Durable and efficient membrane filter for building air purification of virus and smog particulates

With the world severely affected with airborne pandemic and increasing frequency of climate change fueled wildfires, there is a dire need for low-cost air treatment solutions to mitigate the risk and improve overall health and wellbeing. Conventional HEPA air filters are limited by their cost due to the need for regular replacement of the one-time use filters. This problem is exacerbated as air quality deteriorates further. A low-cost, durable, reusable air filter unit, with similar performance attributes as current HEPA filters that can be easily regenerated would be of great service to public health. Durable, compact, high-efficiency air filter units are proposed that utilize thin (50 µm) microporous metal sheets These robust metal membrane sheets with networked porous structures through its thickness allow for low pressure drops during operation. Most importantly, the smooth membrane surface filters out particulates such as harmful viruses and carcinogens via the size exclusion principle, without being fouled internally, as in the case of conventional HEPA filters. This allows for simple and quick sterilization and cleaning processes to be developed to regularly restore the filter performance without the cost and waste associated with current HEPA filter units. Further, biocidal nano-silver and copper coatings on the membrane will prevent any bacterial proliferation within these filters. In Phase I, an 8” x 8” x 6” prototype unit with 130 scfm air flow will be built to demonstrate the clear advantages of the proposed technology over currently used HEPA units of similar capacity. An effective cleaning method will be developed to regenerate the membrane periodically to restore performance to original levels. Manufacturing developments will be made to achieve an eventual cost target of $25/m2 by tailoring the membrane sheet towards the air filtration application. Bench-top filtration tests will be used to corelate membrane properties with filter performance with particulates, especially nano carbons and simulated viruses. Ultimately, these tests will inform the final design of the prototype unit. Overall improvement to air quality will lead to improved health outcomes across the US by dramatically lowering the cost of owning air purifiers particularly in households, schools, commercial buildings. The economic and human toll caused by the current coronavirus pandemic due to airborne transmission has been huge. Such rapid airborne disease proliferation may be mitigated in the future with widespread deployment of high-quality air purifiers as proposed here. New jobs will be locally created in the US for manufacture and service of these novel membrane air filters.