Influence of Mechanochemical Pre-Treatment on the CO₂ Capture Performance of Petcoke-Derived Activated Carbon

Carbon dioxide (CO₂) capture is a cost-effective strategy to mitigate global warming. Petroleum coke (petcoke), a low-cost byproduct of oil refining, is often discarded improperly, contributing to environmental pollution and public health issues. Transforming petcoke into porous activated carbon offers a sustainable pathway for both waste valorization and CO₂ capture. However, challenges such as poor porosity, high sulfur content, and particle agglomeration hinder direct activation. This study investigates the impact of mechanochemical pretreatment via wet and dry ball milling followed by thermal treatment and KOH activation on the structure and CO₂ adsorption performance of petcoke-derived activated carbon. Characterization using XRD, SEM, BET, and FT-IR confirmed significant structural and chemical enhancements. Wet ball milling produced materials with higher surface area (1831 m²/g) and CO₂ uptake (3.51 mmol/g at 273 K) compared to dry milling (1389 m²/g; 3.34 mmol/g), due to better size reduction and functionalization. While ethanol-assisted wet milling enhances performance and it introduces cost-related trade-offs for industrial scale-up. Future work will explore greener, cost-effective solvent systems to maintain the benefits of wet milling. Overall, this study supports the scalable use of petcoke-derived activated carbon for post-combustion CO₂ capture and promotes sustainable waste-to-resource strategies.