Skip to main content
Log in

Dustiness behaviour of loose and compacted Bentonite and organoclay powders: What is the difference in exposure risk?

  • Nanoparticles and Occupational Health
  • Published:
Journal of Nanoparticle Research Aims and scope Submit manuscript

Abstract

Single-drop and rotating drum dustiness testing was used to investigate the dustiness of loose and compacted montmorillonite (Bentonite) and an organoclay (Nanofil®5), which had been modified from montmorillonite-rich Bentonite. The dustiness was analysed based on filter measurements as well as particle size distributions, the particle generation rate, and the total number of generated particles. Particle monitoring was completed using a TSI Fast Mobility Particle Sizer (FMPS) and a TSI Aerosol Particle Sizer (APS) at 1 s resolution. Low-pressure uniaxial powder compaction of the starting materials showed a logarithmic compaction curve and samples subjected to 3.5 kg/cm2 were used for dustiness testing to evaluate the role of powder compaction, which could occur in powders from large shipments or high-volume storage facilities. The dustiness tests showed intermediate dustiness indices (1,077–2,077 mg/kg powder) in tests of Nanofil®5, Bentonite, and compacted Bentonite, while a high-level dustiness index was found for compacted Nanofil®5 (3,487 mg/kg powder). All powders produced multimodal particle size-distributions in the dust cloud with one mode around 300 nm (Bentonite) or 400 nm (Nanofil®5) as well as one (Nanofil®5) or two modes (Bentonite) with peaks between 1 and 2.5 μm. The dust release was found to occur either as a burst (loose Bentonite and Nanofil®5), constant rate (compacted Nanofil®5), or slowly increasing rate (compacted Bentonite). In rotating drum experiments, the number of particles generated in the FMPS and APS size-ranges were in general agreement with the mass-based dustiness index, but the same order was not observed in the single-drop tests. Compaction of Bentonite reduced the number of generated particles with app. 70 and 40% during single-drop and rotating drum dustiness tests, respectively. Compaction of Nanofil®5 reduced the dustiness in the single-drop test, but it was more than doubled in the rotating drum test. Physically relevant low-pressure compaction may reduce the risk of particle exposure if powders are handled in operations with few agitations such as pouring or tapping. Repeated agitation, e.g., mixing, of these compacted powders, would result in reduced (app. 20% for Bentonite) or highly increased (app. 225% for Nanofil®5) dustiness and thereby alter the exposure risk significantly.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

Similar content being viewed by others

References

  • Bohgard M, Anderberg MT, Eklund A (1994) Source characteristics of emitted aerosols in the size range 0.02 to 20 μm at pigment handling in dye manufacturing. J Aerosol Sci 25(Suppl 1):S461–S462

    Article  Google Scholar 

  • Brockel U, Wahl M, Kirsch R, Feise HJ (2006) Formation and growth of crystal bridges in bulk solids. Chem Eng Technol 29:691–695

    Article  Google Scholar 

  • Burdett GJ, Chung KYK, Mark D, Armbruster L, Breum NO (2000) Development of a method for dustiness testing. EU contract SMT4-CT96-2074. HSE report IR/L/MF/00/11. Health and Safety Laboratory, Sheffield, UK

  • Carrizosa MJ, Hermosin MC, Koskinen WC, Cornejo J (2003) Use of organosmectites to reduce leaching losses of acidic herbicides. Soil Sci Soc Am J 67:511–517

    CAS  Google Scholar 

  • CEN (1993) EN 481. Workplace atmospheres—size fraction definitions for measurements of airborne particles. European Committee for Standardization, Brussels

    Google Scholar 

  • CEN (2006) EN 15051 Workplace atmospheres–Measurement of the dustiness of bulk materials—requirements and reference test methods. European Committee for Standardization, Brussels

    Google Scholar 

  • Dai Y-Y, Juang Y-J, Wu Y-Y, Breysse PN, Hsu D-J (2006) In vivo measurement of inhalability of ultralarge aerosol particles in calm air by humans. J Aerosol Sci 37:967–973

    Article  CAS  Google Scholar 

  • Freitag F, Kleinebudde P (2003) How do roll compaction/dry granulation affect the tableting behaviour of inorganic materials? Comparison of four magnesium carbonates. EJPS 19:281–289

    Article  CAS  Google Scholar 

  • Gbureck U, Dembski S, Thull R, Barralet JE (2005) Factors influencing calcium phosphate cement shelf-life. Biomaterials 26:3691–3697

    Article  PubMed  CAS  Google Scholar 

  • Guven N (1991) On a definition of Illite Smectite mixed-layer. Clays Clay Miner 39:661–662

    Article  CAS  Google Scholar 

  • Heim A, Obraniak A, Gluba T (2005) Changes of feed bulk density during drum granulation of Bentonite. Physicochem Probl Miner Process 39:219–228

