Alessandra Marra

Bioleaching of metals from WEEE shredding dust

A bioleaching process developed in two separate steps was investigated for the recovery of base metals, precious metals and rare earth elements from dusts generated by Waste Electrical and Electronic Equipment (WEEE) shredding. In the first step, base metals were almost completely leached from the dust in 8 days by Acidithiobacillus thiooxidans (DSM 9463) that lowered the pH of the leaching solution from 3.5 to 1.0. During this step, cerium, europium and neodymium were mobilized at high percentages (>99%), whereas lanthanum and yttrium reached an extraction yield of 80%. In the second step, the cyanide producing Pseudomonas putida WSC361 mobilized 48% of gold within 3xa0h from the A.xa0thiooxidans leached shredding dust. This work demonstrated the potential application of biohydrometallurgy for resource recovery from WEEE shredding dust, destined to landfill disposal, and its effectiveness in the extraction of valuable substances, including elements at high supply risk as rare earths.

Biotechnological strategies for the recovery of valuable and critical raw materials from waste electrical and electronic equipment (WEEE) – A review

Critical raw materials (CRMs) are essential in the development of novel high-tech applications. They are essential in sustainable materials and green technologies, including renewable energy, emissionfree electric vehicles and energy-efficient lighting. However, the sustainable supply of CRMs is a major concern. Recycling end-of-life devices is an integral element of the CRMs supply policy of many countries. Waste electrical and electronic equipment (WEEE) is an important secondary source of CRMs. Currently, pyrometallurgical processes are used to recycle metals from WEEE. These processes are deemed imperfect, energy-intensive and non-selective towards CRMs. Biotechnologies are a promising alternative to the current industrial best available technologies (BAT). In this review, we present the current frontiers in CRMs recovery from WEEE using biotechnology, the biochemical fundamentals of these bio-based technologies and discuss recent research and development (R&D) activities. These technologies encompass biologically induced leaching (bioleaching) from various matrices,biomass-induced sorption (biosorption), and bioelectrochemical systems (BES).

A methodology hazard-based for the mitigation of the radon risk in the urban planning

A type of significant impact is the risk from radon gas in indoor settings, which is not been yet listed among the types of risk canonically considered in planning, such as the hydrogeological, seismic and volcanic risk, by fires and relevant accident risk (Castelluccio et al, 2012). The radon is a radioactive gas, that was classified since 1988 by the WHO as a carcinogen of the Group I (IARC-WHO, 1988), i.e. an oncogenic factor proved on humans. The European Union, transposing these indications, requires to the Member States, through the EU Directive, 59, 2013, the identification of areas particularly prone to radon, known as radon prone areas in the literature. However, currently there is still no international standard for the mapping of these areas. Moreover, this Directive defers the mitigation of the phenomenon to the building regulations. This research shows a methodology to build the risk maps of radon at the urban scale, as you can regulate and specify mitigation actions only at this spatial level.