Preparation and Characterization of Cu-Coated Nano SiC Composite Particles

2008 ◽  
Vol 373-374 ◽  
pp. 674-677 ◽  
Author(s):  
Sheng Zhu ◽  
Chao Li ◽  
Jian Hua Du ◽  
Wen Zheng Han
Keyword(s):  
Reaction Mechanism ◽  
Heterogeneous Nucleation ◽  
Oxidation Rate ◽  
Ph Value ◽  
Composite Particles ◽  
Nucleation Process ◽  
Sic Particles ◽  
Reaction Solution ◽  
Reaction Speed

The Cu-coated nano SiC composite particles were prepared by heterogeneous nucleation method. For the heterogeneous nucleation process, the dispered nano SiC particles and the active Cu2O precipitation were both prefabricated. The composite particles were characterized by means of XRD, SEM, EDS, TEM and ED analysis technics. It is found that Cu layers are coated on the nano SiC particles, which are continuous and dense, and partly oxidized to Cu2O, and the oxidation rate can be reduced by improving experimental processes. The investigation on reaction mechanism shows the disproportionating reaction speed of Cu+ can be controlled by adjusting the pH value of reaction solution, which makes the degree of supersaturation of Cu crystallites accord with the conditions of heterogeneous nucleation.

Preparation and Characterization of Al(OH)3 Coated CaF2 Composite Powder

2014 ◽  
Vol 941-944 ◽  
pp. 1597-1601
Author(s):  
Ming Li ◽  
Chong Hai Xu ◽  
Zhao Qiang Chen ◽  
Guang Chun Xiao ◽  
Guang Chao Chu
Keyword(s):  
Reaction Temperature ◽  
Heterogeneous Nucleation ◽  
Composite Powder ◽  
Ph Value ◽  
Main Factors

Al (OH)3 coated CaF2 composite powder was prepared by coating Al (OH)3 on surface of micro-sized CaF2 particles using heterogeneous nucleation method. Influence of Al3+ concentration, PH value and reaction temperature was studied. The result reveals that CaF2 particle was uniformly coated with a layer of Al (OH)3 and Al3+ concentration, pH value and reaction temperature are the main factors that affect coating result. Optimum technological conditions are Al3+ concentration of solution before reaction at 0.15 mol/L, pH value at 7.5 and temperature at 75 oC.

Isolation and Characterization of a Strain of Acidithiobacillus ferrooxidans

2013 ◽  
Vol 777 ◽  
pp. 242-246
Author(s):  
Ju Fang Xiao ◽  
Song Yan Qin ◽  
Peng Huang ◽  
Li Na Guo ◽  
Yi Chun Chen
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Oxidation Rate ◽  
Growth Process ◽  
Ph Value ◽  
Exponential Growth Phase ◽  
Sequencing Analysis ◽  
Isolation And Characterization ◽  
Potential Alternative ◽  
Acid Waste

An acidophilic strain was isolated from drainage in Shanxi coal mine, after 16SrDNA amplification and sequencing analysis, it was identified to be Acidithiobacillus ferrooxidans. The ferrous ion oxidation rate of At.f and pH value were studied during its growth, the results showed that, the strain entering into the exponential growth phase needed about 30 hours, and the oxidation rate was more than 99% after 60 hours. The pH value increased from 2.08 to 2.64 at first 30 hours and then decreased to 2.0, and finally maintained at 2.0 in the whole growth process. The isolated strain provided a potential alternative method to handle the steel-picking sulfuric acid waste liquor.

Synthesis and Characterization of Alkyl-Substituted Polyaniline by Using Ammonium Persulfate as both Oxidant and Dopant

2015 ◽  
Vol 1096 ◽  
pp. 147-155
Author(s):  
Xin Li ◽  
Mei Xiang Wan ◽  
Cong Ju Li
Keyword(s):  
Self Assembly ◽  
Ph Value ◽  
Ammonium Persulfate ◽  
Polymerization Process ◽  
Synthesis And Characterization ◽  
Polymerization Time ◽  
Reaction Solution ◽  
Alkyl Substitution ◽  
Decreasing Ph

Poly (o-toluidine) (POT), poly (m-toluidine) (PMT) and poly (p-toluidine) (PPT) were chemically oxidized by ammonium persulfate (APS) as both oxidant and dopant through a very simple self-assembly process. The structure characterizations by elemental analysis, XPS and FTIR demonstrated that APS is served as both oxidant and dopant due to the proton acid produced during polymerization, which is proven by the decreasing pH value of the reaction solution along with the increase of polymerization time. Besides, the influences of the alkyl-substitution position on the molecular structure, polymerization process, morphology and electrical properties are also discussed.

