Assessing the Feasibility of Zeolite-Based Dual-Function Aerosols for Stratospheric Carbon Capture and Solar Radiation Management

Stratospheric aerosol injection (SAI) is a prominent candidate for solar radiation management (SRM), with growing interest in combining it with in-situ carbon dioxide (CO₂) capture. This study evaluates the feasibility of using zeolite-based aerosols in dual-function SAI systems—providing both radiative forcing and CO₂ adsorption. Using Langmuir isotherm-based adsorption modeling and thermodynamic simulations under representative stratospheric conditions (~0.05 atm, low temperatures), it is found that zeolite performance degrades by over 99.97% relative to ground-based direct air capture (DAC) scenarios. Additionally, achieving significant radiative impact would require the deployment of over 10⁹ micro-scale delivery units. These findings indicate that zeolites are fundamentally unsuitable for airborne CO₂ capture and limited in their SRM potential as currently conceived. While the dual-function concept proves infeasible in its present form, the results contribute to atmospheric engineering research by identifying critical constraints and informing future pathways for climate intervention design.