Hydrogen production by supercritical water gasification of lignin over CuO–ZnO catalyst synthesized with different methods

In this study, lignin was gasified in supercritical water with catalysis of CuO–ZnO synthesized by deposition precipitation, co-precipitation and sol-gel methods. Sol-gel synthesized CuO–ZnO showed the highest catalytic performance, and the gasification efficiency was increased by 37.92% with it. The XRD, SEM-EDS and N₂ adsorption/desorption analysis showed that the priority of the sol-gel catalyst was the smallest crystallite size, largest specific surface area and high dispersion. For sol-gel synthesized CuO–ZnO, the increase of CuO/ZnO ratio improved the gasification efficiency but reduced H₂ selectivity. And the catalytic activity was reduced with the calcination temperature above 600 °C due to enlarged crystallites and reduced pores. During sol-gel preparation, both the addition of ethanol and PEG in the solvent reduced the agglomeration and improved the catalytic activity. With CuO–ZnO prepared with 1 g PEG + water as the solvent, the highest H₂ yield of 6.86 mol/kg was obtained, which was over 1.5 times of that without catalyst.     

Lignin from Annual Plants as Raw Material Source for Flavors and Basic Chemicals

The enzymatic conversion of lignins, possibly in combination with electrochemical oxidation, makes aromatics such as syringol, guaiacol, vanillin and catechol available in the qualities required by the fragrance industry. The lignins were obtained by soda digestion from wheat straw and Miscanthus, characterized and then converted with laccases. The overall yield amounted up to 9 wt % with a product spectrum confined to four substances. Catechol was the major product, with a fraction of ≈75 %. It can easily be isolated by extraction with acetone.     

The Present Status and Potential of Kraft Lignin-Phenol-Formaldehyde Wood Adhesives

Kraft lignin (KL), a phenolic polymer formed during the kraft pulping process, is presently burned as a low value fuel. For decades, researchers have attempted to use KL as an inexpensive substitute for phenol in phenol-formaldehyde (PF) resins, but no one has produced a commercially satisfactory KL-PF resin. This paper reviews the literature on the present status of KL-PF adhesives and makes recommendations on needed research.

Kraft lignin solutions are complex mixtures which have broad molecular weight distributions, high viscosities, relatively low reactivities, and low solubilities. Attempts to overcome these inherent problems include methylolation of lignin to improve reactivity, the use of co-solvents to improve solubility, and ultrafiltration to yield more homogeneous molecular weight fractions. Future research efforts need to focus on understanding the fundamental chemical and physical properties of kraft lignin and its resins. The search for an economic lignin-based wood adhesive should continue.     

Hydrothermal upgrading of wood biomass: Influence of the addition of K2CO3 and cellulose/lignin ratio

The hydrothermal treatment of two different wood biomass samples such as cherry (hard wood) and cypress (soft wood), whose composition is different i.e. lignin, cellulose and hemicellulose were performed at 280 °C for 15 min with aq. K₂CO₃ with different concentrations (0–1 M). The soft wood biomass contains higher lignin content than hard wood biomass. The cellulose rich cherry wood biomass produced higher proportion of acetic acid than cypress. The lignin rich cypress produced the hydrocarbons with major portion of phenolic hydrocarbons and derivatives than cherry. The total oil yields from both cherry and cypress wood biomass produced 50 wt% of liquid hydrocarbons at 280 °C for 15 min with 0.5 M K₂CO₃ solution. The volatility distribution of liquid hydrocarbons showed the characteristic features of soft and hard wood biomasses.     

染料分散剂新原料-高沸醇木质素的研制

采用1，4-丁二醇水溶液为溶剂的高沸醇溶剂法，从松木，杉木，稻草等原料制备纤维素与高沸醇木质素。使用上述原料，在70%-90%1，4-丁二醇水溶液中添加少量催化剂。并在190℃-220℃条件下蒸煮1-3小时后，分离反应产物，得到固体纤维素与高沸醇木质素-丁二醇溶液，不溶于水的高沸醇木质素通过加水沉淀的方法。从反应后的液体混合物中分离。高沸醇木质素具有较高的反应活性。灰分含量很低。适于制备新型染料分散剂，有广泛应用前景。     

木质素-EVA扭矩流变性能试验研究

研究了影响木质素与乙烯醋酸乙烯酯共聚物（EVA）共混物在扭矩流变仪中的共混最大扭矩、平衡扭矩以及达到平衡扭矩时间的各个因素。结果表明，木质素、增容剂、增塑剂、转速、温度对扭矩值有明显影响；木质素／EVA共混体系达到平衡扭矩时的平均时间随木质素的含量增加，扭矩值减小到最小后又逐渐增加。木质素／EVA共混物热溶胶的粘度表现出非牛顿流体的假塑性流体，热溶胶粘度随温度的上升而减小，木质素／EVA共混体系具有可加工性。     

