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High Density and Super Ultra‐Microporous‐Activated Carbon Macrospheres with High Volumetric Capacity for CO 2 Capture
Author(s) -
Liu Jingjing,
Liu Xin,
Sun Yuan,
Sun Chenggong,
Liu Hao,
Stevens Lee A.,
Li Kaixi,
Snape Colin E.
Publication year - 2018
Publication title -
advanced sustainable systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.499
H-Index - 24
ISSN - 2366-7486
DOI - 10.1002/adsu.201700115
Subject(s) - potassium hydroxide , microporous material , adsorption , activated carbon , carbon fibers , volume (thermodynamics) , desorption , bar (unit) , materials science , potassium , specific surface area , chemical engineering , chemistry , analytical chemistry (journal) , catalysis , chromatography , organic chemistry , composite material , physics , composite number , meteorology , engineering , metallurgy , quantum mechanics
Activated carbon (AC) spheres with a diameter of 1.0–2.0 mm are synthesized from coal tar pitch for postcombustion carbon capture. The as‐prepared AC macrospheres after potassium hydroxide (KOH) activation are found to possess extraordinarily developed microporosity of which 87% is ultra‐microporosity with pore diameters less than 0.8 nm. Despite the relatively low surface area of just 714 m 2 g −1 with a pore volume of 0.285 cm 3 g −1 , the macrospherical carbon adsorbents achieve exceedingly high CO 2 uptake capacities of 3.15 and 1.86 mmol g −1 at 0 and 25 °C, respectively, with a CO 2 partial pressure of 0.15 bar. Cyclic lifetime performance testing demonstrates that the CO 2 uptake is fully reversible with fast adsorption and desorption kinetics. More importantly, due to their high bulk density of ≈1.0 g cm −3 , the AC macrospheres exhibit extremely high volumetric CO 2 uptakes of up to 81.8 g L −1 at 25 °C at 0.15 bar CO 2 , which represents the highest value ever reported for ACs. The high ultra‐microporosity coupled with the potassium‐modified physiochemical surface properties is found to be responsible for the outstanding CO 2 adsorption performance of the pitch‐based AC macrospheres.