Table 5.
Studies focused on the particle release of ENMs by laboratory testing (column 1 indicates the different subcategorisations)
| Study | Process | Materials | Instrumentation | Metric | Results |
|---|---|---|---|---|---|
| Powders | |||||
| [53] | Rotating drum test (free fall, stirring, ...) | TiO2 (Aeroxide P25), ZnO | SMPS, APS, MOUDI | PSD (15 nm - 20 μm), NC, DI | < 10% particles < 100 nm60% particles < 1 μm |
| [65] | Rotating drum test (free fall, stirring, ...) | TiO2, SiO2, FeO(OH), Mg3Si4O10(OH)2, Al2O3 | FMPS, APS, Filtration | PSD (5.6 nm - 20 μm), NRP (0.5 μm - 20 μm), NRP (5.6 nm - 560 nm), DI | Undefined fraction of particles < 100 nm |
| [66] | Rotating drum test (free fall, stirring, ...) | Organoclay, Bentonite | FMPS, APS, Filtration | PSD (5.6 nm-20 μm), NRP (0.5 μm - 20 μm), NRP (5.6 nm - 560 nm), DI | Undefined fraction of particles < 100 nm |
| [70] | Free fall | TiO2 (G5), SiO2 (Aerosil 200) | ELPI; SEM (ELPI) | PSD(30 nm - 10 μm), MC, MC/M | Fraction of particles < 100 nm |
| [71] | Fluidized bed | TiO2 (Aeroxide P25) | SMPS (LDMA, NDMA), APS; TEM (ESP) | PSD (4 nm - 20 μm)/NCmax | 10% particles < 100 nm 70% particles < 1 μm |
| [4,72] | Vortex shaker (fluidized bed, agitation) | SWCNT, alumina powder | SMPS (LDMA, NDMA), APS | PSD (4 nm - 20 μm), NC | Fraction of particles < 100 nm, alumina powder released more NP than SWCNT |
| [73] | Vortex shaker (fluidized bed) | SWCNT, MWCNT, TiO2, ZnO | SMPS, HHCPC, APS, OPC | PSD (10 nm - 20 μm), NC (10 nm - > 1 μm)/V, NC (10 nm - > 1 μm)/M | Fraction of particles < 100 nm |
| [74] | Shaker method | MWCNT | SMPS, APS, TEM(ESP, CI) | PSD (14 nm - 20 μm), NC(dt) | Fraction of particles < 100 nm; peak at 200-300 nm |
| [75] | Fluidized bed with oscillating sieve plate | MWCNT | SMPS, SEM (TP) | PSD (< 1 μm), NC(dt) | Fraction of particles < 100 nm |
| [29] | Stirring and dispersing in orifice (leak in pressurized vessel) | TiO2, CeO2, SrCO3, TiZrAlO | SMPS | PSD (14 nm - 736 nm), fractions, relative values | Increase of the fraction of ENPs by increase of the overpressure (up to 12%) |
| Suspensions | |||||
| [38] | Weighing/transferring of powders and sonication of suspensions | fullerenes, MWCNT, CB | HHCPC, HHPC, TEM-EDX (filtration) | PSD (0,3 μm - 10 μm), NC (10 nm - 1 μm) | Suspension sonication leads to droplets with embedded ENM |
| [77] | Spraying | suspensions with and without Ag | SMPS, TEM(ESP) | PSD (10 nm - 500 nm), NC (< 100 nm), NC(< 500 nm) | High fraction of particles < 100 nm |
| Coatings | |||||
| [63] | Weak abrasion process (Taber Abraser) | PVC layer with/without ENPs (nanoclay) | SMPS, CPC | PSD (5 nm-1 μm) | |
| [64] | Weak abrasion process (Taber Abraser) | coatings with/without ENPs (ZnO) | SMPS, CPC; SEM/TEM-EDX (ESP) | PSD (16 nm - 626 nm), NC (> 6 nm), wear mass | Very low concentrations, ENPs still embedded |
| [81] | UV light, wind erosion, scrabing | coatings with TiO2 | SMPS | PSD (15 nm - 661 nm), NC (15 nm - 661 nm) | Comparison with non-doped samples is missing |
| [54] | Shaving (razor blade) | CNT | FMPS, HHCPC, SEM & TEM - EDX (TP) | NC (10 nm -1 μm), PSD (5.6 nm-560 nm) | No significant change in concentration; no free CNTs were observed |
| [7,8] | Sanding process (orbital sander) | coatings with/without ENPs (TiO2, CB, SiO2, CaCO3) | FMPS, APS(ESP) | PSD (5.6 nm-20 μm) | General release of NP, spark particles contamination |
| [67] | Sanding process (Dremel) | coatings with/without ENPs (ZnO, Fe2O3) | FMPS, CPC, OPCSEM/TEM-EDX (ESP) | PSD (5.6 nm-20 μm), NC (< 100 nm), NRP (< 100 nm), NRP (< 10 μm), swarf mass; material, morphology | General release of NP but ENPs still embedded in the matrix |
| Composites | |||||
| [82] | UV-light; weak abrasion process (Taber Abraser); customized sanding | POM with/without CNT, PA with/without SiO2, cement with/without CNT, cement with/without CSH | SMPS, UNPA, SEM, AUC, XPS, SIMS | PSD (14 nm-820 nm), Morphologie, material | No free SiO2-particles or CNTs detected |
| [42] | Dry and wet cutting (band-saw; rotatory cutting wheel) | composites with and without CNT | FMPS, APS, HHCPC, DT, SEM/TEM-EDX (ESP, TP) | PSD (5.6 nm-20 μm), NC (5.6 nm - 560 nm), NC (0.5 μm - 20 μm) MC, material, morphology |
No free CNTs observed |
| [69] | Dry and wet solid core drilling | Composites with and without CNT | FMPS, APS, HHCPC, DT, DC, SEM/TEM-EDX (ESP, TP) WRASS+ICP-MS | PSD (5.6 nm-20 μm), NC, MC (< 35 μm), SA; material; morphology | Smoke generation, free CNT clusters observed |