| In1935, Solidago Canadensis was introduced into our country (Shanghai, Nanjing) as garden plants. After a long period of latent, in the late1980s, it spreaded in more than10coastal provinces and cities. In2005, the distribution area in Jiangsu, Zhejiang and Shanghai got to16667hm2,11191hm2and7788hm2, respectively. Because of its wide distribution, strong ecological destructive, disaster govermance, it comes to be a serious threat to agricultural production, afforestation and ecological environment in our country. In this paper Solidago Canadensis was used as the raw material to extract α-cellulose, lignin and hemicellulose (pentose solution). Then they were used to prepare the industrial raw materials and got the microcrystalline cellulose, thin Layer Chromatography, levulinic acid, sand stabilization material, modified formic acid lignin, furfural. Characterizations, performance testings, wastewater treatment of products were studied at the same time. It was an effective way to control and manage this invasion plant when getting the products. The main contents of this study include several parts as follows:(1) The formic acid/hydrochloric acid pretreatment was used to separate the wood fiber components of the Solidago Canadensis. The a-cellulose, lignin and hemicellulose were extracted. The results showed that:when the solid-liquid ratio (g/v) of Solidago Canadensis and formic acid was1:12, the mass fraction of the formic acid was88%, the hydrolysis temperature was85℃, the reaction time was2.5h, with the37%hydrochloric acid as the catalyst, and we got the optimal conditions to separate the three wood fiber conponents, the recovery rate of a-cellulose, hemicellulose and lignin were86.09%,80.36%and62.78%, respectively.(2) Diluted sulfuric acid and hydrochloric acid were used to prepare microcrystalline cellulose with a-cellulose under100℃within120min and60min. The content of the microcrystalline cellulose samples were89.2%and91.8%, the average particle sizes of the samples were8.3μm and9.9μm, the degree of the crystallinity were84.03%and81.12%, and the grain sizes were15.23nm and14.03nm. The orthogonal test was carried out with the mixed acid. The different properties and requirements (the content, crystallinity, swelling volume ratio, adsorption of Cr6+) were studied in the mixed acid process. We got the optimal preparation conditions respectively, they were:①16%H2SO4+6%HCl,108℃reaction temperature,120min reaction time,1:20ratio of solid to liquid;②6%HCl,84℃reaction temperature,45min reaction time,1:10ratio of solid to liquid;③6%H2SO4+6%HCl,108℃reaction temperature,60min reaction time,1:20ratio of solid to liquid;④6%H2SO4+6%HCl,92℃reaction temperature,90min reaction time,1:10ratio of solid to liquid. The thin layer chromatography was prepared with the self-made microcrystalline cellulose, which separated the glucose and xylose successfully, the Rf values were0.5212and0.6409, respectively.(3) Levulinic acid was prepared by the reaction of sulfuric acid and a-cellulose in the high temperature and pressure conditions. The effects of technological conditions such as reaction time, temperature, acid concentration and ratio of solid to liquid on the yield of levulinic acid and reducing sugar are investigated. Gas chromatography was used to analysis the yield of levulinic acid. The result shows that, the optimal reaction conditions were:reaction temperature230℃, reaction time50min, solid-liquid ratio1:20, acid concentration6%and the yield of levulinic acid was high as27.62%. When the reaction was ended, the reducing sugar was almost degraded with1.02%remained. The byproduct from the process of the levulinic acid preparation was used with the graft composite modifiled material to get the sand stabilization material, the water retention rate of the sand stabilization material was tested at room temperature, and the result was78.26%after48h. It was then used to simulate the growth of the plants in desert conditions, the plant roots grew in a good condition. And the carbon emission was effectively reduced.(4) Formic acid lignin was modified by grafting and oxidation. Two modified materials were characterized with infrared and scanning electron microscopy and studied in methylene blue dye waste water and Cr (VI) heavy metal wastewater treatment. For graft composite modification material, in4h at room temperature, pH7, the adsorption capacity of methylene blue with the initial concentration of50mg/L was10.17mg/g, the removal rate was90.94%; in4h at room temperature, pH6, the adsorption capacity of Cr (VI) with the initial concentration of50mg/L was1.78mg/g, the removal rate was44.74%. For oxidative modification material, in12h at room temperature, pH10, the adsorption capacity of methylene blue with the initial concentration of50mg/L was5.42mg/g, the removal rate was81.93%; in6h at room temperature, pH6, the adsorption capacity of Cr (Ⅵ) with the initial concentration of50mg/L was1.68mg/g, the removal rate was38.74%. The orthogonal test and single factor test were used to prepare the graft composite copolymer material, the optimal preparation conditions were selected as:lignin and water solid-liquid ratio1:60, the mass of the crosslinker0.04g, the mass of the initiator0.0875g, temperature60℃, lignin monomer (acrylamide) mass ratio1:2.(5) Molecular sieve, calcium phosphate and acetic acid were used as the catalyst to prepare furfural in high temperature and pressure. The experimental equipment was assemblied. The effects of technological conditions such as reaction temperature, time, amount of catalysts and initial concentration of xylose on the yield of furfural are investigated. The result shows that, the optimum reaction conditions were:molecular sieve as the catalyst, the xylose initial concentration60mg/ml, catalyst1g, reaction temperature170℃, reaction time4h, the yield of furfural was about54.33%; calcium phosphate as the catalyst, the xylose initial concentration80mg/ml, catalyst1g, reaction temperature180℃, reaction time4h, the yield of furfural was about51.79%; acetic acid as the catalyst, the xylose initial concentration60mg/ml, catalyst3.5g, reaction temperature180℃, reaction time3h, the yield of furfural was about60.02%;... |
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