文献类型：期刊文献

英文题名：Thermal dehydration kinetics of 4CaO.5B2O3.7H2O with different phases and morphologies

作者：Wu, Shiming Zhu, Fusheng Feng, Xiaoqin Zhang, Hongyan Zheng, Jia Huang, Hongsheng

第一作者：Wu, Shiming

通信作者：Huang, HS[1]|[144406c0812405d42e8a8]黄宏升;

机构：[1]Guizhou Inst Technol, Sch Chem Engn, Guiyang 550003, Peoples R China;[2]Key Lab Energy Chem Guizhou Univ, Guiyang 550003, Peoples R China

第一机构：贵州理工学院化学工程学院

通信机构：corresponding author), Guizhou Inst Technol, Sch Chem Engn, Guiyang 550003, Peoples R China.|贵州理工学院化学工程学院;贵州理工学院;

年份：2024

卷号：329

外文期刊名：JOURNAL OF SOLID STATE CHEMISTRY

收录：;EI(收录号：20234214904240);Scopus(收录号：2-s2.0-85173812290);WOS:【SCI-EXPANDED(收录号:WOS:001098671100001)】；

基金：This work is financially supported by the National Natural Science Foundation of China (No. 21963006) key laboratory of energy chemistry in guizhou universities (Qian Jiao Ji [2022] 035) and high level talent scientific research startup project of Guizhou Institute of Technology (XJGC20190614) .

语种：英文

外文关键词：Calcium borate; Thermal dehydration kinetics; Mechanism function

摘要：alpha-4CaO.5B2O3.7H2O (sheet-like structure) and three polymorphs of beta-4CaO.5B2O3.7H2O (flower-like, succulent plant-like and book-like structure) were prepared by hydrothermal method, and characterized by XRD, FTIR, TG-DTA-DTG, SEM. The activation energies (Ea) of the two-step thermal dehydration of 4CaO.5B2O3.7H2O with different morphologies and phases were calculated by Kissinger-Akahira-Sunoes (KAS) method. The most probable mechanism function of the two-step dehydration reaction was determined by Coats-Redfern (CR) method, and the average pre-exponential factor (A) of the two-step thermal dehydration of the sample was calculated. The results showed that the thermal dehydration of 4CaO.5B2O3.7H2O was divided into two steps. The activation energy of thermal dehydration reaction was affected by the phase, morphology and particle size. The activation energies of the two-step thermal dehydration of beta-4CaO.5B2O3.7H2O(flower-like, succulent plant-like and book-like structure) all decrease in turn, which is consistent with the change trend of particle size. The average pre-exponential factor of the first-step thermal dehydration of all samples is smaller than that of the second-step thermal dehydration. The mechanism functions of the first-step and second-step thermal dehydration stages are Jander equation [1-(1-alpha)1/3]2 and Z-L-T equation [(1-alpha)- 1/3-1]2, respectively, which belong to three-dimensional diffusion. The three-dimensional diffusion process of the two-step thermal dehydration was analyzed and explained.