Influence of hemicellulose content of Eucalyptus and Pinus fibers on the grinding process for obtaining cellulose micro/nanofibrils

Holzforschung ◽  
2019 ◽  
Vol 73 (11) ◽  
pp. 1035-1046 ◽  
Author(s):  
Matheus Cordazzo Dias ◽  
Maressa Carvalho Mendonça ◽  
Renato A.P. Damásio ◽  
Uasmim Lira Zidanes ◽  
Fábio Akira Mori ◽  
...  
Keyword(s):  
Energy Savings ◽  
Alkali Concentration ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
Partial Removal ◽  
Hemicellulose Content ◽  
Hemicellulose Removal ◽  
Pre Treatment ◽  
Mechanical Fibrillation ◽  
Determining Factor

Abstract The objective of this study was to verify the effect of the hemicellulose content of commercial bleached pulps on the ease of mechanical fibrillation and on its energy consumption (EC). NaOH in concentrations of 5% with 2 h of reaction, and 10% with 1 and 2 h of reaction, was evaluated for the partial removal of hemicelluloses. Pulp fibrillation was influenced by hemicellulose removal, being less fibrillated when excessive removal occurred (in the range of 4–8.5%). Hemicellulose content in the range of 9–13% increased the water retention value (WRV) and led to nanofibrils with smaller diameter, while a stronger alkali concentration reduced the WRV. X-ray diffraction (XRD) showed that reaction time was a determining factor for the crystallinity of the samples and partial conversion of cellulose I to cellulose II in pretreatments with NaOH 10% (1 and 2 h), and was a factor that may also damage the fibrillation process. Pre-treatment with NaOH 5% for 2 h promoted energy savings for both pulps. This work demonstrated that hemicellulose content has a considerable influence on the mechanical fibrillation and is a key aspect of the balance between efficient fibrillation and the energy required for that.

scholarly journals Leaching Titaniferous Magnetite Concentrate by Alkaline Aqueous Solution

2021 ◽  
Author(s):  
Ke Guo ◽  
Shaoyan Wang ◽  
Renfeng Song ◽  
Zhiqiang Zhang
Keyword(s):  
Aqueous Solution ◽  
Alkali Concentration ◽  
Water Usage ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Iron Concentrate ◽  
Titaniferous Magnetite ◽  
Magnetite Concentrate ◽  
Kinetics Of

AbstractLeaching titaniferous magnetite concentrate with alkali solution of high concentration under high temperature and high pressure was utilized to improve the grade of iron in iron concentrate and the grade of TiO2 in titanium tailings. The titaniferous magnetite concentrate in use contained 12.67% TiO2 and 54.01% Fe. The thermodynamics of the possible reactions and the kinetics of leaching process were analyzed. It was found that decomposing FeTiO3 with NaOH aqueous solution could be carried out spontaneously and the reaction rate was mainly controlled by internal diffusion. The effects of water usage, alkali concentration, reaction time, and temperature on the leaching procedure were inspected, and the products were characterized by X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy, respectively. After NaOH leaching and magnetic separation, the concentrate, with Fe purity of 65.98% and Fe recovery of 82.46%, and the tailings, with TiO2 purity of 32.09% and TiO2 recovery of 80.79%, were obtained, respectively.

Influence of High Current Pulsed Electron Beam Irradiation on Ni-P Electroless Plating

2011 ◽  
Vol 299-300 ◽  
pp. 77-81
Author(s):  
Yang Xu ◽  
Sheng Zhi Hao ◽  
Xiang Dong Zhang ◽  
Min Cai Li ◽  
Chuang Dong
Keyword(s):  
Electroless Plating ◽  
Electron Beam Irradiation ◽  
Xrd Analysis ◽  
High Current ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pulsed Electron Beam ◽  
6063 Aluminum Alloy ◽  
Pre Treatment ◽  
Better Than

The surface irradiation of 6063 aluminum alloy by high current pulsed electron was conducted with the aim of replacing the complicated pre-treatment in the processes of electroless plating. To explore the microstructure changes, optical metallography, SEM (scanning electron microscope), XRD (X-ray diffraction) analyses were carried out, and the sliding tests were used for the detection of wear resistance. It was concluded that the HCPEB irradiation could replace the pre-treatment of aluminum substrate as required in conventional electroless plating with a decreased surface roughness of Ni-P alloy plating layer. The plates exhibited an amorphous microstructure as demonstrated by XRD analysis. The plates, produced with the routine of HCPEB irradiation, activation and electroless plating possess, also exhibited good quality, even better than that of conventional electroless plating technique.

