Study On The Effect Of Ultraviolet Light On Surface Oxidation Of Coal

The surface oxidation extent has a crucial effect on the performance and way of using coal.Currently,the surface oxidation affect the coal application owning to the continuous consumption of high-quality coal resources and the increasing using of weathered and oxidized coal from poor Seam Occurrence Conditions.Thus taking advantage of using the oxidation of coal with purpose and improving the utilization efficiency of coal has already become the main research subject in the filed of using coal with high efficiency.The main principle is using the ultraviolet light and other means of treatment together,by the destruction of coal aromatic hydrocarbons and carbonyl and other structures,and oxygen combined with carboxyl,hydroxyl and other oxygen-containing groups to achieve the purpose of oxidizing coal surface.This research,taking Majialiang CY coal as sample,has studied the effects of acid treating,Metal ion loading,photosensitizer adding in the oxidation under ultraviolet light etc by measuring the contact angle,Zeta potential,infrared and thermogravimetric analysis of sample before and after the reaction.And then we we compare and analysis the results,thus the following results has been achieved from the reaction mechanism:1.The maximum oxidation effect generally occurs with UV light irradiation time 2h when the sample surface hydrophobicity reaches the lowest;And through further infrared and thermogravimetric analysis we can see that the UV light can be destruct macromolecule structure in coal,causing the destruction of the organic structure of the coal,while catalyzing the hydrolysis of the ester orether in the coal to —OH and—COOH,which eventually leads to the oxidation of the coal surface.It also shows that the UV-Mineral composition basically has no oxidation,but an appropriate amount of inorganic minerals contained in coal will propoting oxidation under UV.2 When different substances were used for coal surface modifacation,the effect of oxidation under UV is different.Mg2+?Fe3+?Sn2+ and Cu2+are all reduced the contact angle of oxidized coal under UV light.The effect of Sn2 mainly causes the destruction of aromatic hydrocarbon structure,meanwhile with the adding of C=O and — OH and other oxygen-containing functional groups.Na + and sodium stearate can prevent the surface oxidation of coal under UV.With adding TiO2 and UV environment,mainly —S=O and —C=O is destroyed,generating — S — O and-C-O,resulting in coal surface oxygen atoms increased,and thus the sample Is oxidized.3.Ultrasonic treatment can accelerate the coal oxidation process mainly by increasing the dissolved oxygen in water,and cleaning the coal surface.It can achieve synergistic effect combining with ultraviolet light oxidation,but the effect is limited by oxygen content in liquid.