Particle emission characterization when incinerating nanowastes using a lab scale tubular furnace operating at 1100°C

Abstract : Nanotechnology is said to be the industry of the 21st century. The production of nanoproducts keeps growing at a rapid pace. Consequently, the need to anticipate how to deal with these products at each step of their life cycle is more and more necessary. Nanowaste management including product incineration is to be investigated to assess the impact it could have both on human health and the environment. The growing number of registrations of nanoscale substances (R-Nano in France) clearly demonstrates that the amount of nanowaste to be processed in waste treatment plants will increase in years to come. Though to date French and European regulations relative to nanowaste management do not exist, recommendations may at least be delivered to minimize possible impact on the environment and human health. Data on nanowaste incineration are still scarce. This motivates to better understand the phenomena at stake. Little is known yet about nanowaste incineration and the ensuing fate of nanoparticles. In addition, literature is scarce. In this context, the Nanowet project supported by the ADEME agency was set up to complement the existing studies. It focuses on the treatment of halogenand sulfur- containing nanowaste by elevated temperature incineration (1100°C). The objective is threefold, namely to assess the influence of (i) high temperature on the whole process (ii) the effect of the presence of acid gases in the fumes on particle emission and (iii) the effect of the wet scrubber technology installed in the waste treatment plant on nanoparticle capture efficiency. Three polymer wastes were selected and characterized for this project: two of these wastes contained nanofillers (silica and titanium dioxide) in addition with sulfur and chlorine. A lab scale horizontal tubular furnace operating with a temperature of 1100°C was utilized at INERIS nanosafety laboratory for the Nanowet experiments. Criteria relative to combustion requirements when incinerating products were carefully checked. Four series of experiments were carried out. The first three implied the incineration of each waste one after the other. The last series involved the incineration of a mix of the three wastes. It should be noted that at least four incineration experiments were carried out for each series. Eventually, the obtained results make it possible determining the fate of the nanoparticles and the impact of the mix of the three wastes on nanoparticle release.