Research On The Adsorption Performance Of Sulfamic Acid Modified Coal-series Kaolin With CuFe₂O₄ Loaded For Congo Red

Congo red is an anionic diazo dye based on benzidine,which is widely used in the textile and rubber industries.Congo red dye wastewater has toxic effects on aquatic animal,plants and microorganisms.Coal-series kaolin is a mineral resource with rich reserves.Its main component,kaolinite,is a clay mineral formed by the interconnection of Al-O octahedron and Si-O tetrahedron structure unit layer.There are a lot of active sites on the surface of kaolinite,such as structural hydroxyl and surface free hydroxyl,and it has central cation exchange properties.Therefore,it is necessary to prepare it as an adsorption material to broaden its application range.This work took coal-series kaolin as the research object,and used calcination and sulfamic acid modification to treat it.The optimal temperature for calcination pretreatment was 400℃.The optimal conditions for the modified calcined coal-series kaolin with sulfamic acid were as follows:sulfamic acid concentration was 0.5 mol/L,liquid-solid ratio was 25 m L/g,modification time was 120 min,and modification temperature was 55℃.The analysis results of specific surface area and pore diameter（BET）,environmental scanning electron microscopy（SEM-EDS）,X-ray diffraction（XRD）,and fourier transform infrared spectroscopy（FT-IR）showed that calcination and sulfamic acid modification increased the specific surface area and pore volume of coal-series kaolin.The specific surface area and total pore volume of coal-series kaolin before modification were 6.31 m²/g and 0.013 cm³/g,respectively.After modification,the specific surface area and total pore volume of coal-series kaolin were 78.36 m²/g and 0.213 cm³/g,respectively.The specific surface area and total pore volume increased by 11.42 times and 15.38 times,respectively.The modified calcined coal series kaolin was mixed with CuFe₂O₄ at a mass ratio of 1.6,and the composite adsorption materials with good magnetism（saturation magnetization of 9.17 emu/g）were prepared by the sol-gel method.The optimal conditions for the adsorption of Congo red by composite adsorption materials were determined,that is,p H value of the solution was 5,dosage was 1.5 g/L,adsorption temperature was 40℃,and adsorption time was 60 min.The adsorption quantity and removal rate of Congo red by the composite adsorption material were 59.11 mg/g and88.66%,respectively.The results of adsorption isotherm,adsorption kinetics/thermodynamics,FT-IR and X-ray photoelectron spectroscopy（XPS）showed that the adsorption of Congo red on the composite adsorption materials was due to electrostatic attraction and hydrogen bonding.The composite adsorption materials have good cyclic regeneration performance.The optimal conditions for calcination desorption were calcination time of 40 min,calcination temperature of 350℃.The optimal conditions for Na OH desorption were Na OH concentration of 0.3 mol/L,solid liquid-ratio of 1.25 g/L,desorption time of 90min,and desorption temperature of 45℃.The appropriate cycle times for calcination and Na OH desorption were 3 and 4,respectively.Under suitable cyclic desorption times,the desorption rate of Congo red on composite adsorption materials were 86.65%and89.68%,respectively,and the removal rate of Congo red on composite adsorption materials were 80.25%and 83.05%,respectively.This work achieved the preparation of composite adsorption materials using coal-series kaolin as raw material,which promoted the efficient utilization of coal-series kaolin and provided a new approach for the treatment of Congo red dye wastewater.There are 49 figures,18 tables and 107 references in this thesis.