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.

Automated summary

The study found that high activation temperature and activator amount can enhance the textural properties and oxygen functional groups of corn kernel-derived porous carbon adsorbents, thereby increasing their CO2 adsorption capacity and selectivity.