Particles Emission from an Industrial Spray Coating Process Using Nano-Materials.

Benedetta Del Secco,Franco Belosi,Fabrizio Ravegnani,Sara Trabucco,Antti Joonas Koivisto,Anna Luisa Costa,Gianni Bartolini,Magda Blosi,Marko Altin,Ilaria Zanoni,Simona Ortelli

doi:10.3390/nano12030313

Abstract

Industrial spray coating processes are known to produce excellent coatings on large surfaces and are thus often used for in-line production. However, they could be one of the most critical sources of worker exposure to ultrafine particles (UFPs). A monitoring campaign at the Witek s.r.l. (Florence, Italy) was deployed to characterize the release of TiO2 NPs doped with nitrogen (TiO2-N) and Ag capped with hydroxyethyl cellulose (AgHEC) during automatic industrial spray-coating of polymethyl methacrylate (PMMA) and polyester. Aerosol particles were characterized inside the spray chamber at near field (NF) and far field (FF) locations using on-line and off-line instruments. Results showed that TiO2-N suspension produced higher particle number concentrations than AgHEC in the size range 0.3–1 µm (on average 1.9 102 p/cm3 and 2.5 101 p/cm3, respectively) after background removing. At FF, especially at worst case scenario (4 nozzles, 800 mL/min flow rate) for TiO2-N, the spray spikes were correlated with NF, with an observed time lag of 1 minute corresponding to a diffusion speed of 0.1 m/s. The averaged ratio between particles mass concentrations in the NF position and inside the spray chamber was 1.7% and 1.5% for TiO2-N and for AgHEC suspensions, respectively. The released particles’ number concentration of TiO2-N in the size particles range 0.3–1 µm was comparable for both PMMA and polyester substrates, about 1.5 and 1.6 102 p/cm3. In the size range 0.01–30 µm, the aerosol number concentration at NF for both suspensions was lower than the nano reference values (NRVs) of 16·103 p/cm-3.

Highlights

Introduction published maps and institutional affilIndustrial processes are increasingly focused on nanotechnologies and engineered nanomaterials (NMs)
Nanotechnology provides enormous benefits, there is growing alarm about the potential health hazard [1] and possible environment damage associated with exposure to NMs, especially ultrafine particles (UFPs) of less than about 0.1 μm [2], given their significantly higher inflammatory potential than fine particles (FPs; over 100 nm) [3]
The biological activity of UFP is due to their huge surface area [4], which induces severe respiratory symptoms leading to decreased lung function and exacerbation of asthma [5,6,7]

Summary

Introduction

Industrial processes are increasingly focused on nanotechnologies and engineered nanomaterials (NMs). Nanotechnology provides enormous benefits, there is growing alarm about the potential health hazard ( for workers) [1] and possible environment damage associated with exposure to NMs, especially ultrafine particles (UFPs) of less than about 0.1 μm [2], given their significantly higher inflammatory potential than fine particles (FPs; over 100 nm) [3]. Spray-coating is a well-known industrial technique consisting of depositing suspensions of various nanoparticles (NPs) to coat a wide variety of different shaped materials [8,9]. Atomized droplets containing NPs are deposited on the surface, leaving a nanostructured coating once the liquid solvent has evaporated.

Methods

Results

Conclusion