Nanomaterial release characteristics in a single-walled carbon nanotube manufacturing workplace

Ji, Jun Ho; Kim, Jong Bum; Lee, Gwangjae

doi:10.1007/s11051-015-2884-x

Cited by 10 publications

(5 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…• Class I: size-resolved, time-resolved instruments whose particle detection capability is based on optical or electrical mobility, such as the Scanning Mobility Particle Sizer (SMPS) [30,31], Fast Mobility Particle Sizer (FMPS) [32][33][34], Optical Particle Counter (OPC) [35][36][37] and Electrical Low-Pressure Impactor (ELPI) [38,39]. • Class II: size-integrated, time-resolved instruments, such as the Condensation Particle Counter (CPC) [30,36] and Nanoparticle Surface Area Monitor (NSAM) [40,41].…”

Section: Instruments and Techniquesmentioning

confidence: 99%

Occupational Release of Engineered Nanoparticles: A Review

Faghihi

Morawska

2015

The Handbook of Environmental Chemistry

View full text Add to dashboard Cite

Characterising the release of different types of engineered nanoparticles (ENPs) from various processes is of critical importance for the assessment of human exposure, as well as understanding the possible health effects of these particles. Therefore, the main aim of this chapter is to present a comprehensive review of studies which report on the release of airborne ENPs in different nanotechnology workplaces. The chapter will cover topics of relevance to the occupational characterisation of ENP emissions, ranging from the identification of different particle release sources and scenarios to measurement methods and working towards a more uniform approach to characterisation. Furthermore, a brief review of ENP exposure control strategies, together with the application of mathematical modelling as an effective tool for the characterisation of emissions at nanotechnology workplaces, is included.

show abstract

Section: Instruments and Techniquesmentioning

confidence: 99%

Occupational Release of Engineered Nanoparticles: A Review

Faghihi

Morawska

2015

The Handbook of Environmental Chemistry

View full text Add to dashboard Cite

show abstract

“…With aethalometers, it is possible to get time-resolved data (approximately in the range of minutes, depending on concentration) showing, for example peak exposures. Previously, eBC measurements have been used in workplaces to detect CNTs in the emission zone (EZ) or background zone (BGZ) ( Han et al , 2008 ; Lee et al , 2010 ; Hashimoto et al , 2013 ; Ji et al, 2013 , 2015 ; Kim et al , 2016 ). Thus, eBC may be used as a proxy for EC; however, the mass concentration of CNTs may be underestimated, as CNT materials may have different optical properties compared with other common EC materials such as diesel soot ( Hashimoto et al , 2013 ).…”

Section: Introductionmentioning

confidence: 99%

Real-Time Emission and Exposure Measurements of Multi-walled Carbon Nanotubes during Production, Power Sawing, and Testing of Epoxy-Based Nanocomposites

Hedmer

Lovén

Martinsson

et al. 2022

Annals of Work Exposures and Health

View full text Add to dashboard Cite

Objectives The use of manufactured nanomaterials is increasing globally. Although multi-walled carbon nanotubes (CNTs) are used in a wide range of applications, only limited data are available on emissions and exposures during CNT composite production. No exposure data using portable aethalometers in the personal breathing zone (PBZ) to monitor occupational exposure to CNTs have yet been published. The aim of this study was to characterize emissions of and exposures to CNTs during CNT composite production, sawing, and shear testing. We also investigated whether real-time aethalometer measurements of equivalent black carbon (eBC) could be used as a proxy filter sampling of elemental carbon (EC). The presence of CNTs as surface contamination in the production facility was monitored since this could contribute to airborne exposure. Methods During CNT composite production in an industrial setting including both chemical and manufacturing laboratories, different work tasks (WTs) were studied with a combination of direct-reading instruments (aethalometer, aerodynamic particle sizer, condensation particle counter) and filter-based methods. Measurements were performed to monitor concentrations in the emission zone (EZ), PBZ, and background zone. The filter samples were analysed for EC and fibre concentration of CNTs using scanning electron microscopy (SEM). Additionally, surfaces in the facility were tape sampled for monitoring of CNT contamination, and analysed with SEM. Results Clear eBC peaks were observed in the PBZ during several WTs, most clearly during open handling of CNT powder. Power sawing emitted the highest particle number concentration in the EZ of both nanoparticles and coarse particles, but no individual airborne CNTs, agglomerates, or aggregates were detected. Airborne CNTs were identified, for example, in a filter sample collected in the PBZ of a worker during mixing of CNT epoxy. The airborne CNT particles were large agglomerates which looked like porous balls in the SEM images. Significant EC exposures were found in the inhalable fraction while all respirable fractions of EC were below detection. The highest inhalable EC concentrations were detected during the composite production. No significant correlation was found between inhalable EC and eBC, most likely due to losses of large EC containing particles in the sampling lines and inside the eBC monitor. In total, 39 tape samples were collected. Surface contamination of CNTs was detected on eight surfaces in the chemical and manufacturing laboratories, mainly in the near-field zone. Elongated CNT-like features were detected in the sawdust after sawing of CNT composite. Conclusions Characterization of a workplace producing CNT composite showed that open handling of the CNT powder during weighing and mixing of CNT powder material generated the highest particle emissions and exposures. The portable direct-reading aethalometer provided time-resolved eBC exposure data with complementary information to time-integrated EC filter samples by linking peak exposures to specific WTs. Based on the results it was not possible to conclude that eBC is a good proxy of EC. Surface contamination of CNTs was detected on several surfaces in the near-field zone in the facility. This contamination could potentially be resuspended into the workplace air, and may cause secondary inhalation exposure.

