Solvent-Mediated Recycling of Multicomponent Plastic Waste
ORAL · Invited
Abstract
Plastics are ubiquitous in all facets of everyday life. Globally, over 400 million metric tons of plastic are produced per year. Most plastic waste consists of complex mixtures of polymers, intentionally added substances, and non-intentionally added substances (i.e., contaminants). This complexity significantly inhibits existing plastics recycling processes. Consequently, most plastics today are diverted to landfills or incineration. There is an urgent need for new, economically viable, and sustainable technologies to recycle – or upcycle – plastic waste to address these long-term environmental challenges. We recently developed the Solvent-Targeted Recovery and Precipitation (STRAP) process with collaborators as a platform technology for recycling multicomponent plastic waste. In this process, target polymer components are recovered from plastic waste using sequential solvent washes. Each wash is designed to selectively dissolve a single component, which can then be recovered after precipitation. The STRAP process has exhibited potential for the recovery of high-quality resins from multilayer plastic films and offers environmental advantages over fossil-based plastic film production. In this talk, I will describe our approaches to design STRAP processes for a variety of real-world feedstocks by integrating molecular simulations, experiments, and machine learning to select solvent systems, assess process economics and life cycle metrics, and characterize recovered materials. I will summarize our development of computational tools for rapid solvent selection by quantitatively predicting temperature-dependent polymer solubilities. I will further describe our methods for integrating computational modeling with experiments to identify solvents for removing contaminants, such as inks, from plastic waste, while identifying molecular mechanisms underlying their removal. Finally, I will describe recent experimental applications of STRAP to flexible packaging waste and the properties of films created from recovered materials.
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Publication: T. W. Walker, N. Frelka, Z. Shen, A. K. Chew, J. Bannick, S. Grey, J. A. Dumesic, R. C. Van Lehn, and G. W. Huber. "Recycling of multilayer plastic packaging materials by solvent-targeted recovery and precipitation." Science Advances, 2020, 6 (47), eaba7599.<br><br>P. Zhou, K. L. Sánchez-Rivera, G. W. Huber, and R. C. Van Lehn. "Computational approach for rapidly predicting temperature-dependent polymer solubilities using molecular-scale models." ChemSusChem, 2021, 14 (9), 4307-4316.<br><br>P. Zhou, J. Yu, K. L. Sanchez-Rivera, G. W. Huber, and R. C. Van Lehn. "Large-scale computational polymer solubility predictions and applications to dissolution-based plastic recycling." Green Chemistry, 2023, 45, 4002-4014.<br><br>K. L Sanchez-Rivera, C. Granger, H. Appiah, K. Nelson, S. Grey, D. Sun, J. E. Garcia, E. Chen, Z. Xu, T. A. Osswald, L-S. Turng, A. McDonald, R. C. Van Lehn, E. Bar-Ziv, G. W. Huber. "Cast film production with polyethylene recycled from a post-industrial printed multilayer film by solvent-targeted recovery and precipitation." ACS Materials Letters, 2024, 6 (9), 4042-4050.<br><br>K. L. Sanchez-Rivera, A. del Carmen Munguia-Lopez, P. Zhou, V. S. Cecon, J. Yu, K. Nelson, D. Miller, S. Grey, Z. Xu, E. Bar-Ziv, K. L. Vorst, G. W. Curtzwiler, R. C. Van Lehn, V. M. Zavala, G. W. Huber. "Recycling of a post-industrial printed multilayer plastic packaging film containing polyurethane inks by solvent-targeted recovery and precipitation." Resources, Conservation & Recycling, 2023, 197, 107086.
