Dustiness test of nanopowders using a standard rotating drum with a modified sampling train

Tsai, Chuen Jinn; Wu, Chien Hsien; Leu, Ming Long; Chen, Sheng Chieh; Huang, Cheng; Tsai, Perng Jy; Ko, Fu Hsiang

doi:10.1007/s11051-008-9453-5

Cited by 54 publications

(37 citation statements)

References 11 publications

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“…The use of relatively small amounts of test materials makes the method potentially valuable as an alternative tool for testing powder dustiness. The ranking of levels of airborne particles generated by our system for some common materials was similar to those observed in existing aerosolization systems 19 , such as the rotating drum 15,17 , continuous drop 23 , and vortex shaker methods 24 . Furthermore, the adjustable energy input (air flow rate) can also be used for studying the stability of nanoparticle powder agglomerates.…”

Section: Representative Resultssupporting

confidence: 69%

“…Among them, two standard procedures are the established reference methods 13 for testing powder dustiness, which is defined as the tendency of a powder, subjected to a given energy input, to release airborne particles. The first method uses a rotating drum as the medium for energy input and the aerosolization of powder particles 14,15 . The second method drops a powder at a constant rate through a vertical cylinder and aerosolizes the powder particles by means of an ascending air flow 16 .…”

Section: Introductionmentioning

confidence: 99%

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A System to Create Stable Nanoparticle Aerosols from Nanopowders

Ding

Riediker

2016

JoVE

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Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring minimal amounts of test materials (min. 200 mg), for studying powder aerosolization behavior and aerosol properties. The aerosolization procedure follows the concept of the fluidized-bed process, but occurs in the modified volume of a V-shaped aerosol generator. The airborne particle number concentration is adjustable by controlling the air flow rate. The system supplied stable aerosol generation rates and particle size distributions over long periods (0.5-2 hr and possibly longer), which are important, for example, to study aerosol behavior, but also for toxicological studies. Strict adherence to the operating procedures during the aerosolization experiments ensures the generation of reproducible test results. The critical steps in the standard protocol are the preparation of the material and setup, and the aerosolization operations themselves. The system can be used for experiments requiring stable aerosol concentrations and may also be an alternative method for testing dustiness. The controlled aerosolization made possible with this setup occurs using energy inputs (may be characterized by aerosolization air velocity) that are within the ranges commonly found in occupational environments where nanomaterial powders are handled. This setup and its operating protocol are thus helpful for human exposure and risk assessment.

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Section: Representative Resultssupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

A System to Create Stable Nanoparticle Aerosols from Nanopowders

Ding

Riediker

2016

JoVE

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“…These particles could be the unconsolidated agglomeration aggregated by several primary nanoparticles, which is also called soft agglomerates or loose agglomerates in material field. Similar agglomeration cases of aerosol nanoparticles were noticed by Tsai et al (2009Tsai et al ( , 2011 at different workplace. These kinds of agglomeration particles can be de-aggregated by external forces.…”

Section: Number Concentration Distributions Of Nanoparticlessupporting

confidence: 80%

“…As an efficient sampler for aerosol nanoparticles, cascade impactor was widely used and researched in recent years (Tsai et al, 2009;Furuuchi et al, 2010). Cascade impactor uses the principle of inertial separation to size segregate particle samples from a particle laden gas stream.…”

Section: Experimental Methodsmentioning

confidence: 99%

Distribution Characteristics of nano-TiO2 Aerosol in the Workplace

Yang

Chen

et al. 2011

Aerosol Air Qual. Res.

