Effect of Polyvinylpyrrolidone Ratio on Synthesis of High Concentration Nano-Silver Colloid

2012 ◽  
Vol 466-467 ◽  
pp. 381-385
Author(s):  
Wei Wei Li ◽  
Lu Hai Li ◽  
Li Xin Mo ◽  
Ji Lan Fu
Keyword(s):  
Particle Size ◽  
Silver Nitrate ◽  
Average Particle Size ◽  
Thermo Gravimetric Analysis ◽  
Molar Ratio ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
Silver Colloid ◽  
High Concentration ◽  
Nano Silver

Conductive ink, especially the nano-silver ink is becoming more and more popular in printable electronic field. In order to synthesize high concentration, stable nano-silver colloid, liquid chemical reduction is used and different ratios of PVP to silver nitrate are studied. After precise adjustments of the parameters, colloid with silver content of wt7.8% is obtained. Particle size distribution, UV-Vis spectra, thermo gravimetric analysis and SEM images are conducted to characterize the silver particles. The results show that when molar ratio of PVP to silver nitrate is 0.6, the average particle size is 170nm and some deposit can be seen, while the ratio increases to 1.5, the size decreases to 68nm, and the residue quality of the silver colloid showed in the TG analysis is 7.88%. After aging for 1 month, the colloid is still stable and the color keeps to the original dark green. When the ratio continues increasing to 2.5, particle size becomes 112nm and some larger particles beyond 3μm can be observed.

Fe3O4 Magnetic Preparation by Bauxite Ore Washing Fine Mud

2014 ◽  
Vol 1010-1012 ◽  
pp. 961-965
Author(s):  
Jian Qiang Xiao ◽  
Guo Wei He ◽  
Yan Jin Hu
Keyword(s):  
Particle Size ◽  
Aging Time ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Test Methods ◽  
Raw Material ◽  
Molar Ratio ◽  
Average Particle ◽  
Experimental Conditions ◽  
Particle Size Analyzer

Bauxite waste sludge as a raw material, the use of reverse chemical coprecipitation synthesize Fe3O4. Researching temperature, precipitation concentration, aging time and Fe2+/Fe3+ molar ratio effect on the particle size, morphology. Optimal experimental conditions: temperature 70 °C, the precipitant NaOH mass ratio of 10%, aging time 3h, Fe2+/Fe3+ molar ratio of 2:3. Test methods using a laser particle size analyzer, XRD analysis of the products were characterized, the product is Fe3O4, the average particle size of 0.11mm.

Low Temperature Hydrothermal Synthesis of Nanophase BaTiO3 and BaFe12O19 Powders

1996 ◽  
Vol 457 ◽  
Author(s):  
Fatih Dogan ◽  
Shawn O'rourke ◽  
Mao-Xu Qian ◽  
Mehmet Sarikaya
Keyword(s):  
Particle Size ◽  
Hydrothermal Reaction ◽  
Average Particle Size ◽  
Reaction Times ◽  
Nanocrystalline Powders ◽  
Molar Ratio ◽  
Average Particle ◽  
Hydrothermal Conditions ◽  
Processing Variables ◽  
Xrd And Tem

ABSTRACTNanocrystalline powders with an average particle size of 50 nm has been synthesized in two materials systems under hydrothermal conditions below 100°C. Processing variables, such as temperature, concentration and molar ratio of reactants and reaction time were optimized to obtain particles of reduced size and stoichiometric compositions. Hydrothermal reaction takes place between Ba(OH)2 solution and titanium/iron precursors in sealed polyethylene bottles in the BaTiO3 and BaFe12O19 systems, respectively. While crystalline BaTiO3 forms relatively fast within a few hours, formation of fully crystalline and stoichiometric BaFei20i9 require considerably longer reaction times up to several weeks and strongly dependent on the Ba:Fe ratio of the precursors. The structural and compositional evaluation of the nanophase powders were studied by XRD and TEM techniques.

Biosynthesis and Characterization of Copper Nanoparticles Using a Bioflocculant Extracted from Alcaligenis faecalis HCB2

2019 ◽  
Vol 11 (11) ◽  
pp. 1064-1070 ◽  
Author(s):  
Nkosinathi G. Dlamini ◽  
Albertus K. Basson ◽  
V. S. R. Rajasekhar Pullabhotla
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Copper Nanoparticles ◽  
Average Particle Size ◽  
Thermo Gravimetric Analysis ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir

Bioflocculant from Alcaligenis faecalis HCB2 was used in the eco-friendly synthesis of the copper nanoparticles. Nanoparticles were characterized using a scanning electron microscope (SEM), transmission electron microscopy (TEM), UV-visible spectroscopy, thermo gravimetric analysis (TGA) and Fourier Transform Infrared Spectroscopy (FT-IR). The transmission electron microscopy images showed close to spherical shapes with an average particle size of ∼53 nm. Energy-dispersive X-ray spectroscopy analysis confirmed the presence of the Cu nanopartilces and also the other elements such as O, C, P, Ca, Cl, Na, K, Mg, and S originated from the bioflocculant. FT-IR results showed the presence of the –OH and –NH2 groups, aliphatic bonds, amide and Cu–O bonds. Powder X-ray diffraction peaks confirmed the presence of (111) and (220) planes of fcc structure at 2 of 33° and 47° respectively with no other impurity peaks.

