Potential Value of Wood Tar as a Natural Fungicide against Valsa mali

The Valsa canker caused by Valsa mali seriously harmed the production of East Asian apples and caused very significant economic losses. Considering the chemical residues and the improvement of people’s awareness of environmental protection, there is a need for screening new green pesticides for the control of Valsa canker. Therefore, we conducted systematic evaluations on the antifungal activity of wood tar. In this research, the effective concentration (EC₅₀) of six strains of V. mali to wood tar was determined, and the EC₅₀ ranged from 69.54 to 92.81 μg/mL. After treatment with wood tar, the hyphae of V. mali broke, swelled, and deformed; the permeability of the cell membrane increased; and the activity of pectinase reduced. Moreover, the expression levels of five genes related to pectinase also decreased significantly. In addition, the activities of phenylalanine ammonia lyase (PAL) and peroxidase (POD) of apple leaves treated with wood tar also increased. On detached apple branches, wood tar also showed therapeutic and protective activities. In the 2016–2019 field experiments, wood tar also showed good efficacy against Valsa canker and promoted the formation of callus. (In the experiments from 2016 to 2019, it can be seen that the control effect of 50% wood tar and 100% wood tar in the field is above 75% and promoted the formation of callus.) This study is the first to report the bidirectional efficacy of wood tar against Valsa mali and for trunk wound healing. The above results evidenced that wood tar has great potential to be developed as a natural alternative to commercial fungicides for the management of apple Valsa canker.     

纤维素热解过程中活性纤维素的生成研究

热重分析发现活性纤维素的生成始于530 K左右,对应于失重图上的肩部及SDTA曲线中强烈的放热峰.在辐射加热闪速热裂解试验台上获取了一种可溶于水、高温下易分解、室温下呈固态且稳定存在的黄色中间产物.扫描电镜图片证明在热裂解初期纤维素经历了一个熔化和相互粘结的状态,产物的红外谱图证实了大量的羰基和羧基官能团的生成.高效液相色谱分析证明其主要成分是一系列聚合度不同的低聚糖,推断该低聚糖即为活性纤维素.     

紫外光谱法快速测定生物质乙醇/水水解液中糠醛和5-羟甲基糠醛含量

木质纤维类生物质水解过程中产生的可溶性木素、呋喃类化合物在紫外波长范围内均有吸收峰,且吸收峰相互叠加。研究提出了一种基于紫外光谱法快速测定生物质水解液中糠醛(F)和5-羟甲基糠醛(5-HMF)混合物(M)的方法。研究发现,M中5-HMF的含量百分率(W_(5-HMF))和最大吸收波长(λ_(max))存在良好的线性关系,R2=0.998 4。进一步研究表明M中W_(5-HMF)不变时,混合物浓度(cM)和吸光度值(A)之间也存在良好的线性关系,R2在0.998 6~1.000 0之间,且重现性均良好。因此,基于A,cM及λ_(max),W_(5-HMF)之间的良好线性关系,可以准确地检测出F和5-HMF的含量,其相对偏差、回收率及RSD分别为5.6%和3.7%,89%~96%,0.21%~0.85%。该方法简单、快捷、准确,适应于乙醇法精炼木质纤维类生物质水解液中F和5-HMF混合物的测定。     

A model of the chemical composition and pyrolysis kinetics of lignin

This study presents a novel approach for the chemical representation of lignin for modelling the reaction kinetics of lignin in lignocellulosic biomass. This methodology relies on the definition of dimeric pseudo-components containing phenolic functionalities, i.e., p-hydroxyphenyl, guaiacyl and syringyl groups, as measured in real biomass and native lignin through wet chemistry and spectroscopic techniques. The reactivities of the lignin pseudo-components are modelled through a series of lumped unidirectional reactions, whose product formation and reaction rate constants are optimised to replicate a comprehensive experimental dataset gathered from several works available in the literature. The new kinetic model contributes to the state-of-the-art by providing a more accurate depiction of the conversion rates, selectivity of char vs. volatiles, and aromatic composition in condensable products in line with the inherent reactivity of lignin functionalities and the empirical observations of lignin depolymerisation and thermal degradation at low (<1?K/s) and high heating rates (>50?K/s).     

Reflectance and ultraviolet spectroscopy: predicting the relative growth of Saccharomyces cerevisiae in pine biomass

Ultrasound treatment favors enzymatic attack on vegetal materials and influences biological activity. The objective of this study was to develop substrates for Saccharomyces cerevisiae based on the hydrothermal treatment and ultrasound treatment of pine needle biomass. The samples subjected to ultrasound treatment at 550?°C and 650?°C showed higher reflectance bands at around 200?nm after 80?min of ultrasound treatment and lower band gap energies associated with lower IC₃₀ values. The hydrothermal treatment with 100?min of ultrasound treatment generated more promising materials for the use of the substrates with the eukaryotic model S. cerevisiae.     

