2θ Range Research Articles

In English

The main idea of this work is the investigation of structural and morphological characteristics of microcrystalline cellulose with switchgrass (Panicum virgatum L.) by the method of organo-solvent cooking with the addition of various brands of ion-exchange resins instead of sulfuric acid. A sulfonated copolymer of styrene and divinyl benzene with two functional groups per ring - Purolite CT-275 and a sulfonated copolymer based on tetrafluoroethylene - Nafion NR-50 were chosen as initial ion exchange resins. Air-dry switchgrass (Panicum virgatum L.), a technical culture, was used for the research. Microcrystalline cellulose (MCC) was obtained from it by the method of organo-solvent cooking with the addition of a solid catalyst. Using the methods of XRD, FTIR-ATR, AFM, TGA and DSC, the structure and morphology of MCC were studied. It is found that the use of ion-exchange resins in the organo-solvent method of obtaining MCC in a batch reactor requires the use of protective covers for the catalyst to avoid its mechanical damage. It has been found that only sulfonated copolymers based on tetrafluoroethylene are stable in the cooking solution, in contrast to sulfonated copolymers of styrene and divinylbenzene, and allow obtaining MCC from millet with a yield of 53 % versus 40 % for the classical method and a degree of polymerization of 440 versus 578, respectively. Due to the destruction of amorphous binders in the MCC’s from switchgrass (Panicum virgatum L.), regardless of the conditions of its production, we observe further ordering of the structure of the obtained MCC which is expressed in narrower and more intense peaks in the range 2θ = 22–23°. The FTIR-ATR method showed that the obtained MCC has functional groups similar to commercial M-1021. The AFM method showed that MCC has a globular and wavy relief. Surface roughness with globular relief is 12.6 nm.

Optimization of enhanced collagen extraction from tannery rawhide trimming waste using pineapple peel-derived bromelain enzyme through response surface methodology

Plant-based enzymatic extraction of collagen from tannery rawhide trimmings can play an important role in the utilization of tannery solid waste, providing economically viable and sustainable solutions. This study employed bromelain enzyme derived from pineapple (Ananas comosus) peel waste for collagen extraction and compared the procedure with conventional acetic acid extraction. The recovery of bromelain enzyme at 30–70% ethanol precipitation exhibited a 2.21-fold purification and a 98% yield. Response surface methodology (RSM) analysis revealed that bromelain enzyme-extracted collagen (BEC) yielded 82.20% at a hydrolysis time of 18.39 h, a mixing ratio of 22.38, and a temperature of 39.32 °C. In contrast, a lower yield of 66.94% was observed in the case of acetic acid-extracted collagen (AEC) at a hydrolysis time of 18.66 h, a mixing ratio of 19.41, and a temperature of 27.09 °C. Fourier transform infrared spectroscopy (FTIR) confirmed the successful extraction of both AEC and BEC. Thermogravimetric analysis (TGA) indicated the higher thermal stability of BEC compared to AEC. X-ray Diffraction (XRD) displayed characteristic peaks of collagen in the range of 2θ of 15–25°, affirming that BEC (sharp peak at 19.49°) is more crystalline than AEC (broadening peak at 19.88°). Elemental analysis revealed a higher nitrogen content (6.78%) in BEC, indicating a higher protein content than that of AEC (6.31%). Furthermore, antimicrobial activity, cytotoxicity evaluation, and heavy metal analysis revealed the potential applications of collagen in cosmetics, biomaterials, and tissue engineering.

Effect of stabilizer content in different solvents on the synthesis of ZnO nanoparticles using the chemical precipitation method

