改性木素的絮凝脱色作用

以造纸黑液中提取的木素为合成原料,通过Mannich反应使木素胺化改性;以氮元素含量来确定木素的改性率;采用正交实验来确定温度、甲醛和己二胺的用量对木素改性率的影响,从而确定最佳工艺条件。比较了超声活化对木素的胺化改性效果的影响。通过红外、电镜对木素和改性木素的结构进行了分析,并用改性木素进行了品红溶液的絮凝脱色实验,研究了脱色时间和改性木素用量对品红溶液脱色效果的影响。结果表明,影响木素改性率的主要因素是甲醛用量和温度,改性木素对品红溶液具有很强的絮凝脱色效果,当脱色时间为100 min、样品用量为10 mg（即0.5 g/L）时脱色率高达93%。     

化学改性在木素基酚醛树脂胶黏剂制备中的研究进展

综述了木素磺酸盐、碱木素、酶解木素等应用于改性酚醛树脂胶黏剂的发展现状,以及几种常用于提高木素反应活性的化学方法,分析木素改性酚醛树脂存在的问题并对其应用前景进行了展望。     

木素的曼尼希反应改性

曼尼希(Mannich)反应是一个重要的有机反应,在医药和生物碱的合成中有着重要的应用价值.木素的Man-nich反应为木素的改性开辟了新领域,极大地拓展了木素的应用范围.本文在概述Mannich反应机理的基础上,对木素模型化合物的Mannich反应及木素的Mannich改性研究进展进行了综述,并对木素Mannich反应改性产物在沥青乳化、污水处理、石油开采、固体颗粒分散和橡胶中的应用作了扼要的介绍.     

氧化改性木素磺酸钙的制备及其对水泥净浆的影响

采用H_2O_2对木素磺酸钙进行氧化改性处理,通过正交实验确定最佳改性条件,再对改性产物进行红外光谱(FT-IR)分析和扫描电子显微镜(SEM)表征,并对比了改性前后木素磺酸钙对水泥净浆流动度和水泥早期水化产物的影响。结果表明,改性后的木素磺酸钙吸附能力大大增强,当在水泥净浆中掺加0.6%的改性木素磺酸钙后,水泥净浆流动度提高了67%。X射线衍射仪(XRD)的测试结果表明,改性前后木素磺酸钙均会抑制Ca(OH)_2的生成,但改性后抑制效果减弱,一定程度上减弱了木素磺酸钙对水泥的缓凝作用。     

木素利用新技术

综述了木素的几种改性方法 ,以及经过改性后的木素在工业及农林业中的应用     

橡碗废渣制改性木素磺酸鞣剂的研究

橡碗经浸提制取栲胶后,排除大量橡碗废渣,造成环境污染。本研究的目的是从橡碗废渣中提取木素,通过改性,得到木素磺酸鞣剂。本文根据改性应用实际要求,研究了从橡碗废渣中提取木素磺酸的工艺条件,确定了适宜的浸提工艺;同时还研究了用铬、铝盐共同改性浸提液的方法。研究结果表明,木素磺酸铬铝鞣剂是一种具有新的特性的鞣剂。     

木素胺化改性制备重金属吸附剂

以木素为原料,通过胺化改性制备木素基重金属吸附剂,吸附Pb2+。实验中首先将木素用琥珀酸酐进行酸酐改性,然后以对甲苯磺酰氯为催化剂与三乙烯四胺反应,得到胺化改性木素。以琥珀酸酐与木素摩尔比及反应时间为变量优化酸酐改性条件。通过测定羧基含量、红外光谱分析(FT-IR)和吸附性能分析对产物性能进行表征。结果表明,琥珀酸酐与木素摩尔比1.5∶1、反应时间1 h、温度28℃、pH值8.5~9.0时,所得酸酐改性木素中羧基含量最高,达1.98 mmol/g;FT-IR谱图分析显示木素改性成功;胺化改性木素对Pb~(2+)吸附符合拟二阶动力学模型和Freundlich模型,同时随着pH值的升高,产物吸附性能随之提高,p H值5时吸附性能降低,在p H值为5时胺化改性木素对Pb~(2+)的吸附量达到152.95 mg/g。     

