Tian Congxue, Chen Hua
Panzhihua University, Panzhihua 617000, Sichuan, P. R. China.
ACS Omega. 2023 Sep 14;8(38):34826-34833. doi: 10.1021/acsomega.3c04035. eCollection 2023 Sep 26.
Using the industrial low-concentration TiOSO solution as the raw material, the hydrolysis kinetics and structural evolution of metatitanic acid was investigated. The samples were characterized by TiO content, XRD analysis, particle size distribution, FT-IR spectroscopy, Raman analysis, and HRTEM. The curves of hydrolysis yield showed type shape, and the hydrolysis process consisted of the induction period, rapid hydrolysis period, and mature period. The rapid hydrolysis period was the first-order reaction, and increasing of hydrolysis temperature would shorten the induction period and hydrolysis period while prolonging the mature period had an approximate linear positive correlation on the hydrolysis yield and hydrolysis rate. The actual hydrolysis yield at the graying point was consistent with the calculated hydrolysis yield. The calculated pre-exponential factor was 1.40 × 10 min and activation energy was of 147.6 kJ/mol. With the hydrolysis temperature increasing, the grain size increased, the lattice stress decreased, the average particle size of metatitanic acid decreased, and the sulfur content decreased, resulting from the growth and adjustment of crystals and colloidal particles. Also, the SO ions promoted the formation of anatase TiO crystals. The formation of the precipitated particles underwent processes such as gel, crystal growth, aggregation, and condensation.
以工业低浓度TiOSO溶液为原料，研究了偏钛酸的水解动力学和结构演变。通过TiO含量、XRD分析、粒度分布、FT-IR光谱、拉曼分析和HRTEM对样品进行了表征。水解产率曲线呈S型，水解过程包括诱导期、快速水解期和成熟期。快速水解期为一级反应，水解温度升高会缩短诱导期和水解期，而延长成熟期对水解产率和水解速率具有近似线性正相关。灰化点处的实际水解产率与计算得到的水解产率一致。计算得到的指前因子为1.40×10 min，活化能为147.6 kJ/mol。随着水解温度升高，晶粒尺寸增大，晶格应力减小，偏钛酸平均粒径减小，硫含量降低，这是晶体和胶体颗粒生长与调整的结果。此外，SO离子促进了锐钛矿TiO晶体的形成。沉淀颗粒的形成经历了凝胶、晶体生长、聚集和凝聚等过程。
