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[Display omitted] • Leaching of the valuable metals and utilizing carbon residue from spent lithium-ion batteries. • K 2 CO 3 impregnated carbon utilized as an adsorbent for indoor CO 2 capture. • An investigation of the reaction mechanism for CO 2 adsorption on supported K 2 CO 3 under humid condition. • At low CO 2 concentrations, the CO 2 adsorption capacity for K 2 CO 3 /carbon ranged from 5.1 to 7.3 wt% Recycling and reusing the carbon-residues (i.e., graphite), as well as recovering valuable metals by leaching from spent lithium-ion batteries, is environmentally and economically significant. In particular, since a large amount of spent lithium-ion batteries (LIBs) will be generated along with the rapid growth of electric vehicles (EVs), research on recycling carbon-residues from LIB anodes is urgently needed. Herein, the battery powder (BP) was obtained from spent lithium-ion batteries (LIBs) through physical-pyrolysis and sieving. Chemical composition analysis confirmed that the battery used in this work was composed of NCM cathode with high-nickel content and graphite anode material. The average particle size of the obtained BP was 87 μm. In order to obtain the residue having high concentration of carbon, the metal extraction was applied using an HCl solution. As a result, metals (Li, Ni, Co, Mn, Al, Cu, and Fe) in the final remnant were found to be less than 2%, and carbon was found to have a purity of 97% or more. The obtained BP was tested as both the adsorbent and support for indoor CO 2 capture. Various activation treatments were examined to enhance the textural properties of BP. BP-K (K 2 CO 2 impregnated BP) adsorbents were prepared, and their CO 2 adsorption performances were evaluated with CO 2 adsorption isotherms, thermogravimetric analysis (TGA), and 0.1 m 3 chamber (CO 2 IR analyzer) at low CO 2 level (1000–2000 ppm). Through XRD and FT-IR analyses, the adsorption mechanism between K 2 CO 3 and CO 2 under moisture-containing indoor air conditions was confirmed to depend on chemisorption in the following reaction pathway: R1–R3(K 2 CO 3 (s) + H 2 O (g) + CO 2 (g) ⇋ 2KHCO 3 (s) (R1), K 2 CO 3 (s) + 1·.5H 2 O(g) ⇋ K 2 CO 3 ·1·.5H 2 O(s) (R2), K 2 CO 3 ·1·.5H 2 O(s) + CO 2 (g) ⇋ 2KHCO 3 (s) + 0·.5H 2 O(g)(R3)). The adsorption working capacities of the recycled BP-K adsorbents were remained relatively constant during four consecutive cycles. [ABSTRACT FROM AUTHOR]

Size-controlled hybrid ZIFs (core-shell ZIF-67@ZIF-8, ZIF-8@ZIF-67, and bimetallic Zn/Co-ZIF-8) with the same particle size were synthesized by a seed-mediated methodology by adjusting the particle size of core ZIFs. The synthesized hybrid ZIFs was tested as heterogeneous catalysts for the CO 2 cycloaddition to epoxides using pure CO 2 gas and mixed gas (85 % CO 2 /15% N 2) without any co-catalyst and solvent. The effect of the composition of shell and core ZIFs on the catalytic performance of CO 2 cycloaddition reaction to epoxides were investigated. Furthermore, the correlation between structural defects and catalytic activity in ZIF catalysts along with their particle sizes was investigated by calculating the ratio of DXRD/DSEM. Both core-shell type ZIF-67@ZIF-8 and ZIF-8@ZIF-67 exhibited better catalyst performance of CO 2 cycloaddition reaction than other ZIF catalysts. Among the ZIF catalysts, ZIF-67@ZIF-8 exhibited the highest catalytic performance for epoxide conversion owing to its abundant Lewis acid-base properties and relatively large window size of ZIF-8 shell with appropriate binding force between epoxide and CO 2. It showed good recyclability for CO 2 cycloaddition reaction without a structural collapse during ten recycles. The structural stability of ZIF-67@ZIF-8 was examined in detail by a hot filtering test, leaching test, and TGA analysis. The mechanism of CO 2 cycloaddition reaction was proposed and the effect of the shell composition in core-shell type ZIFs on the binding energy with epoxide substrate also was studied based on DFT calculations. [Display omitted] • Synthesis of size-controlled core-shell ZIFs by a seed-mediated methodology. • Investigating the effect of the core-shell ZIF structures on the catalytic activity. • ZIF-67@ZIF-8 exhibits high catalytic activity for CO 2 cycloaddition reaction. • The correlation between structural defects and catalytic activity in ZIF catalysts. • Calculation of binding energy with epoxide and core-shell ZIFs using DFT method. [ABSTRACT FROM AUTHOR]