以本素衍生物为原料制备环氧树脂

本文综述了以木素为原料与环氧化合物进行化学改性,改性后的木素衍生物与环氧氯丙烷进行环氧化,生成木质基环氧树脂,以及木质基环氧树脂的固化。     

木素磺酸盐产品的应用研究

主要介绍了木素磺酸盐的结构、特性和来源,及其改性产品在分散剂方面、钻井泥浆稀释剂方面、减水剂方面、粘结剂方面的应用。木素磺酸盐在分散剂方面应用较广,产品种类较多。期望加强木素磺酸盐系列产品的开发与应用,实现木素磺酸盐应有价值。     

以木素衍生物为原料制备环氧树脂

本文综述了以木素为原料与环氧化合物进行化学改性，改性后的木素衍生物与环氧氯丙烷进行环氧化，生成木质基环氧树脂，以及木质基环氧树脂的固化。     

纸浆物理强度与纤维表面木素含量关系的探讨

通过酸析木素的方法在漂白硫酸盐浆纤维表面沉积木素,探讨了纸浆纤维表面木素含量对纸浆强度性能的影响.研究结果表明,随着硫酸盐木素溶液pH值的降低,木素在纸浆纤维表面的沉积吸附量增加;经过打浆作用的纸浆纤维暴露出更多的表面,能够吸附更多的木素;纸浆纤维表面木素含量与纸浆的抗张指数、耐破指数呈负的线性相关性,相关方程式分别为y=-1.23x +56.9(R=0.99)和y=-0.104x +4.62(R=0.96);增加纤维表面木素含量会降低纸浆纤维间的结合强度.     

工业木素的氨化反应研究及其进展

从反应的影响因素、产物的氮键类型和结构等方面,介绍了木素氧化氨解过程可能的反应机理,并详述了国内外关于工业木素氧化氨解工艺及其相应产品应用的研究进展,为我国工业木素资源的农业利用提供科学依据。     

麦草组分水热-乙醇两步法处理过程中木素在纤维表面的沉积形态

本课题通过研究水热-乙醇两步法对麦草组分分离效果的影响，采用场发射扫描电子显微镜、原子力显微镜和X光电子能谱研究了木素沉积形态的变化。结果表明，水热-乙醇两步法对半纤维素脱除率高达94.2%，但是其木素的脱除率仅为41.5%；这与木素在纤维表面发生了沉积这一现象有着密不可分的关系，水热处理后部分木素以颗粒状形式沉积在固相残余物表面，而这一部分沉积的木素并不能在乙醇法处理后溶解，第二步的乙醇法处理改变了沉积木素的形态，将颗粒状木素转变为包覆层吸附在纤维表面，导致了水热-乙醇两步法对木素的脱除率较低。     

Relationship among compositional data of fibrous by-products as determined by two different extractions in the detergent system of analysis. Influence on the prediction of the digestibility

Both direct and sequential extractions in the detergent system of analysis were applied to some fibrous by-products (cereal and legume straws, legume bagasse, vine branch silage and poplar bark) to determine which gave the better prediction of the digestibility through the summative equation, and to study the interferences of fibre-bound nitrogen and tannins. Permanganate lignin gave a lower correlation than acid-detergent lignin when figures from direct and sequential extractions were compared. Fibrebound nitrogen (as N × 6.25) was positively correlated to permanganate lignin, whereas tannins were positively correlated to acid-detergent lignin. Figures for permanganate lignin from sequential extraction and aciddetergent lignin from direct extraction gave a good prediction of in-vitro digestibility when they were used in the summative equation. More research into lignin, tannins and the detergent system of analysis of fibrous by-products should be done in order to improve and clarify the prediction of digestibility.     

