Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Mercury exchange in zeolites Na-A and Na-Y studied by classical molecular dynamics simulations and ion exchange experiments

Hernandez-Tamargo, Carlos, Kwakye-Awuah, Bright, O'Malley, Alexander J. and de Leeuw, Nora H. 2021. Mercury exchange in zeolites Na-A and Na-Y studied by classical molecular dynamics simulations and ion exchange experiments. Microporous and Mesoporous Materials 315 , 110903. 10.1016/j.micromeso.2021.110903

[thumbnail of 1-s2.0-S1387181121000287-main (1).pdf]
Preview
PDF - Published Version
Available under License Creative Commons Attribution.

Download (1MB) | Preview

Abstract

Classical molecular dynamics simulations have been employed to study the exchange of Na for Hg in zeolite Na-A, with a Si/Al ratio of 1, and zeolite Na-Y, with Si/Al ratios of 2 and 5, in dry and hydrated conditions within the temperature range 330 – 360 K, to understand factors underpinning the performance of zeolites for water decontamination. A classical forcefield based on DFT energies has been developed for the interaction between the Hg ions and the zeolite O atoms. In terms of water diffusion, zeolite Na-A shows the lowest calculated diffusivity, followed by zeolite Na-Y (Si/Al=2) and Na-Y (Si/Al=5), as a consequence of differing pore dimensions and extra-framework ion loadings. In the absence of speciation anions, the Hg ions are consistently adsorbed at the supercage windows in both the LTA and FAU framework types. The reduced pore size of zeolite A leads to an average hydration number per Hg ion of ¡1.0, whilst the wider pore of zeolite Y exerts less steric hindrance, and thus the Hg hydration number reaches values between 1.0 and 2.0 in zeolite Y. These observations might indicate that Hg ions are more strongly immobilized in zeolite A than in zeolite Y. Preliminary measurements of mercury removal using these zeolites, as synthesized from bauxite and kaolin, seem to support these findings.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Chemistry
Publisher: Elsevier
ISSN: 1387-1811
Funders: EPSRC, NERC
Date of First Compliant Deposit: 3 February 2021
Date of Acceptance: 14 January 2021
Last Modified: 18 Mar 2021 12:09
URI: https://orca.cardiff.ac.uk/id/eprint/138201

Citation Data

Cited 4 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics