Enhancement of Gas-liquid Mass Transfer using Magnetite Nanoparticles

CBET-0827894 Mathew这项由化学和生物分离计划颁发的NSF奖项支持堪萨斯州立大学Alexander P.Mathews教授的工作，他研究了使用纳米颗粒和纳米壳层作为航天器来增强气液传质和反应速率的方法和机理。纳米颗粒和介孔纳米壳层具有高比表面积和高迁移率等独特性质，可以用来改变气液传质中的气泡性质。纳米颗粒的尺寸在流体动力学边界层的范围内，可以用来通过边界层传输质量。此外，吸附纳米颗粒可以从液相中吸附溶质，并将溶质快速穿梭到气相中。由于(1)除了液-气传质之外，还有一种平行的液-固-气传递机制，(2)增加了气泡停留时间，(3)气泡和超声场下的空化气泡，这一过程有望使传质速率增加数倍。这项研究将考察在有无超声场的情况下，惰性纳米颗粒和吸附纳米颗粒在溶解的有机污染物从水到空气相转移过程中影响传质速率的机制。气液传质过程在天然系统和工程系统中非常重要。从这项工作中获得的知识的应用将为在饮用水净化、过程工业中的多相反应以及从受污染的地下水和废水中去除挥发性有机化合物提供更有效的传质操作手段。

CBET-0827894MathewsThis NSF award by the Chemical and Biological Separations Program supports work by Professor Alexander P. Mathews of Kansas State University to investigate methods and mechanisms to enhance gas-liquid mass transfer and reaction rates using nanoparticles and nanoshells as shuttles. Nanoparticles and mesoporous nanoshells possess unique properties such as high surface area and mobility, and these can be used to advantage in changing bubble properties in gas-liquid mass transfer. Nanoparticle sizes are in the range of hydrodynamic boundary layers, and can be used to transport mass across the boundary layer. Moreover, adsorbent nanoparticles can sorb solutes from the liquid phase and rapidly shuttle the solutes to the gas phase. This process is expected to provide several fold increase in mass transfer rates due to (1) a parallel liquid-solid-gas transfer mechanism in addition to liquid-gas mass transfer, (2) increased bubble residence time, and (3) cavitating bubbles and under ultrasonic fields. This research will examine the mechanisms by which inert and adsorbent nanoparticles will affect mass transfer rates in the transfer of dissolved organic contaminants from water to the air phase in the presence and absence of ultrasonic fields. Gas-liquid mass transfer processes are important in natural and engineered systems. The application of knowledge gained from this work will provide more efficient means of conducting mass transfer operations in drinking water purification, multiphase reactions in the process industries, and in the removal of volatile organic compounds from contaminated groundwaters and wastewaters.