木素-UF胶粘剂的研制

本文介绍了一种木素－UF胶粘剂的制造方法，并分析了木素羟甲基化、过程pH值、尿素加料次数及木素加量对胶粘剂性能的影响。     

Valorization of Eucalyptus wood by glycerol-organosolv pretreatment within the biorefinery concept: An integrated and intensified approach

The efficient utilization of lignocellulosic biomass and the reduction of production cost are mandatory to attain a cost-effective lignocellulose-to-ethanol process. The selection of suitable pretreatment that allows an effective fractionation of biomass and the use of pretreated material at high-solid loadings on saccharification and fermentation (SSF) processes are considered promising strategies for that purpose. Eucalyptus globulus wood was fractionated by organosolv process at 200 °C for 69 min using 56% of glycerol-water. A 99% of cellulose remained in pretreated biomass and 65% of lignin was solubilized. Precipitated lignin was characterized for chemical composition and thermal behavior, showing similar features to commercial lignin. In order to produce lignocellulosic ethanol at high-gravity, a full factory design was carried to assess the liquid to solid ratio (3–9 g/g) and enzyme to solid ratio (8–16 FPU/g) on SSF of delignified Eucalyptus. High ethanol concentration (94 g/L) corresponding to 77% of conversion at 16FPU/g and LSR = 3 g/g using an industrial and thermotolerant Saccharomyces cerevisiae strain was successfully produced from pretreated biomass. Process integration of a suitable pretreatment, which allows for whole biomass valorization, with intensified saccharification-fermentation stages was shown to be feasible strategy for the co-production of high ethanol titers, oligosaccharides and lignin paving the way for cost-effective Eucalyptus biorefinery.     

Slow and fast pyrolysis of Douglas-fir lignin: Importance of liquid-intermediate formation on the distribution of products

The formation of liquid intermediates and the distribution of products were studied under slow and fast pyrolysis conditions. Results indicate that monomers are formed from lignin oligomeric products during secondary reactions, rather than directly from the native lignin. Lignin from Douglas-fir (Pseudotsuga menziesii) wood was extracted using the milled wood enzyme lignin isolation method. Slow pyrolysis using a microscope with hot-stage captured the liquid formation (>150 °C), shrinking, swelling (foaming), and evaporation behavior of lignin intermediates. The activation energy (E_a) for 5–80% conversions was 213 kJ mol⁻¹, and the pre-exponential factor (log A) was 24.34. Fast pyrolysis tests in a wire mesh reactor were conducted (300–650 °C). The formation of the liquid intermediate was visualized with a fast speed camera (250 Hz), showing the existence of three well defined steps: formation of lignin liquid intermediates, foaming and liquid intermediate swelling, and evaporation and droplet shrinking. GC/MS and UV-Fluorescence of the mesh reactor condensate revealed lignin oligomer formation but no mono-phenols were seen. An increase in pyrolytic lignin yield was observed as temperature increased. The molar mass determined by ESI-MS was not affected by pyrolysis temperature. SEM of the char showed a smooth surface with holes, evidence of a liquid intermediate with foaming; bursting from these foams could be responsible for the removal of lignin oligomers. Py-GC/MS studies showed the highest yield of guaiacol compounds at 450–550 °C.     

Preparation of Iron Oxide Particle-Decorated Lignin-Based Carbon Nanofibers as Electrode Material for Pseudocapacitor

Iron oxide particle-decorated lignin-based carbon nanofibers (IO-LCNFs) were fabricated from organic mixtures containing acetic acid lignin (AAL) together with ferric acetylacetonate (Fe(acac)₃) via electrospinning followed by stabilization in air and carbonization in nitrogen. After the addition of Fe(acac)₃, IO-LCNFs showed different morphologies: Non-fused IO-LCNFs were obtained with diameters of 400–500 nm; iron oxide nanoparticles with diameters of 30–60 nm were exposed outside and well-distributed when sufficient amounts of Fe(acac)₃ were added. These carbon nanofibers were then used as electrode material for pseudocapacitor. It was found that the iron oxide particles enhanced the resulting electrochemical properties via reversible redox reactions. IO-LCNFs made from the composite nanofibers with mass ratio of AAL/Fe(acac)₃ of 80/20 [i.e., IO-LCNFs (80/20)] exhibited the highest specific capacitance, 72.1 F g^?1, at current density of 500 mA g^?1.