Preparation Of Camellia Oleifera Seed Shell Carbon Microspheres By Stepwise Hydrothermal Method And Research On Sphere Formation Mechanism

Biomass,as the only renewable carbon energy source on earth,is considered to be an important new energy source that can replace traditional fossil fuels.Camellia husk,as one of the by-products of camellia oleifera processing tea oil,is basically discarded or incinerated.If the structure of the camellia husk can be understood correctly,it will be made of carbon microspheres as raw materials,and the camellia husk is used in many ways.Increasing the added value of the camellia industry is of great significance,and it can also achieve sustainable economic and ecological development.At present,there are still problems that the structure of the camellia husk is not clear,the variability of the prepared carbon microspheres cannot be eliminated,and the mechanism of the sphere formation is not clear,etc.,which greatly limits the application of the camellia husk carbon microspheres.In view of the above problems,this paper studies the structure of camellia husk and explores a method of preparing single-dispersed,non-impurity,and homogeneous carbon microspheres from camellia husk as raw material,which can be replaced with camellia husk hydrothermal carbon The formation mechanism of microspheres is decomposed in detail.The main research contents are as follows:(1)In view of the problem of the unclear structure of camellia husk,the two components of camellia husk(camellia oleifera shell and camellia seed hull)were subjected to SEM,elemental analysis and composition analysis,and the results of the camellia husk and camellia seed hull were analyzed.The results showed that the surface of the camellia camellia showed a flaky structure,and the flaky surface had uneven orientation,while the camellia seed husk powder was mostly irregular and loose bulk structure.The constituent elements of Camellia oleifera shell and Camellia oleifera seed shell are C,H and O.The main components are cellulose,hemicellulose and lignin.The Camellia oleifera seed shell is separated from the Camellia oleifera shell,and the lignin in it fills the spherical structure.Therefore,the Camellia oleifera seed shell is easier to produce good-looking carbon microspheres.(2)Aiming at the problem that the uncertainty of the carbon microspheres obtained from the preparation of Camellia oleifera shells cannot be eliminated,the Camellia oleifera seed shells are used as the carbon source,and the stepped hydrothermal method is used to prepare the Camellia oleifera seed shell precipitated carbon microspheres.That is,after the low temperature hydrothermal of the camellia seed shell,the non-balled part is removed,and the obtained residue is subjected to a hydrothermal reaction again to obtain the precipitated carbon microspheres of the camellia seed shell.The results of secondary hydrothermal additives,the amount of additives,hydrothermal time and filling degree show that when the secondary hydrothermal temperature is 230 ℃,the reaction time is 8 h,the resorcinol: residue amount is 1: 5.The degree of filling is 54%,the resulting carbon microspheres are monodisperse,expected to be uniform and almost free of impurities.(3)Aiming at the problem of the unclear formation mechanism of the precipitated carbon microspheres in camellia seed shells,the carbon material is obtained by hydrothermally heating the camellia seed shells and the cellulose,hemicellulose and lignin extracted from the camellia seed shells and combining their liquids The results show that during the low-temperature hydrothermal process,most of the hemicellulose is decomposed,and the resulting residue is mainly produced by undecomposed cellulose and lignin.get.In the process of hydrothermal carbonization,cellulose generates furfural and organic small molecular acid,and hemicellulose generates cyclopentenone and organic small molecular acid.During the formation of carbon microspheres,furfural and cyclopentenone react with pyrogallol and monophenol under the action of small organic acids.These macromolecular polymers gradually grow on the surface of the inner core,And finally form carbon microspheres with abundant oxygen-containing functional groups on the surface.(4)For the waste of resources caused by the conversion of most of the supernatant produced after low temperature crushing to hemicellulose.If the oil-seed camellia husk supernatant can be hydrothermally carbonized to prepare carbon microspheres,it is high-quality oil-seed camellia husk supernatant as the carbon source,and it has no impurities and has uniform carbon at 230 ℃ for 8 h.Microspheres.The obtained carbon microspheres are monodisperse systems with a volume distribution between 0.8-1.1 μm.The formation process of the carbon microspheres in the supernatant of camellia seed husk conforms to the Lamer growth theory.The spheroidal components are hemicellulose growth products-furan wood.These sugars undergo dehydration-polymerization-aromatization process to form a surface Carbon microspheres with hetero-oxygen-containing functional groups.