Study On The Dissolution Process Behavior And High-value Utilization Of Solid And Liquid Components Of Cane Pith Hemicellulose In NaOH-H₂O₂-water System

The production of high value-added products from agricultural straw and other renewable resources has become a priority theme in the world.As a low-value waste product of sugar paper co-production industry,due to the features of rich cellulose and hemicellulose,bagasse pith can be used to prepare advanced functional materials relatively and realize its high-value utilization.However,the existing resource utilization technologies have some key technical bottlenecks,such as low resource utilization,high environmental load or high cost,which limit the large-scale application of follow-up functional materials.Therefore,under the premise of ensuring the efficient utilization of resources,the development of more economic and environmental protection of new technologies is an important measure to realize the large-scale utilization of bagasse pith waste,which is also highly consistent with the major strategic planning of�high-value utilization of agricultural and forestry biomass resources�in the field of light industry and agriculture and forestry and is of great significance to the Rural Revitalization Strategy being implemented in China.Based on this,this paper mainly uses Na OH-H₂O₂ aqueous solution to treat bagasse pith raw materials,so as to make hemicellulose dissolve efficiently,and then realize the functionalization of valuable substances in solid and liquid components respectively,so as to realize the nonwaste biomass refining of bagasse pith fiber raw materials.The specific research contents and main conclusions are as follows.Firstly,the hemicellulose extracted by Na OH-H₂O₂aqueous solution was quantitatively analyzed by alcohol precipitation gravimetric method.The results showed that the influence of by-products(lignin,ash,etc.)in the extraction process on the accuracy of the determination results could be ignored.The subsequent kinetic behavior analysis showed that the hydrodynamic diameter of alkali hydrated ions was just matched with the layer spacing of cellulose microfibers with the alkali concentration was?100 g/L;At this time,the extraction rate of hemicellulose reached the maximum.After analyzing the kinetics model of the dissolution process,the activation energy is 22.19 k J/mol,which indicates that the dissolution process of hemicellulose is mainly controlled by physical diffusion.Under the experimental conditions,the model can effectively predict the degree of hemicellulose dissolution in the process of extracting bagasse pith with normal pressure sodium hydroxide hydrogen peroxide.Second,the hemicellulose acrylamide hydrogel carrier(HEMI-g-AAMs)was prepared by oxidative reduction radical polymerization graft acrylamide onto the bagasse pith hemicellulose macromolecules.Then HEMI-g-AAMs loaded palladium nanoparticles(Pd/HEMI-g-AAMs)were used for acetylene hydrogenation experiments.Acetylene hydrogenation experiments show that the acetylene conversion and ethylene selectivity are 100%and 94.70%respectively at 100 ^oC and a space velocity of 70000h^-1.The characterization results indicate that the nitrogen-rich groups on these hydrogel carriers can effectively control the physicochemical properties of palladium nanoparticles and indirectly affect the catalytic activity of the catalysts.These results provide a reference for the application of alkali soluble hemicellulose in the preparation of catalytic materials.Finally,based on the carbon rich and porous properties of bagasse pith alkali extracting residue,it was pyrolyzed and activated into porous biochar(BPR-BC)and used to purify wastewater containing Cr(?).The results of adsorption experiments shown that the prepared biochar has an ultra-high specific surface area,the adsorption of Cr(?)is spontaneous and endothermic,and the maximum removal capacity of Cr(?)arrived 186.76 mg/g.Based on the concept of"making waste from waste",copper species were doped into the waste adsorbent to make it a Cu/Cr-based supported catalyst,which was used in biomass furfural hydrogenation experiment to realize the rational and resource disposal of waste adsorbent.All in all,this paper realized the efficient separation of hemicellulose and cellulose lignin residue from bagasse pith by using alkali extraction technology.Combined with the follow-up resource utilization means,it can further realize the large-scale disposal of bagasse pith and similar fiber materials under the concept of no waste biomass refining.