Structural and Optical Studies of CdS Nanocomposites Synthesized by Various Routes

2008 ◽  
Vol 8 (8) ◽  
pp. 4188-4192 ◽  
Author(s):  
Gouri Sankar Paul ◽  
Pratima Agarwal
Keyword(s):  
Quantum Confinement Effect ◽  
High Surface ◽  
Aqueous Media ◽  
Thermo Gravimetric Analysis ◽  
Volume Ratio ◽  
Stoichiometric Ratio ◽  
Particle Sizes ◽  
Gravimetric Analysis ◽  
Phonon Modes ◽  
Cds Nanocomposites

Structural and optical properties of CdS nanocomposites prepared by two different routes are presented in this paper. While CdS prepared by aqueous media results in the formation of nanoparticles of particle sizes 8–9 nm; the solvothermal process results in the formation of nanorods of diameter 40–50 nm and length 450–750 nm where particle sizes were confirmed by SEM and TEM. XRD studies confirm that the structure of these nanocomposites is wurzite. EDAX give the stoichiometric ratio. UV-Vis and photoluminescence (PL) measurements show a blue shift compared to bulk CdS, supporting quantum confinement effect. Nanocomposites are found to be stable up to 650 °C was observed by thermo gravimetric analysis (TGA). The Raman scattering studies show that in addition to LO and TO phonon modes, peak corresponding to surface phonon modes are present in both cases, which are due to high surface to volume ratio. The CdS nanocomposites can therefore be used for various stable optoelectronic devices.

Application of radiation grafted waste polypropylene fabric for the effective removal of Cu (II) and Cr (III) ions

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Md. Nabul Sardar ◽  
Nazia Rahman ◽  
Shahnaz Sultana ◽  
Nirmal Chandra Dafader
Keyword(s):  
Adsorption Capacity ◽  
Metal Ion ◽  
Aqueous Media ◽  
Thermo Gravimetric Analysis ◽  
Ion Concentration ◽  
Gravimetric Analysis ◽  
Order Kinetic ◽  
Polypropylene Fabric ◽  
Alternative Material ◽  
Waste Polypropylene

Abstract This study focuses on the adsorption of hazardous Cr (III) and Cu (II) ions from aqueous solution by applying modified waste polypropylene (PP) fabric as an adsorbent. Pre-irradiation technique was performed for grafting of sodium styrene sulfonate (SSS) and acrylic acid (AAc) onto the PP fabric. The monomer containing 8% SSS and 16% AAc in water was used. Graft yield at 30 kGy radiation dose was 390% when 4% NaCl was added as additive. The prepared adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA) and dynamic mechanical analyzer (DMA). The influences of different parameters including pH, contact time, temperature and initial metal ion concentration were also investigated. The equilibrium adsorption data were better fitted to the Langmuir isotherm model with maximum monolayer adsorption capacity 384.62 mg/g for Cr (III) and 188.68 mg/g for Cu (II) ions. The kinetic data were better explained by pseudo first-order kinetic model having good matching between the experimental and theoretical adsorption capacity. The adsorption process was spontaneous, endothermic and thermodynamically feasible. Furthermore, investigation of desorption of metal ions and reuse of the adsorbent suggesting that the adsorbent is an efficient and alternative material in the removal of Cr (III) and Cu (II) from aqueous media.

Doping of Palladium in Silica Nanofibers via Electrospinning and Sol-Gel Synthesize as Hydrogen Storage Material

2011 ◽  
Vol 471-472 ◽  
pp. 1040-1045 ◽  
Author(s):  
Samaneh Shahgaldi ◽  
Zahira Yaakob ◽  
Dariush Jafar Khadem ◽  
Wan Ramli Wan Daud ◽  
Edy Herianto Majlan
Keyword(s):  
Hydrogen Storage ◽  
Surface Area ◽  
High Surface ◽  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
High Surface Area ◽  
Chemical Vapour ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Silica Nanofibers

In recent years, one dimensional nanostructure, nanowires, nanofibers with unique properties have been a subject of intense research due to reduction of devise dimension, potential properties from the re-arrangement at the molecular level and high surface area. There are many methods for synthesize such as laser ablation, chemical vapour deposition, solution method micro pulling down method but all these method faced to the major disadvantages of being complicated with long wasting time and relatively high expense . The electrospinning recently used for producing ceramic, metal, and carbon nanofibers. In this report, we incorporate palladium into silica nanofibers for the first time, and the effect of doping of palladium into the silica nanofibers is investigated. The different ratio of palladium to silica and comparing with silica nanofibers is also reported. The composition, morphology, structure and surface area of silica, and silica palladium nanofibers were investigated by thermo gravimetric analysis (TGA), x-ray diffraction (XRD), scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FT-IR), and Micromeriics. To the best of our knowledge, investigation on characteristic on Silica palladium nanofibers has not been reported up to now. The result reveal that the silica nanofibers compare to silica doped with palladium have lower diameter, and also by increasing the temperature above 600 °C, the reduction in length of nanofibers happened. High surface area of silica palladium nanofibers can be one of the promising materials for hydrogen storage.

