francisco J. Maldonado-Hódar; Francisco Carrasco-Mar??n; José Luis G. Fierro

2003-01-01

326

Production of charcoal and activated carbon at elevated pressure  

Microsoft Academic Search

With its wide range of properties, charcoal finds many commercial applications for domestic cooking, refining of metals (steel, copper, bronze, nickel, aluminum and electro-manganese), production of chemicals (carbon disulfide, calcium carbide, silicon carbide, sodium cyanide, carbon black, fireworks, gaseous chemicals, absorbents, soil conditioners and pharmaceuticals), as well as production of activated carbon and synthesis gas. In 1991, the world production

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

1995-01-01

327

Adsorption of natural gas and biogas components on activated carbon  

Microsoft Academic Search

Experimental results are presented for the adsorption equilibria of methane, ethane, propane, butane, carbon dioxide, and nitrogen, as well as natural gas odorants tert-butyl mercaptan and tetrahydrothiophene, on an activated carbon with the desirable characteristics for use in a guard bed for adsorbed natural gas storage, but that can also be applied for separation of biogas components, such as carbon

Isabel A. A. C. Esteves; Marta S. S. Lopes; Pedro M. C. Nunes; José P. B. Mota

2008-01-01

328

Preparation of carbon blacks by liquid phase plasma (LPP) process.  

PubMed

In this study, carbon black nanoparticles were synthesized by Liquid Phase Plasma (LPP) technique; plasma generated in the organic solvent of benzene at 4.9 kV with the pulse frequency of 15 kHz and width of 5 micros transformed the carbon atoms in the solvent into carbon blacks by oxidation and reduction reactions. Graphite phase was found to be introduced into the carbon blacks without any additional processes due to the characteristics of LPP process, resulting in a higher G/D ratio of 0.92, compared to 0.83 of commercial Ketjen carbon blacks. For the performance improvement, heat treatment was employed and its parameters such as temperature and duration time were optimized in relation to the crystallinity and specific surface area of the carbon blacks. Carbon blacks heat treated at 450 degrees C in the air for 20 min were measured to have the discharge capacity of 1750 mAh/g and irreversible charging and discharging capacity ratio of 52.6%. PMID:24245259

Yun, Kang-Seop; Kim, Bo-Ra; Kang, Woo-Seung; Jung, Sang-Chul; Myung, Seung-Taek; Kim, Sun-Jae

2013-11-01

329

Record Methane Storage in Monolithic and Powdered Activated Carbons  

NASA Astrophysics Data System (ADS)

The Alliance for Collaborative Research in Alternative Fuel Technology (ALL-CRAFT) has developed activated carbons from corn cob as adsorbent materials for methane gas storage by physisorption at low pressures. KOH activated carbons were compressed into carbon monolith using chemical binders. High pressure methane isotherms up to 250 bar at room temperature on monolithic and powdered activated carbons were measured gravimetrically and volumetrically. Record methane storage capacities of 250 g CH4/kg carbon and 130 g CH4/liter carbon at 35 bar and 293 K have been achieved. BET surface area, porosity, and pore size distributions were measured from sub-critical nitrogen isotherms. Pore entrances were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A prototype adsorbed natural gas (ANG) tank, loaded with carbon monoliths, was tested in Kansas City.

Soo, Yuchoong; Nordwald, E.; Hester, B.; Romanos, J.; Isaacson, B.; Stalla, D.; Moore, D.; Kraus, M.; Burress, J.; Dohnke, E.; Pfeifer, P.

2010-03-01

330

Hydrometallurgical processing of carbon steel EAF dust  

Microsoft Academic Search

In this study, the hydrometallurgical processing of electric arc furnace (EAF) steelmaking dust is investigated on a laboratory scale under normal temperature and pressure conditions. The behaviour of zinc and iron under the influence of sulphuric acid as the leaching agent is discussed. The dependence between the temperature and acid concentration is investigated. The main aim is the transfer of

Tomáš Havlík; Bruna Vidor e Souza; Andrea Moura Bernardes; Ivo André Homrich Schneider; Andrea Miškufová

2006-01-01

331

Carbon black from coal by the HYDROCARB process  

SciTech Connect

The HYDROCARB process was conceived and developed for the purpose of producing a clean carbon fuel and coproduct gaseous and liquid fuel coproducts from any carbonaceous feedstock and particularly from coal. The process basically consists of two major steps. In the first step, coal is hydrogenated to produce methane. In this step, the carbonaceous raw material is gasified with a recycled hydrogen-rich gas stream to form a light hydrocarbon, methane-rich gas, while the non-volatile ash remains behind. With the optional addition of limestone to the feed material, sulfur in the feedstock is removed as non-volatile calcium sulfide which is later oxidized to calcium sulfate for disposal. The methane-rich gas which also contains carbon monoxide and smaller amounts of water and carbon dioxide is sent to a recuperative condenser. For the production of methanol, the carbon monoxide and hydrogen in the process gas is catalytically combined to produce methanol. The deoxygenated methane-rich gas stream is then sent to a methane decomposer where the methane is cracked to pure particulate carbon and hydrogen gas. The pure carbon is removed as a clan product and most of the hydrogen-rich gas is returned to the coal hydrogenator. The two basic steps are than coal hydrogasification in a hydropyrolysis reactor (HPR) and methane decomposition in a methane pyrolysis reactor (MPR). 6 refs., 3 figs., 2 tabs.

Steinberg, M.

1991-05-01

332

Process for derivatizing carbon nanotubes with diazonium species  

NASA Technical Reports Server (NTRS)

The invention incorporates new processes for the chemical modification of carbon nanotubes. Such processes involve the derivatization of multi- and single-wall carbon nanotubes, including small diameter (ca. 0.7 nm) single-wall carbon nanotubes, with diazonium species. The method allows the chemical attachment of a variety of organic compounds to the side and ends of carbon nanotubes. These chemically modified nanotubes have applications in polymer composite materials, molecular electronic applications and sensor devices. The methods of derivatization include electrochemical induced reactions thermally induced reactions (via in-situ generation of diazonium compounds or pre-formed diazonium compounds), and photochemically induced reactions. The derivatization causes significant changes in the spectroscopic properties of the nanotubes. The estimated degree of functionality is ca. 1 out of every 20 to 30 carbons in a nanotube bearing a functionality moiety. Such electrochemical reduction processes can be adapted to apply site-selective chemical functionalization of nanotubes. Moreover, when modified with suitable chemical groups, the derivatized nanotubes are chemically compatible with a polymer matrix, allowing transfer of the properties of the nanotubes (such as, mechanical strength or electrical conductivity) to the properties of the composite material as a whole. Furthermore, when modified with suitable chemical groups, the groups can be polymerized to form a polymer that includes carbon nanotubes ##STR00001##.

Tour, James M. (Inventor); Bahr, Jeffrey L. (Inventor); Yang, Jiping (Inventor)

2007-01-01

333

Comparison of physicochemical properties of nitrogen-enriched activated carbons prepared by physical and chemical activation of brown coal  

Microsoft Academic Search

Nitrogen-enriched active carbon has been obtained from Polish brown coal from the 'Konin' colliery. The process of ammoxidation by a mixture of ammonia and air at the ratio of 1:3 has been performed at two temperatures (300 and 350°C) at different stages of the production, that is, at that of precursor, char, and active carbon. It has been shown that

Piotr Nowicki; Robert Pietrzak; Helena Wachowska

2008-01-01

334

Pyrolysis of scrap tires and conversion of chars to activated carbon  

SciTech Connect

The primary objective of this work was to demonstrate the conversion of scrap tires to activated carbon. The authors have been successful in this endeavor, producing carbons with surface areas greater than 500 m[sup 2]/g and significant micropore volumes. Tire shreddings were pyrolyzed in batch reactors, and the pyrolysis chars activated by reaction with superheated steam. Solid products of pyrolysis and activation were studied with nitrogen adsorption techniques. They find that the porosity development during steam activation of tire pyrolysis char is similar to that reported for various other chars. A maximum in micropore volume is observed as a function of conversion, but the total surface area increases monotonically with conversion. They suggest that the activation process consists of micropore formation, followed by pore enlargement. The process conditions used in this study are a good starting point from which to optimize a process to convert tires to activated carbon.

Merchant, A.A.; Petrich, M.A. (Northwestern Univ., Evanston, IL (United States). Dept. of Chemical Engineering)

1993-08-01

335

Novel electro-fenton approach for regeneration of activated carbon.  

PubMed

An electro-Fenton-based method was used to promote the regeneration of granular activated carbon (GAC) previously adsorbed with toluene. Electrochemical regeneration experiments were carried out using a standard laboratory electrochemical cell with carbon paste electrodes and a batch electrochemical reactor. For each system, a comparison was made using FeSO4 as a precursor salt in solution (homogeneous system) and an Fe-loaded ion-exchange resin (Purolite C-100, heterogeneous system), both in combination with electrogenerated H2O2 at the GAC cathode. In the two cases, high regeneration efficiencies were obtained in the presence of iron using appropriate conditions of applied potential and adsorption-polarization time. Consecutive loading and regeneration cycles of GAC were performed in the reactor without great loss of the adsorption properties, only reducing the regeneration efficiency by 1% per cycle during 10 cycles of treatment. Considering that, in the proposed resin-containing process, the use of Fe salts is avoided and that GAC cathodic polarization results in efficient cleaning and regeneration of the adsorbent material, this novel electro-Fenton approach could constitute an excellent alternative for regenerating activated carbon when compared to conventional methods. PMID:23782426

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

2013-07-16

336

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

PubMed

Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs. PMID:20704238

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

2010-08-15

337

Numerical simulation of isothermal chemical vapor infiltration process in fabrication of carbon-carbon composites by finite element method  

Microsoft Academic Search

The chemical vapor infiltration process in fabrication of carbon-carbon composites is highly inefficient and requires long\\u000a processing time. These limitations add considerably to the cost of fabrication and restrict the application of this material.\\u000a Efforts have been made to study the CVI process in fabrication of carbon-carbon composites by computer simulation and predict\\u000a the process parameters, density, porosity, etc. According

Kezhi Li; Hejun Li; Kaiyu Jiang; Xianghui Hou

2000-01-01

338

Adsorption capacity of powdered activated carbon for 3,5-dichlorophenol in activated sludge.  

