دانلود رایگان مقاله انگلیسی جداسازی مبتنی بر حلال و بازیافت پلاستیک های زباله - الزویر 2018

Abstract

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.

5. Conclusion and outlook

Despite the environmentally friendly properties including energy saving and less CO2 emission of the current solvent extraction of waste plastics technique (Weeden et al., 2015; Zhao et al., 2017), it still faces difficulties and challenges, which hinder its development to some extent. Generally, waste plastics are mixed polymers. Therefore, the primary challenge is the separation and recycling of waste components one by one (Hopewell et al., 2009). It is not difficult to understand why those foregoing research mainly focused on the recycling of single plastic and rarely discussed the disposal of mixed plastics waste. On the one hand, the dissolution of mixed plastics in solvents (pure or mixed) is complex and differ from that of individual plastic, because of the interactions between the solutes. On the other hand, inappropriate formations such as gel from sequential extraction always hinder the further separation due to difficulties in centrifugation or filtration. More recently, investigations on separation and recovery of multiple plastics have emerged (Hadi et al., 2012; Zhao et al., 2017).