Plastics in WEEE

As part of the CIRCOPLAST project, a literature review was conducted to identify the materials present in Waste Electrical and Electronic Equipment (WEEE) and support recycling decisions.

WEEE consists mainly of ferrous and non-ferrous metals, glass, and plastics, the latter accounting for about 30% of the total weight of WEEE produced annually [Goosey, E. et al.]. Different types of electrical and electronic equipment (EEE) contain a variety of plastics, among which the most common are acrylonitrile butadiene styrene (ABS), polypropylene (PP), high-impact polystyrene (HIPS), and polycarbonate/ABS blends. Other polymers such as polyurethane (PU), polyethylene (PE), and polyvinyl chloride (PVC) are also present. The composition of an actual batch of WEEE analyzed by FTIR-ATR is shown in Figure 1 [Gripon et al.]. However, the complexity of plastic mixtures in WEEE poses a major challenge for recycling. In the absence of efficient sorting technologies, about 40–50% of plastics contained in WEEE are not properly recycled [Haarman, A. et al.].

Figure 1. Composition of an actual WEEE batch determined by FTIR-ATR [Gripon et al.]

Another critical issue is the presence of hazardous components, notably heavy metals (lead, cadmium, mercury) and flame retardants (FR), required to meet fire safety standards. The most widespread flame retardants are halogenated, mainly brominated (BFR) or chlorinated, often used with antimony trioxide (Sb₂O₃) as a synergist [Alassali, A. et al.]. In 2018, BFRs accounted for about 55% of the global flame retardant market, while chlorinated FRs represented only 1% [CERESANA].

Among the BFRs found in WEEE, the most well-known are polybromodiphenyl ethers (PBDE), tetrabromobisphenol A (TBBPA), and hexabromocyclododecane (HBCDD) [Freegard, K. et al.]. Although they ensure compliance with flammability standards, these compounds are persistent, bioaccumulative, and toxic, and remain present at high concentrations in WEEE. According to the International Bromine Council (2023), the average level of BFRs in mixed WEEE plastics is 3.5%, including 3.3% for unrestricted BFRs and 0.2% for PBDEs, as shown in Figure 2.

Figure 2. Average BFR levels in mixed WEEE plastics [Brominated Flame Retardants and the Circular Economy of WEEE Plastics, State of Play, The International Bromine Council, 2023].

TBBPA, used notably in epoxy and polycarbonate resins, ABS and HIPS resins, as well as in certain textiles, represents about 60% of the global BFR market [Zuiderveen, E.A.R. et al.]. It is classified under the GHS as highly toxic to aquatic life with long-lasting effects (H410). The European Union amended Directive 2008/98/EC in 2017 to classify WEEE containing more than 2500 mg/kg of TBBPA as hazardous waste, limiting its recycling [Oko-Institut e.V.]. HBCDD, meanwhile, is mainly used in polystyrene foams, as well as in various construction materials, adhesives, and coatings [Charitopoulou, M.A. et al.]. Along with TBBPA, it is listed among persistent organic pollutants (POPs) due to its toxicity and environmental persistence. In response to these concerns, new brominated flame retardants (NBFRs), such as decabromodiphenylethane (DBDPE), are being introduced to the market, although their long-term impact remains to be assessed [Xiong, P. et al.].

This literature review provides a solid foundation for selecting materials on which to focus recycling and innovation efforts, taking into account technical, environmental, and health aspects.