Zinc Oxide (ZnO) nanoparticles (NPs) have been synthesized by a simple chemical precipitation method. The effect of monoethanolamine (MEA) content in different solvents on ZnO NPs synthesis and their structural properties has been investigated. The NPs synthesized by using isopropanol (IPA) with 15 ml MEA as a stabilizer under the most favorable conditions (deposition time, td = 120 min, temperature = 60 °C) showed good structural properties. Synthesized NPs exhibited beneficial structural properties after annealing. The hexagonal wurtzite crystal structure of ZnO NPs was verified by XRD. Different models were used to calculate structural parameters such as crystallite size, strain, stress, and energy density for all the reflection peaks of XRD corresponding to ZnO lying in the range 2θ = 15⁰–80⁰. The crystallite size of the ZnO nanoparticles was found to be 50–60 nm. FTIR and EDX confirmed the presence of ZnO NPs in the samples. SEM micrograph of all the samples revealed that the grain sizes decrease gradually with the increase of the amount of MEA. UV–Visible diffuse reflectance spectroscopy results provide evidence that the ZnO NPs possess broader absorption bands, together with high band gap energy. The ZnO NPs synthesized with IPA solvent have the highest transmittance and band gap energy of 3.3eV. According to DLS data, various content of MEA stabilizer in solvent affects the hydrodynamic size of ZnO NPs.

Chitosan-Based Gastric Dressing Materials Loaded with Pomegranate Peel as Bioactive Agents: Pharmacokinetics and Effects on Experimentally Induced Gastric Ulcers in Rabbits.

This study reported the fabrication and characterization of gastric dressing, composed of gelatine (GEL), chitosan (CH), and pomegranate peel (PP) extract. The structural changes occurring after γ-irradiation of GEL-CH-PP dressing were reported. The results showed that the electron paramagnetic resonance (EPR) spectroscopy of un-irradiated GEL-CH-PP showed two paramagnetic centers, which corresponded to g = 2.19 and g = 2.002. After irradiation, a new active centre appeared at g = 2.0035 at 10 kGy. The Fourier transform infrared spectroscopy (FTIR) analyses revealed an increase in peak intensity at C-H chains, as well as the C=O carboxyl groups at 10 kGy, due to the cross-linking phenomenon. The X-ray diffraction analysis showed a low change of crystallinity between the range of 2θ (15-30°). Moreover, γ-rays enhanced scavenging DPPH radical activity (51±%) and chelating power activities 79.12%. A significant inhibition of antibacterial and anti-biofilm activities (p < 0.01) was noticed. The hemolysis rates showed 0.42%, suggesting a high hemocompatibility, and exhibited significant anti-inflammatory activity in vitro (48%). In vivo, the healing effects of GEL-CH-PP dressing showed that the incidence and severity of gastric histopathological lesions decreased, compared with the ulcerated group, which could explain the bioavailability and the pharmacokinetic findings. The results highlight the loading of bioactive agents into polymer-based gastric dressings, with promising pharmacokinetics properties and effects on the induced ulcera in rabbits.

Composites cement/BaSO4/Fe3O4/CuO for improving X-ray absorption characteristics and structural properties

Composite cement/BaSO4/Fe3O4/CuO with a thickness of 0.6 cm for various amounts of CuO: 2 wt%, 4 wt%, 6 wt%, and 8 wt% were successfully synthesized for the X-ray radiation shield. The bonding characteristics of composite and structural properties were determined using Fourier transform infrared spectra for the wavelength range of 4000–400 cm−1 and X-ray diffraction with the range of 2θ from 25° to 50°, respectively. The shielding ability was measured using a mobile X-ray with an energy of 55, 66, and 77 keV for determining the mass and linear attenuation coefficient, electronic and atomic cross-section. These shield characteristics best agreement with theoretical calculation from the XCOM database for energy < 77 keV with half value layer (HVL) < 0.3 cm. The best shielding in this study indicated by the lowest HVL and MFP is composite for CuO 8 wt%. The HVL and MFP shows better values compared to the previous reported using composite rubber-based, indicated high potentials composite in this study for design new and efficient radiology rooms as an alternative concrete, especially for X-ray radiation, in the future.

Novel bioactive adhesive dressing based on gelatin/ chitosan cross-linked cactus mucilage for wound healing.

