‏CO₂ Separation Technologies for Achieving Net-Zero Emissions: A Comprehensive Review of Advances and Barriers

Carbon dioxide (CO₂) is the primary greenhouse gas responsible for global warming and climate change. Its atmospheric concentration has risen from about 280 ppm in pre-industrial times to over 420 ppm in 2025 and continues to increase. Achieving net-zero emissions by 2050 requires the urgent development and large-scale deployment of carbon capture, utilization, and storage (CCUS) technologies.

This comprehensive review explores the main CO₂ separation technologies, including chemical and physical absorption, adsorption (particularly amine-functionalized porous polymers), membrane separation, cryogenic processes, and hybrid systems. Recent advances in amine-based materials, polymeric adsorbents, and hybrid membrane contactors are discussed in detail. Modeling approaches such as the Group Method of Data Handling (GMDH) for predicting CO₂ uptake on porous polymers are also examined.

A systematic comparison of these technologies is presented based on energy consumption, capture cost, selectivity, regeneration methods, and technology readiness level (TRL). Finally, major challenges including high energy penalty, oxidative degradation, scalability issues, and economic barriers are analyzed, along with future research directions and policy recommendations for the practical implementation of CCUS at scale. Abstract words limit