CO2 Capture in the Sustainable Wheat-Derived Activated Microporous Carbon Compartments

Abstract

Microporous carbon compartments (MCCs) were developed via controlled carbonization of wheat flour producing large cavities that allow CO2 gas molecules to access micropores and adsorb effectively. KOH activation of MCCs was conducted at 700 °C with varying mass ratios of KOH/C ranging from 1 to 5, and the effects of activation conditions on the prepared carbon materials in terms of the characteristics and behavior of CO2 adsorption were investigated. Textural properties, such as specific surface area and total pore volume, linearly increased with the KOH/C ratio, attributed to the development of pores and enlargement of pores within carbon. The highest CO2 adsorption capacities of 5.70 mol kg−1 at 0 °C and 3.48 mol kg−1 at 25 °C were obtained for MCC activated with a KOH/C ratio of 3 (MCC-K3). In addition, CO2 adsorption uptake was significantly dependent on the volume of narrow micropores with a pore size of less than 0.8 nm rather than the volume of larger pores or surface area. MCC-K3 also exhibited excellent cyclic stability, facile regeneration, and rapid adsorption kinetics. As compared to the pseudo-first-order model, the pseudo-second-order kinetic model described the experimental adsorption data methodically.

CO2 adsorption in hydrochar produced from waste biomass

“…Adsorption in porous solids has been proposed as a viable alternative for the treatment of the flue gas [17][18][19]. However, in order to improve the efficiency of the adsorption process, the adsorbent should have not only a high adsorption capacity, but also a high selectivity [20] in addition to being easily regenerated [21].…”

Dry and Wet CO2 Capture from Milk‐Derived Microporous Carbons with Tuned Hydrophobicity

“…[ 31d,33 ] Both in dry and in wet environments, carbon micropores are known to be more effective in capturing CO 2 than carbon mesopores. [ 14,15b,20 ] To simultaneously achieve high micropore pore volume and sufficient nitrogen content, the activation temperature for MDCs was kept much lower than normally employed, i.e., 600 °C versus 1000 °C or higher. This achieved the dual goal of obtaining high micropore volume at the expense of mesopores, while retaining sufficient surface nitrogen content for enhanced CO 2 binding.…”

“…Activated carbons are attractive for CO 2 capture due to their low‐cost and overall abundance, in particular when derived from biomass‐based precursors, or from coal and oil products. Carbons derived from pyrolysis and activation of yeast, [ 12 ] fungi, [ 13 ] palm shells, [ 14 ] coconut shells, [ 15 ] pine nut shells, [ 16 ] soya bean dregs, [ 17,18 ] bamboo, [ 19 ] wheat flour, [ 20 ] and leaves [ 21 ] have been employed for carbon capture. [ 22 ] Carbons prepared from such waste precursors stand out as economically promising and sustainable, but generally fall short of meeting the CO 2 capture performance metrics set by the more complex and expensive systems such as MOFs.…”

Enhanced uptake capacities and isosteric heats of CO2and CH4adsorption onspent coffee ground activated carbons loaded with metal ions

“…The first weight loss stage is attributed to physisorbed water and gases. 20 The significant weight losses observed are associated with the decomposition of hydroxyl, carboxylic, and other surface functional groups at the second weight loss stage from ∼200 to 500 • C. 21 Figure 1b shows the TGA analysis for GCAC/600 and Fe-GCAC/600 samples. Up to ∼100 • C, both samples exhibited a weight loss of ∼10 wt.% and, up to ∼500 • C, there were no significant weight changes.…”