Upcycling Ocean-based Plastics for Sustainable Feedstock Supply Chain

Plastics are ubiquitous in modern life. Global production of plastics has reached about 400 million tons annually. Total plastics production has increased by 36% in the past decade and is estimated to grow to 700 million tons in 2030. Over 10% of used plastics ends up in the ocean. Ocean vortices form “garbage patches” or “stomachsize colorful plastic piles” of disposed plastics and attracts seabirds. Slow photo degradation of plastics forms microscopic pieces, creating waterborne pollutants and leaching toxins, and causing health risks to ocean life and humans through the food chain. Often the gravity of this environmental challenge is expressed as “nearly every seabird may be eating plastic by 2050”. The challenges of plastics and increasing sustainable feedstock demand can be simultaneously addressed by proper characterization of ocean plastics and their selective depolymerization into plastics’ building block chemicals to produce upcycled plastics. Currently a small fraction of postconsumer plastics is recycled through mechanical processing. The mechanical recycling technology causes significant loss in the properties of plastics. Thus, the recycled materials are used for low value applications, which is often referred to as ‘carbon downcycling’. RiKarbon is commercializing an enabling technology, RiPURPOSETM RiKarbon’s Prudent Upcycling of Refuse Plastics for Ocean Sustainability and Environment to capture higher value for postconsumer polyethylene terephthalate PET plastic waste. It entails development of lowcost ocean PET feedstock, a major fraction of ocean mixed plastics, and its selective depolymerization into PET’s building block chemicals for manufacturing renewable PET. It will 1 mitigate environmental challenges of waste plastics, 2 ‘upcycle’ plastic’s carbon value, 3 create a sustainable feedstock for waste plastic, 4 reduce our dependence on petroleum, 5 improve future energy security, 6 reduce global CO2 footprint by introducing renewable chemicals for PET, and 7 create a circular economy. Our phase I accomplishments exceeded the proposed technical milestones. We studied the effect of PET particle sizes on selective depolymerization, characterized ocean mixed plastics contaminates and composition, studied the effects of ocean plastic contaminates in the selective depolymerization, optimized depolymerization reaction parameters, and completed initial technoeconomic analysis. In Phase II, RiKarbon will expand feedstock collection from different locations in the ocean body to map the contaminates in the feedstock and their selective depolymerization. Other technical milestones of the phase II are: depolymerization of lowcost waste plastics, e.g., modified, color and degenerated PET wastes, development and optimization of separation technology for market ready depolymerized products, polymerization of depolymerized products to new PET, pilot scale demonstration of the RiPURPOSETM technology, and detailed technoeconomic and lifecycle analyses.