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In this study, the distribution characteristics of nano-TiO 2 aerosol have been studied to get insight of the suspension, agglomeration and depositing performances of aerosol nanoparticles in the workplace. The number concentration and mass concentration of the aerosols have been characterized by using a wide-range particle spectrometer and cascade impactor samplers, respectively. Water based wet aerosol samplers, as well as its corresponding analysis approaches based on ultraviolet spectrometry, have also been developed to investigate the mass concentration and present an efficient sampling performance with the quite shorter sampling time than that by cascade impactors. To get a comparison of the test results with each other, sampling points have been set at the heights of breathing zone (1.0, 1.5 and 2.0 m) and at the distances of 1 to 5 m away from the discharge port of the assembly line. It is found that all the number concentration curves exhibit two peaks at the ranges of 10-200 nm and 500-900 nm. The aerosol particles with distance of 3 m exhibit the highest number concentration at all the diameter range except for the diameter less than 20 nm. While, aerosol at the distance of 5 m presents the highest number concentration, up to 18000 particles per cm 3 , in the diameter less than 20 nm. It is attributed to the spray forces of the discharge port and the suspending and depositing of aerosol nanoparticles in the air. The mass concentration and particle weight percentage at different diameter tested by cascade impactor show a strong dependence on the number concentration, which is well consistent with the results obtained by wet method.

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“…Particle numbersize-distributions can be measured using a range of different optical, aerodynamic, electrical mobility and charging techniques. Therefore, the comparability in these measurements and the reliability in conversions from number and volume concentrations metrics is still not well documented for non-spherical particles such as aggregates and agglomerates commonly observed in dustiness tests, covering a wide range of sizes from nano-to µm-size (Ibaseta and Biscans, 2007;Schneider and Jensen, 2008;Jensen et al, 2009;Tsai et al, 2009;Levin et al, 2014;Koivisto et al, 2015;Koponen et al, 2015). Even in case of direct release from an airborne synthesis processes, primary particles can already start to agglomerate or aggregate in the reactor and may further coagulate at or very near the point of release with similar result (Makela et al, 2009;Hämeri et al, 2009;Schneider et al, 2011;Koivisto et al, 2012;Koivisto et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Can We Trust Real Time Measurements of Lung Deposited Surface Area Concentrations in Dust from Powder Nanomaterials?

Levin

Witschger

Bau

et al. 2016

Aerosol Air Qual. Res.

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A comparison between various methods for real-time measurements of lung deposited surface area (LDSA) using spherical particles and powder dust with specific surface area ranging from 0.03 to 112 m 2 g -1 was conducted. LDSA concentrations measured directly using Nanoparticle Surface Area Monitor (NSAM) and Aerotrak and were compared to LDSA concentrations recalculated from size distribution measurements using Electrical Low Pressure Impactor (ELPI) and Fast Mobility Particle Sizer (FMPS). FMPS and ELPI measurements were also compared to dust surface area concentrations estimated from gravimetrical filter measurements and specific surface areas.Measurement of LDSA showed very good correlation in measurements of spherical particles (R 2 > 0.97, Ratio 1.0 to 1.04). High surface area nanomaterial powders showed a fairly reliable correlation between NSAM and Aerotrak (R 2 0.73-0.93) and a material-dependent offset in the ratios (1.04-2.8). However, the correlation and ratio were inconsistent for lower LDSA concentrations. Similar levels of correlation were observed for the NSAM and the FMPS for high surface area materials, but with the FMPS overestimating the LDSA concentration. The ELPI showed good correlation with NSAM data for high LDSA materials (R 2 0.87-0.93), but not for lower LDSA concentrations (R 2 0.50-0.72). Comparisons of respirable dust surface area from ELPI data correlated well (R 2 > 0.98) with that calculated from filter samples, but materials-specific exceptions were present.We conclude that there is currently insufficient reliability and comparability between methods in the measurement of LDSA concentrations. Further development is required to enable use of LDSA for reliable dose metric and regulatory enforcement of exposure.

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Dustiness test of nanopowders using a standard rotating drum with a modified sampling train

Cited by 54 publications

References 11 publications

A System to Create Stable Nanoparticle Aerosols from Nanopowders

A System to Create Stable Nanoparticle Aerosols from Nanopowders

Distribution Characteristics of nano-TiO2 Aerosol in the Workplace

Can We Trust Real Time Measurements of Lung Deposited Surface Area Concentrations in Dust from Powder Nanomaterials?

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