Comparative Analysis of CO₂ Adsorption Performance of Bamboo and Orange Peel Biochars

Carbon capture and sequestration (CCS) is an essential strategy for mitigating greenhouse gas emissions and addressing climate change. In this study, the biochar of bamboo and orange peel (BB and OPB) are synthesized and appraised as potential CO₂ adsorbents. Comprehensive characterizations viz. sorption isotherm, FTIR spectroscopy, and SEM-EDS reveal substantial differences in their structural and functional properties. OPB exhibits a significantly higher BET surface area (40.13 m²/g) compared to BBs (7.38 m²/g). FTIR and EDS analyses further demonstrate more amine, carboxylic, ester, and ether functional groups in OPB, indicating its affinity for CO₂ molecules. The CO₂ adsorption isotherm shows a higher adsorption capacity (22.83 cm³/g) in OPB than BB (14.12 cm³/g) at 273 K and 1 bar. The adsorption process is augmented by mesoporous structures and interactions between surface functional groups and CO₂ molecules. The thermogravimetric analysis further reveals the higher CO₂ uptake capability of OPB than BB. This result also shows that the CO₂ uptake stabilizes after 48 h for both the biochars. These results highlight the potential of OPB as an efficient CCS material, demonstrating the importance of specific biochar properties in the development of CO₂ capture.