Multimode-ultrasound and microwave assisted natural ternary deep eutectic solvent sequential pretreatments for corn straw biomass deconstruction under mild conditions

Mild and effective pretreatments are essential to deconstruct lignocellulosic biomass so as to reuse cellulose content for value-added products. In this study, sequential multimode-ultrasound and microwave with natural ternary deep eutectic solvent (NATDES) pretreatments were used to deconstruct corn straw and optimized factors such as NATDES, ultrasonic, and microwave parameters. Results indicated that the ultrasound-NATDES or microwave-NATDES pretreatment could remove 37.86% and 52.36% lignin, respectively. When using sequential multimode-ultrasound and microwave assisted NATDES pretreatment, the delignification efficiency increased to 61.50%, and the cellulose content increased from 34.70% to 76.08%. In addition, the delignification of sequential multimode-ultrasound and microwave assisted NATDES pretreatment (under the mild conditions of microwave heating at 60 °C and 60 min) increased to 57.39%, and the cellulose content increased to 59.98%, too. This highlighted the effect of the combined ultrasound and microwave technology. Finally, the microstructural changes of mercury intrusion porosimeters, scanning electron microscopy, thermogravimetric, X-ray diffraction and Fourier transform mid-infrared spectroscopy were conducted to confirm the effectiveness of this method to deconstruct corn straw. A mechanism of the deconstruction of corn straw biomass in NATDES with the assistance of the sequential multimode-ultrasound and microwave heating was proposed. This research could open a window for future use of biomass energy by deconstructing lignocellulosic biomasses using environmentally friendly pretreatment methods.     

A hybrid EDC/Flamelet approach for modelling biomass combustion of grate-firing furnace

This paper proposes a new combustion model for the simulation of biomass combustion. It is developed based on the framework of the well-known Eddy Dissipation Concept (EDC) approach, which has the ability to incorporate chemical kinetics in turbulent reacting flows and thus makes it suitable for modelling gas-phase combustion. However, its high computational cost when using detailed chemistry has made it impractical for modelling large/industrial setups. To address this handicap, the proposed approach decouples the real-time calculation of chemical and mixing processes by importing a pre-calculated steady laminar flamelet library into EDC. The development of this new model is performed based on a modified version of EDC (called Extended EDC), which is capable of modelling the gas-phase of biomass combustion over a wide range of turbulent flow conditions. The proposed model is validated by simulating the well-documented experiment of the piloted jet flames of Barlow and Frank. The performance of the model is then evaluated by simulating a small-scale grate firing biomass furnace. The results show that, overall, the proposed model can be used to model biomass combustion at substantially low computational cost.     

微生物量对印染废水中的基质去除速率的影响

基于Monod方程,引入微生物量函数,建立了考虑微生物量作用的基质去除速率方程,并利用基质去除的零级反应速率求解有关参数.活性污泥好氧处理印染废水时,所需要的微生物量与反应时间密切相关,当HRT为24h,MLSS为2.2g·L-1,基质去除率为83%;而当HRT为12h,要达到相同的基质去除率,MLSS须维持在4.0g·L-1.当MLSS≤2.5g·L-1,基质去除速率与微生物量成正比;当MLSS为4.0g·L-1,基质去除速率约为最大值的86.2%,而且MLSS≥4.0g·L-1,基质去除速率随MLSS的变化不明显.所建立的基质去除速率方程能够较好地反映微生物量对基质去除速率的影响.     

Nitrogen‐Doped Ordered Mesoporous Carbon Supported Bimetallic PtCo Nanoparticles for Upgrading of Biophenolics

Hydrodeoxygenation (HDO) is an attractive route for the upgrading of bio‐oils produced from lignocellulose. Current catalysts require harsh conditions to effect HDO, decreasing the process efficiency in terms of energy and carbon balance. Herein we report a novel and facile method for synthesizing bimetallic PtCo nanoparticle catalysts (ca. 1.5 nm) highly dispersed in the framework of nitrogen‐doped ordered mesoporous carbon (NOMC) for this reaction. We demonstrate that NOMC with either 2D hexagonal (p6m) or 3D cubic (Im m) structure can be easily synthesized by simply adjusting the polymerization temperature. We also demonstrate that PtCo/NOMC (metal loading: Pt 9.90 wt %; Co 3.31 wt %) is a highly effective catalyst for HDO of phenolic compounds and “real‐world” biomass‐derived phenolic streams. In the presence of PtCo/NOMC, full deoxygenation of phenolic compounds and a biomass‐derived phenolic stream is achieved under conditions of low severity.     

生物质灰对煤焦加氢气化的催化作用

以小麦秸秆、马尾藻和山苦荬等三种富含碱金属和碱土金属的生物质为原料,研究了在500、600和815℃下制得的生物质灰对神府煤焦加氢气化的催化作用。结果表明,随着制灰温度由500℃升高至815℃,灰产量减少,且灰中的碱金属和氯元素的含量降低;当制灰温度达到815℃,生物质灰出现明显的熔融现象;600℃灰样对神府煤焦加氢气化具有较好的催化作用,催化效果随灰样添加比例增大而增强。山苦荬灰催化作用较好,而马尾藻灰催化作用较弱。小麦秸秆灰中较高的硅含量和马尾藻灰中较高的氯含量是其催化作用较弱的主要原因;氯元素会加剧碱金属的挥发,弱化与其结合的碱金属的催化效果,对碱金属催化所产生的抑制作用比相同摩尔数的硅更加明显。