[Display omitted] • KOH was impregnated on rice husk KOH-activated carbon, named as DKOH-AC. • DKOH-AC involved both chemi- and physi-sorption when KOH-AC allowed physi-sorption. • CO 2 adsorption on DKOH-AC followed Freundlich and pseudo second order models. • DKOH-AC adsorbed 2.1 mmol/g in an indoor condition. Relatively high indoor CO 2 concentration (greater than 1000 ppm) has a negative impact on human health. In this work, a cost-effective CO 2 adsorbent (DKOH-AC) was developed by impregnating KOH on rice husk-based KOH activated carbon (KOH-AC, 1439 m2/g). KOH can be successfully loaded on the surface of KOH-AC and significantly changed its surface properties. DKOH-AC still remained a considerable surface area (206 m2/g) and showed a similar S micro /S BET ratio. In-situ FTIR analysis confirmed that the major CO 2 adsorption mechanism of KOH-AC was based on physisorption while that on DKOH-AC involved both chemisorption and physisorption. DKOH-AC showed a higher heat of adsorption (34 ∼ 41 KJ/mol) and gas selectivity (16.6) than these of KOH-AC. KOH-AC quickly reached an adsorption equilibrium (about 50 min) as compared to that of DKOH-AC. In addition, DKOH-AC exhibited an excellent adsorption performance of 2.1 mmol/g for a low concentration of CO 2 (2000 ppm ∼ 500 ppm) under indoor conditions. Both the CO 2 adsorption isotherm on KOH-AC and DKOH-AC well followed the Langmuir and Freundlich models. The CO 2 adsorption kinetics on KOH-AC followed the pseudo-first order model whereas that on DKOH-AC obeyed the pseudo-second order model. The adsorption process was controlled by the intraparticle diffusion combined with the film diffusion model. [ABSTRACT FROM AUTHOR]

Synthesis of a zirconium-benzenedicarboxylate, UiO-66, was carried out in increasing production scales of 250 mL, 1 L and 5 L at 393 K. Investigation on the effect of synthesis parameters on the product yield and textural properties was carried out using autoclaves of 250 mL capacity, whereas systematic scale up works were conducted using glass reactors fitted with condensers under ambient pressure conditions. Finally, 100 L pilot scale synthesis of UiO-66 was carried out using commercial terephthalic acid as ligand with industrial-grade dimethylformamide solvent. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and N 2 adsorption–desorption measurements. The pelletized UiO-66 using polyvinyl alcohol as a binder demonstrated excellent CO 2 /N 2 separation (36:1) with moderately high CO 2 adsorption capacity (191 mg/g) at 20 bar room temperature conditions. UiO-66 also showed excellent catalytic activity in cycloaddition of CO 2 to styrene oxide at 2.0 MPa and 373 K with close to 100% selectivity to carbonate. No appreciable particle size effect on the catalytic activity was observed, and UiO-66 could be reused 3 times without loss of catalytic activity. [ABSTRACT FROM AUTHOR]

The article talks about an experiment to examine the cycloaddition of Carbon Dioxide (CO2) to propylene epoxide over Metal-organic frameworks (MOFs) which are crystalline organic-inorganic hybrid structures formed by metal ions, with a quaternary ammonium salt as a co-catalyst. It adds that CO2 is a major greenhouse gas and chemical conversion of CO2 by cycloaddition reaction is a way of sequestration.

[Display omitted] • The working capacity and stability of absorbent were studied for CO 2 capture. • MPS-supported epoxide-functionalization of PEHA absorbent was synthesized. • PO-PEHA/MPS adsorbent exhibited the working capacity of 1.8 mmol g−1 in 20 cycle. • When the adsorption time was reduced, the regeneration heat was 2.86 GJ tCO 2 -1. • Adsorbent that is regenerated in 100% CO 2 , not inert (N 2 , He) conditions was developed. N -functionalized solid adsorbents have been studied for post-combustion CO 2 capture. Most studies have focused only on the adsorption condition of the adsorbents. Few studies have focused on the regeneration condition of adsorbents. Regeneration is required under the condition of 100 % CO 2 for high-purity CO 2 separation. Regeneration under inert conditions such as N 2 or He, not under the condition of 100 % CO 2 regeneration are required additional cost for high-purity CO 2 separation. In this study, a macroporous silica (MPS) support, which combined a high surface area, large porosity and large pore volume, was selected as the support to achieve high CO 2 capture performance. Pentaethylenehexamine (PEHA) was selected because of its high amine content, high adsorption capacity, high thermal stability, and low cost. The epoxide functionalization of PEHA was used to suppress the urea formation under regeneration conditions. The working capacity and cyclic stability of epoxide functionalization of MPS-based PEHA adsorbents were investigated. A working capacity of 1.8 mmol g−1 was maintained by repeating adsorption and desorption experiments 20 times under an adsorption condition of 15 % CO 2 and a desorption condition of 100 % CO 2. Additionally, the stability of the adsorbent under a 100 % CO 2 regeneration condition was confirmed by maintaining the working capacity constant during 20 repeated adsorption and desorption cycle experiments. When the adsorption time was reduced to minimize H 2 O adsorption, the regeneration heat of the adsorbent was 2.86 GJ tCO 2 -1. These results demonstrated that the regeneration ability was excellent under the condition of 100 % CO 2 , which is the actual process application condition. This approach is promising for industrial applications of CO 2 capture technology. [ABSTRACT FROM AUTHOR]