ABSTRACT
The worldwide outbreak of the coronavirus pandemic (COVID-19) and other emerging infections are difficult and sometimes impossible to treat, making them one of the major public health problems of our time. It is noteworthy that Ag-based semiconductors can help orchestrate several strategies to fight this serious societal issue. In this work, we present the synthesis of α-Ag2WO4, β-Ag2MoO4, and Ag2CrO4 and their immobilization in polypropylene in the amounts of 0.5, 1.0, and 3.0 wt %, respectively. The antimicrobial activity of the composites was investigated against the Gram-negative bacterium Escherichia coli, the Gram-positive bacterium Staphylococcus aureus, and the fungus Candida albicans. The best antimicrobial efficiency was achieved by the composite with α-Ag2WO4, which completely eliminated the microorganisms in up to 4 h of exposure. The composites were also tested for the inhibition of SARS-CoV-2 virus, showing antiviral efficiency higher than 98% in just 10 min. Additionally, we evaluated the stability of the antimicrobial activity, resulting in constant inhibition, even after material aging. The antimicrobial activity of the compounds was attributed to the production of reactive oxygen species by the semiconductors, which can induce high local oxidative stress, causing the death of these microorganisms.
ABSTRACT
The worldwide outbreak of the coronavirus pandemic (COVID-19) and other emerging infections are difficult and sometimes impossible to treat, making them one of the major public health problems of our time. It is noteworthy that Ag-based semiconductors can help orchestrate several strategies to fight this serious societal issue. In this work, we present the synthesis of α-Ag2WO4, ß-Ag2MoO4, and Ag2CrO4 and their immobilization in polypropylene in the amounts of 0.5, 1.0, and 3.0 wt %, respectively. The antimicrobial activity of the composites was investigated against the Gram-negative bacterium Escherichia coli, the Gram-positive bacterium Staphylococcus aureus, and the fungus Candida albicans. The best antimicrobial efficiency was achieved by the composite with α-Ag2WO4, which completely eliminated the microorganisms in up to 4 h of exposure. The composites were also tested for the inhibition of SARS-CoV-2 virus, showing antiviral efficiency higher than 98% in just 10 min. Additionally, we evaluated the stability of the antimicrobial activity, resulting in constant inhibition, even after material aging. The antimicrobial activity of the compounds was attributed to the production of reactive oxygen species by the semiconductors, which can induce high local oxidative stress, causing the death of these microorganisms.
ABSTRACT
Brazil is the fourth largest producer of plastic waste in the world. Among all the challenges the country had faced in the development of public policies for the banning of single-use plastics, the new coronavirus pandemic scenario determined the suspension of these laws indefinitely. In 2020, Brazil became the global epicenter of COVID-19. This scenario changed the habit and behavior of Brazilian consumers, who increased the consumption of plastics due to their importance in applications as protective material. The country also has social problems related to waste management that depend mainly on waste pickers. These workers need social visibility and protection not only to face the current health crisis but also to guarantee their income and survival. This work aims to discuss the increase in single-use plastics that are not intended for recycling and the respective environmental, economic, and social impacts for the country. We demonstrate the lack of data on waste management in Brazil and highlight the importance of the social inclusion of waste pickers for a circular economy. Especially after the change of scenario with the COVID-19 pandemic, the country must have adequate planning and improvements in waste management, recycling programs, and political intervention to raising awareness among the population and guaranteeing social rights for waste pickers.
ABSTRACT
Brazil is the fourth largest producer of plastic waste in the world. Among all the challenges the country had faced in the development of public policies for the banning of single-use plastics, the new coronavirus pandemic scenario determined the suspension of these laws indefinitely. In 2020, Brazil became the global epicenter of COVID-19. This scenario changed the habit and behavior of Brazilian consumers, who increased the consumption of plastics due to their importance in applications as protective material. The country also has social problems related to waste management that depend mainly on waste pickers. These workers need social visibility and protection not only to face the current health crisis but also to guarantee their income and survival. This work aims to discuss the increase in single-use plastics that are not intended for recycling and the respective environmental, economic, and social impacts for the country. We demonstrate the lack of data on waste management in Brazil and highlight the importance of the social inclusion of waste pickers for a circular economy. Especially after the change of scenario with the COVID-19 pandemic, the country must have adequate planning and improvements in waste management, recycling programs, and political intervention to raising awareness among the population and guaranteeing social rights for waste pickers.
ABSTRACT
The current unprecedented coronavirus pandemic (COVID-19) is increasingly demanding advanced materials and new technologies to protect us and inactivate SARS-CoV-2. In this research work, we report the manufacture of Ag3PO4 (AP)/polypropylene (PP) composites using a simple method and also reveal their long-term anti-SARS-CoV-2 activity. This composite shows superior antibacterial (against Staphylococcus aureus and Escherichia coli) and antifungal activity (against Candida albicans), thus having potential for a variety of technological applications. The as-manufactured materials were characterized by XRD, Raman spectroscopy, FTIR spectroscopy, AFM, UV-vis spectroscopy, rheology, SEM, and contact angle to confirm their structural integrity. Based on the results of first-principles calculations at the density functional level, a plausible reaction mechanism for the initial events associated with the generation of both hydroxyl radical â¢OH and superoxide radical anion â¢O2- in the most reactive (110) surface of AP was proposed. AP/PP composites proved to be an attractive avenue to provide human beings with a broad spectrum of biocide activity.