Mask Waste: A Sustainable Mask-Based Epoxy Resin/SiO₂ Composite for Efficient Purification of Water-in-Oil Emulsions

Abstract

Since the emergence of the COVID-19 pandemic, there has been a tremendous increase in the production of masks worldwide, with more than 1.5 billion masks having been disposed of during this time. The damage caused by mask pollution is a global threat; highlighting the need to dispose of discarded masks correctly. Herein, we report a recycling approach that uses discarded masks to fabricate a superhydrophobic epoxy resin/SiO2 membrane for separating emulsions. The composite has a high flux value (2123 L·m–2·h–1) and high separation efficiency (>98%). The filter maintained its excellent superhydrophobic property (WCA > 150°) after tape-peel cycles, clamping cycles with tweezers, abrasion cycles with 800 grit SiC sandpaper, pressure with fingertips, and kneading cycles. This study proposes a renewable, eco-friendly, and low-cost product, which can be used for oil spill cleanup and water purification. The filter not only removes oil from oily wastewater (such as oil spills) but also solves pollution caused by discarded masks. This study provides insights for resource recovery that may contribute to the purification of oily water emulsions.

“Functional upcycling” of polymer waste towards the design of new materials

“…As discussed earlier, the widespread application of PP FMs make them the most common waste candidate for functional upcycling. Most upcycling approaches are based on noncovalent interactions such as dip-coating, 49,52,318 electrospraying, 319 soaking, 50 drop-casting, 320,321 sputtering, 322 on-surface preparation of NPs 323 and layer-by-layer assembly. 324 The common approaches have been improved by applying supercritical CO 2 as a solvent for impregnating the active components into surface layers.…”

“…Nevertheless, the achievement of high performance for separation requires additional functionalisation of the PP surface with hydrophobic components. To date, various techniques have been adopted including the formation of composite with superhydrophobic epoxy resin/SiO 2 (Table 4(1)), 52 immobilisation of superhydrophobic fluorine-free MAF-6 (Fig. 11a and Table 4(1)), 50 or treatment with heptane (Table 4(5)).…”

“…Furthermore, depending on the polymer and intended application, the treatment methods can be categorized into surface functionalization, or bulk modification through post-polymerisation processes. In the case of surface treatment, waste can be used with minimal pre-treatment, 47,52 manually machined to centimetre-scale pieces, 53,54 extruded to produce granulates or powder, 43,55 or shaped into fibers by electrospinning. 56 Alternatively, plastic waste is dissolved/treated with reagents for functionalisation, [57][58][59] relevant organic solvents, or their mixtures such as dichloromethane, 45,59 chloroform, xylene/toluene 51,60 with the addition of ethyl acetate and hexane.…”

Polyethylenimine-Modified Glass Fiber by a Sulfur-Based Coupling Reaction for Selective Demulsification of Oil/Water Emulsions

“…In recent years, fibrous membranes with particular wettability were prepared for the separation of emulsion by combining low surface energy and high surface roughness. , Inspired by the lotus leaf, Zhu et al developed polyacrylonitrile-based membranes with hierarchical roughness via electrospinning/electrospraying technology and in situ polymerization of dopamine (DA)/polyethylenimine (PEI) . In their study, PEI provided positive charges to assemble the silica nanoparticles on the fiber surface by electrostatic interaction, thus increasing the surface roughness of fibers.…”

Synthesis of Sulfonated Carbon from Discarded Masks for Effective Production of 5-Hydroxymethylfurfural

“…Functional carbon materials, as a promising low-cost heterogeneous acid catalyst, have been used in diverse biomass transformation processes, including hydrolysis [18], dehydration [16,19], etherification, and hydrogenation reactions [5]. Various functional carbon materials have been prepared by hydrothermal carbonization, pyrolysis carbonization, and chemical carbonization with biomass-derived materials [19][20][21], sewage sludge [22], domestic garbage [23][24][25], or polymer materials (e.g., polypropylene, waste plastics) as carbon precursors [26]. Because the COVID-19 epidemic has spread all over the world in the last three years, the production and usage of face masks have increased exponentially [27,28].…”