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Surface Characterization of Activated Charcoal by X-Ray Photoelectron Spectroscopy (XPS): Correlation with Phenobarbital Adsorption Data

Authors :
Burke, Gerald M.
Wurster, Dale Eric
Berg, Mary J.
Veng-Pedersen, Peter
Schottelius, Dorothy D.
Source :
Pharmaceutical Research; January 1992, Vol. 9 Issue: 1 p126-130, 5p
Publication Year :
1992

Abstract

X-ray photoelectron spectroscopy (XPS) was used to identify the functional states of carbon existing on the surfaces of various activated charcoals. The relative percentages of carbon, oxygen, and detectable trace elements comprising the activated charcoal surfaces were determined. Analysis of the carbon core-electron binding energy region revealed the existence of one hydrocarbon state (C–H, C–C are indistinguishable) and three oxygen-containing functional states. These states were hydroxyls or ethers (C–O), carbon-yls (C = O), and carboxylic acids or esters (O–C = O). The C–O functional state contributed approximately 60–70% to the total percentage of oxygen-containing states. A very good correlation existed between the apparent areas occupied on the adsorbent surface per phenobarbital molecule and the relative percentages of the C–O functional state. Previously reported heat of displacement results for phenobarbital adsorption are now explained since the C–O state appears to be the primary site involved in the binding of phenobarbital by the activated charcoals.

Details

Language :
English
ISSN :
07248741 and 1573904X
Volume :
9
Issue :
1
Database :
Supplemental Index
Journal :
Pharmaceutical Research
Publication Type :
Periodical
Accession number :
ejs15446913
Full Text :
https://doi.org/10.1023/A:1018900431661