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Comparison of nanoparticle exposures between fumed and sol-gel nano-silica manufacturing facilities.

Oh S, Kim B, Kim H - Ind Health (2014)

Bottom Line: Due to the high-temperature formation process, the particles exhibited a sintering coagulation.In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm(3) with an assumption of 1,000,000 particles/cm(3) when the upper limit is exceeded (5% of total measure).The particles from SS process had a spherical-shaped morphology with GMD measured by SMPS of 94 nm.

View Article: PubMed Central - PubMed

Affiliation: Ministry of Employment and Labor, Republic of Korea.

ABSTRACT
Silica nanoparticles (SNPs) are widely used all around the world and it is necessary to evaluate appropriate risk management measures. An initial step in this process is to assess worker exposures in their current situation. The objective of this study was to compare concentrations and morphologic characteristics of fumed (FS) and sol-gel silica nanoparticles (SS) in two manufacturing facilities. The number concentration (NC) and particle size were measured by a real-time instrument. Airborne nanoparticles were subsequently analyzed using a TEM/EDS. SNPs were discharged into the air only during the packing process, which was the last manufacturing step in both the manufacturing facilities studied. In the FS packing process, the geometric mean (GM) NC in the personal samples was 57,000 particles/cm(3). The geometric mean diameter (GMD) measured by the SMPS was 64 nm. Due to the high-temperature formation process, the particles exhibited a sintering coagulation. In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm(3) with an assumption of 1,000,000 particles/cm(3) when the upper limit is exceeded (5% of total measure). The particles from SS process had a spherical-shaped morphology with GMD measured by SMPS of 94 nm.

No MeSH data available.


Related in: MedlinePlus

Particle shape of silica nanoparticles collected by a TEM grid on the potableelectrostatic precipitator: (a) fumed silica, (b) sol-gel silica, (c) EDS results;The bars in (a) and (b) indicate 500 nm.
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fig_005: Particle shape of silica nanoparticles collected by a TEM grid on the potableelectrostatic precipitator: (a) fumed silica, (b) sol-gel silica, (c) EDS results;The bars in (a) and (b) indicate 500 nm.

Mentions: When packaging FS, the mean particle size distribution measured by the SMPS showed abimodal distribution, which had peaks at 40 nm and 90 nm with the concentration at the40 nm peaks being higher (Fig. 3-e). However, inthe case of high concentration (upper 5%), the concentration at the 90 nm peaks washigher. Therefore, it is considered that as the concentration increases, the coagulationbetween particles increases. Coagulation between particles was also identified by TEManalysis; the physical diameter of primary particles of FS was 12 nm, but most of themwere found to be coagulated. Sintering coagulation was observed in the primary particlesof FS, which were formed through agglomeration at high temperature (Fig. 5-aFig. 5.


Comparison of nanoparticle exposures between fumed and sol-gel nano-silica manufacturing facilities.

Oh S, Kim B, Kim H - Ind Health (2014)

Particle shape of silica nanoparticles collected by a TEM grid on the potableelectrostatic precipitator: (a) fumed silica, (b) sol-gel silica, (c) EDS results;The bars in (a) and (b) indicate 500 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4209587&req=5

fig_005: Particle shape of silica nanoparticles collected by a TEM grid on the potableelectrostatic precipitator: (a) fumed silica, (b) sol-gel silica, (c) EDS results;The bars in (a) and (b) indicate 500 nm.
Mentions: When packaging FS, the mean particle size distribution measured by the SMPS showed abimodal distribution, which had peaks at 40 nm and 90 nm with the concentration at the40 nm peaks being higher (Fig. 3-e). However, inthe case of high concentration (upper 5%), the concentration at the 90 nm peaks washigher. Therefore, it is considered that as the concentration increases, the coagulationbetween particles increases. Coagulation between particles was also identified by TEManalysis; the physical diameter of primary particles of FS was 12 nm, but most of themwere found to be coagulated. Sintering coagulation was observed in the primary particlesof FS, which were formed through agglomeration at high temperature (Fig. 5-aFig. 5.

Bottom Line: Due to the high-temperature formation process, the particles exhibited a sintering coagulation.In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm(3) with an assumption of 1,000,000 particles/cm(3) when the upper limit is exceeded (5% of total measure).The particles from SS process had a spherical-shaped morphology with GMD measured by SMPS of 94 nm.

View Article: PubMed Central - PubMed

Affiliation: Ministry of Employment and Labor, Republic of Korea.

ABSTRACT
Silica nanoparticles (SNPs) are widely used all around the world and it is necessary to evaluate appropriate risk management measures. An initial step in this process is to assess worker exposures in their current situation. The objective of this study was to compare concentrations and morphologic characteristics of fumed (FS) and sol-gel silica nanoparticles (SS) in two manufacturing facilities. The number concentration (NC) and particle size were measured by a real-time instrument. Airborne nanoparticles were subsequently analyzed using a TEM/EDS. SNPs were discharged into the air only during the packing process, which was the last manufacturing step in both the manufacturing facilities studied. In the FS packing process, the geometric mean (GM) NC in the personal samples was 57,000 particles/cm(3). The geometric mean diameter (GMD) measured by the SMPS was 64 nm. Due to the high-temperature formation process, the particles exhibited a sintering coagulation. In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm(3) with an assumption of 1,000,000 particles/cm(3) when the upper limit is exceeded (5% of total measure). The particles from SS process had a spherical-shaped morphology with GMD measured by SMPS of 94 nm.

No MeSH data available.


Related in: MedlinePlus