PubMed

The objectives of this study were to evaluate the performance of powdered activated carbon treatment (PACT) process based on the adsorption capacity of powdered activated carbon (PAC) in activated sludge and the effect of dissolved organic substances in activated sludge on the adsorption capacity of PAC. The DCP adsorption capacity of three PACs originated from different raw materials (coal, soft coal and sawdust) in activated sludge were 29%, 34% and 17% of that of new PAC, respectively. The performance of PACT process for shock loading of 3,5-dichlorophenol (3,5-DCP) was different among PACs in spite of the same adsorption capacity in new PAC. The performance of PACT process for removal of DCP is dependent not on the adsorption capacity of new PAC but on the adsorption capacity of PAC in the aeration tank. Dissolved organic matter (DOM) with molecular weight smaller than 50kDa did not affect the adsorption capacity of PAC for 3,5-DCP in the activated sludge reactor. DOM with molecular weight larger than 50kDa and biofilm developed on the surface of PAC seemed to be responsible for the decreased adsorption capacity of PAC for the DCP. PMID:15504483

Widjaja, Tri; Miyata, Tomonori; Nakano, Yoichi; Nishijima, Wataru; Okada, Mitsumasa

2004-12-01

339

Preparation and characterization of activated carbon from waste biomass.  

PubMed

Lignocellulosic materials are good and cheap precursors for the production of activated carbon. In this study, activated carbons were prepared from the pyrolysis of soybean oil cake at 600 and 800 degrees C by chemical activation with K(2)CO(3) and KOH. The influence of temperature and type of chemical reagents on the porosity development was investigated and discussed. K(2)CO(3) was found more effective than KOH as a chemical reagent under identical conditions in terms of both porosity development and yields of the activated carbons. The maximum surface area (1352.86 m(2)g(-1)) was obtained at 800 degrees C with K(2)CO(3) activation which lies in the range of commercial activated carbons. Elemental analyses of the activated carbons indicate insignificant sulphur content for all activated carbons. The ash and sulphur contents of the activated carbons obtained with chemical activation by K(2)CO(3) were lower than those by chemical activation with KOH. PMID:19022575

Tay, Turgay; Ucar, Suat; Karagöz, Selhan

2009-06-15

340

Removal of Toxic Chemicals from Water with Activated Carbon  

Microsoft Academic Search

Activated carbon was effective in removing fish toxicants and anesthetics from water solutions. Its capacity to adsorb 3-trifluoromethyl-4-nitrophenol (TFM), antimycin, Noxfish (5% rotenone), Dibrom, juglone, MS-222, and benzocaine ranged from 0.1 to 64 mg per gram of carbon. The adsorptive capacity (end point considered as a significant discharge) of activated carbon for removal of TFM was determined at column depths

Verdel K. Dawson; Leif L. Marking; Terry D. Bills

1976-01-01

341

TEMPERATURE DEPENDENCE ON ACTIVATED CARBON ADSORPTION OF ATRAZINE  

Microsoft Academic Search

This study examined the effect of temperature on atrazine adsorption in water by activated carbon. Freundlich isotherms for atrazine were determined in batch contactors, using 100-µm activated carbon and atrazine in organic-free laboratory water, as well as treated river water with 2.4 mg\\/L dissolved organic carbon (DOC). Experiments were conducted at four different temperatures (5, 12, 25 and 35oC), with

Gen-Shuh Wang

2003-01-01

342

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

PubMed

Corn stalks char from fast pyrolysis was activated by physical and chemical activation process in a fluidized bed reactor. The structure and morphology of the carbons were characterized by N2 adsorption and SEM. Effects of activation time and activation agents on the structure of activation carbon were investigated. The physically activated carbons with CO2 have BET specific surface area up to 880m(2)/g, and exhibit microporous structure. The chemically activated carbons with H3PO4 have BET specific surface area up to 600m(2)/g, and exhibit mesoporous structure. The surface morphology shows that physically activated carbons exhibit fibrous like structure in nature with long ridges, resembling parallel lines. Whereas chemically activated carbons have cross-interconnected smooth open pores without the fibrous like structure. PMID:24974241

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

2014-09-01

343

Characteristics of activated carbon produced from biosludge and its use in wastewater post-treatment.  

PubMed

Experimental research into the bench-scale production of activated carbon from waste-activated sludge from water purification, sawdust, peat, and their mixtures, by carbonisation and activation was undertaken. The research work was carried out to determine possible methods of production of cheap activated carbon from local raw materials and to use it in water purification technology. Along with the samples produced, several commercial activated carbons (namely RB-1, F 100, CA (adsorbent from military gas masks), BAY (product of the USSR)) were tested to compare adsorption properties in the adsorption of phenols, xylidines, amines, methylene blue and molasses. It has been found that the activated carbon produced from waste biosludge was of higher quality than that produced from either sawdust or peat, and performed similarly to RB-1 and F100 in adsorption tests. It was also determined that the activated carbon produced from biosludge could possibly be used in the post-treatment of wastewater. Residual sludge from the biological treatment of the wastewater from the purification of oil-shale in the chemical processing industry could cover up to 80% of the need for activated carbon. Some of this activated carbon could be used in the post-treatment of the same water, adsorbing polyalcaline phenols from the initial content of 4 mg l-1 to the demanded level of 1 mg l-1. PMID:11349382

Pikkov, L; Kallas, J; Rüütmann, T; Rikmann, E

2001-02-01

344

Pulsed carbon-plasma source for production processes  

SciTech Connect

This paper describes a pulsed electric-arc accelerator or carbon plasma of the end-window type that produces highstrength diamond-like coatings on cutting tools and parts of process equipment. The average energy of carbon ions, which varies in the range of 40-80 eV according to the operating mode of the source, is measured. The average condensation rate is 15 um/h. The space characteristics of the pulsed plasma beam are measured and the dependence of the stability of the production parameters of the deposition process on the operating reserve of the source is investigated.

Maslov, A.I.; Chistyakov, Y.D.; Dmitriev, G.K.

1985-12-01

345

Removal of Formaldehyde by Activated Carbons Containing Amino Groups  

Microsoft Academic Search

Formaldehyde has been used for disinfection and antisepsis in hospitals due to its bactericidal action, but it is toxic to humans. Hence, we developed adsorbates for the removal of formaldehyde. The adsorbate was prepared by the amination of an activated carbon surface. The removal efficiency and the adsorption mechanism of formaldehyde onto the aminated activated carbon were studied. The concentrated

Seiki Tanada; Naohito Kawasaki; Takeo Nakamura; Mamiko Araki; Masahiko Isomura

1999-01-01

346

Preparation of nitrogen-enriched activated carbons from brown coal  

SciTech Connect

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

Robert Pietrzak; Helena Wachowska; Piotr Nowicki [Adam Mickiewicz University, Poznan (Poland). Laboratory of Coal Chemistry and Technology, Faculty of Chemistry

2006-05-15

347

Activated carbon catalytic ozonation of oxamic and oxalic acids  

Microsoft Academic Search

The oxidation of hazardous organic compounds leads to the formation of several by-products, being oxalic acid and oxamic acid final oxidation products refractory to ozonation. The present work aimed to study the ozonation of those carboxylic acids in the presence of activated carbon at different solution pH. For comparative purposes, experiments of adsorption on activated carbon, ozonation, and ozonation in

P. C. C. Faria; J. J. M. Órfão; M. F. R. Pereira

2008-01-01

348

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

PubMed

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

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

2013-04-01

349

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

SciTech Connect

Direct mineral carbonation was investigated as a process to convert gaseous CO[2] into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg[2]SiO[4]) or serpentine [Mg[3]Si[2]O[5](OH)[4

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

2002-05-01

350

Ozone Removal by Filters Containing Activated Carbon: A Pilot Study  

SciTech Connect

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.

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

2009-09-01

351

PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS  

SciTech Connect

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

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

2004-08-31

352

Carbon processing in the Kolyma River Watershed and the role it plays in CO2 outgassing  

NASA Astrophysics Data System (ADS)

The Kolyma River watershed in Northeast Siberia is the largest watershed underlain by continuous permafrost, storing vast amounts of organic carbon and nutrients, which if thawed will become available to microbial processing or transport downstream. Understanding the internal hydrological processes and outgassing across large Arctic river watersheds is crucial if we are to better refine estimates of GHG emissions. Previous conceptual models treated waterways as simple pipes, transporting water from land to ocean without internal processing but current research makes it evident that we must acknowledge them as possible active processors. In July and August 2010, a survey spanning 260 km of the Kolyma River Watershed was conducted to examine the rates of carbon processing in a diverse set of subwatersheds. A total of 23 subwatersheds (eleven streams, and twelve rivers) and nine mainstem locations were sampled at which water samples were collected for measurements of partial pressure of Carbon dioxide (pCO2), dissolved organic carbon (DOC), chromophoric dissolved organic matter (CDOM) and biological oxygen demand (BOD). Spatially, pCO2 concentrations decrease along flowpaths from small streams to the Ocean with the greatest variation between small streams and large rivers. Measurements of DOC concentrations and bioavailability indicate small streams are higher in the total amount and lability of DOC compared to larger tributaries. The results of this study suggest the headwater streams in the Kolyma River watershed are actively processing carbon during the summer at a more significant rate compared to larger tributaries and the Kolyma mainstem. Understanding the relationship between watershed size and carbon processing is critical for predicting how future warming will likely impact the Arctic carbon cycle. This study is part of the Polaris Project, an NSF-funded undergraduate field program based out of the Northeast Science Station in Cherskiy, Northeast Siberia (www.thepolarisproject.org).

Denfeld, B. A.; Frey, K. E.; Bulygina, E. B.; Drake, T.; Holmes, R. M.; Schade, J. D.; Sobczak, W. V.; Zimov, N.

