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

由于碳纳米材料具有很强的吸附性，其与有机或无机化合物之间的相互作用受到许多科学家的研究。虽然已经对不同的化合物和材料进行了大量的研究，但对潜在的吸附机制仍缺乏普遍的了解。项目第一阶段的成果有助于提高该领域对碳纳米管的认识。开发了不同的模型，这些模型提供了有关吸附机理的信息，但它们仅对某些环境条件（pH，离子强度，温度）有效，并且不能转移到其他条件。文献中仅对有限数量的化合物和材料研究了环境条件对吸附的影响，其结果是，即使在这里，对潜在过程的一般理解仍然缺失。文献和项目第一阶段采用的批量实验存在平衡时间长、吸附剂用量有限的缺点，因此环境条件和材料特性的变化有限。在后续项目中，应继续进行吸附机理研究，并将重点转移到不同类型CNM吸附的变异性以及不同环境条件对吸附的影响上。为此，应开发一种基于柱的方法，该方法能够替代经典的批处理方法，从而使环境条件的变化更快，工作时间更短。首先，用验证的列研究了如何获得与批量实验可比较的结果。该方法建立后，利用各种山梨酸作为化学探针对不同的吸附剂进行表征。在不同的环境条件下进行吸附实验，研究这些参数对吸附的影响。这些测量结果在现有模型中实施或用于开发新模型，从而能够预测不同环境条件下有机化合物对CNM的吸附。基于改进的过程理解，与经典c18相相比，填充CNM的柱将作为分析化学领域分离的范例应用。

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.