Enhancement of Gas-liquid Mass Transfer using Magnetite Nanoparticles

美国国家科学基金会化学和生物分离项目授予的这一奖项支持了堪萨斯州立大学亚历山大·p·马修斯教授的研究工作，该研究旨在研究利用纳米颗粒和纳米壳作为载体提高气液传质和反应速率的方法和机制。纳米颗粒和介孔纳米壳具有高表面积和高迁移率等独特性质，可用于改变气液传质过程中的气泡特性。纳米粒子的尺寸在流体动力边界层的范围内，可以用来在边界层上传递质量。此外，吸附剂纳米颗粒可以从液相吸收溶质，并迅速将溶质转移到气相。由于(1)液-气传质之外的平行液-固-气传递机制，(2)气泡停留时间的增加，以及(3)空化气泡和超声场下的空化，该过程预计将提供数倍的传质速率增加。本研究将考察在存在和不存在超声场的情况下，惰性和吸附性纳米颗粒影响溶解有机污染物从水到气相的传质速率的机制。气液传质过程在自然和工程系统中都很重要。从这项工作中获得的知识的应用将提供更有效的手段，用于在饮用水净化、加工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方面进行传质作业。

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.