Highly efficient CO2 adsorption of corn kernel-derived porous carbon with abundant oxygen functional groups

The porous carbon (CKC-X-Y, CKC is the corn kernel-derived carbon; Xis the activation temperature; and Y is the KOH/CKC mass ratio (2, 3, 4, and 5)) adsorbents were prepared from corn kernels by the KOH activation method. Textural property and oxygen functional group amount of the CKC-X-Y sample were influenced by the activator amount and activation temperature. Among the CKC-X-Y samples, the CKC-900-3 sample displayed the highest surface area (1943 m(2)/g) and the largest pore volume (1.10 cm(3)/g), whereas the CKC-900-4 sample possessed the highest amount (45.5 %) of oxygen functional groups. The CKC-900-4 sample exhibited the largest CO2 adsorption capacity (3.63 mmol/g at 25 degrees C) among all of the CKC-X-Y samples. The results indicate that the activated corn-derived porous biochar with a high surface area and a high oxygen functional groups amount possessed a large CO2 uptake. In addition, the CKC-X-Y samples showed high CO2/N-2 selectivity, good recyclability, and easy regeneration behavior. The adsorption of CO2 was physically and chemically adsorbed on the surface of the CKC-X-Y samples, with the physical adsorption being dominant. In which CO2 was mainly chemically adsorbed on the samples with hydroxyl groups.