مقاله انگلیسی رایگان در مورد جداسازی مبتنی بر حلال و بازیافت پلاستیک های زباله – الزویر 2018

Since the creation of first man-made plastic, the global production and consumption of plastics have been continuously increasing. However, because plastic materials are durable and very slow to degrade, they become waste with high staying power. The over consumption, disposal, and littering of plastics result in pollution, thus causing serious environmental consequences. To date, only a fraction of waste plastics is reused and recycled. In fact, recycling plastics remains a great challenge because of technical challenges and relatively insufficient profits, especially in mixed plastics. This review 19 focuses on an environmentally friendly and potentially profitable method for plastics separation and recovery and solvents extraction. It includes the dissolution/reprecipitation method and supercritical fluid extraction, which produce high-quality recovered plastics comparable to virgin materials. These methods are summarized and discussed taking mass-produced plastics (PS, PC, Polyolefins, PET, ABS, and PVC) as examples. To exploit the method, the quality and efficiency of solvent extraction are elaborated. By eliminating these technical challenges, the solvent extraction method is becoming more promising and sustainable for plastic issues and polymer markets.

Introduction

The challenge of the disposal of accumulated waste plastics and corresponding environmental issues have received widespread attention from the public and academicians (Rochman et al., 2013; Jambeck et al., 2015). Waste plastics can turn into the resources for new plastic products; thus, a cyclic economy can be achieved by coupling waste prevention with material recycling. For example, a sequential extraction process using mixed solvents to recover polycarbonates can obtain a high yield (>95%) and high purity similar to virgin polycarbonates recycled product using less energy (Weeden et al., 2015). Although green chemistry has grown remarkably (Cui et al., 2011), large amounts of waste plastics remain for safe disposal and reutilization. Recycling plastics can also be viewed as a big business because of its potential environmental benefits and economic profits. However, about 6300 million metric tons of plastic waste have been generated until 2015, and only 9% of them are recycled, 12% are incinerated, and 79% are discarded (Fig. 1) (Geyer et al., 2017). Taking the fastestgrowing component of the municipal solid waste stream as an example, electronic waste (e-waste, global generation 20–50 million tons/year (Robinson, 2009; Herat and 45 Agamuthu, 2012)) contains valuable plastics (~30%) (Gramatyka et al., 2007). In fact, ewaste plastics consist of heterogeneous polymers, which makes the recycling process difficult (Schlummer et al., 2006; Ignatyev et al., 2014), such as ABS, PC, SAN, PS 48 (Beigbeder et al., 2013), PP, and PET (Martinho et al., 2012).