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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. [ABSTRACT FROM AUTHOR]

In this work, a comprehensive study of CO2 methanation by coupling process simulation, economic analysis, and life cycle assessment (LCA) was conducted to find out the most practicable pathway for green methane production in terms of technical, economic, and environmental aspects. For this work, different renewable energy resources, such as hydropower, wind power, and solar power, and water electrolysis, like alkaline water electrolysis (AWE) and proton-exchange membrane water electrolysis (PWE), leading to 6 scenarios for H2 production were considered. From the economic analysis in terms of itemized cost estimation, the levelized cost of methane (LCOM) for scenarios 1 to 6 was obtained as 0.108, 0.118, 0.144, 0.121, 0.132, and 0.159 $ kWh−1, respectively. In addition, from LCA, the respective quantified environmental impacts (i.e., CO2 emission) were obtained as 0.347, 0.813, 2.33, 0.537, 0.842, and 2.52 kg CO2-eq kg H2−1 for scenarios 1 to 6, respectively. And then, the analytic hierarchy process (AHP) was carried out to decide on the most appropriate renewable energy and water electrolysis based on different criteria of renewable energy capacity with Technology readiness level (TRL) of water electrolysis, LCOM, and CO2 emission for technical, economic, and environmental criteria, respectively. From this work, H2 production from AWE with wind power (i.e., scenario 2) was selected to be the best pathway for green methane production owing to the narrow priority range of 0.130–0.191. Furthermore, scenario 5 (i.e., PWE with wind power) was determined to be the second pathway with the same reason. [ABSTRACT FROM AUTHOR]