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Abstract  

The objective of this study is to evaluate the use of titanium dioxide nanoparticles which were prepared by novel sonochemical method as an ion exchange material for the removal of Sr from aqueous solution. The pH effect on the Sr2+ sorption was investigated. The data obtained have been correlated with Freundlich, Temkin and Dubinin–Radushkevich (D–R) isotherm models. Thermodynamic parameters fort he sorption system have been determined at four temperatures. Simple kinetic models have been applied to the rate and isotherm sorption data and the relevant kinetic parameters were determined from the graphical presentation of these models at 298°K. Results explained that the pseudo second-order sorption mechanism is predominant and the overall rate constant of sorption process appears to be controlled by chemical sorption process. The value of sorption energy E = 13 kJ/mol at 298°K and the value of Gibbs free energy ∆G° = 3,222 kJ/mol at 298°K prove that the sorption of strontium on titanium dioxide nanoparticles is an endothermic and non-spontaneous process.

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Abstract

Ba10−xCsx(PO4)6Cl2, (x = 0, 0.5) chloroapatite ceramics were prepared by sonochemical method of synthesis. The measured room temperature lattice parameters of Ba10 (PO4)6Cl2 and Ba9.5Cs0.5 (PO4)6Cl2−δ are practically the same; that is, a = 10.26 (8), c = 7.65 (7) and a = 10.27 (7), c = 7.65 (5), respectively. Heat capacity measurements were carried out on these materials by differential scanning calorimetry (DSC) in the temperature range 298–800 K. The heat capacity values of Ba9.5Cs0.5(PO4)6Cl2−δ are found to be slightly higher at all temperatures than those of Ba10(PO4)6Cl2. From the heat capacity data, other thermodynamic functions such as enthalpy and entropy increments were computed. The heat capacity values of Ba10(PO4)6Cl2 and Ba9.5Cs0.5(PO4)6Cl2−δ at 298 K are 0.3912 and 0.4310 J K−1 g−1, respectively. Thermal expansion property of the doped and undoped barium chloroapatites was measured by using a home built dilatometer which uses LVDT as displacement sensor. The bulk thermal expansion of Ba10(PO4)Cl2 and Ba9.5Cs0.5(PO4)Cl2−δ is observed to be about 0.9% in the temperature range of 298–973 K.

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combustion method [ 15 ], sonochemical method under ambient air [ 6 , 16 ], hydrothermal and microwave-assisted hydrothermal method [ 6 , 17 , 18 ], and via a sol–gel route [ 19 ]. This work involved the synthesis of Ce 1− x O 2 –M x O (M = Cu, Co

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. 3. Jugović , D , Mitrić , M , Cvjetićanin , N , Jančar , B , Mentus , S , Uskoković , D . 2008 . Synthesis and characterization of LiFePO 4 /C composite obtained by sonochemical method . J Solid

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Reaction Kinetics, Mechanisms and Catalysis
Authors: A. Martínez-de la Cruz, D. B. Hernández-Uresti, Leticia M. Torres-Martínez, and S. W. Lee

photocatalyst under UV irradiation. Recently, the synthesis of PbMoO 4 was reported by several techniques, such as chemical precipitation, solvothermal, microwave irradiation, and sonochemical methods [ 9 – 14 ]. Nevertheless, according to our best knowledge

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, Thongtem , S . 2010 Analysis of lead molybdate and lead tungstate synthesized by a sonochemical method . Curr Appl Phys. 10 : 342 – 345 . 10.1016/j.cap.2009.06.024 . 28. Mackenzie , JD

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Preparation of nanoparticles of oxides by the citrate–nitrate process

Effect of metal ions on the thermal decomposition characteristics

Journal of Thermal Analysis and Calorimetry
Authors: S. Banerjee, A. Kumar, and P. Sujatha Devi

.1023/A:1004895605613 . 3. Liang , J , Jiang , X , Liu , G , Deng , Z , Zhuang , J , Li , F , Li , Y . Characterization and synthesis of pure ZrO 2 nanopowders via sonochemical

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