Table 4.
Known strategies to improve municipal waste management and develop biodegradable masks.
| Overall solution | Specific strategy/materials | Strategy description | Reference |
|---|---|---|---|
| Improving municipal waste management | Specific waste collection bins | Specific waste bins for disposable masks in public places, with daily collection. | Benson et al., 2021 |
| Proper treatment of discarded masks | Separate collection, transportation, storage, and disposal of non-infected and infected masks. | Facebook, 2020; WHO, 2020; Silva et al., 2021a, Silva et al., 2021b | |
| Reprocessing and reuse of discarded masks | Decontamination using autoclaving, UV irradiation, chemical treatment, hydrogen peroxide vapor, dry heat pasteurization, or dry and moist heat treatments can retain the filtering capacity and successfully reduce the infectivity of masks. | Gertsman et al., 2020; Schumm et al., 2021 | |
| Innovating mask waste disposal methods | Construction material | Waste mask fibers can be used as additives in diverse construction materials to enhance their tensile/bending strengths and crack resistance. | Ahmed and Lim, 2022; Saberian et al., 2021 |
| Membrane material | The nanofiltration membranes prepared from waste masks by green solvents (e.g., p-cymene) as extractants had superior chemical stability and were suitable for organic solvent nanofiltration. | Cavalcante et al., 2022 | |
| Fuel | Waste masks can be transformed into fuels through pyrolysis, possessing high calorific value, including gasoline, jet fuel, diesel, motor oil, bio-char, and non-condensable gases. | Aragaw and Mekonnen, 2021; Park et al., 2021 | |
| Battery electrode | The functionalized porous carbons prepared from waste masks by microwave-assisted solvothermal method had good electrochemical performance. | Hu and Lin, 2021; Chao et al., 2022 | |
| Adsorbent | The activated carbon adsorbents prepared from waste masks by sulfonation chemistry and thermal stabilization technology can be used for oil adsorption and removing organic pollutants from aqueous. | Chao et al., 2022; Robertson et al., 2022 | |
| Gas sensors | The waste mask fibers/ZnS sensor prepared from waste masks and ZnS nanoparticles by one-step hydrothermal method had high sensitivity to target vapors. | Wang et al., 2022b | |
| Catalytic supports | Waste mask fabrics can be used as a free-standing catalytic support for the deposition of titanium dioxide (TiO2), iron oxide (FexOy), and cobalt oxide (CoOx) metal oxide nanoparticles. | Muhyuddin et al., 2022; Reguera et al., 2022 | |
| Useful chemical products | Waste masks can be successfully converted into useful chemical products through a combination of tandem catalysis and biodegradation (e.g., enzymes present in the saliva of wax worms). | Sullivan et al., 2021; Sanluis-Verdes et al., 2022 | |
| Developing biodegradable masks | Gluten nanofiber | Wheat gluten biopolymers, a by- or co-product of cereal industries, can be transformed into electrospun nanofiber membranes and compressed molded gluten for the development of biodegradable face masks. | Das et al., 2020 |
| Poly lactic acid (PLA) | Electrospinning and 3D printing have been used to strut PLA polymer on a PLA nanofiber web to fabricate face masks. | Patil et al., 2021; Soo et al., 2022 | |
| Banana stem fiber | Masks produced by banana stem fibers extracted from banana peel can be recycled and biodegraded easily. | Sen et al., 2021 | |
| Chitosan nanowhiskers | Two biodegradable microfiber and nanofiber mats can be integrated into a mask and coated by cationically charged chitosan nanowhiskers. The mask can completely decompose within four weeks in composting soil. | Choi et al., 2021 | |
| Polyhydroxyalkanoates (PHAs) | PHA face masks are characterized by the solidity and porosity of the polymer, non-stick features, and biodegradability. | Al-Hazeem, 2021 |