Capturing CO₂ through High Surface Area Activated Carbon Derived from Seed Shells of Balanites Aegyptiaca

Activated carbon is an attractive adsorbent for capturing various environmental pollutants, including CO₂. Herein, an optimal synthesis and impressive performance of activated carbon made from Balanites aegyptiaca (Desert date) seed shells is reported, which is an abundant agricultural waste in the Middle East and Africa. The synthesis route involved pretreating the biomass with KOH and heating it under a suitable temperature profile. An optimal KOH-to-biomass ratio and multi-stage carbonization yielded activated carbon with a surface area above 3000 m²/g and an average pore size of nearly 4.1 nm. At 0 °C, this activated carbon exhibited CO₂ uptake of 11.3 mmol g⁻¹ that surpassed the uptake capacity of previously reported activated carbons. The selectivity towards CO₂ was also found to be significantly higher compared to other gases. Thus, the present approach demonstrates an efficient conversion of agricultural waste to activated carbon for capturing CO₂ and other environmental contaminants.