scholarly journals One-Pot Synthesis of Nano CuO-ZnO Modified Hydrochar Derived from Chitosan and Starch for the H2S Conversion

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 767
Author(s):  
Lihua Zang ◽  
Chengxuan Zhou ◽  
Liming Dong ◽  
Leilei Wang ◽  
Jiaming Mao ◽  
...  
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Amine Group ◽  
Amino Groups ◽  
One Pot ◽  
H2s Adsorption ◽  
Oxide Particles ◽  
Sulfur Capacity ◽  
Rapid Diffusion ◽  
Optimized Conditions

A novel kind of hydrochar adsorbent, modified by CuO-ZnO and derived from chitosan or starch, was synthesized for H2S adsorption. The prepared adsorbent was characterized by BET, XRD, EDX, SEM, and XPS. The results showed that the modified hydrochar contained many amino groups as functional groups, and the nanometer metal oxide particles had good dispersion on the surface of the hydrochar. The maximum sulfur capacity reached 28.06 mg/g-adsorbent under the optimized conditions. The amine group significantly reduced the activation energy between H2S and CuO-ZnO conducive to the rapid diffusion of H2S among the lattices. Simultaneously, cationic polyacrylamide as a steric stabilizer could change the formation process of CuO and ZnO nanoparticles, which made the particle size smaller, enabling them to react with H2S sufficiently easily. This modified hydrochar derived from both chitosan and starch could be a promising adsorbent for H2S removal.

Study of the microstructure and particles of vanadium (III) oxide, vanadium (V) oxide and lithium aluminate powders

2020 ◽  
Vol 86 (1) ◽  
pp. 32-37
Author(s):  
Valeria A. Brodskaya ◽  
Oksana A. Molkova ◽  
Kira B. Zhogova ◽  
Inga V. Astakhova
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Vanadium Oxide ◽  
Size Distribution ◽  
Microstructural Analysis ◽  
Coherent Scattering ◽  
Powder Materials ◽  
Lithium Aluminate ◽  
Range Limit ◽  
Oxide Particles

Powder materials are widely used in the manufacture of electrochemical elements of thermal chemical sources of current. Electrochemical behavior of the powders depends on the shape and size of their particles. The results of the study of the microstructure and particles of the powders of vanadium (III), (V) oxides and lithium aluminate obtained by transmission electron and atomic force microscopy, X-ray diffraction and gas adsorption analyses are presented. It is found that the sizes of vanadium (III) and vanadium (V) oxide particles range within 70 – 600 and 40 – 350 nm, respectively. The size of the coherent-scattering regions of the vanadium oxide particles lies in the lower range limit which can be attributed to small size of the structural elements (crystallites). An average volumetric-surface diameter calculated on the basis of the surface specific area is close to the upper range limit which can be explained by the partial agglomeration of the powder particles. Unlike the vanadium oxide particles, the range of the particle size distribution of the lithium aluminate powder is narrower — 50 – 110 nm. The values of crystallite sizes are close to the maximum of the particle size distribution. Microstructural analysis showed that the particles in the samples of vanadium oxides have a rounded (V2O3) or elongated (V2O5) shape; whereas the particles of lithium aluminate powder exhibit lamellar structure. At the same time, for different batches of the same material, the particle size distribution is similar, which indicates the reproducibility of the technologies for their manufacture. The data obtained can be used to control the constancy of the particle size distribution of powder materials.

scholarly journals Aqueous one-pot synthesis of well-defined zwitterionic diblock copolymers by RAFT polymerization: an efficient and environmentally-friendly route to a useful dispersant for aqueous pigments

2021 ◽  
Vol 23 (3) ◽  
pp. 1248-1258
Author(s):  
Shannon M. North ◽  
Steven P. Armes
Keyword(s):  
Iron Oxide ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Environmentally Friendly ◽  
Iron Oxide Particles ◽  
One Pot ◽  
One Pot Synthesis ◽  
Highly Effective ◽  
Oxide Particles

An atom-efficient, wholly aqueous one-pot synthesis of zwitterionic diblock copolymers has been devised. Such copolymers can serve as highly effective aqueous dispersants for nano-sized transparent yellow iron oxide particles.

scholarly journals Tuning morphology, surface, and nanocrystallinity of rare earth vanadates by one-pot colloidal conversion of hydroxycarbonates

Nanoscale ◽  
2021 ◽  
Author(s):  
Gabriela Guida ◽  
Steven Huband ◽  
Marc Walker ◽  
Richard I. Walton ◽  
Paulo C. de Sousa Filho
Keyword(s):  
Particle Size ◽  
Rare Earth ◽  
Defect Density ◽  
Spectroscopic Properties ◽  
One Pot

The mechanisms of a one-pot colloidal conversion of hydroxycarbonate templates into vanadate nanoparticles were investigated, with further correlation of Eu3+ spectroscopic properties to particle size, texture, nanocrystallinity, and defect density.

scholarly journals Green Light Emission ofZnxCd1-xSeNanocrystals Synthesized by One-Pot Method

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shu-Ru Chung ◽  
Kuan-Wen Wang ◽  
Hong-Shuo Chen
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Light Emission ◽  
Green Light ◽  
Particle Size Effect ◽  
Partial Replacement ◽  
Face Centered Cubic ◽  
One Pot ◽  
Zn Content ◽  
High Emission

We present a facile one-pot synthesis to prepare ternaryZnxCd1-xSe(x= 0.2, 0.5, 0.8, and 1) nanocrystals (NCs) with high emission quantum yield (QY, 45~89%). The effect of Zn content (x) ofZnxCd1-xSeNCs on their physical properties is investigated. The NCs have a particle size of 3.2 nm and face centered cubic structure. However, the actual compositions of the NCs are Zn0.03Cd0.97Se, Zn0.11Cd0.89Se, and Zn0.38Cd0.62Se when Zn content is 0.2, 0.5, and 0.8, respectively. In terms of the optical properties, the emission wavelength shifts from 512 to 545 nm with increasing Zn content from 0 to 0.8 while the QY changes from 89 to 45, respectively. Partial replacement of Cd by Zn is beneficial to improve the QY of Zn0.2and Zn0.5NCs. The optical properties of ternary NCs are affected by compositional effect rather than particle size effect.

