Science & Technology

Rice University Creates Effective Recipes for Decontaminating Disposable COVID Face Masks at Home

Rice University graduate students Faye Yap (left) and Zhen Liu show the characteristics of the mask sample. Researchers at Rice and Galveston School of Medicine at the University of Texas have established a framework for proper decontamination of disposable face masks. They determined that heating the mask in an oven at 160 degrees Fahrenheit for 5 minutes would kill more than 99.9% of the tested viruses, including SARS-CoV-2. Credit: Jeff Fitlow / Rice University

If you heat the PPE to a reasonable degree, 99.9% will die. SARS-CoV-2 Virus without degrading the material.

The recipe for decontaminating disposable face masks is: Heat to 160 degrees. Fahrenheit 5 minutes in the oven. You can use your own oven.

According to rice university engineers, science now confirms through extensive experimentation and modeling that it has determined to eliminate viruses caused by proper heating. COVID-19 (new coronavirus infection) From a standard disposable surgical mask without degrading the mask itself.

George R from Rice University. A study by Daniel Preston, a mechanical engineer at the Brown School of Engineering, Faye Yap, a graduate student at Rice University, and Galveston, a collaborator at the University of Texas School of Medicine (UTMB), can be decontaminated and reused multiple times before disassembling the mask. Is shown.

Above all, heat to 70 degrees Celsius (Approximately 160 F) killed more than 99.9% of SARS-CoV-2 and other viruses they tested and met FDA guidelines for decontamination. This shows the potential for personal protective equipment (PPE) to adapt the protocol to address valuable future outbreaks.

Details of the study Journal of Hazardous Materials..

Fayeap and Jenriu

Rice University graduate students Faye Yap (left) and Zhen Liu show the characteristics of the mask sample. Researchers at Rice and Galveston School of Medicine at the University of Texas have established a framework for proper decontamination of disposable face masks. They determined that heating the mask in an oven at 160 degrees Fahrenheit for 5 minutes would kill more than 99.9% of the tested viruses, including SARS-CoV-2. Credit: Jeff Fitlow / Rice University

This paper is the third in a series triggered by the COVID-19 pandemic and supported by the National Science Foundation’s Rapid Response Research grant. NS First paper In August 2020, it was suggested that a thermal approach to decontamination is feasible. NS Second paperIntroduced in May of this year, compared the effects of ambient temperature range on viruses in several parts of the United States.

Current research presents a modeling framework that researchers can use to determine how much heat and how long it takes to kill a particular virus. Preston pointed out that the framework applies not only to airborne viruses such as SARS-CoV-2, but also to viruses that live on the surface and are mainly transmitted by contact.

In explaining their strategy, study authors Yap and Preston elaborated on decontamination methods that were attempted but only worked to some extent. Steam as it can damage the structure of the mask. Or a chemical disinfectant that can leave harmful residues and degrade the material.

“In general, UV light has been shown to be very effective, especially for flat or smooth surfaces,” said Preston, an assistant professor of mechanical engineering. “There’s a lot of good work out there, but not everyone has access to UVs, and heat overcomes the problems posed by gaps and creases in the fabric.”

Preston, along with Gallveston’s collaborators who performed most of the heating experiments, found that little work was done to create a modeling framework for decontaminating PPE in his laboratory. Judging that it was suitable for the job.

“We couldn’t really find any literature that clearly explained the effect of temperature on decontamination of the virus,” he recalled. “At least nothing is applicable to a pandemic. It involved us in this even before we applied for a grant.

Surgical mask containing active virus

Researchers at Rice University and the University of Texas at Galveston have determined the best way to inject a standard surgical mask with droplets containing the active virus and decontaminate the mask with dry heat. Credit: Jeff Fitlow / Rice University

“Ultimately, what we hypothesized and now found to be true is that thermal inactivation of the virus can be easily explained by a combination of the two basic relationships,” he said. Said. “One of them Arrhenius equation, Associate reaction parameters with temperature.And the other is Rate method, These reaction parameters are used to indicate the rate at which the reaction occurs. In this case, the reaction is the inactivation of the virus itself. “

It’s important to keep the mask completely hot, Yap said. The mask is thin, so it’s not as problematic as decontaminating large objects. This is a topic for future research by the Preston Institute. Heating to 70 ° C should work with cloth masks as long as all layers reach the required temperature for 5 minutes.

She said that if the heat was too high, the polymer fibers that make up most of the masks would melt, as seen in the microscopic images of the sample. “At about 125 ° C, the mask’s (center) filter layer begins to deform and melts at 160 ° C,” says Yap. “As you start approaching the melting point of the material, there are thin lines.”

But if the decontamination protocol works, it works very well. “If we can heat the whole mass to the proper temperature of 70 ° C, we can inactivate the virus within 5 minutes,” says Yap. She said that heating the mask to the proper temperature for up to 30 minutes did not significantly degrade the mask.

Hoping that COVID-19 is declining in the West, Preston said the shortage of PPE remains a problem in many parts of the world. An easy and effective way to decontaminate a mask can help many. However, the ability to reuse masks is not everything to keep you safe during a pandemic.

“I don’t want to say that heat-induced inactivation of surface-stabilized viruses is the main factor in preventing the spread of COVID-19,” he said. “The virus continues to spread through aerosolized droplets that are transmitted from one person to another. Masks can prevent it, and decontamination is a secondary prevention to limit its spread. It represents a plan. “

Reference: “Effectiveness and Self-Similarity of SARS-CoV-2 Thermal Decontamination”, Te Faye Yap, Jason C. Hsu, Zhen Liu, Kempaiah Rayavara, Vivian Tat, Chien-Te, K. Tseng, Daniel J. Preston, 7 November 2021 Journal of Hazardous Materials..
DOI: 10.1016 / j.jhazmat.2021.127709

Jason Hsu of UTMB is the co-author of this paper. Co-authors are Zhen Liu, a UTMB rice graduate student, Kempaiah Rayavara, a research scientist, Vivian Tat, a graduate student, and Chien-Te Tseng, a professor of microbiology and immunology.

National Science Foundation grants 2030023 and 2030117 supported the research.



Rice University Creates Effective Recipes for Decontaminating Disposable COVID Face Masks at Home

https://scitechdaily.com/rice-university-creates-effective-recipe-to-decontaminate-disposable-covid-facemasks-at-home/ Rice University Creates Effective Recipes for Decontaminating Disposable COVID Face Masks at Home

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