(614j) Hydrophobic N-doped Biocarbon with High Adsorption Selectivity and Capacity for Benzene Series VOCs under Humid Conditions and Ultralow Pressures

N-doped microporous graphitized biocarbons (N-PCs) derived from dopamine were fabricated for competitive and selective adsorption towards benzene series Volatile Organic Compounds (VOCs) under humid conditions. A unique combination of large surface area ((>2080 m²/g), narrow pore distribution (6.8-8.8 Ã…), high amount of sp² C/N endow them with high adsorption capacity for benzene series VOCs, which is ∼3-5 times higher than those on zeolites and some metalorganic framework (MOF) adsorbents (i.e., MIL-101, HKUST-1, and UIO-66) at 80 Pa. Moreover, the N-PCs possesses enhanced hydrophobic character with higher amount of sp² C/N than some known activated carbons, and thus leads to their preferential adsorption for benzene series VOCs over H₂O. Temperature programmed desorption (TPD) and inverse gas chromatography (IGC) results showed that the surface of N-PCs exhibited much higher special interaction towards weakly polar VOCs but lower interaction with H₂O. Breakthrough experiments of p-xylene/water mixture depicted that the hydrogen treated HN-PC samples retained a very high working capacity of p-xylene (>5.1 mmol/g) at 80% relative humidity. This value was approximately 1-3 times greater than that of some activated carbon and MOF materials. Therefore, the high adsorption selectivity and capacity for VOCs under humid air make N-PCs a promising candidate for environmental air pollution control.

Keywords: N-doped microporous carbon; Adsorption equilibrium/kinetics; Competitive adsorption; Breakthrough curves; Humidity resistance