Nitrocellulose Catalyzed With Manganese Oxide Nanoparticles: Advanced Energetic Nanocomposite With Superior Decomposition Kinetics

2021 ◽  
Author(s):  
Sherif Elbasuney ◽  
M. Yehia ◽  
Shukri Ismael ◽  
Yasser El-Shaer ◽  
Ahmed Saleh
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Manganese Oxide ◽  
Energetic Materials ◽  
Average Particle Size ◽  
Active Surface ◽  
Propagation Rate ◽  
Hydroxyl Groups ◽  
Average Particle ◽  
Decomposition Enthalpy

Abstract Nanostructured energetic materials can fit with advanced energetic first-fire, and electric bridges (microchips). Manganese oxide, with active surface sites (negatively charged surface oxygen, and hydroxyl groups) can experience superior catalytic activity. Manganese oxide could boost decomposition enthalpy, ignitability, and propagation rate. Furthermore manganese oxide could induce vigorous thermite reaction with aluminium particles. Hot solid or liquid particles are desirable for first-fire compositions. This study reports on the facile fabrication of MnO2 nanoparticles of 10 nm average particle size; aluminium nanoplates of 100 nm average particle size were employed. Nitrocellulose (NC) was adopted as energetic polymeric binder. MnO2/Al particles were integrated into NC matrix via co-precipitation technique. Nanothermite particles offered an increase in NC decomposition enthalpy by 150 % using DSC; ignition temperature was decreased by 8 0C. Nanothemrite particles offered enhanced propagation index by 261 %. Kinetic study demonstrated that nanothermite particles experienced drastic decrease in NC activation energy by - 42, and - 40 KJ mol-1 using Kissinger and KAS models respectively. This study shaded the light on novel nanostructured energetic composition, with superior combustion enthalpy, propagation rate, and activation energy.

scholarly journals Green Preparation, Spheroidal, and Superior Property of Nano-1,3,5,7-Tetranittro-1,3,5,7-Tetrazocane

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Xinlei Jia ◽  
Jingyu Wang ◽  
Conghua Hou ◽  
Yingxin Tan
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Fractal Dimension ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fractal Theory ◽  
Crystal Form ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
The Impact

Herein, a green process for preparing nano-HMX, mechanical demulsification shearing (MDS) technology, was developed. Nano-HMX was successfully fabricated via MDS technology without using any chemical reagents, and the fabrication mechanism was proposed. Based on the “fractal theory,” the optimal shearing time for mechanical emulsification was deduced by calculating the fractal dimension of the particle size distribution. The as-prepared nano-HMX was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). And the impact sensitivities of HMX particles were contrastively investigated. The raw HMX had a lower fractal dimension of 1.9273. The ideal shearing time was 7 h. The resultant nano-HMX possessed a particle size distribution ranging from 203.3 nm to 509.1 nm as compared to raw HMX. Nano-HMX particles were dense spherical, maintaining β-HMX crystal form. In addition, they had much lower impact sensitivity. However, the apparent activation energy as well as thermal decomposition temperature of nano-HMX particles was decreased, attributing to the reduced probability for hotspot generation. Especially when the shearing time was 7 h, the activation energy was markedly decreased.

High Tc Oxide Solid State Reaction Kinetics Via Complex Impedance Spectroscopy

1989 ◽  
Vol 169 ◽  
Author(s):  
E. A. Cooper ◽  
T. O. Mason ◽  
U. Balachandran ◽  
M. L. Kullberg
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Solid State ◽  
Solid State Reaction ◽  
Complex Impedance ◽  
Particle Size Effect ◽  
Large Temperature ◽  
Impedance Spectra ◽  
High Tc ◽  
Solid State Reaction Kinetics

AbstractImpedance spectra (5Hz ‐ 13MHz) were collected during the solid state reaction of Yba2Cu2O6+y from large monosized CuO particles imbedded in a finely divided Y2 O3 /BaCO3 matrix. No particle size effect was observed, but a large temperature effect was observed corresponding to an activation energy of approximately 1.8eV (175kJ/mol) over the range 700‐900°C.

scholarly journals Preparation of Apatite-Wollastonite-Phlogopite glass-ceramic composites by powder sintering method

2013 ◽  
Vol 45 (3) ◽  
pp. 331-339
Author(s):  
A. Faeghi-Nia
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Glass Ceramic ◽  
Ceramic Composite ◽  
Ceramic Composites ◽  
Powder Sintering ◽  
Powdered Glass ◽  
Activation Energy Of Sintering ◽  
Sintering Method ◽  
Glass Ceramic Composite

An Apatite-Wollastonite-Phlogopite glass-ceramic composite, was developed by sintering and crystallization of the powdered glass. The non-isothermal and isothermal sintering kinetics were studied for this glass-ceramic. Hot-stage microscopy (HSM) measurements demonstrated that it is possible to sinter and crystallize this glass-ceramic with 80% relative density. The activation energy of sintering was analyzed using previously reported model of sintering and it was obtained Q=193.83 KjmolK-1. Also it was shown that the microstructure of sample is a function of particle size distribution.

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