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 CO 2 /N 2 separation. The adsorbents were prepared using the chemical activation procedure employing different activating agents, namely H 3 PO 4 , ZnCl 2 , and KOH, at various impregnation ratios (1, 2, 3) and carbonizing temperatures (500, 650, and 800 °C). The pore structures, morphology, and CO 2 selectivity of the fabricated adsorbents were evaluated. ZnCl 2 -activated carbon (ACZn1) exhibited the highest specific surface area of 1925 m 2 .g − 1 , while H 3 PO 4 -activated carbon (ACH3) demonstrated higher CO 2 uptake of 25.848 mmol.g − 1 estimated based on the Sips model at 298 K, due to its excellent pore volume (1.351 cm 3 .g − 1 ). The estimated IAST CO 2 /N 2 selectivity under the environmental conditions for ACH3, ACZn1, and ACK1-Char adsorbents was 19.64, 20.24, and 9.34, respectively.