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Direct separation of high purity ethylene (C2H4) from an ethane (C2H6)/ethylene mixture is a critical and challenging task owing to the very similar molecular size and physical properties of the two components. While some studies have attempted this separation, there is a lack of excellent porous materials with strong binding affinity for C2H6-selective adsorption via an energy-efficient adsorptive separation process. Herein, we report a titanium metal-organic framework with strong binding affinity and excellent stability for the highly efficient removal of C2H6 from C2H6/C2H4 mixtures. Single component adsorption isotherms demonstrated a larger amount of adsorbed ethane (1.16 mmol·g−1 under 1 kPa) and high C2H6/C2H4 selectivity (2.7) for equimolar C2H6/C2H4 mixtures, especially in the low-pressure range, which is further confirmed by the results of grand canonical Monte Carlo simulations for C2H6 adsorption in this framework. The experimental breakthrough curves showed that C2H4 with a high purity was collected directly from both 1:9 and 1:15 C2H6/C2H4 (volume ratio) mixtures at 298 K and 100 kPa. Moreover, the unchanged adsorption and separation performance after cycling experiments confirmed the promising applicability of this material in future.

The separation of ethylene and ethane is a crucial, challenging and cost-intensive process in chemical engineering. Metal–organic frameworks (MOFs) are a class of novel porous adsorbents used for the separation of ethylene/ethane mixtures. However, MOFs are normally crystalline powders that cause multiple problems, such as dust, abrasion and heat/mass loss, as well as significant pressure drops on the adsorption bed resulting in a sudden stop in production. To solve these issues, we have prepared four different sphere-shaped adsorbents, including Mg-gallate, Co-gallate, MUV-10(Mn) and MIL-53(Al) using a calcium alginate method to achieve excellent ethylene/ethane separation performance. The performance of the sphere-shaped adsorbents has been validated using mechanical strength measurements, powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, gas adsorption isotherms and dynamic breakthrough experiments. The excellent mechanical strength of these sphere-shaped adsorbents meets the criteria for industrial application in gas separation. Thus, the energy consumption and operating cost will be further reduced in the ethylene production process. We believe that this shaping method will open a prosperous route to the development of MOFs toward higher technology levels and their commercial application.

A highly stable Hofmann-based metal−organic framework has been purposely synthesized for efficient C3H6/C3H8 separation through the linker modification strategy using direct mixing method under ambient conditions.

Adsorptive separation of propylene/propane (C 3 H 6 /C 3 H 8 ) mixture is highly desired for its potential energy saving on replacing currently deployed and energy-intensive cryogenic distillation technique. Realizing efficient C 3 H 6 /C 3 H 8 separation in the emerging hydrogen-bonded organic frameworks (HOFs) is very challenging and has been rarely reported due to the lack of functional sites for preferential gas binding. By virtue of crystal engineering, we herein report a rare example of functionalized HOF (termed as HOF-16 ) with free -COOH sites for the efficient separation of C 3 H 6 /C 3 H 8 mixtures. Under ambient conditions, HOF-16 shows a significant C 3 H 6 /C 3 H 8 uptake difference (by 76%) and selectivity (5.4) in contrast to those of other carboxylic acid-based HOFs. Modeling studies indicate that free -COOH groups together with the suitable pore confinement facilitate the recognition and high-density packing of gas molecules. The separation performance of HOF-16 has also been validated by breakthrough experiments. HOF-16 is stable in harsh condition including strong acidity and water.

The flue gas from fossil fuel power plants is a long-term stable and concentrated emission source of CO

Functional nanoporous materials are widely explored for CO2 separation, in particular, small-pore aluminosilicate zeolites having a “trapdoor” effect. Such an effect allows the specific adsorbate to push away the sited cations inside the window followed by exclusive admission to the zeolite pores, which is more advantageous for highly selective CO2 separation. Herein, we demonstrated that the protonated organic structure-directing agent in the small-pore silicoaluminophosphate (SAPO) RHO zeolite can be directly exchanged with Na+, K+, or Cs+ and that the Na+ form of SAPO-RHO exhibited unprecedented separation for CO2/CH4, superior to all of the nanoporous materials reported to date. Rietveld refinement revealed that Na+ is sited in the center of the single eight-membered ring (s8r), while K+ and Cs+ are sited in the center of the double 8-rings (d8rs). Theoretical calculations showed that the interaction between Na+ and the s8r in SAPO-RHO was stronger than that in aluminosilicate RHO, giving an enhanced “trapdoor” effect and record high selectivity for CO2 with the separation factor of 2196 for CO2/CH4 (0.02/0.98 bar). The separation factor of Na-SAPO-RHO for CO2/N2 was 196, which was the top level among zeolitic materials. This work opens a new avenue for gas separation by using diverse silicoaluminophosphate zeolites in terms of the cation-tailored “trapdoor” effect.

