Study of TiO₂ nanoparticle generation for follow-up inhalation experiments with laboratory animals

Figures & data

Figure 1. The scheme of the apparatus: (1) deoxygenator, (2) dryer, (CV) control valve, (D) diluter, (F) filter, (MFC) electronic mass flow controller, (N) aerosol neutralizer Am²⁴¹, (P) pressure reducing valve, (S) saturator, (SF) sampling filter, and (VP) vacuum pump.

Figure 2. The dependence of N_t, GMD, S_t, M_t, and number, mass and surface particle size distributions on time and experimental conditions (T_R, Q_R, P_TTIP, c_O) during 3rd experimental campaign. Vertical gray bars highlight sampling periods, F denotes Ag filter, FC cellulose filter, and FQ quartz filter.

Figure 3. Stability of NPs production in the form of number, surface, and mass particle size distributions during 12 h long steady-state period, T_R = 700°C, Q_R = 1400 cm³/min, P_TTIP = 1.59 Pa, c_O = 13.5 vol. %, 3rd experimental campaign.

Figure 4. A development of the particle size distribution during start-up period, 3rd experimental campaign, T_R = 700°C, Q_R = 1200 cm³/min, P_TTIP = 2.14 Pa, c_O = 12 vol. %.

Table 1. Morphological properties and SAED characteristics of NPs synthesized at various experimental conditions.

Sample	TR [°C]	QR [cm^3/min]	cO [vol. %]	PTTIP [Pa]	Max. size^a [nm]	Typical size^a^b [nm]	SAED [rings]
Ti33G	500	1200	12.25	1.99	22–30	6–11	4
Ti20G	600	1200	12.25	1.85	26–34	9–15	8
Ti10G	750	1200	12.25	2.47	20–28	8–12	8
Ti15G	800	1200	12.25	2.14	18–24	8–12	7
Ti18G	800	1200	0	1.85	22–30	9–13	10
Ti23G	900	1200	12.25	1.85	24–40	12–20	11
Ti25G	900	1200	0	1.85	24–48	12–20	11

T_R, reactor temperature;

Q_R, reactor flow rate;

c_O, oxygen concentration;

P_TTIP, TTIP vapor pressure in the reactor.

^a Estimated values from TEM images;

^b size with the highest frequency of occurrence.

Figure 5. TEM images and electron diffraction patterns of the samples of NPs synthesized at 500 (Ti33G) and 900°C (Ti23G), respectively.

Figure 6. TEM images and electron diffraction patterns of the samples of NPs synthesized at 800°C by pyrolysis (Ti18G) and oxidation (Ti15G), respectively.

Figure 7. XRD pattern and SEM image (inset) of the sample Ti19F, T_R = 600°C, Q_R = 1200 cm³/min, P_TTIP = 1.9 Pa, c_O = 12 vol %, A denotes anatase, C chlorargyrire, and S silver.

Figure 8. XRD pattern and SEM image (inset) of the sample Ti24F, T_R = 900°C, Q_R = 1200 cm³/min, P_TTIP = 1.9 Pa, c_O = 0, A denotes anatase, C chlorargyrire, R rutile, and S silver.