A Novel Idea: New Sorbents to Increase Mask Efficiency and Capabilities

Greg Peterson, left, and Rick Cox discuss metal-organic frameworks (MOFs) in front of the ammonia breakthrough system. The CBR Filtration Branch is currently working on maturing and eventually transitioning MOFs for use as highly effective layers for ammonia (and other TICs) removal in military and industrial filters.

What does nanotechnology – which focuses on matter at the molecular scale – have to do with the bulky masks and filters our warfighters wear for protection against highly toxic compounds?

U.S. Army Edgewood Chemical Biological Center (ECBC) Principal Investigator Greg Peterson, along with Rick Cox, Ph.D., chief of the Chemical, Biological and Radiological (CBR) Filtration Branch, has been leading efforts at ECBC to use state-of-the-art nanotechnology and materials science to improve mask filtration. The goal is to increase filter and mask efficiency, broaden filter capabilities to meet emerging threats and reduce the burden to the warfighter.

ECBC is working to develop novel, advanced sorbents to replace the current activated carbon used in filters. Carbon has been used in the military for nearly a century to purify air; it is effective against highly toxic compounds such as nerve and blister agents, but less so against highly volatile toxic industrial chemicals (TICs). In addition, activated carbon is relatively inert and must be treated with metal impregnants for maximum performance; carbon can accept only so many impregnants before the pores are clogged and the filter becomes ineffective. The nanotechnology effort involves removing the activated carbon and instead synthesizing highly reactive substrates, thus reducing the volume required to remove TICs.

Warfighters have commented that traditional masks are uncomfortable to wear – they retain heat, they fog up, they impede breathing. The new materials will help reduce breathing resistance and filter volume, ultimately advancing both safety and comfort for warfighters.

In addition to offering improved and broader protection against priority chemicals, the new materials “will provide improved physical characteristics, such as being inherently reactive, offering greater stability and capacity, and being non-flammable,” Peterson said.

“It’s a paradigm shift from a filter capturing something to a filter that’s reactive and not just captures but also destroys a toxic compound,” said Cox.

The scientists stated that the new materials allow for developing different configurations, rather than being confined to the traditional round filter canister. “Now we can make filters that conform to the head or are molded in a comfortable design,” said Peterson. “Newer filters are lighter and more streamlined.” In fact, some new materials were recently incorporated into two novel filter designs in the Future CB Ensemble / Ground Soldier System Technology Demonstration, a program in which personnel from ECBC and the U.S. Army Natick Soldier Research, Development and Engineering Center jointly developed novel filter concepts for the future force.

Funded by the Defense Threat Reduction Agency Joint Science and Technology Office for Chemical and Biological Defense, ECBC is working with various partners, such as the U.S. Naval Research Laboratory, Georgia Institute of Technology, and University of California at Los Angeles, to develop the novel materials. These materials include functionalized carbon nanotubes, metal-organic frameworks, polyoxometalates, carbon-silica composites, organosilicates, and microporous polymers.

“Researchers at the head of their fields are developing these new sorbents,” said Peterson. “We provide the research goals and testing; they build the materials. Our goal is to find the material that gives the warfighter the best protection against the most chemicals.”

Peterson described one of ECBC’s sorbent efforts in an article he cowrote with Joseph Rossin of Guild Associates, Inc. The article, “Replacing a Legacy: A Novel Sorbent for Future Systems,” was accepted for publication by the quarterly Chem-Bio Defense Magazine.