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

碳纳米材料(CNM)对有机或无机化合物具有很强的吸附作用，因此它与有机或无机化合物之间的相互作用受到了许多科学家的研究。虽然已经对不同的化合物和材料进行了大量的批量实验研究，但对其潜在的吸附机制还缺乏普遍的了解。第一个项目阶段的成果有助于增进这一领域有关碳纳米管的知识。开发了不同的模型，提供了有关吸附机理的信息，但它们仅在某些环境条件(pH、离子强度、温度)下有效，不能转移到其他条件下。环境条件对吸附的影响在文献中只针对有限数量的化合物和材料进行了研究，其结果是，即使在这里，仍然缺乏对潜在过程的一般理解。文献和一期工程所采用的间歇实验存在平衡时间长、吸附剂用量有限等缺点，限制了环境条件和材料特性的变化。在拟议的后续项目中，应继续进行有关吸附的机械调查，重点转移到不同类型的CNM的吸附的可变性以及不同环境条件对吸附的影响。为此，应开发一种基于柱的方法，该方法能够取代经典的批处理方法，从而能够以较少的耗时工作更快地改变环境条件。首先，用经过验证的柱子研究如何获得与批处理实验相当的结果。该方法建立后，使用不同的脱附剂作为化学探针来表征不同的脱附剂。在不同的环境条件下进行吸附实验，考察这些参数对吸附的影响。这些测量的结果被应用于现有的模型或用于开发新的模型，从而能够预测不同环境条件下有机化合物在CNM上的吸附。基于改进的过程理解，与经典的C18相相比，填充CNM的色谱柱将被示范应用于分析化学领域的分离。

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.