Surface Properties of Macerals from Shenfu Coal

To investigate the floatability of macerals of the Shenfu coal,the proximate analysis,ultimate analysis,X-ray photoelectron spectroscopy(XPS),wetting heat and surface potential properties of vitrinite and inertinite samples were measured.The results show that the chemical composition,structure and the physicochemical property of vitrinite and inertinite are similar.The hydrophobic and hydrophilic groups co-exist in these maceral samples,and the oxygen containing functional groups influence the wetting property of maceral significantly.The oxygen-carbon mass ratio of polar oxygen containing functional group in vitrinite is 0.135,within which 0.090 is from the hydroxyl,and those of inertinite are 0.112 and 0.061 respectively.Therefore,the vitrinite shows less hydrophobicity,which is in contrast to some information given in published papers.The wetting heat of inertinite in double de-ionized water is 9.639 J/g,and that of vitrinite is-21.306 J/g.Both vitrinite and inertinite carry negative charges on their surfaces in a wider range of pH values.The ξ-potentials of inertinite and vitrinite have little difference,and the pH values of their zero-potential points are 2.80 and 3.40.