Microplastic Waste to Functional Carbon Materials

Microplastic pollution is a persistent environmental challenge due to the widespread distribution, chemical stability, and continuous generation of polymeric particles smaller than 5 mm.Instead of relying only on separation, filtration, or destruction, microplastics can be considered carbon-rich secondary feedstocks for producing functional carbon materials, linking plastic-waste management with green chemistry and circular-economy principles.Technologies such as pyrolysis, hydrothermal carbonization, catalytic carbonization, microwave processing, flash Joule heating, and plasma conversion can transform polymeric waste into porous carbons, activated carbons, graphene-like materials, carbon nanotubes, and carbon dots for applications in adsorption, photocatalysis, advanced oxidation, CO₂ capture, and electrochemical treatment.However, feedstock heterogeneity, additives, halogen-containing polymers, energy demand, chemical activation, contaminant transfer, and material safety remain important challenges.This review critically examines microplastic-to-carbon conversion, polymer-carbon property relationships, environmental applications, regeneration, end-of-life management, and life-cycle assessment.A future framework integrating selective recovery, low-energy conversion, safer activation, multifunctional remediation, AI-assisted materials design, and circular life-cycle assessment is proposed to shift microplastic management from a linear "capture-and-dispose" model toward a circular "recover-convert-remediate-regenerate" strategy.