Manufacturing of Silicon Ceramic Membranes via One-Pot Deposition and Pyrolysis of Preceramic Polymers for Water Treatment and Hydrogen Separation.

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This grant supports research toward the development of membranes for energy applications. Increasing access to energy sources is very important for advancing the U.S. economy. As the demand for energy continues to increase, hydrogen has been increasingly considered as a viable alternative energy source for engines, turbines and fuel cells. To make this a realistic option, hydrogen must be efficiently separated from other gases and, therefore, it is crucial to manufacture robust inorganic ceramic membranes that can operate at high temperatures and pressures. Current methods to fabricate these membranes are costly, time-consuming and produce toxic waste. This award supports fundamental research that leads to the development of a solvent-free, one-pot or single step manufacturing process to fabricate inorganic membranes for hydrogen separation. This new manufacturing process leads to a more cost-effective and environmentally-friendly way to provide clean energy sources, which leads to national prosperity and security. This award supports the education of future scientists and engineers through outreach to K-12 students and mentorship of undergraduate researchers. This manufacturing technology can also lead to the development of membranes for other applications such as water purification. Hands-on modules demonstrating the use of membranes for water purification are developed to educate middle and high school students on the lack of access to clean water in many parts of the world.Traditional processes for making inorganic membranes require multiple steps and organic solvents, leading to higher cost and toxic waste. This research gains scientific insights that allow for the development of solventless, one-pot manufacturing of inorganic membranes. Pre-ceramic polymers are deposited in a reactor using a solvent-free process that requires very low energy and mild reactor conditions and employs a broad range of monomers to generate a variety of polymer films. Deposition of a dense, thin polymer layer on top of a macroporous silicon carbide support is ideal for creating high-quality nanoporous ceramic membranes for efficient hydrogen separation. A low vapor pressure liquid barrier layer, which itself serves as a ceramic precursor, is placed on the support before polymer deposition in order to prevent infiltration of the monomer into the support and thus avoid negatively impacting the permeation characteristics of the resulting membrane. Pyrolysis of these films is conducted in the same reactor, hence one-pot, to produce reliable ceramic membranes with lower risk of contamination. The research generates understanding of mechanistic insights on bond cleavage and formation during pyrolysis. Experimental efforts are coupled to multi-scale modeling studies to understand the fundamental reaction and transport processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.