Upcycling face mask wastes generated during COVID-19 into value-added engineering materials: A review.

Billions of disposable face masks (i.e., single-use masks) are used and discarded worldwide monthly due to the COVID-19 outbreak. The immethodical disposal of these polymer-based wastes containing non-biodegradable constituents (e.g., polypropylene) has provoked marked and severe damage to the ecosystem. Meanwhile, their ever-growing usage significantly strains the present-day waste management measures such as landfilling and incineration, resulting in large quantities of used face-covering masks landing in the environment as importunate contaminants. Hence, alternative waste management strategies are crucially demanded to decrease the negative impacts of face mask contamination. In this venue, developing high-yield, effective, and green routes toward recycling or upcycling face mask wastes (FMWs) into value-added materials is of great importance. While existing recycling processes assist the traditional waste management, they typically end up in materials with downgraded physicochemical, structural, mechanical, and thermal characteristics with reduced values. Therefore, pursuing potential economic upcycling processes would be more beneficial than waste disposal and/or recycling processes. This paper reviews recent advances in the FMWs upcycling methods. In particular, we focus on producing value-added materials via various waste conversion methods, including carbonization (i.e., extreme pyrolysis), pyrolysis (i.e., rapid carbonization), catalytic conversion, chemical treatment, and mechanical reprocessing. Generally, the upcycling methods are promising, firming the vital role of managing FMWs' fate and shedding light on the road of state-of-the-art materials design and synthesis.

Facemasks and ferrous metallurgy: improving gasification reactivity of low-volatile coals using waste COVID-19 facemasks for ironmaking application.

The global pandemic response to COVID-19 has led to the generation of huge volumes of unrecyclable plastic waste from single use disposable face coverings. Rotary hearth furnaces can be used to recover Zn and Fe from non-recyclable steelmaking by-product dusts, and waste plastic material such as facemasks could be utilized as a supplementary reductant for the rotary hearth furnace (RHF), but their fibrous form makes milling and processing to appropriate sizing for RHF application extremely challenging. A scalable method of grinding facemasks to powder by melting and mixing with Welsh coal dust reported herein provides a solution to both environmental challenges. The melt-blended PPE/coal dust shows a dramatically improved CO2 gasification reactivity (Ea = 133-159 kJmol-1) when compared to the untreated coal (Ea = 183-246 kJmol-1), because of improved pore development in the coal during the pyrolysis stage of heating and the catalytic activity of the CaO based ash present in the facemask plastic. The results are promising for the application of waste facemasks in recycling steelmaking by-product dusts in rotary hearth furnaces and may also be suitable for direct injection to the blast furnace subject to further study.

Green-based active packaging: Opportunities beyond COVID-19, food applications, and perspectives in circular economy-A brief review.

The development of biodegradable packaging, based on agro-industrial plant products and by-products, can transform waste into products with high added value and reduce the use of conventional nonrenewable packaging. Green-based active packaging has a variety of compounds such as antimicrobials, antioxidants, aromatics, among others. These compounds interact with packaged products to improve food quality and safety and favor the migration of bioactive compounds from the polymeric matrix to food. The interest in the potential hygienic-sanitary benefit of these packages has been intensified during the COVID-19 pandemic, which made the population more aware of the relevant role of packaging for protection and conservation of food. It is estimated that the pandemic scenario expanded food packaging market due to shift in eating habits and an increase in online purchases. The triad health, sustainability, and circular economy is a trend in the development of packaging. It is necessary to minimize the consumption of natural resources, reduce the use of energy, avoid the generation of waste, and emphasize the creation of social and environmental values. These ideas underpin the transition from the emphasis on the more subjective discourse to the emphasis on the more practical method of thinking about the logic of production and use of sustainable packaging. Presently, we briefly review some trends and economic issues related to biodegradable materials for food packaging; the development and application of bio-based active films; some opportunities beyond COVID-19 for food packaging segment; and perspectives in circular economy.

Cuckoo optimization algorithm in reverse logistics: A network design for COVID-19 waste management.

Today, reverse logistics (RL) is one of the main activities of supply chain management that covers all physical activities associated with return products (such as collection, recovery, recycling and destruction). In this regard, the designing and proper implementation of RL, in addition to increasing the level of customer satisfaction, reduces inventory and transportation costs. In this paper, in order to minimize the costs associated with fixed costs, material flow costs, and the costs of building potential centres, a complex integer linear programming model for an integrated direct logistics and RL network design is presented. Due to the outbreak of the ongoing global coronavirus pandemic (COVID-19) at the beginning of 2020 and the consequent increase in medical waste, the need for an inverse logistics system to manage waste is strongly felt. Also, due to the worldwide vaccination in the near future, this waste will increase even more and careful management must be done in this regard. For this purpose, the proposed RL model in the field of COVID-19 waste management and especially vaccine waste has been designed. The network consists of three parts - factory, consumers' and recycling centres - each of which has different sub-parts. Finally, the proposed model is solved using the cuckoo optimization algorithm, which is one of the newest and most powerful meta-heuristic algorithms, and the computational results are presented along with its sensitivity analysis.