The problem of polyethylene waste - recent attempts for its mitigation

Abstract

For the past two decades, with the increase in plastic consumption came a rise in plastic waste, with the bulk of it ending up in landfills, incinerated, recycled or leaking into the environment, especially in aquatic ecosystems. Plastic waste poses a significant environmental threat and a wealth issue due to its non-biodegradability and recalcitrant nature. Polyethylene (PE) remains one of the major utilized polymers in different applications amid all the other types because of its low production costs, simplistic nature prone to be modified and historically predominant researched material. Since the common methods for plastic disposal are troubled by limitations, there is a growing need for more appropriate and environment friendly methods alternatives. This study highlights several ways that can be used to assist PE (bio)degradation and mitigate its waste impact. Biodegradation (microbiological activity driven) and photodegradation (radiation driven) are the most promising for PE waste control. The shape of the material (powder, film, particles, etc.), the composition of medium, additives and pH, temperature and incubation or exposure times contribute to plastic degradation efficiency. Moreover, radiation pretreatment can enhance the biodegradability of PE, providing a promising approach to fighting plastic pollution. This paper relates the most significant results regarding PE degradation studies followed by weight loss analysis, surface morphology changes, oxidation degree (for photodegradation) and mechanical properties assessment. All combined strategies are very promising to minimize the polyethylene impact. However, there is still a long way to go through. The degradation kinetics is still low for the currently available biotic or abiotic processes, and complete mineralization is thoroughly unseen.

Keywords: Biodegradation; Photo-pretreatment; Photocatalysis; Photodegradation; Photolysis; Polyethylene.