Experimental Fern leaves were us as a carbon source. Production of activated carbons: impregnation by dry KOH (mass ratio KOH: carbon source, 1:1) during 1 h, drying at 200°C, carbonisation for 1h, under nitrogen at 600-900°C, washing with distilled water, treating with 1 M HCl for 19 h, washing with distilled water until neutral, drying at 120°C. The specific surface area (SBET), a total pore volume (Vp), and micropore volume V (mic) were estimated by nitrogen sorption at a temperature of -196.15 °C. These values are shown in Table 1. Results and Discussion The highest specific surface area of 2049 m2/g total pore volume (Vp) – 1.00 cm3/g and micropores pore volume (Vmic) – 0.73 cm3/g was sample F800. The largest adsorption of CO2 was observed at 25°C on activated carbon F600 and amounted to 4,36 mmol/g. Table 1. The values of specific surface area pore volume, micropore and adsorption of CO2 at 25ºC (ACO2) Name of sample BET m2/g Vp [cm3/g] Vmic [cm3/g] ACO2 [mmol/cm3] F600 913 0.40 0.30 4.36 F700 1587 0.68 0.57 4.15 F800 2049 1.00 0.73 4.25 F900 1692 0.99 0.65 3.74 Conclusions The fern leaves precursor is found to be a good raw material for developing activated carbons with a desirable pore size distribution. Activated carbons derived from fern leaves by chemical modifications shown-developed porous structure and surface area, which had an impact on their good sorption ability. The study showed that the activated carbons production from the fern leaves is a good sorbent used to capture CO2.