Preparation And Functionalization Of Magnetic Cellulose Diacetate Microspheres From Waste Cotton Fabrics

Cellulose acetate is an important cellulose derivative,and it has a wide range of industrial applications in medical treatment,textile,composite materials,and so on.Cellulose diacetate has hydroxyl groups in the molecular chain because of the degree of ester,which makes it grafting modified and functionalized.In this paper,cellulose diacetate was prepared from waste cotton fabrics.Magnetic cellulose diacetate microspheres(MCDM)were prepared by emulsification method and embedded with magnetic Fe₃O₄ nanoparticles.The magnetic cellulose diacetate microspheres were modified by introducing xanthate groups to obtain magnetic cellulose diacetate microspheres grafting xanthate groups(MCDMX),which were applied to Cu²⁺adsorption;and by grafting reaction,the magnetic cellulose diacetate microspheres modified by polyethyleneimine(MCDMP)were prepared and applied to the adsorption of Pb²⁺.In this paper,FTIR,XRD,elemental analysis,SEM,BET and other characterization methods were used to characterize MCDM,MCDMX and MCDMP microspheres.The specific results are as follows:SEM and bet tests show that the MCDM microspheres are porous inside and outside,and the pore size is uniform spherical;the specific surface area is 125.8 m²/g,which will be conducive to the adsorption of dyes and heavy metal ions.The magnetic response of MCDM microspheres is very good,which is beneficial to the separation of MCDM microspheres from liquid phase.XRD,FTIR and elemental analysis showed that the magnetic Fe₃O₄ nanoparticles were embedded and successfully modified by xanthate and polyethylenimine.The results of adsorption experiments show that,under the condition of pH 7,20mg/L of initial concentration of methylene blue,the adsorption effect of MCDM microspheres on methylene blue is the best,and its adsorption capacity reaches 18.2mg/g.Under the condition of pH 6,100 min of adsorption equilibrium time,100 mg/L of initial concentration of Cu²⁺,the adsorption ability of MCDMX microspheres on Cu²⁺is the best,and its adsorption capacity is 76.5 mg/g.Under the condition of pH 6,the initial concentration was 250 mg/L and the adsorption time was 160 min,the adsorption capacity of MCDMP microspheres for Pb²⁺reached 196.1 mg/g.The pseudo second order kinetic model and Langmuir isothermal adsorption model can well fit the adsorption process of methylene blue on MCDM microspheres,Cu²⁺on MCDMX microspheres and Pb²⁺on MCDMP microspheres,which are mainly characterized by monolayer adsorption and chemical adsorption,but the effect of internal diffusion process can not be ignored.The adsorption capacity of MCDM microspheres,MCDMP microspheres and MCDMX microspheres was still high after more than three times of recycling.