Insight into the microplastics release from disposable face mask: Simulated environment and removal strategy

The fight against the COVID-19 epidemic significantly raises the global demand for personal protective equipment, especially disposable face masks (DFMs). The discarded DFMs may become a potential source of microplastics (MPs), which has attracted much attention. In this work, we identified the detailed source of MPs released from DFMs with laser direct infrared spectroscopy. Polypropylene (PP) and polyurethane (PU) accounted for 24.5% and 57.1% of released MPs, respectively. The melt-blown fabric was a dominant MPs source, however, previous studies underestimated the contribution of mask rope. The captured polyethylene terephthalate (PET), polyamide (PA), polyethylene (PE), and polystyrene (PS) in airborne only shared 18.4% of released MPs. To deepen the understanding of MPs release from medical mask into the aquatic environment, we investigated the effects of environmental factors on MPs release. Based on regression analysis, the effects of temperature, incubation time, and wearing time significantly affect the release of MPs. Besides, acidity, alkalinity, sodium chloride, and humic acid also contributed to the MPs release through corroding, swelling, or repulsion of fibers. Based on the exposure of medical mask to simulated environments, the number of released MPs followed the order: seawater > simulated gut-fluid > freshwater > pure water. Considering the risk of MPs released from DFMs to the environment, we innovatively established a novel flotation removal system combined with cocoamidopropyl betaine, achieving 86% removal efficiency of MPs in water. This work shed the light on the MPs release from DFMs and proposed a removal strategy for the control of MPs pollution.

Automated summary

The global demand for personal protective equipment, especially disposable face masks, has greatly increased due to the COVID-19 epidemic. Disposable face masks may become a potential source of microplastics, which has gained significant attention. In this study, the detailed sources of microplastics released from disposable face masks were identified using laser direct infrared spectroscopy. Polypropylene and polyurethane were found to be the major contributors to released microplastics. The melt-blown fabric was the dominant source, while previous studies underestimated the contribution of the mask rope. The study also investigated the effects of environmental factors on microplastics release, finding that temperature, incubation time, wearing time, as well as acidity, alkalinity, sodium chloride, and humic acid were all significant factors. The study further proposed a novel flotation removal system combined with cocoamidopropyl betaine to efficiently remove microplastics from water, providing insights into microplastics release from disposable face masks and a potential strategy for controlling microplastic pollution.