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- Feng, Jicheng, et al.
(författare)
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General Approach to the Evolution of Singlet Nanoparticles from a Rapidly Quenched Point Source
- 2016
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:1, s. 621-630
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Tidskriftsartikel (refereegranskat)abstract
- Among the numerous point vapor sources, microsecond-pulsed spark ablation at atmospheric pressure is a versatile and environmentally friendly method for producing ultrapure inorganic nanoparticles ranging from singlets having sizes smaller than 1 nm to larger agglomerated structures. Due to its fast quenching and extremely high supersaturation, coagulational growth already begins at the atomic scale at room temperature. On the basis of this knowledge, we develop a simple semiempirical yet versatile model for predicting the size distribution of singlet particles as a function of the process conditions. The model assumes that a plume of a turbulent aerosol flow flares out from a concentrated point source, eventually reaching the walls of the confinement where a fraction of the particles is deposited. Despite the complexity of the entire process, the concentration and size evolution of particles can be adequately described by a first-order differential equation accounting for coagulation, turbulent dilution, and diffusional deposition to the walls. The model provides a simple and practical tool that can generally be used to design and control point vapor source reactors for the synthesis of singlets with tunable sizes starting from that of single atoms.
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| 4. |
- Hedmer, Maria, et al.
(författare)
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Exposure and Emission Measurements During Production, Purification, and Functionalization of Arc-Discharge-Produced Multi-walled Carbon Nanotubes.
- 2014
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 1475-3162. ; 58:3, s. 355-379
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Tidskriftsartikel (refereegranskat)abstract
- Background: The production and use of carbon nanotubes (CNTs) is rapidly growing. With increased production, there is potential that the number of occupational exposed workers will rapidly increase. Toxicological studies on rats have shown effects in the lungs, e.g. inflammation, granuloma formation, and fibrosis after repeated inhalation exposure to some forms of multi-walled CNTs (MWCNTs). Still, when it comes to health effects, it is unknown which dose metric is most relevant. Limited exposure data for CNTs exist today and no legally enforced occupational exposure limits are yet established. The aim of this work was to quantify the occupational exposures and emissions during arc discharge production, purification, and functionalization of MWCNTs. The CNT material handled typically had a mean length <5 μm. Since most of the collected airborne CNTs did not fulfil the World Health Organization fibre dimensions (79% of the counted CNT-containing particles) and since no microscopy-based method for counting of CNTs exists, we decided to count all particle that contained CNTs. To investigate correlations between the used exposure metrics, Pearson correlation coefficient was used.
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| 7. |
- Hontañón, Esther, et al.
(författare)
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A green dry route for antibacterial nanofinishing of textiles
- 2015
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Ingår i: Proceedings of the World Congress on New Technologies (NewTech 2015).
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Konferensbidrag (refereegranskat)abstract
- In this paper, an aerosol-based process is proven for imparting antibacterial property to textiles. Nanoparticles of copper and silver are produced by means of glow discharge between two electrodes in nitrogen at atmospheric pressure and passed through fabrics of cotton and polyester which act as filter media. The bactericidal performance of the nanofinished fabrics is assessed against Gram-positive Staphylococcus aureus and Gramnegative Klebsiella pneumonia bacteria. Nanoparticle loads of about 0.3 g/m2 (~ 0.2 wt %) give strong antibacterial activity to the fabrics regardless of particle composition and size. Higher loads do not enhance the bactericide property but affect the colour and hand feel of the fabrics. Cotton and polyester fabrics with low loads (<0.3 g/m2) of small silver nanoparticles (<10 nm) show different bactericidal behaviour. Polyester fabrics attain good antibacterial activity for SA and KP, which is retained (KP) or decreases (SA) after washing. Cotton fabrics show hardly bactericidal property but, in some cases, it increases after washing.
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