Utilizing non-thermal atmospheric plasma (NTAP) for electrified chemical manufacturing and enhanced catalysis

Abstract

As climate change accelerates, decarbonizing the chemical industry, one of the largest contributors to greenhouse gas emissions, has become increasingly urgent. This substantial contribution stems largely from the industry’s heavy reliance on fossil-fuel energy and carbon-intensive thermal processes. Process electrification offers a promising pathway to replace these fossil fuel-based processes with cleaner, more efficient alternatives powered by sustainable electricity. Among these, non-thermal atmospheric plasma (NTAP) emerges as a versatile electrified platform due to its non-equilibrium nature, which enables molecular activation at ambient temperatures and pressures, overcoming activation barriers without the need for combustion-based heating. ☐ This dissertation investigates the application of NTAP to decarbonize chemical production through direct chemical transformations, particularly of plastic waste and its derivatives, as well as through catalyst enhancement. Chapters 2 and 3 explore the chemical transformation of abundant and inert liquid n-alkanes into long-chain oxygenates via the plasma-liquid interface, with Chapter 3 advancing this work through process intensification using a continuous-flow biphasic microreactor. This reactor design enhances the plasma-liquid interfacial area, enabling higher production rates and improved efficiencies, while offering modularity and scalability. ☐ Building on this foundation, Chapter 4 demonstrates the extension of this platform to plastic waste-derived paraffins, enabling the transformation of plastics and biomass waste into renewable surfactants. These hybrid waste-derived surfactants exhibit superior performance compared to commercial surfactants produced from fossil fuels. In Chapter 5, the scope of plasma-assisted plastics upcycling is further expanded through the development of a novel NTAP method for bulk oxidation of polymers such as low-density polyethylene (LDPE). These bulk-oxidized LDPE materials serve effectively as compatibilizers in mixed plastic blends, offering a promising route for recycling mixed plastic waste streams. ☐ Chapter 6 continues the theme of plastics upcycling, shifting focus to the recycling of per- and polyfluoroalkyl substances (PFAS)-coated textiles. We demonstrate that NTAP is a highly effective method for removing polymeric PFAS coatings from UV- and water-resistant textiles, outperforming conventional Soxhlet and microwave extraction. In addition to removing the majority of PFAS coatings, plasma treatment transforms hydrophobic fabrics into hydrophilic ones, thereby enhancing glycolysis depolymerization through improved solvent uptake. ☐ Finally, Chapters 7 and 8 pivot to utilizing NTAP as a surface activation technique for catalyst engineering. Chapter 7 demonstrates rapid surface oxidation activated carbon supports via NTAP, enhancing metal dispersion. Chapter 8 employs a plasma-based method for complete ligand removal from nanocatalysts without altering particle morphology. Both approaches contribute to improved catalytic performance for key biomass transformations. ☐ Collectively, this dissertation establishes NTAP as a powerful electrified technology for decarbonizing chemical production by enabling new pathways for hydrocarbon valorization, engineering advanced catalysts, and advancing sustainable chemical manufacturing.