Effect of Synthetic Technology on the Properties of Co2O3 Powder

2018 ◽  
Vol 281 ◽  
pp. 46-51
Author(s):  
Ge Xiong ◽  
Hui Min Sun ◽  
Xue Yang ◽  
Jin Shi Li ◽  
Mei Hua Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Salt Solution ◽  
Average Particle Size ◽  
Particle Aggregation ◽  
Molar Ratio ◽  
Average Particle

Ultrafine Co2O3powder was prepared via hydrothermal synthesis. The effect of technology on the performance of the superfine Co2O3powders was investigated, and the hydrothermal parameters in preparing Co2O3were gradually improved. In addition, the morphology and grain size of the Co2O3powder were analyzed by FESEM. Results show that reducing the salt–alkali molar ratio resulted in more uniform Co2O3powder and smaller particles, with average particle size of approximately 40 nm. Reaction time displayed little effect on the Co2O3powder, but the particle size decreased with the reaction time. The concentration of salt solution remarkably affected the morphology of the Co2O3powder. Lower concentration resulted in smaller particle aggregation and particle size.

Effect of Ascorbic Acid and Particle Size on Iron Absorption from Ferric Pyrophosphate in Adult Women

2004 ◽  
Vol 74 (4) ◽  
pp. 294-300 ◽  
Author(s):  
Fidler ◽  
Davidsson ◽  
Zeder ◽  
Walczyk ◽  
Marti ◽  
...  
Keyword(s):  
Particle Size ◽  
Ascorbic Acid ◽  
Iron Absorption ◽  
Average Particle Size ◽  
Relative Bioavailability ◽  
Molar Ratio ◽  
Average Particle ◽  
Adult Women ◽  
Mean Particle Size ◽  
Ferric Pyrophosphate

The effects of added ascorbic acid and particle size on iron absorption from ferric pyrophosphate were evaluated in adult women (9–10 women/study) based on erythrocyte incorporation of iron stable isotopes (57Fe or 58Fe) 14 days after administration. Three separate studies were made with test meals of iron-fortified infant cereal (5 mg iron/meal) and the results are presented as geometric means and relative bioavailability values (RBV, FeSO4 = 100%). The results of study 1 showed that iron absorption was significantly lower from ferric pyrophosphate (mean particle size 8.5 mum) than from FeSO4 in meals without ascorbic acid (0.9 vs. 2.6%, p < 0.0001, RBV 36%) and in the same meals with ascorbic acid added at a 4:1 molar ratio relative to fortification iron (2.3 vs. 9.7%, p < 0.0001, RBV 23%). Ascorbic acid increased iron absorption from ferric pyrophosphate slightly less (2.6-fold) than from FeSO4 (3.7-fold) (p < 0.05). In studies 2 and 3, RBV of ferric pyrophosphate with an average particle size of 6.7 mum and 12.5 mum was not significantly different at 52 and 42% (p > 0.05), respectively. In conclusion, the addition of ascorbic acid increased fractional iron absorption from ferric pyrophosphate significantly, but to a lesser extent than from FeSO4. Decreasing the mean particle size to 6.7 mum did not significantly increase iron absorption from ferric pyrophosphate.

Microwave Assisted Preparation of YAG and Yb:YAG Transparent Ceramic Nanopowders for Laser Crystal

2016 ◽  
Vol 697 ◽  
pp. 76-79 ◽  
Author(s):  
Wei Si ◽  
Cang Xiong ◽  
Yi Wen Jiang ◽  
Zhi Feng Xing ◽  
Wei Pan
Keyword(s):  
Microwave Radiation ◽  
Laser Crystal ◽  
Radiation Power ◽  
Average Particle Size ◽  
Thermo Gravimetric Analysis ◽  
Transparent Ceramic ◽  
Precipitation Method ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
Microwave Assisted

