Keywords : characterization

Phosphorus Gasification during the Reduction of basic Oxygen Furnace Slags in a Novel Reactor Concept

Christoph Ponak; Valentin Mally; Stefan Windisch; Alexandra Holzer; Harald Raupenstrauch

Advanced Materials Letters, 2020, Volume 11, Issue 7, Pages 1-7
DOI: 10.5185/amlett.2020.071535

The research presented in this publication focuses on the removal of phosphorus from basic oxygen furnace slags via the gas phase during carbo-thermal reduction in a bed of inductively heated graphite pieces. Its purpose is to evaluate the effect of the application of a novel reactor concept on the possibilities of phosphorus gasification. The slags are processed in two steps during the experimental trial: First, a silica source is added to reduce the basicity of the slag. In a second step, the actual reduction process is conducted at reaction temperatures of 1,623 K, 1,773 K and 1,923 K, respectively. The molten slag forms a film moving down the reactor with minimal contact time between iron (l) and phosphorus (g) so that a high amount of phosphorus gas can be removed from the reactor. The most important results are that more than 95% of the phosphorus contained in the slags could be reduced, roughly 85% of which were removed via the gas phase. Virtually iron-, chromium- and phosphorus-free slags are obtained. It is concluded that the application of the presented reactor concept based on thermodynamic evaluations potentially tackles the challenges posed by the reaction behaviour of phosphorus.

Optimization of acid hydrolysis process for the preparation cellulose nanofibrils

Melina E. Bracone; Leandro N. Luduena; Vera A. Alvarez

Advanced Materials Letters, 2019, Volume 10, Issue 7, Pages 499-507
DOI: 10.5185/amlett.2019.2182

Cellulose nanofibrils can be obtained from microcrystalline cellulose by acid hydrolysis processes. Under optimum hydrolysis conditions is possible to obtain cellulose nanofibers with high surface/volume ratio, high aspect ratio (length to diameter), high crystallinity and improved thermal stability. All these parameters then determine their effectiveness as reinforcement in a polymer matrix. In this work, cellulose nanofibrils were obtained from commercial microcellulose supplied by Aldrich. The acid hydrolysis synthesis was optimized studying the effect of reaction time and temperature and acid solution concentration. The optimized parameters were selected so as to obtain fibers with high crystallinity, high aspect ratio with diameter in nanoscale and high thermal stability. The morphology and size (length and diameter) of the fibers was analyzed by Field Emission Scanning Electron Microscopy (FESEM), the chemical structure by Fourier Transform Infrared Spectroscopy (FTIR), thermal stability by Thermogravimetric Analysis (TGA) and crystallinity by X-ray Diffraction (XRD). Copyright © VBRI Press.

Preparation And Physical Characterization Of CdTe Thin Films Deposited By Vacuum Evaporation For Photovoltaic Applications

Subhash Chander; M. S. Dhaka

Advanced Materials Letters, 2015, Volume 6, Issue 10, Pages 907-912
DOI: 10.5185/amlett.2015.5926

The present communication reports the preparation and physical characterization of CdTe thin films for photovoltaic application. The thin films of thickness 660 nm and 825 nm were deposited on glass and ITO coated glass substrates employing thermal vacuum evaporation deposition method. These as-deposited films were characterized using XRD, UV-Vis spectrophotometer, source meter, SEM and AFM for physical properties. The XRD patterns reveal that the films are crystallized zinc-blende structure of cubic phase with preferred orientation (111) as well as polycrystalline in nature. The optical and crystallographic parameters are calculated and widely discussed. The optical band gap is found in the range 1.52 - 1.94 eV and observed to decrease with thickness. The current-voltage characteristics show that the current is found to be decreased with thickness and the resistivity is increased. The SEM studies show that the films are homogeneous, uniform and free from crystal defects. The grains in the thin films are similar in size and densely packed. The AFM studies reveal that the surface roughness is observed to increase for higher thickness. The experimental results reveal that the films of thickness 825 nm may be used as absorber layer in CdTe/CdS thin film solar cells due to its optical band gap 1.52 eV which is almost identical with the optimum band gap of CdTe and good crystallinity.

