In the past decades, the adsorption mechanisms of amine pollutants on carbonaceous materials have been widely studied via batch sorption experiments and spectroscopic methods. However, the data obtained by these techniques reflects the changes of the adsorbent and the concentrations of the pollutants before and after the reaction, which lacks characterizations of in-situ interactions between amine and adsorbents. To comprehend the adsorption mechanisms in real time, herein we introduced an AFM (atomic force microscopy)-based force spectroscopy to quantitatively determine the molecular interactions of methylamines and N-methylaniline on graphite surface in situ, which combines density functional theory (DFT) to verify reliability of the experiments. The results showed that the molecular interactions of amines on graphite surface were impacted by pH values. Our study broadens the comprehension on cation-π interaction between amines and electron-rich aromatic compounds in microscale. Furthermore, an AFM-based force spectroscopy was established to achieve direct measurements of molecular interactions between amine pollutants and sorbent materials in situ, which needs smaller amounts of samples and acquires more details comparing to the conventional sorption experiments and spectroscopic methods.

Quantitative determination of intermolecular attraction between amines and graphene using AFM force spectroscopy

2019 Fall National Meeting

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