Methodological Guide for Understanding CO2 Capture Quantification and Characterization: A Short Review
The atmospheric concentration of carbon dioxide has surpassed 420 ppm, intensifying global warming and the need for effective mitigation strategies. Carbon capture is a central technology in this effort, traditionally implemented with aqueous amine systems but now expanding to a diverse array of solid and liquid sorbents, including zeolites, metal-organic frameworks, covalent organic frameworks, porous polymers, ionic liquids, deep eutectic solvents, and others. The rapid diversification of capture materials has expanded the analytical toolbox for quantifying CO2 uptake and identifying binding mechanisms but has also created challenges in selecting the most appropriate methodology. Gravimetric and volumetric methods are widely used for porous solids, calorimetry provides access to adsorption energies, and spectroscopic approaches such as nuclear magnetic resonance and infrared spectroscopy resolve molecular speciation in reactive liquids and functionalized sorbents. In this context, the aim of this mini-review is to identify and compare methods, techniques, and instruments capable of performing CO2 capture while simultaneously or subsequently quantifying the amount captured, thus linking the capture process with its analytical evaluation. This work systematizes these methodologies, outlining technical principles, material applicability, limitations, and representative examples, with the goal of guiding method selection and promoting consistent, comparable evaluation across emerging CO2 capture materials.