Influence of oxidation upon the CO2 capture performance of a phenolic-resin-derived carbon

Abstract

The effect of oxidation upon the CO 2 capture performance has been studied taking a phenolic resin carbon as the base material. Oxygen surface groups were introduced through liquid and gas phase oxidation treatments, using ammonium persulfate, nitric acid and air, respectively.The surface chemistry of the final carbon is strongly affected by the type of oxidation treatment: liquid phase oxidation introduces a greater amount of oxygen, mostly as carboxylic groups; these are absent in the gas phase oxidised sample that contains mainly ether and carbonyl functionalities. The porous texture of the samples is also affected by the oxidation treatment: through liquid phase oxidation the pore volume is somewhat reduced, while this is slightly developed by air treatment at 693 K. Despite the reduction in the porous volume and the acidic surface, liquid-phase oxidised samples present greater CO 2 adsorption capacity than the starting carbon due to Lewis acid-base interactions with the CO 2 molecule.Moreover: oxidised samples are easily regenerated, and observed heats of adsorption are † Corresponding Author: Tel : +34 985 119090; E-mail address: frubiera@incar.csic.es. (F. Rubiera) 2 typical from physisorption processes, which will facilitate the adsorbent regeneration in cyclic adsorption processes. Oxidation is therefore proposed as a plausible modification technique for developing easy-to-regenerate carbon adsorbents with enhanced CO 2 capture performance.

Enhanced CO2/N2 selectivity in amidoxime-modified porous carbon

“…With this in mind, the CO 2 and N 2 adsorption capacities are given in Table 2. For the activated carbon, the CO 2 adsorption capacity was measured to be 2.87 mmol/g at 1 bar, 298 K and 4.970 mmol/g at 1 bar, 273 K. Though the CO 2 uptake values for activated carbon can vary extensively depending on the nature of the carbon and the exact activating parameters, the capacity values measured for the aC are comparable to other studies on activated carbon [7,14,22]. After AO grafting, the CO 2 capacities for both loadings were similar at $4.2 mmol g À1 for aC-AO1 and $4.3 mmol g À1 for aC-AO2, despite the differences in the surface area and AO grafting yields.…”

“…Though nitrogen functionality has been the most studied, other functional groups such as oxygen-containing ether and hydroxyl groups can also interact with CO 2 via electrostatic interactions leading to enhanced CO 2 adsorption capacity [13]. For example, Plaza et al investigated the impact of oxidation on the CO 2 capacity of phenolic resin carbon and observed an enhancement in uptake in the oxidized carbon as compared to the parent carbon [14].…”

Green coffee based CO2 adsorbent with high performance in postcombustion conditions

“…The CO 2 adsorption performance of a porous carbon is mainly governed by its pore size distribution and the operation conditions (temperature and pressure) [25,26]. However, the surface chemistry can also play a role: the presence of surface N and O donor groups can enhance the adsorbent-adsorbate interactions, favouring CO 2 selectivity and adsorption capacity [19,[56][57][58]. The inorganic matter naturally present in biomass-derived activated carbons, mainly K compounds, have also shown to present a positive effect on the adsorption of CO 2 [59].…”

Post-combustion CO2 adsorption on activated carbons with different textural properties

“…In this context, adsorption onto porous solids is an effective and versatile technique for the removal of different classes of pollutants from gaseous or liquid streams, thanks to the potentially high selectivity toward the target contaminant and its general low maintenance costs [8][9][10][11][12][13][14][15][16][17]. For CCS application, different classes of adsorbents, such as carbonaceous materials, zeolites, mesoporous silicas, metal organic frameworks, molecularly imprinted sorbents etc., are currently being investigated [8,13,16,[18][19][20][21][22]. Numerous literature studies are focused on solids functionalization with basic nitrogen groups (mainly organic amines), able to favourably interact with acidic CO 2 molecules [8,16,23].…”