Characterization of sorption of non-ionic organic compounds on carbon-based nanomaterials

点击翻译按钮获取中文摘要

The interaction between carbon nanomaterials (CNM) and organic or inorganic compounds is studied by many scientists, because of the strong sorption of CNM. Although already many studies have been conducted with different compounds and materials in batch experiments, a general understanding of the underlying sorption mechanisms was missing. The results of the first project phase helped to improve the knowledge in this field concerning carbon nanotubes. Different models were developed, which give information about the relevant sorption mechanisms, but they are only valid for certain environmental conditions (pH, ionic strength, temperature) and are not transferable to other conditions. The influence of environmental conditions on sorption was studied in literature only for a limited number of compounds and materials with the consequence that even here a general understanding of the underlying processes is still missing. The batch experiments used in literature and the first project phase had disadvantages, namely the long equilibration time and limited amount of sorbent and hence the variation in environmental conditions and material characteristics was limited. In the proposed follow-up project to the mechanistic investigations concerning sorption should be continued and the focus is shifted on the variability of sorption to different types of CNM and on the effect of different environmental conditions on sorption. For this purpose, a column-based method shall be developed, that is able to substitute the classical batch approach and thus to enable the faster variation of environmental conditions with less time-consuming work. First, it is investigated with validated columns how comparable results to batch experiments can be obtained. After establishment of this method, various sorbates are used as chemical probes to characterize the different sorbents. Sorption experiments will be performed at different environmental conditions to investigate the influence of these parameters on sorption. The results of these measurements are implemented in existing models or used to develop new models, which enable the prediction of sorption of organic compounds to CNM for different environmental conditions. Based on an improved process understanding, columns packed with CNM will be exemplary applied for separations in the field of analytical chemistry in comparison with a classical C18-phase.