The separation of ethylene (C2H4) from C2 hydrocarbons is considered as one of the most difficult and important processes in the petrochemical industry. Heat-driven cryogenic distillation is still widely used in the C2 hydrocarbons separation realms, which is an energy intensive process and takes up immense space. In response to a greener, more energy-efficient sustainable development, we successfully synthesized a multifunction microporous Mg-based MOF [Mg2(TCPE)(µ2-OH2)(DMA)2].solvents (NUM-9) with C2H6/C2H2 selectivity based on a physical adsorption mechanism, and with outstanding stability; especially, it is stable up to 500 °C under an air atmosphere. NUM-9a (activated NUM-9) shows good performances in the separation of C2H6/C2H2 from raw ethylene gases. In addition, its actual separation potential is also examined by LAST and dynamic column breakthrough experiments. GCMC calculation results indicate that the unique structure of NUM-9a is primarily conducive to the selective adsorption of C2H6 and C2H2. More importantly, compared with C2H4, NUM-9a prefers to selectively adsorb C2H6 and C2H2 simultaneously, which makes NUM-9a as a sorbent have the capacity to separate C2H4 from C2 hydrocarbon mixtures under mild conditions through a greener and energy-efficient separation strategy.

The development of porous metal–organic framework (MOF) solids displaying efficient separation and purification of acetylene is of cardinal significance but challenging in the chemical industry. Am...

Methane (CH

BACKGROUND: Effective cellulose hydrolysis has a huge potential for producing high value‐added biomass‐based platform chemicals, such as glucose, hydroxymethylfurfural, levulinic acid, and total reducing sugars (TRS). Particularly, a magnetic multifunctional solid acid catalyst (Fe₃O₄/Cl–MCMB–SO₃H) was synthesized by loading the active groups on the magnetic mesocarbon microbead (MCMB) derived from the co‐calcination of coal tar pitch and ferroferric oxide, which was applied as a catalyst in the conversion of cellulose into TRS. RESULTS: Given the superior properties of MCMB, a novel magnetic MCMB‐based solid acid with cellulose‐binding domain (–Cl group) and catalytic domain (–SO₃H group) was successfully prepared. Results indicated that this catalyst exhibited superior catalytic activity, recyclability and regenerability, and easy separation from the reactant. The acidic densities of –SO₃H and –Cl in Fe₃O₄/Cl–MCMB–SO₃H reached 1.77 and 1.32 mmol/g, respectively. The 68.6% TRS yield can be obtained from cellulose at 140 °C for 3 h in distilled water by using Fe₃O₄/Cl‐MCMB‐SO₃H as the catalyst. The TRS yield still reached 61.1% after the catalyst was used six times. Importantly, through catalyst regeneration, the –SO₃H density and TRS yield still reached 1.69 mmol/g and 67.3%, indicating that the catalyst exhibited excellent regenerability. CONCLUSION: Such multifunctional magnetic catalyst would be a promising catalyst in the conversion of cellulose into biofuels, which was attributed to the efficient catalytic performance, magnetism, and excellent recyclability and regenerability. © 2019 Society of Chemical Industry

Functional nanoporous materials are widely explored for CO2 separation, in particular, small-pore aluminosilicate zeolites having a “trapdoor” effect. Such an effect allows the specific adsorbate to push away the sited cations inside the window followed by exclusive admission to the zeolite pores, which is more advantageous for highly selective CO2 separation. Herein, we demonstrated that the protonated organic structure-directing agent in the small-pore silicoaluminophosphate (SAPO) RHO zeolite can be directly exchanged with Na+, K+, or Cs+ and that the Na+ form of SAPO-RHO exhibited unprecedented separation for CO2/CH4, superior to all of the nanoporous materials reported to date. Rietveld refinement revealed that Na+ is sited in the center of the single eight-membered ring (s8r), while K+ and Cs+ are sited in the center of the double 8-rings (d8rs). Theoretical calculations showed that the interaction between Na+ and the s8r in SAPO-RHO was stronger than that in aluminosilicate RHO, giving an enhanced “trapdoor” effect and record high selectivity for CO2 with the separation factor of 2196 for CO2/CH4 (0.02/0.98 bar). The separation factor of Na-SAPO-RHO for CO2/N2 was 196, which was the top level among zeolitic materials. This work opens a new avenue for gas separation by using diverse silicoaluminophosphate zeolites in terms of the cation-tailored “trapdoor” effect., The sodium form of silicoaluminophosphate RHO zeolite exhibits a pronounced cation-tailored “trapdoor” effect, showing an unprecedented selectivity adsorption separation performance for CO2/CH4 and CO2/N2.

NH3 is the most important gaseous alkaline pollutant, which when accumulated at high concentrations can have a serious impact on animal and human health. More importantly, NH3 emissions will react ...

The slight differences between ternary components of C2 hydrocarbons make the separation of C2H2/C2H6/C2H4 mixtures one of the most challenging tasks in the petrochemical industry. In this study, a family of saturated coordination titanium-based metal–organic frameworks with high stability is constructed for one-step C2H4 purification. Single component adsorption measurements along with dynamic breakthrough experiments illustrated that these MOFs clearly exhibited large adsorption for C2H2 and C2H6 compared to C2H4, and could efficiently extract low concentrations of C2H6 and C2H2 from ternary C2H2/C2H6/C2H4 mixtures simultaneously. Grand canonical Monte Carlo simulations revealed the stronger affinity of the MOFs toward C2H6 and C2H2 compared to C2H4. Furthermore, the mostly intact structure of these MOFs after various examinations revealed their distinctive stability. The reasonably high C2H6 and C2H2 adsorption capacity, ultrahigh structural stability, and excellent separation performance rendered these materials good candidates for C2H4 purification from C2H2/C2H6/C2H4 mixtures in industry.