Study On Adsorption Of Dyes In Wastewater By Carboxymethyl Cellulose Composite Film

The adsorption method is one of the most commonly used methods for the treatment of dye wastewater.The key is to develop green,environmentally friendly,degradable adsorbents with excellent adsorption properties.The composite film is favored by researchers because of its advantages such as high adsorption efficiency,degradability and easy recycling.In this paper,a new type of composite film based on sodium carboxymethyl cellulose(CMC)was prepared,and the influence of CMC and its performance parameters on the hydrophilic and mechanical properties of the composite film was studied.The structure of the film was characterized.On this basis,the adsorption properties of the composite film for methylene blue dye(MB)were studied.The research is divided into the following aspects:(1)Preparation of CMC-MMT-PVA and CMC-MMT with carboxymethylcellulose sodium(CMC),montmorillonite(MMT)polyethylene glycol(PEG)and polyvinyl alcohol(PVA)as basic components-PEG composite film.Determine the optimal dosage of each component of the composite film:(1)Carboxymethylcellulose(CMC),montmorillonite(MMT)and polyvinyl alcohol(PVA)were used as the basic components to prepare CMC-MMT-PVA composite film to study the effect of CMC dosage and performance parameters on the performance of composite film.The results show that the swelling rate of CMC-MMT-PVA composite film increases first and then decreases with the increase of CMC mass fraction;the contact angle decreases with the increase of CMC mass fraction.It indicates that the increase of CMC makes the hydrophilic groups in the composite film increase,and the composite film has greater hydrophilicity.The tensile strength of CMC-MMT-PVA composite film increases with the mass fraction of CMC,and then tends to increase first and then gradually decrease.The elongation at break decreases with the increase of the mass fraction of CMC.The degree of substitution of CMC has little effect on the swelling rate and mechanical properties of CMC-MMT-PVA composite film,but CMC viscosity has a greater effect on it.As the viscosity of CMC increases,the swelling rate increases first and then decreases;the greater the viscosity of CMC,the better the mechanical properties of the prepared composite film.The greater the degree of substitution of CMC,the smaller the contact angle of the composite film,and the greater the viscosity of CMC,the greater the contact angle of the composite film.When the CMC substitution degree is 0.95,the viscosity is 1020MPa?s,and the dosage is 50%,the prepared composite film has the best performance.The XRD,SEM and FTIR characterization methods prove that CMC-MMT-PVA has been successfully cross-linked to form a uniform composite film under the cross-linking of glutaraldehyde.(2)Carboxymethylcellulose(CMC),montmorillonite(MMT)and polyethylene glycol(PEG)were used as basic components to prepare CMC-MMT-PEG composite film,and studied the influence of the amount of CMC and performance parameters on the performance of the composite film.The results show that the swelling rate of the CMC-MMT-PEG composite film increases first and then decreases as the mass fraction of CMC increases.The contact angle becomes smaller as the CMC mass fraction increases.The tensile strength and elongation at break of CMC-MMT-PEG composite film decrease with the increase of CMC mass fraction.The degree of substitution of CMC has little effect on the swelling rate and mechanical properties of CMC-MMT-PEG composite film,but CMC viscosity has a greater effect on it.As the viscosity of CMC increases,the swelling rate increases first and then decreases.The greater the viscosity of CMC,the better the mechanical properties of the prepared composite film.The greater the degree of substitution of CMC,the smaller the contact angle of the composite film,and the greater the viscosity of CMC,the greater the contact angle of the composite film.When the CMC substitution degree is 0.95,the viscosity is 1020MPa?s,and the mass fraction is 65%,the prepared CMC-MMT-PEG composite film has the best performance.XRD,SEM and FTIR characterization methods prove that CMC-MMT-PEG has been successfully cross-linked to form a uniform composite film under the cross-linking of glutaraldehyde.The thermal stability of CMC-MMT-PEG composite film decreased with the increase of CMC dosage through TG thermogravimetric analysis.(3)The adsorption of methylene blue dye by CMC-MMT-PVA composite film showed that: when the CMC mass fraction in the film is 50%,the CMC-MMT-PVA composite film has the best adsorption effect on MB,and the maximum adsorption amount of MB is 9.98mg/g;its adsorption conditions are adsorption temperature 30?,pH 5,the adsorption time is 1h,and the initial concentration of MB is 200mg/L.(4)The adsorption of methylene blue dye by CMC-MMT-PEG composite film showed that: when the mass fraction of CMC is 65%,the CMC-MMT-PEG composite film has the best adsorption effect on MB,and the maximum adsorption amount of MB is 26.06mg/g;the adsorption conditions are adsorption temperature 30?,pH 3,the adsorption time is 1.5h,and the initial concentration of MB is 400mg/L.(5)Through the study of adsorption thermodynamics and adsorption kinetics,the results show that: The adsorption of MB by the two composite films conforms to the quasi-second-order kinetic model,and the adsorption isotherm conforms to the Langmuir model which belongs to the monolayer adsorption.By comprehensively comparing the adsorption effect of the two films on MB,it can be seen that: The adsorption effect of CMC-MMT-PEG composite film on MB is better than that of CMC-MMT-PVA film,the maximum adsorption capacity of the former is 26.06mg/g,and the latter is 9.98mg/g.