Application of simplified version of advanced isoconversional procedure in non-isothermal kinetic study
- 194 Downloads
The single phase NH4Co0.9Zn0.1PO4·H2O was prepared via solid-state reaction at 80 °C. Based on a simplified version of advanced isoconversional procedure, the values of activation energy E α associated with the first, second, and third stages of the thermal decomposition of NH4Co0.9Zn0.1PO4·H2O were obtained, which demonstrates that the third stage is a kinetically complex process, and the first and second stages are single-step kinetic processes and can be described by a unique kinetic triplet [E α, A, and g(α)]. The most probable reaction mechanisms of the first two stages were estimated by the comparison between experimental plots and modeled results. The values of pre-exponential factor A of the two stages were obtained on the basis of E α and the reaction mechanisms. The distributed activation energy model was applied to study the third stage. Besides, some thermodynamic functions of transition state complexes (ΔS ≠, ΔH ≠, and ΔG ≠) of the two stages were also calculated.
KeywordsNH4Co0.9Zn0.1PO4·H2O Non-isothermal kinetics Thermodynamics Thermal decomposition Thermogravimetric analysis Solid-state reaction
This study was financially supported by the Key laboratory of new processing technology for nonferrous metals and materials, Ministry of Education, Guangxi University (No. GXKFZ-02); the Guangxi Natural Scientific Foundation of China (Grant Nos. 2012GXNSFAA053019 and 0991108); and the Guangxi Science and Technology Agency Research Item of China (Grant No. 0895002–9).
- 4.Harrison WTA, Sobolev AN, Phillip MLF. Hexagonal ammonium zinc phosphate, (NH4)ZnPO4, at 10 K. Acta Crystallogr. 2001;C57:508–9.Google Scholar
- 7.Harrison WTA. [H3N(CH2)3NH3]·0.5[ZnPO4], an organically templated zincophosphate analogue of the aluminosilicate zeolite edingtonite. Acta Crystallogr. 2001;E57:m248–50.Google Scholar
- 17.Braga RM, Barros JMF, Melo DMA, Melo MAF, Aquino FdeM, Freitas JCdeO, Santiago RC. Kinetic study of template removal of MCM-41 derived from rice husk ash. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2516-y.
- 22.He Y, Liao S, Chen ZP, Chai Q, Li Y, Su YY, Wu WW, Li B. Application of isoconversional calculation procedure to non-isothermal kinetics study. Part II. Thermal decomposition of NH4CuPO4·H2O. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2306-6.
- 33.Šesták J. Thermodynamical properties of solids. Prague: Academia; 1984.Google Scholar
- 34.Bamford CH, Tipper CFH. Comprehensive chemical kinetics, vol 22, reactions in the solid state. Amsterdam: Elsevier Science Publication; 1980.Google Scholar
- 35.Young D. Decomposition of solids. Oxford: Pergamon Press; 1966.Google Scholar