Preparation And Application Of Clarifying Agent For Chitosan Phosphate In Sugar Manufacture

White sugar is a national strategic material,Guangxi sugar production accounts for about 60%of the total output,the sugar industry is a pillar industry in Guangxi.More than 90%of the country’s sugar cane sugar can be used to clarify the process,but this method is not enough to study the new clarifier and process to improve the quality of white sugar and improve the international competitiveness of China’s sugar is essential.Chitosan(CTS)has good adsorption,film-forming,fiber-forming,hygroscopicity and biocompatibility.It is widely used in food,medicine,chemical and other fields,and has become a hotspot.In this study,chitosan was phosphorylated to prepare chitosan phosphate(PCTS),improve water solubility,and apply it to clarification of sugarcane mixed juice to explore the sulfur-free clarification process.This topic contains the following research:1.The basic physical and chemical properties of chitosan were measured,including deacetylation and viscosity average molecular weight.The desmethylation degree of chitosan was 78%,the viscosity average molecular weight M was 6.19×105,and the crude product of chitosan phosphate was prepared.The effects of chitosan and chitosan phosphate on the clarification of sugarcane mixed juice were discussed.Compared with the traditional method of clarification of sulfurous acid,it was found that the clarification effect of chitosan was higher than that of subfamily,but the decolorization rate and purity difference were improved,but the content of calcium salt was higher,which was detrimental to subsequent evaporation and boiling.After treatment with chitosan phosphate,the purity and decolorization rate of the juice were improved,and the content of pure calcium was lower than that of traditional sulfurous acid.2.The chitosan phosphate was prepared by phosphorylation of chitosan,and the optimum conditions for the preparation of chitosan phosphate were explored by decolorization rate and purity difference.The effects of m(chitosan),m(formaldehyde),m(chitosan):m(phosphoric acid),microwave power and microwave time on the clarification of chitosan phosphate were investigated by orthogonal test.The optimum conditions for the preparation of chitosan phosphate were as follows:m(CH2O):m(chitosan)= 1:1,m(H3PO4):m(chitosan)= 3.2:Microwave power 260W,microwave time 9min,in this condition,the decolorization rate of sugarcane juice up to 70%,purity increased by 2.5%.3.(1)The properties of chitosan phosphate obtained under the optimum preparation conditions were determined.The degree of substitution of chitosan phosphate was determined by acid-base titration.(2)The surface microcosmic morphology of chitosan phosphate was observed by electron scanning electron microscopy(SEM).It was found that the microstructure of chitosan changed greatly.Unmodified chitosan for the irregular shape,rough surface,there are more folds,showing concave and convex.After the modified chitosan phosphate is more regular spherical,the same magnification,you can see,a single chitosan phosphate particles smaller,and the size of different,the surface has wrinkled bulge.(3)FI-TR observed the characteristic peaks of chitosan phosphate,and identified the structure of chitosan phosphate.The infrared spectrum of chitosan phosphate was larger than that of chitosan,and it was confirmed that the phosphate group was successfully introduced into the chitosan molecule by comparison.(4)The mechanism of chitosan phosphate in the mixture of chitosan phosphate was studied.The adsorption characteristics of chitosan phosphate in the mixed juice were studied.During the experiment,the pH of the adjusted sugarcane juice was determined to be 7.0.In the experiment of adsorption equilibrium,it was found that the adsorption equilibrium time of phenolic compounds in chitosan phosphate was 60 min.In the study of kinetics,it was found that chitosan phosphate adsorbed the kinetics of phenolic compounds in sugarcane juice more in line with the second-order kinetics model.In the isothermal adsorption experiment,it was confirmed that the isothermal adsorption model of chitosan phosphate in the juice was more consistent with the Freundlich isothermal adsorption model.The thermodynamic analysis showed that AGO was less than zero,indicating that the chitosan phosphate adsorbed the juice Phenolic substances spontaneously carried out;△H0 is greater than zero,indicating that chitosan phosphate adsorption of phenolics in the juice is an endothermic reaction,when the temperature increases,conducive to the adsorption of phenolic materials.△S0 greater than zero indicates that chitosan phosphate increases the degree of chaos in the solid-liquid interface during the adsorption process of phenolic compounds in sugarcane juice.4.Chitosan phosphate was used to clarify the mixed juice to establish the best clarification process.The results showed that the effective P2O5 content,the pre-ash pH,the primary heating temperature,the amount of chitosan phosphate and the secondary heating temperature were determined by single factor experiment and response surface test with the difference of purity,decolorization rate,settling rate and clear calcium content.,Flocculant dosage and other process parameters.The final treatment parameters of chitosan phosphate were as follows:the effective P2O5 content was 284 mg/L,the first heating temperature was 50 ℃,the pre-gray pH was 7.0,the dosage of chitosanphosphate was 125 mg/L,the second heating temperature is 96 ℃,PAM dosage is 4.8 mg/L.