Aqueous Solution Synthesis of Cd(OH)2 Hollow Microspheres via Ostwald Ripening and Their Conversion to CdO Hollow Microspheres

2008 ◽  
Vol 112 (37) ◽  
pp. 14360-14366 ◽  
Author(s):  
Wen-Shou Wang ◽  
Liang Zhen ◽  
Cheng-Yan Xu ◽  
Wen-Zhu Shao
Keyword(s):  
Aqueous Solution ◽  
Ostwald Ripening ◽  
Hollow Microspheres ◽  
Solution Synthesis

Aqueous Solution Synthesis of CaF2 Hollow Microspheres via the Ostwald Ripening Process at Room Temperature

2009 ◽  
Vol 1 (4) ◽  
pp. 780-788 ◽  
Author(s):  
Wen-Shou Wang ◽  
Liang Zhen ◽  
Cheng-Yan Xu ◽  
Jun-Zhou Chen ◽  
Wen-Zhu Shao
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Ostwald Ripening ◽  
Hollow Microspheres ◽  
Solution Synthesis ◽  
Ripening Process

scholarly journals Long-Term Stability of Different Kinds of Gas Nanobubbles in Deionized and Salt Water

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1808
Author(s):  
Yali Zhou ◽  
Zhenyao Han ◽  
Chunlin He ◽  
Qin Feng ◽  
Kaituo Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Bubble Size ◽  
Ostwald Ripening ◽  
Salt Water ◽  
Dlvo Theory ◽  
Deionized Water ◽  
Hydrodynamic Cavitation ◽  
Term Stability ◽  
Long Term Stability

Nanobubbles have many potential applications depending on their types. The long-term stability of different gas nanobubbles is necessary to be studied considering their applications. In the present study, five kinds of nanobubbles (N2, O2, Ar + 8%H2, air and CO2) in deionized water and a salt aqueous solution were prepared by the hydrodynamic cavitation method. The mean size and zeta potential of the nanobubbles were measured by a light scattering system, while the pH and Eh of the nanobubble suspensions were measured as a function of time. The nanobubble stability was predicted and discussed by the total potential energies between two bubbles by the extended Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. The nanobubbles, except CO2, in deionized water showed a long-term stability for 60 days, while they were not stable in the 1 mM (milli mol/L) salt aqueous solution. During the 60 days, the bubble size gradually increased and decreased in deionized water. This size change was discussed by the Ostwald ripening effect coupled with the bubble interaction evaluated by the extended DLVO theory. On the other hand, CO2 nanobubbles in deionized water were not stable and disappeared after 5 days, while the CO2 nanobubbles in 1 mM of NaCl and CaCl2 aqueous solution became stable for 2 weeks. The floating and disappearing phenomena of nanobubbles were estimated and discussed by calculating the relationship between the terminal velocity of the floating bubble and bubble size.

Preparation of Triangular Silver Nanoparticles Using Polyvinyl Pyrrolidone with Different Concentration

2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Driving Force ◽  
Ostwald Ripening ◽  
Polyvinyl Pyrrolidone ◽  
Protective Agent ◽  
Ag Nps ◽  
Transmission Electron ◽  
Uv Visible

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.

Effect of Precipitation Method on Stoichiometry and Morphology of Hydroxyapatite Nanoparticles

2007 ◽  
Vol 330-332 ◽  
pp. 271-274 ◽  
Author(s):  
He Bin Shi ◽  
Hong Zhong ◽  
Yu Liu ◽  
Jin Yan Gu ◽  
Chang Sheng Yang
Keyword(s):  
Aqueous Solution ◽  
Crystal Size ◽  
Ostwald Ripening ◽  
Precursor Solution ◽  
Reaction Vessel ◽  
Reaction Process ◽  
Precipitation Method ◽  
Precipitation Reaction ◽  
Hydroxyapatite Nanoparticles ◽  
Coprecipitation Process

This paper reports synthesis of hydroxyapatite nanoparticles by three precipitation methods. Homogeneous aqueous solution of Ca(NO3)2 and H3PO4 was used as precursor solution, and NH3•H2O was precipitator. Calcium deficient hydroxyapatite nanorods were obtained by adding the precipitator into precursor solution, near stoichiometric hydroxyapatite nanoparticles were derived from adding precursor solution into the precipitator, and smaller hydroxyapatite nanoparticles were prepared by adding precipitator and precursor solution simultaneously into a reaction vessel. The stoichiometry of hydroxyapatite was mainly affected by pH at precipitation reaction process. The crystal size and shape of hydroxyapatite particles was related to Ostwald ripening. The stoichiometry and morphology of hydroxyapatite nanoparticles can be controllable by selecting suitable coprecipitation process.

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