ways to recycle protective masks

Several weeks now that the coronavirus, responsible for Covid-19 pandemic, circulates in populations. A crisis that has brought the issue of protective masks. And, in most countries of the world, that of a risk of shortage of this equipment. Why ? Because Chinese production capacities were, for a time, greatly reduced. But mainly because after only a few hours of use, they lose their effectiveness and must be replaced. For single use, a colossal quantity of these masks is therefore necessary in these times of pandemic.

As the authorities seek to relaunch production, scientists are working on other solutions. Of recycling solutions which, after use, would eliminate the viral load of these masks while maintaining their level of performance. Thus, in full containment, the CNRS and the CEA have set up an interdisciplinary consortium which is exploring several possibilities.

Virucidal and bactericidal treatments

In an interview at CNRS Journal, Philippe Cinquin, professor of public health and hospital practitioner, explains the long evaluation work implemented for each track. That ofirradiation by gamma rays – that is to say using photons very high energy –, for example. Collection of used masks, irradiation tests, work on the consequences of irradiation on the material constituting masks and performance Review after treatment and disinfection efficiency on bacteria present in the masks.

Other possibilities are explored along the same lines: sterilization beta – using bundles ofelectrons -, oxide treatmentethylene (VS₂H₄O), the transition to autoclave at 121 ° C for 50 minutes, washing in detergent at 60 or 95 ° C or heating at 70 ° C in heat dry or in water. These latter washing methods also aim to remove organic residues which could protect the pathogens and reduce the effectiveness of others protocols decontamination.

Variable results

The first results reported by the consortium report variable effectiveness depending on the type of mask. Thus gamma irradiation works well on surgical masks. However, it does not make it possible to maintain the performance of the FFP2 masks. Dry heat at 70 ° C, however, would very effectively destroy the viral load on these two types of masks.

In other countries too, researchers are exploring ways to recycle protective masks. For example, the Dutch National Institute for Public Health and the Environment has published a study who concludes that the FFP2 masks can be reused three times, provided they are decontaminated using hydrogen peroxide (H₂O₂) between each of these uses.

An information platform

In the United States, researchers have just launched a platform, N95decon.org – with reference to N95 masks which are the equivalent of our FFP2 masks – intended to synthesize the scientific literature available on this subject. And they offer a decryption for mask users and decision makers. Thus, they advise, for those who would like to use ultraviolet devices ((UV), to ensure that the entire surface of the masks is treated with sufficient energy. And like their colleagues in the Netherlands, they imagine that a method based on steam from hydrogen peroxide could be implemented on a large scale.

A note also detailing some mistakes not to make was also posted online, no later than this Sunday. It indicates for example that the use ofalcohols ethanol type must be prohibited. This degrades the properties of filtration N95 masks. Ditto for washing with bleach, the residues of which could also have undesirable effects on the health of those who wear masks thus cleaned.