Sorption of organic chemicals by carbonaceous nanomaterials

Importance of the work and objectives. With increasing production and use of carbon nanomaterials (CNMs), they will inevitably be released to the environment. Once released into the environment, CNMs would interact with... [ view full abstract ]

Importance of the work and objectives. With increasing production and use of carbon nanomaterials (CNMs), they will inevitably be released to the environment. Once released into the environment, CNMs would interact with organic pollutants (OPs) upon contact. Due to large surface area and highly hydrophobic nature of CNMs, they have been proposed as a promising sorbent for removing environmental pollutants. To help better understand the interaction difference between OPs and carbonaceous materials on site energy respect, the site energy distribution analysis was conducted to probe sorption behaviors of naphthalene, lindane, and atrazine on ten sorbents with different physical structure and chemical composition.
Materials and methods. Naphthalene, lindane, and atrazine were selected as sorbates. Ten kinds of carbonaceous materials with considerably different physical structure and chemical composition were used as sorbents.
Main results and conclusion. Introduction of O-containing functional groups to the sorbents decreased their average sorption energy for the studied compounds. However, relative to the decrease in average site energy, the reduction in number of sorption sites as indicated by surface area more strongly reduced sorption capacity of the tested compounds to the carbonaceous materials used based on the result of the linear regression analysis. Sorption site heterogeneity of the sorbents decreased as their oxygen contents increased. The better dispersion of the sorbents with higher oxygen-containing moieties as shown by TEM images could be the reason for their more homogeneous sorption site energy distribution. These findings are critical for better understanding of the sorption mechanisms of OPs to carbonaceous materials.