Hu Guangyan, Zhang Ruoxi, Tang Xiaomei, Sun Pengyue, Wang Taiyu
College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China.
Center for Cryptologic Research, National University of Defense Technology, Changsha 410073, China.
Phys Chem Chem Phys. 2025 Jun 18;27(24):13071-13082. doi: 10.1039/d5cp01246e.
This study investigated in depth the mass transfer behavior of a single CO bubble in sodium silicate solution. The dynamics of the bubble were accurately tracked using high-speed camera technology, and key parameters such as velocity, drag coefficient and mass transfer coefficient during the bubble rising process were analyzed in detail with the data processing ability of MATLAB. The results showed that the concentration of sodium silicate solution had a significant impact on the dissolution behavior of the CO bubble. With the increase of concentration, the initial dissolution rate of the bubble was significantly accelerated, and the bubble in sodium silicate solution disappeared more quickly than that in deionized water. Meanwhile, an increase in liquid level would lead to a decrease of CO dissolution rate. In the study on the influence of solution pH value on CO absorption, it was found that the absorption rate at pH = 11.0 was significantly higher than that at pH = 10.5, and the whole absorption process conformed to the rapid pseudo-first-order reaction model. The kinetic parameters calculated by the model fully revealed the profound influence of solution pH value on the mass transfer and chemical reaction mechanism. Further research on the relationship between CO absorption rate and static pressure indicated that the increase of static pressure could effectively promote CO absorption in the initial stage of the reaction, and there was a significant linear positive correlation between them. However, with the progress of the reaction, due to the coupling effect of various complex factors, the deviation from linearity became pronounced with time. The absorption process could be clearly divided into the initial stage dominated by surface adsorption and preliminary reaction, the intermediate stage with accelerated absorption rate, and the later stage where the absorption rate tended to be stable. Furthermore, by comparing the liquid film mass transfer coefficients in the chemical absorption and physical absorption processes and combining with the relevant theoretical model calculations, the enhancement factor was evaluated. It reflects the enhancing effect of the chemical reaction on the mass transfer process. The empirical correlation established in this study took into account the influence of bubble size and sodium silicate concentration. The research results of this study provide a solid theoretical foundation and important data support for the process optimization of carbonization preparation of white carbon black, and have important reference value for the research and practice in related fields.
本研究深入探究了单个CO气泡在硅酸钠溶液中的传质行为。利用高速摄像技术精确跟踪气泡的动力学过程，并借助MATLAB的数据处理能力详细分析了气泡上升过程中的速度、阻力系数和传质系数等关键参数。结果表明，硅酸钠溶液的浓度对CO气泡的溶解行为有显著影响。随着浓度的增加，气泡的初始溶解速率显著加快，且硅酸钠溶液中的气泡比去离子水中的气泡消失得更快。同时，液位升高会导致CO溶解速率降低。在研究溶液pH值对CO吸收的影响时发现，pH = 11.0时的吸收速率显著高于pH = 10.5时的吸收速率，且整个吸收过程符合快速拟一级反应模型。该模型计算得到的动力学参数充分揭示了溶液pH值对传质和化学反应机理的深远影响。对CO吸收速率与静压关系的进一步研究表明，静压的增加在反应初期能有效促进CO的吸收，且二者之间存在显著的线性正相关。然而，随着反应的进行，由于各种复杂因素的耦合作用，随时间推移偏离线性关系变得明显。吸收过程可清晰地分为以表面吸附和初步反应为主的初始阶段、吸收速率加快的中间阶段以及吸收速率趋于稳定的后期阶段。此外，通过比较化学吸收和物理吸收过程中的液膜传质系数，并结合相关理论模型计算，评估了增强因子。它反映了化学反应对传质过程的增强作用。本研究建立的经验关联式考虑了气泡尺寸和硅酸钠浓度的影响。本研究的成果为白炭黑碳化制备过程的优化提供了坚实的理论基础和重要的数据支持，对相关领域的研究与实践具有重要的参考价值。
