Microstructure, dangling bonds and impurities in activated carbons

Manivannan, A.; Chirila, M. M.; Giles, N. C.; Seehra, M. S.

doi:10.1016/s0008-6223(99)00052-4

Cited by 95 publications

(48 citation statements)

References 24 publications

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“…N 2 -AC produced values of N s = 3.04 × 10 16 g -1 and g = 2.0020. Three activated carbons with surface areas of 1000-2000 m 2 /g were previously reported to have ESR activities of N s = 1.8 × 10 16 -8.9 × 10 17 g -1 and g = 2.0028 (Manivannan et al, 1999). N 2 -AC with a surface area of 1530 m 2 /g was considered to produce reasonable values of N s and g. Because the g value of N 2 -AC was quite close to that of free electrons (2.0023), the unpaired electron was almost unyoked.…”

Section: Surface Area Free Radical and Functional Groups Of Macromomentioning

confidence: 99%

“…Native carbon in heterogeneous fly ash is believed to possess a more complex system. The large structure of macromolecular carbon is characterized by various indicators such as surface area, free radical, and functional groups (Hontoria-Lucas et al, 1995;Manivannan et al, 1999;Adib et al, 2000;Takaoka et al, 2007). These properties of the large structure of macromolecular carbon can be altered following the application of various chemical solutions including nitric acid (HNO 3 ), hydrogen peroxide (H 2 O 2 ), sulfuric acid (H 2 SO 4 ), and urea (Otake and Jenkins, 1993;Gomez-Serrano et al, 1994;Gomez-Serrano et al, 1997;Adib et al, 2000;Takaoka et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Influence of the Properties of Macromolecular Carbon on de Novo Synthesis of PCDDs, PCDFs, PCBs, and Chlorobenzenes

Fujimori

Nishimura

Oshita

et al. 2014

Aerosol Air Qual. Res.

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We examined the influence of the properties of macromolecular carbon on thermochemical de novo synthesis of toxic chlorinated aromatic compounds (aromatic-Cls), such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), biphenyls (PCBs), and chlorobenzenes (CBzs). Six types of macromolecular carbons were prepared. Some activated carbon samples were modified by chemical solvents, such as nitric acid, hydrogen peroxide, sulfuric acid, and urea solutions, to change the properties of the activated carbon. We characterized six macromolecular carbons by surface area (8.8-1540 m 2 /g), free radicals (N s = not analyzed to 67.0 × 10 19 g -1 , g = 2.0011-2.0098), and functional groups (O-H, C-H, C=O, C=C, C-O, and C-OH). Concentrations of aromatic-Cls at 300-400°C, such as PCDDs, PCDFs, PCBs, and CBzs, were clearly influenced by the type of macromolecular carbon. Their distribution between the ash/gas phases implied that increasing the surface area mainly enhanced the adsorption capacity of macromolecular carbon, while increasing the number of free radicals mainly enhance the reaction activity of macromolecular carbon. The PCDD/PCDF ratio suggested that various modifications of macromolecular carbon contributed to the generation of PCDDs in addition to the catalytic behavior of copper. Under most conditions, the surface area of macromolecular carbon did not have a strong correlation with the generation of PCDDs, PCBs, and CBzs, but it did show have a correlation with the generation of PCDFs. One of the destructive effects of aromatic-Cls resulted from the free radicals in macromolecular carbon. The C=O bond (ca. 1720 cm -1 ) functional group in macromolecular carbon had no strong correlation with the generation of aromatic-Cls, because free radicals had a destructive effect. The functionalities of ether (C-O) or phenolic OH (C-OH) in macromolecular carbon were causative factors in the generation of oxygen-containing aromatic-Cls, such as PCDDs and PCDFs.

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Section: Surface Area Free Radical and Functional Groups Of Macromomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of the Properties of Macromolecular Carbon on de Novo Synthesis of PCDDs, PCDFs, PCBs, and Chlorobenzenes

Fujimori

Nishimura

Oshita

et al. 2014

Aerosol Air Qual. Res.

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“…13 and summarized in Table 8 are: 1. the g factor values of the original char, char treated with base and acid as well as the char activated with K 2 CO 3 are close to the g value of the free electron (2.002312) with in the error of our experiments (±0.002). Manivannan et al [37], Vilas Ganpat Pol et al [25], Singer and Wagoner [38], Chauvert et al [39], Zhuo et al [40] have made similar observations in the case of carbon materials produced from a variety of precursors. 2. the peak to peak separation was found to be higher in the case of the original char (DH = 11.0 Gauss) compared to either the char treated with base and acid or the char activated with K 2 CO 3 .…”

Section: Effect Of K 2 Co 3 Activation On the Chemical Environment Anmentioning

confidence: 73%

Development of Carbon Materials for Energy and Environmental Applications

2009

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Methodologies for generating carbon materials from unusual natural sources like Limonea acidissima and Calotropis gigantea are reported. The carbon materials thus obtained have been characterized using a variety of tools. The possibility of modulating the textural properties of these materials has been examined. The carbon materials synthesized have been exploited for specific applications, such as support for noble metals for use in Direct Methanol Fuel Cells and as support for heteropoly acid for the production of gasoline additive. In addition, the utility of some of the activated carbon materials (from commercial sources) for the removal of sulphur from crude petroleum sources is also examined.

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“…The average size of coherently scattering domains along the normal to graphite layers L c , was determined from the full width at half-maximum of the reflection 002, after correcting for the instrumental broadening (β 002 ) by the Scherrer equation [14]. The interlayer spacing d 002 was determined by using the Bragg law [12].…”

Section: Characterizationmentioning

confidence: 99%

Low temperature one-step synthesis of cobalt nanowires encapsulated in carbon

Majewska

Michalkiewicz

2013

Appl. Phys. A

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The one-step method of carbon nanotubes filled with continuous cobalt nanowires (CoF-CNT) synthesis is presented. Co/ZSM-5 (8 wt% Co) was used as catalyst for CoF-CNT production by methane decomposition at the temperature of 400°C and 800°C at atmospheric pressure in a conventional gas-flow system. The average diameter of the CoF-CNT is about 25 and 40 nm for products obtained at 400°C and at 800°C, respectively. The average size of coherently scattering domains along the normal to graphite layers L c , the interlayer spacing d 002 , the graphitization degree of carbon, and the relative intensities of the G and D bands in Raman spectroscopy were determined to characterize the quality of carbon. It was proved that cobalt-filled carbon nanotubes can be produced by a simple method. The results of XRD, FE-SEM, and TEM show that CoF-CNT can be obtained even at 400°C by catalytic decomposition of methane. On the basis of XRD, TEM, Raman spectroscopy was found that at a temperature of 800°C, a better quality of carbon was produced.

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Microstructure, dangling bonds and impurities in activated carbons

Cited by 95 publications

References 24 publications

Influence of the Properties of Macromolecular Carbon on de Novo Synthesis of PCDDs, PCDFs, PCBs, and Chlorobenzenes

Influence of the Properties of Macromolecular Carbon on de Novo Synthesis of PCDDs, PCDFs, PCBs, and Chlorobenzenes

Development of Carbon Materials for Energy and Environmental Applications

Low temperature one-step synthesis of cobalt nanowires encapsulated in carbon

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