2010-12-01

353

Utilization of Thermal Analysis to Establish the Optimal Conditions for Regeneration of Activated Carbons  

Microsoft Academic Search

Thermoanalytical methods (TG, DTG and DTA) were used to determine the temperature interval (140–350C) in which p-nitroaniline undergoes thermal desorption from the surface of activated carbons obtained from the shells of oxidized plum\\u000a stones and impregnated with aqueous solutions of Cu, Fe and Ti salts, which simulate the processes of activated carbon regeneration.\\u000a It was established that the impregnation of

I. Dranca; T. Lupascu; K. Vogelsang; L. Monahova

2001-01-01

354

Removal of Nitrate from Water by Adsorption onto Zinc Chloride Treated Activated Carbon  

Microsoft Academic Search

Adsorption study with untreated and zinc chloride (ZnCl2) treated coconut granular activated carbon (GAC) for nitrate removal from water has been carried out. Untreated coconut GAC was treated with ZnCl2 and carbonized. The optimal conditions were selected by studying the influence of process variables such as chemical ratio and activation temperature. Experimental results reveal that chemical weight ratio of 200%

Amit Bhatnagar; Minkyu Ji; Woosik Jung; Giehyeon Lee; Heejun Suk; Booki Min

2008-01-01

355

Arsenate removal from water using Fe 3O 4-loaded activated carbon prepared from waste biomass  

Microsoft Academic Search

A novel process for the preparation of Fe3O4-loaded activated carbon (MY) was developed using waste biomass. The key point of the synthetic strategy was that the carbonization, activation and Fe3O4 loading were accomplished simultaneously. The low-cost composite was characterized and used as an adsorbent for arsenate removal from water. The results showed that the Fe3O4 particles were uniformly deposited on

Zhengang Liu; Fu-Shen Zhang; Ryo Sasai

2010-01-01

356

Production of activated carbons from coffee endocarp by CO 2 and steam activation  

Microsoft Academic Search

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

João M. Valente Nabais; Pedro Nunes; Peter J. M. Carrott; M. Manuela L. Ribeiro Carrott; A. Macías García; M. A. Díaz-Díez

2008-01-01

357

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

PubMed

Optimizing the production of microporous activated carbon from waste palm shell was done by applying experimental design methodology. The product, palm shell activated carbon was tested for removal of SO2 gas from flue gas. The activated carbon production was mathematically described as a function of parameters such as flow rate, activation time and activation temperature of carbonization. These parameters were modeled using response surface methodology. The experiments were carried out as a central composite design consisting of 32 experiments. Quadratic models were developed for surface area, total pore volume, and microporosity in term of micropore fraction. The models were used to obtain the optimum process condition for the production of microporous palm shell activated carbon useful for SO2 removal. The optimized palm shell activated carbon with surface area of 973 m(2)/g, total pore volume of 0.78 cc/g and micropore fraction of 70.5% showed an excellent agreement with the amount predicted by the statistical analysis. Palm shell activated carbon with higher surface area and microporosity fraction showed good adsorption affinity for SO2 removal. PMID:18952414

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

2009-02-01

358

Hydrothermal carbonization: process water characterization and effects of water recirculation.  

PubMed

Poplar wood chips were treated hydrothermally and the increase of process efficiency by water recirculation was examined. About 15% of the carbon in the biomass was dissolved in the liquid phase when biomass was treated in de-ionized water at 220 °C for 4 h. The dissolved organic matter contained oxygen and was partly aerobically biodegradable. About 30-50% of the total organic carbon originated from organic acids. A polar and aromatic fraction was extracted and a major portion of the organic load was of higher molecular weight. By process water recirculation organic acids in the liquid phase concentrated and catalyzed dehydration reactions. As a consequence, functional groups in hydrothermally synthesized coal declined and dewaterability was enhanced. Recirculated reactive substances polymerized and formed additional solid substance. As a result, carbon and energetic yields of the produced coal rose to 84% and 82%, respectively. PMID:23792664

Stemann, Jan; Putschew, Anke; Ziegler, Felix

2013-09-01

359

DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS  

Microsoft Academic Search

The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. These carbon products include materials used in metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. A process has been developed which results

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

2005-01-01

360

The transport properties of activated carbon fibers  

SciTech Connect

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

di Vittorio, S.L. (Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (USA)); Dresselhaus, M.S. (Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (USA) Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (USA)); Endo, M. (Department of Electrical Engineering, Faculty of Engineering, Shinshu University, Nagano 380, (Japan)); Issi, J.; Piraux, L.; Bayot, V. (Unite de Physico-Chimie et de Physique des Materiaux, Universite Catholique de Louvain, Louvain-la-Neuve, (Belgium))

1991-04-01

361

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

PubMed

Carbon nanotubes (CNTs) have shown great promise as high performance materials for adsorbing priority pollutants from water and wastewater. This study compared uptake of two contaminants of interest in drinking water treatment (atrazine and trichloroethylene) by nine different types of carbonaceous adsorbents: three different types of single walled carbon nanotubes (SWNTs), three different sized multi-walled nanotubes (MWNTs), two granular activated carbons (GACs) and a powdered activated carbon (PAC). On a mass basis, the activated carbons exhibited the highest uptake, followed by SWNTs and MWNTs. However, metallic impurities in SWNTs and multiple walls in MWNTs contribute to adsorbent mass but do not contribute commensurate adsorption sites. Therefore, when uptake was normalized by purity (carbon content) and surface area (instead of mass), the isotherms collapsed and much of the CNT data was comparable to the activated carbons, indicating that these two characteristics drive much of the observed differences between activated carbons and CNT materials. For the limited data set here, the Raman D:G ratio as a measure of disordered non-nanotube graphitic components was not a good predictor of adsorption from solution. Uptake of atrazine by MWNTs having a range of lengths and diameters was comparable and their Freundlich isotherms were statistically similar, and we found no impact of solution pH on the adsorption of either atrazine or trichloroethylene in the range of naturally occurring surface water (pH = 5.7-8.3). Experiments were performed using a suite of model aromatic compounds having a range of ?-electron energy to investigate the role of ?-? electron donor-acceptor interactions on organic compound uptake by SWNTs. For the compounds studied, hydrophobic interactions were the dominant mechanism in the uptake by both SWNTs and activated carbon. However, comparing the uptake of naphthalene and phenanthrene by activated carbon and SWNTs, size exclusion effects appear to be more pronounced with activated carbon materials, perhaps due to smaller pore sizes or larger adsorption surface areas in small pores. PMID:22743805

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

2012-07-27

362

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

363

Studies relevant to the catalytic activation of carbon monoxide  

SciTech Connect

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.

Ford, P.C.

1992-06-04

364

Carbon nanotube growth activated by quantum-confined silicon nanocrystals  

NASA Astrophysics Data System (ADS)

We report on the use of silicon nanocrystals (Si-ncs) to activate nucleation and growth of carbon nanotubes (CNTs) without using any metal catalyst. Si-ncs with different surface characteristics have been exposed to the same CH4 low-pressure plasma treatment producing quite different results. Specifically, Si-ncs prepared by laser ablation in water have contributed to the formation of micrometre-sized silicon spherical particles. On the other hand, Si-ncs prepared by electrochemical etching did not induce any specific growth while the third type of Si-ncs, prepared by electrochemical etching and treated by a laser fragmentation process, induced the growth of multi-walled CNTs. The different outcomes of the same plasma process are attributed to the diverse surface features presented by the Si-ncs.

Mariotti, D.; Švr?ek, V.; Mathur, A.; Dickinson, C.; Matsubara, K.; Kondo, M.

2013-03-01

365

ESR study of activated carbon fibers: preliminary results  

SciTech Connect

We have carried out Electron Spin Resonance (ESR) measurements on activated carbon fibers (ACF) with specific surface areas (SSA) of 3000 and 2000 m[sup 2]/g. The ESR spectrum of ACF fibers in air is extremely broad (500 to 1000 Gauss), and the spin susceptibility decreases rapidly with decreasing specific surface area. Also measured was the ESR signal of the desorbed fibers in vacuum. As a result of desorption, the broad peak decreases slightly in intensity, and a narrow ([approx]65 Gauss at room temperature) peak appears. We report results on the temperature dependence of both peaks. The narrow peak is interpreted as due to spins associated with dangling bonds, whereas we attribute the broad peak to the conduction carrier spins which is broadened by the boundary scattering process ([ital T][sub 1] contribution) and the dipolar broadening process ([ital T][sub 2] contribution) associated with the dangling bond spins.

di Vittorio, S.L. (Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)); Nakayama, A.; Enoki, T. (Department of Chemistry, Tokyo Institute of Technology, Ookayama, Tokyo (Japan)); Dresselhaus, M.S. (Department of Electrical Engineering and Computer Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)); Endo, M. (Department of Electrical Engineering, Faculty of Engineering Shinshu University, Nagano 380 (Japan)); Shindo, N. (Osaka Gas Company, Central Research Laboratory, Torishima, Konohana-ku, Osaka 554 (Japan))

1993-09-01

366

Activation-free printed carbon nanotube field emitters  

NASA Astrophysics Data System (ADS)

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.

Kim, Yong C.; Hur, Jung N.; Kim, Il H.; Park, Sang H.; Jung, Tae W.; Kim, Do Y.; Kim, Ha J.; Cha, Seung N.; Han, In T.; Kim, Jong M.; Kim, Young H.

2011-10-01

367

Preparation and Characterization of Activated Carbon Fiber from Paper  

NASA Astrophysics Data System (ADS)

Activated carbon fibers (ACFS) with surface area of 1388 m2/g prepared from paper by chemical activation with KOH has been utilized as the adsorbent for the removal of methylene blue from aqueous solution. The experimental data were analyzed by Langmuir and Freundlich models of adsorption. The effects of pH value on the adsorption capacity of ACFS were also investigated. The rates of adsorption were found to conform to the kinetic model of Pseudo-second-order equation with high values of the correlation coefficients (R>0.998). The Langmuir isotherm was found to fit the experimental data better than the Feundlich isotherm over the whole concentration range. Maximum adsorption capacity of 520 mg/g at equilibrium was achieved. It was found that pH played a major role in the adsorption process, higher pH value favored the adsorption of MB.

Zhang, Zong-jian; Li, Jia; Sun, Fu-sheng; Ng, Dickon H. L.; Kwong, Fung-luen; Liu, Shi-quan

2011-02-01

368

Chemical vapor deposition and infiltration processes of carbon materials  

Microsoft Academic Search

The chemical vapor deposition (CVD) and the chemical vapor infiltration (CVI) processes of carbon materials are reviewed starting from the historical aspects and including the latest developments in the preparation of C\\/C composites. Our presentation is based on an analysis of the different types of reactors, of the composite materials with different types of pyrocarbon as matrices and a comparison

P Delhaes

2002-01-01

369

Plasma processing of carbon-containing technical aggregations and wastes  

Microsoft Academic Search

The plasma gasification of technical aggregations is experimentally studied using the utilization of solid domestic wastes as an example. A shaft electric furnace is described, and the experimental and calculated data are analyzed and compared. The high-temperature gasification of carbon-containing wastes is shown to be a promising process.

V. S. Cherednichenko; A. S. An'shakov; V. A. Faleev; A. A. Danilenko

2008-01-01

370

Plasma processing of carbon-containing technical aggregations and wastes  

Microsoft Academic Search

The plasma gasification of technical aggregations is experimentally studied using the utilization of solid domestic wastes\\u000a as an example. A shaft electric furnace is described, and the experimental and calculated data are analyzed and compared.\\u000a The high-temperature gasification of carbon-containing wastes is shown to be a promising process.

