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• A hierarchical CuCo LDH adsorbent combining the advantages of basic surface and highly dispersed metal active sites (Cu,Co) was developed for the deep removal of ppm-H 2 S from H 2. • The obtained LDH adsorbent endows effective elimination of trace H 2 S (50 ppmv) without additional hydration at room temperature, with superior dynamic adsorption capacity of 187 mg-H 2 S/g-ads. and high Henry's law selectivity toward H 2 S/CO 2 (exceeds 106). • The outstanding performance could be attributed to the highly exposure of metal hydroxide, where the surface basic hydroxide groups provide alkaline environment for the dissociation of H 2 S, and the highly dispersed metal active sites enable selective capture of dissociated H 2 S through reactive adsorption. Deep removal of ppm-H 2 S is critical for H 2 quality control due to the increasing demand for ultrahigh-purity H 2 in the up-and-coming fuel cell market. Herein, a CuCo layered double hydroxide (LDH) adsorbent with basic surface and high dispersion of active (Cu, Co) metal sites was developed for selective capture of ppm-H 2 S. The as-synthesized adsorbent enables effective elimination of H 2 S from 50 to <1 ppm with superior dynamic adsorption capacity of 187 mg-H 2 S/g-ads, which outperformed the reported benchmark adsorbents. The excellent performance could be attributed to the hollow structure and ultra-thin LDH nanosheets, which endow the high exposure of metal hydroxide sites, and thus facilitating the selective capture of H 2 S through reactive adsorption. For practical application, the effects of CO 2 and H 2 O on adsorption were also investigated. The excellent H 2 S adsorption performance demonstrated in this work makes hydroxide a promising adsorbent for removal of ppm-H 2 S for ultrahigh purity H 2 production. [ABSTRACT FROM AUTHOR]

• 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]

A novel microporous metal-organic framework dptz-CuGeF 6 was synthesized at room temperature and exhibited excellent performance for separation of CO 2 , CH 4 and N 2. [Display omitted] • A new MOF dptz-CuGeF 6 with ultra-microporous structure was synthesized at room temperature. • dptz-CuGeF 6 showed good stability against water vapor and some organic solvents. • Its CO 2 capacity at 15 kPa and 100 kPa reached as high as 2.17 mmol/g and 3.23 mmol/g at 298 K separately. • Its CO 2 /CH 4 and CO 2 /N 2 selectivity reached as high as 80 and 175.5, respectively. • Molecule simulation revealed that the fluorine groups are mainly responsible for its high selectivity of CO 2. Efficient capture of CO 2 from flue gas and removal of CO 2 from biomethane by physical adsorption are in great need. Herein, we report the facile synthesis of a new pillared-layer metal-organic frameworks, dptz-CuGeF 6 for CO 2 separation from the flue gas or the biomethane. The resulting samples were characterized. Structurally, the dptz-CuGeF 6 possess double-interpenetrated frameworks formed by two staggered, independent sql sheets, in which the cations Cu2+ are coordinated by four dptz ligands, making the dptz-CuGeF 6 exhibit narrow and uniform ultra-micropores of 5.25 Å. Its CO 2 capacity reached 2.17 mmol/g at 15 kPa and 3.23 mmol/g at 100 kPa separately, and its selectivity of CO 2 /CH 4 (50:50) and CO 2 /N 2 (15:85) reached as high as 80 and 175.5, respectively. The stability experiments demonstrated the intact structure of dptz-CuGeF 6 was retained after exposure in moisture air (RH = 50% or RH = 80%) as well as in several polar solvents. Breakthrough experiments confirmed that CO 2 /CH 4 or CO 2 /N 2 binary mixture were efficiently separated. Molecule simulation revealed that both F···C CO2 and multiple C-H···O CO2 interactions in the pores of dptz-CuGeF 6 played an important role in enhancing its selectivity of CO 2 adsorption. The dptz-CuGeF 6 would be promising for CO 2 capture and separation from flue gas or biomethane. [ABSTRACT FROM AUTHOR]

[Display omitted] • The PEI/S adsorbent outperforms multiple adsorbents with a superior dynamic adsorption uptake of 0.85 mmol-CO 2 /g-sorb at hundred-ppm concentration of CO 2 in the feed for H 2 purification. • The adsorption isotherms and kinetics of PEI/S can be well fitted with Langmuir–Freundlich and Avrami models. • The effects of adsorption temperature, PEI loading, co-existing H 2 O of PEI/S adsorbent on CO 2 adsorption were examined comprehensively. • An efficient TSA process using PEI/S was proposed with adsorption at 25℃ and desorption at 100℃ for hydrogen purification. Ultrahigh-purity hydrogen (6 N grade) suitable for hydrogen fuel cells requires the removal of CO 2 impurity from commercial hydrogen feed. In this study, CO 2 adsorption over a series of potential solid adsorbents was assessed at both high (0.1–1 bar) and low (hundreds of part-per-million) concentrations. With a distinct trend at higher concentrations (0.1–1 bar), PEI/S showed a remarkable CO 2 capacity of 0.86 mmol/g at concentration as low as hundred part-per-million and outperformed the other adsorbents. The impacts of polyethylenimine (PEI) loading, adsorption temperature, co-existing H 2 O, and regenerability were investigated systematically. Adsorption isotherms of PEI/S at various loadings were represented with the Langmuir–Freundlich model, while adsorption kinetics were simulated and fitted with the AFO model. The effectiveness of PEI/S for CO 2 removal was further investigated in dynamic fixed-bed breakthrough experiments. The co-presence of trace water vapor in the feed stream showed negligible inhibition on CO 2 adsorption. In addition, multiple cycles of adsorption–desorption tests demonstrated the excellent regenerability of the PEI/S adsorbents. This study gave a comprehensive evaluation and demonstration of supported polyethylenimine as a potential TSA adsorbent for adsorptive removal of trace CO 2 for ultrahigh purity H 2 production. [ABSTRACT FROM AUTHOR]