Structure and Catalytic Soot Combustion of Perovskite La-Mn-O Hollow Microfibers via Gel-Precursor Transformation Process

2012 ◽  
Vol 538-541 ◽  
pp. 2289-2292
Author(s):  
Xiao Xiao Meng ◽  
Feng Lin He ◽  
Jiang Ying Shen ◽  
Xiang Qian Shen
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Surface ◽  
Thermo Gravimetric Analysis ◽  
Transformation Process ◽  
High Catalytic Activity ◽  
Gravimetric Analysis ◽  
Soot Combustion ◽  
Aspect Ratios

The nanocrystalline perovskite La-Mn-O hollow microfibers were prepared by the gel-precursor transformation process from reagents of metal salts and citric acid. The gel precursor and resultant products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The specific surface area was measured by the Brunauere-Emmette-Teller method. The catalytic performance of soot combustion was evaluated by thermo-gravimetric analysis under model conditions. The nanocrystalline La-Mn-O hollow microfibers calcined at 650 °C for 6 h are characterized with diameters of 2-8 µm, aspect ratios (length/diameter) about 5-15, a micro-tunnel with an estimated ratio 1/3 of the hollow diameter to fiber diameter, and a high specific surface area of 36.7 m2/g that is 1.9 times higher than the counterpart nanosized powder. This nanocrystalline La-Mn-O hollow microfibers catalyst exhibit a high catalytic activity for the soot combustion, with a low T50 of 397°C, which is largely owing to the high surface area and the micro-tunnel structure.

scholarly journals CMOS-Compatible and Low-Cost Thin Film MACE Approach for Light-Emitting Si NWs Fabrication

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 966
Author(s):  
Antonio Alessio Leonardi ◽  
Maria José Lo Faro ◽  
Alessia Irrera
Keyword(s):  
Silicon Nanowires ◽  
Low Cost ◽  
Quantum Confinement Effect ◽  
High Surface ◽  
Volume Ratio ◽  
Cmos Technology ◽  
High Density ◽  
Synthesis Methods ◽  
Light Emitting ◽  
Strong Control

Silicon nanowires (Si NWs) are emerging as an innovative building block in several fields, such as microelectronics, energetics, photonics, and sensing. The interest in Si NWs is related to the high surface to volume ratio and the simpler coupling with the industrial flat architecture. In particular, Si NWs emerge as a very promising material to couple the light to silicon. However, with the standard synthesis methods, the realization of quantum-confined Si NWs is very complex and often requires expensive equipment. Metal-Assisted Chemical Etching (MACE) is gaining more and more attention as a novel approach able to guarantee high-quality Si NWs and high density with a cost-effective approach. Our group has recently modified the traditional MACE approach through the use of thin metal films, obtaining a strong control on the optical and structural properties of the Si NWs as a function of the etching process. This method is Complementary Metal-Oxide-Semiconductors (CMOS)-technology compatible, low-cost, and permits us to obtain a high density, and room temperature light-emitting Si NWs due to the quantum confinement effect. A strong control on the Si NWs characteristics may pave the way to a real industrial transfer of this fabrication methodology for both microelectronics and optoelectronics applications.

Solid-State Combustion of Metallic Nanoparticles: New Possibilities for an Alternative Energy Carrier

2006 ◽  
Vol 129 (1) ◽  
pp. 29-32 ◽  
Author(s):  
D. B. Beach ◽  
A. J. Rondinone ◽  
B. G. Sumpter ◽  
S. D. Labinov ◽  
R. K. Richards
Keyword(s):  
Solid State ◽  
Metallic Nanoparticles ◽  
Alternative Energy ◽  
High Surface ◽  
Combustion Process ◽  
Volume Ratio ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Regeneration Cycle ◽  
Good Agreement

As an alternative to conventional methods of conveying and delivering energy in mobile applications or to remote locations, we have examined the combustion of nanostructured metal particles assembled into metal clusters. Clusters containing iron nanoparticles (∼50nm in diameter) were found to combust entirely in the solid state due to the high surface-to-volume ratio typical of nanoparticles. Optical temperature measurements indicated that combustion was rapid (∼500ms), and occurred at relatively low peak combustion temperatures (1000-1200K). Combustion produces a mixture of Fe(III) oxides. X-ray diffraction and gravimetric analysis indicated that combustion was nearly complete (93–95% oxidation). Oxide nanoparticles could be readily reduced at temperatures between 673K and 773K using hydrogen at 1atm pressure, and then passivated by the growth of a thin oxide layer. The nanostructuring of the particles is retained throughout the combustion–regeneration cycle. Modeling of the combustion process is in good agreement with observed combustion characteristics.

