LAUSR

Experimental investigations were carried out to examine the adsorption equilibrium, isotherm, kinetic behaviors of adsorption, and effect on adsorption-desorption of coal-bed methane (CBM) of the nonionic fluorocarbon surfactant (4-hydroxyethyl ether) (pentadecafluoro-alkyl) in the development process of CBM. The results show that the surfactant adsorption pattern is consistent with the Langmuir adsorption law for different rank coals, and the adsorption capacity is increasing from low-rank coal to high-rank coal. The surfactant adsorption process is spontaneous and endothermic, indicating that augmentation of temperature facilitates the adsorption of surfactant. The adsorption densities over electrolytes concentration on the surface of low-rank and medium-rank coal show the same trend; while for high-rank coal, it gives some details about the different trends. Adsorption densities decrease with pH value increasing of bulk solution for all coal samples. Adsorption behavior of surfactant is conducive to accelerating CBM desorption through wettability alteration of a coal surface.