Neeraj Shandilya

Emission of titanium dioxide nanoparticles from building materials to the environment by wear and weather.

In the present work, we investigate the effect of weathering duration on a commercial photocatalytic nanocoating on the basis of its nanoparticle emission tendency into two media, air and water. It is found that increased weathering duration results in stepwise structural deterioration of the nanocoating, which in turn decreases the nanocoating life, changes the nanocoating removal mechanism, and increases the particle emission concentration. Emission of free TiO2 nanoparticles is found to be weathering duration dependent. Three quantities are introduced: emission transition pace (ETP), stable emission level (SEL), and stable emission duration (SED). By linear extrapolation of these quantities from short weathering durations, complete failure of the nanocoatings can be predicted and, moreover, the potential increase of nanoparticles release into the air.

A review on the study of the generation of (nano)particles aerosols during the mechanical solicitation of materials

This paper focuses on presenting the forefront of the interdisciplinary studies conceived towards the generation of the wear particles aerosol when materials are subjected tomechanical stresses. Various wear mechanisms and instrumentation involved during stress application and aerosolization of wear particles, as well as particles characterization, measurement, and modeling techniques are presented through the investigation of a series of contextual works which are emphasized on the identification of these aspects. The review is motivated from the fact that understanding mechanisms involved in wear-induced particle generation, both at nanoand at microscale, is important for many applications that involve surfaces sliding over each other due to various potential health aspects. An attempt has been made to explain how the information based on this broad spectrum of subjects discovered in this contribution can be used and improved in order to produce a more resilient, rational, and versatile knowledge base which has been found lacking in the present literature during its survey. The area of study is highly multidisciplinary since it involves aerosol, particle, and material sciences.

Evaluation of the particle aerosolization from n-TiO 2 photocatalytic nanocoatings under abrasion

A parametric study on the release of titanium dioxide (TiO2) nanoparticles from two commercial photocatalytic nanocoatings is carried out. For this, abrasion tests are performed on them. The formed aerosols are characterized by their number concentration, particle size distribution, individual particle shape, size, and chemical composition. The two nanocoatings appear to exhibit contrastingly opposite behavior with respect to the number concentration of the released particles. Having irregular shapes, the released particles are found to have unimodal size distributions with 1.5-3.5% (in mass) of Ti content. However, no free nanoparticles of TiO2 were found. Distinct phases during the particle number concentration evolution with time are also discussed and evaluated. Two quantities--(ΔC/Δt)I and TII--are identified as the important indicators to qualitatively measure the resistance strength and hence the concentration of the released particles from a nanocoating during stress application.

Examples and Case Studies

Release of nanomaterials may occur during any stage of the life-cycle and can eventually lead to exposure to humans, the environment or products. Due to the large number of combinations of release processes and nanomaterials, release scenarios can currently only be tested on a case-by-case basis. This chapter presents five case studies on nanomaterial release under different conditions. While two of the case studies investigate the potential release under well-defined laboratory conditions in order to obtain a clearer picture on the release processes, the other three studies measure the potential release in real workplaces. By combining these two approaches, it is possible to gather more information on release of and exposure to nanomaterials to eventually group the different release processes and scenarios, which will significantly simplify the investigations.

Exposure assessment based recommendations to improve nanosafety at nanoliposome production sites

The NANOFOL concept aims at creating nanodevices containing a drug for inflammatory disorder treatment. This paper provides recommendations for nanosafety based on a measurement campaign which aimed at identifying exposure risks with respect to two specific phases of the products lifecycle, that is, production of the device and its waste management. The nanoparticles presence both in air and in liquid phase was studied. While no emissions were detected during the production period, many recommendations have been made, particularly regarding the nanowaste treatment, based on nanosafety guidelines.