| Due to the characteristics of high gasification intensity and adaptability of coal type,gas flow bed coal gasification technology plays a leading role in advanced coal clean and efficient utilization technologies such as indirect coal liquefaction,but it has consequently caused a large amount of emission of coal gasification fine slag(CGFS).CGFS is a residue separated from the syngas purification process,mainly characterised by high carbon content and high silica and aluminium content in ash,which is a potential source of carbon and silica and aluminium for the preparation of activated carbon and zeolite.The activated carbon and zeolite composite materials are prepared by activation and hydrothermal crystallization of the gasification fine slag as raw materials,which can be used for the adsorption and deep purification of hard-to-degrade organic matter in industrial wastewater,to achieve the purpose of "turning waste into treasure and treating waste with waste".Based on the above objectives,this study investigates the physicochemical properties of CGFS,uses the characteristics of CGFS,which is rich in silicon,aluminium and carbon,and prepares functional materials by choosing a reasonable synthesis process,and applies them to the treatment of phenol-containing wastewater and dye wastewater,which achieves the purpose of "treating waste with waste" and provides a new theoretical basis for the resource utilization of CGFS.The main research results are as follows:(1)The main components of CGFS are residual carbon and amorphous aluminosilicate,with a residual carbon content of 30%and an ash content of 59.04%and 16.95%of silica-aluminium respectively,which makes it a good raw material for the preparation of functional materials.The Y-type zeolite/activated carbon composites were prepared by acid leaching,alkali activation and hydrothermal method.The YC sample had a large specific surface area of 439.68 m2/g,a pore volume of 0.35 cm3/g and a pore size of 1.60 nm under the optimum conditions of 36 h of crystallisation at 100℃.The maximum adsorption of phenol was 47.62 mg/g under the optimum adsorption conditions of pH=7,0.1 g adsorbent addition,100 mg/L initial concentration of phenol solution and 120 min adsorption time.(2)Carbon and ash separation from CGFS can be achieved by NaOH alkaline desilication.SBA-15 with a highly ordered pore structure was prepared using the CGFS alkali leachate as the silica source,and the filtrate was used to prepare X-type zeolite/activated carbon composite.The specific surface areas of the two samples were 793.42 m2/g and 477.75 m2/g respectively.The pore channel modulation of SBA-15 and XC was carried out by adding TMB swelling agent and CO2 pre-activation,respectively,and the surface ammonia functionalisation of the expanded samples was carried out to improve the equilibrium rate and adsorption capacity.Under optimal adsorption conditions,the maximum adsorption of rhodamine B dye was 147.93 mg/g and 157.98 mg/g for the two materials,respectively.Electrostatic attraction and hydrogen bonding play an important role in the adsorption process.(3)Preparation of MCM-41 with highly ordered pore structure by microwave synthesis using CGFS alkali leach solution as a silica source.Under the optimum synthesis conditions,the sample had a specific surface area of 862.03 m2/g,a pore volume of 0.59 cm3/g and a pore size of 3.02 nm.The MCM-41 was functionally modified by surface grafting of amino groups to obtain NH2-MCM-41 sample which still had a regular pore structure.It showed selective adsorption for both the cationic dye methylene blue and the anionic dye congo red,with maximum adsorption amounts of 292.40 mg/g and 354.61 mg/g,respectively,electrostatic attraction,hydrogen bonding and π-π interactions play an important role in the adsorption process. |
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