Single-use surgical face masks, as a potential source of microplastics: Do they act as pollutant carriers?

Abstract

Millions of people are using face coverings (including single-use surgical face masks) as a result of the COVID-19 pandemic and a large number of used masks, particularly single-use masks enter uncontrolled the environment since most of the users have little information on how to dispose of them safely. This new important waste is a potential source of microplastics, which is found nowadays in many parks, streets, and coastlines. Discarded masks will be finally drained to the ocean polluting the marine environment and threatening marine life. This short communication examines the role of face masks and subsequently mask-derived microplastics as pollutant carriers in environmental compartments (e.g. hydrosphere, biosphere, etc.) by investigating their sorption characteristics regarding dye molecules. In this context, batch-type equilibrium experiments were performed and the effect of different sorption parameters has been explored (i.e. contact time and temperature). The results show that single-use surgical face masks can act as dye carriers (Methylene Blue, Crystal Violet and Malachite Green) in the aquatic environment. In addition, preliminary experiments on the thermal treatment of face masks and the use of the resulting carbonaceous material as efficient adsorbent have been performed, pointing out a possibility for used mask disinfection and recycling.

Keywords: COVID-19; Dyes; Microplastics; Pollutant carriers; Single-use surgical face masks; Sorption.

Graphical abstract

Fig. 1

Sorption isotherms of a) MB, b) CV and c) MG on single-use surgical face masks at different temperatures (293 and 323 K) and varying initial concentration of dyes in solution (5–20 mg/L). Experimental conditions: contact time 24 h, pH 5.5 (for MG dye) or 6.0 (for MB and CV dyes), adsorbent/solution ratio 2.6 g/0.05 L, and agitation rate 125 rpm.

Fig. 2

Effect of contact time (4 – 80 min for MB, 4–1440 min for CV, 1–1620 min for MG) on the sorption capacity of dyes (MB, CV and MG) by single-use surgical face masks. Experimental conditions: pH 5.5 (for MG dye) or 6.0 (for MB and CV dyes), initial dye concentration 10 mg/L, adsorbent/solution ratio 2.6 g/ 0.05 L, agitation rate 125 rpm, temperature 293 K.

Fig. 3

Sorption capacity of dyes (MB, CV and MG) on the carbonaceous material obtained from single-use surgical face masks. Experimental conditions: pH 8.0 (for MG dye) or 9.0 (for MB and CV dyes), initial dye concentration 8 mg/L, adsorbent/solution ratio 0.01 g/ 0.05 L, agitation rate 125 rpm, temperature 293 K.