The development of natural-based wound dressings is of great interest in the field of skin tissue engineering. Herein, different bioactive molecules such as gelatin (GEL), chitosan (CH) and mucilage (MU) were used to prepare a wound dressing. The physico-chemical and biological characterizations occurring after γ-irradiation were investigated. Results showed that Electron Paramagnetic Resonance (EPR) spectroscopy of un-irradiated GEL-CH-MU biomaterial showed two paramagnetic centers which correspond to g = 1.89 and g = 2.033. A generated new active center appeared at g = 2.003 at 25 kGy due to the interactions of gamma rays with the polymer chain creating signals at the absorbing functional groups. X-ray diffraction (XRD) spectra preserved the semi-crystalline structures between a range of 2θ (5° and 45°). Fourier Transform Infrared spectroscopy (FTIR) revealed that the initiation of cross linking phenomena. Moreover, γ-rays significantly increased antioxidant activity (9.1 ± 0.07%, p < 0.05) and exhibited a high anti-inflammatory activity (70%) at 25 kGy. Significant antibacterial activities in vitro liquid medium was observed. In addition GEL-CH-MU dressing exhibited high hemocompatibility. Conducted investigations state that such innovative dressing natural-based polymers for advanced wound care may be considered as useful for biomedical purposes.

Influence of the composition of a boron-containing active medium in the form of a coating on the structure and properties of a diffusion layer on titanium parts

A comparative study of VT-1.0 titanium boriding, carboboronizing and borosiliconizing methods was carried out in order to increase wear resistance in aggressive environments at elevated temperatures. The microstructure of diffusion coatings was investigated, their thickness and microhardness were determined. Diffusion saturation of 10×10×25 mm VT-1.0 titanium samples was carried out from saturating coatings based on boron carbide. Process temperature of 950 °C, and saturation time of 1.5 h were used as saturation conditions. At the end of high-temperature exposure, samples were removed from the furnace and cooled in air to room temperature, cleaned from saturating coatings with wooden spatulas, and boiled in the soap and soda solution for 1 h. A continuous diffusion layer 80–100 μm thick forms on the titanium surface. The borosiliconized diffusion layer obtained by titanium saturation from the mixture of 45%B 4 C–5%Na 2 B 4 O 7 –22%Si–5%NaF–3%NaCl– 20%CrB 2 has a higher microhardness: 1520 HV 0.1 versus 1280 HV 0.1 for carboboride one and 1120 HV 0.1 for boride one. In this case, boride and carboboride coatings, obtained, respectively, by saturation from 45%B 4 C–5%Na 2 B 4 O 7 –5%NaF–25%Al 2 O 3 –20%CrB 2 and 70%B 4 C– 5%Na 2 B 4 O 7 –5%NaF–20%CrB 2 coatings have a pronounced zonal structure. The upper zone of these coatings having high microhardness also features high brittleness indicators, which makes it impossible to accurately measure microhardness distribution due to chipping and cracking at microhardness measurement points. The qualitative composition of coatings on titanium was studied by X-ray diffraction using the DRON-6 X-ray diffractometer in filtered CuK α radiation (λ = 1.5418 Å) in the angle range of 2θ = 20÷80°. The diffusion coating exhibits reflections of titanium carbide, chromium and titanium borides, and a certain amount of the Cr 2 Ti intermetallic compound. Boride phases of chromium and titanium refer to high boron phases with high specific boron content: TiB, CrB, Ti 2 B 5 , Ti 3 B 4 и Cr 2 B 3 .

SYNTHESIS, CHARACTERIZATION AND PROPERTIES OF PROCESSABLE POLYAZOMETHINES FOR HIGH TEMPERATURE APPLICATIONS

New dithiazole-diamine monomer containing cyclohexylidene ring and pendant methyl group i.e. 1,1-bis [4-(2- aminothiazole)-3-methyl phenyl] cyclohexane (BATMPC) was synthesized through various steps. The structure of new dithiazole amine monomer was confirmed by FT-IR, 1H NMR and 13CNMR Spectrometry. A series of polyazomethines containing cardo cyclohexane-thiazole unit have been incorporated by the polycondensation of a new diamine i.e. (BATMPC), with proportionate of aromatic dialdehydes. The impact of insertion of cardo cyclohexane, pendant methyl group and thiazole entity in the polyazomethine matrix with the dialdehydes [isophthalaldehyde (1,3 IPA) and terephthalaldehyde (1,4 TPA)], on solubility and thermal stability has been studied. All polyazomethines shown Tg in the range of 220-241ºC and T10% value of all thermally stable polyazomethines in nitrogen atmosphere was in between of 395-415ºC These polyazomethines exhibited solubility in various polar aprotic solvents such as NMP, DMSO, DMAc, DMF etc. However, these polyazomethines were insoluble in common solvents such as DCM and CHCl3. X-ray diffraction study confirms that all the polyazomethines are amorphous in nature having broad peak in the range of 2θ=20°. The UV absorption at 360 nm shows that there is a formation of imine (-C=N-) linkages in the polymer matrix which is helpful for the conduction of electron throughout. The structure-property correlation among these polyazomethines was studied, in view of their potential applications for high temperature applications.

