scholarly journals Effect of Hydration Layer on the Adsorption of Dodecane Collector on Low-Rank Coal: A Molecular Dynamics Simulation Study

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1207
Author(s):  
Lingyun Liu ◽  
Erle Qiao ◽  
Liang Shen ◽  
Fanfei Min ◽  
Changguo Xue
Keyword(s):  
Molecular Dynamics ◽  
Dynamics Simulation ◽  
Low Rank ◽  
Surface Model ◽  
Coal Surface ◽  
Low Rank Coal ◽  
Hydration Layer ◽  
Flotation Process ◽  
Pass Through ◽  
Water Collector

The hydration layer has a significant effect on the adsorption behavior of reagents during the flotation process of low-rank coal. Understanding the effect of hydration layer on the adsorption of common collectors on low-rank coal is a prerequisite for proposing a new enhanced coal floatation method. In this study, a smooth low-rank coal surface model with a density of 1.2 g/cm3 was constructed and compared with the XPS results. Three different systems, coal-water, coal-collector, and coal-water-collector, were constructed. Molecular dynamics method was applied to study the adsorption behaviors of water and dodecane molecules. Simulation results revealed that a stable hydration layer with a thickness of about 5 Å was formed due to the strong attraction of coal surface. The negative value of interaction energy (IE) indicated that dodecane molecules could spontaneously adsorb on the coal surface. Dodecane molecules were successfully adsorbed on the coal surface when it was located inside the hydration layer. While the dodecane molecule was outside the hydration layer, it could not pass through the hydration layer on the surface of low-rank coal.

scholarly journals Adsorption Behavior of Methyl Laurate and Dodecane on the Sub-Bituminous Coal Surface: Molecular Dynamics Simulation and Experimental Study

Minerals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 30 ◽  
Author(s):  
He Zhang ◽  
Wenli Liu ◽  
Hongxiang Xu ◽  
Qiming Zhuo ◽  
Xiaopeng Sun
Keyword(s):  
Molecular Dynamics ◽  
Bituminous Coal ◽  
Ester Group ◽  
Adsorption Behavior ◽  
Dynamics Simulation ◽  
Low Rank ◽  
Methyl Laurate ◽  
Head Group ◽  
Coal Surface ◽  
Liquid Environment

Biodiesel was found to be a more effective collector on low-rank coal flotation than the common oily collectors (diesel and kerosene) in previous research. However, the micro-adsorption behavior of these collectors on the coal surface remains to be further explored. In the present work, the adsorption behavior of methyl laurate and dodecane, representing biodiesel and common oily collectors, was investigated using experimental and molecular dynamics (MD) simulation methods. The results of MD simulations showed that dodecane was difficult to diffuse on the surface of sub-bituminous coal and formed a spherical structure on the surface of sub-bituminous coal. Methyl laurate was adsorbed on the surface of coal via the head group (ester group), while the tail group (alkyl chain) was exposed to a liquid environment, forming a wider network structure on the coal surface. The above results, mainly attributed to methyl laurate, had a higher interaction with the sub-bituminous surface compared to dodecane. The self-diffusion coefficient results showed that the aggregate configurations of methyl laurate cause higher water mobility, which was more conducive to enhancing the hydrophobicity of the coal surface. The adhesion efficiency measurement and X-ray photoelectron spectrometer (XPS) analysis confirmed that methyl laurate could cover more oxygen-containing functional groups on the coal surface than dodecane, thus enhancing the hydrophobicity of coal. The results of simulations conformed to the experimental results.

Experimental and molecular dynamics simulation study on the enhancement of low rank coal flotation by mixed collector

Fuel ◽  
2020 ◽  
Vol 266 ◽  
pp. 117046 ◽  
Author(s):  
Lei Zhang ◽  
Xiaole Sun ◽  
Bao Li ◽  
Zhixuan Xie ◽  
Jianying Guo ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Simulation Study ◽  
Dynamics Simulation ◽  
Low Rank ◽  
Low Rank Coal ◽  
Coal Flotation

Adsorption and molecular dynamics simulations of nonionic surfactant on the low rank coal surface

Fuel ◽  
2018 ◽  
Vol 211 ◽  
pp. 529-534 ◽  
Author(s):  
Xianjun Lyu ◽  
Xiaofang You ◽  
Meng He ◽  
Wei Zhang ◽  
Hengbin Wei ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Nonionic Surfactant ◽  
Low Rank ◽  
Coal Surface ◽  
Low Rank Coal ◽  
Dynamics Simulations
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