US 12,403,418 B2
Nanoporous metal foam gas and fluid filters
Kai Liu, Falls Church, VA (US)
Assigned to Georgetown University, Washington, DC (US)
Filed by Georgetown University, Washington, DC (US)
Filed on Sep. 25, 2019, as Appl. No. 16/582,123.
Application 16/582,123 is a continuation of application No. PCT/US2018/026343, filed on Apr. 5, 2018.
Claims priority of provisional application 62/482,594, filed on Apr. 6, 2017.
Prior Publication US 2020/0086257 A1, Mar. 19, 2020
Int. Cl. B01D 39/00 (2006.01); B01D 39/20 (2006.01); B01D 46/24 (2006.01); B01D 46/60 (2022.01)
CPC B01D 39/2051 (2013.01) [B01D 46/24 (2013.01); B01D 46/60 (2022.01); B01D 2239/0478 (2013.01); B01D 2239/1216 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A filtration system comprising:
a filter housing defining an interior, wherein the filter housing includes an intake port and an output port;
a first filter element disposed within the interior of the filter housing between the intake port and the output port, wherein:
said first filter element comprises a freeze-cast, polycrystalline metal foam comprising of a three-dimensional interconnected ultrafine metallic wire network having interconnections of interconnected ultrafine metallic wires consisting of a non-metal-oxide metal, and wherein the metal foam is formed from a process that comprises:
a formation step consisting of forming a dispersion of the metallic nanowires in a liquid,
a placement step that consists of placing the dispersion in a form and freezing the dispersion,
a sublimation step consisting of leaving a structure of interlocked nanowires,
a bonding step consisting of bonding points of contact between the nanowires,
the interconnected ultrafine metallic wire network comprises a plurality of nanometer to micron scale pores defined by gaps between the interconnected ultrafine metallic wires,
the interconnected ultrafine metallic wire network is configured to capture at least some of a plurality of neutral particulates in a flow as the flow passes through the first filter element, and
the interconnected ultrafine metallic wires have dimensions in the nanometer to micron scale;
a voltage source electrically coupled to the first filter element that is operable to apply a voltage to the first filter element so that the first filter element functions as an ionization grid capable of charging at least some of the plurality of neutral particulates in the flow as the flow passes through the first filter element, resulting in the plurality of neutral particulates becoming a plurality of charged particulates; and
a second filter element disposed within the interior of the filter housing that is downstream from the first filter element through which the flow passes, wherein:
the flow comprises the plurality of charged particulates, the second filter element comprises a coated metal foam that is capable of trapping at least some of the plurality of charged particulates within the coated metal foam, and
the coated metal foam comprises an interconnected ultrafine metallic wire network coated with a catalytic metal oxide or carbon.