Synthesis of the cathode and anode materials from discarded surgical masks for high-performance asymmetric supercapacitors

A review of disposable facemasks during the COVID-19 pandemic: A focus on microplastics release

The COVID-19 epidemic seriously threats the human society and provokes the panic of the public. Personal Protective Equipment (PPE) are widely utilized for frontline health workers to face the ongoing epidemic, especially disposable face masks (DFMs) to prevent airborne transmission of coronavirus. The overproduction and massive utilization of DFMs seriously challenge the management of plastic wastes. A huge amount of DFMs are discharged into environment, potentially induced the generation of microplastics (MPs) owing to physicochemical destruction. The MPs release will pose severe contamination burden on environment and human. In this review, environmental threats of DFMs regarding to DFMs fate in environment and DFMs threats to aquatic and terrestrial species were surveyed. A full summary of recent studies on MPs release from DFMs was provided. The knowledge of extraction and characterizations of MPs, the release behavior, and potential threats of MPs derived from DFMs was discussed. To confront the problem, feasible strategies for control DFMs pollution were analyzed from the perspective of source control and waste management. This review provides a better understanding the threats, fate, and management of DFMs linked to COVID-19 pandemic.

High Performance Asymmetric Supercapacitor Based on Hierarchical Carbon Cloth In Situ Deposited with h-WO3 Nanobelts as Negative Electrode and Carbon Nanotubes as Positive Electrode

Urchin-like tungsten oxide (WO₃) microspheres self-assembled with nanobelts are deposited on the surface of the hydrophilic carbon cloth (CC) current collector via hydrothermal reaction. The WO₃ nanobelts in the urchin-like microspheres are in the hexagonal crystalline phase, and their widths are around 30–50 nm. The resulted hierarchical WO₃/CC electrode exhibits a capacitance of 3400 mF/cm² in H₂SO₄ electrolyte in the voltage window of −0.5~0.2 V, which makes it an excellent negative electrode for asymmetric supercapacitors. To improve the capacitive performance of the positive electrode and make it comparable with that of the WO₃/CC electrode, both the electrode material and the electrolyte have been carefully designed and prepared. Therefore, the hydrophilic CC is further coated with carbon nanotubes (CNTs) to create a hierarchical CNT/CC electrode via a convenient flame synthesis method, and a redox-active electrolyte containing an Fe²⁺/Fe ³⁺ couple is introduced into the half-cell system as well. As a result, the high performance of the asymmetric supercapacitor assembled with both the asymmetric electrodes and electrolytes has been realized. It exhibits remarkable energy density as large as 403 μW h/cm² at 15 mW/cm² and excellent cyclic stability after 10,000 cycles.

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

The COVID-19 pandemic has affected not only human health and economies but also the environment due to the large volume of waste in the form of discarded personal protective equipment. The remarkable increase in the global usage of face masks, which mainly contain polypropylene, and improper waste management have led to a serious environmental challenge called microplastic pollution. Potential practices for waste management related to waste valorization of discarded face masks as the major type of waste during the COVID-19 pandemic are explored in this study. Recommendations based on governmental practices, situation of state facilities, and societal awareness and engagement applicable to emergency (including COVID-19 pandemic) and postpandemic scenarios are offered while considering potential solutions and available waste management practices in different countries during emergency conditions. However, multicriteria decision making for a country must determine the optimal solution for waste management on the basis of all affecting factors. Awareness of scientific, governments, and communities worldwide will successfully eradicate this important environmental issue.