Effect of ionic liquid on structural, thermal and electrical transport properties of PVA-PVP based polymer blend electrolyte membrane

The present paper deals with the loading effect of ionic liquid (IL), 1-ethyl-3-methylimidazolium methylsulfate [EMIM][MS] on structural and electrical transport properties of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG)- salt, sodium methyl sulfate (MeSO4Na) based polymer blend electrolyte (PBE) films. The samples were prepared using conventional solution cast method. The x-ray Diffraction (XRD) result shows that PBE films has characteristic peak with broad halo appeared in the range 2θ = 19.95° to 22.72° reveals the amorphous nature (semi-crystalline).The % degree of crystalinity (X c ) of prepared IL based PBE films were found to decreases with increasing IL content. Fourier transform infrared (FTIR) in total attenuated reflectance (ATR) mode analysis reveals the interaction between the functional groups (C=O and O–H) of polymer electrolyte with the cation, EMIM+/anion of IL/salt. Thermogravimetric analysis (TGA) shows that IL based PBE samples decomposes in multistep and Td,onset/peak value decreases with IL loading. Sample containing 30 wt%IL shows optimum dc conductivity value ∼1.5 × 10−4 S cm−1 at 30 °C with minimum activation energy ∼0.21 eV. Logσ versus 1000/T plot for all PBE sample follow the Arrhenius type thermally activated process and activation energy decreased with increasing IL content in PBE films. Frequency dependent conductivity behavior for IL based PBE film follow the Jonscher’s power law with power law exponent, n value<1 (amorphous polymeric system). AC conductivity spectra and loss tangent spectra (tanδ) with respect to IL/temperature content scalled successfully. Dielectric relaxation behavior and conductivity relaxation were analyses with respect to IL content and temperature. Mobility, total number of charge/ion density, ion diffusivity was estimated. Ionic transference number (ITN) measurement (tion ∼0.98, tele ∼0.02) reveals that ions are principal charge carriers in present system. Linear sweep voltametry (LSV) and cyclic voltamerty (CV) measurements show that 30 wt%IL containing sample has electrochemical stability window (ESW) ∼±2.7volt and Faradic oxidation reduction peaks were observed, respectively.

Вплив борошна з макухи олійних культур на вміст цукрів у житньому хлібі

Subject of research – sugar content in rye bread with fractionally defatted flour from walnuts, pumpkin seeds, sesame and Jerusalem artichoke powder. The purpose – to investigate the chemical composition of sugars in flour from oilseed meal and to explain the impact of new raw materials upon the sugar content in bread made from rye flour. Materials and methods. For the production of pilot of bread used: rye flour; fermented rye malt; table salt; drinking water; ready liquid rye sourdough (composition: Lactobacillus plantarum 30, L .casei 26, L. fermenti 34, L .brevis and Saccharomyces minor "Chernorichenskaya", S. cerevisiae L1); fractionally defatted flour from walnuts, pumpkin seeds and sesame produced by PE "Research and Production Company "Elitfito"; Jerusalem artichoke powder "Dar". The dough was prepared in a three-phase way: liquid sourdough – saccharified choux – dough. Jerusalem artichoke powder and oilseed meal were added to the dough. The chemical composition of sugars in raw materials and bread was determined by high-performance liquid chromatography. The effect of fractionally defatted flour on the course of processes in rye dough was performed on a farinograph and amylograph of Brabender. The intensity of gas formation of the dough was determined on the device AG-1. Changes in the crystal structure of the bread crumb were performed using X-ray phase analysis on the device DRON UM-1 in the range of angles 2θ from 5 to 60 degrees. Results. It is established that the share of sugars in flour from oilseed meal is 2 ... 8 times higher than the content of sugars in rye flour. The content of sugars in fractionally defatted flour from walnuts is 43.0 %, from pumpkin seeds – 14.2 %, from sesame – 12.8% by weight of dry matter. Up to 80% of all sugars in fractionally defatted flour are sucrose and maltose. The ratio of fructose to glucose in fractionally defatted flour from walnuts is 1:1.25; from pumpkin seeds – 1:0.73; of sesame seeds – 1:0.5. The addition of 7.0 % fractionally defatted flour mixed with 3 % of the Jerusalem artichoke powder reduces the mass fraction of sugars in bread compared to the bread made with Jerusalem artichoke only. It has been studied that fractionally defatted flour from walnuts, pumpkin seeds and sesame reduces the hydrolytic decomposition of rye flour starch and promotes the process of fermentation of sugars. Scope. A mixture of fractionally defatted flour from oilseed meal in the amount of 7 % should be used for the production of bread from rye flour with 3 % Jerusalem artichoke powder to the mass fraction of flour to reduce the content of high glycemic starch sugars.

