Nitrogen adsorption properties of cubic and orthorhombic Li-exchanged low silica X

Thermodynamic study of LiNaKLSX zeolites with different Li exchange rate for N2/O2 separation process

“…This study focuses on zeolites and more specifically on X type faujasites which are known to present good separation performance [3]. For this type of adsorbents, it is known that interactions between extra framework cations and adsorbates play a key role in adsorption phenomena [4,5].…”

“…when K + cations are replaced by Na + cations or Na + cations are replaced by Li + cations [6][7][8]. The Si/Al ratio also has an influence and better results were obtained when Si/Al tends to 1 [3,9]. In this study, the effect of Li exchange rate on the adsorption capacities and selectivities was investigated on set a of LSX zeolites with Si/Al = 1.01; the range of zeolites used is from Li80%NaKLSX to Li100%LSX, which is considered as the best adsorbent for nitrogen-oxygen separation in the PSA process [10,11].…”

Macrocyclic Weakly Coordinating Anions

“…[40,41] Equilibrium geometry DFT calculations at the M06 6-331G* level (no superposition error correction) using the Spartan 8s oftware [42] were carried out on WCA 2 with Li ). [43] The results indicatet hat M-WCAsc an reach higher binding energies forN 2 compared to zeolites.E quilibrium geometry DFT calculationsa tthe M06 6-331G*level (no superposition error correction) for WCA 2 with Li + cations as model for M-WCA type 2g ave ar ather low bindinge nergy of only 26 kJ mol À1 for CH 4 ,w hich is smaller than that forN 2 (38 kJ mol À1 ). N 2 is the minor component in natural gas compared to CH 4 and therefore as orbentt hat adsorbs N 2 more strongly than CH 4 is preferred.…”

Li+- and H+-Exchanged Low-Silica X Zeolite as Selective Nitrogen Adsorbent for Air Separation

“…Recently, Li-LSX has been considered to be the best adsorbent for oxygen PSA. [6][7][8][9][10][11][12][13] However, the higher Liexchange ratio should be required to prepare the Li-LSX with high performance to oxygen producing by P(V)SA. 6,7,12 Compared with the other available cations for selective nitrogen adsorption like Ca, Li source is expensive and it was reported that the Li ions are hard to be exchanged to X zeolite.…”

“…15,16 Yoshida et al reported that the nitrogen adsorption capacities of Liexchanged FAU type zeolites such as LSX, X and Y is related to the location of Li ions in FAU structure. 12,13 In this study, ammonium ions were introduced as second cation. The ammonium ions were transformed into proton by desorption of ammonia with calcinations.…”