| China's bagasse reserves are abundant and it is a very promising bioethanolrefining raw material.In this study,the physical and chemical characteristics of bagasse after pretreatment with dilute acid?DA?,sulfite?SPORL?and cellulase?SPCTec2?were compared,and the adsorption/desorption behaviors of three pretreated bagasse and cellulase enzymes were systematically studied.Finally,from the perspective of pretreatment bagasse hole characteristics,the reason for the difference between cellulase and baga sse adsorption/desorption was analyzed.The main contents of this study are as follows:1.The physicochemical properties of three types of pretreated bagasse.Analyzed the three kinds of bagasse physical and chemical properties,the results show that:DA,SPORL and SPCTec2 three kinds of bagasse cellulose content were 55.05%,54.36%,40.57%,hemicellulose content were:10.51%,11.17%,1.6%T he bagasse lignin content of DA?32.06%?was slightly higher than that of SPORL?28.60%?,and the lignin content of SPCTec2 bagasse?57.47%?was the highest.The crystallinity of DA,SPORL,and SPCTec2 bagasse was 61.72%,63.84%,and 73.84%,respectively,by XRD pattern analysis.The results of FTIR characterization showed that the C=O structure of the three pretreated bagasse xylans was broken,and the C=O stretching vibration peaks of the SPCTec2 pretreated bagasse almost disappeared.T he SEM observation showed that compared with the untreated bagasse,the pretreated bagasse fibers were partially peeled,the fiber skele ton was exposed,and small holes appeared on the bagasse surface.2.Adsorption properties of cellulase by three pretreated bagasses.T hrough adsorption experiments,it was found that at p H 5.3,the maximum adsorption of DA bagasse and SPCTec2 bagasse at t he same temperature was greater than that of SPORL pretreatment bagasse.The adsorption equilibrium constant K and the binding strength T of the bagasse pretreated by SPORL method are higher.Through adsorption kinetics experiments,it was found that the a dsorption of cellulase and pretreated bagasse could reach the maximum adsorption value in about 20min.It was also found that the time for adsorption of fibrinase and three kinds of pretreated bagasse reached equilibrium at 50°C was less than 10min.At 25°C,the equilibrium time for adsorption reached about10 minutes.At the temperature of 4°C,the three kinds of pretreated bagasse reached equilibrium after 20 min.3.The desorption properties of cellulase by three pretreated bagasses.By desorption experiments,it was found that the desorption amount of the three pretreated bagasses increased by increasing the p H and the temperature of desorption.The desorption rates of different bagasses were studied:The desorption rate of cellulase on SPORL bagasse?9.21%?was greater than that on DA?8.21%?and SPCTec2?6.32%?bagasse.Desorption kinetics experiments showed that the desorption of cellulase quickly reached equilibrium within 20 min.4.bagasse hole characteristics.Exploring the relationship between t he properties of pretreated bagasse pores and adsorption/desorption.The results show that SPCTec2pretreatment bagasse has a larger pore volume(0.025 cm3·g-1)and a specific surface area(2.62 m2·g-1).The holes distributed on SPORL bagasse and DA bagass e are mainly in the pore size range of 3-26 nm.In the range of mesopores,SPCTec2 bagasse contains not only mesopores,but also a small amount of macropores?pore diameter?50nm?.It is known from the water retention test that the water retention value o f the bagasse treated by the SPCTec2 method is higher than that of the DA and SPORL pretreated bagasse. |
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