Surface oxides of activated carbon: Internal reflectance spectroscopic examination of activated sugar carbons

Mattson, James S.; Lee, Lyon; Mark, Harry B.; Weber, Walter J.

doi:10.1016/0021-9797(70)90031-7

Cited by 46 publications

(10 citation statements)

References 21 publications

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“…This could possibly account for the apparent importance of the basic surface site, especially at basic pH values where the phenolate anions predominate. Mattson et at. (1970) substantiate the presence of significant numbers of carbonyl and carboxyl functional groups on the surfaces of activated carbon using infrared internal reflectance spectrophotometric techniques.…”

Section: Resultsmentioning

confidence: 99%

Equilibrium adsorption of chlorophenols on granular activated carbon

Nelson¹,

Yang²

1995

Water Environment Research

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The adsorption of chlorinated phenols from aqueous solution on granular activated carbon was studied in batch reactors. Singlecomponent equilibrium adsorption data for the eight compounds in two concentration ranges at pH 7.0 and 30°C were fit well by both the Langmuir and the Freundlich equations. The adsorptive capacities at pH 7.0 increase from pentachlorophenol to trichlorophenols and are fairly constant from trichlorophenols to monochlorophenols. 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 has been proposed to describe the effect of pH on adsorption equilibria of chlorophenols on activated carbon. Activated carbon surface functional sites are divided into acidic and basic groups with which molecular and ionized forms of chlorophenols interact, respectively, and form two neutral complexes. The simulations of the model are in excellent agreement with the experimental data. Waler Environ. Res., 67, 892 (1995).

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Section: Resultsmentioning

confidence: 99%

Equilibrium adsorption of chlorophenols on granular activated carbon

Nelson¹,

Yang²

1995

Water Environment Research

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“…Low temperature air oxidation ("aging") yields surface groups that can neutralize acids (H carbons). These groups decompose generally at high temperatures (above 600°C) under formation of mainly CO and are probably of the chinon-type bonding (37). The surface coverage is limited to approx.…”

Section: Admentioning

confidence: 99%

Fundamentals and Practical Implications of Activated Carbon Production by Partial Gasification of Carbonaceous Materials

Wigmans

1986

Carbon and Coal Gasification

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“…Other studies by these authors demonstrated that the complexes desorbed as CO do not affect adsorption of phenols, while the more acidic complexes desorbed as CO 2 hindered phenolic adsorption. Furthermore, Mattson et al ( , ) found the adsorption of p -nitrophenol to be enhanced by the presence of carbonyl groups, which is believed to form electron donor−acceptor complexes with the aromatic ring of the nitrophenol.…”

Section: Introductionmentioning

confidence: 99%

Impact of Oxygen-Containing Surface Functional Groups on Activated Carbon Adsorption of Phenols

Tessmer

Vidic

Uranowski

1997

Environ. Sci. Technol.

212

129

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The adsorptive capacity of activated carbons for phenolic compounds increases significantly in the presence of dissolved oxygen (oxic conditions) due to the oligomerization of these compounds through oxidative coupling reactions. With increased capacity comes an increase in the amount of irreversible adsorption, which is defined as adsorbate that cannot be recovered by solvent extraction. The objective of this study was to determine the impact of oxygen-containing functional groups on activated carbon surface on the irreversible adsorption of phenolic compounds in the presence of dissolved oxygen. The adsorptive capacities and surface functional group (SFG) content were evaluated for seven commercially available activated carbons and an activated carbon whose SFG content was modified by outgassing. This study demonstrated that the presence of acidic surface functional groups hinders the ability of activated carbon to adsorb phenolic compounds under oxic conditions by reducing its effectiveness in promoting adsorption via oxidative coupling reactions. The catalytic ability of activated carbon may be enhanced by eliminating the acidic functional groups and encouraging formation of basic groups by outgassing at 900 °C. Re-introduction of oxygen-containing acidic surface functional groups onto the surface of outgassed GAC negates any gains in catalytic ability produced by the outgassing procedure. Therefore, outgassing affects the adsorption of phenolic compounds only by changing the amount and composition of oxygen complexes. Outgassing at higher temperatures (e.g., 1200 °C) causes the elimination of oxygen complexes, resulting in a more basic carbon that does not contain oxygenated basic groups. Greater structural ordering and delocalized electrons on the carbon surface may increase the basicity of the carbon but do not enhance its ability to promote ir reversible adsorption. The presence of oxygen-containing basic groups (e.g., chromene-type, pyrone-type) is likely a key factor in promoting irreversible adsorption.

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Surface oxides of activated carbon: Internal reflectance spectroscopic examination of activated sugar carbons

Cited by 46 publications

References 21 publications

Equilibrium adsorption of chlorophenols on granular activated carbon

Equilibrium adsorption of chlorophenols on granular activated carbon

Fundamentals and Practical Implications of Activated Carbon Production by Partial Gasification of Carbonaceous Materials

Impact of Oxygen-Containing Surface Functional Groups on Activated Carbon Adsorption of Phenols

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