NER: Fractal Nanoagglomerates: A New Filter Media For HEPA Filters

该项目旨在确定一种由纳米颗粒分形凝聚体构成的介质是否能作为一种高效、经济的过滤器，从气流中去除超细气溶胶颗粒，并评估这种过滤介质在提供低压降、高过滤效率和堵塞前的高容量方面，是否能比基于纤维的HEPA过滤器表现得更好。这项工作还将开发模型来预测过滤效率、压降和纳米团聚体过滤介质的容量。在干燥状态下，纳米颗粒由具有分层分形结构和高孔隙率（0.99）的多孔团块组成。这种结构导致团聚体内部的多模态孔径分布，这与广泛使用的纤维基HEPA过滤器的单模态孔径分布有很大不同。初步证据表明，这种纳米团块过滤器作为深度过滤器，因此具有明显更大的容量（高达两个数量级）比传统的纤维基HEPA过滤器。HEPA过滤器广泛应用于许多工业过程，甚至在家庭中，如果成功，这项工作将具有显着的经济效益。

This project seeks to determine whether a medium made of fractal agglomerates of nanoparticles will act as an efficient and cost-effective filter for removing ultra-fine aerosol particles from gas streams and to evaluate whether such a filter medium can perform as well or better than fiber-based HEPA filters with respect to providing low pressure drop, high filtration efficiency, and high capacity before clogging. The work also will develop models to predict filtration efficiency, pressure drop, and capacity of the nano-agglomerate filter medium. Nanoparticles in the dry state have been found to consist of porous agglomerates with a hierarchical fractal structure and a high porosity ( 0.99). This structure results in a multi-modal pore size distribution within the agglomerates, which is very different from the unimodal pore-size distribution found in widely used fiber-based HEPA filters. Preliminary evidence has shown that such nano-agglomerate filters act as a depth filters and thus have significantly greater capacity (up to two orders of magnitude) than traditional fiber-based HEPA filters. HEPA filters are widely used in many industrial processes and even in homes, and if successful, this work could have significant economic benefits.