scholarly journals Characterization of Cellulase-Treated Fibers and Resulting Cellulose Nanocrystals Generated through Acid Hydrolysis

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1272 ◽  
Author(s):  
Dawit Beyene ◽  
Michael Chae ◽  
Jing Dai ◽  
Christophe Danumah ◽  
Frank Tosto ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Filter Paper ◽  
Crystallinity Index ◽  
Wood Pulp ◽  
Enzymatic Treatment ◽  
Biofuel Production ◽  
Pulp Fibers ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Wood Pulp Fibre

Integrating enzymatic treatment and acid hydrolysis potentially improves the economics of cellulose nanocrystal (CNC) production and demonstrates a sustainable cellulosic ethanol co-generation strategy. In this study, the effect of enzymatic treatment on filter paper and wood pulp fibers, and CNCs generated via subsequent acid hydrolysis were assessed. Characterization was performed using a pulp quality monitoring system, scanning and transmission electron microscopies, dynamic light scattering, X-ray diffraction, and thermogravimetric analysis. Enzymatic treatment partially reduced fiber length, but caused swelling, indicating simultaneous fragmentation and layer erosion. Preferential hydrolysis of less ordered cellulose by cellulases slightly improved the crystallinity index of filter paper fiber from 86% to 88%, though no change was observed for wood pulp fibre. All CNC colloids were stable with zeta potential values below −39 mV and hydrodynamic diameters ranging from 205 to 294 nm. Furthermore, the temperature for the peak rate of CNC thermal degradation was generally not affected by enzymatic treatment. These findings demonstrate that CNCs of comparable quality can be produced from an enzymatically-mediated acid hydrolysis biorefining strategy that co-generates fermentable sugars for biofuel production.

scholarly journals Effect of Mechanical Treatment of Eucalyptus Pulp on the Production of Nanocrystalline and Microcrystalline Cellulose

2021 ◽  
Vol 13 (11) ◽  
pp. 5888
Author(s):  
Walter Torezani Neto Boschetti ◽  
Ana Márcia Macedo Ladeira Carvalho ◽  
Angélica de Cássia Oliveira Carneiro ◽  
Graziela Baptista Vidaurre ◽  
Fernando José Borges Gomes ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Microcrystalline Cellulose ◽  
Kraft Pulp ◽  
Crystallinity Index ◽  
Pulp Fibers ◽  
Cellulose I ◽  
Physical Treatment ◽  
Eucalyptus Pulp ◽  
Mechanical Pretreatment ◽  
Eucalyptus Kraft Pulp

This study aimed to assess the effect of mechanical pretreatment on bleached eucalyptus kraft pulp fibers and investigate the influence of reaction time and temperature on the properties and yield of nanocrystalline cellulose (NCC) and microcrystalline cellulose (MCC). Two types of pulps were hydrolyzed, pulp 1 (control, whole fibers) and pulp 2 (mechanically pretreated, disintegrated fibers). NCC and MCC particles were obtained by sulfuric acid hydrolysis (60% w/w) of eucalyptus pulps under different conditions of time (30–120 min) and temperature (45–55 °C). Physical treatment of kraft pulp facilitated acid hydrolysis, resulting in higher NCC yields compared with no pretreatment. The morphologic properties and crystallinity index (CI) of NCC and MCC were little affected by pulp pretreatment. NCC particles obtained from pulps 1 and 2 were needle-shaped, with mean diameters of 6 and 4 nm, mean lengths of 154 and 130 nm, and CI of 74.6 and 76.8%, respectively. MCC particles obtained from pulps 1 and 2 were rod-shaped, with mean diameters of 2.4 and 1.4 µm, mean lengths of 37 and 22 µm, and CI of 73.1 and 74.5%, respectively. Pulps 1 and 2 and their respective NCC and MCC derivatives had a cellulose I crystalline structure.

scholarly journals Cellulose Nanocrystal Isolation from Hardwood Pulp using Various Hydrolysis Conditions

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3724 ◽  
Author(s):  
Kuan-Hsuan Lin ◽  
Toshiharu Enomae ◽  
Feng-Cheng Chang
Keyword(s):  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Flame Retardants ◽  
Crystallinity Index ◽  
Color Changes ◽  
Preparation Conditions ◽  
High Acid Concentration ◽  
Transmission Electron ◽  
Hardwood Pulp ◽  
Hydrolysis Conditions

To expand the application field of the pulping industry, this study conducted a series of sample preparations for processing cellulose nanocrystals (CNCs) from a dry hardwood pulp to achieve optimal sulfuric acid hydrolysis. The properties of laboratory-prepared pulp CNCs (P-CNCs) were investigated with different preparation conditions including sulfuric acid concentrations, hydrolysis temperatures, and hydrolysis durations. Results showed a gradient of color changes observed with the increase of hydrolysis duration and temperature. Under certain conditions, the derived P-CNCs exhibited nanoscale dimensions, detected by transmission electron microscopy, and a crystallinity index similar to commercial products. In addition, the surface sulfate groups were assumed to be contributed by sulfuric acid hydrolysis. However, a high acid concentration and long hydrolysis processing duration introduced more sulfate groups on the derived P-CNCs, which may have acted as flame retardants and, thus, increased the amount of char residue.