GLAS FORMATION IN QUASI-TERNARY SYSTEMS AІ2S–ВIVS2–P2S5 (АI – Cu, Ag; ВIV – Ge, Sn)

The boundaries of the glass formation areas of quasiternary systems AІ2S–ВIVS2–P2S5 (АI – Cu, Ag; ВIV – Ge, Sn) have been established by the method of X-ray phase analysis. The compound GеS2 can exist in a glass state, so that germanium disulphide acts as a glass former in quasi-triple systems.The glass semiconductor alloys have been synthesized by the single-temperature method from the elementary substances of copper (99.99 wt.%), silver (99.99 wt.%), germanium (99.9999 wt.%), tin (99.999 wt.%), red phosphorus (99.998 wt.%) and sulfur (purity 99.997 wt.%). Maximum synthesis temperature was 1173 K, followed by quenching of the ampoules in a saturated solution of sodium chloride with crushed ice. Glasses with a high content of phosphorus are easily hydrolyzed under the influence of moisture of the air.Diffractograms have been recorded on a diffractometer DRON 4-13, CuKα-radiation, range of angles 2θ=10÷50°, stepped scan 0,05º, exposure time 2 seconds. Amorphousness of the obtained alloys has been controlled visually by the fracture characteristic of the glass and with the help of X-ray diffraction studies. «Gallo» has been observed on all diffractograms of glass samples, presence of which indicates the absence of long-range order in the alloy structure.There are continuous bands of glass formation on the sides GeS2–P2S5 in the studied germanium-containing systems АI2S–GеS2–P2S5. The obtained glasses have been transparent, yellow-red color with the fracture characteristic of the glass. The main factor is the tendency of GeS2 and P2S5 to the glass formation. There has been found that all samples have polycrystalline nature in the system Cu2S–GеS2. Only GeS2 and Ag2GeS3 have been obtained in the vitreous state from the cross section Ag2S–GeS2.The maximum content of Cu2S and Ag2S, which are a part of the glass in systems Сu(Ag)2S–GеS2–P2S5, is 10 and 70 mol.% accordingly.The areas of glass formation have been much smaller compared to similar germanium-containing in the state-containing systems of the glassformation area, which is associated with the strengthening of the metal component of the chemical bond by changing GeS2 to SnS2.We observe only two areas of glass formation in quasi-triple systems Сu(Ag)2S–SnS2–P2S5 which are on the side SnS2–P2S5: one in the area 5–15 mol.% P2S5, including approximately 5 mol.% Cu2S та Ag2S, the other – 35–65 mol.% P2S5, the maximum content of Cu2S and Ag2S is 13 and 4 mol.%.

