The transition toward a low-carbon economy requires carbon-capture technologies that combine high efficiency, scalability, and cost-effectiveness. Metal–Organic Frameworks (MOFs) have emerged as promising adsorbents for CO 2 capture owing to their tunable pore structures and surface chemistries, which can be engineered to enhance CO 2 adsorption capacity and selectivity. However, the performance of MOFs is still rarely assessed under realistic process conditions representative of industrial deployment. This study reports the performance of MIL-120(Al), an ultra-microporous, aluminum-based MOF, for post-combustion CO 2 capture using a semi-pilot-scale 3-bed, 6-step vacuum pressure swing adsorption (VPSA) process (1.1 L per column) supported by detailed process simulations. In addition to its environmentally friendly synthesis route, low projected production cost, and excellent hydrothermal stability, MIL-120(Al) exhibits favorable adsorption properties, including a CO 2 uptake of 1.9 mmol/g at 0.1 bar and 298 K and an IAST CO 2 /N 2 selectivity of 104 for a 15/85 mixture at 1 bar and 298 K. Adsorption isotherms and kinetic uptake measurements were used to determine the parameters required for process modeling. The VPSA model was validated against experimental breakthrough curves and subsequently optimized using artificial neural networks coupled with genetic algorithms. Optimal operating conditions were then verified experimentally. For feeds containing 5%, 10%, and 15% CO 2 , MIL-120(Al) consistently achieved high CO 2 purity (>95%) and recovery (>90%). For the 15 vol% CO 2 feed, the process delivered productivities of 1.25–1.53 tCO 2 /(m³.day) with a specific energy consumption of 233–269 kWh/tCO 2 , demonstrating competitive performance relative to pilot-scale studies employing benchmark adsorbents such as zeolite 13X and CALF-20. Semi-pilot validation showed excellent agreement between simulations and experiments, with mean deviations of only 1.17% for purity and 1.75% for recovery. Furthermore, Sobol sensitivity analysis and adsorption-bed profile investigations provided deeper insight into the influence of process parameters and mass-transfer phenomena. These results highlight the strong potential of MIL-120(Al) as a cost-effective and industrially relevant adsorbent for post-combustion CO 2 capture, while providing a robust basis for future techno-economic and life-cycle assessments.
Indirect CO 2 mineralization of Fe-rich serpentinite tailings was evaluated by connecting ammonium sulfate-assisted activation, Mg-Fe separation, carbonate precipitation and salt crystallization across laboratory, engineering and pilot scales. Under the selected activation conditions, 52.08% of the feed Mg was mobilized, and most dissolved Mg was preserved during NH 3 -assisted purification. Hydrated Mg-carbonate formation was supported by XRD and SEM-EDS, and an ammonium sulfate-containing crystalline stream was recovered downstream. Approximately 92% of the mean laboratory Mg-leaching performance was retained on the 1.6 kg/h engineering line. An independent 125 kg/batch pilot campaign was operated for 72 h using cleaned boiler flue gas. Constraints in kiln operation, solids separation and crystallization were identified during scale transfer. Unit-basis screening calculations were used to examine the sensitivity to evaporation demand and fresh-reagent supply. Cross-scale process connectivity was demonstrated, while Mg-based capacities were treated as conditional inventory estimates. Actual carbonate-carbon retention, repeated reagent reuse and net climate benefit were not established by the available measurements.
2,6-dimethylnaphthalene (2,6-DMN) serves as a crucial precursor in the production of the high-performance polyester material polyethylene naphthalate (PEN), possessing extremely high strategic value. Utilizing the coupled CO 2 hydrogenation-naphthalene alkylation reaction system can achieve a ''slow-release'' effect of the methylating agent through the kinetic control of the CO 2 activation step, effectively solving the rapid catalyst deactivation in the traditional direct alkylation process of methanol and naphthalene. Meanwhile, the thermodynamically complementary nature of CO 2 hydrogenation (exothermic) and naphthalene alkylation (endothermic) creates an energy-matched reaction system, significantly enhancing the single-pass conversion of CO 2 . This paper systematically discusses the research progress on the mechanisms and catalyst systems of the CO 2 hydrogenation coupled with naphthalene alkylation process, highlighting the effects of the oxygen vacancy concentration and electronic properties of the metal oxide component in the OX-ZEO bifunctional catalyst on CO 2 activation, as well as the controlling role of the topological structure and acidity of zeolite component on target product shape-selectivity. Additionally, the review analyzes the current challenges and critical research frontiers for this emerging process, including the controlled diffusion of methoxy intermediates and the high-efficiency 2,6-DMN/2,7-DMN isomers separation technologies.
