Chemical and Thermochemical Recycling of Polymers from Waste Electrical and Electronic Equipment

Abstract

The production of electric and electronic equipment (EEE), including personal computers, compact disks, TV sets, refrigerators, washing machines, toasters and many other daily-life items, is one of the fastest growing areas of manufacturing industry today. The rapid development in the EEE technology combined with a short life cycle and a variety of uses, at least for most of the products, poses a significant issue as far as their disposal is concerned. This has resulted in a continuous increase of Waste Electric and Electronic Equipment (WEEE) with some representative numbers: in the EU only, 9.5 million tones have been disposed in 2008 and this is expected to increase to 12.3 million tones in 2020 [1, 2]. While there is no generally accepted definition of electronic waste in most cases electronic waste consists of electronic products that were used for data processing, telecommunications, or entertainment in private households and businesses and are now considered obsolete, broken, or unrepairable (Figure 1). Despite its common classification as a waste, disposed electronics are a considerable category of secondary resource due to their significant suitability for direct reuse and material recycling. In view of the environmental problem involved in the management of WEEE, many countries and organizations have drafted national legislation to improve the reuse, recycling and other forms of recovery of such wastes so as to reduce disposal. The EU in an attempt to deal with the necessity of a meaningful recycling system and at the same time to preserve oil and fossil fuel resources has introduced 2002/96/EC directive [2], which demands 70-80% of WEEEs to be recovered in the form of energy and/or materials [2]. The directive aims at the minimization of the percentage of the solid wastes which will be landfilled or incinerated the full conversion of all waste streams (including plastics) through thermal or mechanic treatment by 2020.

The Feasibility of Using the MFC Concept to Upcycle Mixed Recycled Plastics

“…Waste from electrical and electronic equipment (WEEE) mainly consists of ferrous and non-ferrous metals, glass and plastics. The average plastic content is about 30%, the major components of which are acrylonitrile butadiene styrene (ABS-30%) and high-impact polystyrene (HIPS-25%), followed by polycarbonate (PC-10%), PC/ABS blend (9%) and PP (8%) [44,47]. Even though all these polymers can be separated into mono-streams and recycled into new products [44], questions remain about the level of purity of these streams.…”

CeO2 nanocatalysts for the chemical recycling of polycarbonate

“…Although many efforts to develop effective recycling processes have been proposed, several techniques such as hydrolysis, alcoholysis, and glycolysis have been studied. Moreover, homogeneous catalytic reagents have been used to accelerate the reaction at low temperatures [14][15][16][17]. Regarding the chemical recycling of PC materials, the materials were depolymerized via hydrolysis in the presence of Na 2 CO 3 [18], NaOH [19], and manganese acetate [20] as catalytic reagents, via alcoholysis [21,22], and via glycolysis [23].…”

Design for Circularity Guidelines for the EEE Sector

“…Ongoing innovation in the plastics industry has made it possible to use less material to deliver the same or better functionality. However, the increased diversity and complexity of plastics used in modern devices (such as electrical and electronic equipment (EEE)) has negative impacts on the later stages of a product's lifecycle [3,4].…”

“…WEEE plastics recycling still represents a major challenge, since the plastic fraction is composed of a complex mix of many different polymers and additives. The dominant plastics in WEEE include acrylonitrile butadiene styrene (ABS), high-impact polystyrene (HIPS), polycarbonate (PC), PC/ABS blends, and polypropylene (PP) [3].…”