(264f) Understanding the Formation Mechanism of Hierarchically Porous Petrified Hollow Fiber Membranes

Inorganic membranes are broadly useful for chemical separation and filtration, which are often formed by coating/growth of a molecularly selective layer on top of macroporous oxide hollow fiber substrates. Macroporous oxide hollow fiber substrates are conventionally made by high-temperature processes such as phase inversion-sintering, in which polymer/oxide (e.g., α-alumina) mixed-matrix hollow fibers are sintered at 1200-1500 °C. These high-temperature fabrication processes are expensive, which limit the large-scale applications of inorganic membranes. Petrified hollow fiber membranes¹ represent a novel class of porous oxide hollow fiber membranes recently developed at the University of Maryland. They are derived from polymer hollow fiber templates by a simple three-step process consisting of: (1) silane soaking, (2) moisture exposure, and (3) air heating. Unlike macroporous oxide hollow fibers formed by phase inversion-sintering, fabrication of petrified hollow fiber membranes occurs at much lower temperatures (600 °C). The lower formation temperature and reduced manufacturing cost make them promising substrates for scalable inorganic membranes. In this talk, we will present the synthesis and characterizations of petrified hollow fiber membranes. Scanning and transmission electron microscopy, thermogravimetric analysis, nitrogen and argon physisorption, mercury intrusion porosimetry, infrared spectroscopy, and water vapor adsorption measurements were carried out, which allowed us to propose a hypothetical formation mechanism of these novel hierarchically porous petrified hollow fiber membranes.

References:

¹Liu, L.; Ku, C.-E.; Zhang, C., Petrified Hollow Fiber Membranes with Hierarchical Pores. ACS Materials Letters 2022, 938-943.