Literatura académica sobre el tema "Chemical upcycling of polyethylene"

Approximately 380 million tons of plastic are produced annually, and it is projected to rise to nearly 1.1 billion by 2050 [1]. The largest fraction of such waste consists of polyethylene (PE) and polypropylene (PP), which commonly require energy-intensive methods to achieve depolymerization (such as pyrolysis and hydrogenolysis) due to their remarkable thermodynamic stability. Electrochemical methods are a promising alternative for polymer upcycling as they can utilize renewable energy to create an external potential, overcoming the thermodynamic constraints that the C-C bond cleavage endothermicity imposes on low-temperature polymer conversion. They also offer improved chemical process control by manipulating the electrode potential and minimizing the use and storage of hazardous reagents. Electrochemistry provides a broad range of opportunities for establishing green routes to converting plastic into valuable products. Botte's group is investigating electrochemical approaches to convert polyolefins into valuable products like fuels and fatty acids [2]. Our findings indicate that an electrocatalyst in concert with controlled ionic strength and applied potential enable the selective functionalization of polyolefins and their defragmentation towards target molecules regardless of impurities present in the polymer. In this presentation, we will discuss results of the electrochemical functionalization and deconstruction of low-density polyethylene implementing transition metal electrocatalysts. Acknowledgments: The authors would like to acknowledge the financial support of the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Upcycling of Polymers Program, under Award DE-SC0022307 [1] J. E. Rorrer, C. Troyano-Valls, G. T. Beckham, and Y. Román-Leshkov, "Hydrogenolysis of Polypropylene and Mixed Polyolefin Plastic Waste over Ru/C to Produce Liquid Alkanes," ACS Sustainable Chemistry & Engineering, vol. 9, no. 35, pp. 11661-11666, 2021/09/06 2021, doi: 10.1021/acssuschemeng.1c03786. [2] G. G. Botte, "Process for the Electrochemical Up-Cycling of Plastics (US Pending Patent)," U.S. Patent 63040929, 2020.

The exponential increase in production and consumption of plastic has led to accumulation of plastic waste in the environment, resulting in detrimental impacts on human health and the natural environment. Plastic pollution not only stems from discarded plastics but also from the chemicals released during plastic production and decomposition. Various waste management strategies exist for plastic waste, including landfilling, recycling, conversion to liquid fuel, and upcycling. Landfilling, which is a prevalent method, contributes to long-term environmental degradation. Recycling is practiced worldwide, but its percentage remains low, particularly in regions like South Asia. Conversion to liquid fuel through pyrolysis has been explored as a viable solution, although commercialization faces challenges. Upcycling, which involves depolymerization and repolymerization, offers an avenue to recycle plastic waste into valuable chemicals, specifically focusing on high-density polyethylene (HDPE) and low-density polyethylene (LDPE). Currently, HDPE and LDPE make up 36% of all plastic trash by mass, but they have the potential to account for far more. When plastic waste is incinerated or buried in the earth, it generates carbon dioxide and heat, which pollute our environment. Depolymerization is a way to chemically recycle plastic waste into monomers, but this process requires a large amount of energy. Controlled partial depolymerization can transform PE into new, high-quality products at a temperature of more than 400 °C with or without a catalyst. In this study, we provide a novel approach for the conversion of plastic waste, particularly HDPE and LDPE, into valuable alkyl aromatics. By implementing controlled partial depolymerization, we propose a plant design capable of transforming plastic waste into high-quality chemicals. The design aims to optimize energy consumption, process efficiency, and product quality. The research findings contribute to sustainable plastic waste management and the reduction in environmental pollution caused by plastic waste.

Recycling plastic waste into valuable materials is one of the contemporary challenges. Every year around 50 million tons of polyethylene terephthalate (PET) bottles are used worldwide. The fact that only a part of this amount is being recycled is putting a burden on the environment. Therefore, a technology that can convert PET-based waste materials into useful ones is highly needed. In the present work, attempts have been made to convert PET-based waste materials into a precursor for others. We report an aminolysed product (3) obtained by aminolysis reaction of PET (1) with 1,2 diaminopropane (DAP, 2) under solvent and catalytic free conditions. The highest amount of monomeric product was obtained upon heating the mixture of diamine and PET at 130 °C. The resulting aminolysed product was then converted to a Schiff-base (5) in 25% yield. The chemical structure of the synthesized compounds was confirmed using multi-spectroscopic techniques. The results of this study will be a valuable addition to the growing body of work on plastic recycling.

Polyethylene terephthalate (PET) is one of the most commonly used polyester plastics worldwide but is extremely difficult to be hydrolyzed in a natural environment. PET plastic is an inexpensive, lightweight, and durable material, which can readily be molded into an assortment of products that are used in a broad range of applications. Most PET is used for single-use packaging materials, such as disposable consumer items and packaging. Although PET plastics are a valuable resource in many aspects, the proliferation of plastic products in the last several decades have resulted in a negative environmental footprint. The long-term risk of released PET waste in the environment poses a serious threat to ecosystems, food safety, and even human health in modern society. Recycling is one of the most important actions currently available to reduce these impacts. Current clean-up strategies have attempted to alleviate the adverse impacts of PET pollution but are unable to compete with the increasing quantities of PET waste exposed to the environment. In this review paper, current PET recycling methods to improve life cycle and waste management are discussed, which can be further implemented to reduce plastics pollution and its impacts on health and environment. Compared with conventional mechanical and chemical recycling processes, the biotechnological recycling of PET involves enzymatic degradation of the waste PET and the followed bioconversion of degraded PET monomers into value-added chemicals. This approach creates a circular PET economy by recycling waste PET or upcycling it into more valuable products with minimal environmental footprint.