Supercritical CO2 sterilization: An effective treatment to reprocess FFP3 face masks and to reduce waste during COVID-19 pandemic

A review on medical waste treatment in COVID-19 pandemics: Technologies, managements and future strategies

Since the outbreak of COVID-19 few years ago, the increasing of the number of medical waste has become a huge issue because of their harmful impact to environment. A major concern associated to the limitation of technologies for dealing with medical waste, especially conventional technologies, are overcapacities since pandemic occurs. Moreover, the outbreak of new viruses from post COVID-19 should become a serious attention to be prevented not only environmental issues but also the spreading of viruses to new pandemic near the future. The high possibility of an outbreak of new viruses and mutation near the future should be prevented based on the experience associated with the SARS-CoV-2 virus in the last 3 yr. This review presented information and strategies for handling medical waste during the outbreak of COVID-19 and post-COVID-19, and also information on the current issues related to technologies, such as incineration, pyrolysis/gasification, autoclaves and microwave treatment for the dealing with high numbers of medical waste in COVID-19 to prevent the transmission of SARS-CoV-2 virus, their advantages and disadvantages. Plasma technology can be considered to be implemented as an alternative technology to deal with medical waste since incinerator is usually over capacities during the pandemic situation. Proper treatment of specific medical waste in pandemics, namely face masks, vaccine vials, syringes, and dead bodies, are necessary because those medical wastes are mediums for transmission of the SARS-CoV-2 virus. Furthermore, emission controls from incinerator and plasma are necessary to be implemented to reduce the high concentration of CO2, NOx, and VOCs during the treatment. Finally, future strategies of medical waste treatment in the perspective of potential outbreak pandemic from new mutation viruses are discussed in this review paper.Implications: Journal of the air and waste management association may consider our review paper to be published. In this review, we give important information related to the technologies, managements and strategies for handling the medical waste and control the transmission of SARS-CoV-2 virus, starting from proper technology to control the high number of medical waste, their pollutants and many strategies for controlling the spreading of SARS-CoV-2 virus. Moreover, this review also describes some strategies associated with control the transmission not only the SARS-CoV-2 virus but also the outbreak of new viruses near the future.

Personal protective equipment waste management behavior of undergraduates in Xi'an City based on extended theory of value-identity-personal norm model

The COVID-19 pandemic has changed people's lives, with the most prominent change being the use of Personal Protective Equipment (PPE). In this study, we used the extended Value-Identity-Personal (VIP) norm model to empirically analyze the influencing factors of Pro-Environmental Behavior (PEB) among college students in Xi 'an, China, while considering the usage of PPE as an example of PEB. We proposed nine hypothetical questions, and the VIP model was established through the SmartPLS software to test the valid questionnaires of 414 college students. The verification results indicated that all the nine hypotheses were supported statistically, with personal environmental social responsibility and personal norms showing the most significant direct impact on PEB; notably, personal norms were also strongly influenced by environmental personal social responsibility. Biosphere values affected PEB indirectly, through self-identity and individual norms. This study proposes viable countermeasures and suggestions for college students to improve PEB; our findings can serve as a reference for policymakers and stakeholders to ensure the effective waste management of personal safety equipment.

Ozone Decontamination of Medical and Nonmedical Devices: An Assessment of Design and Implementation Considerations

The control of infectious diseases can be improved via carefully designed decontamination equipment and systems. Research interest in ozone (a powerful antimicrobial agent) has significantly increased over the past decade. The COVID-19 pandemic has also instigated the development of new ozone-based technologies for the decontamination of personal protective equipment, surfaces, materials, and indoor environments. As this interest continues to grow, it is necessary to consider key factors affecting the applicability of lab-based findings to large-scale systems utilizing ozone. In this review, we present recent developments on the critical factors affecting the successful deployments of industrial ozone technologies. Some of these include the medium of application (air or water), material compatibility, efficient circulation and extraction, measurement and control, automation, scalability, and process economics. We also provide a comparative assessment of ozone relative to other decontamination methods/sterilization technologies and further substantiate the necessity for increased developments in gaseous and aqueous ozonation. Modeling methodologies, which can be applied for the design and implementation of ozone contacting systems, are also presented in this review. Key knowledge gaps and open research problems/opportunities are extensively covered including our recommendations for the development of novel solutions with industrial importance.

Development of chlorine dioxide sustained-release device using carboxymethyl cellulose-polyvinyl alcohol-β-cyclodextrin ternary hydrogel and a new sustained-release kinetic model

Owing to unique physiochemical and biological properties as well as the ability to be combined with a wide variety of materials for both biocompatibility and hydrophilia, carboxymethyl cellulose (CMC) is an excellent choice as a carrier. Loading Chlorine dioxide (ClO₂) into biodegradable carrier for its good disinfection performance and high safety factors has attracted significantattention. Therefore, in this study, we used ClO₂ as a model drug, and a sustained-ClO₂-gas-release gel was developed from degradable materials, such as carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and β-cyclodextrin (βCD), through a simple and benign crosslinking strategy. Notably, the gel had sustained-release property in a wide temperature range of 4-35 ℃ and released ClO₂ gas effectively for more than 30 days. Furthermore, a loss factor was proposed based on the incomplete release of the drug in the sustained release process to a chieve a good fit with the gas diffusion process. A new diffusion model was designed based on the Korsmeyer-Peppas model, and an excellent fit was obtained. This sustained-ClO₂-gas-release gel provides theoretical and technical guidance for the development of sustained-disinfectant-release agents for use in space and offers new insights into the sustained release model of skeleton-soluble hydrogels.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10570-023-05070-6.

Dry Heat as a Potential Decontamination Method on the Filtration Efficiency of Filtering Facepiece Respirators

Filtering facepiece respirators have been widely used in the fields of occupational health and public hygiene, especially during the COVID-19 pandemic. In particular, disposable respirators have been in high demand, and the waste generated from these disposable products poses a problem for the environment. Here, we aimed to test a practical decontamination method to allow for the reuse of KN95 respirators. In this study, three types of KN95 respirators were heated at 80 °C and 90 °C for different durations (15 min, 30 min, 45 min, 1 h, 2 h, 3 h, 4 h, 6 h, 8 h, 10 h, and 24 h). The filtration efficiencies of the tested KN95 respirators before and after heating were measured, and the changes in microstructure were imaged with a scanning electron microscope (SEM). In addition, a neural network model based on the nonlinear autoregressive with external input (NARX) to predict the filtration efficiency of the KN95 respirator was established. The results show that the temperature and time of dry heating affected particle prevention. The higher the temperature and the longer the heating time, the more obvious the decline in the filtration efficiency of the respirators. When the heating temperature reached 100 °C, the respirator may be no longer suitable for reuse. These results show that a dry heat temperature between 70 °C and 90 °C, and a heating time between 30 min and 2 h is assumed to be a suitable and effective decontamination method for respirators.