可生物降解PBAT/PLA/生物质垃圾袋的制备和表征

将聚己二酸/对苯二甲酸丁二酯（PBAT）和聚乳酸（PLA）进行共混,然后添加竹粉、木质素和秸秆粉,利用混合熔融造粒、挤出吹膜工艺制备了PBAT/PLA/生物质粉（BP）（质量比74.26/4.95/19.80）复合垃圾袋,并采用扫描电子显微（SEM）、红外光谱仪（FTIR）、X射线衍射测试（XRD）、热重分析仪（TG）及差示扫描量热仪（DSC）等对垃圾袋的微观形貌、组成、耐热性能、拉伸性能及抗漏性能进行了测试和表征,对其实用性进行了评估。结果表明,3种BP在PBAT/PLA基体中分散性较好,对薄膜结构和热性能几乎没有影响;添加竹粉和木质素材料的垃圾袋相比于添加秸秆粉的垃圾袋有明显的强度优势,强度提高了40 %以上。本研究对于降低PBAT/PLA垃圾袋的生产成本、促进生物降解材料的产业化应用具有重要借鉴意义。     

Laser-assisted preparation of monolithic acidic catalysts for biomass conversion

5-(Hydroxymethyl)furfural (5-HMF) is a vital platform molecule from which a variety of high-value-added fine chemicals and polymerizable monomers can be prepared. The use of solid acids to catalyze the conversion of biomass into 5-HMF is environmentally friendly and economical. However, exploiting the high yield of 5-HMF in a highly concentrated reactant system is challenging. Herein, we present a laser-assisted method for preparing highly acidic monolithic acidic catalysts. A monolithic acidic catalyst based on metal Zr sheets was synthesized and used to catalytically convert 30 wt% fructose into 5-HMF (conversion rate: 96%; yield: 95%). The catalyst was immediately separated from the reaction solution by direct removal at the end of the reaction. Catalytic efficiency was largely unaffected after 10 cycles of use, and the same catalytic efficiency was observed after laser-regeneration, highlighting the potential industrial applicability of the developed catalyst.     

生物质基石墨烯复合材料的综述

近年来石墨烯因其优良的力学、电学、热学和光学等特性,在学术界备受广泛关注。石墨烯与生物质分子之间能够通过共价或非共价作用（氢键、π-π作用、静电作用等）进行复合。这些相互作用既增加了石墨烯在生物质中的溶解性或分散性,也可以提高复合材料的性能,从而拓展其功能。本文综述了石墨烯的制备方法及生物质基石墨烯复合材料的制备及应用,并展望了生物质基石墨烯纳米材料的前景及意义。     

纤维素/生物质热解生成脱水糖衍生物的机理以及选择性制备技术研究进展

纤维素/生物质快速热解过程中会形成多种脱水糖衍生物,包括左旋葡萄糖酮(LGO)、1,4:3,6-二脱水-α-D-吡喃葡萄糖(DGP)、1,5-脱水-4-脱氧-D-甘油基-己-1-烯-3-阿洛酮糖(APP)和1-羟基-3,6-二氧二环[3.2.1]辛-2-酮(LAC)等,这些脱水糖衍生物均具有很高的化工应用价值。然而在常规热解过程中,这些产物的产率都非常低,使得后续的分离提取十分困难;而在适当的催化热解条件下,其产率可以大幅提升,从而实现目标产物的选择性制备。基于此,本文首先概述了国内外学者对这4种脱水糖衍生物热解生成机理的实验以及密度泛函理论研究;随后总结了针对LGO和LAC这两种产物,现阶段已开发的选择性热解制备技术,包括最佳的催化剂以及催化热解反应条件;最后提出了未来在脱水糖衍生物生成机理以及选择性制备技术方面需要开展的工作。     

基于PY-GC/MS的生物质组分间相互作用的热解实验

为研究生物质三组分间热裂解过程中的相互作用,利用热裂解-气相色谱/质谱联用仪（PY-GC/MS）联用的方法,对纤维素、木聚糖（半纤维素的模化物）和木质素进行单独热裂解及两两组分混合热裂解实验。单组分实验结果表明,在热解温度600℃、热解时间10s条件下纤维素的热解产物主要以左旋葡聚糖为主,木聚糖以乙酸和糠醛为主,而木质素主要以酚类物质为主。组分混合热裂解实验结果表明,纤维素促进了木聚糖热裂解生成更多的乙酸和糠醛,而木聚糖和木质素对纤维素热解生成左旋葡聚糖具有强烈的抑制作用;纤维素和木聚糖的存在大大促进了木质素热裂解生成酚类物质,而木质素抑制了木聚糖热裂解生成乙酸和糠醛。此外,研究还发现混合组分热解的相互作用受到热解温度和停留时间的影响。     

Effects of formaldehyde on fermentable sugars production in the low-cost pretreatment of corn stalk based on ionic liquids

