engleski

Modelling of the adsorption of pharmaceutically active compounds on carbon-based nanomaterials

A wide range of pharmaceuticals enter water systems and consequently impact both aquatic and terrestrial ecosystems. Carbon based nanomaterials (CNMs) have emerged as effective next-generation adsorbents, receiving increasing attention due to their potential in water and wastewaters treatment applications. Understanding and acquiring knowledge about the adsorption of pharmaceuticals on CNMs is imperative to the chemical engineering applications of CNMs, as well as to risk assessment and pollution control of both CNMs and pharmaceuticals. Here we provide a computational assessment of the mechanism and thermodynamics of the adsorption of 18 most common pharmaceuticals on four different CNMs (pristine/functionalized graphene and carbon nanotube) in two different solvents (water and n-octanol). We show that the adsorption of pharmaceuticals on pristine CNMs is controlled by dispersion forces, π interactions and hydrophobic interaction. On the other hand, adsorption on functionalized CNMs is controlled by hydrogen bonding and Coulombic ionic interactions. Furthermore, we demonstrate how functionalization of CNM, CNM curvature and background solution properties modulate the intensity of non-covalent interactions and their contribution towards adsorption Gibbs free energy. With this knowledge, we pinpoint functionalized graphene at environmental pH as the most effective setting for the removal of a given set of PhACs from water and wastewater. Finally, we show that CNMs may transport pharmaceuticals into living organisms and release them in nonpolar mediums such as cellular membranes and fat cells. The obtained theoretical insights expand and complement experimental observations and provide important information which will contribute to further exploration into the adsorbent properties of CNMs, the evaluation of CNMs toxicity, and towards the development of predictive adsorption models.

pharmaceutically active compounds ; carbon-based nanomaterials ; adsorption ; density functional theory

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