Study On The Transformation Process Of Biomass-based Carbon Material Under Acid-catalyzed

With the development of the industry and economy, people’s living standardshave been improved. But at the same time, energy shortages and environmentalpollution had become worldwide problems. Recently, much attention has beenfocused on utilization of renewable energy, sustainable development and environmentfriendly, which had become an important development strategy in many countries.Now, there was a continued growth trend of production biomass fuels and functionalinorganic nanomaterials from nature biomass, due to the shortage of crude oil andenvironmental problems. Biomass materials have the following advantages: richresources, extensive sources, renewable and biodegradable. And many biomasseshave been widely used in the fields of synthetic plastics, fibers, functional materials,composite materials. Biomasses could be converted into biofuels and functionalcarbon materials by biological and thermal conversion, however, thermal conversionmainly included hydrothermal treatment and pyrolysis. In the field of application onbiomass, the liquid product of the biomass fuel and synthesis gas had caused muchattention, but the by-products of pyrolysis process were not got reasonable use,resulting the waste of biomass resources.So far, preparation of functional nano-carbon material from waste biomassmainly applied hydrothermal treatment (about200℃) method. As the limitation ofexperimental apparatus and reaction conditions, it was very difficult to achieve theindustrial production of hydrothermal carbon and it also caused large obstacles todevelopment and application of biomass. Rice husk and corn cubs were two kinds of common biomass, both of them contained large amounts of cellulose, hemicelluloseand lignin. Transformation of carbon in biomass to valuable carbon material hasattracted considerable interest of researchers.Based on the above research background, this study is divided into the followingparts:(Ⅰ) We prepared colloidal carbon material from pentose (xylose), hexoses(glucose and fructose) under low temperature and the catalysis of sulfuric acid, thenwe investigated the impact of reaction temperature, sulfuric acid concentration,reaction time and other factors on the yield and microstructure of final production, atthe same time, the best experimental conditions was got. In addition, throughelemental analysis and spectroscopic studies, it was found that hydroxyl, carbonyl,carboxyl, ether groups and other functional groups were located on the surface of thecarbon product derived from monosaccharide. And the different mechanisms ofsynthetic colloidal carbon from pentoses and hexoses were discussed in detail.(Ⅱ) According to the above study, the colloidal carbon products were preparedfrom monosaccharide with phenolic compounds (phenol, resorcinol, andphloroglucinol). The great changes of morphology and microstructure in sample havebeen observed by XRD spectrum and TEM picture. It was also found that the yield ofproducts was related to the number of hydroxyl groups in the phenolic compounds. Areasonable carbonation mechanism was proposed by series of the analysis results.(Ⅲ) Firstly，cellulose, hemicellulose contained in rice husk and corncob weredecomposed into pentose and hexose by sulfuric acid hydrolysis. Then the colloidalcarbon samples were synthesized by hyrothermal treatment of pentose and hexosesolution (containing sulfuric acid) with phenolic compounds. Hereafter, porous carbonwas prepared from colloidal carbon activation by H3PO4in500℃. Finally, theperformance of electrical double layer capacitors with porous carbon was detected bycurrent charge-discharge and cyclic voltammetry.The paper exhaustively described a new method to synthesize high yield of colloidal carbon derived from monosaccharide and nature biomass with phenoliccompounds. Through systematic experiment and detailed characterization methods,we proposed the possible mechanism to the formation of carbon product by sulfuricacid catalyst. From environmental point of view, this synthesis method achieved thenegative growth of carbon dioxide in the atmosphere. However, making full use ofrice husk and corn cob could solve the natural biomass waste and environmentalproblems and at the same time, create greater economic value.