Preparation and characterization of titanium dioxide nanoparticles and in vitro investigation of their cytotoxicity and antibacterial activity against Staphylococcus aureus and Escherichia coli

Titanium dioxide nanoparticles (TiO2 NPs) are photo-active metallic nanoparticles becoming promising agents in modern biomedical applications. Herein, a novel process for the synthesis of TiO2 NPs with high stability was developed by a sol–gel process and to investigate their cytotoxicity and antibacterial activity. Numerous experiments have been performed to confirm the morphologies, compositions, and physicochemical properties of prepared TiO2 NPs, such as field emission scanning electron microscopy, dynamic light scattering, Zeta potential, Fourier transform infrared spectroscopy and X-ray diffraction. MTT assay was applied to assess the cytotoxicity of the prepared nanoparticles. The results indicate that the synthesized nanoparticles' diameter is about 68 nm and contains the anatase phase, in the range of 2θ from 25 to 80 °C. The hydrodynamic radius of nanoparticles is about 140.4 nm, and the zeta potential of nanoparticles is about −44.6 mV. The MTT results have not shown any toxicity; the antibacterial inhibitory effect of TiO2 NPs at 200 mg/mL concentrations exhibited superior antibacterial activity at 15.9 ± 0.1, 14.0 ± 0.1 against Staphylococcus aureus and Escherichia coli, respectively. In conclusion, colloidal solutions with high stability were successfully synthesized, contributing to decreased dimensions and increased antibacterial properties.

Analysis of the Effect of Transmembrane Pressure on the Change in the Structural and Transport Properties of Active and Drainage Layers of Composite Films UPM-50 and UPM-100

Results are presented from investigating active and drainage layers of composite films (membranes) UPM-50 and UPM-100 before and after exposure to transmembrane pressure by means of IR spectra of reflection, X-ray scattering, and raster electron microscopy. It is found that changes in the IR spectrum of the working sample are caused by the destruction of weak bonds of C=O···H–N amide fragments of the polysulfonamide film. A drop in (C=O) vibration frequency ν by Δν = 20 cm−1 indicates redistribution of the electron density between C=O-groups and benzene rings as a result of the inductive effect of coupling, which results in the formation of charged functional groups CO−. The presence of CO– groups fragments a new supramolecular structure whose stability due to the dipole–dipole interaction of carbonyl anions. X-ray scattering of the initial and working samples in the 10°–35° range of angles 2θ is determined by three intense reflections at angles 2θ ~ 17.23°, 22.24°, 25.41° from crystallographic planes ((010), (100), and (110)) corresponding to the crystalline structure of lavsan (polyethylene terephthalate). A comparative analysis of the reduced intensities of reflections from crystallographic planes (010), (100) and the sizes of lamellas indicates that transmembrane pressure initiates conformational rearrangement of crystallites with crystallographic axis b oriented parallel to the film plane.

Исследование структуры и технологических характеристик фармацевтических субстанций рабепразола натрия

The purpose of the study is the choice of the pharmaceutical substance rabeprazole sodium with the optimal structure and technological characteristics for the development of Rabeprazole tablets. Materials and methods. The study was conducted on samples of pharmaceutical substances rabeprazole sodium of two manufacturers Changzhou Koni Pharmaceutical Co. Ltd., China - RAB 20131102 Series (Sample 1) and Nosh Labs Pvt. Ltd., India - of RS 0280311 (sample 2) and RS 0120914 (sample 3). Microphotographs were obtained on a TM-1000 electron microscope, Hitachi. Powder X-ray diffraction patterns were obtained on a Bruker D8 Advance automatic X-ray diffractometer. To identify the crystalline phases, the PDF-2 Powder Diffractometry Database and the Cambridge Crystal Structural Database were used. The flowability of pharmaceutical substances was determined according to OFS 1.4.2.0016.15, the fractional composition was determined by sieve analysis; to evaluate compressibility, the Carr and Hausner indices were calculated. Results. Samples of rabeprazole sodium 1 and 2 are amorphous in nature and are characterized by the presence of two amorphous halo in the range of angles 2θ of 4-7 ° and 18-24 °. Sample 3 is probably a mixed version, in which an amorphous and crystalline component is presented. The studied samples differ in bulk density and fractional composition. Samples 2 and 3 are more uniform compared to sample 1, their bulk density is acceptable for the process. Conclusion. Pharmaceutical substance rabeprazole sodium of manufacturer Nosh Labs Pvt. Ltd. (India) has a more uniform fractional composition and acceptable bulk density. However, the processes used by this manufacturer do not exclude the formation in some cases of a crystalline component in a pharmaceutical substance, which can lead to a significant change in the physicochemical and mechanical characteristics of the pharmaceutical substance in different batches.