Lignin Interaction with Cellulase during Enzymatic Hydrolysis

The conversion of lignocellulosic biomass into biofuels or biochemicals typically involves a pretreatment process followed by the enzyme-catalyzed hydrolysis of cellulose and hemicellulose components to fermentable sugars. Many factors can contribute to the recalcitrance of biomass, e.g., the lignin content and structure, crystallinity of cellulose, degree of fiber polymerization, and hemicellulose content, among others. However, nonproductive binding between cellulase and lignin is the factor with the greatest impact on enzymatic hydrolysis. To reduce the nonproductive adsorption of enzymes on lignin and improve the efficiency of enzymatic hydrolysis, this review comprehensively summarized the progress that has been made in understanding the interactions between lignin and enzymes. Firstly, the effects of pretreatment techniques on lignin content and enzymatic hydrolysis were reviewed. The effects of lignin content and functional groups on enzymatic hydrolysis were then summarized. Methods for the preparation and characterization of lignin films were assessed. Finally, the methods applied to characterize the interactions between lignin and cellulase were reviewed, and methods for decreasing the nonproductive binding of enzymes to lignin were discussed. This review provides an overview of the current understanding of how lignin hinders the enzymatic hydrolysis of lignocellulosic biomass, and provides a theoretical basis for the development of more economical and effective methods and additives to reduce the interaction of lignin and enzymes to improve the efficiency of enzymatic hydrolysis.     

Lignin Extraction from Black Liquor and its Application Prospects in Pulp Mills

This paper summarizes the possible application of lignin extraction from black liquor and the development of lignin extraction technology.Lignin extraction from black liquor is an important,economical method to resolve the bottleneck associated with the recovery boiler and achieve the targeted capacity expansion in pulp mills.A few of key issues must be taken into cosideration when lignin extraction technology is adopted on the industrial scale.     

黄孢原毛平革菌对大豆秸秆木质素降解的FTIR表征

研究黄孢原毛平革菌(Phanerochaete chrysosporium Burdsall)对大豆秸秆中木质纤维素的降解条件。结果显示：5g秸秆粉中添加合成培养液12mL、接种量为0.8mL(孢子悬液浓度8.6×106CFU/mL)、培养基初始pH4.5,发酵10d后,木质素降解率为45.96%。并采用傅里叶红外光谱分析(Fourier transform infrared spectroscopy,FTIR) 检测降解后秸秆中官能团的变化,发现与木质素相关的谱峰(1099cm-1、1057～1038cm-1)相对强度减小,与苯环相关的谱峰(1643～1608cm-1、1510～1508cm-1)相对强度增加,表明部分大分子木质素裂解成小分子木质素或木质素单体,对比其他谱峰相对强度的变化,发现木质素中苯环等环状化合物含量减少。     

巴西甘蔗渣烧碱-蒽醌法蒸煮机理的研究

对巴西甘蔗渣原料主要成分和烧碱-蒽醌法蒸煮机理进行了研究。结果表明:巴西甘蔗渣与中国甘蔗渣相比,其克拉森木素含量低,而综纤维素的含量高。巴西甘蔗渣烧碱蒽醌法脱木素的阶段性可分为大量脱木素、补充脱木素和残余脱木素三个阶段:即蒸煮温度升至100℃时,为大量脱木素阶段,木素脱除69.44%;当蒸煮温度从100℃升至160℃,此阶段为补充脱木素阶段,此阶段脱除24.18%的木素;在160℃保温150min期间为残余脱木素阶段,此阶段脱除3.38%的木素。     

采用LignoBoost技术从制浆黑液中高效萃取木素

木素是自然界重要的天然有机物，是制浆黑液中的重要组分，不断开发黑液中木素的应用，充分实现其价值最大化是造纸业界研发的重要内容之一。采用LignoBoost技术将制浆黑液中的木素萃取出来，转化为固体生物质，提高了黑液的回收效率和对木素的综合利用。本文主要介绍了LignoBoost技术的发展历程、工艺流程和商业化案例等。     

Numerical Simulation of Microwave-assisted Depolymerization of Kraft Lignin

Kraft lignin has the potential to replace traditional fossil resources for the preparation of high-value chemicals because it is rich in aromatic rings and active functional groups. An effective method for the pyrolysis of kraft lignin into chemicals/fuels is microwave-assisted depolymerization. A simulation model is urgently needed to illustrate the coupling effect and mechanism of lignin conversion during the depolymerization process. In this study, COMSOL Multiphysics was used to simulate the microwave-assisted depolymerization process. The results showed that microwave power had a significant effect on the electric field and temperature distribution in the microwave cavity, while the reaction time had little effect on the electric field. The effect of the nitrogen flow rate on the electric field and temperature was negligible. The intensity of the electric field, heating rate of lignin, and final temperature of lignin depolymerization increased with increasing microwave power.