Density functional theory study of hydrophobic zeolites for the removal of triclosan from aqueous solution

24 May 2023, Version 2
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

The chlorinated biphenyl ether triclosan (TCS), used as a disinfectant in health care settings and in various personal care products, is an emerging organic contaminant of significant concern. Adsorption-based methods have been proposed as one potential pathway for the removal of TCS from wastewaters. Hydrophobic high-silica zeolites could constitute suitable adsorbent materials for such applications. In order to gauge the impact of pore size, topology, and framework composition, the adsorption of TCS in six different all-silica zeolites (AFI, BEA, CFI, FAU, IFR, MOR frameworks) and two highly siliceous protonated zeolites (H-FAU, H-MOR) was investigated using dispersion-corrected density functional theory (DFT). While pore size was found to affect the interaction strength, the rather flexible TCS molecule can adjust to different pore shapes, resulting in very similar adsorption energies for most all-silica zeolites. Although the interaction with TCS is enhanced in protonated zeolites, the affinity towards water increases even more. In DFT-based molecular dynamics simulations of TCS and water co-adsorption, H2O molecules quickly replace TCS in the vicinity of the framework protons, deprotonating the framework and forming positively charged clusters. In addition to delivering atomic-level insights into TCS adsorption, the calculations indicate that a fine-tuning of pore size with a concurrent maximization of hydrophobicity should constitute a promising strategy to develop optimized zeolite adsorbents for TCS removal.

Keywords

emerging contaminants
adsorption
zeolites
density functional theory
host-guest interactions

Supplementary materials

Title
Description
Actions
Title
Supporting Information PDF
Description
Details of calculations and additional tables and figures
Actions
Title
Models of H-FAU and H-MOR
Description
ZIP archive containing DFT-optimized models of protonated zeolites H-FAU and H-MOR
Actions
Title
AIMD simulations: TCS
Description
ZIP archive containing results of AIMD simulations of TCS
Actions
Title
AIMD simulations: TCS adsorption in FAU
Description
ZIP archive containing results of AIMD simulations of FAU and TCS@FAU
Actions
Title
AIMD simulations: TCS adsorption in MOR
Description
ZIP archive containing results of AIMD simulations of MOR and TCS@MOR
Actions
Title
AIMD simulations: TCS adsorption in H-MOR
Description
ZIP archive containing results of AIMD simulations of H-MOR and TCS@H-MOR
Actions
Title
AIMD simulations: TCS and H2O co-adsorption in H-FAU
Description
ZIP archive containing results of AIMD simulations of H2O@(TCS@H-FAU)
Actions
Title
AIMD simulations: TCS and H2O co-adsorption in H-MOR
Description
ZIP archive containing results of AIMD simulations of H2O@(TCS@H-MOR)
Actions
Title
Results of TZVP calculations
Description
ZIP archive containing results of TZVP single-point calculations
Actions
Title
AIMD simulations: TCS adsorption in H-FAU
Description
ZIP archive containing results of AIMD simulations of H-FAU and TCS@H-FAU
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.