Synthesis of Si/Cu Amorphous Adsorbent for Efficient Removal of Methylene Blue Dye from Aqueous Media

In this paper, the gelation technique was utilized for the synthesis of a Si/Cu amorphous sample composed of oxygen, sodium, silicon, and copper. The obtained sample was identified utilizing FT-IR, EDS, XRD, and FE-SEM instruments. The non-crystalline nature of the obtained sample was confirmed through the presence of XRD broadband in the range 2θ = 16°–46°. Also, the obtained sample was utilized as an economically inexpensive and efficient adsorbent for the removal of methylene blue dye from aqueous media. Besides, several parameters were examined for evaluating the removal of methylene blue dye, for example, kinetic, equilibrium, thermodynamic, and reusability. Moreover, the Freundlich isotherm and pseudo-first-order kinetic model controlled the adsorption process. The maximum adsorption capacity of the obtained adsorbent was 102.05 mg/g. In addition, the negative ∆G° values affirmed the spontaneous properties of the adsorption. Also, the adsorption was exothermic and physical because ∆H° is negative and less than 40 kJ/mol. Finally, the obtained adsorbent was regenerated then reused several times without changing their removing efficiency.

Comparative study of crystallite size using Williamson-Hall and Debye-Scherrer plots for ZnO nanoparticles

ZnO nanoparticles at different pH were synthesised by a sol-gel technique from zinc acetate dihydrate at a calcination temperature of 450 °C. The synthesized ZnO nanoparticles were characterised by x-ray diffraction (XDR) peak profile analysis, high-resolution scanning electron microscopy and Fourier transform infrared spectroscopy. The effects of solution pH on the crystallite size using Williamson-Hall and Debye–Scherrer were determined. The XRD analysis of the zincite phase structure of ZnO nanoparticles was obtained in the form of spheres for all the samples. The average crystallite sizes of ZnO nanoparticles decrease with increasing pH. The crystallite sizes of ZnO nanoparticles were investigated using Williamson-Hall analysis and Scherrer’s formula. The parameters such as dislocation density and lattice strain were computed for the diffraction peaks of XRD in the range of 2θ = 10–90°. The results showed that the crystallite sizes calculated from Scherrer’s equation and Williamson-Hall analysis from XRD are not inter-correlated. Both methods give a wide deviation of crystallite size. Also, it was found that the crystallite sizes using both methods decrease with an increase in pH. Smaller crystallite sizes were estimated using the Scherrer’s formula. Thus, it is deduced that the equation fitted well for the synthesised ZnO nanoparticles.

PHASE RELATION STUDIES IN THE ZrO2-CeO2-Dy2O3 SYSTEM AT 1500 °С

The systems containing ceria, dysprosium and zirconia are perspective for the development of energy saving technological solutions and solid oxide fuel cells (SOFC). Ceramics based on ZrO 2 is used as a high temperature electrolyte for SOFC. The solid solutions based on CeО 2 are the most perspective electrolytes, operating at moderate temperatures, because of their ionic conductivity and high sensitivity to changes of oxygen partial pressure is much higher than ones of ZrO 2 stabilized with Y 2 O 3 (YSZ). In the present work, first the phase equilibria and physicochemical properties for solid solutions in the ternary ZrО 2 -CeО 2 -Dy 2 O 3 system at temperature 1500 °С (150 h) in air were studied by X-ray diffraction in the overall concentration range of compositions. Cerium oxide nitrate Ce(NO 3 ) 3 ∙6H 2 O and zirconium oxide nitrate ZrO(NO 3 ) 2 ×2Н 2 О of grade «ch» (above 98%, dysprosium oxide (99.99 % produced by Merck Corp.) and analytical-grade nitric acid were used as the starting materials. Samples were prepared with a concentration step of 1-5 mol % from nitrate solutions with subsequent evaporation and decomposіtion of nitrates into oxides through annealing at 1200 °С for 2 h. Powders were pressed in pellets (diameter 5 mm, height 4 mm) under a pressure of 10-30 MPа. XRD analysis of samples was performed by powder procedure on a DRON-3 apparatus at ambient temperature under CuКa radiation. Scanning step was 0.05-0.1 degrees in the range 2θ = 15–90°. Lattice parameters were calculated by the least square method using the LATTIC computer code with an error of not lower than 0.0001 nm for the cubic phase. Any new phase in the ternary system was revealed at 1500 °С. The structure of the boundary binary systems defines the phase equilibria in the ZrО 2 -CeО 2 -Dy 2 O 3 system. Solid solutions based on tetragonal (Т) modification ZrО 2 , cubic (С) modification Dy 2 O 3 and cubic with fluorite-type structure (F) modifications СеО 2 (ZrО 2 ) were determined.