CHARACTERIZATION OF BRUCITE/TiO2 COMPOSITE PARTICLE MATERIAL PREPARED BY MECHANO-CHEMICAL METHOD

2018 ◽  
Vol 25 (04) ◽  
pp. 1850085 ◽  
Author(s):  
YU LIANG ◽  
HAO DING ◽  
QIANG XUE
Keyword(s):  
Titanium Dioxide ◽  
Electron Microscope ◽  
Reaction Mechanism ◽  
Chemical Method ◽  
Composite Particle ◽  
Composite Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Brucite/TiO2 composite particle was prepared with Titanium dioxide (TiO2), coating on brucite particles’ surfaces by mechano-chemical method. X-ray diffraction (XRD), scanning electron microscope (SEM) and infrared spectra were used to investigate the microstructures, morphologies of the composite and the reaction mechanism. The results show that the ground extent of brucite as well as the mixed particles of brucite and TiO2 should keep at a suitable state. The hiding power and whiteness of the composite particles are 17.24[Formula: see text]g/m2 and 96.88%, respectively, presenting its similarity to TiO2 in pigment properties. TiO2 coats evenly on the surfaces of brucite through surface dehydroxylation reaction during mechano-chemical method.

Chemical Reaction Mechanism of Sintering Flue Gas Desulphurization with Pyrolusite Slurry

2011 ◽  
Vol 287-290 ◽  
pp. 2937-2940
Author(s):  
Yong Liang Gui ◽  
Qi Cao Yan ◽  
Ya Kun Yan ◽  
Chun Yan Song
Keyword(s):  
Reaction Mechanism ◽  
Chemical Reaction ◽  
Flue Gas ◽  
Ph Value ◽  
Reduction Reaction ◽  
Oxidation Reduction ◽  
Chemical Reaction Mechanism ◽  
Oxidation Reduction Reaction ◽  
Reaction Speed ◽  
Flue Gas Desulphurization

With the beginning of the characteristics of sintering flue gas, the thermodynamics and chemical reaction mechanism of sintering flue gas desulphurization with pyrolusite slurry were analyzed and discussed in the paper. Results shown that the main chemical reaction was oxidation-reduction reaction of sulfur dioxide and manganese dioxide with a high reaction velocity and desulphurization efficiency at the first stage. The reaction speed and the desulphurization efficiency decreased gradually and Mn2+is used as catalyst in the desulphurization reaction with the proceeding of chemical reaction and decreasing of PH value of solution.

Preparation and Characterization of Cu Nano-Powders by Hydrothermal Decomposition and Hydrogen Reduction Process

2010 ◽  
Vol 160-162 ◽  
pp. 456-459 ◽  
Author(s):  
Zai Yuan Li ◽  
Yun Gao ◽  
Duo Jin ◽  
Jie Liu ◽  
Yu Chun Zhai
Keyword(s):  
Hydrogen Reduction ◽  
Ph Value ◽  
Raw Materials ◽  
Reduction Process ◽  
Powder Size ◽  
Reaction Conditions ◽  
Nano Powder ◽  
Circular System ◽  
Reaction Speed

In this paper, Cu nano-powder was used to reduce CuO nano-powder by hydrogen reduction process, which was prepared by hydrothermal decomposition method taken CuSO4•5H2O and NaOH as raw materials. The reaction conditions of CuO nano-stick were that concentration of CuSO4 liquor was 0.1mol•L-1, concentration of NaOH liquor was 5mol•L-1, dropping speed was 50ml•min-1, pH value of reacting terminal was 12, stirring speed was 1200 r•min-1, reacting temperature was 60°C, reacting time was 30min. The CuO stick longness was 200nm, diameter was 30nm. The reaction conditions of CuO nano-boll were that dropping speed was 50ml•min-1, pH value of reacting terminal was 7, stirring speed 100 r•min-1, reacting temperature was 80°C, reacting time 30min. The diameter of CuO nano-ball was 50~100 nm. The Cu powder was prepared with materials CuO tick by hydrogen reduction in closed circular system. The higher the temperature, the reaction speed is faster. Hydrogen reduction time was 400s in reacting temperature 240°C. The Cu powder’ size was less than 100nm.

scholarly journals Microscopic Image Segmentation and Morphological Characterization of Novel Chitosan/Silica Nanoparticle/Nisin Films Using Antimicrobial Technique for Blueberry Preservation

