Quantum chemistry investigation on influence of substituted carbonconcentration on the hydrophobicity of coal-pyrite surface

Abstract

The surface hydrophobicity of coal pyrite is enhanced because of doping with carbon atoms.In order to remove pyrite from coal,it is very important to analyze the influence of substituted carbon concentration on the hydrophobicity of coal-pyrite surface.Density functional theory and plane wave pseudopotential method are used to simulate the influence of the doping concentration of carbon atoms on the surface hydrophobicity of coal based pyrite.The simulation results show that compared with the perfect surface,the adsorption strength of water molecule on the pyrite surface substituted by carbon atoms became weaker with the increase of carbon atoms.The Mulliken population of Fe-O bond after H2O adsorption decreased.The S-H bond became C-H bond and its population also decreased.Meanwhile the electron density among the atoms of forming bond reduced.It illustrated that the strength of Fe-O、S-H/C-H became weaker with the increase of carbon atoms.The hydrophilism of pyrite surface substituted by carbon atoms became weak with the increase of carbon atoms and easier to float in the process of coal slime flotation.The mechanism of the influence of substituted carbon atoms on the hydrophobicity of pyrite surface was revealed from the view of quantum chemistry.

Keywords

• coal pyrite
• carbon impurity
• hydrophobicity
• quantum chemistry
• density functional theory