Selective Adsorption of Ethane over Ethylene in PCN-245: Impacts of Interpenetrated Adsorbent

Abstract

The separation of ethane from ethylene using cryogenic distillation is an energy-intensive process in the industry. With lower energetic consumption, the adsorption technology provides the opportunities for developing the industry with economic sustainability. We report an iron-based metal-organic framework PCN-245 with interpenetrated structures as an ethane-selective adsorbent for ethylene/ethane separation. The material maintains stability up to 625 K, even after exposure to 80% humid atmosphere for 20 days. Adsorptive separation experiments on PCN-245 at 100 kPa and 298 K indicated that ethane and ethylene uptakes of PCN-245 were 3.27 and 2.39 mmol, respectively, and the selectivity of ethane over ethylene was up to 1.9. Metropolis Monte Carlo calculations suggested that the interpenetrated structure of PCN-245 created greater interaction affinity for ethane than ethylene through the crossing organic linkers, which is consistent with the experimental results. This work highlights the potential application of adsorbents with the interpenetrated structure for ethane separation from ethylene.

Moisture stability of ethane‐selective Ni(II), Fe(III), Zr(IV)‐based metal–organic frameworks

“…Among different temperatures, the adsorption uptakes of ethane always exceed those of ethylene, reflecting ethane‐selective adsorption behavior of Zr‐bptc. At ambient pressure, ethane and ethylene uptakes in Zr‐bptc are 3.72 and 3.50 mmol/g at 288 K, 3.26 and 3.08 mmol/g at 298 K, 2.74 and 2.54 mmol/g at 308 K. The ethane uptake of Zr‐bptc (3.26 mmol/g) at 298 K and 100 kPa is superior to many reported ethane‐selective adsorbents (Table S3), such as activated carbon (2.52 mmol/g), ZIF‐8 (2.50 mmol/g), ZIF‐69 (2.20 mmol/g), ZIF‐4 (2.30 mmol/g), MAF‐49 (1.56 mmol/g), UiO‐66 (2.28 mmol/g) (Figure S11), Cu(ina) 2 (1.99 mmol/g), Cu(Qc) 2 (1.85 mmol/g), and Fe 2 (O 2 )(dobdc) (3.03 mmol/g), but the ethane uptake of Zr‐bptc is inferior to PCN‐245 (3.27 mmol/g) (Figure S12), IRMOF‐8 (4.00 mmol/g), and Ni(bdc)(ted) 0.5 (5.0 mmol/g) (Figure S13). …”

“…The mass loss of 32.1% for H 4 bptc is close to the theoretical value (32.4%) calculated from the formula Zr 6 O 4 (OH) 4 (bptc) 3 . Therefore, Zr‐bptc is thermally stable to 702 K. The thermal decomposition temperature of Zr‐bptc (702 K) outperformed most reported ethane‐selective MOFs, such as IRMOF‐8 (673 K), PCN‐250 (673 K), PCN‐245 (625 K), Ni(bdc)(ted) 0.5 (673 K), ZIF‐69 (643 K), and MIL‐142A (573 K), but slight lower than UiO‐66 (739 K) . The high thermal stability of Zr‐bptc and UiO‐66 probably lies on the strong Zr‐O coordination bonds and the 12‐connected Zr 6 (μ 3 ‐O) 4 (μ 3 ‐OH) 4 (COO) 12 SBU of Zr‐bptc and UiO‐66.…”

“…UiO‐66, PCN‐245, Ni(bdc)(ted) 0.5 exhibit the BET surface area of 790.8, 1,743.0, and 1,070.8 m 2 /g (Table S2), respectively. Their pore sizes predominantly center at ~0.6 nm for UiO‐66, ~1 nm for PCN‐245, and ~0.79 nm for Ni(bdc)(ted) 0.5 , respectively.…”

Alternatives to Cryogenic Distillation: Advanced Porous Materials in Adsorptive Light Olefin/Paraffin Separations

“…Similarly, Chen et al reported another iron MOF MIL‐142A with ethane adsorption selectivity (5.8–1.5 in the pressure range of 0–100 kPa) based on the ligand combination of terephthalate and 1,3,5‐tris(4‐carboxyphenyl)benzene . Recently, Lv et al reported an interpenetrated iron MOF PCN‐245 for ethane/ethylene separation . Metropolis MC calculations suggested that the interpenetrated structure of PCN‐245 creates greater interaction affinity for ethane than ethylene through the crossing organic linkers, which could account for the higher uptake of ethane and ethane/ethylene separation in the adsorption column containing PCN‐245.…”

“…[131] Recently, Lv et al reported an interpenetrated iron MOF PCN-245 for ethane/ethylene separation. [132] Metropolis MC calculations suggested that the interpenetrated structure of PCN-245 creates greater interaction affinity for ethane than ethylene through the crossing organic linkers, which could account for the higher uptake of ethane and ethane/ethylene separation in the adsorption column containing PCN-245.…”