YAG and Yb:YAG transparent ceramic nanopowders for laser crystal were synthesized by microwave-assisted alkoxide hydrolysis precipitation method. The YAG and Yb:YAG nanopowders were characterized by differential thermal analysis and thermo gravimetric analysis (DTA-TG), infrared spectrum (IR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and photoluminescence (PL) spectrum. The results show that the crystallizing temperature of the precursor of YAG and Yb:YAG is about 930 °C. The pure phase YAG and Yb:YAG nanopowders can be obtained at microwave radiation power of 385 W, microwave radiation time of 30 min and sintering temperature of 1100 °C. The average particle size of YAG is about 120 nm. Yb:YAG is uniform sphere and the average sizes is about 100 nm. The intensity of luminescence of Yb:YAG nanopowders decreased with the increasing of microware time. The maximum luminous intensity of the Yb:YAG nanopowders can be obtained when the microwave radiation is 30 min.

scholarly journals Synthesis of Cu2ZnSnS4 (CZTS) Ink by an Easy Hydrothermal Method

2021 ◽  
Author(s):  
Mahnaz Karbassi ◽  
Saeid Baghshahi ◽  
Nastaran Riahi-Noori ◽  
Roozbeh Siavash Moakhar
Keyword(s):  
Copper Acetate ◽  
Average Particle Size ◽  
Thermo Gravimetric Analysis ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
Tin Chloride ◽  
Vis Spectroscopy ◽  
Czts Nanoparticles

Abstract The quadrilateral p-type semiconductor Cu2ZnSnS4 (CZTS) with a direct bandgap of 1.4 to 1.5 eV and a high absorption coefficient in the visible light range, is considered an excellent absorbent layer in the production of solar cells. The application of Cu2ZnSnS4 film absorbent materials is promising in the field of low-cost solar cell production. In this paper, a simple, efficient, controllable, and inexpensive solvothermal method is used to make the CZTS nanoparticles from zinc acetate, copper acetate, tin chloride, thiourea, and hexadecyl amine solvent. The ink was prepared from the CZTS powder and applied by the doctor Blade technique on soda-lime glass. The X-ray diffraction (XRD) and Raman spectroscopy analysis showed that the CZTS synthesis nanoparticles had a pure Kesterite structure. The thermo-gravimetric analysis showed about 12% of the loss weight of CZTS nanoparticles using field emission scanning electron microscopy, energy dispersive spectroscopy, dynamic light scattering, and zeta potential indicated that the synthesized nanoparticles had a strong absorption in the range of 125–477 nm with an average particle size of 300 nm and plate shape. The energy bandgap of CZTS nanoparticles was measured to be 1.49 eV using UV-Vis spectroscopy.

Synthesis of Lanthanum Nickelate and Praseodymium Substituted Compounds by Molten Salt Technique

2011 ◽  
Vol 699 ◽  
pp. 67-78 ◽  
Author(s):  
S. Ignatius Arockiam ◽  
L. John Berchmans ◽  
S. Angappan ◽  
A. Visuvasam ◽  
V. Mani
Keyword(s):  
Molten Salt ◽  
Parent Compound ◽  
Average Particle Size ◽  
Thermo Gravimetric Analysis ◽  
Lone Pair ◽  
Rhombohedral Structure ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
Absorption Bands ◽  
Lanthanum Nickelate

Lanthanum Nickelate (LaNiO3) and Praseodymium (Pr) substituted compounds were prepared by molten flux method using chloride precursors. The investigation presents the characterization of the synthesized materials using TGA/DTA, XRD, FTIR, CHNS, EDAX, UV-visible, EPR spectral and SEM studies. The thermo gravimetric analysis reveals the decomposition and thermal reactions of the precursors at different temperature regions. The XRD analysis shows that the synthesized crystals have the rhombohedral structure. FTIR spectra exhibit the absorption bands for the O-H stretching vibration and Ni-O bands at different wave lengths. A shift in band position has been observed on the substitution of Pr3+ions in the parent compound. The CHNS analysis presents the impurities level in the synthesized compounds. The EDAX analysis shows the concentration of La, Ni, Pr and O in the synthesized compounds. The band gap of the material has been determined from UV spectra and it is found to be 4.96 eV for the parent compound. The lone pair of electron state is identified from the EPR spectra. The SEM micrographs have shown the presence of fine crystallites with irregular morphology. The average particle size of the powders is ranging between 25-35 μm. From the above studies, it has been concluded that pure crystals of LaNiO3and Praseodymium substituted compounds can be conveniently synthesized by molten salt technique.

scholarly journals Third-Generation Cephalosporin-Loaded Chitosan Used to Limit Microorganisms Resistance

