Kinetics study to identify reaction-controlled conditions for supercritical hydrothermal nanoparticle synthesis with flow-type reactors
Kinetics study to identify reaction-controlled conditions for supercritical hydrothermal nanoparticle synthesis with flow-type reactors
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DOI：
10.1016/j.supflu.2015.11.015
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发表时间：
2016-04-01
影响因子：
3.9
通讯作者：
Adschiri, Tadafumi
中科院分区：
文献类型：
--
作者：
Aoki, Nobuaki;Sato, Ayato;Adschiri, Tadafumi
流动式反应器是精确控制反应条件和高通量生产的有效装置。为了提高这一过程的有效性，需要建立一种设计方法。为此，在流动式反应器中考察了操作参数对超临界水热纳米颗粒合成的影响。以2.0 mm的硝酸铈为原料，在200-380℃的反应温度下，以11.6-37.5毫升/分钟的流速制备了纳米氧化铈。此外，使用0.3、1.3和2.3 mm的通道尺寸作为混合点。研究发现，快速混合和较高的温度可以形成更小的纳米颗粒。此外，所有的实验结果都用无量纲数进行了总结。虽然雷诺数与混合对颗粒形成的影响有关，但雷诺数与反应速率无关。使用Damkohler数、反应速率与混合速率的比率对结果进行关联。根据Damkohler数的阈值，可以预测颗粒尺寸与流动/混合速率无关的反应控制条件。(C)2015爱思唯尔B.V.保留所有权利。
Flow-type reactors are effective for the precise control of reaction conditions and high throughput production. To enhance the effectiveness of this process, the establishment of a design method is required. For this purpose, the effects of operating parameters on supercritical hydrothermal nanoparticle synthesis in a flow-type reactor were examined. Ceria nanoparticles were formed from 2.0 mM cerium nitrate at reaction temperatures ranging from 200 to 380 degrees C and with a flow rate of 11.6-37.5 mL/min. In addition, channel sizes of 0.3, 1.3, and 2.3 mm were used for the mixing point. Rapid mixing and higher temperatures were found to enable the formation of smaller nanoparticles. Furthermore, all experimental results were summarized using dimensionless numbers. Though the Reynolds number was related to the effect of mixing on particle formation, this number is independent of the reaction rate. Results were correlated using the Damkohler number, the ratio of reaction rate to mixing rate. From the threshold value of the Damkohler number, reaction-controlled conditions where the particle size was independent of the flow/mixing rate could be predicted. (C) 2015 Elsevier B.V. All rights reserved.