Generation of High Yields of Carbon Nanotubes (CNTs) Using Recycled Metal Catalysts

INV-20045

 

This technology relates to the upcycling of waste plastics to value-added products, in this case carbon nanomaterials, such as carbon nanotubes (CNTs). This invention is exemplified in a method where metallic substrates are used as catalysts for the growth of nanotubes. The feedstock consists of polymers or other organic materials, such as biomass. The CNTs are generated using the hydrocarbon-rich pyrolysis or oxidation products as carbon donors. These stainless steel substrates can be of various configurations, including, but not limited to, wire cloths, particles, waste chips, and shreddings. 

This invention pertains to the efficient up-cycling of waste post-consumer plastics. Such materials are converted to value-added products.

 

In this invention, the CNTs are generated using the hydrocarbon-rich pyrolysis or oxidation products as carbon donors. The catalyst substrates are first immersed in an acid bath and then exposed to oxidative and thermal treatments to break up their protective chrome layer and activate their surfaces for nanocarbon generation. Thereupon, the ensuing pyrolyze gases are passed by the substrates to catalytically grow CNTs on their surfaces. CNTs are then removed from the substrates by sonication in alcohol. After removal of the grown CNTs from the catalyst substrates, the SAID substrates are collected, subjected to specific treatments, and then they are recycled numerous times to generate CNTs. Recycling the same catalyst several times not only improves the CNT yields but also greatly reduces the operating costs of the process associated with the purchase of catalysts, and reduces the volumes of the waste streams.

 

- The oils can be condensed and removed for further use and the gases can be converted to value-added carbon nanotubes with exceedingly high efficiencies when recycled stainless steel catalysts are introduced to the process

- Enables drastic increases in the yield of the value-added product of carbon nanomaterials

- Remaining unreacted pyrolyze hydrocarbon gases can be burned to generate heat for the process

 

- Conversion of waste organic materials into value‑added products

- It can be used to strengthen nanocomposites for structural materials

 

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