Microscopic Characterization of Cellulose Nanocrystals Isolated from Sisal Fibers

2015 ◽  
Vol 827 ◽  
pp. 174-179 ◽  
Author(s):  
Harini Sosiati ◽  
Mu'minul Muhaimin ◽  
Purwanto ◽  
Dwi Astuti Wijayanti ◽  
Harsojo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Acid Hydrolysis ◽  
Cellulose Nanocrystals ◽  
Crystallinity Index ◽  
Xrd Analysis ◽  
Air Cooling ◽  
Residual Lignin ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Sisal Fibers

Isolation of cellulose nanocrystals (CNCs) was carried out by unrepeated or repeated alkalization and bleaching followed by sulfuric acid hydrolysis and air cooling (unrepeated) or ice cooling (repeated). The influence of unrepeated and repeated alkalization and bleaching, and cooling rate (cooling medium) after hydrolysis on the morphology and crystallinity of the isolated micro- and nano-celluloses were characterized. Scanning electron microscopy (SEM) showed that repeated alkalization and bleaching led to a higher degree of fibrillated microcellulose (~10 mm) with higher surface roughness than unrepeated alkalization and bleaching. Transmission electron microscopy (TEM) revealed that air and ice cooling after acid hydrolysis producing different CNCs morphologies; heterogeneous CNCs nanowhisker and nano-spherical (~50 nm), and homogenous CNCs nanowhiskers (~50 nm width and ~500 nm length), respectively. The homogeneous nano whisker was related to single phase monoclinic b-cellulose. Residual lignin agglutinating between the nanoparticles was observed in TEM image as well as in Fourier transform infrared (FTIR) spectra. The existence of residual lignin after hydrolysis is comparable in crystalinity (crystallinity index,Ic: ~91%) with that of isolated CNCs, as confirmed by x-ray diffraction (XRD) analysis.

scholarly journals V2O3/C composite fabricated by carboxylic acid-assisted sol–gel synthesis as anode material for lithium-ion batteries

2021 ◽  
Author(s):  
G. S. Zakharova ◽  
E. Thauer ◽  
A. N. Enyashin ◽  
L. F. Deeg ◽  
Q. Zhu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Sol Gel ◽  
Carbon Sources ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Battery Electrode ◽  
Sol Gel Synthesis

AbstractThe potential battery electrode material V2O3/C has been prepared using a sol–gel thermolysis technique, employing vanadyl hydroxide as precursor and different organic acids as both chelating agents and carbon sources. Composition and morphology of resultant materials were characterized by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies, physical sorption, and elemental analysis. Stability and electronic properties of model composites with chemically and physically integrated carbon were studied by means of quantum-chemical calculations. All fabricated composites are hierarchically structured and consist of carbon-covered microparticles assembled of polyhedral V2O3 nanograins with intrusions of amorphous carbon at the grain boundaries. Such V2O3/C phase separation is thermodynamically favored while formation of vanadium (oxy)carbides or heavily doped V2O3 is highly unlikely. When used as anode for lithium-ion batteries, the nanocomposite V2O3/C fabricated with citric acid exhibits superior electrochemical performance with an excellent cycle stability and a specific charge capacity of 335 mAh g−1 in cycle 95 at 100 mA g−1. We also find that the used carbon source has only minor effects on the materials’ electrochemical performance.

Ultrastructure of commercial recycled pulp fibers for the production of packaging paper

Holzforschung ◽  
2005 ◽  
Vol 59 (6) ◽  
pp. 675-680 ◽  
Author(s):  
Jonas Brändström ◽  
Jean-Paul Joseleau ◽  
Alain Cochaux ◽  
Nathalie Giraud-Telme ◽  
Katia Ruel
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Significant Proportion ◽  
Pulp Fibers ◽  
Chemical Pulp ◽  
Recycled Pulp ◽  
Transmission Electron ◽  
Large Heterogeneity ◽  
Recycled Fibers ◽  
Packaging Paper

Abstract Transmission electron microscopy was used to investigate the ultrastructure of recycled pulp fibers originating from a household collection plant and intended for the production of packaging paper. Three recovered paper grades and recycling processes, including pulping, screening, cleaning and refining, were assessed with emphasis on surface and internal fibrillation as well as xylan localization. Results showed a large heterogeneity with respect to fiber ultrastructure within and between the grades. Screening and cleaning steps had no detectable effects, but refining clearly increased cell-wall delamination and surface fibrillation. Immunolabeling of xylans showed that they were distributed rather evenly across the cell walls. They were also present on fines. Two different mechanisms for fiber delamination and surface fibrillation were found, one which implies that internal and external fibrillation take place simultaneously across the cell wall, and another which implies successive peeling of layers or sub-layers from the outside towards the inside. It is suggested that recycled fibers of chemical pulp origin undergo the former mechanism and recycled fibers that contain lignin binding the cell wall matrix give rise to the latter peeling mechanism. Because several recycled fibers were severely delaminated and almost fractured, we suggest that to produce a good packaging paper, it is important that recycled pulp should contain a significant proportion of fibers with high intrinsic strength.

