Study On The Preparation Of Adsorbent Materials From Coal Gasification Crude Slag And The Application Of Treatment Of Heavy Metals And Ammonia Nitrogen In Water

The development of coal industry is an important measure for the country in adjusting the energy structure,and the rapid development of coal industry and the rapid progress of coal gasification technology have caused a lot of trouble.However,coal gasification residue(coarse and fine slag),as an important biomass resource,has become a current research hotspot in the field of coal and environment.The physicochemical properties of coal gasification residue differ greatly from those of conventional solid wastes such as fly ash,and the existing fly ash treatment process is difficult to achieve its efficient treatment.so there is an urgent need for systematic and in-depth theoretical and practical exploration of it.Therefore,in view of the problems in China’s coal industry,a theoretical and technological innovation of high value utilization and environmental management of solid waste using coal industry crude slag as raw material is proposed,which is of great practical significance to the advantageous and characteristic advantageous industries in China’s coal industry and the economic and social development of the Yellow River Basin.In this study,the raw material of Ning dong coal gasification crude slag is used to prepare coal gasification crude slag adsorbent by pretreatment and specific physical activation without high temperature and chemical reagents.Meanwhile.on the basis of physical activation,manganese oxide was used as a carrier and loaded with manganese oxide to prepare manganese oxide/coal gasification crude slag adsorbent,and the loading of manganese oxide could improve the porosity of adsorbent and the corresponding efficiency of treating ammonia nitrogen.The preparation method of manganese oxide/coarse gasification adsorbent is simple,and no pollutants are generated during the preparation process,meanwhile,the adsorption rate of ammonia nitrogen is high and reusable,which has a wide application prospect.The main findings of this paper are as follows:(1)Without any chemical reagent addition and without any other raw material addition,the coal gasification crude residue was activated by pretreatment ball milling to release a large number of reactive groups by etching layer by layer then the coal gasification crude residue was dried at 105 ℃.Then it was put into a planetary ball mill and etched by collision between balls and particles for 9 h.During the ball milling process,a large amount of heat was generated to form new groups on the surface,and the internal groups were also exposed gradually during the etching process.The IR analysis can be concluded that a large number of groups such as-COOH,C=O and-OH are added to its surface after activation.(2)The adsorption test of simulated wastewater containing heavy metals was carried out by using the horizontal oscillation method.The IR analysis before and after the adsorption reaction showed that the metal ions formed a similar structure of Cu-O with the surface functional groups,and the successful adsorption of metal ions on the adsorbent surface could be proved by map map and IR analysis.And the map diagram reveals that the acti ve sites bound to the adsorbent surface are different for different metal ions.The primary kinetics and secondary kinetics can be concluded that the adsorption of Cu and Pb ions is a combination of physical and chemical adsorption,while the chromium and cadmium ions in the wastewater are mainly chemical adsorption.The analysis of the fitted adsorption isotherms Langmuir and Freundlich revealed that the adsorbent is multilayer adsorption.Its saturation adsorption amounts for Pb ion.Cu ion,Cd ion and Cr ion were 192.56mg/g,110.15 mg/g,02.36 mg/g and 49.5 mg/g,respectively(3)The adsorption performance of this adsorbent was enhanced by loading manganese oxides on the basis of specific physical activation.The redox method was chosen to prepare the adsorbent of coal gasification crude residue loaded with manganese oxides,which has high electrostatic adsorption capacity for cationic pollutants due to its large specific surface area,high redox potential and negative surface charge.The adsorption factors affecting the simulated ammonia nitrogen wastewater were investigated,and the removal rate of ammonia nitrogen was 72.7%with a saturation adsorption capacity of 27.26 mg/g under the conditions of 5 g,reaction temperature at 25℃ and reaction time of 90 min.The adsorption capacity was 2.9 times higher than that of the crude coal gasification slag without manganese oxide loading(after specific physical activation).In addition,the removal rate remained at 75.3%after 5 consecutive cycles,indicating that the adsorbent can be reused.