scholarly journals Electrospun Solid Dispersions of Maraviroc for Rapid Intravaginal Preexposure Prophylaxis of HIV

2014 ◽  
Vol 58 (8) ◽  
pp. 4855-4865 ◽  
Author(s):  
Cameron Ball ◽  
Kim A. Woodrow
Keyword(s):  
Drug Delivery ◽  
Dosage Form ◽  
Drug Loading ◽  
Solid Dispersions ◽  
High Surface ◽  
Aqueous Media ◽  
Volume Ratio ◽  
Water Soluble ◽  
High Drug ◽  
Solid Dosage

ABSTRACTThe development of topical anti-human immunodeficiency virus (HIV) microbicides may provide women with strategies to protect themselves against sexual HIV transmission. Pericoital drug delivery systems intended for use immediately before sex, such as microbicide gels, must deliver high drug doses for maximal effectiveness. The goal of achieving a high antiretroviral dose is complicated by the need to simultaneously retain the dose and quickly release drug compounds into the tissue. For drugs with limited solubility in vaginal gels, increasing the gel volume to increase the dose can result in leakage. While solid dosage forms like films and tablets increase retention, they often require more than 15 min to fully dissolve, potentially increasing the risk of inducing epithelial abrasions during sex. Here, we demonstrate that water-soluble electrospun fibers, with their high surface area-to-volume ratio and ability to disperse antiretrovirals, can serve as an alternative solid dosage form for microbicides requiring both high drug loading and rapid hydration. We formulated maraviroc at up to 28 wt% into electrospun solid dispersions made from either polyvinylpyrrolidone or poly(ethylene oxide) nanofibers or microfibers and investigated the role of drug loading, distribution, and crystallinity in determining drug release rates into aqueous media. We show here that water-soluble electrospun materials can rapidly release maraviroc upon contact with moisture and that drug delivery is faster (less than 6 min under sink conditions) when maraviroc is electrospun in polyvinylpyrrolidone fibers containing an excipient wetting agent. These materials offer an alternative dosage form to current pericoital microbicides.

scholarly journals Green Synthesis of Flower-Shaped Copper Oxide and Nickel Oxide Nanoparticles via Capparis decidua Leaf Extract for Synergic Adsorption-Photocatalytic Degradation of Pesticides

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 806
Author(s):  
Amna Iqbal ◽  
Atta ul Haq ◽  
Gabriel Antonio Cerrón-Calle ◽  
Syed Ali Raza Naqvi ◽  
Paul Westerhoff ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Leaf Extract ◽  
High Surface ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Order Kinetic ◽  
Face Centered Cubic ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Capparis Decidua

Green manufacturing of catalysts enables sustainable advanced oxidation processes and water treatment processes for removing trace contaminants such as pesticides. An environmentally friendly biosynthesis process produced high-surface-area CuO and NiO nanocatalysts using phytochemicals in the Capparis decidua leaf extract, which served as a reductant and influenced catalyst shape. Capparis decidua is a bushy shrub, widely distributed in dry and arid regions of Africa, Pakistan, India, Egypt, Jordan, Sudan, Saudi Arabia. The synthesized CuO and NiO nanoparticles were characterized by UV-vis spectroscopy (UV-vis), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) and thermo-gravimetric analysis/differential thermal analysis (TGA/DTA). The produced nanoparticles were spherical and flower-like in shape and have a characteristic face-centered cubic structure of CuO and NiO. Biosynthesized catalysts were photoactive and degraded recalcitrant pesticide Lambda-cyhalothrin (L-CHT). Photocatalytic degradation of L-CHT was affected by the initial L-CHT concentration, solution pH levels between 5 and 9, and photocatalyst concentration. The L-CHT removal percentage attained by CuO photocatalyst (~99%) was higher than for NiO photocatalyst (~89%). The degradation of L-CHT follows a pseudo-first-order kinetic model, and the apparent rate constant (kapp) decreased from 0.033 min−1 for CuO to 0.0084 min−1 for NiO photocatalyst. The novel flower-shaped nanoparticles demonstrated high stability in water and recyclability for removing L-CHT pesticide contamination in water.

