<scp> CO ₂ </scp> capture by accelerated weathering of limestone using waste limestone at elevated <scp> CO ₂ </scp> concentrations

Abstract BACKGROUND Accelerated weathering of limestone (AWL) using waste limestone (WL) for industrially relevant CO 2 capture remains underexplored. Previous studies on potable water‐operated AWL have mainly examined idealised conditions, such as the use of high‐purity limestone or relatively low CO 2 concentrations, which may not reflect selected industrial flue gas conditions. In addition, the effects of key operating parameters, particularly liquid and gas flow rates, have not been comprehensively optimised for AWL with WL at elevated CO 2 levels. To address these issues, this study investigates the AWL process using WL as packing material, operating under CO 2 concentrations of 15.00% and 20.00%, aiming to evaluate CO 2 capture efficiency and alkalinity at post‐combustion conditions. RESULTS The results showed that higher CO 2 concentration improved AWL performance. The optimised condition for highest alkalinity gave 4.60 mM at 15.00% CO 2 and 5.20 mM at 20.00% CO 2 , while the optimised condition for highest CO 2 capture efficiency gave 85.89% and 88.33%, respectively. CO 2 absorption capacity at 20.00% CO 2 exceeded that at 15.00% CO 2 by 0.83 mol CO 2 ·mol CaCO 3 −1 , whereas the CO 2 absorption rate was approximately 33.8% higher. Furthermore, the analysis of variance (ANOVA) suggested that a quadratic model exhibited strong predictive reliability for both alkalinity and CO 2 capture efficiency. CONCLUSION WL‐operated AWL performs better at higher CO 2 concentrations within the studied range and provides useful experimental and modelling insight for further process development. © 2026 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry (SCI).