V. S. Cherednichenko; A. S. An’shakov; V. A. Faleev; A. A. Danilenko

2008-01-01

371

Regression analysis study on the carbon dioxide capture process  

Microsoft Academic Search

Research on amine-based carbon dioxide (CO) capture has mainly focused on improving the effectiveness and efficiency of the CO capture process. The objective of our work is to explore relationships among key parameters that affect the CO production rate. From a survey of relevant literature, we observed that the significant parameters influencing the CO production rate include the reboiler heat

Q. Zhou; Christine W. Chan; P. Tontiwachiwuthikul

2008-01-01

372

Inner-tubular physicochemical processes of carbon nanotubes  

Microsoft Academic Search

Nanosized inner cavities of carbon nanotubes (CNTs) afford quasi-one-dimensional (1D) confined space, in which materials adsorbed or filled are of reactivity greatly different from the materials adsorbed on a planar surface and quite a number of curious physicochemical processes will possibly occur. In other words, 1D CNT nanochannels may serve as \\

YANG Quanhong; L I Lixiang; CHENG Huiming

2003-01-01

373

Process for the manufacture of enriched pitches and carbon fibers  

Microsoft Academic Search

This patent describes an improved process for the production of carbon fibers. It comprises: treating a petroleum pitch in a system comprising wiped-film evaporator and a means for recovering enriched pitch to obtain an enriched pitch; delivering the enriched pitch to the inlet of the means for recovering enriched pitch at a pressure equivalent to a vertical distance between the

D. C. Berkebile; D. M. Lee; L. D. Veneziano; J. L. Lauer; R. E. Booth; W. P. Hettinger

1991-01-01

374

Comparison of catalytic ozonation of phenol by activated carbon and manganese-supported activated carbon prepared from brewing yeast  

Microsoft Academic Search

Activated carbon (AC) was prepared using brewing yeast as precursor by chemical activation and manganese was supported on\\u000a activated carbon (Mn\\/AC) by adsorption-activation method. The characterizations of prepared AC and Mn\\/AC and their performance\\u000a as ozonation catalysts was tested. The results indicated that the crystalline phase of supported manganese was MnO. The total\\u000a BET surface areas of prepared AC and

Guiping Wu; Tae-seop Jeong; Chan-Hee Won; Longzhe Cui

2010-01-01

375

DETERMINATION OF DIOXIN LEVELS IN CARBON REACTIVATION PROCESS EFFLUENT STREAMS  

EPA Science Inventory

A preliminary study was performed to evaluate the potential formation and persistence of tetrachlorodibenzo-p-dioxins (TCDDs) and tetrachlorodibenzo furans (TCDFs) in the effluent streams of a fluidized bed system used for thermal reactivation of granular activated carbon (GAC) t...

376

DISCOVERY AND ELIMINATION OF DIOXINS FROM A CARBON REACTIVATION PROCESS  

EPA Science Inventory

In a project done to ensure an environmentally acceptable granular activated carbon (GAC) adsorption and reactivation system--to be sure that chlorinated dibenzo-p-dioxins (CDD's) and chlorinated dibenzo furans (CDF's) and combustion would not present problems--results from a GAC...

377

Grain-based activated carbons for natural gas storage.  

PubMed

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

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

2010-03-01

378

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

SciTech Connect

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 m{sup 2}/g showed a larger amount of adsorption as compared to multiwalled nanotubes (commercial) with a surface area of 119.68 m{sup 2}/g. This study als indicated that there is a direct correlation between the amounts of hydrogen adsorbed an surface area of the carbon materials under the conditions studied and that the adsorption significant at 77 K.

Sanip, S. M.; Saidin, M. A. R.; Aziz, M.; Ismail, A. F. [Membrane Research Unit, Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor (Malaysia)

2010-03-11

379

Process modeling for carbon-phenolic nozzle materials  

NASA Technical Reports Server (NTRS)

A thermochemical model based on the SINDA heat transfer program is developed for carbon-phenolic nozzle material processes. The model can be used to optimize cure cycles and to predict material properties based on the types of materials and the process by which these materials are used to make nozzle components. Chemical kinetic constants for Fiberite MX4926 were determined so that optimization of cure cycles for the current Space Shuttle Solid Rocket Motor nozzle rings can be determined.

Letson, Mischell A.; Bunker, Robert C.; Remus, Walter M., III; Clinton, R. G.

1989-01-01

380

CCN activation of pure and coated carbon black particles.  

PubMed

The CCN (cloud condensation nucleus) activation of pure and coated carbon black particles was investigated using the University of Vienna cloud condensation nuclei counter (Giebl, H.; Berner, A.; Reischl, G.; Puxbaum, H.; Kasper-Giebl, A.; Hitzenberger, R. J. Aerosol Sci. 2002, 33, 1623-1634). The particles were produced by nebulizing an aqueous suspension of carbon black in a Collison atomizer. The activation of pure carbon black particles was found to require higher supersaturations than predicted by calculations representing the particles as insoluble, wettable spheres with mobility equivalent diameter. To test whether this effect is an artifact due to heating of the light-absorbing carbon black particles in the laser beam, experiments at different laser powers were conducted. No systematic dependence of the activation of pure carbon black particles on laser power was observed. The observations could be modeled using spherical particles and an effective contact angle of 4-6 degrees of water at their surface. The addition of a small amount of NaCl to the carbon black particles (by adding 5% by mass NaCl to the carbon black suspension) greatly enhanced their CCN efficiency. The measured CCN efficiencies were consistent with Kohler theory for particles consisting of insoluble and hygroscopic material. However, coating the carbon black particles with hexadecanol (a typical film-forming compound with one hydrophobic and one hydrophilic end) efficiently suppressed the CCN activation of the carbon black particles. PMID:16572779

Dusek, U; Reischl, G P; Hitzenberger, R

2006-02-15

381

The use of steam and CO 2 as activating agents in the preparation of activated carbons  

Microsoft Academic Search

Four series of activated carbon have been prepared from carbonized olive stones. One of them, series D, was prepared using carbon dioxide as activating agent, and the other three, series AV, W, and H, with water vapor under different experimental conditions. Two of the series, D and H, were prepared in such a way that the gasification rate for both

F. Rodríguez-Reinoso; M. Molina-Sabio; M. T. González

1995-01-01

382

Tetracycline removal from water by adsorption/bioadsorption on activated carbons and sludge-derived adsorbents.  

PubMed

The objective of this study was to analyze the behavior of activated carbons with different chemical and textural natures in the adsorption of three tetracyclines (TCs) (tetracycline, oxytetracycline, and chlortetracycline). We also assessed the influence of the solution pH and ionic strength on the adsorption of these compounds and studied their removal by the combined use of microorganisms and activated carbon (bioadsorption). Sludge-derived materials were also used to remove TC from water. The capacity of these materials to adsorb TC was very high and was much greater than that of commercial activated carbon. This elevated adsorption capacity (512.1-672.0 mg/g) is explained by the high tendency of TC to form complex ions with some of the metal ions present in these materials. The medium pH and presence of electrolytes considerably affected TCs adsorption on commercial activated carbon. These results indicate that electrostatic adsorbent-adsorbate interactions play an important role in TC adsorption processes when conducted at pH values that produce TC deprotonation. The presence of bacteria during the TCs adsorption process decreases their adsorption/bioadsorption on the commercial activated carbon, weakening interactions between the adsorbate and the microfilm formed on the carbon surface. The adsorptive capacity was considerably lower in dynamic versus static regime, attributable to problems of TC diffusion into carbon pores and the shorter contact time between adsorbate and adsorbent. PMID:24140483

Rivera-Utrilla, José; Gómez-Pacheco, Carla V; Sánchez-Polo, Manuel; López-Peñalver, Jesús J; Ocampo-Pérez, Raúl

2013-12-15

383

Production of Activated Carbon from Jojoba Seed Residue by Chemical Activation Residue Using a Static Bed Reactor  

Microsoft Academic Search

The production of chemically activated carbon from Jojoba seed residue was experimentally investigated using a laboratory-scale static bed reactor. The effects of process variables such as activation time, activation temperature, particle size, chemical reagents (KCl, ZnCl2 and H3PO4) and impregnation ratio on adsorption capacity of activated Jojoba seed residue were studied. The highest iodine number and yield were obtained by

Muhammad Tawalbeh; Mamdouh A. Allawzi; Munther I. Kandah

2005-01-01

384

Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons  

PubMed Central

An activated carbon, CarbochemTM—PS230, was modified by chemical and thermal treatment in flow of H2, in order to evaluate the influence of the activated carbon chemical characteristics in the adsorption of the catechol. The catechol adsorption in aqueous solution was studied along with the effect of the pH solution in the adsorption process of modified activated carbons and the variation of immersion enthalpy of activated carbons in the aqueous solutions of catechol. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and pH 7, 9 and 11 in order to evaluate the adsorption value above and below that of the catechol pKa. The adsorption capacity of carbons increases when the solution pH decreases. The retained amount increases slightly in the reduced carbon to maximum adsorption pH and diminishes in the oxidized carbon. Similar conclusions are obtained from the immersion enthalpies, whose values increase with the solute quantity retained. In granular activated carbon (CAG), the immersion enthalpies obtained are between 21.5 and 45.7 J·g?1 for catechol aqueous solutions in a range of 20 at 1500 mg·L?1.

Moreno-Pirajan, Juan Carlos; Blanco, Diego; Giraldo, Liliana

2012-01-01

385

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

SciTech Connect

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

Varma, R.; Nandi, S.P.

1991-01-01

386

Changes in surface chemistry of activated carbons by wet oxidation  

Microsoft Academic Search

A series of activated carbons with different degrees of activation were oxidized with H2O2, (NH4)2S2O8 and HNO3 in order to introduce different oxygen surface complexes. Changes in the surface chemistry of the activated carbons after their oxidizing treatments were studied by different techniques including temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectroscopy (FTIR), titrations with HCl and

C Moreno-Castilla; M. V López-Ramón; F Carrasco-Mar??n

2000-01-01

387

Preparation and characterization of activated carbon from waste biomass  

Microsoft Academic Search

Lignocellulosic materials are good and cheap precursors for the production of activated carbon. In this study, activated carbons were prepared from the pyrolysis of soybean oil cake at 600 and 800°C by chemical activation with K2CO3 and KOH. The influence of temperature and type of chemical reagents on the porosity development was investigated and discussed. K2CO3 was found more effective

Turgay Tay; Suat Ucar; Selhan Karagöz

2009-01-01

388

Exploration of the role of heat activation in enhancing serpentine carbon sequestration reactions.  

