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• High-performance adsorbents with diamine-functionalized mesoporous support (P/D-SD) effectively remove trace CO 2 from C 2 H 2. • P/D-SD shows high CO 2 adsorption capacity (1.76 mmol/g at 298 K and 0.0004 bar) and CO 2 /C 2 H 2 IAST selectivity surpassing 105. • P/D-SD produces highly pure C 2 H 2 (>99.9 %) from CO 2 /C 2 H 2 mixtures, with adsorption performance unaffected by moisture. • P/D-SD shows fast CO 2 adsorption kinetics and excellent cycling stability. The removal of trace carbon dioxide (CO 2) from acetylene (C 2 H 2) through adsorption poses a significant challenge due to their similar kinetic diameters and physical properties. Here, we report a novel solid amine adsorbent, polyethyleneimine-diethanolamine functionalized silica dioxide (termed P/D-SD), which exhibited a remarkable CO 2 adsorption capacity of 1.76 mmol/g at 298 K and 0.0004 bar. The IAST selectivity of the CO 2 /C 2 H 2 (1/99, v/v) mixture of P/D-SD was 7.98E + 05. The exceptional separation performance of P/D-SD is demonstrated through breakthrough experiments, producing ultra-high purity C 2 H 2 (greater than 99.9 %) from CO 2 /C 2 H 2 (1/99) mixtures. Its CO 2 adsorption performance remains largely unaffected under different humidity condition. Furthermore, P/D-SD exhibited excellent stability in the adsorption–desorption cycle and rapid CO 2 adsorption kinetics at different temperatures when compared with P-SD. The adsorption mechanism of P/D-SD with CO 2 was studied as a chemisorption process via in situ DRIFTS. [ABSTRACT FROM AUTHOR]

Monolithic binder-free CO 2 adsorbents with high adsorption capacity, selectivity, adsorption-desorption kinetics, and regenerability are highly desired to both reduce the environmental impact of anthropogenic CO 2 emissions and purify valuable gases from CO 2. Herein, we report a strategy to prepare monolithic carbonaceous CO 2 adsorbents from low-cost and underutilized bioresources, which enabled the formation of a delicate anisotropic, hierarchical porous structure. With optimized material composition and processing conditions, the biobased carbon adsorbent demonstrated a CO 2 adsorption capacity of 4.49 mmol g-1 at 298 K and 100 kPa, relatively weak adsorbent-adsorbate affinity, good CO 2 /N 2 selectivity, and advantageous hydrophobicity against water vapor. Moreover, the unique anisotropic porous structure provided high stiffness and good flexibility to the adsorbent in the axial and radial directions, respectively. We confirmed that this type of carbon adsorbent could be packed in a column for dynamic CO 2 capture independent of any binders, indicating its promising future for further development toward widespread utilization. [Display omitted] • Biocarbon aerogels with anisotropic, hierarchical porous structure were prepared. • Carbon aerogels reached CO 2 adsorption capacity of 4.49 mmol g−1 (298 K, 100 kPa). • Carbon aerogels showed good CO 2 /N 2 selectivity and low water vapor adsorption. • Carbon aerogels exhibited strong and unique anisotropic mechanical properties. • Carbon aerogels were packed in a column without binders for large-scale CO 2 capture. [ABSTRACT FROM AUTHOR]

In the present work, a biosynthesis route for the preparation of hierarchical pompon-like SAPO-34 was developed. Commercially available bacterial cellulose aerogel was used as template. SiO 2 loaded bacterial cellulose aerogel was used as silica source and a simple hydrothermal treatment was used for crystallization. XRD, FT-IR, SEM, TEM, N 2 adsorption-desorption and TG techniques were employed to characterize the obtained samples. The hierarchical pompon-like SAPO-34 showed a spherical morphology that was comprised of nanosheets with a thickness less than 30 nm. The specific surface area of the hierarchical pompon-like SAPO-34 was 498 m2/g that was higher than the trigonal SAPO-34 crystals of 465 m2/g. The ultrasonic treatment experiment indicated a high stability of the pompon-like structure. In addition, the hierarchical pompon-like SAPO-34 exhibited a CO 2 adsorption capacity of 2.26 mmol/g at 100 kPa and 298K and the corresponding CO 2 /CH 4 ideal separation factor was 5.7, which was higher than that of trigonal SAPO-34 crystals. The saturated adsorption capacity and b-value were estimated using single site Langmuir, Toth and Sips adsorption isotherm models and the observed results were constant. Compared with trigonal SAPO-34, hierarchical pompon-like SAPO-34 displayed a higher saturated adsorption capacity, but a lower b-value. [Display omitted] • A biosynthesis route was developed for the synthesis of hierarchical SAPO-34. • Economical bacterial cellulose aerogel was used as the template. • The hierarchical SAPO-34 crystals were comprised of ultrathin zeolite nanosheets. • A higher surface area and a higher CO 2 adsorption capacity were observed. [ABSTRACT FROM AUTHOR]