Activated carbons to CO2 capture from Posidonia Oceanica sea-plant

The goal is to investigate the feasibility to use a local biomass (Posidonia Oceanica), as a raw precursor, to the production of activated carbons (AC) with a high surface area and remarkable CO2 adsorption properties. Pyrolysis experiments were carried out at 400-600 °C with a heating rate of 5° C/min using a biomass particles size between 0.4 to 1.2 mm under a nitrogen atmosphere. Both physical (steam) and chemical (H3PO4, KOH) activation methodologies were carried out in order to obtain porous carbons with the high surface area. Activated carbons with surface area rates of 199÷235 m2/g were obtained by steam and H3PO4 treatments while the activation in presence of KOH has led a noticeable increase in the superficial area (2194 m2/g to 2938 m2/g, related to particles size of the raw biomass). All porous carbons were characterized in terms of elemental analysis (CHNS-O), superficial area and CO2 adsorption measurements (performed by BET ASAP 2020 Micromeritics apparatus at ambient temperature and 1 atm of pressure). CO2 adsorption experiments performed on AC samples led an increase of CO2 capture properties depending both activation methodologies and raw biomass particle size values, from 1.3 to 3.2 mmol/g.