Limits...
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

(a) paper bags are filled with fumed silica by a packing machine (b) mobile cartfor nanoparticle exposure assessment in fumed silica factory (c) pouring the sol-gelsilica powder into the injection hole of jet mil and show the mobile cart
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4209587&req=5

fig_002: (a) paper bags are filled with fumed silica by a packing machine (b) mobile cartfor nanoparticle exposure assessment in fumed silica factory (c) pouring the sol-gelsilica powder into the injection hole of jet mil and show the mobile cart

Mentions: SS are discharged in the air; while pouring the powder into the injection hole of jetmill, and transferring pulverized SS to vinyl bags. In addition, highly concentratedsilica nanoparticles may be ejected through leaks in the top and the middle sections ofthe jet mill in the early stage of pulverization (the phenomenon disappears once theoperation is stabilized after reassembly). A chemical coating is added on the surface ofSS, if necessary. Epoxy-coated silica nanoparticles, 100 nm in primary particle size, wereproduced on the day of this study. SNPs are pulverized in 12-kg batches and then packed.The operation takes 1 h to complete, and is repeated 7–8 times a day on average by anoperator wearing an electric supply-air respirator. The size of packing room is 2.5 m inwidth, 2.5 m in length, and 5 m in height without a local exhaust ventilation system. Theinvestigation was performed on December 27, 2012 (Fig.2Fig. 2.


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

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

(a) paper bags are filled with fumed silica by a packing machine (b) mobile cartfor nanoparticle exposure assessment in fumed silica factory (c) pouring the sol-gelsilica powder into the injection hole of jet mil and show the mobile cart
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig_002: (a) paper bags are filled with fumed silica by a packing machine (b) mobile cartfor nanoparticle exposure assessment in fumed silica factory (c) pouring the sol-gelsilica powder into the injection hole of jet mil and show the mobile cart
Mentions: SS are discharged in the air; while pouring the powder into the injection hole of jetmill, and transferring pulverized SS to vinyl bags. In addition, highly concentratedsilica nanoparticles may be ejected through leaks in the top and the middle sections ofthe jet mill in the early stage of pulverization (the phenomenon disappears once theoperation is stabilized after reassembly). A chemical coating is added on the surface ofSS, if necessary. Epoxy-coated silica nanoparticles, 100 nm in primary particle size, wereproduced on the day of this study. SNPs are pulverized in 12-kg batches and then packed.The operation takes 1 h to complete, and is repeated 7–8 times a day on average by anoperator wearing an electric supply-air respirator. The size of packing room is 2.5 m inwidth, 2.5 m in length, and 5 m in height without a local exhaust ventilation system. Theinvestigation was performed on December 27, 2012 (Fig.2Fig. 2.

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