Graphit als Modell-Adsorbens in wässrigen Lösungen
Adsorption processes from aqueous solutions for the removal of aromatic compounds by activated carbon are influenced by various adsorption mechanisms. In contrast to activated carbon, graphite is a homogeneous sp2-hybridized material, which is excellently suited for the investigation of adsorption mechanisms. In particular, functional oxygen groups on the graphite surface weaken the hydrophobic character of pristine graphite by using of special modification methods. Various modification methods such as ozonation for the production of graphite oxide were carried out experimentally and analytical methods were used to examine the modified material for changes in surface chemistry. By Adsorption batch tests the adsorption affinity of selected aromatic compounds were compared between pristine graphite and graphite oxide. Amongst other results, it was found that bicyclic aromatics better adsorb onto both, pristine and ozonised graphite surface than monocyclic aromatics. Further tests were carried out to investigate the concentration behaviour of the test substances and factors that could influence the adsorption process. More in-depth studies on this topic for more comprehensive results and improved method developments, for instance to modify the graphite surface properties, are required.