Study On Modification Of Coal Gasification Slag And Its Adsorption Performance

Coal gasification slag has become another high-yield solid waste besides fly ash.Therefore,the coal gasification slag needs to be developed and utilized to achieve the purpose of treating waste with waste.Microwave modification,chemical modification,microwave-assisted chemical modification,rare earth loading,and microwave-assisted rare earth loading were carried out separately,and the influence of various influencing factors on the adsorption effect was explored.At the same time,the adsorption mechanism was studied,and SEM,FTIR,Characterization methods such as XRD and BET explore the mechanism of Cr6+and Congo Red(CR)adsorption by the adsorbent in more depth.The specific results are as follows:(1)The surface of the raw coal gasification slag is smooth and the particle size increases,the maximum ratio is 70.681m2/g.After modification by various methods,the ratio of the coal gasification slag increases to the increased range,the surface is rough and a part of the overlap is formed structure,exposed to a small amount of adsorption sites,the ratio increased to 134.518m2/g after microwave modification,the ratio increased to 87.364m2/g after microwave-assisted chemical modification,and the ratio increased to 90.631m2/g after microwave-assisted residue.Therefore,different modification methods for coal gasification waste residues improve the adsorption performance of impurities.(2)Microwave modification,chemical modification and microwave-assisted chemical modification of raw coal gasification,rare earth loading and microwave-assisted rare earth loading are the best reaction conditions for Cr6+adsorption:adsorption time is 120min,pH value 5,adsorption The dosage of the agent is 0.3g,the temperature is 30?,and the initial concentration is 100mg/L.At this time,the effect of the adsorbent on Cr6+adsorption is from high to low:microwave assisted rare earth loading>microwave assisted chemical modification>microwave modification>coal gasification slag.The corresponding adsorption quantity of the raw coal gasification slag are 25.15mg/g,15.58mg/g,9.95mg/g and 5.44mg/g,respectively.The optimal reaction conditions for adsorption of CR:adsorption time is 180min,pH value 7,adsorbent dosage is 0.1g,temperature is 30?,initial concentration is 500mg/L,and the effect of adsorbent adsorption CR is from high to low was,microwave-assisted rare earth loading>microwave-assisted chemical-modification>microwave-modification>coal gasifi-cation slag respectively,the corresponding adsorption amounts are 353.56mg/g,96.83mg/g,86.67mg/g and 55.97mg/g,respectively.(3)The adsorption process of Cr6+ and CR by raw coal gasification slag,microwave modified coal gasification slag,chemical modification and microwave-assisted chemical modification coal gasification slag,and rare earth load and microwave assisted rare earth load coal gasification slag are all in compliance with second-order adsorption kinetic model,the R2 is greater than 0.99.It is consistent with the Langmuir adsorption isotherm model,that is,the adsorption behavior is monolayer adsorption.The results of adsorption thermodynamics indicate that the adsorption process replaces the spontaneous exothermic reaction.After 4 times of desorption regeneration,the adsorbent still maintains a high adsorption performance.