PubMed

As compared with other candidate carbon sequestration technologies, mineral carbonation offers the unique advantage of permanent disposal via geologically stable and environmentally benign carbonates. The primary challenge is the development of an economically viable process. Enhancing feedstock carbonation reactivity is key. Heat activation dramatically enhances aqueous serpentine carbonation reactivity. Although the present process is too expensive to implement, the materials characteristics and mechanisms that enhance carbonation are of keen interest for further reducing cost. Simultaneous thermogravimetric and differential thermal analysis (TGA/DTA) of the serpentine mineral lizardite was used to isolate a series of heat-activated materials as a function of residual hydroxide content at progressively higher temperatures. Their structure and composition are evaluated via TGA/DTA, X-ray powder diffraction (including phase analysis), and infrared analysis. The meta-serpentine materials that were observed to form ranged from those with longer range ordering, consistent with diffuse stage-2 like interlamellar order, to an amorphous component that preferentially forms at higher temperatures. The aqueous carbonation reaction process was investigated for representative materials via in situ synchrotron X-ray diffraction. Magnesite was observed to form directly at 15 MPa CO2 and at temperatures ranging from 100 to 125 degrees C. Carbonation reactivity is generally correlated with the extent of meta-serpentine formation and structural disorder. PMID:15669355

McKelvy, Michael J; Chizmeshya, Andrew V G; Diefenbacher, Jason; Béarat, Hamdallah; Wolf, George

2004-12-15

389

Exploration of the Role of Heat Activation in Enhancing Serpentine Carbon Sequestration Reactions  

SciTech Connect

As compared with other candidate carbon sequestration technologies, mineral carbonation offers the unique advantage of permanent disposal via geologically stable and environmentally benign carbonates. The primary challenge is the development of an economically viable process. Enhancing feedstock carbonation reactivity is key. Heat activation dramatically enhances aqueous serpentine carbonation reactivity. Although the present process is too expensive to implement, the materials characteristics and mechanisms that enhance carbonation are of keen interest for further reducing cost. Simultaneous thermogravimetric and differential thermal analysis (TGA/DTA) of the serpentine mineral lizardite was used to isolate a series of heat-activated materials as a function of residual hydroxide content at progressively higher temperatures. Their structure and composition are evaluated via TGA/DTA, X-ray powder diffraction (including phase analysis), and infrared analysis. The meta-serpentine materials that were observed to form ranged from those with longer range ordering, consistent with diffuse stage-2 like interlamellar order, to an amorphous component that preferentially forms at higher temperatures. The aqueous carbonation reaction process was investigated for representative materials via in situ synchrotron X-ray diffraction. Magnesite was observed to form directly at 15 MPa CO{sub 2} and at temperatures ranging from 100 to 125 C. Carbonation reactivity is generally correlated with the extent of meta-serpentine formation and structural disorder.

McKelvy, M.J.; Chizmeshya, A.V.G.; Diefenbacher, J.; Bearat, H.; Wolf, G. (ASU)

2005-03-29

390

ACTIVATED CARBON PRODUCTION FROM PYROLYSIS AND STEAM ACTIVATION OF COTTON GIN TRASH  

Microsoft Academic Search

Cotton gin trash (CGT) was used to produce activated carbon via pyrolysis and steam activation. To determine the effect of pyrolysis temperature and time on the properties of activated carbon, optimization of the pyrolysis conditions at temperatures of 600, 700, and 8000C for 30, 45 and 60 minutes were made. Steam activation of the product char was prepared at temperatures

Joan Rollog Hernandez; Sergio C. Capareda; Froilan L. Aquino

391

Adsorption of certain chlorohydrocarbons by commercial active carbons in presence of water vapor  

SciTech Connect

Attempts to develop a sufficiently accurate calculation method for the sorption of moderately adsorbable chlorohydrocarbons by active carbon have failed, even though the method is applicable to weakly adsorbed chlorohydrocarbons. From accumulated experimental data on adsorption of these moderately adsorbed chlorohydrocarbons by active carbons under process conditions, design calculations relating to gas purification plants can be made. The general relationship deduced from the accumulated data can also be used for approximate estimation of adsorption of these moderately adsorbable chlorohydrocarbons in the presence of water vapor by commercial carbons of similar types. 4 references, 4 figures.

Petrova, N.I.; Nikolaev, K.M.

1983-03-10

392

Oxidation of Black Carbon by Biotic and Abiotic Processes  

SciTech Connect

The objectives of this study were to quantify the relative importance of either biotic or abiotic oxidation of biomass-derived black carbon (BC) and to characterize the surface properties and charge characteristics of oxidized particulate BC. We incubated BC and BC-soil mixtures at two different temperatures (30 C and 70 C) with and without microbial inoculation, nutrient additions, or manure amendments for four months. Abiotic processes were more important for oxidation of BC than biotic processes during this short-term incubation, as inoculation with microorganisms did not change any of the measured parameters. Black C incubated at both 30 C and 70 C without microbial activity showed dramatic decreases in pH (in water) from 5.4 to 5.2 and 3.4, as well as increases in cation exchange capacity (CEC at pH 7) by 53% and 538% and in oxygen (O) contents by 4% and 38%, respectively. Boehm titration and Fourier transform infrared (FTIR) spectroscopy suggested that the formation of carboxylic functional groups was the reason for the enhanced CEC during oxidation. The analyses of BC surface properties by X-ray photoelectron spectroscopy (XPS) indicated that the oxidation of BC particles initiated on the surface. Incubation at 30 C only enhanced oxidation on particle surfaces, while oxidation during incubation at 70 C penetrated into the interior of particles. Such short-term oxidation of BC has great significance for the stability of BC in soils as well as for its effects on soil fertility and biogeochemistry.

Cheng, Chih-hsin; Lehmann, Johannes C.; Thies, Janice E.; Burton, Sarah D.; Engelhard, Mark H.

2006-11-01

393

Setup for Visual Observation of Carbon-Nanotube Arc Process  

NASA Technical Reports Server (NTRS)

A simple optical setup has been devised to enable safe viewing of the arc and measurement of the interelectrode gap in a process in which carbon nanotubes are produced in an arc between a catalyst-filled carbon anode and a graphite cathode. This setup can be used for visually guided manual positioning of the anode to maintain the interelectrode gap at a desired constant value, possibly as a low-technology alternative to the automatic position/voltage control described in Automatic Control of Arc Process for Making Carbon Nanotubes (MSC-23134), NASA Tech Briefs, Vol. 28, No. 3 (March 2004), page 51. The optical setup consists mainly of lenses for projecting an image of the arc onto a wall, plus a calibrated grid that is mounted on the wall so that one can measure the superimposed image of the arc. To facilitate determination of the end point of the process, the anode is notched, by use of a file, at the end of the filled portion that is meant to be consumed in the process. As the anode is consumed and the notch comes into view in the scene projected onto the wall, the process operator switches off the arc current.

Scott, Carl D.; Arepalli, Sivaram

2004-01-01

394

Nickel adsorption by sodium polyacrylate-grafted activated carbon.  

PubMed

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

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

2009-11-15

395

Activated carbon fibers and engineered forms from renewable resources  

DOEpatents

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

Baker, Frederick S

2013-02-19

396

Carbon-enriched coal fly ash as a precursor of activated carbons for SO 2 removal  

Microsoft Academic Search

Carbon-enriched coal fly ash was evaluated in this work as a low-cost adsorbent for SO2 removal from stack gases. The unburned carbon in coal fly ash was concentrated by mechanical sieving and vegetal oil agglomeration. The carbon concentrates were activated with steam at 900°C in order to develop porosity onto the samples. The performance of these samples in the SO2

M. T. Izquierdo; B. Rubio

2008-01-01

397

Corrosion activity of carbon plastics and protection of metal power structures in contact with carbon plastics  

Microsoft Academic Search

Methods for assessing the corrosion activity of carbon plastics against metal materials and development of complex anticorrosive\\u000a protection of load-bearing units of structures including carbon plastics in contact with metal materials are considered. Data\\u000a on the electrochemically measured corrosion rates in carbon plastic-metal contact pairs and on the efficiency of separating\\u000a layers (sealants, glass fabrics) are presented. Recommendations on corrosion

S. A. Karimova; T. G. Pavlovskaya; D. V. Chesnokov; L. V. Semenova

2011-01-01

398

Structural sorption characteristics of active carbons obtained from wastes  

SciTech Connect

The high cost and shortage of activated carbons have created a search for cheap adsorbents for treatment or final purification of wastewaters. The structural characteristics of solid wastes from pyrolysis of town wastes (AC-1) and activated sludge from treatment plants (AC-2) were investigated. The possibilities of using them for final purification of wastewaters from phosphate ore treatment plants were examined. The test carbons were inferior to commercial samples in micropore volume, but they were at the same level as the commercial samples or better with regard to the volumes of supermicropores and mesopores and the limiting volume of the adsorption space. It was shown that the carbons studied were close to the commercial carbon AG-3 in adsorption activity. These carbons were suitable for use in final purification of biologically purified wastewaters containing oxidation-resistant organic substance.

Petrova, L.A.; Mukhlenov, I.P.; Tubolkin, A.F.; Galutkina, K.A.

1983-04-01

399

Chemical Reactions in the Processing of Mosi2 + Carbon Compacts  

NASA Technical Reports Server (NTRS)

Hot-pressing of MoSi2 powders with carbon at high temperatures reduces the siliceous grain boundary phase in the resultant compact. The chemical reactions in this process were examined using the Knudsen cell technique. A 2.3 wt pct oxygen MoSi2 powder and a 0.59 wt pct oxygen MoSi2 powder, both with additions of 2 wt pct carbon, were examined. The reduction of the siliceous grain boundary phase was examined at 1350 K and the resultant P(SiO)/P(CO) ratios interpreted in terms of the SiO(g) and CO(g) isobars on the Si-C-O predominance diagram. The MoSi2 + carbon mixtures were then heated at the hot-pressing temperature of 2100 K. Large weight losses were observed and could be correlated with the formation of a low-melting eutectic and the formation and vaporization of SiC.

Jacobson, Nathan S.; Lee, Kang N.; Maloy, Stuart A.; Heuer, Arthur H.

