New surgical masks made from plastic bottles and bags
A team of researchers from the Aragon Health Research Institute (IIS Aragon), the Institute of Nanoscience and Materials of Aragon (INMA), a joint institute between the Spanish National Research Council (CSIC) and the University of Zaragoza (Unizar) and the Institute of Carbochemistry of the CSIC, have obtained a new material to replace the polypropylene used to make surgical masks, the most widely used, which is in line with the principles of the circular economy. The project has succeeded in developing filter media based on microfibres and electrospun nanofibres of polyethylene terephthalate (PET) obtained from plastic bottles, bags and other discarded plastic products, which in turn can be recycled to make new masks, thereby reducing the environmental impact caused by the mandatory wearing of masks due to the COVID-19 pandemic.
By combining different sizes of microfibre or nanofibre it is possible to generate filter media with a wide spectrum of filtering efficiencies (surgical, FFP1, FFP2 and FFP3). Compared to the polypropylene commonly used in face masks, this material is also hydrophobic, can be recycled and re-spun, and is made from discarded plastic, so it is considered more sustainable and environmentally friendly.
The developed mask consists of three layers: two outer layers, located on the inner and outer sides, and a filter medium as a middle layer. The two protective layers show hardly any loss of charge, but high hydrophobicity. Both fabrics are produced by electrospinning techniques. The fabric has a retention efficiency of over 98% for particles of between 0.5 and 3 microns and 100% for particles of 3 microns and above. Thus, compared to the current surgical mask, the PET-based fabric performs better in the retention of fine and coarse particles.
These materials have been obtained in the facilities and with the resources of the IIS Aragón, the Institute of Nanoscience and Materials of Aragon (CSIC-University of Zaragoza) and the Institute of Carbochemistry of the CSIC (former Laboratory of Fluid Dynamics and Combustion Technologies).
Impact on the environment
Although there is a wide range of masks with varying efficiency, from surgical and hygienic masks to filtering half masks, most commercial filtering media are based on polypropylene. Most mask models, regardless of their filtering capacity, are categorised as non-reusable and the product’s shelf life expires after 4 to 6 hours of continuous use, depending on the manufacturer. Bearing in mind that, according to 2020 data from the National Institute of Statistics, the Spanish population aged 6 years or over amounts to 46,440,788 inhabitants, if all of them used two surgical masks a day -complying with the recommendations-, this would generate 232 tonnes of polypropylene waste per day (2.5 grams per mask).
The team that has achieved this innovation consists of Marta Baselga, principal investigator (IIS Aragón); Santiago Jiménez (LIFTEC); and Manuel Arruebo, Cristina Yus, Víctor Sebastián and Silvia Irusta (INMA). The project has been funded by the IIS Aragón in the framework of the intramural call for proposals ‘Acción de apoyo del IIS Aragón Covid-19’ of 2020 and by the University of Zaragoza, within the framework of the call for proposals for development cooperation projects and initiatives in the university field 2020.
16/06/2021
