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1.
Materials (Basel) ; 15(4)2022 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-35207912

RESUMO

After more than two years wearing surgical masks due to the COVID-19 pandemic, used masks have become a significant risk for ecosystems, as they are producing wastes in huge amounts. They are a potential source of disturbance by themselves and as microplastic contamination in the water system. As 5500 tons of face masks are estimated to be used each year, there is an urgent need to manage them according to the circular economy principles and avoid their inadequate disposal. In this paper, surgical wear masks (WM), without any further pretreatment, have been introduced as addition to mortars up to 5% in the weight of cement. Mechanical and microstructural characterization have been carried out. The results indicate that adding MW to the cement supposes a decrease in the properties of the material, concerning both strength and durability behavior. However, even adding a 5% of WM in weight of cement, the aspect of the mortars is quite good, the flexural strength is not significantly affected, and the strength and durability parameters are maintained at levels that-even lower than the reference-are quite reasonable for use. Provided that the worldwide production of cement is around 4.1 Bt/year, the introduction of a 5% of WM in less than 1% of the cement produced, would make it possible to get rid of the mask waste being produced.

2.
Front Chem ; 8: 743, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33195015

RESUMO

Despite serious health and environmental burdens associated with air pollution by NOx, the emission ceilings have been systematically exceeded in big European cities for several years. Photocatalytic technology can be an efficient solution for the removal of chemical air pollutants. Because diesel engine exhaust is the main source of NOx emissions, the application of a photocatalyst onto road pavement appears to be an effective NOx abatement method due to the large surface area, proximity to the emission source, and relatively good solar irradiance. Several laboratory-scale studies provided evidence demonstrating that most harmful contaminants can be readily mineralized. Furthermore, several projects were aiming to scale up this technology to pilot and real scales. Although the photocatalytic performances of selected materials in real urban environments were determined in some of these studies, the data are not conclusive for evaluating the overall performance because other material characteristics relevant to their functionality were not assessed. The lack of conformity criteria suitable for the evaluation of the overall performance of photocatalytic pavement under real operational conditions has generated skepticism and mistrust among public authorities and relevant stakeholders, which constrains the widespread implementation of this promising technology. In this context, the project LIFE-Photoscaling was focused on developing a new holistic conceptual framework to assess the photocatalytic pavement performance using the decision tool "Photoscaling Decision Maker" based on a set of quantitative indicators. For this purpose, a large volume of data obtained for 10 types of photocatalytic pavement materials was systemized on both the laboratory and pilot plant scales and three main indicators were defined: (1) photocatalytic performance effectiveness, (2) intrinsic performance, and (3) undesired secondary effects. Each top-level indicator includes several low-level subindicators associated with specific material characteristics. Finally, the ranges of the main indicators and subindicators and methods for their assessment were determined. These methods include standard, adopted, and original characterization techniques, which were selected based on the criteria such as simplicity, cost- and time-effectiveness, and relevance regarding the operational conditions.

3.
Environ Sci Pollut Res Int ; 26(36): 36088-36095, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30721438

RESUMO

In the recent past, the NOx removal efficiency of photocatalytic materials has been subject of many studies with promising results. However, many of these studies involve laboratory tests carried out under standardized climatic exposure conditions, often not representative of the real-world environment. With the aim to bridge this gap, selected photocatalytic materials have been applied to different substrates in outdoor demonstrator platforms at pilot scale as part of the project LIFE-PHOTOSCALING. The paper presents the results of in situ measurements of NOx removal efficiency of the materials, performed during 17 months. Statistical models accounting for the influence of exposure time and relevant environmental variables are derived. They suggest that photocatalytic emulsions on the tested asphalt experience a significant loss of activity over time irrespective of climatic conditions. The efficiency of photocatalytic slurries on asphalt and of concrete tiles, with the photocatalyst applied on surface or in bulk, mainly depends on substrate humidity.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Hidrocarbonetos/química , Modelos Teóricos , Óxidos de Nitrogênio/análise , Emulsões , Umidade , Fotoquímica , Projetos Piloto
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