Pyrolysis behavior, kinetics, and thermodynamics of waste pharmaceutical blisters under CO2 atmosphere.

The disastrous impact of COVID-19 pandemic has caused a significantly increased production and use of pharmaceutical drugs, which is accompanied by the rapid generation of waste pharmaceutical blisters (WPBs). Nonetheless, its treatment has not gained appropriate attentions and a perceptible process development was not achieved. In this study, the WPBs pyrolysis in CO2 atmosphere was conducted as well as the thermodynamics and kinetics were investigated. The thermogravimetric analysis revealed that the WPBs decomposition could be divided into two stages of 25 - 365 °C and 365 - 900 °C with mass loss of 56.5 - 60.5 wt% and 22.5 - 25.9 wt%, respectively. Fourier-transform infrared spectroscopy analysis indicated the dechlorination process initiating at ∼300 °C. The simultaneous asymmetric stretching of HCl and stretching vibration of C-Cl bond was detected in the range of 2600 - 3250 cm-1 and 660 - 750 cm-1, respectively. The dechlorination reactions were almost complete at ∼520 °C and minor peaks (2900 -3100 cm-1) due to C-H vibrations were observed. Gas chromatography-mass spectrometry analysis indicated that the evolved products included alkanes, benzene, olefin, as well as HCl. The cycloalkenes content significantly increased during the second conversion stage, implying the addition reactions between alkanes and olefins. The apparent activation energy was calculated using three model-free methods and the values from Flynn-Wall-Ozawa model increased from 142.0 to 255.8 kJ·mol-1 with an average value of 147.4 kJ·mol-1. The methods of Coats-Redfern as well as Malek were applied to determine the reaction mechanism. The one-dimensional diffusion model was more reliable to describe the WPBs pyrolysis. This study will represent a significant reference case for the thermochemical conversion of multilayer packing waste and facing the increasing demand for the medical waste recycling.

COVID-19 Related Early Google Search Behavior and Health Communication in the United States: Panel Data Analysis on Health Measures.

The COVID-19 outbreak at the end of December 2019 spread rapidly all around the world. The objective of this study is to investigate and understand the relationship between public health measures and the development of the pandemic through Google search behaviors in the United States. Our collected data includes Google search queries related to COVID-19 from 1 January to 4 April 2020. After using unit root tests (ADF test and PP test) to examine the stationary and a Hausman test to choose a random effect model, a panel data analysis is conducted to investigate the key query terms with the newly added cases. In addition, a full sample regression and two sub-sample regressions are proposed to explain: (1) The changes in COVID-19 cases number are partly related to search variables related to treatments and medical resources, such as ventilators, hospitals, and masks, which correlate positively with the number of new cases. In contrast, regarding public health measures, social distancing, lockdown, stay-at-home, and self-isolation measures were negatively associated with the number of new cases in the US. (2) In mild states, which ranked one to twenty by the average daily new cases from least to most in 50 states, the query terms about public health measures (quarantine, lockdown, and self-isolation) have a significant negative correlation with the number of new cases. However, only the query terms about lockdown and self-isolation are also negatively associated with the number of new cases in serious states (states ranking 31 to 50). Furthermore, public health measures taken by the government during the COVID-19 outbreak are closely related to the situation of controlling the pandemic.

A State-of-the-Art Review of Radioactive Decontamination Technologies: Facing the Upcoming Wave of Decommissioning and Dismantling of Nuclear Facilities

The average share of nuclear energy in electricity production is expected to increase under the background of the global pursuit towards carbon neutrality. Conjugating with its rapid development, the wave of decommissioning and dismantling (D&D) of nuclear facilities is coming. The surface decontamination is a prerequisite to D&D, which will make it easier and reduce the volume of radioactive wastes. However, there are no comprehensive studies on the decontamination methods, which is not helpful for the sustainable development of nuclear energy and environment protection. Therefore, in this work, the current status and future trends of global energy and nuclear energy are first analyzed. Then, various decontamination approaches are comparatively studied, including cleaning mechanisms, application subjects, and intrinsic advantages and disadvantages. Finally, the criteria and factors for selecting a decontamination process, the challenges, and future studies are directed. Among the mechanical methods, laser-based cleaning is high-speed, having automation ability, and thus is promising, although it creates a dust and airborne contaminant hazard. In further studies, factors such as selecting a proper laser facility, optimizing operating parameters, and designing a high-efficiency dust collection system could be studied. Regarding the chemical method, chemical gels are good for decontaminating complex shapes and vertical and overhead surfaces. In addition, they can enhance other decon agents’ efficiency by improving contact time. However, the formulation of colloidal gels is complex and no gel type is useful for all contaminants. Therefore, novel and versatile gels need be developed to enlarge their application field. Combining various decontamination methods will often have better results and thus a reasonable and effective combination of these decontamination methods has become the main direction.