Kinetics of the Heterogeneous Solid State Process

2013 ◽  
pp. 33-44
Author(s):  
Pritam Deb
Keyword(s):  
Solid State ◽  
State Process ◽  
Kinetics Of ◽  
Heterogeneous Solid

scholarly journals Ball Milling to Build the Hybrid Mesocrystals of Ibuprofen and Aragonite

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Kyoung A Cho ◽  
Insil Choi ◽  
Il Won Kim
Keyword(s):  
Calcium Carbonate ◽  
Solid State ◽  
Ball Milling ◽  
Release Kinetics ◽  
Drug Formulation ◽  
Controlling Factor ◽  
Release Behavior ◽  
State Process ◽  
The Stability ◽  
Kinetics Of

Mesocrystal formation is one of the new paradigms of the nonclassical crystallization, where the assembly of crystal domains is observed. Also, it has been recently employed in studies on drug formulation to utilize controlled dissolution of the drug domains. In this report, ibuprofen was attempted to form hybrid mesocrystals with calcium carbonate crystals. Two polymorphs of calcium carbonate (aragonite and calcite) were used during the solid-state process of ball milling. Structural analyses confirmed the mesocrystal formation of ibuprofen with aragonite but not with calcite. The origin of the observed behavior was found from the higher affinity of ibuprofen to aragonite, especially its (0 1 0) surface, compared to calcite. The hybrid mesocrystals of ibuprofen and aragonite showed the environment-responsive release behavior, where the stability of aragonite was the controlling factor for the release kinetics of ibuprofen.

Investigation of Optical and electrical conduction mechanism of AgYP2O7 prepared by solid state process

2021 ◽  
pp. 111444
Author(s):  
N. Weslati ◽  
I. Gharbi ◽  
M. Hamdi ◽  
A. Oueslati ◽  
M. Gargouri ◽  
...  
Keyword(s):  
Solid State ◽  
Electrical Conduction ◽  
Conduction Mechanism ◽  
Electrical Conduction Mechanism ◽  
State Process

scholarly journals Solid-State Redox Kinetics of CeO2 in Two-Step Solar CH4 Partial Oxidation and Thermochemical CO2 Conversion

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 723
Author(s):  
Mahesh Muraleedharan Nair ◽  
Stéphane Abanades
Keyword(s):  
Solid State ◽  
Solar Energy ◽  
Kinetic Models ◽  
Oxygen Carrier ◽  
Co2 Conversion ◽  
Oxidation Reactions ◽  
Redox Kinetics ◽  
Concentrated Solar Energy ◽  
Ceria Reduction ◽  
Kinetics Of

The CeO2/CeO2−δ redox system occupies a unique position as an oxygen carrier in chemical looping processes for producing solar fuels, using concentrated solar energy. The two-step thermochemical ceria-based cycle for the production of synthesis gas from methane and solar energy, followed by CO2 splitting, was considered in this work. This topic concerns one of the emerging and most promising processes for the recycling and valorization of anthropogenic greenhouse gas emissions. The development of redox-active catalysts with enhanced efficiency for solar thermochemical fuel production and CO2 conversion is a highly demanding and challenging topic. The determination of redox reaction kinetics is crucial for process design and optimization. In this study, the solid-state redox kinetics of CeO2 in the two-step process with CH4 as the reducing agent and CO2 as the oxidizing agent was investigated in an original prototype solar thermogravimetric reactor equipped with a parabolic dish solar concentrator. In particular, the ceria reduction and re-oxidation reactions were carried out under isothermal conditions. Several solid-state kinetic models based on reaction order, nucleation, shrinking core, and diffusion were utilized for deducing the reaction mechanisms. It was observed that both ceria reduction with CH4 and re-oxidation with CO2 were best represented by a 2D nucleation and nuclei growth model under the applied conditions. The kinetic models exhibiting the best agreement with the experimental reaction data were used to estimate the kinetic parameters. The values of apparent activation energies (~80 kJ·mol−1 for reduction and ~10 kJ·mol−1 for re-oxidation) and pre-exponential factors (~2–9 s−1 for reduction and ~123–253 s−1 for re-oxidation) were obtained from the Arrhenius plots.

Effect of praseodymium on the solid-state oxidation kinetics of an AMg2 alloy

2015 ◽  
Vol 2015 (7) ◽  
pp. 521-524 ◽  
Author(s):  
N. F. Ibrokhimov ◽  
I. N. Ganiev ◽  
A. E. Berdiev ◽  
N. I. Ganieva
Keyword(s):  
Solid State ◽  
Oxidation Kinetics ◽  
Kinetics Of
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