Improving the carbon dioxide uptake efficiency of activated carbons using a secondary activation with potassium hydroxide

Secondary activation of commercial activated carbon (AC) ORGANOSORB 10-CO was carried out at 600, 700 and 800 C with mass ratios of potassium to AC (K/AC) in range 1–3. Crucial samples have shown following CO2 uptakes and SSA – 3.90 mmol/g and 1225 m2/g, 4.54 mmol/g and 1546 m2/g, 4.28 and 1717 m2/g for pristine material and samples obtained at 700 C with K/AC = 2 and at 800 C with K/AC = 3 respectively. Last sample also indicated signifi cant mesopore volume increase in diameter range 2–5 nm, from 0.11 to 0.24 cm3/g. CO2 uptake increase was explained by formation of micropores up to diameter of 0.8 nm, which distribution was established from CO2 sorption using DFT. Surface chemistry of all samples has not changed during modifi cation, what was proven by XPS. Moreover, deeper incorporation of potassium ions into graphite at higher temperatures was observed as confi rmed with EDS, XPS and XRD.