Effect of Wood Pulp Fibre Concentration on Gas Hold-up in Bubble Columns

1993 ◽  
Vol 65 (3) ◽  
pp. 306-308 ◽  
Author(s):  
Jerôme Went ◽  
Mohamad Jamialahmadi ◽  
Hans Müller-Steinhagen
Keyword(s):  
Wood Pulp ◽  
Bubble Columns ◽  
Pulp Fibre ◽  
Fibre Concentration ◽  
Wood Pulp Fibre

Physical Simulation of Weldability of Weldox 1300 Steel

2013 ◽  
Vol 762 ◽  
pp. 551-555 ◽  
Author(s):  
Marek Stanislaw Węglowski ◽  
Marian Zeman ◽  
Miroslaw Lomozik
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Physical Simulation ◽  
High Strength ◽  
Parent Material ◽  
Cooling Time ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Transformation Diagrams ◽  
The Impact

In the present study, the investigation of weldability of new ultra-high strength - Weldox 1300 steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on the microstructure and mechanical properties of the heat affected zone (HAZ). In the frame of these investigation the microstructure was studied by the light (LM) and transmission electron microscopies (TEM). It has been shown that the microstructure of the Weldox 1300 steel is composed of tempered martensite, and inside the laths the minor precipitations mainly V(CN) and molybdenum carbide Mo2C were observed. Mechanical properties of parent material were analysed by the tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 - 300 s. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The results show that the impact toughness and hardness decrease with the increase of t8/5 under the condition of a single thermal cycle in simulated HAZ. The continuous cooling transformation diagrams (CCT-W for welding conditions) of Weldox 1300 steel for welding purposes was also elaborated. The steel Weldox 1300 for cooling time in the range of 2,5 - 4 s showed martensite microstructure, for time from 4 s to 60 s mixture of martensite and bainite, and for longer cooling time mixture of ferrite, bainite and martensite. The results indicated that the weldability of Weldox 1300 steel is limited and to avoid the cold cracking the preheating procedure or medium net linear heat input should be used.

scholarly journals Multi-Scale Investigation of Body-Glaze Interface in Ancient Ceramics

Heritage ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 2480-2494 ◽  
Author(s):  
Marie Godet ◽  
Gauthier Roisine ◽  
Emmie Beauvoit ◽  
Daniel Caurant ◽  
Odile Majérus ◽  
...  
Keyword(s):  
Single Crystals ◽  
The Body ◽  
Firing Time ◽  
Body System ◽  
Slow Cooling ◽  
French Renaissance ◽  
Electron Microscopies ◽  
Multi Scale ◽  
Continuous Layer ◽  
Transmission Electron

Bernard Palissy is a French Renaissance ceramist renowned for his masterpieces called Rustiques Figulines on which dozens of glazes of different chemistries (and thus firing behaviors) coexist harmoniously. This study aims at gathering information on the master procedure -never revealed- by investigating the body-glaze interface region (focusing on iron-colored honey transparent glaze-white body system). Optical and electron microscopies including transmission electron microscopy (TEM) are used to characterize the micro and nanostructure of both archaeological and replicas interfaces elaborated in controlled conditions (firing time, cooling rate, addition of Al in the glazing mixture). Both types of interfaces are comparable: a modified paste area from which are growing a relatively continuous layer of interfacial crystals identified as lead feldspars (K,Ca)PbAl2Si2O8 micro-sized single-crystals incorporating mullite 3Al2O3.2SiO2 nano-sized single-crystals. Modification of the firing parameters and removal of Al from the glazing mixture change essentially the interface extension and the micro-crystals morphology. By comparing archaeological and replica interfaces and considering previous studies, we can now state that Palissy was very likely adding clay (Al) in his frit. Moreover, he was probably working with a firing time of more than 1 h followed by slow cooling in the oven.

Dual Beam Focused Ion Beam and Transmission Electron Microscopies of Nanoscale Sectioned Diatom Frustules

2007 ◽  
Vol 13 (S02) ◽  
Author(s):  
T Gutu ◽  
J Wu ◽  
C Jeffreys ◽  
C-H Chang ◽  
G Rorrer ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Electron Microscopies ◽  
Dual Beam ◽  
Transmission Electron

scholarly journals Sedimentation Method to Evaluate PFI Mill Beating Degree of Wood Pulp Fibers

2004 ◽  
Vol 60 (4) ◽  
pp. 112-117 ◽  
Author(s):  
Bo Chen ◽  
Daisuke Tatsumi ◽  
Takayoshi Matsumoto
Keyword(s):  
Wood Pulp ◽  
Pulp Fibers ◽  
Sedimentation Method
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