Preparation and characterization of low-cost chemically activated carbons using H3PO4, ZnCl2 and KOH for CO2 adsorption applications.

In the present research, Parrotia Persica wood was used as a low-cost precursor to developing activated carbons (ACs) for CO2/N2 separation. The adsorbents were prepared using the chemical activation procedure employing different activating agents, namely H3PO4, ZnCl2, and KOH, at various impregnation ratios (1, 2, 3) and carbonizing temperatures (500, 650, and 800 °C). The pore structures, morphology, and CO2 selectivity of the fabricated adsorbents were evaluated. ZnCl2-activated carbon (ACZn1) exhibited the highest specific surface area of 1925 m2.g- 1, while H3PO4-activated carbon (ACH3) demonstrated higher CO2 uptake of 25.848 mmol.g- 1 estimated based on the Sips model at 298 K, due to its excellent pore volume (1.351 cm3.g- 1). The estimated IAST CO2/N2 selectivity under the environmental conditions for ACH3, ACZn1, and ACK1-Char adsorbents was 19.64, 20.24, and 9.34, respectively.