Preparation Of Cellulose Acetate Microspheres And Adsorption Of Bromelain

In this paper,1-allyl-3-methylimidazolium chloride([Amim]Cl)was synthesized by one-step method,cellulose was extracted by acid-base method,and cellulose was modified by homogeneous method to obtain cellulose acetate.The cellulose acetate microspheres were prepared by reverse phase suspension method using cellulose acetate as raw material and 1-allyl-3-methylimidazolium chloride salt as the solvent to regenerate cellulose acetate.The effect of various factors on the adsorption process was studied by using the regenerated cellulose acetate microspheres as the adsorbent and bromelain as the adsorption model.The main conclusions are as follows:1.The regenerated cellulose acetate microspheres were prepared by reverse phase suspension method using cellulose acetate as raw material and 1-allyl-3-methylimidazolium chloride salt as the solvent.The effects of the mass fraction of cellulose acetate([Amim]Cl),the temperature of the system,the stirring speed and the amount of continuous phase on the particle size distribution of regenerated cellulose acetate microspheres were studied.Three factors were designed on the basis of single factor The results showed that the optimum preparation process of cellulose acetate microspheres was as follows: the mass fraction of cellulose acetate was 4%,the stirring speed was 650r/min and the reaction temperature was 80?.The order of factors affecting the particle size distribution range is: cellulose acetate mass fraction> stirring speed> reaction temperature.2.The regenerated cellulose acetate microspheres prepared under the optimized conditions were subjected to particle size analyzer,Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),field emission scanning electron microscopy(SEM)Cellulose acetate microspheres were characterized.The results showed that the crystalline form of regenerated cellulose acetate microspheres was changed from crystalline I to crystalline II and cellulose acetate microspheres were porous.3.The regenerated cellulose acetate microspheres prepared by reverse suspension method were used as adsorbents and bromelain as the adsorption model.The effects of PH value,initial concentration of bromelain,reaction temperature and adsorption time on the adsorption process were studied.The results showed that the adsorption capacity of the regenerated cellulose acetate microspheres to bromelain was 469.1mg/g when the adsorption time was 240 min,the shock temperature was 40?,the initial concentration of the solution was 1200mg/L and the p H value of the solution was 9.0.4.cording to the dynamic model parameters,the adsorption process of the regenerated cellulose acetate microspheres to bromelain is more consistent with the second-order kinetics model.The isothermal adsorption model parameter indicates that the adsorption of bromelain by regenerated cellulose acetate microspheres conforms to Langmuir isothermal adsorption model and belongs to monolayer adsorption.According to the thermodynamic parameters of ?G <0,it shows that the adsorption process is spontaneous;?S> 0,indicating that the adsorption process is endothermic reaction,the temperature is conducive to adsorption;?H> 0,and higher than 40 k J/mol,the experiment Of the ?H is 50.78 KJ.mol-1,the absolute value is more than 40 KJ.mol-1,indicating that the main force during the adsorption process is the chemical bond force,indicating that the chemical adsorption plays a major role.The kinetic results showed that the adsorption of Bromelain by regenerated cellulose acetate microspheres was in accordance with the Mckey secondary adsorption kinetics model.