scholarly journals OPTICAL PROPERTIES ON Li2O-K2O-WO3-B2O3 GLASS SYSTEM

2013 ◽  
Vol 22 ◽  
pp. 278-283
Author(s):  
A. EDUKONDALU ◽  
M. A. SAMEE ◽  
SHAIKH KAREEM AHMMAD ◽  
SAIR MD. TAQIULLAH ◽  
SYED RAHMAN ◽  
...  
Keyword(s):  
Glass Structure ◽  
Glass System ◽  
Alkali Concentration ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Mixed Alkali ◽  
Absorption Studies ◽  
Mixed Alkali Effect ◽  
Oxide Ion ◽  
B2o3 Glass

Mixed alkali tungsten borate glasses xLi2O–(30–x) K2O–10WO3–60B2O3 (0 < x < 30) were prepared from the melts. These glasses were characterized using X-ray diffraction, differential scanning calorimetry and density measurements. Optical absorption studies were carried out as a function of alkali content to look for mixed alkali effect (MAE) on the spectral properties of these glasses. From the study of ultraviolet absorption edge, the optical band gap energies and Urbach energies were evaluated. The average electronic polarizability of the oxide ion, optical basicity and the interaction parameters were also evaluated for all the glasses. Many of these parameters vary non-linearly exhibiting a minima or maxima with increasing alkali concentration, indicating the mixed alkali effect. An attempt is made to interpret MAE in this glass system in terms of its glass structure.

Surface analytical study of uranium exposed to low pressures of hydrogen at ∼ 80°C

2012 ◽  
Vol 1444 ◽  
Author(s):  
Robert M. Harker ◽  
Afiya H. Chohollo
Keyword(s):  
Room Temperature ◽  
Analytical Study ◽  
Treatment Cycle ◽  
X Ray Diffraction ◽  
Standard Samples ◽  
X Ray ◽  
Surface Precipitation ◽  
Pre Treatment ◽  
Low Pressures ◽  
Scanning Electron

ABSTRACTIdentical samples of uranium coupons were prepared and each exposed to hydrogen for different times (where this time is significantly less than a classically understood ‘induction time’). Samples were prepared from rolled depleted uranium stock: as-received oxide was removed on all surfaces and two faces (~12x12 mm) were polished to a sub-micron standard. Samples were individually taken through a Vacuum Thermal Pre-Treatment cycle from room temperature to 200°C to the reaction temperature (80°C) over 40 hours and subsequently exposed to 10 mbar O2 for 24 hours. After O2 was removed, the samples were exposed to hydrogen for pre-determined times of up to 48 minutes. Examination of the samples by Scanning Electron Microscopy (SEM) has, as expected, identified small features protruding from the surface believed to have been caused by sub-surface precipitation of UH3. In general these features are circular and isolated from each other, have a diameter of less than 3μm and appear as either ‘flat-topped’ or ‘domed’ morphology. In addition, longer time exposure samples show a predominance of ‘area attack’ where coalesced sub-surface precipitation appears to be confined to particular metal grains. X-Ray Diffraction (XRD) data show an increase in the quantity of UH3 with time.

Effects of cultivation, washing, and bleaching conditions on bacterial cellulose fabric production

2018 ◽  
Vol 89 (6) ◽  
pp. 1094-1104 ◽  
Author(s):  
Juyeon Han ◽  
Euijin Shim ◽  
Hye Rim Kim
Keyword(s):  
Bacterial Cellulose ◽  
Textile Industry ◽  
Control Sample ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
Naoh Solution ◽  
New Type ◽  
The Fourier Transform ◽  
Bleaching Step ◽  
Fabric Production

This study aims to compare different conditions in the three-step (cultivation, washing, and bleaching) production of white bacterial cellulose (BC) fabric to introduce it as a new type of fabric in the textile industry. The BC fabric was evaluated on the basis of its surface morphology and chemical structure. The “production BC” after the cultivation step was cultured using glucose as the carbon source in the Hestrin–Schramm (HS) medium. It was produced with the highest production yield (33.2 ± 6.85%), the highest thickness (0.35 ± 0.09 mm), and the flattest surface (211 nm). The bacteria remaining on “washed BC” after the washing step were washed out using 3% NaOH solution, and the nanoscale network structure maintained its integrity after washing. The white BC fabric after the bleaching step was bleached using 5% H2O2 solution. The white BC fabric with the highest white index (73.15 ± 1.09%) without a natural yellowish-brown color was produced. In the Fourier transform infrared spectroscopy (FTIR) spectra of the white BC fabric, the peaks of proteins and amino acids derived from the bacteria disappeared, while the cellulose I crystal structure was maintained. Also, X-ray diffraction analysis showed that the crystallinity of the white BC fabric increased compared to that of the control sample, and the highest crystallinity of 80.6% was obtained.

