Size Distribution of TiO₂ Nanoparticles Generated by a Commercial Aerosol Generator for Different Solution Concentrations and Air Flow Rates

Abstract

Advances in scientific research in the field of nanotechnology sparked an increase in technological and industrial applications involving nanoparticles, Moreover, there was increasing concern about the control of nanoscale particles released to the atmosphere, driven by concerns over air quality and human health. In this context, this study aims to determine the size distribution of TiO2nanoparticles generated by the commercial TSI Atomizer Aerosol Generator model 3079 for different solution concentrations and air flow rates. The concentrations of the TiO2solutions used in the generator were 0.0125, 0.025 and 0.05 g.L-1, while the aerosol flow rates were 1.27, 2.55 and 3.82 L.min-1. The size distribution was measured with the TSI Scanning Mobility Particle Sizer (SMPS) equipment, which provides the number of particles per size range. The results showed that even changing the concentration of TiO2in solution, peak concentrations of nanoparticles remained in the same range between 15 to 45 nm. Moreover, it was observed that particle concentration in the gas stream decreased with increasing flow rate.

Analysis of the Collection Efficiency of Fiber Filters on the Filtration of Nano-Sized Particles from Aerosol

“…It is observed that the minimum filtration efficiency was found to be 0.77 for the 0.09 m/s (for dp=150 nm) and greater filtration efficiency was 0.95 for the 0.03 m/s (for dp =20 nm). According [8], this happened because diffusion is the dominant collection mechanism in the removal of nanosized particle and because it's moving is affected by shelling gas, causing irregular moving and collision of particles in fiber of the filter media.…”

“…The mechanisms of collection by gravity and inertia are predominant with larger particles (above 5µm) with low velocities [7]. According to [8], studies have demonstrated that the predominant mechanism of collection in the removal of nanosized particles is the diffusion, as shown by [6] and [9]. [10] shows that the global efficiency can be estimated by the sum of all the mechanisms mentioned:…”