Sustainable Upcycling of Waste into Carbon Nanomaterials for Catalytic Environmental Remediation Wen-Da Oh*
School of Chemical Sciences, Universiti Sains Malaysia
*Email: ohwenda[at]usm.my
Abstract
The annual generation of plastic waste is increasingly becoming a significant environmental concern. In Malaysia, more than 1 million tons of plastic waste are generated yearly. An effective approach to managing plastic waste while incentivizing its collection is to transform it into valuable carbon nanomaterials. In this study, we explored the sustainable upcycling of plastic waste into carbon nanotubes (CNTs, with market size of >USD5 billion) through a one-pot catalytic pyrolysis process. The two key parameters for achieving high-quality and high-yield CNT production are catalyst design and operational conditions. A Ni-based catalyst consisting of NiMoCa was developed to convert polypropylene waste into CNTs. Typically, Ni acts as the active site for CNT growth while Mo and Ca as carbon reservoir and support, respectively. The catalyst-to-polypropylene waste ratio, pyrolysis temperature, and pyrolysis duration were systematically varied to investigate their effects. The results showed that well-defined CNTs with a length of ~30 nm and a purity of 95-98 wt.% can be successfully obtained, with a carbon yield of 5-6 wt.% under the optimum conditions. The plastic-derived CNTs was then functionalized with nitrogen and used to remove pollutants such as antibiotics from contaminated water. This study successfully demonstrated the sustainable conversion of waste into functional materials within a circular economy framework.
