Carbon nanotubes (CNTs) and graphene play an essential role in nanotechnology. Accurate knowledge of their structure-activity relationship is prerequisite to designing fine-tuned nanomaterials. Furthermore, understanding interactions between organic contaminants and CNTs is critical to both the environmental application of CNTs as special adsorbents and the assessment of the potential impact of CNTs on the transportation of organic compounds in the environment. Here we have employed standard molecular dynamics simulations, as well as center-of-mass pulling and umbrella sampling, to study the thermodynamics of adsorption and containment of aromatic organic compounds, namely toluene and phenol molecules. The containments of the organic compounds inside different chiralities and diameters of single-walled carbon nanotubes (SWNTs) at the room temperature were evaluated. Results indicate that the free energy required to pull the molecule out of 20Å diameter SWNTs was still much larger than a thermal fluctuation at the room temperature. For this reason, both toluene and phenol molecules cannot escape from the investigated SWNTs without some external force. Based on the fact that both toluene and phenol are stable within CNTs at the standard condition, this study suggests several possible industrial applications, such as a usage of CNTs to separate organic molecules from various environments, such as removing of organic compounds from contaminated water after oil spills.

Thermodynamics study of absorption of aromatic organic compounds to carbon nanotubes

251st National Meeting (2016)

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