Next Article in Journal
Silver Nanoparticles Functionalized with Sodium Mercaptoethane Sulfonate to Remove Copper from Water by the Formation of a Micellar Phase
Previous Article in Journal
Development of a Modified QuEChERS Procedure for the Isolation of Pesticide Residues from Textile Samples, Followed by GC–MS Determination
Article

Adsorption Characteristics and Mechanism of Calcium Ions on Different Molybdenite Surfaces via Experiments and DFT Simulations

1
Department of Mechanical and Electrical Engineering, Shandong University of Science and Technology, Qingdao 266590, China
2
Henan Province Industrial Technology Research Institution of Resources and Materials, Zhengzhou University, Zhengzhou 450066, China
3
College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao 266590, China
*
Author to whom correspondence should be addressed.
Separations 2021, 8(8), 107; https://doi.org/10.3390/separations8080107
Received: 25 May 2021 / Revised: 16 July 2021 / Accepted: 20 July 2021 / Published: 24 July 2021
Calcium ions are common in flotation process water, and have a significant effect on the molybdenite floatability, making separation of molybdenite from other minerals more difficult. Therefore, to improve the separation selectivity, the research of how calcium ions affect the molybdenite surface properties is of great significance. In this study, various methods including flotation tests, contact angle measurements, batch adsorption tests and Density Functional Theory (DFT) simulations were carried out to understand the adsorption characteristics and mechanism. Results of the contact angle measurements showed that the inhibition effects of calcium ions on molybdenite flotation kinetics were mostly attributed to the decrease of the edge surface hydrophobicity, as the contact angle of the edge surface decreased more than the face surface after treatment with calcium ions. While fitting the results of batch adsorption tests with adsorption kinetics and isotherm models, it was found that the Lagergen pseudo-first-order equation and the Freundlich isotherm model nicely follow the experimental trend. Moreover, DFT calculation results indicated that both Ca2+ and CaOH+ preferentially adsorb on the molybdenite (100) surface, particularly the edge surface, which was consistent with the contact angle results. Ca2+ adsorbed on the Mo-top site on the S-(100) surface by forming Ca-S bonds, transferring electrons from Ca 3d orbitals to S 3p orbitals. CaOH+ adsorbed on the S-top site of Mo-(100) surface by forming a strong covalent Mo-O bond and S-Ca bond. The results provide a basis for understanding and improving the separation effect of molybdenite from other minerals in the presence of calcium ions. View Full-Text
Keywords: calcium ions; molybdenite surfaces; DFT; adsorption mechanism calcium ions; molybdenite surfaces; DFT; adsorption mechanism
Show Figures

Figure 1

MDPI and ACS Style

Sun, L.; Cao, Y.; Li, L.; Zeng, Q. Adsorption Characteristics and Mechanism of Calcium Ions on Different Molybdenite Surfaces via Experiments and DFT Simulations. Separations 2021, 8, 107. https://doi.org/10.3390/separations8080107

AMA Style

Sun L, Cao Y, Li L, Zeng Q. Adsorption Characteristics and Mechanism of Calcium Ions on Different Molybdenite Surfaces via Experiments and DFT Simulations. Separations. 2021; 8(8):107. https://doi.org/10.3390/separations8080107

Chicago/Turabian Style

Sun, Liqing, Yijun Cao, Lin Li, and Qingliang Zeng. 2021. "Adsorption Characteristics and Mechanism of Calcium Ions on Different Molybdenite Surfaces via Experiments and DFT Simulations" Separations 8, no. 8: 107. https://doi.org/10.3390/separations8080107

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
Back to TopTop