1993-01-01

400

Exposures to carbon dioxide in the poultry processing industry  

SciTech Connect

The use of dry ice has increased dramatically in poultry processing plants because of changes in the fast food industry. Concentrations of carbon dioxide in four such plants were measured and were found to exceed the Immediately Dangerous to Life and Health Level (50,000 ppm) inside holding coolers where ventilation is poor. In other areas, where dry ice is delivered to poultry packages, time-weighted average exposures can exceed the threshold limit value of 5000 ppm by substantial margins, even if local exhaust ventilation systems are present. Reports of adverse health effects from carbon dioxide exposure and various control measures are reviewed. Recommendations regarding sampling and analytical techniques also are presented. Operators of poultry plants where dry ice is used need to recognize the occupational hazards of exposure to carbon dioxide.

Jacobs, D.E.; Smith, M.S.

1988-12-01

401

Removal of phenols from water environment by activated carbon, bagasse ash and wood charcoal  

Microsoft Academic Search

Adsorption process is gaining interest as one of the effective processes of advanced wastewater treatment for treatment of industrial effluent containing toxic materials. The present work involves an investigation of the use of three carbonaceous materials, activated carbon (AC), bagasse ash (BA) and wood charcoal (WC), as adsorbents for removal of phenol from water. Batch experiments were carried out to

Somnath Mukherjee; Sunil Kumar; Amal K. Misra; Maohong Fan

2007-01-01

402

EVALUATION OF POWDERED ACTIVATED CARBON FOR REMOVAL OF TRACE ORGANICS AT NEW ORLEANS, LOUISIANA  

EPA Science Inventory

This research effort studied the effect of powdered activated carbon on the removal of trace organics in the water treatment process at New Orleans, LA. The water treatment processes were modeled in bench scale reactors that allowed control of treatment variables. A series of exp...

403

Removal of organic dyes using Cr-containing activated carbon prepared from leather waste.  

PubMed

In this work, hydrogen peroxide decomposition and oxidation of organics in aqueous medium were studied in the presence of activated carbon prepared from wet blue leather waste. The wet blue leather waste, after controlled pyrolysis under CO(2) flow, was transformed into chromium-containing activated carbons. The carbon with Cr showed high microporous surface area (up to 889 m(2)g(-1)). Moreover, the obtained carbon was impregnated with nanoparticles of chromium oxide from the wet blue leather. The chromium oxide was nanodispersed on the activated carbon, and the particle size increased with the activation time. It is proposed that these chromium species on the carbon can activate H(2)O(2) to generate HO radicals, which can lead to two competitive reactions, i.e. the hydrogen peroxide decomposition or the oxidation of organics in water. In fact, in this work we observed that activated carbon obtained from leather waste presented high removal of methylene blue dye combining the adsorption and oxidation processes. PMID:21752544

Oliveira, Luiz C A; Coura, Camila Van Zanten; Guimarães, Iara R; Gonçalves, Maraisa

2011-09-15

404

Mechanism of phenol adsorption onto electro-activated carbon granules.  

PubMed

The main purpose of this paper is to determine the mechanisms which govern the adsorption of the phenol onto electro-activated carbon granules. This new activation technique allowed an increase of the performance of the adsorbent. Two models were utilised to understand the improvement in the performance of electroactivated carbon granules. The first, a simple external resistance model based on film resistance, gave acceptable predictions, with an error of less than 15%, between the theoretical results and experimental data independent of the activation potential and phenol initial concentration. The second linear model, based on diffusion phenomena, was more representative in describing the experiment than the first model. It was observed that the electro-activation method did not change the mechanism which governs phenol adsorption onto granular carbon. Indeed, the same mathematical model based on diffusion phenomena made it possible to predict with a very low error (less than 5%) the experimental data obtained for the favourable activation potential, without activation potential and with an unfavourable activation potential. The electro-activation technique makes it possible to increase the number of active sites that improve the performance of the electro-activated granular carbon compared with conventional granular activated carbon. PMID:14630120

Lounici, H; Aioueche, F; Belhocine, D; Drouiche, M; Pauss, A; Mameri, N

2004-01-01

405

Critical condensed mass for activation of black carbon as cloud condensation nuclei in Tokyo  

Microsoft Academic Search

In the global modeling of black carbon (BC) particles, BC is categorized into hydrophobic (cloud condensation nuclei (CCN)-inactive) and hydrophilic (CCN-active) groups to represent wet removal process. However, the criteria separating these two types of BC have not been quantified. We investigate the dependence of CCN activity of atmospheric BC particles on the mass of condensed compounds (?m) in Tokyo

Mikinori Kuwata; Yutaka Kondo; Nobuyuki Takegawa

2009-01-01

406

Noncovalent functionalization of carbon nanotubes with redox active lignin derivatives  

Microsoft Academic Search

Kraft lignin (KL) was adsorbed on multi-wall carbon nanotubes (MWCNTs). After dispersing in dimethylsulfoxide the biopolymer coated MWCNTs formed stable suspensions that could be used to form cast films on glassy carbon electrodes. The composite films after initial oxidation showed redox functions characteristic of quinone moieties. These could be further reacted with thionine (TH) to form a redox active composite

Grzegorz Milczarek

2009-01-01

407

DESIGN AND CONSTRUCTION OF A MOBILE ACTIVATED CARBON REGENERATOR SYSTEM  

EPA Science Inventory

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

408

Hybrid Processing Techniques for Active Sonar.  

National Technical Information Service (NTIS)

Hybrid signal processing techniques, which combine both coherent and noncoherent operations, have been under development for active sonar applications for several years by the General Electric Company. The hybrid approach to sonar signal processing offers...

1970-01-01

409

40 CFR 60.1820 - How do I monitor the injection rate of activated carbon?  

Code of Federal Regulations, 2010 CFR

...monitor the injection rate of activated carbon?] 40 PROTECTION OF ENVIRONMENT...monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control...

2009-07-01

410

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

Code of Federal Regulations, 2010 CFR

...monitor the injection rate of activated carbon?] 40 PROTECTION OF ENVIRONMENT...monitor the injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control...

2009-07-01

411

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

Code of Federal Regulations, 2013 CFR

...injection rate of activated carbon? 62.15275 Section 62...Before August 30, 1999 Other Monitoring Requirements § 62.15275...injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control...

2013-07-01

412

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

Code of Federal Regulations, 2013 CFR

...injection rate of activated carbon? 60.1330 Section 60...After June 6, 2001 Other Monitoring Requirements § 60.1330...injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control...

2013-07-01

413

40 CFR 60.1820 - How do I monitor the injection rate of activated carbon?  

Code of Federal Regulations, 2013 CFR

...injection rate of activated carbon? 60.1820 Section 60...1999 Model Rule-Other Monitoring Requirements § 60.1820...injection rate of activated carbon? If your municipal waste combustion unit uses activated carbon to control...

2013-07-01

414

Use of Unburned Carbon in Fly Ash as Precursor for the Development of Activated Carbons  

Microsoft Academic Search

The increasing role of coal as a source of energy in the 21st century will demand environmental and cost-effective strategies for the use of carbonaceous waste products from coal combustion. The carbonaceous residue in fly ash, unburned carbon (UC), is a potential precursor for the production of adsorbent carbons, since it has gone through a devolatilization process while in the

M. Mercedes Maroto-Valer; Darrell N. Taulbee; Harold H. Schobert; James C. Hower; John M. Andrésen

415

Modeling of chemical vapor infiltration process for fabrication of carbon–carbon composites by finite difference methods  

Microsoft Academic Search

A finite difference (FD)-based method is proposed to describe the chemical vapor infiltration (CVI) processes for fabrication of carbon–carbon composites. The continuous, unsteady-state CVI processing can be divided into many discrete steady-state depositions by this model. Long cylindroid unidirectional carbon–carbon composites are prepared using the isothermal CVI technique to verify the accuracy of the FD methods. Experimental research shows that

Xianghui Hou; Hejun Li; Yixi Chen; Kezhi Li

1999-01-01

416

Processing and characterization of multi-scale hybrid composites reinforced with nanoscale carbon reinforcements and carbon fibers  

Microsoft Academic Search

Composites with multi-scale reinforcements consisting of multi-walled carbon nanotubes (MWCNTs) or carbon nanofibers (CNFs), along with micron-sized advanced carbon fibers, were processed using electrophoretic deposition (EPD) technique. Both anodic and cathodic electrophoretic deposition processes have been utilized for the deposition of nanoscale reinforcements on carbon fibers. Through hybridization of the reinforcement scales, we have demonstrated significantly improved electrical conductivity and

Sang-Bok Lee; Oyoung Choi; Wonoh Lee; Jin-Woo Yi; Byung-Sun Kim; Joon-Hyung Byun; Myung-Keun Yoon; Hao Fong; Erik T. Thostenson; Tsu-Wei Chou

2011-01-01

417

Hydrogen storage on activated carbon. Final report  

SciTech Connect

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

Schwarz, J.A. [Syracuse Univ., NY (United States). Dept. of Chemical Engineering and Materials Science

1994-11-01

418

Supporting the Active Learning Process  

ERIC Educational Resources Information Center

Many e-learning materials lack pedagogical principles and theoretical foundations. The great potential of activating learners and thus enriching learning experience is often unused in instructional software and online courses. Pedagogical theories like constructivist and action-orientated approaches should rather underlie the creation of new…

Schroeder, Ulrik; Spannagel, Christian

2006-01-01

419

MODELING TOC (TOTAL ORGANIC CARBON) REMOVAL BY GAC (GRANULAR ACTIVATED CARBON): THE GENERAL LOGISTIC FUNCTION  

EPA Science Inventory

Various models have been proposed to predict the performance of granular activated carbon (GAC) for single and bisolute systems, including the use of a bed depth service model for interpreting data for operation of adsorption beds to remove total organic carbon (TOC). This model ...

420

Synthesis of a high-yield activated carbon by air gasification of macadamia nut shell charcoal  

SciTech Connect

Macadamia nut shell charcoal was heated in an inert environment to temperatures above 1000 K (carbonized), reacted with oxygen (Po{sub 2} = 2.68--11.3 kPa) at temperatures between 525 and 586 K (oxygenated), and heated again in an inert environment to temperatures above 1000 K (activated) to produce an activated carbon. Carbons produced by this process possess surface areas and iodine numbers in the range of 400--550. Overall yields of these carbons (based on the dry, raw macadamia nut shell feed) ranged from 24 to 30 wt %. Under the conditions employed in this work, the rates of chemisorption and gasification were not mass transfer limited. Initially, the gasification reaction was first-order with respect to oxygen concentration but became independent of oxygen concentration as the surface sites of the carbon became saturated with oxygen.

Dai, X.; Antal, M.J. Jr. [Univ. of Hawaii at Manoa, Honolulu, HI (United States)] [Univ. of Hawaii at Manoa, Honolulu, HI (United States)

1999-09-01

421

Carbon Nanotube Activities at NASA-Johnson Space Center  

NASA Technical Reports Server (NTRS)

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

Arepalli, Sivaram

2006-01-01

422

Selection and preparation of activated carbon for fuel gas storage  

DOEpatents

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

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

1990-10-02

423

Natural gas storage with activated carbon from a bituminous coal  

USGS Publications Warehouse

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

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

1996-01-01

424

Quality of poultry litter-derived granular activated carbon.  

PubMed

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

Qiu, Guannan; Guo, Mingxin

2010-01-01

425

Removal efficiencies of endocrine disrupting chemicals by coagulation\\/flocculation, ozonation, powdered\\/granular activated carbon adsorption, and chlorination  

Microsoft Academic Search

Removal efficiencies of endocrine disrupting chemicals (EDCs), bisphenol A and nonylphenol, during various types of water\\u000a treatment processes were evaluated extensively using laboratory- and pilot-scale experiments. The specific processes of interest\\u000a were coagulation\\/flocculation sedimentation\\/filtration (conventional water treatment process), powdered activated carbon (PAC),\\u000a granular activated carbon (GAC), ozonation and chlorination. Batch sorption tests, coagulation tests, and ozone oxidation\\u000a tests were also

Keun Joo Choi; Sang Goo Kim; Chang Won Kim; Jae Kwang Park

2006-01-01

426

Growth and Persistence of Pathogens on Granular Activated Carbon Filters.  

National Technical Information Service (NTIS)

Three enteric pathogens Yersinia enterocolitica 0:8, Salmonella typhimurium, and enterotoxigenic Escherichia coli, were examined for their ability to colonize granular activated carbon (GAC) in pure cultures and in the presence of autochthonous river wate...

A. K. Camper M. W. LeChevallier S. C. Broadaway G. A. McFeters

1985-01-01

427

Activated Carbon Treatment of Industrial Wastewaters: Selected Technical Papers.  

National Technical Information Service (NTIS)

Because of the tremendous interest in the organic constituent removal by activated carbon, the two industrial categories displaying the most interest are the petroleum refining and petrochemical industries. EPA's Office of Research and Development has co-...

1979-01-01

428

Microbiology of Granular Activated Carbon Home Treatment Devices.  

National Technical Information Service (NTIS)

Consumer usage of point-of-use granular activated carbon filtration devices is increasing rapidly, yet there is little information available to the consumer concerning the efficacy of these devices. In particular, the consumer is very likely to be unaware...

D. J. Reasoner J. C. Blannon E. E. Geldreich

1986-01-01

429

GROWTH AND PERSISTENCE OF PATHOGENS ON GRANULAR ACTIVATED CARBON FILTERS  

EPA Science Inventory

Three enteric pathogens Yersinia enterocolitica 0:8, Salmonella typhimurium, and enterotoxigenic Escherichia coli, were examined for their ability to colonize granular activated carbon (GAC) in pure cultures and in the presence of autochthonous river water organisms. All three or...

430

Allowable Exposure Limits for Carbon Dioxide during Extravehicular Activity.  

National Technical Information Service (NTIS)

The intent was to review the research pertaining to human exposure to carbon dioxide (CO2) and to recommend allowable exposure limits for extravehicular activity (EVA). Respiratory, renal, and gastrointestinal systems may be adversely affected by chronic ...

A. J. Seter

1993-01-01

431

GRANULAR ACTIVATED CARBON ADSORPTION AND INFRARED REACTIVATION: A CASE STUDY  

EPA Science Inventory

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

432

Evaluation of Biological Activated Carbon for Industrial Water Reuse.  

National Technical Information Service (NTIS)

The Biological Activated Carbon (BAC) technology was tested for the production of reusable water, low in organics concentration, from industrial wastewater. Effluent streams from an oil refinery, a pulp mill, a textile dyeing mill, and a fungicide plant w...

M. Schwartz R. G. Rice A. Benedek

1982-01-01

433

Regeneration of Granular Activated Carbon Using Hydrothermal Technology.  

National Technical Information Service (NTIS)

The economic feasibility of using granular activated carbon (GAC) to remove organic contaminants from industrial and municipal wastewater is contingent upon its reuse during multiple adsorption-regeneration cycles (Van Vliet, 1991). The most common proces...

M. D. Sufnarski

1999-01-01

434

Activated Carbon Fiber Cloth Electrothermal Swing Adsorption System.  

National Technical Information Service (NTIS)

Capture and recovery of hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) from gas streams using physical adsorption onto activated carbon fiber cloth (ACFC) is demonstrated on the bench-scale. This system is regenerated electrothermal...

P. D. Sullivan M. J. Rood G. Grevillot J. D. Wander K. J. Hay

2004-01-01

435

Kinetics of Adsorption from Liquid Phase on Activated Carbon.  

National Technical Information Service (NTIS)

The kinetics of adsorption in activated carbon are investigated and single solute kinetic parameters are used to describe (predict) multisolute kinetics. This is achieved by studying the overall rate of adsorption of several organic compounds from dilute ...

M. S. Kouyoumdjiev

1992-01-01

436

Electrothermal Desorption of CWA Simulants From Activated Carbon Cloth.  

National Technical Information Service (NTIS)

The use of activated carbon fabrics (ACEs) that are desorbed electrothermally, also known as the Joule effect, is explored as a potential method to create a regenerating chemical warfare agent (CWA) filter. Electrical resistance vs. temperature measuremen...

P. D. Sullivan J. D. Wander K. C. Newsome

2004-01-01

437

PREDICTING PREFERENTIAL ADSORPTION OF ORGANICS BY ACTIVATED CARBON  

EPA Science Inventory

Preferential adsorption of organic compounds onto activated carbon from dilute aqueous solutions was studied to develop a comprehensive theoretical basis for predicting adsorption of multicomponent solutes. The research program investigates why some solutes are strong adsorbers, ...

438

Influence of the precursor metamorphism degree on preparation of nitrogen-enriched activated carbons by ammoxidation and chemical activation of coals  

SciTech Connect

The paper presents results of a study on obtaining N-enriched active carbons from four hard coals with different degree of metamorphism. The starting materials were carbonized, activated with KOH, and ammoxidized by a mixture of ammonia and air at the ratio 1:3 at 300 and 350{sup o}C, at each stage of the active carbon production. The efficiency of ammoxidation was found to depend on the degree of metamorphism of the precursor, the stage of processing at which ammoxidation is performed, and the temperature of this process. Ammoxidation of the active carbon led to a decrease in their surface area and pore volume, whereas that performed both at the stage of the precursor and the carbonizate brought improvement of textural parameters of the active carbons obtained. The sequence of the carbonization, activation, and ammoxidation processes had a significant effect on the acid-base character of the active carbon samples obtained. The majority of the active carbons modified at the stage of precursor and carbonizate showed considerable prevalence of surface acidic groups, whereas the samples ammoxidized after activation showed an intermediate acidic-basic character of the surface. 25 refs., 4 figs., 9 tabs.

Piotr Nowicki; Robert Pietrzak; Helena Wachowska [Adam Mickiewicz University, Pozna (Poland). Laboratory of Coal Chemistry and Technology

2009-04-15

439

Application of thermal analysis techniques in activated carbon production  

USGS Publications Warehouse

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

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

1996-01-01

440

Sorption of acid dyes from effluents using activated carbon  

Microsoft Academic Search

The sorption of three acid dyes, namely, Acid Red 114, Polar Yellow and Polar Blue RAWL, onto activated carbon, has been studied. Equilibrium isotherms have been measured for three single component systems (AB, AR, AY) and one binary component system (AB+AY). The isotherms were determined by shaking 0.05 g activated carbon, particle size range 500–710 ?m, with 0.05 dm3 dye

Keith K. H. Choy; Gordon McKay; John F. Porter

1999-01-01

441

Porosity in granular carbons activated with phosphoric acid  

Microsoft Academic Search

Three series of activated carbon have been prepared by heat treatment of peach stones impregnated with solutions of phosphoric acid, in order to analyze the effect of phosphoric acid on the yield, bulk density and porosity of the resultant activated carbons. The analysis of the adsorption isotherms of N2 at 77 K. CO2 at 273 K and n-C4H10, at 273

M. Molina-Sabio; F. RodRíguez-Reinoso; F. Caturla; M. J. Sellés

1995-01-01

442

A sustainable route for the preparation of activated carbon and silica from rice husk ash.  

PubMed

An environmentally friendly and economically effective process to produce silica and activated carbon form rice husk ask simultaneously has been developed in this study. An extraction yield of silica of 72-98% was obtained and the particle size was 40-50 nm. The microstructures of the as-obtained silica powders were characterized by X-ray diffraction (XRD) and infrared spectra (IR). The surface area, iodine number and capacitance value of activated carbon could achieve 570 m(2)/g, 1708 mg/g, 180 F/g, respectively. In the whole synthetic procedure, the wastewater and the carbon dioxide were collected and reutilized. The recovery rate of sodium carbonate was achieved 92.25%. The process is inexpensive, sustainable, environmentally friendly and suitable for large-scale production. PMID:21194835

Liu, Yan; Guo, Yupeng; Zhu, Yanchao; An, Dongmin; Gao, Wei; Wang, Zhuo; Ma, Yuejia; Wang, Zichen

2011-02-28

443

Carbon Nanotube Materials for Substrate Enhanced Control of Catalytic Activity  

SciTech Connect

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

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

2007-05-01

444

Steric and electronic effects influencing ?-aryl elimination in the Pd-catalyzed carbon-carbon single bond activation of triarylmethanols.  

PubMed

An analysis of the palladium-catalyzed activation of carbon-carbon single bonds within triarylmethanols has led to a greater understanding of factors influencing the ?-aryl elimination process responsible for C-C bond cleavage. A series of competition reactions were utilized to determine that ?-aryl elimination of aryl substituents containing ortho-substitution proceeds with significant preference to unsubstituted phenyl rings. Further experiments indicate that substrates containing either strongly donating or withdrawing substituents are cleaved from triarylmethanols more readily than relatively neutral species. PMID:23346914

Bour, James R; Green, Jacob C; Winton, Valerie J; Johnson, Jeffrey B

2013-02-15

445

Development of porosity in carbons from yeast grains by activation with alkali metal carbonates.  

PubMed

Cellular structured activated carbon samples were prepared with the aid of alkali carbonates X2CO3 (X = Li, Na, K, Rb, or Cs) from dry bread yeast with a milling procedure. The resultant carbon possesses a very large adsorption amount even for supercritical methane. The activation with Cs2CO3 gave the greatest surface area of 2420 m2 g(-1) from the subtracting pore effect method. The activation efficiency of X2CO3 (X = Li, Na, K, Rb, and Cs) was associated with the order of Gibbs free energy of X2O (X = Li, Na, K, Rb, and Cs) which should play an important role in the gasification. The carbon activated with Rb2CO3 gave the greatest adsorption amount of supercritical methane of 90 mg g(-1) at 0.9 MPa at 303 K. PMID:18068716

Urabe, Y; Ishikura, T; Kaneko, K

2008-03-01

446

REMOVAL OF ORGANIC POLLUTANTS FROM SUBCRITICAL WATER WITH ACTIVATED CARBON  

SciTech Connect

The Energy & Environmental Research Center (EERC) has demonstrated that controlling the temperature (and to a lesser extent, the pressure) of water can dramatically change its ability to extract organics and inorganics from matrices ranging from soils and sediments to waste sludges and coal. The dielectric constant of water can be changed from about 80 (a very polar solvent) to <5 (similar to a nonpolar organic solvent) by controlling the temperature (from ambient to about 400 C) and pressure (from about 5 to 350 bar). The EERC has shown that hazardous organic pollutants such as pesticides, PACS (polycyclic aromatic hydrocarbons), and PCBs (polychlorinated biphenyls) can be completely removed from soils, sludges, and sediments at temperatures (250 C) and pressures (<50 atm) that are much milder than typically used for supercritical water processes (temperature >374 C, pressure >221 atm). In addition, the process has been demonstrated to be particularly effective for samples containing very high levels of contaminants (e.g., part per thousand). Current projects include demonstrating the subcritical water remediation process at the pilot scale using an 8-liter system constructed under separate funding during 1997. To date, subcritical water has been shown to be an effective extraction fluid for removing a variety of organic pollutants from soils and sludges contaminated with fossil fuel products and waste products, including PACS from soil (e.g., town gas sites), refining catalysts, and petroleum tank bottom sludges; PCBs from soil and sediments; toxic gasoline components (e.g., benzene) from soil and waste sludge; and phenols from petroleum refinery sludges. The obvious need to clean the wastewater from subcritical water processes led to preliminary experiments with activated carbon placed in line after the extractor. Initial experiments were performed before and after cooling the extractant water (e.g., with water at 200 C and with water cooled to 25 C). Surprisingly, the ability of activated carbon to remove organics from the water is better at a high temperature than at room temperature. These initial results are opposite to those expected from chromatographic theory, since the solubility of the organics is about 100,000-fold higher in the hot water than in ambient water. At present, the physicochemical mechanism accounting for these results is unknown; however, it is possible that the lower surface tension and lower viscosity of subcritical water (compared to water at ambient conditions) greatly increases the available area of the carbon by several orders of magnitude. Regardless of the mechanism involved, the optimal use of activated carbon to clean the wastewater generated from subcritical water remediation will depend on obtaining a better understanding of the controlling parameters. While these investigations focused on the cleanup of wastewater generated from subcritical water remediation, the results also apply to cleanup of any wastewater contaminated with nonpolar and moderately polar organics such as wastewaters from coal and petroleum processing.

Steven B. Hawthorne; Arnaud J. Lagadec

1999-08-01

447

Inner-tubular physicochemical processes of carbon nanotubes  

Microsoft Academic Search

Nanosized inner cavities of carbon nanotubes (CNTs) afford quasi-one-dimensional (1D) confined space, in which materials adsorbed\\u000a or filled are of reactivity greatly different from the materials adsorbed on a planar surface and quite a number of curious\\u000a physicochemical processes will possibly occur. In other words, 1D CNT nanochannels may serve as “nanosized test tubes”. In\\u000a this article, on the basis

Quanhong Yang; Lixiang Li; Huiming Cheng; Maozhang Wang; Jinbo Bai

2003-01-01

448

Processing and performance of nanophased braided carbon\\/epoxy composites  

Microsoft Academic Search

A systematic study has been carried out to investigate mechanical properties of 2D nanophased braided carbon\\/epoxy composites. SC-15 epoxy with three types of braided fabrics: ±45°, 0\\/±45°, and 0\\/±60° was used to fabricate composite laminates using vacuum assisted resin infusion molding (VARIM) process. Low-velocity impact (LVI), ultrasonic nondestructive evaluation (NDE) and 3-point bend flexure studies were carried out on biaxial

Mahesh V. Hosur; Shaik Jeelani

2010-01-01

449

Chemical Vapor Deposition of ?-SiC Nanowires on Granular Active Carbon Cylinders Loaded with Iron Nanoparticles Inside the Pores  

Microsoft Academic Search

A new method for chemical vapor deposition of ?-SiC nanowires on granular active carbon loaded with iron nanoparticles inside the pores is developed. In this process, mesoporous active carbon was used as both a carbon source material and a template to generate nanometer-diameter catalyst particles that define the size of wires produced by vapor-liquid-solid (VLS) growth. Transmission electron microscopy reveals

Meng Guo-wen; Zhang Li-de; Qin Yong; F Phillipp; Qiao Sheng-ru; Guo Hai-ming; Zhang Shu-yuan

1998-01-01

450

Computational Tools for Accelerating Carbon Capture Process Development  

SciTech Connect

The goals of the work reported are: to develop new computational tools and models to enable industry to more rapidly develop and deploy new advanced energy technologies; to demonstrate the capabilities of the CCSI Toolset on non-proprietary case studies; and to deploy the CCSI Toolset to industry. Challenges of simulating carbon capture (and other) processes include: dealing with multiple scales (particle, device, and whole process scales); integration across scales; verification, validation, and uncertainty; and decision support. The tools cover: risk analysis and decision making; validated, high-fidelity CFD; high-resolution filtered sub-models; process design and optimization tools; advanced process control and dynamics; process models; basic data sub-models; and cross-cutting integration tools.

Miller, David

2013-01-01

451

carbon cycle  

NSDL National Science Digital Library

Life on earth is based on carbon. Living things acquire carbon from their environment - from air, water, soil, and rock and from other living things - through processes such as photosynthesis, respiration and decomposition. The carbon cycle model is a representation of the movement of carbon from sources to sinks through chemical and physical transfers. The carbon cycle activity allows students to see the effect of fossil fuel burning on the carbon cycle.

School, Maryland V.

452

Production of granular activated carbons from loquat stones by chemical activation  

Microsoft Academic Search

This paper describes the production of activated carbons by chemical activation with KOH and NaOH of the chars obtained through carbonization of loquat stones at 600°C. The chars in the 1.0–2.0mm size range were activated at carbonization temperatures ranging from 600°C to 1000°C, heating rate of 10°C\\/min and a char\\/chemical agent mass ratio of 1\\/2 under nitrogen flow. In addition,

Hale Sütcü; Hakan Demiral

2009-01-01

453

Characteristics of activated carbons prepared from pistachio-nut shells by physical activation  

Microsoft Academic Search

Activated carbons were prepared from pistachio-nut shells, which are one type of lignocellulosic material, by a two-step physical method. The effects of the preparation variables on the activated carbon pore structure were studied, followed by the optimization of these operating parameters. It was found that the activation temperature and dwell time are the important parameters that affect the characteristics of

Ting Yang; Aik Chong Lua

2003-01-01

454

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

NASA Astrophysics Data System (ADS)

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.

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

2009-07-01

455

Activated Carbon from Peach Stones Using Phosphoric Acid Activation at Medium Temperatures  

Microsoft Academic Search

In the present study, the activation features of phosphoric acid have been investigated using waste peach stones as the raw material in the production of granular activated carbon. Thermogravimetry\\/differential thermal analysis was conducted to characterize the thermal behavior of peach stone and titration method was used to evaluate the adsorption capacity of the produced activated carbon. It was observed that

Dong-Su Kim

2004-01-01

456

Preparation of titanium dioxide\\/activated carbon composites using supercritical carbon dioxide  

Microsoft Academic Search

The penetration of titanium tetraisopropoxide (TTIP) dissolved in supercritical CO2 into the nano-spaces of an activated carbon was studied for the preparation of a TiO2-coated activated carbon. The conversion of TTIP to TiO2 through thermal decomposition was confirmed by evolved gas analysis during heat treatment under a N2 flow. Acetone was detected in the evolved gas, which suggested that some

Narihito Tatsuda; Hiroshi Itahara; Norihiko Setoyama; Yoshiaki Fukushima

2005-01-01

457

Pedogenetic processes and carbon budgets in soils of Queretaro, Mexico  

NASA Astrophysics Data System (ADS)

Pedogenetic processes have been investigated in two different physiographic regions of the state of Querétaro in order to assess the carbon budget of soils, looking into the gains and losses of organic and inorganic carbon: In the mountain region of the natural reserve Sierra Gorda (SG) with soils developed on cretaceous argillites and shales under sub-humid temperate to semi-arid conditions, and in the Transmexican Volcanic Belt (TMVB) with soils developed on acid and intermediate igneous rocks under humid temperate climate in the highlands and semi-arid and subhumid subtropical conditions in the lowlands. The analyses of soil organic carbon (SOC) and soil inorganic carbon (SIC) of the SG region, including additional physical, chemical and mineralogical investigations were based on 103 topsoils in an area of 170 km2. The analyses in the TMVB region were based on the profiles of a soil toposequence from high mountainous positions down to the plains of the lowlands. The results show a SOC accumulation from temperate to semi-arid forest environments, based on processes of humification and clay formation including the influence of exchangeable Ca and the quantity and quality of clay minerals. The turnover rates of SOC and SIC depended largely on the rock parent materials, especially the presence of carbonate rocks. Moreover, we found that the SOC content and distribution was clearly depending on land use, decreasing from forests to agricultural land, such as pasture and cropping areas and were lowest under mining sites. The highest SIC pools were found in accumulation horizons of soils under semi-arid conditions. On all investigated sites SOC decreased the mobility of cations and especially that of heavy metals, such as As, Hg, Sb, Pb, and Cd.

García Calderón, Norma Eugenia; Fuentes Romero, Elizabeth; Hernandez Silva, Gilberto

2014-05-01

458