engleski

Modeling the adsorption of emerging contaminants on carbon nanomaterials

By now, the presence of trace amounts of a wide range of contaminants introduced through wastewaters and their adverse effects on the environment have received considerable attention. Many advanced wastewater treatments have been considered in the search for an effective yet economical method for their removal of which adsorption has shown promise both as a direct method of contaminant removal and as means to increase the efficiency of other, oxidation based, methods. Due to the specific requirements of experimental studies on the adsorption of contaminants to carbon nanomaterials information on the thermodynamics of adsorption and more in-depth investigations of mechanisms which contribute to adsorption is available sparingly. Computational approaches enable this information to be obtained at, relatively, low cost in terms of the time required and for contaminants that may not otherwise be easily acquirable. In this study we model the adsorption of 69 pharmaceutically active compounds (PhACs) on the carbon nanomaterials (CNMs) graphene and graphene oxide, in water and n-octanol, in three pH ranges. We examine the relationship of non-covalent interactions (van der Waals, π-interactions, hydrogen bonding and hydrophobic interactions) and find differences in optimal removal conditions for the different classes of PhACs. The effect of temperature on the subsequent adsorbent regeneration is also discussed. Finally, as the data obtained is not influenced by the differences in nanomaterial composition introduced by variations in the protocol of its synthesis, it may further contribute to towards the development of predictive adsorption models.

emerging contaminants ; adsorption ; carbon nanomaterials ; density functional theory

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