Effect of bio-based surfactant on wettability of low-rank coal surface and its mechanism.

In this study, the effect of a bio-based environment-friendly surfactant, cardanol polyoxyethylene ether (BGF), on the wettability of the surface of low-rank coal (LRC) and its mechanism were studied. The adsorption experiment showed that the adsorption of the surfactant conformed to the Langmuir adsorption model and the pseudo-second-order kinetic model. The adsorption was mainly affected by hydrogen bonding, and the adsorption rate was affected by intraparticle diffusion and liquid film diffusion. The wettability experiment showed that the influence of BGF on the wettability of the surface of LRC followed the given order: BGF-7 > BGF-10 > BGF-15. The investigation of adhesion work showed that the adhesion work and the stability of the coal-water system decreased after adsorption. Fourier transform infrared and X-ray photoelectron spectroscopy analyses showed that after adsorption, the peak strength of vinyl ether, the content of elemental carbon, and the content of C-C/C-H groups increased.