A review on plastic waste valorisation to advanced materials: Solutions and technologies to curb plastic waste pollution

Plastic's low cost, versatile and durable nature has rendered it a popular material in the market. Such inevitable high demand has resulted in overwhelming production on a global scale, leading to the generation of a large quantity of plastic waste (PW). The recycling of PW is challenging due to its low degradability and quality loss after each cycle. Large quantities of PW are dumped into the ocean or end up in landfills annually. Due to long-term environmental exposures, plastic degrades into micro-sized particles, which pose severe threats to human health, marine life, and the environment. To overcome this issue, numerous researchers have made efforts to transform PW into useful resources before their degradation into microplastics, which cause secondary pollution. This paper aims to comprehensively review the transformation of PW into advanced materials, fuels, and chemicals through various valorisation technologies. Valorisation technologies including thermal (combustion, torrefaction, pyrolysis, hydrothermal liquefaction, carbonization and one-step hot moulding), biological (microbial and enzymatic degradation) and physical approaches (plastic recycling) that deconstruct plastics into useful chemical intermediates are critically reviewed. The products obtained from the technologies, their resultant properties, and potential applications are highlighted. The detailed studies in these areas could provide insights into sustainable PW management and generate positive economic value. Therefore, further research and development are needed to improve the current technologies to reduce pollution from plastic trash. Collaborative efforts between governments, industries, and research institutes are essential for establishing supportive regulatory frameworks.