Kinetic approach of multi-step thermal decomposition processes of iron(III) phosphate dihydrate FePO4∙2H2O

Khachani, Mariam; Hamidi, Adnane El; Kacimi, Mohammed; Halim, Mohammed; Arsalane, Saı̈d

doi:10.1016/j.tca.2015.04.020

Cited by 40 publications

(24 citation statements)

References 36 publications

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“…The isoconversional analysis technique makes a compromise between the oversimplified single‐step Arrhenius method and the prevalent occurrence of processes whose kinetics is multistep and / or non‐Arrhenius . To date, kinetic parameters are best estimated by the isoconversional methods that allow the reaction model independent evaluation of the activation energy at various progressive degrees of conversion by conducting multiple experiments at different constant heating rates and hence highly recommended to estimate reliable kinetic description of the investigated thermal decomposition reaction process .…”

Section: Experimental and Analytical Methodsmentioning

confidence: 99%

“…where k ( T ) is the Arrhenius rate constant, f (α) is the differential conversion function , E is the activation energy, A is the reaction rate, and R is the universal gas constant. This temperature dependence is referred to as the Arrhenius equation.…”

Section: Introductionmentioning

confidence: 99%

“…Thermogravimetric (TG) analysis is a common method for obtaining conversion data from the thermal solid‐state reactions, which result in the change of sample mass upon heating under isothermal or nonisothermal conditions . Nonisothermal thermogravimetry with a linear heating rate is the most frequently used technique for thermal analysis of materials .…”

Section: Introductionmentioning

confidence: 99%

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Kinetic Analysis of Nonisothermal Decomposition of Acetyl Ferrocene

Das

Bhattacharjee

2018

Int J of Chemical Kinetics

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The work deals with thermal decomposition of acetyl ferrocene in nitrogen atmosphere based on nonisothermal thermogravimetry. It presents a mathematical analysis of nonisothermal thermogravimetric data using multiheating rates to estimate reaction kinetic parameters. Model free (integral isoconversional) methods are employed to analyze the thermogravimetric data. The decomposition is a multistep process. The activation energy Eα of decomposition is conversion (α) dependent. The average values of activation energy are Eα = 49.87, 106.28, and 183.35 kJ mol−1 for three major steps of decomposition. The most probable reaction mechanism function, g(α), for thermal reactions has been identified by the master plot method, and the stepwise reaction mechanisms are found to be different for different steps. The estimated values of the activation energy Eα and g(α) have been utilized in the determination of the reaction rate Aα of thermal decomposition. The α‐dependent reaction rate values are determined and are found to lie in the range of 5.2 × 105 to 3.2 × 104 min−1, 1.7 × 1015 to 7.8 × 106 min−1, and 3.8 × 108 to 1.4 × 107 min−1 for three different steps. Based on the values of Eα, g(α), and Aα, the thermodynamic triplets (ΔS, ΔH, ΔG) associated with the decomposition reactions have been estimated. Estimated kinetic parameters have been used to construct the conversion curves, and those have been successfully compared with the experimentally observed ones.

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Section: Experimental and Analytical Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Kinetic Analysis of Nonisothermal Decomposition of Acetyl Ferrocene

Das

Bhattacharjee

2018

Int J of Chemical Kinetics

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“…The Model-free method is regarded as more accurate for a multistep reaction and has the form of differential and integral variants [13]. Based on an isoconversional principle, the rate of conversion is defined as the function of temperature at a constant conversion degree [13,14]. The kinetic analysis of solid-state material in thermal decomposition can be expressed as Eq.…”

Section: Kinetic Studiesmentioning

confidence: 99%

“…The kinetic analysis of solid-state material in thermal decomposition can be expressed as Eq. (1) [13,[15][16][17] …”

Section: Kinetic Studiesmentioning

confidence: 99%

Investigation of the thermal decomposition kinetics of bezafibrate

Shen

Zhou

2016

J Therm Anal Calorim

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The thermal decomposition kinetics of bezafibrate in a nitrogen atmosphere has been investigated by analyzer DTG-60. The thermal behavior of bezafibrate at the different heating rates 4, 8, 12, 16 and 20°C min -1 displays two-stage decomposition processes among 500-650 K. The activation energy (E) and pre-exponential factor (A) were calculated to be 128.72 kJ mol -1 and 3.56 9 10 10 min -1 by Flynn-Wall-Ozawa, KissingerAkahira-Sunose, Doyle, Kissinger and Šatava-Š esták methods for the second-stage decomposition process. The results show that the non-isothermal thermal decomposition mechanism of bezafibrate is classified as three-dimensional diffusion model, and the integral and differential equations are gðaÞ ¼ ½1 À ð1 À aÞ 1=3 2 and f ðaÞ ¼ 3 2 1 À a ð Þ 2=3The enthalpy (DH = ), entropy (DS = ) and Gibbs free energy (DG = ) were calculated to be 123.74 kJ mol -1 , -91.07 J mol -1 K -1 and 178.29 kJ mol -1 , respectively.Keywords Bezafibrate Á Kinetics Á Thermal decomposition Á Thermodynamical analysisList of symbols A Pre-exponential factor (min -1 ) E Activation energy (kJ mol -1 ) G = Gibbs free energy (kJ mol -1 )Einstein vibration frequency kBoltzmann constant (1.3807 9 10 -23 J K -1 ) hPlanck constant (6.625 9 10 -34 J s) t Time (s) T Absolute temperature (K) f (a) Differential form of kinetic mechanism function g (a) Integral form of kinetic mechanism functionGreek symbols a Conversion degree b Heating rate (K min -1 )

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pH‐Responsive itaconic acid‐based villous‐like hydrogels for water‐plugging materials

Xue,

He,

Jia

et al. 2024

J of Applied Polymer Sci

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The development of new methods to improve the water absorption performance of polymeric materials, taking into account their environmental friendliness, is a promising research direction in Itaconic acid based water‐absorbent polymeric materials. In this study, from the perspective of environmental protection, we propose to design highly absorbent hydrogels with a novel villous‐like structure by using hydrophilic itaconic acid as the raw material and combining it with a novel villous‐like network structure to substantially increase the contact area between the hydrogel and water, thus improving the water absorption rate of the hydrogel. Itaconic acid is water‐soluble and renewable. The widespread use of polymeric water‐absorbent polymers from traditional petroleum sources poses a serious threat to the sustainability of ecosystems, and therefore, itaconic acid has attracted much attention as an alternative to petroleum‐based polymers. The villous‐like network structure is inspired by the villi of the small intestine, the special presence of which expands the absorptive surface area of the small intestine by a factor of about 600, and it is therefore hypothesized that the introduction of this special structure could help the hydrogel to greatly increase the contact area with water and thus achieve the high water absorption properties of the hydrogel. This is also the first time that the villus‐like network structure has been applied to Itaconic acid based hydrogels. The results show that the hydrogel has the property of rapid water absorption and swelling and the water absorption rate of the hydrogel can reach up to 2210 g/g, and the villous‐like structure formed by the hydrogel can be observed in the SEM image. The water‐absorption test of the hydrogel showed that when the molar mass ratio of itaconic acid to acrylic acid was 1:4, the hydrogel absorbed water and swelled rapidly in a short time. The results of the water retention test showed that the hydrogel still existed after 5 days, and the water retention was greater than 86%. In addition, the hydrogel had high reusability, and the water absorption performance of the hydrogel could still reach 89.12% after 6 cycles of the water absorption test. Hydrogel with high water‐absorbing property has good application prospects as fast swelling material in the field of flood control of water conservancy projects.

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Kinetic approach of multi-step thermal decomposition processes of iron(III) phosphate dihydrate FePO4∙2H2O

Cited by 40 publications

References 36 publications

Kinetic Analysis of Nonisothermal Decomposition of Acetyl Ferrocene

Kinetic Analysis of Nonisothermal Decomposition of Acetyl Ferrocene

Investigation of the thermal decomposition kinetics of bezafibrate

pH‐Responsive itaconic acid‐based villous‐like hydrogels for water‐plugging materials

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