Study On Wetting Effect And Microscopic Mechanism Of Lignite By Green Surfactant Complex

Lignite has abundant reserves and broad application prospects,but mining,transportation,loading and unloading will produce a large amount of coal dust,which not only pollutes the environment but also damages human health.In order to effectively moisten coal dust and achieve high efficiency dust removal,the wetting behavior of lignite with green surfactant was studied and the microscopic mechanism was studied.Through the analysis of the properties of various green surfactants,the materials with low price and wide application range were selected for the compound.Surface tension tester was used to determine the critical micellar concentration(CMC)of monomer,and fluorescence spectrophotometer was used to determine the CMC of the mixed system.The micellar properties,fluorescence intensity and solution polarity were analyzed by fluorescence spectrum,and the micellar properties of the monomer and mixed system were compared to verify the synergistic effect of the system and provide initial data parameters.Three factors and three levels orthogonal experiments were designed,and inorganic salt synergists were selected to enhance water retention and improve wettability.In order to determine the appropriate concentration gradient and avoid the waste of raw materials,the concentration gradient was set by referring to each CMC monomer,the influence of different concentration ratios on wettability was studied,and the settlement,contact Angle and surface tension experiments were designed.The corresponding experimental values were used as the test indexes of orthogonal design,and the wettability and penetration effects of the formula were discussed through the range analysis of data and macroscopic experimental phenomena.The optimal ratio is2.5g/L Decyl Glucoside,1g/L sodium fatty alcohol polyoxyethylene ether carboxylate,0.5g/L sodium chloride,2.5g/L Decyl Glucoside,0.04g/L sodium fatty acid methyl ester sulfonate,2g/L sodium chloride.Fourier infrared experiments were carried out on the complex system with infrared spectrometer.The infrared spectra were divided into four sections and Peak Fit and Origin software were used for peak fitting.The optimal wetting formula in all research schemes was further determined from the perspective of total changes of hydrophobic and hydrophilic functional groups.Namely,2.5g/L Decyl Glucoside,0.04g/L sodium fatty acid methyl ester sulfonate,2g/L sodium chloride.The molecular dynamics simulation of the system was carried out using Materials Studio software,and the micro-wetting mechanism of the complex green surfactant was deeply discussed.The adsorption configuration,relative concentration,radial distribution function,mean azimuth-shift and other parameters were analyzed,and the binding mode of coal and surfactant molecules,namely hydrophobic tail chain connection,was obtained.The hydrophilic head group is exposed to attract water molecules to adsorb and spread the surface of coal,and it is understood that the combination of components depends on hydrogen bonding and van der Waals force action,and the water molecules in the system with the presence of surfactants are more intense,which can effectively wet coal dust.