Recent Studies and Technologies in the Separation of Polyvinyl Chloride for Resources Recycling: A Systematic Review

Abstract

Material recycling and thermal treatment are the two most common recycling methods employed for plastic waste management. Thermal treatment for energy recovery is more widely applied compared with material recycling because the latter requires a high efficiency of separation and a high purity of products. Unfortunately, certain plastics like polyvinyl chloride (PVC) are unsuitable for thermal treatment because they contain additives like chloride (Cl−) that have adverse effects on refractory materials used in boilers. As a result of this, mixed plastic wastes containing PVC generally end up in landfills. PVC-bearing mixed plastics, however, remain valuable resources as championed by the United Nation Sustainable Development Goals (UN-SDGs): Goal 12 “Responsible production and consumption”, and their recycling after the removal of PVC is important. In this paper, recent studies (2012–2021) related to the separation of PVC from other types of plastics were systematically reviewed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 66 articles were selected, reviewed, and summarized. The results showed that various separation technologies conventionally applied to mineral processing—selective comminution, gravity separation, magnetic separation, electrical separation, and flotation—have been studied for PVC separation, and the majority of these works (>60%) focused on flotation. In addition, more advanced technologies including sorting and density-surface-based separation were introduced between 2019 and 2021.

Recent advances in polyvinyl chloride (PVC) recycling

“…Potential solutions may involve the development of specialized separation techniques tailored to the specific interactions between PVC and plasticizers, as well as the optimization of recycling processes to minimize contamination. [75][76][77] Moreover, ongoing research endeavors are aimed at formulating PVC compositions that are recyclable and contain lower levels of plasticizers, or exploring alternative plasticizers that can be separated from PVC more effectively. These efforts have the potential to enhance the sustainability of PVC recycling practices.…”

Chlorinated plastics offer unique opportunities and challenges in upcycling

“…Despite these issues, it would be a misconception to classify PVC as non‐recyclable, 6 especially with the fact that PVC waste sorting 7 and recycling technologies are in constant advancement. Nonetheless, the investigation of chemical recycling methods for PVC is worthwhile to pursue in parallel.…”