Study On Preparation Of Aerogel From Coal/Heavy Oil Hydrogenation Co-refining Residue

Coal/heavy oil hydrogenation co-refining technology is an important way to rationally use coal resources.Due to the complex composition of the raw materials,a certain amount of residue will be produced after the reaction.The resource utilization of this part of the residue is of great significance to the development of the coal/heavy oil hydrogenation co-refining process.In this paper,the coal/heavy oil hydrogenation co-refining residue is used as the research object to explore the feasibility of preparing aerogels through the combined method of carbonization-high temperature graphitization-oxidation-hydrothermal synthesis.First,the effects of carbonization and graphitization conditions on the degree and structure of graphitization of the residue and its toluene soluble and toluene insoluble matter were investigated,and graphitized carbon was obtained.Then use graphitized carbon as raw material to prepare graphene oxide through an improved Hummers method.The feasibility of the direct hydrothermal synthesis of graphene oxide to prepare carbon aerogels and the hydrothermal synthesis of modified halloysite and graphene oxide composite aerogels are discussed.Finally,the adsorption performance of the aerogel product was evaluated by the aerogel adsorption experiment on the dye in water.Studies have shown that the optimal carbonization conditions for the coal/heavy oil hydrogenation co-refining residue and its toluene solubles and toluene insolubles are the carbonization temperature of 800℃and the carbonization time of 1h.The carbonized products of the three raw materials were subjected to high-temperature graphitization treatment at 2500°C for 3 hours,and the graphitized carbon product of toluene soluble material had the highest degree of graphitization（82.56%）.With the increase of graphitization temperature,the degree of graphitization shows a gradual increase trend.In the process of preparing graphene oxide by oxidation of graphitized carbon,the degree of oxidation of graphene oxide can be increased by extending the reaction time in the low-temperature reaction stage（5°C）and the medium-temperature reaction stage（35°C）.The optimal reaction time for both stages is 1.5h.The carbon aerogel was directly prepared from graphene oxide under the conditions of hydrothermal synthesis at 95°C for 5 hours,and the composite aerogel could be prepared by adding modified halloysite to graphene oxide under the same conditions.Under the conditions of 30°C,p H 7,and initial solution concentration of 50mg·L^-1,carbon aerogel and composite aerogel were used to perform adsorption experiments on methyl orange,methylene blue and malachite green,and carbon aerogel and composite aerogel Glue has the largest adsorption capacity for malachite green,and the adsorption capacity of composite aerogel is higher than that of carbon aerogel.When the composite aerogel adsorbs malachite green,the p H value of the solution increases,and the adsorption capacity first increases and then slowly decreases;with the increase of the adsorption temperature,the adsorption capacity increases.Under the conditions of 40°C,p H 8,and initial solution concentration of 50mg·L^-1,the adsorption capacity increases rapidly within0～200min,and then with the passage of time,the rate of increase of the adsorption capacity gradually slows down.After 5 adsorption-desorption cycles,the composite aerogel can still maintain an adsorption efficiency of more than 60%.