Sustainable surgical masks: optimizing fine/ultrafine particle filtration using PVA/chitosan electrospun nanofibers

• Published in: Environmental science. Nano 2023-08, Vol.1 (8), p.2185-22
• Main Authors: da Mata, Gustavo Cardoso, Morais, Maria Sirlene, de Oliveira, Wanderley Pereira, Aguiar, Mônica Lopes
• Format: Article
• Language: English
• Subjects: Air pollution; Alcohols; Biodegradation; Chitosan; Electric fields; Electrospinning; Filtration; Flow rates; International regulations; Masks; Membranes; Nanofibers; Optimization; Outdoor air quality; Pandemics; Parameters; Particulate matter; Permeability; Polymers; Polyvinyl alcohol; Pressure drop; Response surface methodology; Severe acute respiratory syndrome coronavirus 2; Substitutes; Suspended particulate matter; Ultrafines; Viral diseases; Viruses
• ISSN: 2051-8153; 2051-8161
• DOI: 10.1039/d3en00182b

Disposable surgical masks have emerged as a solution to the increasing demand for protection against fine/ultrafine particulate matter. This was prompted by the SARS-CoV-2 pandemic and the escalating levels of air pollution in major cities. However, as non-degradable polymers, surgical masks are discarded into the environment and become pollutants. This study produced biodegradable nanofibers via electrospinning, using polyvinyl alcohol (PVA) and chitosan (CS) as substitutes for traditional polymers in a three-layer commercial surgical mask (CSM). Electrospinning production parameters were modeled using response surface methodology and optimized using the desirability method. Then, the air filtration properties, including quality factor ( Q f ), collection efficiency ( η ), pressure drop (Δ P ) and permeability ( K 1 ), were compared with CSM. The main objective was to produce electrospun mats with filtration of fine/ultrafine particles similar to those obtained for the CSM ( η : 42.84-67.80% and Δ P : 29.3-32.2 Pa). Subtle variations in production parameters significantly affected the material, with the electric field being the most relevant parameter. The optimized samples OEV(↓ K 1 ) and OEV(↓ Q f ) presented the highest η values (96.27 and 96.58%, respectively), matching the N95 filtration efficiency and complying with international regulations. Their optimal experimental sets were, respectively, 25.01 and 23.39 kV of tension applied for the electrical field, 0.92 and 1.17 mL h −1 of flow rate, and 24.87 and 27.93 min of production time. Notably, nanofibers were more effective than the CSM in capturing particles close to the nanoscale range, such as airborne viruses and fine/ultrafine air pollution. The PVA/CS electrospun membranes are becoming promising alternatives to substitute non-degradable polymers in surgical masks. PVA/chitosan electrospun nanofibers optimized with response surface methodology were used as substitutes for nondegradable polymeric filtering layer of surgical masks. Testing proved the nanofibers' efficacy for air filtration of ultrafine particles.