Conversion of aqueous extracts from thermochemical treatment of bagasse into functional emulsifiers

Synthetic emulsifiers in food industries are being replaced with a customer-friendly food ingredient that is derived from biomass using sustainable green technologies. After hydrothermal liquefaction treatment, raw bagasse (21%), pith (26%), and rind portions (25%) were obtained with reduced ash contents. As aqueous extracts, with oligosaccharides and lignin residues, it was used in the preparation of oil-in-water emulsions with 5% soybean oil. Results showed that the emulsions stabilised the oil droplets with particle size between 11 and 17 µm by steric repulsion with raw bagasse-stabilised emulsion showing a better stability at 25 °C (31 days). It was demonstrated that raw bagasse extracts, without alteration, maybe a potential unconventional source for food-grade emulsifiers by integrating a versatile thermochemical conversion of waste without the use of chemicals.     

渣油催化临氢热转化钼铁双金属催化剂的研究

Replacement of precious single metal catalysts with cost-effective, highly-dispersed composite catalysts for catalytic hydrothermal conversion of residue holds tremendous promise for the residue upgrading technologies. Organic metals were added to the feed as the oil-soluble precursors, and transformed into the catalytic active phases in this work. Physical properties and structures of the composite catalysts had been investigated by X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope and transmission electron microscopy. The composite catalysts were found to be highly efficient in the catalytic hydrothermal conversion of both model compound and residue. Increased metal dispersion and synergistic effects of two metals played indispensable roles in such catalytic system. Results showed that under the test conditions in the article, the catalyst had the best catalytic performance when the mass ratio of molybdenum to iron was 1.5.     

Synthesis of Humin-based Carbon Quantum Dots and Luminescent Properties

The unique properties of carbon quantum dots(CQDs) make them promising materials in many fields. Herein, we present a facile method for the preparation of photo-luminescent CQDs using humins as the carbon precursor for the purpose of providing a high value-added solution for this "biomass conversion process waste". The structure of the CQDs was analyzed, and the effects of reaction temperature and time on the CQDs' fluorescence were investigated. The results showed that humins were effectively carbonized during the reaction. The fluorescence intensity of humin-based CQDs initially increased with reaction temperature and time, and subsequently decreased beyond 200℃ and 4 h. Polyaromatic structures and hydrophilic groups such as O—H, C—O, —COOH and C==O groups exist in the CQDs. The huminbased CQDs have the dimension of 3～7 nm with an average size of about 5.5 nm. The highest emission intensity of blue/cyan fluorescence light at 440 nm is achieved on the excitation with UV light at the wavelength of 330 nm.     

生物质高压水热法还原氧化铁的研究

以纤维素、淀粉为还原剂,在特制高压反应釜内反应4h,探讨原料配比、还原温度及固液比对还原Fe_2O_3的影响,并借助XRD及SEM等分析了不同还原条件下还原产物的微观形貌及物相组成。结果表明,在Fe_2O_3粉末、氢氧化钠、淀粉用量分别为50%、25%、25%,温度310℃、固液比3∶20、搅拌速度420r/min的条件下,最高还原率为97%。     

可溶磷对常压水热法制备高强α-半水石膏的影响

研究了水热CaCl₂溶液中可溶磷对CaSO₄·2H₂O脱水形成α-半水石膏相以及晶形调控的影响,并从高强α-半水石膏相的晶体生长角度探讨了可溶磷的作用机理。结果表明:在98℃ 24%的水热CaCl₂溶液中,pH 的大小是决定二水石膏能否发生脱水相变反应形成α-半水石膏的主要因素;当pH不超过2.0时,可以得到针状的α-半水石膏,加入多元羧酸类媒晶剂NS后,可以得到长径比0.5～3.0的短柱状高强α-半水石膏,抗压强度超过20 MPa;可溶磷的存在可以降低体系的pH,增大α-半水石膏的过饱和度,降低晶体与液相界面的表面自由能,有利于α-HH相的形成;另一方面,酸根离子会影响到α-HH的结晶习性,减弱羧酸类媒晶剂的吸附效果。     

LNG输送管道耦合传热的数值模拟

对LNG输送管道与其周围环境之间的耦合传热过程进行分析,包括管道与保温层之间的导热以及保温层与周围环境之间的对流传热和辐射,并对LNG输送管道的冷量损失进行了较为完整的分析和计算。用数值仿真对管道周围的流场和温度场进行模拟和分析,比较了不同厚度的保温材料、Reynolds数、环境温度以及阳光辐射等对冷量损失的影响。结果表明保温材料特性对LNG输送管道的冷量损失影响较为敏感。随着保温材料热阻的增加,Reynolds数、环境温度以及阳光辐射对冷量的损失的影响逐渐减小。     

秸秆纤维素在亚/超临界乙醇中液化反应路径及5集总反应动力学模型的建立

将玉米秸秆纤维素在亚/超临界乙醇中液化反应产物划分为残渣(RE)、轻油(WSO)、重油(HO)、挥发分(VO)和气体(GAS)5个集总。根据液化过程及其产物分布,建立集总反应路径,并以此建立了5集总反应网络。对反应网络建立了动力学模型,采用遗传算法结合非线性规划的求解策略简化和优化动力学模型,求取了动力学参数包括指前因子(A)、活化能(E_a)和反应级数(n),并用所建立的动力学模型对液化过程进行了模拟计算,模拟结果表明WSO和VO收率随停留时间增加而减少,而HO和GAS则随停留时间增加而增加,这一规律与实验数据变化一致。以实验数据对动力学模型进行验证,各集总模拟计算值与实验值相关系数在0.9345～0.9995之间,吻合较好,表明所建立的动力学模型是可信的,所采取的遗传算法结合非线性规划求解策略是可行的。     

水热/溶剂热法制备CuS及其复合光催化材料的研究进展

纳米半导体金属硫化物因具有独特的光电性能而在有机污染物降解、光催化产氢、重金属离子还原等方面具有良好的应用前景.为此,本文综述了近年来利用水热/溶剂热法制备不同形貌纳米硫化铜及其复合材料和该类材料在光催化降解水中有机污染物、光解水产氢性能等方面的研究进展;同时,结合本课题组工作对该类材料的制备及应用前景做了展望,以期对该领域的研究有一定的促进作用.     

不同条件对合成水化硅酸钙结构与性能的影响研究综述

综述了水化硅酸钙的合成方法与合成条件对其结构与性能影响的研究现状,系统分析了不同钙硅比、温度、时间以及干燥条件等因素对水化硅酸钙的分子层结构和表面密度的影响规律,探讨了不同合成条件与水化硅酸钙结构与性能之间的关联度.     

共沉淀水热法制备锰锌铁氧体纳米晶及其表征

本研究采用成本低,污染少的共沉淀法制备锰锌铁氧体前驱体后再采用水热法制备出最终的纳米锰锌铁氧体粉末.利用X-射线衍射(XRD)、透射电镜(TEM)、复磁导率等测试手段对材料的形貌、粒径、和吸波性能进行了表征和分析.研究反应物的种类及配比对锰锌铁氧体吸波性能的影响,当反应物采用氯化锰、氯化锌、氯化铁,m(Mn)∶ m(Zn)∶ m(Fe) =4∶ 1∶10,得到Mn08Zn0.2Fe2O4粒子,透射电镜分析表明,其粒子呈球状,粒径在10 ～ 20 nm.网络矢量分析仪表明,当吸收厚度为2 mm时,锰锌铁氧体材料的吸波性能最佳.