Dustiness and Deagglomeration Testing: Interlaboratory Comparison of Systems for Nanoparticle Powders

Figures & data

TABLE 1 Physical and chemical properties of the tested materials

Name	Titanium dioxide (NM103)	Titanium dioxide (NM104)
Composition	89% TiO2, 6.2% Al2O3	89.8% TiO2, 6.2% Al2O3
Primary particle size (XRD), nm	20	20
Surface modification	Hydrophobic (PHO)	Hydrophilic (PHI)
Specific area, m^2/g	60	60
Crystal structure	Rutile	Rutile
Moisture content	1.61%	2.02%

* Information from the manufacturer.

FIG. 1. Aerosolization systems tested: (a) fluidization funnel; (b) magnetic stirrer; (c) air jet aerosolizer; (d) continuous drop.

TABLE 2 General comparison of test setups

System	Material quantity	Flow rate, L/min	Relative humidity	Aerosolization mechanism	Relative velocity (energy level), m/s
Funnel	250 ± 10 mg	1.5–2	2 ± 0.2%	Blowing	1.32–2.20 (medium)
Stirrer	20 cm^3 (5–8 g)	2	<2%	Mechanical stirring	0–1.96 (low-medium)
Air jet	500 ± 10 mg	5	26 ± 2%	Blowing	14 (high)
Drop	2.8 g/min	53	50%	Air friction	0.003–0.88 (low)

FIG. 2. Comparison of total particle number (34–965 nm) (left) and mode diameter (right).

FIG. 3. Influence of aerosolization flow velocity on mode diameter of generated aerosols (fitted curves are added to show the general patterns; white dot on left graph represents secondary mode diameter for the drop method).

FIG. 4. Drag force–particle size relationship for the various relative velocities in the tests.

  FIG. 5. Comparison of full particle number size distributions for the different systems.