James S. Mattson

Infrared Internal Reflectance Spectroscopic Determination of Surface Functional Groups on Carbon

An internal reflectance spectrophotometrie technique for the direct study of the infrared spectrum of surface functional groups on carbon is presented. The applicability and limitations of this technique are discussed. The spectra obtained for three different types of carbon; i.e., graphite, carbon black, and activated carbon, are presented. On the basis of interpretation of the spectra for these systems, it is suggested that the predominant surface functional groups on activated carbon are oxygen-containing earbonyl groups. The relative abundance of all oxygen-containing functional groups was found to be a function of both the type of carbon and its pretreatment.

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

Abstract The nature of the activated carbon surface with respect to surface functional groups has been examined using infrared internal reflectance spectroscopy (IRS). By employing this recently developed technique, the surface character of laboratory-activated sugar carbons has been examined as a function of activation temperature and atmosphere. The IRS spectra obtained for series of O 2 and CO 2 + O 2 activated carbons indicate the presence of dicarboxylic acids and quinone carbonyl groups. The adsorption isotherms of p -nitrophenol on these carbons has been studied and has been shown to conform with the previously suggested adsorption mechanism involving the formation of a donor-acceptor complex with surface carbonyl oxygen.

Investigation of Optically Dense Systems by Internal Reflection Spectroscopy: Experimental Considerations

Many materials of importance in natural waters and waste-water systems—e.g., sediments, suspensions, and precipitates—are optically opaque. The application of transmission spectroscopy for purposes of analysis and identification of such materials is therefore usually precluded. For cases in which conventional transmission spectroscopy is not feasible because of scattering effects and/or extensive attenuation of incident light, the technique of internal-reflectance spectroscopy (IRS) often provides a means for obtaining characteristic spectral data. Several specific examples are presented to indicate that IRS provides high contrast spectra comparable to the best transmission spectra for “clean” systems, provided appropriate IRS geometry, components, and techniques are selected. Examples include active carbons and carbon blacks, marine sediments, freshwater sediments, and extremely turbid suspensions. Experimental considerations involved in the application of IRS to such systems are discussed. Interpretation of IRS spectra, and the differences to be expected between IRS and transmission spectra are also considered.

Determination of 16O in Microcrystalline Carbon by Indirect Neutron Activation Analysis

A method for the determination of oxygen in carbon and organic materials, employing the 16O(3T,n)18F reaction, is described. The technique is applicable for amounts of 12O as low as 0.1 mg, and the application of the method to the determination of the oxygen content in activated carbon is reported.