Comparison of three active carbons using LSER modeling: prediction of their selectivity towards pairs of volatile organic compounds (VOCs)

In order to classify chemically modified active carbons in terms of selectivity towards pairs of Volatile Organic Compounds (VOCs), and in order to follow their chemical treatment, two active lignites were characterized by the Linear Solvation Energy Relationship (LSER) equation of Abraham et al. Results are compared to those obtained with a commercial active carbon used as a reference material. Three LSER equations were determined by using gas-solid partition coefficients at infinite dilution of 13 probe molecules in gas chromatographic method of elution by characteristic point. In this way, the three active carbons were characterized in term of molecular interaction parameters. Their significance is discussed and is in good agreement with known chemical composition data. The study shows that the commercial material is the most selective adsorbent for the test-pair (methylethylketone/dichloroethane) and that both activated lignites are selective for the other test-pair of VOCs. Then, the limits of the predictions of selectivity towards the test-pair of VOCs (methanol/dichloromethane) are also discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.