    Google Scholar 

  • Hjemsted K, Schneider T (1996) Documentation of a dustiness drum test. Ann Occup Hyg 40:627–643

    CAS  Google Scholar 

  • Kamena K (2005) Nanoclays and their emerging markets. In: Xanthos M (ed) Functional fillers for plastics. WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, pp 163–174

    Chapter  Google Scholar 

  • Konta J (1995) Clay and man: clay raw materials in the service of man. Appl Clay Sci 10:275–335

    Article  CAS  Google Scholar 

  • Kuhlbusch TAJ, Neumann S, Fissan H (2004) Number size distribution, mass concentration, and particle composition of PM1, PM2.5, and PM10 in bag filling areas of carbon black production. J Occup Environ Hyg 1:660–671

    Article  PubMed  CAS  Google Scholar 

  • Liden G (2006) Dustiness testing of materials handled at workplaces. Ann Occup Hyg 50:437–439

    Article  PubMed  Google Scholar 

  • Limbach LK, Li YC, Grass RN et al (2005) Oxide nanoparticle uptake in human lung fibroblasts: effects of particle size, agglomeration, and diffusion at low concentrations. Environ Sci Technol 39:9370–9376

    Article  PubMed  CAS  Google Scholar 

  • Maynard AD (2002) Experimental determination of ultrafine TiO2 deagglomeration in a surrogate pulmonary surfactant: preliminary results. Ann Occup Hyg 46(Supplement 1):197–202

    Google Scholar 

  • Maynard AD, Baron PA, Foley M et al (2004) Exposure to carbon nanotube material: aerosol release during the handling of unrefined single-walled carbon nanotube material. J Toxicol Environ Health A 67:87–107

    Article  PubMed  CAS  Google Scholar 

  • Nishii K, Horio M (2007) Dry granulation. In: Salman AD (ed) Handbook of powder granulation technology, Chap 6. Elsevier Science B.V., pp 289–322

  • Patel HA, Somani RS, Bajaj HC, Jasra RV (2006) Nanoclays for polymer nanocomposites, paints, inks, greases and cosmetics formulations, drug delivery vehicle and waste water treatment. Bull Mater Sci 29:133–145

    Article  CAS  Google Scholar 

  • Plinke MAE, Leith D, Boundy MG, Löffler F (1995) Dust generation from handling powders in industry. Am Ind Hyg Assoc J 56:251–257

    Google Scholar 

  • Raja PMV, Connolley J, Ganesan GP et al (2007) Impact of carbon nanotube exposure, dosage and aggregation on smooth muscle cells. Toxicol Lett 169:51–63

    Article  PubMed  CAS  Google Scholar 

  • Ray SS, Okamoto M (2003) Polymer/layered silicate nanocomposites: a review from preparation to processing. Prog Polym Sci 28:1539–1641

    Article  CAS  Google Scholar 

  • Schneider T, Jensen KA (2008) Combined single-drop and rotating drum dustiness test of fine to nanosize powders using a small drum. Ann Occup Hyg 52/1:23–34

    Google Scholar 

  • Szepvolgyi J, Mohai I, Gubicza J (2001) Atmospheric ageing of nanosized silicon nitride powders. J Mater Chem 11:859–863

    Article  CAS  Google Scholar 

  • Takano K, Horio M (2004) Particle design for dry powder inhalation via binderless powder coating by pressure swing granulation. Powder Technol 141:196–202

    Article  CAS  Google Scholar 

  • Tardos GI (2005) Wet-granulation research with application to scale-up. China Particuol 3:191–195

    Article  CAS  Google Scholar 

  • Tien YM, Wu PL, Chu CA et al (2007) The friction-free compressibility curve of Bentonite block. Phys Chem Earth Parts A/B/C 32:809–819

    Article  Google Scholar 

  • Wick P, Manser P, Limbach LK et al (2007) The degree and kind of agglomeration affect carbon nanotube cytotoxicity. Toxicol Lett 168:121–131

    Article  PubMed  CAS  Google Scholar 

  • Wieczorek M, Krysztafkiewicz A, Jesionowski T (2003) Comparative characteristics of local and foreign bentonites. Macromol Symp 194:345–350

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This study was part of the NANOPLAST project supported by The Working Environment Research Fund, Denmark. We highly appreciate assistance from technician S.H. Nielsen in conducting the experiments.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Keld Alstrup Jensen.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Jensen, K.A., Koponen, I.K., Clausen, P.A. et al. Dustiness behaviour of loose and compacted Bentonite and organoclay powders: What is the difference in exposure risk?. J Nanopart Res 11, 133–146 (2009). https://doi.org/10.1007/s11051-008-9420-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11051-008-9420-1

Keywords

Navigation