Superior CO_2 capture performance on biomass-derived carbon/metal oxides nanocomposites from Persian ironwood by H_3PO_4 activation

摘要

In the present study, efficient CO2 capture onto the nanostructured Persian ironwood biomass-derived activated carbon/metal oxides (AC/MOs) composites under different conditions, was developed. The as-synthesized highly porous AC, with the chemical activation method using H3PO4, was modified by the carbonization of a single and a binary mixed-MO for the first time. The optimization process of the synthesized adsorbents was conducted considering the different parameters comprising the application of different ratios of activating agent and activation temperatures, various ratios of metal loading, and the diverse temperature treatments to develop the desired MOs. The results illustrated that besides the development of MOs, the textural properties of ACs were significantly improved. Modified ACs showed a higher capture capacity compared to unmodified ones due to the simultaneous physisorption and chemisorption mechanisms for CO2 adsorption. Among all the sorbents, HP5/Cu3-1 demonstrated the highest CO2 adsorption capacity with 6.78 mmol/g, indicating a 124.5% enhancement in comparison with the unmodified AC (3.02 mmol/g) at 1 bar and 30 degrees C. The synthesized binary mixed oxide, HP5/AlMg8-1, also illustrated the increase of adsorption capacity in comparison with its related single oxides (i.e. HP5/Al5-1 and HP5/Mg8-1). Furthermore, after 10 successive adsorption/desorption runs, the adsorption efficiency of the reused HP5/CuNi3-1 decreased by 2.07%.