Photocatalytically Active Cotton Fabrics Produced with Anatase Synthesized Using a Low-Temperature Sol-Gel Process

2018 ◽  
Vol 762 ◽  
pp. 408-412
Author(s):  
Raivis Eglītis ◽  
Gundars Mežinskis
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
Anatase Nanoparticles ◽  
Pre Treatment

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.

Comparative Analysis of Crystallinity Changes in Cellulose I Polymers Using ATR-FTIR, X-ray Diffraction, and Carbohydrate-Binding Module Probes

2011 ◽  
Vol 12 (11) ◽  
pp. 4121-4126 ◽  
Author(s):  
Alenka Kljun ◽  
Thomas A. S. Benians ◽  
Florence Goubet ◽  
Frank Meulewaeter ◽  
J. Paul Knox ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Carbohydrate Binding ◽  
Carbohydrate Binding Module ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
X Ray ◽  
Crystallinity Changes

Converse Piezoelectric Effect in Cellulose I Revealed by Wide-Angle X-ray Diffraction

2010 ◽  
Vol 11 (5) ◽  
pp. 1281-1285 ◽  
Author(s):  
Wolfgang Gindl ◽  
Gerhard Emsenhuber ◽  
Johannes Plackner ◽  
Johannes Konnerth ◽  
Jozef Keckes
Keyword(s):  
Piezoelectric Effect ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
X Ray ◽  
Converse Piezoelectric Effect

scholarly journals Platinum Group Elements Recovery from Used Catalytic Converters by Acidic Fusion and Leaching

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 485 ◽  
Author(s):  
Erik Prasetyo ◽  
Corby Anderson
Keyword(s):  
Platinum Group Elements ◽  
Raw Material ◽  
Catalytic Converters ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Chloro Complexes ◽  
Soluble Species ◽  
Platinum Group ◽  
Pre Treatment ◽  
Hcl Concentration

The recovery of platinum group elements (PGE (platinum group element coating); Pd, Pt, and Rh) from used catalytic converters, using low energy and fewer chemicals, was developed using potassium bisulfate fusion pretreatment, and subsequently leached using hydrochloric acid. In the fusion pre-treatment, potassium bisulfate alone (without the addition of an oxidant) proved to be an effective and selective fusing agent. It altered PGE into a more soluble species and did not react with the cordierite support, based on X-Ray Diffraction (XRD) and metallographic characterization results. The fusion efficacy was due to the transformation of bisulfate into pyrosulfate, which is capable of oxidizing PGE. However, the introduction of potassium through the fusing agent proved to be detrimental, in general, since potassium formed insoluble potassium PGE chloro-complexes during leaching (decreasing the recovery) and required higher HCl concentration and a higher leaching temperature to restore the solubility. Optimization on the fusion and leaching parameter resulted in 106% ± 1.7%, 93.3% ± 0.6%, and 94.3% ± 3.9% recovery for Pd, Pt, and Rh, respectively. These results were achieved at fusion conditions: temperature 550 °C, potassium bisulfate/raw material mass ratio 2.5, and fusion time within 30 min. The leaching conditions were: HCl concentration 5 M, temperature 80 °C, and time within 20 min.

scholarly journals Methods Comparison for the Synthesis of Deca-Dodecasil 3 Rhombohedral (DDR3) Zeolite Crystals

2015 ◽  
Vol 773-774 ◽  
pp. 1096-1100 ◽  
Author(s):  
Muhammad Mubashir ◽  
Yin Fong Yeong ◽  
Lau Kok Keong ◽  
Azmi bin Mohd Shariff
Keyword(s):  
Room Temperature ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Synthesis Conditions ◽  
Silica Source ◽  
Pre Treatment ◽  
Favorable Conditions ◽  
Scanning Electron ◽  
Zeolite Crystals

In the present work, DDR3 zeolite crystals were synthesized using two different methods. The silica sources used to synthesize DDR3 crystals were tetramethoxysilane (TMOS) and Ludox-40. The resultant samples were characterized using X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM). The XRD results showed that the peaks representing DDR3 structure were not obtained for the sample synthesized in 5 days at room temperature with ultrasonic pre-treatment of 3h using Ludox-40 as silica source. On the other hand, the XRD pattern obtained for the sample synthesized in 25 days at 160 o C using TMOS as a silica source were similar with the XRD peaks reported in the literature. From these results, it can be concluded that the synthesis conditions of 25 days at 160 o C using TMOS as silica source were the favorable conditions in obtaining DDR3 crystal structure.

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