Phytochemical Fabrication And Characterization Of Silver/ Silver Chloride Nanoparticles Using Albizia Julibrissin Flowers Extract

Akl M. Awwad

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 726-730
DOI: 10.5185/amlett.2015.5816

Silver/ silver chloride (Ag/AgCl-NPs) nanoparticles were synthesized by a simple procedure using Albizia julibrissin flowers extract. The flowers of Albizia julibrissin extract acts a reducing, chlorinated and capping agent in the formation of Ag/AgCl-NPs. UV-visible spectroscopy was used to monitor the quantitative formation of silver/ silver chloride nanoparticles. For complete conversion of silver ions to silver/ silver chloride nanoparticles, time of reaction is less than 5 min at temperature 80 o C and 24h in dark conditions at room temperature. The synthesized Ag/AgCl-NPs nanoparticles were characterized with X-ray diffraction (XRD), UV-vis Spectroscopy, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FT-IR). UV-visible absorption studies revealed surface plasmon resonance (SPR) peak around 410-430 nm, confirming the presence of Ag/AgCl nanoparticles. The average particle size ranged from 5-20 nm. The particle size could be controlled by changing the flowers extract, silver ion concentration and temperature. FT-IR spectra of flowers extract before and after the synthesis of silver/ silver chloride nanoparticles were determined to allow identification of possible functional groups responsible for the reduction of silver ions to silver/silver chloride nanoparticles.

Soft Chemical Approach For The Synthesis And Characterization Of Aluminium Copper Oxide (CuAl2O4) Nanaopowder

Taimur Athar

Advanced Materials Letters, 2015, Volume 6, Issue 3, Pages 265-270
DOI: 10.5185/amlett.2015.5659

With the help of facile single source molecular precursor the synthesis of CuAl2O4 nanopowder with well-defined structural framework was carried out via cost-effective soft–chemical approach with two and three coordination state around copper and Aluminum atom respectively. The synthesized nanoparticles were thoroughly characterized by using several physicochemical techniques such as XRD, SEM, TEM, thermal analysis, UV and FT-IR for structural, optical and morphological studies. With the adjustment of reaction parameters allows us for systematic tuning of particle size, shape as well as to control the other functional properties. It can be concluded that self-assembly is an integral part which take place by understanding the metal chemistry during synthetic approach and therefore help to opens a new exciting opportunities for better understanding the reaction conditions, growth and along its mechanistic approach which leads to fabrication of potential nanodevise in near future.

Biosynthesis Of Colloidal Copper Hydroxide Nanowires Using Pistachio Leaf Extract

Akl M. Awwad; Borhan Albiss

Advanced Materials Letters, 2015, Volume 6, Issue 1, Pages 51-54
DOI: 10.5185/amlett.2015.5630

Copper hydroxide nanowires were synthesized from copper chloride dihydrate and sodium hydroxide in the  presence of Pistachio leaf extract  at room temperature. The results of scanning electron microscopy (SEM)  exhibited  that the copper hydroxide  Cu(OH)2  are nanowires  in shape and having  an average diameter of ca. 10 nm and lengths of up to 500 nm . The Fourier transfor infrared  spectroscopy (FT-IR)  results examined the bioactive functional groups , which acts as dispersing, binding and capping agent for the copper hydroxide nanowires. X-ray diffraction (XRD) spectra confirmed the copper hydroxide nanoparticles crystalline in nature. The current research introduces a new, simple, and rapid route for the in –laboratory synthesis of copper hydroxide nanowires. This facile and green approach may provide a useful tool to large scale synthesis other copper nanoparticles that have potential biotechnology.

Green Synthesis, Characterization And Optical Properties Of Zinc Oxide Nanosheets Using Olea Europea Leaf Extract

Akl M. Awwad; Borhan Albiss; Ahmad L. Ahmad

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 520-524
DOI: 10.5185/amlett.2014.5575

In this paper, a green method is reported for synthesis and characterization of zinc oxide nanosheets using Olea europea leaf extract. ZnO nanosheets were characterized by UV-vis absorption spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The UV-vis absorption spectrum shows an absorption band at 374 nm due to ZnO nanosheets. XRD characterize the final product as highly crystalline ZnO with sizes in the range 18-30 nm. The SEM results reveal a presence of network of randomly oriented ZnO nanosheets or nanoplatelets with an average size of 500 nm and thicknesses of about 20 nm. This facile and green approach may provide a useful tool to large scale synthesis other nanoparticles that have potential biotechnology.