Synthesis of Smart Mesoporous Materials

2003 ◽  
Vol 775 ◽  
Author(s):  
G.V.Rama Rao ◽  
Qiang Fu ◽  
Linnea K. Ista ◽  
Huifang Xu ◽  
S. Balamurugan ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Mesoporous Materials ◽  
Fluorescent Dyes ◽  
Thermo Gravimetric Analysis ◽  
Molecular Transport ◽  
Solute Diffusion ◽  
Gravimetric Analysis ◽  
Stimuli Responsive ◽  
Porous Network ◽  
Hybrid Mesoporous Materials

AbstractThis study details development of hybrid mesoporous materials in which molecular transport through mesopores can be precisely controlled and reversibly modulated. Mesoporous silica materials formed by surfactant templating were modified by surface initiated atom transfer radical polymerization of poly(N-isopropyl acrylamide) (PNIPAAm) a stimuli responsive polymer (SRP) within the porous network. Thermo gravimetric analysis and FTIR spectroscopy were used to confirm the presence of PNIPAAm on the silica surface. Nitrogen porosimetry, transmission electron microscopy and X-ray diffraction analyses confirmed that polymerization occurred uniformly within the porous network. Uptake and release of fluorescent dyes from the particles was monitored by spectrofluorimetry and scanning laser confocal microscopy. Results suggest that the presence of PNIPAAm, a SRP, in the porous network can be used to modulate the transport of aqueous solutes. At low temperature, (e.g., room temperature) the PNIPAAm is hydrated and extended and inhibits transport of analytes; at higher temperatures (e.g., 50°C) it is hydrophobic and is collapsed within the pore network, thus allowing solute diffusion into or out of the mesoporous silica. The transition form hydrophilic to hydrophobic state on polymer grafted mesoporous membranes was determined by contact angle measurements. This work has implications for the development of materials for the selective control of transport of molecular solutes in a variety of applications.

Coordination Compounds of Some 3d-Transition Metal Ions with N1-[4-(4-bromo-phenylsulfonyl)-benzoyl]-N4-(4-methoxyphenyl)- thiosemicarbazide

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Madalina Angelusiu ◽  
Maria Negoiu ◽  
Stefania-Felicia Barbuceanu ◽  
Tudor Rosu
Keyword(s):  
Coordination Compounds ◽  
Magnetic Moments ◽  
Thermo Gravimetric Analysis ◽  
Electronic Spectroscopy ◽  
Transition Metal Ions ◽  
Synthesis And Characterization ◽  
Gravimetric Analysis ◽  
Thermo Gravimetric ◽  
New Compounds

The paper presents the synthesis and characterization of Cu(II), Co(II), Ni(II), Cd(II), Zn(II) and Hg(II) complexes with N1-[4-(4-bromo-phenylsulfonyl)-benzoyl]-N4-(4-methoxyphenyl)-thiosemicarbazide. The new compounds were characterized by IR, EPR, electronic spectroscopy, magnetic moments, thermo-gravimetric analysis and elemental analysis.

Collagen And Carbon-Ferrous Nanoparticles Used As A Green Energy Composite Material For Energy Storage Devices

2020 ◽  
Vol 13 ◽  
Author(s):  
Inbasekaran S. ◽  
G. Thiyagarajan ◽  
Ramesh C. Panda ◽  
S. Sankar
Keyword(s):  
Composite Material ◽  
Thermo Gravimetric Analysis ◽  
Value Added ◽  
Green Energy ◽  
Nano Particles ◽  
Hydroxyl Group ◽  
Gravimetric Analysis ◽  
Circuit Testing ◽  
Battery Cell ◽  
Dc Voltage

Background:: Chrome shavings, a bioactive material, are generated from tannery as waste material. These chrome shaving can be used for the preparation of many value-added products. Objective:: One such attempt is made to use these chrome shaving wastes as a composite bio-battery to produce DC voltage, an alternate green energy source and cleaner technology. Methods:: Chrome shavings are hydrolyzed to make collagen paste and mixed with the ferrous nanoparticles of Moringa oleifera leaves and Carbon nanoparticles of Onion peels to form electrolyte paste as base. Then, the electrolyte base was added to the aluminum paste and conducting gel, and mixed well to form composite material for bio-battery. Results:: The composite material of bio-battery has been characterized using Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA). Series and parallel circuit testing were done using Copper and Zinc electrodes or Carbon and Zinc electrodes as the battery terminals in the electrolyte paste. The surface area of these electrodes needs standardization from bench to pilot scale. The power generated, for an AA battery size, using a single bio-battery cell has produced a DC voltage of 1.5 V; current of 900 mA. Circuit testing on 1 ml of 80 well-cells connected in series has produced DC output of 18 V and 1100 mA whereas 48 V and 1500 mA were obtained from a series-parallel connection. Conclusion:: The glass transition temperature (Tg) of electrolyte of the bio-battery at 53°C indicates that, at this temperature, all the substances present in the bio-battery are well spread and contributing consistently to the electrolyte activity where Fe-C-Nano-Particles were able to form strong chemical bonds on the flanking hydroxyl group sites of the Collagen leading to reduced mobility of polymers and increase Tg. The results instigate promising trends for commercial exploitation of this composite for bio-battery production.

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