show abstract

“…Many of the studies which have been conducted were at research facilities where CNTs were produced (Maynard et al, 2004;Bello et al, 2008a;Tsai et al, 2009;Methner et al, 2010;Ogura et al, 2010) and handled ( Johnson et al, 2010;Methner et al, 2010;R'mili et al, 2010) and where advanced composites containing CNTs were produced (Cena and Peters, 2011;Fleury et al, 2013) or machined (Bello et al, 2008b). Additional studies have been conducted at industrial sites where CNTs or products utilizing CNTs were manufactured (Han et al, 2008;Lee et al, 2010Lee et al, , 2014Lee et al, , 2015Dahm et al, 2012Dahm et al, , 2015Wang et al, 2011;Methner et al, 2012;Takaya et al, 2012;Fonseca et al, 2014;Hedmer et al, 2014;Heitbrink et al, 2015;Ji et al, 2015). Only two studies have employed the recommended sampling and analytical method for quantifying the CNT REL.…”

Section: Introductionmentioning

confidence: 99%

Aerosol Emission Monitoring and Assessment of Potential Exposure to Multi-walled Carbon Nanotubes in the Manufacture of Polymer Nanocomposites

Thompson

Chen

Wang

et al. 2015

ANNHYG

View full text Add to dashboard Cite

Recent animal studies have shown that carbon nanotubes (CNTs) may pose a significant health risk to those exposed in the workplace. To further understand this potential risk, effort must be taken to measure the occupational exposure to CNTs. Results from an assessment of potential exposure to multi-walled carbon nanotubes (MWCNTs) conducted at an industrial facility where polymer nanocomposites were manufactured by an extrusion process are presented. Exposure to MWCNTs was quantified by the thermal-optical analysis for elemental carbon (EC) of respirable dust collected by personal sampling. All personal respirable samples collected (n = 8) had estimated 8-h time weighted average (TWA) EC concentrations below the limit of detection for the analysis which was about one-half of the recommended exposure limit for CNTs, 1 µg EC/m 3 as an 8-h TWA respirable mass concentration. Potential exposure sources were identified and characterized by direct-reading instruments and area sampling. Area samples analyzed for EC yielded quantifiable mass concentrations inside an enclosure where unbound MWCNTs were handled and near a pelletizer where nanocomposite was cut, while those analyzed by electron microscopy detected the presence of MWCNTs at six locations throughout the facility. Through size selective area sampling it was identified that the airborne MWCNTs present in the workplace were in the form of large agglomerates. This was confirmed by electron microscopy where most of the MWCNT structures observed were in the form of micrometer-sized ropey agglomerates. However, a small fraction of single, free MWCNTs was also observed. It was found that the high number concentrations of nanoparticles, ~200 000 particles/ cm 3 , present in the manufacturing facility were likely attributable to polymer fumes produced in the extrusion process.

show abstract

Nanomaterial release characteristics in a single-walled carbon nanotube manufacturing workplace

Cited by 10 publications

References 21 publications

Occupational Release of Engineered Nanoparticles: A Review

Occupational Release of Engineered Nanoparticles: A Review

Real-Time Emission and Exposure Measurements of Multi-walled Carbon Nanotubes during Production, Power Sawing, and Testing of Epoxy-Based Nanocomposites

Aerosol Emission Monitoring and Assessment of Potential Exposure to Multi-walled Carbon Nanotubes in the Manufacture of Polymer Nanocomposites

Contact Info

Product

Resources

About