Journal of Hazardous Materials, Vol.263, 550-555, 2013
Evaluating the interactions of organic compounds with multi-walled carbon nanotubes by self-packed HPLC column and linear solvation energy relationship
Understanding the interactions between organic pollutants and carbon nanotubes (CNTs) is critical for fate assessment of both CNTs and organic pollutants. In this study, the chromatographic approach was introduced based on CNTs as stationary phase for the evaluation of such interactions. The pristine multi-walled carbon nanotubes (MWCNTs) were packed into columns of high-pressure liquid chromatography (HPLC) and the retention factors (k') were determined to characterize the adsorption affinity of organic compounds onto MWCNTs. Nine compounds were tested. The results showed that their ln k' values followed the order: benzene < toluene < phenol < chlorobenzene < bromobenzene < aniline < sulfamethoxazole < sulfadiazine approximate to sulfadimidine. The linear solvation energy relationship (LSER) theory was adopted to correlate ln k' with the molecular solvatochromic parameters. We found that ln k' of the studied compounds correlate positively with molecular polarizability (E) significantly, suggesting that the pi-/n-electrons-dependent polarizable interactions play a major role for the adsorption. Moreover, the thermodynamic parameters calculated from van't Hoff equations revealed that the interactions between the compounds and MWCNTs were spontaneous and exothermic processes. (C) 2013 Elsevier B.V. All rights reserved.