Low cost processing of lignocellulosic biomass is of great importance for sustainable chemistry and engineering. Herein, a low cost system composed of 1-butyl-3-methylimidazolium chloride ([C₄C₁im]Cl), HCl and formaldehyde (FA) was developed for the pretreatment of corn stalk at 80℃. The efficiency of this technology was compared with that in dioxane system or without FA addition. Due to FA stabilization, the extent of acid-hydrolysis of carbohydrate fraction can be significantly decreased while 70% above of lignin was removed with the pretreatment of[C₄C₁im]Cl/HCl/FA system at 80℃ for 2 h. A maximum reducing sugar yield of 93.7% and glucose concentration of 7.0 mg·ml^-1 were subsequently obtained from enzymatic hydrolysis of the slurry. There were great differences in compositions of small molecule degraded products obtained with FA addition or not. The present[C₄C₁im]Cl based system exhibits great potential of substituting volatile organic solvents (i.e. dioxane) in developing low cost lignocellulosic biomass pretreatment at low temperature. Also, this work would gain insight into understanding on the roles of stabilization methods on the economic improvement of IL based biomass processing.     

Steam pretreatment of Salix to upgrade biomass fuel for wood pellet production

Steam explosion (SE) pretreatment is served to separate the main components of woody biomass. In general there is a noticeable gap in literature in terms of application of steam explosion process to upgrade biomass fuel for wood pellet production. In order to study the influence of steam explosion pretreatment on biomass fuel, Salix wood chips was used as raw material. Four different SE experiments were performed by varying two key process factors; time and temperature. Elementary quality and ash properties of the pretreated residue were investigated. Moreover, physical and thermochemical properties of the pellet, produced from the residue, were also investigated. Reduction in ash content especially in alkali metals was observed in steam treated residue. Pretreatment of biomass also enhanced carbon content and reduced oxygen amount in the fuel which enhanced the heating value of the fuel. Moreover, pretreatment enhanced pellet density, impact resistance, and abrasive resistance of pellet. However, small degradation in ash fusion characteristics and char reactivity was also observed as the severity of the process increased.     

Pyro-catalytic deoxgenated bio-oil from palm oil empty fruit bunch and fronds with boric oxide in a fixed-bed reactor

The catalytic effect of boric oxide on the pyrolysis of empty palm oil fruit bunch (EFB) and oil palm fronds (OPF) in a fixed-bed reactor at 400 °C was investigated. Boric oxide was found to selectively reduce 50-80% of the hydroxyl and methoxy groups in both water soluble (WS) and non water soluble (NWS) fractions of the oil. The increase in water and char yield suggested that pyro-catalysis of boric oxide enhanced the cleavage of C-O bonds in the biomass polymers and the capability to retain the inherent oxygen of the biomass in the solid product. This allows organic compounds with less oxygen substitution to become volatile and condenses as bio-oil. A mechanism for pyrolysis of boric oxide with biomass showing the hydroxyl removal pathway is proposed in this study.     

Catalytic hydrothermal conversion of cellulose over SnO2 and ZnO nanoparticle catalysts

The hydrothermal conversion of cellulose in the presence of nanometal oxide particles (SnO₂ and ZnO) was investigated in this study. Both catalysts were synthesized hydrothermally and characterized using TEM, FESEM-EDX, X-ray diffraction spectroscopy and BET (Brunauer, Emmett and Teller) methods. In order to reveal the effect of nano-scale catalysts, experiments were conducted using bulk (non-nano) metal oxide and pure cellulose without any catalyst. The hydrothermal conversion experiments were carried out in a micro autoclave at 300, 400, 500, 600 °C and 1 h reaction time. The compositions of the gaseous products and the aqueous phase were determined with various analytical techniques (GC, ion chromatography, HPLC, UV-vis). Contribution of carbon containing products to the carbon mass balance was also represented. The results indicated both nano and bulk ZnO and SnO₂ to have an effect on the water-gas shift reaction at varying temperatures. The water-gas shift reaction (WGS) proceeded fast at 300 °C in the presence of ZnO, while the rate of WGS was lower at 300 °C in the presence of SnO₂. Nano ZnO led to improved hydrogen yield, while ethane and propane were formed as a result of side reactions in the presence of nano and bulk SnO₂.     

高孔隙率YSZ-高致密YSZ薄膜共烧复合体的制备

在中温固体氧化物燃料单电池制备过程中,用聚乙烯吡咯烷酮包裹改性的石墨粉体为造孔剂,以8%(摩尔分数)Y2O3稳定的ZrO2(8%in mole yttria stabilized zirconia,YSZ)粉体+石墨造孔剂为支撑层原料,与自制的水系流延YSZ电解质薄膜一起共压,制备了YSZ+石墨–YSZ薄膜复合体,在1 470℃下共烧4 h后获得高孔隙率YSZ–高致密YSZ薄膜共烧复合体。研究了不同溶剂体系中石墨含量和粒度对共烧体的影响。结果表明:选用粒径为6μm以下的石墨粉体作造孔剂能获得无开裂的多孔YSZ–YSZ薄膜共烧体,其共烧体为双层结构,层间结合紧密、结构均匀,孔隙率高达68%(体积分数)。在造孔剂的含量变化与材料烧成收缩率的关系中,造孔剂含量存在1个最佳含量值,当造孔剂含量在最佳值附近时,制备的共烧复合体质量最好。该最佳含量值随造孔剂颗粒尺寸大小不同而变化。