碳酸钠预处理对麦草酶水解及木质素结构的影响

麦草原料茎秆和叶子的形态构造与化学组成的差异影响其碳水化合物的酶水解转化效率。研究比较了碳酸钠预处理对麦草茎秆和叶子的组分构成及酶水解转化效率的影响,并用化学降解方法分析了预处理后茎秆和叶子木质素结构变化。结果表明:麦草叶子在碳酸钠预处理下具有较好的脱木质素选择性,叶子经以原料绝干重为基准的碳酸钠(质量分数8%)、温度140℃预处理,在10μmol/(min·g)酶用量下的总糖转化率比茎秆高29%。碱性硝基苯氧化和臭氧降降解研究表明,叶子与茎秆木质素存在显著的结构差异,其紫丁香基结构单元和β-O-4连接键含量均较低。碳酸钠预处理后,叶子木质素的碱性硝基苯氧化和臭氧解产物得率的降幅高于茎秆木质素,表明叶子在预处理过程中有更多的β-O-4键发生断裂。由此可以推断,碳酸钠预处理麦草茎秆和叶子的酶水解转化效率与其木质素结构差异存在一定关系,木质素含量及结构是影响木质纤维原料酶水解的重要因素之一。     

Structure properties of pyrolytic lignin extracted from aged bio-oil

Fast pyrolysis is a promising technology that can convert biomass into liquid.Bio-oil is one such product,known not only as a greenhouse gas-neutral energy source,but also an opportunity to reduce reliance on fossil fuels.Pyrolytic lignin,a fine homogeneous powder,is the water-insoluble fraction of bio-oil and it contributes to the instability of bio-oil.Additionally,pyrolytic lignin can be used in commercial materials such as adhesives in the wood-based panel industry.This paper presents the structural characterization of pyrolytic lignin extracted from aged bio-oil and the relationship between its properties and the treatment temperature of the aged bio-oil.Pyrolytic lignin samples were characterized by Fourier transform infrared spectroscopy,gel permeation chromatography,differential scanning calorimetry,thermogravimetric analysis and proton nuclear magnetic resonance spectroscopy.The average molecular weight of pyrolytic lignin increased from 700 to 1000 g/mol with increasing aging temperature (6-50°C).Differential scanning calorimetry showed that the glass transition temperature of pyrolytic lignin increases with lower heating rate and higher treatment temperature of bio-oil.An increase in the initial decomposition temperature and the temperature at 95 wt% weight loss of the aged pyrolytic lignin in thermogravimetry were observed for the bio-oil aged at higher temperature.An increase in residue weight of aged pyrolytic lignin was found in bio-oil aged at higher temperatures.     

十二系列叔胺捕收剂对高岭石的浮选研究

研究4种十二取代叔胺（DRN,DEN,DPN和DBN）对高岭石的浮选行为。发现4种叔胺对高岭石的浮选捕收能力都较好,其中DEN最好,浮选回收率最高可达92 %以上。4种叔胺主要依靠静电引力吸附在高岭石表面,在酸性pH范围内,浮选高岭石的回收率较高,随着pH的增大,叔胺的阳离子组分减少,使得浮选回收率下降。Zeta电位研究表明,高岭石在整个pH范围内,表面主要带负电,4种叔胺与高岭石作用后,能显著增加高岭石的Zeta电位。红外光谱研究表面,4种叔胺主要与高岭石表面发生了电性作用的物理吸附。叔胺中N原子上的取     

Action of the saproxylic scarab larva Cetonia aurataeformis (Coleoptera: Scarabaeoidea: Cetoniidae) on woody substrates

The saproxylic beetle Cetonia aurataeformis Curti (Scarabaeoidea: Cetoniidae) is a common Iberian species, whose larvae develop in tree cavities feeding on wood and litter. The aim of this paper is to analyse how the larvae of this cetonid modify the woody substrate by feeding and what the ecological implications on their microhabitat could be. Thermal analysis and infrared spectroscopy have been used to study the changes suffered by different substrates, litter and wood of Betula alba and Quercus pyrenaica, after digestion by the larvae. Results show that larvae of C. aurataeformis are able to digest polysaccharides and lignin producing a residue richer in nutrients than the original substrate and with an organic structure that contains a fraction of lignin that is easier to decompose. The main conclusion is that the action of cetonid larvae on woody substrates could facilitate their use by other saproxylic organisms in natural ecosystems.     

关于制浆造纸厂废液中木质素在工业上的应用探讨

对制浆废液中所含大量的木质素应用可行性进行了初步分析，提出木质素工业应用的一些有效途径。     

水相pH值、水相介质及温度对N1923界面吸附性能的影响

研究了平衡水相pH值、水相介质及温度对伯胺N1923正庚烷／H2O液-液体系界面性质的影响，计算了界面吸附特性参数Cmin和AⅠ,发现N1923的界面活性随平衡水相酸度、介质浓度或电荷的增加而增加，随温度升高而下降，并对有关结果及其与萃取性能的关系作了分析和讨论．     

微生物酸化技术应用于碱法草浆黑液酸析木素的试验研究

碱法草浆黑液碱性大、木素含量高、成分复杂,极难处理,利用微生物酸化技术将黑液预酸化,在不添加任何营养的条件下,不仅可使pH值下降至中性,而且CODcr、木素含量均有所下降,再经酸析木素比直接酸析木素节约用酸40%左右,极大的降低了处理成本,提高了处理效率。     

木质素化学改性研究进展

木质素是自然界中来源丰富的可再生芳香族聚合物,可用于高附加值化学品、生物燃料、建筑材料和高分子材料的制备,但因其结构复杂,直接工业应用有限.通过化学或物理的方法作用于天然木质素结构中的某些活性基团,可改变其特性.改性后的木质素特性优良,在工业上得到了更好的应用.介绍了木质素的结构组成、主要化学改性方法及改性后木质素在表面活性剂、减水剂、树脂材料及香精香料等方面的应用,为木质素的进一步研究提供参考.     

高效木质素降解菌的筛选及降解性能研究

【目的】筛选纯化及鉴定木质素降解菌,对其降解性能进行初步研究。【方法】从某制浆造纸厂的造纸废水污泥中,筛选获得2株具有木质素降解能力的细菌LD-1和LD-2。通过形态观察和16SrRNA序列分析对菌株进行鉴定;采用苯胺蓝平板脱色法及以TC为指标分别定性定量测定2株细菌的木质素降解能力。【结果】LD-1和LD-2分别被鉴定为Sphingobacterium属和Bacillus属的菌株,命名为Sphingobacterium sp.LD-1和Bacillus sp.LD-2。通过苯胺蓝平板脱色实验,发现LD-1和LD-2均具有良好的木质素降解能力。经测定,两株菌种发酵7d对木质素的降解率分别达到52.23%和50.36%。【结论】成功筛选到2株能高效降解木质素的菌株LD-1和LD-2。     

水性环氧树脂改性水泥砂浆性能的研究

合成了高沸醇木质素环氧树脂亲水衍生物和水性环氧树脂乳液，并用红外光谱对高沸醇木质素环氧树脂亲水衍生物进行了表征．研究了乳化剂用量对水性环氧树脂稳定性的影响，并用环境扫描电镜对试样形貌进行了表征．结果表明，当乳化剂用量大于环氧树脂质量份的13％时，水性环氧树脂稳定；水性环氧树脂乳液对水泥砂浆韧性的改善要好于高沸醇木质素环氧树脂亲水衍生物；环境扫描电镜结果表明，聚合物在水泥水化产物表面形成了三维结构．