CO<sub>2</sub> Capture from Porous Carbons Developed from Olive Pruning Agro-Industrial Residue
Pamela B. Ramos, Arminda Mamaní, María Erans, Florencia Jerez, Marcelo F. Ponce, Fabiana Sardella, Amaya Arencibia, Marcela A. Bavio, Eloy S. Sanz-Pérez, R. Sanz
Abstract
This work studied the synthesis of activated carbons (ACs) from olive tree pruning waste since the recovery of this abundant residue for producing AC is a sustainable and environmentally friendly alternative. The physical and KOH-chemical activation processes were compared and analyzed to obtain an appropriate carbon for the adsorption of CO 2 . Highly microporous carbons were obtained after KOH chemical activation that exhibit high surface area (3526 m 2 g –1 ), micropore volume (1.20 cm 3 g –1 ), and total volume (1.79 cm 3 g –1 ). The equilibrium and kinetic behavior of carbons for CO 2 adsorption were studied using Langmuir, Freundlich, and Temkin models for the isotherms and pseudo-first-order and pseudo-second-order models for the kinetics. The chemically activated carbon was found to be the most appropriate for the capture of CO 2 at low and high CO 2 pressures, showing an adsorption capacity of 5.1 mmol g –1 at 0 °C and 1 bar. The estimated isosteric heat indicates that the CO 2 adsorption process was feasible and confirms the pure physical adsorption of CO 2 . The chemically activated carbon allowed ten reuse cycles, maintaining the capture capacity. These results confirm that ACs from olive tree pruning residue have suitable capacity and stability for application as CO 2 adsorbents.