Preparation of nanoporous activated carbon and its application as nano adsorbent for CO2 storage

Nanoporous activated carbons, as adsorbent for CO 2 storage, were prepared from walnut shells via two chemical processes including phosphoric acid treatment and KOH activation at high temperature. Specific surface area and porosities were controlled by KOH concentration and activation temperature. The obtained adsorbents were characterized by N2 adsorption at 77.3 K. Their carbon dioxide adsorption capacities were measured at different pressures at 290 K by using volumetric adsorption equipment. The KOH-treated nanoporous carbons typically led to the production of high specific surface areas and high micropore volumes and showed better performance for CO 2 adsorptions. The maximum experimental value for adsorption capacity happened when pressure increased from 5 to 10 bar (1.861-2.873mmol·g −1 ). It was found that in order to improve the highest capacity of CO 2 adsorption for KOH-modified carbon (9.830-18.208mmol·g −1 ), a KOH: C weight ratio of 3.5 and activation temperature of 973 K were more suitable for pore development and micro-mesopore volume enhancement.