Superparamagnetic iron oxides nanoparticles from municipal solid waste incinerators

During their production, management, and landfilling, bottom (BA) and fly (FA) ashes from municipal solid waste incineration may liberate Fe-bearing, ultrafine particles and easily enter different environmental sinks of the biosphere. We aim to explore a collection of BA and FA samples from Italian incinerators to probe magnetic mineralogy and the fraction of harmful superparamagnetic (SP) nanoparticles (d < 30 nm). X-ray diffraction, electron microscopy observation, temperature-and frequency-dependent magnetometry, and Mossbauer analysis are performed. The integration of information fromour rockmagnetic and non-magnetic techniques leads us to conclude that the dominant magnetic carrier in our samples is magnetite and its intermediate/impure forms, while sulphides (i.e., monoclinic pyrrhotite) are important ancillary magnetic phases. The SP fraction fluxing from the BA and FA outputs of a single incinerator is detected and estimated in 10(3) tons/year. This work stresses the need to calibrate the current technologies towards a safermanagement of combustion ashes and certainly to inform the environmental impact assessment by using a combination of different methods. (C) 2017 Elsevier B.V. All rights reserved.