In addition to climate change, plastic pollution is widely recognized as one of the most severe environmental concerns. Waste plastic-derived advanced materials for carbon capture provide promising solutions to these environmental issues. However, the environmental sustainability and economic feasibility of such a novel approach are still unclear for it to be implemented on an industrial scale globally. As synthesis routes differ in terms of their environmental impact and economic feasibility, we synthesized three waste polyethylene terephthalate (PET) plastic-derived porous carbons (PET6-CO₂-9, PET6-K7, and PET6-KU7) using physical and chemical activation routes. The resulting porous carbons exhibited high CO₂-capture capacities. Based on techno-economic and life-cycle assessments of the scaled-up industrial processes, we showed that the physical CO₂ activation approach performs the best in the reduction of carbon emissions, providing the possibility for carbon neutrality while exhibiting financial viability (net present value of at least €19.22 million over the operating life of the project). Owing to the environmental benefits and economic feasibility of this approach, we highlighted its potential as a multifunctional alternative to conventional CO₂ absorption and plastic waste management technologies.