The effect of annealing temperatures on the optical parameters of NiO0.99Cu0.01 thin films

NiO0.99Cu0.01 films have been deposited using thermal evaporationtechnique on glass substrates under vacuum 10-5mbar. The thicknessof the films was 220nm. The as -deposited films were annealed todifferent annealing temperatures (373, 423, and 473) K undervacuum 10-3mbar for 1 h. The structural properties of the films wereexamined using X-ray diffraction (XRD). The results show that noclear diffraction peaks in the range 2θ= (20-50)o for the as depositedfilms. On the other hand, by annealing the films to 423K in vacuumfor 1 h, a weak reflection peak attributable to cubic NiO wasdetected. On heating the films at 473K for 1 h, this peak wasobserved to be stronger. The most intense peak is at 2θ = 37.12o withthe preferential orientation of the films being (111) plane. The opticalproperties of the films have been studied. The effect of annealingtemperature on the optical parameters of NiO0.99Cu0.01 such astransmittance, reflectance, absorption coefficient, refractive index,extinction coefficient, and real and imaginary parts of dielectricconstant has been reported.

Polypropylene Nanocomposite Employing Sodium Clay as Support for an Isospecific Metallocene Complex

Propylene polymerization was performed using homogeneous and supported rac‐SiMe2(2‐Me‐Ind)2ZrCl2 catalysts. The supports used were commercial sodic bentonites from different sources. The influence of polymerization time and nature of catalyst support on the nanocomposites syntheses and the consequent properties of obtained composites, were evaluated at two different reaction temperatures and with two cocatalyst systems (MAO and a mixture of MAO/TIBA). The highest catalytic activities were obtained at 60 °C with the cocatalyst mixture MAO/TIBA in the reaction medium. Polymerization rate profiles were obtained as well as melting and crystallization temperatures, crystallinity degree, isotactic index, and number‐average molecular weight. The polypropylene produced with the supported catalyst pretreated with TIBA instead of MAO showed higher crystallinity degree, melting and crystallization temperatures, however, it presented lower catalyst activity. Clay exfoliation was verified by the absence of diffraction peak in the range of 2θ from 2.5° to 7° of X‐ray diffractometry analyses and by transmission electron microscopy. The thermogravimetric analyses showed an increase of PP degradation temperature of above 70 °C when synthesized with clay supported catalysts in relation to the PP obtained by means of homogeneous system.

Karakterisasi Bionanofiller Dari Limbah Padi Sebagai Alternatif Penguatan Pada Polimer Komposit

&lt;p&gt;Agricultural waste such as rice straw, rice husk and rice husk ash have not been utilized properly. This waste of agricultural produce can actually be used as an alternative to bionanofiller because it contains an excellent source of silica. The silica content contained in the rice waste when combined with the polymer matrix can produce composites having high thermal and mechanical properties. Characterization of bionanofiller from this rice waste is done by SEM, XRF, FTIR, XRD and particle density. The result of SEM analysis from this rice waste is feasible to be used as filler because it has size 1 μm. Likewise with the results of XRF analysis that rice waste contains a high enough silica component that is 80.6255% - 89.83%. FTIR test results also show that bionanoparticles from rice waste have the same content of silica. In the XRD analysis the best selective gain of rice waste is found in rice husk ash which is characteristic of amorp silica at a range of 2ϴ = 22&lt;br /&gt;. The largest density analysis of paddy waste was found in rice husk 0.0419 gr / cm , followed by rice straw by of 0.0417 gr / cm 3 and rice hulk ash 0.0407 g / cm 3&lt;/p&gt;