Preparation Of Mesoporous Materials By Gasification Fine Slag And Its Application In CO₂ Capture,Resin Reinforcement And Deodorizations

Based on the resource spread of“rich coal,poor gas,and less oil”in China,the use of coal resources and the development of related technologies are inevitable choices.With the rapid development of the coal chemical industry,China discharges a large amount of coal gasification slag every year,and the emission of coal gasification slag is increasing year by year.At present,the disposal method of coal gasification slag is only landfill,which not only occupies a lot of lands and causes environmental pollution but also causes waste of resources.Coal gasification slag is a kind of solid waste formed after coal is gasified at high temperatures and quenched by water in the gasifier.The special formation process makes coal gasification slag have a series of properties with high reactivity and unique particle morphology.This has laid a good foundation for its resource utilization.In this paper,the solid pollutant coal gasification fine slag was used as raw material,and after the in-depth study of its physical and chemical properties,adhering to the concept of using environmental pollutants to treat environmental problems,mesoporous materials with high specific surface area and high pore volume were successfully prepared,which were used in the adsorption of carbon dioxide and the reinforcement and deodorization of resin materials.This not only provides a new method for the recycling of coal gasification slag but also helps to solve the environmental problems and promote the process of carbon neutrality in the coal gasification industry.The main research contents of this paper can be summarized as follows:1.The mesoporous adsorption material CGFSA with a specific surface area of 541m² g^-1 and pore volume of 0.543 cm³ g^-1 was prepared by seving and acid leaching based on the characteristics of the high reactivity of coal gasification slag.Then,ethylenediamine(EDA),diethylenetriamine(DETA),triethylenetetetramine(TETA),and tetraethylenepentamine(TEPA)were loaded onto CGFSA by physical impregnation,and the mechanism of amine modification and CO₂ adsorption of the material were analyzed.The results showed that the interaction between CGFSA and the modifier mainly occurred through the silanol groups,and the higher the loading of organic amine,the more serious the blockage of the CGFSA pore channel.CGFSA-TEPA-20 has the best adsorption capacity for CO₂,with a theoretical maximum adsorption capacity of 132.5 mg g^-1 at 273 K.The fitting of the adsorption results shows that the adsorption of CO₂ by the material conforms to the Langmuir model and the Avrami kinetic model,and the isobaric heats of CO₂ by the materials is greatly increased after the amine modification,indicating that the adsorption of CO₂ on CGFSA is mainly physical adsorption.After amine modification,the proportion of physical adsorption of CO₂ by CGFSA-TEPA-20 decreases,and the chemical adsorption gradually increases.At the same time,after 10 adsorption/desorption cycles,the adsorption capacity of CGFSA-TEPA-20 for CO₂ decreased by only 10%,indicating that CGFSA-TEPA-20 has good cycle stability.2.Three siliceous mesoporous coal gasification slag materials,CGFS-F1,CGFS-F2,and CGFS-F3,were obtained by using acid leaching,calcination,decarburization,and sieving processes,and filled in PP resin.The results showed that the mechanical properties of the composites increased with decreasing particle size of CGFS-F,and the reinforcement effect of CGFS-F3 on PP resin was much higher than that of the 1250mesh calcium carbonate and commercially available deodorant.When the filler content was 30 wt%,the reinforcement effect of CGFS-F3 on the tensile,flexural,and impact strength of PP resin is 49.8%,139.6,and 70.8%higher than that of 1250 mesh calcium carbonate,respectively;the reinforcement effect of CGFS-F3 on the tensile,flexural and impact strength of PP resin is 86.3%,118.7and 120.6%higher than that of commercially available deodorant,respectively.The reasons were analyzed from the aspects of micromorphology,stress concentration ability,and reaction activity of the fillers.CGFS-F2 and CGFS-F3 can reduce the total amount of VOCs volatilized from PP resin by up to 63.1%and 67.6%respectively,while the commercially available deodorant has no deodorization effect on PP resin.Compared to commercially available deodorant,the spherical form of CGFS-F filler is less likely to damage the molecular chain of the resin matrix,has a more uniform dispersion in the matrix,is more active,and has better pore properties.3.In order to improve the application range of CGFS-F,we discussed the universality of CGFS-F3 in polypropylene(PP),high density polyethylene(HDPE),low density polyethylene(LDPE),and linear low density polyethylene(LLDPE).The research shows that CGFS-F3 has an excellent reinforcing effect on the four resins,and the reinforcing effect is much higher than that of 2500 mesh calcium carbonate and commercially available deodorant.When the filler content was 30 wt%,the average reinforcement effect of CGFS-F3 on tensile,flexural,and impact strength of PP,HDPE,LDPE,and LDPE was 46.7%,83.6%,and 211.9%higher than that of 2500 mesh calcium carbonate,respectively;meanwhile,it was 62.3%,79.3%,and 64.7%higher than that of commercially available deodorant,respectively.At the same time,the Turcsanyi model analysis shows that CGFS-F3 has the highest interfacial adhesion strength with the four kinds of resin and the most uniform dispersion in the four resin matrices compared with 2500 mesh heavy calcium and commercially available deodorant.4.CGFS-F3 has a different deodorization performance among the four resins.The deodorization effects of CGFS-F3 on PP,LDPE,and LLDPE materials are up to 69.6%,81.3%,and 91.1%,while the deodorization effects of commercially available deodorant in these three resins can only reach-21.9%,9.8%,and 54.0%.Both deodorants have no deodorization performance on HDPE resin,but commercially available deodorant will cause HDPE composites to volatilize more VOCs.The main reasons for the different deodorization performance of CGFS-F3 are as follows:the introduction of deodorants will break the internal molecular chains of the matrix,and the degree of damage to the matrix increases with the denseness of resin molecular chains,the denser the internal structure of the resin matrix,the more additional VOCs will be generated by the destruction of the molecular chains of the matrix by the deodorant particles,and the worse the deodorization effect in the early stage.Therefore,at the low deodorant content,the chain-breaking effect was greater than the adsorption effect,so the deodorization performance of the material was poor.As the deodorant increases,the adsorption effect is greater than the chain-breaking effect,so the deodorization performance of the material improves.5.The phase and thermal stability analysis of the composites showed that the addition of CGFS-F3 can effectively improve the thermal stability of the composites without changing the crystal structure of the four resins.In addition,the density of CGFS-F3-filled composites is lower than that of commercially available calcium carbonate and deodorant-filled composites,demonstrating that less material is consumed in the production of the same item,further reducing the cost of preparation.Therefore,combining the cost and performance of the material,the CGFS-F3 has significant application value in the field of resin deodorization and reinforcement.In summary,the research strategy of this paper is to use coal gasification fine slag,an environmental pollutant,to treat environmental pollutions so as to achieve the dual purpose of resource recovery and environmental protection.