Activated Carbons Prepared from a Broad Range of Residual Agricultural Biomasses Tested for Xylene Abatement in the Gas Phase

Abstract

The environmental problems in Peru are rooted in the waste management of the residual agricultural biomass. Via our cooperative international research, nine different agricultural wastes from Peru were used as renewable sources to produce activated carbons that were tested in gas-phase xylene adsorption. The special properties of agro-waste activated carbons are the very large mesopore surface area, the narrow pore size distribution within the microporous–mesoporous region, and the slightly acidic character in the presence of oxygen-containing surface groups. The textural, structural, and surface properties of nine agro-waste activated carbons were correlated with their adsorption capacities in xylene adsorption and compared with those of a commercial activated carbon made of black coal. Adsorption capacities of agro-waste activated carbons were in the range of 371–115 mgxylene/gAC, whereas the adsorption capacity was 214 mgxylene/gAC for black coal-activated carbon. Higher adsorption capacities of ACs can be assigned to the synergism of their textural properties (larger mesopore surface area and larger micropore volume related to total pore volume) and their surface properties (lower content of surface oxygen functional groups related to their less acidic character and higher π–π* transitions in aromatic rings resulting in fewer defects within the graphitic structure).

Insight into the significant roles of microstructures and functional groups on carbonaceous surfaces for acetone adsorption

“…31 Great efforts have been made to correlate physico-chemical properties and adsorption capacities of VOCs such as toluene, xylene and alkyl halides. [32][33][34] Other than aforementioned VOCs, acetone is a typical strong polar VOC, which may exhibit different adsorption property to nonpolar or weak polar ones. Previous research regarding carbon-based acetone adsorption mainly focused on the micro or molecular mechanism.…”

Adsorption of volatile organic compounds on peanut shell activated carbon

“…Kawasaki et al also found the saturation capacities of toluene and p‐xylene on commercial AC were around 5.3 and 3.3 mmol/g, respectively . Cruz et al found that the adsorption of xylene (63 % p‐xylene, 29 % m‐xylene, and 8 % o‐xylene) on different agricultural residue activated carbons were within the range of 1.1–3.5 mmol/g, while commercial black coal‐activated carbon was around 2 mmol/g …”

Graphitic nitrogen in carbon catalysts is important for the reduction of nitrite as revealed by naturally abundant15N NMR spectroscopy

“…When fabricating carbon materials with tailored functionalities, the structure-property relationship at the atomic level should be considered. [1][2][3][4][5][6][7][8] These considerations are important for the synthesis of metal-free and carbon-based catalysts, where the activity stems from the enhanced exposure of the structural features being catalytically most active. [9][10][11][12][13][14][15][16][17] The absence of metal-containing entities has intensified the consideration of metal-free carbon catalysts as "green" catalysts.…”