Experimental and Theoretical Estimations of Atrazine's Adsorption in Mangosteen-Peel-Derived Nanoporous Carbons

by Selleckchem | Nov 06 2023

Nanoporous carbons were prepared via chemical and physical activation from mangosteen-peel-derived chars. The removal of atrazine was studied due to the bifunctionality of the N groups. Pseudo-first-order, pseudo-second-order, and intraparticle pore diffusion kinetic models were analyzed. Adsorption isotherms were also analyzed according to the Langmuir and Freundlich models. The obtained results were compared against two commercially activated carbons with comparable surface chemistry and porosimetry. The highest uptake was found for carbons with higher content of basic surface groups. The role of the oxygen-containing groups in the removal of atrazine was estimated experimentally using the surface density. The results were compared with the adsorption energy of atrazine theoretically estimated on pristine and functionalized graphene with different oxygen groups using periodic DFT methods. The energy of adsorption followed the same trend observed experimentally, namely the more basic the pH, the more favored the adsorption of atrazine. Micropores played an important role in the uptake of atrazine at low concentrations, but the presence of mesoporous was also required to inhibit the pore mass diffusion limitations. The present work contributes to the understanding of the interactions between triazine-based pollutants and the surface functional groups on nanoporous carbons in the liquid-solid interface.

Comments:

The passage describes a study conducted on nanoporous carbons derived from mangosteen-peel chars. The objective of the study was to investigate the removal of atrazine, a type of triazine-based pollutant, using these carbons. The researchers focused on the role of nitrogen (N) groups present on the carbon surface, as they exhibit bifunctionality and can potentially interact with atrazine molecules.

To understand the kinetics of the atrazine adsorption process, the researchers analyzed different kinetic models, including pseudo-first-order, pseudo-second-order, and intraparticle pore diffusion models. These models help determine the rate at which atrazine molecules are adsorbed onto the carbon surface.

The researchers also examined the adsorption isotherms, which provide information about the equilibrium adsorption capacity of the carbons. Two commonly used models, the Langmuir and Freundlich models, were employed to analyze the adsorption isotherms and understand the nature of the adsorption process.

To compare the performance of the mangosteen-peel-derived carbons with commercially available activated carbons, the researchers used carbons with similar surface chemistry and porosity. The results indicated that the carbons with a higher concentration of basic surface groups exhibited the highest atrazine uptake.

Additionally, the researchers experimentally estimated the contribution of oxygen-containing groups on the carbon surface to the removal of atrazine. They determined the surface density of these groups and compared the results with the theoretically estimated adsorption energy of atrazine on graphene. The adsorption energy calculations were conducted using periodic density functional theory (DFT) methods. The findings revealed that the experimental results and theoretical estimations followed a similar trend: atrazine adsorption was more favorable at higher pH levels, indicating the importance of basic surface groups.

Furthermore, the study highlighted the significance of micropores and mesopores in the atrazine uptake process. Micropores were found to play a crucial role in the adsorption of atrazine at low concentrations, while the presence of mesopores was necessary to prevent limitations caused by mass diffusion within the pores.

Overall, this research contributes to the understanding of the interactions between triazine-based pollutants like atrazine and the surface functional groups present on nanoporous carbons in the liquid-solid interface.