scholarly journals Nanocellulose Production Using Ionic Liquids with Enzymatic Pretreatment

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3264
Author(s):  
Marta Babicka ◽  
Magdalena Woźniak ◽  
Kinga Szentner ◽  
Monika Bartkowiak ◽  
Barbara Peplińska ◽  
...  
Keyword(s):  
Particle Size ◽  
Ionic Liquids ◽  
Cellulose Ii ◽  
X Ray Diffraction ◽  
Enzymatic Pretreatment ◽  
Step Process ◽  
X Ray ◽  
The Past ◽  
Spherical Structure ◽  
Enzyme Pretreatment

Nanocellulose has gained increasing attention during the past decade, which is related to its unique properties and wide application. In this paper, nanocellulose samples were produced via hydrolysis with ionic liquids (1-ethyl-3-methylimidazole acetate (EmimOAc) and 1-allyl-3-methylimidazolium chloride (AmimCl)) from microcrystalline celluloses (Avicel and Whatman) subjected to enzymatic pretreatment. The obtained material was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), and thermogravimetric analysis (TG). The results showed that the nanocellulose had a regular and spherical structure with diameters of 30–40 nm and exhibited lower crystallinity and thermal stability than the material obtained after hydrolysis with Trichoderma reesei enzymes. However, the enzyme-pretreated Avicel had a particle size of about 200 nm and a cellulose II structure. A two-step process involving enzyme pretreatment and hydrolysis with ionic liquids resulted in the production of nanocellulose. Moreover, the particle size of nanocellulose and its structure depend on the ionic liquid used.

Preparation of nanocellulose by hydrolysis with ionic liquids and two-step hydrolysis with ionic liquids and enzymes

2021 ◽  
Vol 116 ◽  
pp. 5-14
Author(s):  
Marta Babicka ◽  
Magdalena Woźniak ◽  
Kinga Szentner ◽  
Sławomir Borysiak ◽  
Krzysztof Dwiecki ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Degree Of Crystallinity ◽  
Cellulolytic Enzyme ◽  
X Ray Diffraction ◽  
Production Methods ◽  
Step Process ◽  
X Ray ◽  
One Step ◽  
Xrd Patterns ◽  
The One

The aim of this study was to compare parameters of nanocellulose obtained by two different procedures: hydrolysis with ionic liquids (1-allyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate) and hydrolysis with ionic liquids in combination with hydrolysis using a cellulolytic enzyme from Trichoderma reesei. Avicel cellulose was treated with two ionic liquids: 1-allyl-3-methylimidazolium chloride (AmimCl) and 1-ethyl 3-methylimidazolium acetate (EmimOAc). In the two-step hydrolysis cellulose after treatment with ionic liquids was additionally hydrolyzed with a solution of enzymes. In order to characterize the obtained material, the following analyses were used: infrared spectroscopy, X-ray diffraction and dynamic light scattering. The results indicated that cellulose obtained by two-step nanocellulose production methods (first hydrolysis with ionic liquids and then with enzymes) showed similar parameters (particle size, XRD patterns and degree of crystallinity) as the material after the one-step process, i.e. hydrolysis with ionic liquids.

scholarly journals Chemistry and Bioactivity of NeoMTA Plus™ versus MTA Angelus® Root Repair Materials

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Sawsan T. Abu Zeid ◽  
Najlaa M. Alamoudi ◽  
Monazah G. Khafagi ◽  
Ensanya A. Abou Neel
Keyword(s):  
Particle Size ◽  
Apatite Formation ◽  
X Ray Diffraction ◽  
Large Particle Size ◽  
Globular Structure ◽  
X Ray ◽  
Spherical Structure ◽  
Root Repair ◽  
Repair Materials ◽  
High Aluminium

Objectives. To analyse the chemistry and bioactivity of NeoMTA Plus in comparison with the conventional root repair materials. Method and Materials. Unhydrated and hydrated (initial and final sets) materials were analysed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). For bioactivity study, small holes of dentin discs were filled with either materials, immersed in PBS for 15 days, and analysed with FTIR and scanning electron microscope with energy dispersive X-ray (SEM/EDX). The calculation of crystallinity and carbonate/phosphate (CO3/PO4) ratio of surface precipitates (from FTIR) and calcium/phosphate (Ca/P) ratio (from EDX) was statistically analysed using t-test or ANOVA, respectively, at 0.05 significance. Results. Both materials are tricalcium silicate-based that finally react to be calcium silicate hydrate. NeoMTA Plus has relatively high aluminium and sulfur content, with tantalum oxide as an opacifier instead of zirconium oxide in MTA Angelus. NeoMTA Plus showed better apatite formation, higher crystallinity and Ca/P but lower CO3/PO4 ratio than MTA Angelus. SEM showed globular structure with a small particle size in NeoMTA Plus while spherical structure with large particle size in MTA Angelus. Conclusion. Due to fast setting, higher crystallinity, and better bioactivity of NeoMTA Plus, it can be used as a pulp and root repair material.