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 303
Author(s):  
Rokayya Sami ◽  
Schahrazad Soltane ◽  
Mahmoud Helal
Keyword(s):  
Ph Value ◽  
Silica Nanoparticle ◽  
Morphological Characterization ◽  
Aerobic Bacteria ◽  
Nano Materials ◽  
Elongation At Break ◽  
Stable Suspension ◽  
Average Size ◽  
Material Ductility

In the current work, the characterization of novel chitosan/silica nanoparticle/nisin films with the addition of nisin as an antimicrobial technique for blueberry preservation during storage is investigated. Chitosan/Silica Nanoparticle/N (CH-SN-N) films presented a stable suspension as the surface loads (45.9 mV) and the distribution was considered broad (0.62). The result shows that the pH value was increased gradually with the addition of nisin to 4.12, while the turbidity was the highest at 0.39. The content of the insoluble matter and contact angle were the highest for the Chitosan/Silica Nanoparticle (CH-SN) film at 5.68%. The use of nano-materials in chitosan films decreased the material ductility, reduced the tensile strength and elongation-at-break of the membrane. The coated blueberries with Chitosan/Silica Nanoparticle/N films reported the lowest microbial contamination counts at 2.82 log CFU/g followed by Chitosan/Silica Nanoparticle at 3.73 and 3.58 log CFU/g for the aerobic bacteria, molds, and yeasts population, respectively. It was observed that (CH) film extracted 94 regions with an average size of 449.10, at the same time (CH-SN) film extracted 169 regions with an average size of 130.53. The (CH-SN-N) film presented the best result at 5.19%. It could be observed that the size of the total region of the fruit for the (CH) case was the smallest (1663 pixels), which implied that the fruit lost moisture content. As a conclusion, (CH-SN-N) film is recommended for blueberry preservation to prolong the shelf-life during storage.

Preparing Process and Properties of Collagen Modified Cotton Fiber

2011 ◽  
Vol 236-238 ◽  
pp. 1415-1419 ◽  
Author(s):  
Yun Hui Xu ◽  
Zhao Fang Du
Keyword(s):  
Cotton Fiber ◽  
Treatment Time ◽  
Ph Value ◽  
Periodate Oxidation ◽  
Aqueous Acetic Acid ◽  
Collagen Concentration ◽  
Acid Media ◽  
Xps Characterization ◽  
Aldehyde Groups

In order to develop cotton fabric underwear with the health care function, the cotton fiber was modified with the collagen (CMCF) using periodate oxidation method. The aldehyde groups on the glucose chains of the oxidized cotton cellulose were reacted with the amino groups of collagen to obtain the CMCF, and the oxidized cellulose was crosslinked with collagen in aqueous acetic acid media. The effects of collagen concentration, treatment time, reaction temperature, pH value of solution and periodate concentration on the amount of collagen crosslinked on cotton fiber were respectively discussed, and the optimal reaction technology was obtained. XPS characterization of the modified cotton fiber showed a characteristic peak about 400.0–405.0 eV corresponding to collagen, which indicated that the collagen was combined on the surface of cotton fiber. The mechanical properties of the collagen modified cotton fiber were improved. The resulting CMCF is a new natural ecological fiber and has the extensive application as a carrier for the controlled release of drugs.

scholarly journals Preparation and Characterization of Magnetic Chitosan Microcapsules

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaopeng Xiong ◽  
Yong Wang ◽  
Weiwei Zou ◽  
Jiangjiang Duan ◽  
Yun Chen
Keyword(s):  
Magnetic Properties ◽  
Strong Interaction ◽  
Liquid Paraffin ◽  
Hollow Microspheres ◽  
Composite Particles ◽  
Cross Link ◽  
Magnetic Chitosan ◽  
Starting Solution ◽  
Dense Shell

By dispersing aqueous precipitant in liquid paraffin to prepare a W/O emulsion then adding chitosan (CS) solution, CS microcapsules have been successfully prepared. It is a facile way to prepare polymer microcapsules by using aqueous precipitant or nonsolvent as template, which avoids the removal of template and would free from the necessity to cross-link the microcapsule as usual methods to directly form dense shell. The hollow feature of the obtained materials is revealed. The diameter of the microcapsules ranges from severalμm to over 100 μm. Magnetic CS microcapsules have been prepared in this way when Fe3+and Fe2+were mixed with CS to prepare a mixture starting solution. The appearance and microstructure of the composite microcapsules were studied. The results indicate that the formed Fe3O4nanoparticles are embedded in the CS matrix evenly due to strong interaction between the Fe3O4nanoparticles and the CS molecules. The Fe3O4content and the magnetic properties of the composite microcapsule were measured. The composite microcapsules were calcined in air at 700°C to prepare pure inorganic hollow microspheres. It is general to prepare hollow polymeric or composite particles by using this method.

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