Removal of toxic heavy metal ions from waste water using superchalcogens: A theoretical study. Issue 2 (April 2021)

• Record Type: Journal Article
• Authors: Omidvar, Akbar
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 2(2021)
• Publication Date: 2021-04
• Subjects: Superatom -- Superchalcogen -- Heavy metals -- Waste water treatment -- Density functional theory; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2020.104787
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: The first DFT study on the adsorption of pollutant Cd 2+, Hg 2+, and Pb 2+ cations on BeAl12 2− and TiAu12 2− superchalcoens. Detailed analysis of possible charge transfers between the cations and the superchalcogens. Creation of interesting nonlinear optical response materials for future applications. Abstract: One of the most exciting events in chemistry is the stable assemblies of atoms, denoted by superatoms, that could mimic the behaviors of elements in the periodic table. For the first time by Jena et al., a novel type of di-anions superchalcogens (BeAl12 2− and TiAu12 2- ) has been introduced based on the various electron-counting rules. Inspired by the fascinating finding of these superatoms and guided by density functional theory calculations, we propose a novel and efficient strategy to capture pollutants from waste water via adsorbing the toxic heavy metal cations (Cd 2+, Hg 2+, and Pb 2+ ) by the BeAl12 2− and TiAu12 2− superchalcogens. Our results reveal that the BeAl12 2− and TiAu12 2− superchalcogens were powerful to adsorb the Pb 2+, Hg 2+, and Cd 2+ cations in the aqueous solution. Furthermore, by investigating the hydrated cations, the adsorption of hydrated [Pb(H2 O)4 ] 2+ on the BeAl12 2− and TiAu12 2− superatoms was found thermodynamically more favorable than the [Cd(H2 O)4 ] 2+ and [Hg(H2 O)4 ] 2+ . Our calculations also showed that the adsorbing heavy metal cations can considerably narrow the wide HOMO-LUMO gap and remarkably enhance the first hyperpolarizability of the pristine BeAl12 2− and TiAu12 2− superchalcogens, due to electron transfer in this type of superatoms. Moreover, the results highlight the systems with higher electron transport rates, show the larger first hyperpolarizability as well as the higher nonlinear optical response. Time-dependent density functional calculations also revealed "ligand to metal charge transfer" vertical excitations for the cation/superchalcogen systems. However, these theoretical findings might be helpful for experimental scientists toward designing high-efficient adsorbents based on superatoms for eliminating water pollutants.