Transforming waste polypropylene face masks into S-doped porous carbon as the cathode electrode for supercapacitors

Abstract

The spread of COVID-19 has led to an explosive increase in the number of waste polypropylene face masks worldwide, landfill and incineration of which will cause serious pollution and resource waste. This study aims to develop a new method for the safe and high-added value reuse of materials for polypropylene face masks based on carbonization of porous polymer. The waste masks were first sulfonated in an autoclave, then used as carbon source and turned into a dense hollow fiber porous structure after a one-step heat treatment. This porous structure has a high specific capacitance, namely 328.9 F g −1 at a current density of 1 A g −1. Besides, the assembled solid-state capacitor possesses a good energy density of 10.4 W h kg −1 at a power density of 600 W kg −1 , and excellent cycling stability with a capacitance retention rate of 81.1% after 3000 cycles. These findings indicate that the novel carbonization technology in this study can not only be used to obtain high-performance supercapacitor electrode materials but also provide a new idea for the recycling and utilization of wastes such as medical devices.

Review of the valorization options for the proper disposal of face masks during the COVID-19 pandemic

“…Carbonization is an energy-saving, emission friendly, controllable, and simple process that can produce various carbon-based materials, such as activated carbon, carbon fiber, carbon sphere, graphite, and carbon nanomaterials ( Bazargan and McKay, 2012 , Chen et al, 2020 ). Face mask waste mainly contains polypropylene, which is an interesting waste for carbonization ( Hu and Lin, 2021 , Joseph et al, 2021 ). Meanwhile, high temperatures involved in the carbonization process can act as a disinfectant and destroy viruses and other contaminates.…”

“…Meanwhile, high temperatures involved in the carbonization process can act as a disinfectant and destroy viruses and other contaminates. The potential of carbonizing face mask waste in the utilization of supercapacitors ( Hu and Lin, 2021 , Zhu et al, 2021 ) and adsorbents ( Anastopoulos and Pashalidis, 2021 ) has been recently investigated.…”

Synergistic effects of B/S co-doped spongy-like hierarchically porous carbon for a high performance zinc-ion hybrid capacitor

“…4(a)) can be fitted into four independent peaks, including C–C/CC (∼284.5 eV), C–OH (∼285.7 eV), CO/C–S (∼287.4 eV) and O–CO (∼290.2 eV), respectively. The abundant C–OH bond in B 2 S 0 C and B 2 S 3 C was conducive to increasing the hydrophilicity of the electrolyte at the interface of B 2 S 0 C and B 2 S 3 C, which was verified by the small contact angle of B 2 S 0 C and B 2 S 3 C. The C–S bond was attributed to the introduction of S atoms into B 0 S 3 C and B 2 S 3 C. 40,41 The B 1s spectrum (Fig. 4(b)) contains four peaks, such as BC 3 (∼188.9 eV), BC 2 O (∼190.2 eV), B–O (∼191.4 eV) and BCO 2 (∼192.2 eV).…”

Waste Face Surgical Mask Transformation into Crude Oil and Nanostructured Electrocatalysts for Fuel Cells and Electrolyzers

“…Surgical masks are mostly composed of plastic materials that could be transformed into value‐added products (VAPs). Particularly, surgical masks have been transformed into crude oil, biochar, and other plastic materials [11,17,19–21,23] . In this work, surgical masks have been characterized through solid‐state NMR spectroscopy to identify the composition, which is predominantly PP.…”

“…investigated the thermodynamic characteristics of pyrolysis of waste medical surgical mask rope in the inert atmosphere and compared the obtained products with those of conventional plastics [22] . Recently, Hu and Lin carbonized the waste polypropylene face masks into carbonaceous char, which was used as a cathode material for supercapacitor and provided promising specific capacitance of 328.9 F g −1 at a current density of 1 A g −1 [23] …”