Study On Adsorption Performance Of Roasting Modified Tail Coal For Heavy Metal Ions In Water

The amount of raw coal selected in the coal preparation plant is increasing year by year,and it is also accompanied by the discharge of a large amount of tail coal.,and it is also accompanied by the discharge of a large amount of tailings.Environmental hazards such as geological disasters.With the development of clean coal technology and the improvement of national requirements for environmental protection,the comprehensive treatment and utilization of flotation tailings discharged by coal preparation plants has become an important problem to be solved urgently.In this paper,roasting treatment is used to modify three kinds of flotation tailings with different metamorphisms,and the adsorption reaction temperature,solution p H value,roasting modification temperature on Cr(VI),Cu(II),Pb(II)in water The effect of the adsorption of three heavy metal ions.The physical and chemical properties of the prepared adsorbent were characterized by XRD analysis,FTIR infrared spectroscopy analysis,SEM-EDS analysis,MLA analysis and nitrogen adsorption.The main conclusions of this article are as follows:(1)Three kinds of flotation tail coals with different metamorphism degrees were selected for ash content test and particle size composition analysis.It was found that coking coal-based flotation tail coal had the largest ash content and the smallest particle size.The minimum particle size of coal ash is the largest.According to the adsorption test,it can be concluded that the larger the ash content and the smaller the particle size,the more favorable the adsorption reaction is.According to XRD analysis,the three tail coals contain kaolinite,illite,quartz,calcite and other substances.(2)Among the three types of flotation tailings with different metamorphisms,coking coal flotation tailings have the best adsorption effect,followed by gas coal flotation tailings,and anthracite flotation tailings adsorption capacity is the weakest.Ash and particle size affect the adsorption effect.It can be concluded from the adsorption experiment that the adsorption of Cr(VI),Cu(II)and Pb(II)by flotation tailings complies with the Langmuir adsorption isotherm equation and quasi-second-order kinetic equation.Increasing the reaction temperature is beneficial to the adsorption process and belongs Endothermic reaction.The p H value of the solution has a great influence on the adsorption effect.The flotation tail coal has the strongest adsorption capacity when the modified roasting temperature is 800 ?.The adsorption rate of Cr(VI),Cu(II)and Pb(II)can reach more than 90%.(3)After roasting and activation treatment,the oxygen-containing functional groups in the tail coal are greatly reduced,the electronegativity of the tail coal surface is weakened,and the electrostatic attraction is significantly enhanced.Obvious porous and fluffy structure is produced on the surface.The content of kaolin in the mineral composition has decreased,while the content of illite has obviously increased.Among the three tail coals,the modified coking coal has the largest specific surface area and pore volume,followed by modified gas coal,and the modified anthracite has the smallest specific surface area and pore volume.This is consistent with the results of the adsorption test.The larger the specific surface area and pore volume of the adsorbent,the stronger the adsorption capacity of the adsorbent.The rich pore structure is conducive to the adsorption reaction.