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4792
Author(s):  
Letiția Doina Duceac ◽  
Gabriela Calin ◽  
Lucian Eva ◽  
Constantin Marcu ◽  
Elena Roxana Bogdan Goroftei ◽  
...  
Keyword(s):  
Particle Size ◽  
Antibiotic Resistance ◽  
Zeta Potential ◽  
Average Particle Size ◽  
Chitosan Nanoparticles ◽  
World Health ◽  
Multi Drug Resistance ◽  
Prolonged Release ◽  
Average Particle ◽  
Gravimetric Analysis

From their discovery, antibiotics have significantly improved clinical treatments of infections, thus leading to diminishing morbidity and mortality in critical care patients, as well as surgical, transplant and other types of medical procedures. In contemporary medicine, a significant debate regarding the development of multi-drug resistance involves all types of pathogens, especially in acute care hospitals due to suboptimal or inappropriate therapy. The possibility of nanotechnology using nanoparticles as matrices to encapsulate a lot of active molecules should increase drug efficacy, limit adverse effects and be an alternative helping to combat antibiotic resistance. The major aim of this study was to obtain and to analyze physico-chemical features of chitosan used as a drug-delivery system in order to stop the antibiotic resistance of different pathogens. It is well known that World Health Organization stated that multidrug resistance is one of the most important health threats worldwide. In last few years, nano-medicine emerged as an improved therapy to combat antibiotic-resistant infections agents. This work relies on enhancement of the antimicrobial efficiency of ceftriaxone against gram(+) and gram(−) bacteria by antibiotic encapsulation into chitosan nanoparticles. Physicochemical features of ceftriaxone-loaded polymer nanoparticles were investigated by particle size distribution and zeta potential, Fourier-transform infrared spectroscopy (FTIR), Thermal Gravimetric Analysis (TG/TGA), Scanning Electron Microscopy (SEM) characteristics techniques. The obtained results revealed an average particle size of 250 nm and a zeta potential value of 38.5 mV. The release profile indicates an incipient drug deliverance of almost 15%, after 2 h of approximately 83%, followed by a slowed drug release up to 24 h. Characteristics peaks of chitosan were confirmed by FTIR spectra indicating a similar structure in the case of ceftriaxone-loaded chitosan nanoparticles. A good encapsulation of the antibiotic into chitosan nanoparticles was also provided by thermo-gravimetric analysis. Morphological characteristics shown by SEM micrographs exhibit spherical nanoparticles of 30–250 nm in size with agglomerated architectures. Chitosan, a natural polymer which is used to load different drugs, provides sustained and prolonged release of antibiotics at a specific target by possessing antimicrobial activity against gram(+) and gram(−) bacteria. In this research, ceftriaxone-loaded chitosan nanoparticles were investigated as a carrier in antibiotic delivery.

scholarly journals Improved biodiesel production from waste cooking oil with mixed methanol–ethanol using enhanced eggshell-derived CaO nano-catalyst

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yeshimebet Simeon Erchamo ◽  
Tadios Tesfaye Mamo ◽  
Getachew Adam Workneh ◽  
Yedilfana Setarge Mekonnen
Keyword(s):  
Particle Size ◽  
Low Cost ◽  
Average Particle Size ◽  
Waste Cooking Oil ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Average Particle ◽  
Cooking Oil ◽  
Nano Catalyst

AbstractIn this report, the utilization of mixed methanol–ethanol system for the production of biodiesel from waste cooking oil (WCO) using enhanced eggshell-derived calcium oxide (CaO) nano-catalyst was investigated. CaO nano-catalyst was produced by calcination of eggshell powder at 900 °C and followed by hydration-dehydration treatment to improve its catalytic activity. The particle size, morphology, and elemental composition of a catalyst were characterized by using XRD, SEM, and EDX techniques, respectively. After hydration-dehydration the shape of a catalyst was changed from a rod-like to honeycomb-like porous microstructure. Likewise, average particle size was reduced from 21.30 to 13.53 nm, as a result, its surface area increases. The main factors affecting the biodiesel yield were investigated, accordingly, an optimal biodiesel yield of 94% was obtained at 1:12 oil to methanol molar ratio, 2.5 wt% catalyst loading, 60 °C, and 120-min reaction time. A biodiesel yield of 88% was obtained using 6:6 equimolar ratio of methanol to ethanol, the yield even increased to 91% by increasing the catalyst loading to 3.5 wt%. Moreover, by slightly increasing the share of methanol in the mixture, at 8:4 ratio, the maximum biodiesel yield could reach 92%. Therefore, we suggest the utilization of methanol–ethanol mixture as a reactant and eggshell-derived CaO as a catalyst for enhanced conversion of WCO into biodiesel. It is a very promising approach for the development of low-cost and environmentally friendly technology. Properties of the biodiesel were also found in good agreement with the American (ASTM D6571) fuel standards.

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