Quantitative determination of goethite and hematite in kaolinitic soils by X-ray diffraction

Clay Minerals ◽  
1982 ◽  
Vol 17 (3) ◽  
pp. 359-363 ◽  
Author(s):  
N. Kämpf ◽  
N. Schwertmann
Keyword(s):  
Particle Size ◽  
Quantitative Estimate ◽  
Limit Of Detection ◽  
Quantitative Estimation ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Past ◽  
Fe Oxides ◽  
Two Factors

In the past, two factors have impeded the quantitative estimate of Fe-oxides in soils by X-ray diffraction. First, Fe-oxides are still quite often considered X-ray amorphous, although numerous results, e.g. a low ratio of oxalate- to dithionite-soluble Fe, have indicated the opposite. Second, even if crystalline, the cocentration of Fe-oxides in many soils is low, thereby complicating their identification by XRD. Recently, however, more sensitive methods such as Mössbauer spectroscopy and Differential-XRD (Schulze, 1981) have been introduced, which substantially reduce the lower limit of detection. Because these two methods are not generally available and, especially in the case of M&oum;ssbauer spectroscopy, are rather time consuming, ordinary XRD should be adapted for quantitative estimation of Fe-oxides.Determination can be facilitated by using samples in which the Fe-oxides are concentrated by particle-size separation and a 5 M NaOH boiling treatment (Norrish & Taylor, 1961). The latter treatment is particularly suitable for kaolinitic soils as the Fe-oxides are unaffected―provided certain precautions are taken (Käimpf & Schwertmann, 1982a). This paper gives details of a procedure for the quantitative estimation of goethite (Gt) and hematite (Hm) by XRD.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

scholarly journals Mining Wastes of an Albite Deposit as Raw Materials for Vitrified Mullite Ceramics

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 232
Author(s):  
Pedro J. Sánchez-Soto ◽  
Eduardo Garzón ◽  
Luis Pérez-Villarejo ◽  
George N. Angelopoulos ◽  
Dolores Eliche-Quesada
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Phase Evolution ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Mining Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value

In this work, an examination of mining wastes of an albite deposit in south Spain was carried out using X-ray Fluorescence (XRF), X-ray diffraction (XRD), particle size analysis, thermo-dilatometry and Differential Thermal Analysis (DTA) and Thermogravimetric (TG) analysis, followed by the determination of the main ceramic properties. The albite content in two selected samples was high (65–40 wt. %), accompanied by quartz (25–40 wt. %) and other minor minerals identified by XRD, mainly kaolinite, in agreement with the high content of silica and alumina determined by XRF. The content of Na2O was in the range 5.44–3.09 wt. %, being associated with albite. The iron content was very low (<0.75 wt. %). The kaolinite content in the waste was estimated from ~8 to 32 wt. %. The particle size analysis indicated values of 11–31 wt. % of particles <63 µm. The ceramic properties of fired samples (1000–1350 °C) showed progressive shrinkage by the thermal effect, with water absorption and open porosity almost at zero at 1200–1250 °C. At 1200 °C, the bulk density reached a maximum value of 2.38 g/cm3. An abrupt change in the phase evolution by XRD was found from 1150 to 1200 °C, with the disappearance of albite by melting in accordance with the predictions of the phase diagram SiO2-Al2O3-Na2O and the system albite-quartz. These fired materials contained as main crystalline phases quartz and mullite. Quartz was present in the raw samples and mullite was formed by decomposition of kaolinite. The observation of mullite forming needle-shape crystals was revealed by Scanning Electron Microscopy (SEM). The formation of fully densified and vitrified mullite materials by firing treatments was demonstrated.

scholarly journals Synthesis of magnesium carbonate hydrate from natural talc

2020 ◽  
Vol 18 (1) ◽  
pp. 951-961
Author(s):  
Qiuju Chen ◽  
Tao Hui ◽  
Hongjuan Sun ◽  
Tongjiang Peng ◽  
Wenjin Ding
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Crystal Growth ◽  
Crystal Morphology ◽  
Magnesium Carbonate ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
Morphological Transformation ◽  
X Ray ◽  
Carbonation Process

AbstractVarious morphologies of magnesium carbonate hydrate had been synthesized without using any organic additives by carefully adjusting the reaction temperature and time during the talc carbonation process. At lower temperatures, magnesium carbonate hydrate was prone to display needle-like morphology. With the further increase of the carbonation temperature, the sheet-like crystallites became the preferred morphology, and at higher aging temperatures, these crystallites tended to assemble into layer-like structures with diverse morphologies, such as rose-like particles and nest-like structure. The reaction time had no effect on the crystal morphology, but it affected the particle size and situation of the crystal growth. X-Ray diffraction results showed that these various morphologies were closely related to their crystal structure and compositions. The needle-like magnesium carbonate hydrate had a formula of MgCO3·3H2O, whereas with the morphological transformation from needle-like to sheet-like, rose-like, and nest-like structure, their corresponding compositions also changed from MgCO3·3H2O to 4MgCO3·Mg(OH)2·8H2O, 4MgCO3·Mg(OH)2·5H2O, and 4MgCO3·Mg(OH)2·4H2O.

scholarly journals Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tropical Fruit ◽  
X Ray ◽  
Freeze Dried ◽  
Fruit Powder ◽  
Lcr Meter

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

Strain Measurement by X-ray Diffraction Methods

1949 ◽  
Vol 1 (3) ◽  
pp. 211-224
Author(s):  
G. B. Greenough
Keyword(s):  
Strain Measurement ◽  
Plastic Anisotropy ◽  
Stress And Strain ◽  
Routine Method ◽  
X Ray Diffraction ◽  
Strain Measurements ◽  
X Ray ◽  
The Past ◽  
Polycrystalline Metals ◽  
The Individual

SummaryMany papers have been written on the measurement of strain by X-ray diffraction methods and on the interpretation of these strains in terms of stresses. Whereas, during the past few years, the experimental methods of determining the strains have. remained largely unchanged, research has shown that the older techniques for calculating stresses from strains are not always valid.In this paper an attempt is made to describe some of the principles of strain measurement by X-ray diffraction methods to those who are unfamiliar with the methods. The types of stress and strain systems which may exist in polycrystalline metals are then considered, particular attention being paid to the effect of the elastic and plastic anisotropy of the individual crystals. Some indication is given as to how the earlier methods of interpreting X-ray strain measurements should be modified, but no rigid routine method is proposed for use in a general case.

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