A Convenient Route To Synthesize Hexagonal Pillar Shaped ZnO nanoneedles Via CTAB Surfactant

K. Kaviyarasu; Prem Anand Devarajan

Advanced Materials Letters, 2013, Volume 4, Issue 7, Pages 582-585
DOI: 10.5185/amlett.2012.10443

In this work we report the successful formation of hexagonal pillar shaped ZnO nanoneedles with high yield and by using simple cheap method with CTAB as the surfactant. SEM and TEM microscopic observation revealed that the ZnO nanorods were smooth and uniform throughout their length and the functional groups in the molecule were identified by FTIR analysis. PL properties of ZnO nannorods were found to be dependent on the growth condition and the resultant morphology revealed that ZnO nanorods were highly transparent in the visible region.

Wet-chemical Synthesis Of Spherical Arsenic Nanoparticles By A Simple Reduction Method And Its Characterization

Anjali Pal; Sandip Saha; Sanjoy Kumar Maji; Mainak Kundu; Arpan Kundu

Advanced Materials Letters, 2012, Volume 3, Issue 3, Pages 177-180
DOI: 10.5185/amlett.2011.9305

his paper has demonstrated, for the first time, the synthesis of yellowish-brown colored stable As(0) sol by borohydride-reduction of aqueous sodium arsenite maintained at pH 7-9 under ambient condition. Scanning electron microscopic (SEM) images reveal the formation of spherical As(0) nanoparticles having size in the range 67?2 nm. The transmission electron microscopic (TEM) studies show the particle size lie within the range 60?3 nm. The X-ray photoelectron spectroscopy (XPS) indicates the zero oxidation state of arsenic. The dynamic light scattering (DLS) studies show that the average particle size is around 45 nm. The absorbance of yellowish-brown As(0) sol at 300 nm shows excellent correlation with arsenic concentration in the range 15.6 – 45.4 ? 10-5 M. The method is simple and reproducible. Also by measuring the turbidity, the quantification of arsenic is possible in the range mentioned. The effects of various ions and temperature on the formation of arsenic nanosol have been reported. The as-prepared As(0) nanoparticles may have potential applications in medicine and sensors.

Structural and hardness of nonlinear optical L-alanine single crystals

S. Gokul Raj; G. Ramesh Kumar

Advanced Materials Letters, 2011, Volume 2, Issue 3, Pages 176-182
DOI: 10.5185/amlett.2011.1219

Single crystals of pure and Deuterated L-alanine have been grown by both slow cooling and seed rotation techniques. The grown nonlinear optical crystals were subjected to single crystal X-ray diffraction for determining its lattice parameters and morphology. Thermal expansion measurements were carried for the Deuterated crystals of L-alanine using thermomechanical analyzer in order to ascertain the strain tensors along the three mutually perpendicular crystallographic directions. Microhardness study was also undergone on deuterated L-alanine single crystals on a prominent plane for determining the mechanical strength of the grown crystals. The results have been discussed in detail.

Carboxymethyl Chitosan And Its Applications

V.K Mourya; Nazma N. Inamdara;Ashutosh Tiwari

Advanced Materials Letters, 2010, Volume 1, Issue 1, Pages 11-33
DOI: 10.5185/amlett.2010.3108

Deacetylation of chitin affords chitosan, a polymer, widely studied for its pharmaceutical and nonpharmaceutical applications. The hurdle in comprehending these applications is its limited solubility. Carboxymethylation of chitosan helps to surmount this hurdle with its improved solubility in water. Though there is ample of research related to carboxymethyl chitosan (CMC) the focused review of the topic is unavailable. Hence an attempt is made in this review to cover the recent findings pertaining to synthesis, characterization of CMC and its applications especially in pharmaceutical field. CMC has been synthesized by ways as direct alkylation, reductive alkylation, Michael addition and characterized by FTIR, NMR spectroscopy, and DSC, titrimetry, viscometry, gel permeation chromatography, X-ray diffraction and capillary zone electrophoresis. The carboxymethyl group can be present at O or N or both the atoms of chitosan molecule. The CMC possess modulated physical and biological properties as chelating, sorption, moisture retention, cell functioning antioxidant, antibacterial, antiapoptotic etc. CMC is used in sustained or controlled release drug delivery, pH responsive drug delivery, DNA delivery as permeation enhancer etc. CMC can be further modified with alkylation, acylation, and grafting. Carboxyalkylation of chitosan yield carboxyethyl, carboxybutyl chitosans. These analogues of CMC may be helpful in substantiating the applications of chitosan.