Next Article in Journal
Confined Bed Breakage of Fine Iron Ore Concentrates
Next Article in Special Issue
Atomic Structure, Electronic and Mechanical Properties of Pyrophyllite under Pressure: A First-Principles Study
Previous Article in Journal
Fluid Evolution, H-O Isotope and Re-Os Age of Molybdenite from the Baiyinhan Tungsten Deposit in the Eastern Central Asian Orogenic Belt, NE China, and Its Geological Significance
Open AccessArticle

Role of Mg Impurity in the Water Adsorption over Low-Index Surfaces of Calcium Silicates: A DFT-D Study

by 1,2,3, 1,* and 2
1
School of Resources and Safety Engineering, Central South University, Changsha 410083, China
2
School of Civil, Environmental and Mining Engineering, University of Western Australia, Perth 6009, Australia
3
School of Molecular Sciences, University of Western Australia, Perth 6009, Australia
*
Author to whom correspondence should be addressed.
Minerals 2020, 10(8), 665; https://doi.org/10.3390/min10080665
Received: 5 June 2020 / Revised: 2 July 2020 / Accepted: 21 July 2020 / Published: 26 July 2020
(This article belongs to the Special Issue First Principles Calculations of Minerals and Related Materials)
Calcium silicates are the most predominant phases in ordinary Portland cement, inside which magnesium is one of the momentous impurities. In this work, using the first-principles density functional theory (DFT), the impurity formation energy (Efor) of Mg substituting Ca was calculated. The adsorption energy (Ead) and configuration of the single water molecule over Mg-doped β-dicalcium silicate (β-C2S) and M3-tricalcium silicate (M3-C3S) surfaces were investigated. The obtained Mg-doped results were compared with the pristine results to reveal the impact of Mg doping. The results show that the Efor was positive for all but one of the calcium silicates surfaces (ranged from −0.02 eV to 1.58 eV), indicating the Mg substituting for Ca was not energetically favorable. The Ead of a water molecule on Mg-doped β-C2S surfaces ranged from –0.598 eV to −1.249 eV with the molecular adsorption being the energetically favorable form. In contrast, the Ead on M3-C3S surfaces ranged from −0.699 eV to −4.008 eV and the more energetically favorable adsorption on M3-C3S surfaces was dissociative adsorption. The influence of Mg doping was important since it affected the reactivity of surface Ca/Mg sites, the Ead of the single water adsorption, as well as the adsorption configuration compared with the water adsorption on pristine surfaces. View Full-Text
Keywords: calcium silicates; first-principles DFT; Mg doping; water adsorption; structural and electronic properties calcium silicates; first-principles DFT; Mg doping; water adsorption; structural and electronic properties
Show Figures

Graphical abstract

MDPI and ACS Style

Qi, C.; Chen, Q.; Fourie, A. Role of Mg Impurity in the Water Adsorption over Low-Index Surfaces of Calcium Silicates: A DFT-D Study. Minerals 2020, 10, 665. https://doi.org/10.3390/min10080665

AMA Style

Qi C, Chen Q, Fourie A. Role of Mg Impurity in the Water Adsorption over Low-Index Surfaces of Calcium Silicates: A DFT-D Study. Minerals. 2020; 10(8):665. https://doi.org/10.3390/min10080665

Chicago/Turabian Style

Qi, Chongchong; Chen, Qiusong; Fourie, Andy. 2020. "Role of Mg Impurity in the Water Adsorption over Low-Index Surfaces of Calcium Silicates: A DFT-D Study" Minerals 10, no. 8: 665. https://doi.org/10.3390/min10080665

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop