Facile synthesis of hydrotalcite and its thermal decomposition kinetics mechanism study with masterplots method

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• 作者：Qiwei Long^a ; Yao Xia^a ; Sen Liao^a ; ^{liaosen@gxu.edu.cn" class="auth_mail} ; ^{liaosen380@sina.com" class="auth_mail} ; ^{liaosen327@sina.com" class="auth_mail} ; ^{liaosen327@hotmail.com" class="auth_mail} ; Yu Li^a ; Wenwei Wu^a ; Yingheng Huang^a ; ^b
• 关键词：Hydrotalcite ; Kinetics ; Synthesis ; Thermal decomposition ; Mechanism ; Thermogravimetry
• 刊名：Thermochimica Acta
• 出版年：10 March, 2014
• 年：2014
• 卷：579
• 期：Complete
• 页码：50-55
• 全文大小：806 K

文摘

The hydrotalcite, Mg₄Al₂(OH)₁₂CO₃路3H₂O, was synthesized via low-heating solid-state reaction at 80 掳C. The thermal decomposition of Mg₄Al₂(OH)₁₂CO₃路3H₂O experienced two stages. The apparent activation energy E_a was estimated with Vyazovkin procedure. The average values of E_a associated with the two stages were determined to be 110.9 卤 10.3, 140.3 卤 4.2 kJ mol^鈭?, respectively, which the two stages are single-step kinetic processes. Masterplots and nonlinear methods were used to define the most probable reaction mechanisms of the two stages. The results show that the reaction mechanism functions of the two stages are as follows: (i) g(伪) = (1 鈭?#xA0;伪)^鈭? 鈭?#xA0;1, (ii) g(伪) = (1 鈭?#xA0;伪)^鈭?/2 鈭?#xA0;1, respectively. The values of pre-exponential factor A for the two stages were obtained on the basis of E_a and g(伪). Besides, some thermodynamic functions (螖S^#, 螖H^# and 螖G^#) of the transition state complexes for the two stages were also calculated.