Modeling competitive adsorption of chlorinated volatile organic compounds with the Dubinin-Radushkevich equation

A recent paper showed that the breakthrough curves of volatile organic comp ound (VOC) mixtures on zeolite replaced the adsorbates in order of decreasi ng boiling points (PCE > TCE > DCA > DCM) and could be predicted by the boi ling point of the compounds (similar to distillation). A previous study by the authors found a similar result on granulated activated carbon (PCE > TC E > CTC > TCA > t-12DCE > CHL > DCE), but used another thermodynamic proper ty, the heat of vaporization to predict the breakthrough order. The authors had used the heat of vaporization in a model, based on the Dubinin-Radushk evich equation, to predict the adsorption of several VOCs onto granulated a ctivated carbon with isotherm data of only one compound. This paper shows that the use of either the heat of vaporization or the boi ling point are interchangeable. Both predicted the breakthrough curves of a mixture of adsorbates from granulated activated carbon and either can be u sed for a competitive adsorption model employing the Dubinin-Radushkevich e quation. (C) 2001 Elsevier Science BN. All rights reserved.