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99,234 results on '"POLLUTANTS"'

41. Optimizing oil–water separation using fractal surfaces.

Author

Gavazzoni, Cristina, Lazzari, Davi, da Silva Ramos, Iara Patrícia, and Brito, Carolina

Subjects
*MONTE Carlo method, *SUBSTRATES (Materials science), *CONTACT angle, *POLLUTANTS, *RESEARCH methodology
Abstract

Oil has become a prevalent global pollutant, stimulating the research to improve the techniques to separate oil from water. Materials with special wetting properties—primarily those that repel water while attracting oil—have been proposed as suitable candidates for this task. However, one limitation in developing efficient substrates is the limited available volume for oil absorption. In this study, we investigate the efficacy of disordered fractal materials in addressing this challenge, leveraging their unique wetting properties. Using a combination of a continuous model and Monte Carlo simulations, we characterize the hydrophobicity and oleophilicity of substrates created through ballistic deposition (BD). Our results demonstrate that these materials exhibit high contact angles for water, confirming their hydrophobic nature while allowing significant oil penetration, indicative of oleophilic behavior. The available free volume within the substrates varies from 60% to 90% of the total volume of the substrate depending on some parameters of the BD. By combining their water and oil wetting properties with a high availability of volume, the fractal substrates analyzed in this work achieve an efficiency in separating oil from water of nearly 98%, which is significantly higher compared to micro-pillared surfaces made from the same material but lacking a fractal design. [ABSTRACT FROM AUTHOR]

Published
2025
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42. Enhanced catalytic degradation of methylene blue using self-propelled Janus micromotors: An insight into decomposing characteristics of passive and active hematite particles studded with Pt nanoparticles.

Author

Khan, Faizan, Pawak, Vishal Singh, Dugyala, Venkateshwar Rao, Mondal, Tarak, and Sabapathy, Manigandan

Subjects
*METHYLENE blue, *MICROMOTORS, *HYDROGEN peroxide, *POLLUTANTS, *SEDIMENTATION & deposition, *HEMATITE
Abstract

Recent advancements in catalytic micromotors have shown significant potential for environmental applications, yet challenges such as particle agglomeration persist. In this study, we compare the degradation of methylene blue using hematite particles fully coated with platinum and those partially decorated with platinum. The selective decoration, confirmed through techniques like EDX, FESEM, TEM, and XPS, plays a crucial role in the micromotors' behavior. The decomposition of hydrogen peroxide (H2O2) by Pt nanoparticles on one side of the hematite particles generates thrust, propelling the micromotors and enhancing their interaction with pollutant molecules. This active mobility helps counteract agglomeration, preventing the formation of irregular 3D clusters and improving catalytic efficiency. Our findings show that partially decorated particles achieve up to 85% dye removal within 90 min, outperforming fully decorated particles, which reach only 33% efficiency due to aggregation and sedimentation. These results underscore the importance of optimized surface decoration for improving the performance and stability of catalytic systems in pollutant degradation. [ABSTRACT FROM AUTHOR]

Published
2024
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48. Dripping with promise.

Author

Lawton, Graham

Subjects
*SCIENTIFIC knowledge, *POLLUTANTS, *GLOBAL warming, *MATERIALS science, *EXTRACELLULAR fluid, *PERSPIRATION
Abstract

The article discusses the potential of sweat analysis for health monitoring, particularly in athletes. Sweat contains biomolecules that can provide insights into our health, and wearable sweat sensors are being developed to collect and analyze this data. The article highlights the various applications of sweat analysis, from monitoring hydration levels in athletes to detecting performance-enhancing drugs and inflammatory conditions. Researchers are exploring the use of sweat as a diagnostic biofluid for a wide range of health conditions, showing promise for future advancements in health monitoring technology. [Extracted from the article]

Published
2024
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49. Studying single-electron traps in newly fabricated Skipper-CCDs for the Oscura experiment using the pocket-pumping technique.

Author

Perez Garcia, Santiago Ezequiel, Cervantes Vergara, Brenda Aurea, Cruz Estrada, Juan, Holland, Stephen, Rodrigues Ferreira Maltez, Dario Pablo, and Tiffenberg, Javier

Subjects
*MONTE Carlo method, *ELECTRONIC probes, *GETTERING, *DARK matter, *POLLUTANTS
Abstract

Understanding and characterizing very low-energy (∼ eV) background sources is a must in rare-event searches. Oscura, an experiment aiming to probe electron recoils from sub-GeV dark matter using a 10 kg skipper-CCD detector, has recently fabricated its first two batches of sensors. In this work, we present the characterization of defects/contaminants identified in the buried-channel region of these newly fabricated skipper-CCDs. These defects/contaminants produce deferred charge from trap emission in the images next to particle tracks, which can be spatially resolved due to the sub-electron resolution achieved with these sensors. Using the trap-pumping technique, we measured the energy and cross section associated with these traps in three Oscura prototype sensors from different fabrication batches which underwent different gettering methods during fabrication. Results suggest that the type of defects/contaminants is more closely linked to the fabrication batch rather than to the gettering method used. The exposure-dependent single-electron rate (SER) of one of these sensors was measured ∼ 100 m underground, yielding (1.8 ± 0.3) × 10 − 3 e − /pix/day at 131 K. The impact of the identified traps on the measured exposure-dependent SER is evaluated via a Monte Carlo simulation. Results suggest that the exposure-dependent SER of Oscura prototype sensors would be lower in lower background environments as expected. [ABSTRACT FROM AUTHOR]

Published
2024
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