Sorption and Desorption Processes
of Organic Contaminants
on Carbonaceous Materials.
Technische Universität, Darmstadt
[Ph.D. Thesis], (2012)
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|Item Type:||Ph.D. Thesis|
|Title:||Sorption and Desorption Processes of Organic Contaminants on Carbonaceous Materials|
Sorption is considered the most important abiotic process for determining the fate and transport of organic contaminants in the environment. Hence, we investigated whether sorption is fully reversible or whether a irreversibly sorbed pollutant fraction remains in the sorbent and if the total amount of contaminants is available to biological receptors or only a fraction of them. This process has a great importance for remediation targets. This question was examined in multi-stage batch sorption and desorption experiments with Trichloroethylene (TCE) and Tetrachloroethylene (also perchloroethylene PCE), as well as o-xylene and p-xylene, in combination with the sorbents activated carbon, charcoal, peat, and the hydrophobic zeolite Y-200. It was shown that the structural composition of the sorbent is one of the important features for a contaminant adsorption-resistant fraction. Hence, the rigid pore system of micro porous zeolite Y-200 exhibits the mostly reversible sorption. Charcoal and activated carbon showed a significantly irreversible sorption, or at least a very slowly desorbing pollutant fraction. This fraction can be harmful in environment due to different kinds of pollutants. Competitive sorption may cause releasing of this fraction.
Generally, the results indicate that the sorption in the above mentioned sorbents for the different chemicals investigated is dominated by pore filling processes, except for peat. A nonlinear type sorption isotherm is described by the combination of the partitioning and pore-filling mechanisms.
|Place of Publication:||Darmstadt|
|Classification DDC:||500 Naturwissenschaften und Mathematik > 540 Chemie|
|Divisions:||11 Department of Materials and Earth Sciences|
|Date Deposited:||15 Oct 2012 15:01|
|Last Modified:||07 Dec 2012 12:05|
|Referees:||Ensinger, Prof Wolfgang and Schüth, Prof Christoph|
|Refereed:||21 September 2012|