| The main problem of cationic dyes is that the wastewater discharged after use is difficult to handle,which not only causes harm to the environment,but also causes waste of dyes.At present,the main method to solve the problem at home and abroad is still terminal management,and there is no source-control technology.In this paper,a sodium alginate/polyvinyl alcohol(SA/PVA)composite membrane was prepared by casting method and electrospinning technology,and the adsorption of cationic dyes was studied.The calcium chloride anhydrous ethanol solution was used to compound SA/PVA.Membrane modification,adsorption of cationic dyes by modified membrane,adsorption capacity and dye removal rate as evaluation indicators,study of SA/PVA composite membrane adsorption of basic magenta dye,methylene blue dye,methyl green dye.Single factor experiment and orthogonal experiment were used to study the adsorption performance of SA/PVA composite membrane on cationic dyes,which provided a theoretical basis for the treatment of cationic dye wastewater by adsorption.The main research work of the thesis is as follows:(1)SA/PVA composite film was prepared by electrospinning method and casting film method respectively.The microstructure and diameter of SA/PVA nanofiber membrane were analyzed by scanning electron microscope.Infrared spectrum analyzer and X-ray photoelectron energy were used.The spectrometer and other testing methods were used to analyze the material changes of the SA/PVA nanofiber membrane.The best spinning process of the SA/PVA membrane was as follows: the volume ratio of SA:PVA was 1:9,and the spinning voltage was 16 kV.The spinning distance was 15 cm and the spinning speed was 1.2 mL/h.(2)Adsorption of basic fuchsin dye by SA/PVA,SA/PVA/PET composite nanofiber membrane prepared by electrospinning method,the removal rate and adsorption amount of basic fuchsin dye in solution by fiber membrane.In order to evaluate the indicators,the optimal adsorption conditions were determined by single factor experiments and orthogonal experiments.After adsorption,the adsorption effect of SA/PVA/PET composite nanofiber membrane on basic fuchsin dye was better.(3)The SA/PVA composite membrane was prepared by casting method.The removal rate of dyes in the solution was evaluated.The single factor experiment and response surface experiment were used to study the SA/PVA film on the basic fuchsin dye,methylene blue dye,and A.The adsorption performance of the green dye was optimized,and the adsorption conditions were optimized.It was found by comparison that the adsorption effect of the SA/PVA film on the methylene blue dye was better.(4)The adsorption behavior of the dye was analyzed by the kinetic equation and the isothermal adsorption model.It was found that the Freundlich isotherm adsorption model can better evaluate the adsorption behavior of the SA/PVA composite nanofiber membrane on the basic fuchsin dye.The adsorption of the methylene blue dye by the prepared SA/PVA film is more consistent with the Langmuir isotherm adsorption model.The adsorption process of the dye prepared by the two methods conforms to the quasi-second-order kinetic equation,which is affected and controlled by the chemical adsorption mechanism. |
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