Exfoliated Titanosilicate Material UZAR‐S1 Obtained from JDF‐L1

Abstract

A new material, UZAR‐S1, has been obtained by exfoliation of the layered precursor microporous titanosilicate JDF‐L1. The exfoliation consists of a first stage of proton exchange with histidine followed by intercalation with nonylamine and final extraction in HCl/water/ethanol solution. UZAR‐S1 is an exfoliated material composed of sheets of a few nanometers of thickness with a high aspect ratio, a BET specific surface area of 160 m2/g (JDF‐L1 scarcely adsorbs N2), and a Si/Ti atomic ratio below 6. The dispersion of this material in commercial polysulfone results in an improved H2‐selective mixed matrix membrane.

Synthesis, Swelling, and Exfoliation of Microporous Lamellar Titanosilicate AM‐4

“…This peak allows the estimation of a layer spacing of 31.0 Ϯ 0.3 Å. This is comparable to that observed in the swelling of the layered titanosilicate JDF-L1 with a basal spacing of 29.6 Ϯ 1.4 Å, and is consistent with a bilayer surfactant configuration, [19] as the nonylamine molecular length is about 14 Å. The spacing between the layers is corroborated by TEM.…”

“…The Na/Ti ratio decreased upon swelling with nonylamine and further extraction in acid, corroborating the hypothesis of Na + exchange by protons. The Si/Ti ratio does not seem to decrease as much as it did for JDF-L1, [19] where the theoretical Si/Ti ratio of the layered precursor material is double that of AM-4. …”

Separation of H₂ and CO₂ Containing Mixtures with Mixed Matrix Membranes Based on Layered Materials

“…Numerous molecular sieving platelets of different nature have been identified as potential filler materials in membrane applications [24,47], and in particular in the preparation of MMMs: layered zeolites (MCM-22P [49], PREFER [50] and Nu-6(1) [51], and their corresponding delaminated zeolites ITQ-2 [43], ITQ-6 [52] and ITQ-18 [53], respectively, or MFI nanosheets [54]); layered silicates (Na and Sr silicate AHM-3 [55]) including the impermeable nanoclays [47,56]; pseudozeolites (layered aluminophosfate, AlPO) [24]; and titanosilicates (JDF-L1) [57]. In Table 1 MMMs prepared with different flakes (layered silicates, zeolites and pseudozeolites) are classified and a detailed discussion will be presented below.…”

“…They Like previously discussed layered zeolites and AlPOs, JDF-L1 can be swollen via intercalation reaction (with nonylamine) and a separation between the layers of 3 nm is achieved. After subsequent delamination via chemical extraction UZAR-S1 is obtained [57]. Even though JDF-L1 scarcely adsorbs N 2 (BET specific surface area is 30 m 2 /g), UZAR-S1 presents a specific surface area of up to 204 m 2 /g due to its fine particle size with high aspect ratio and thickness as low as 5 nm.…”

“…Even though JDF-L1 scarcely adsorbs N 2 (BET specific surface area is 30 m 2 /g), UZAR-S1 presents a specific surface area of up to 204 m 2 /g due to its fine particle size with high aspect ratio and thickness as low as 5 nm. UZAR-S1 was tested as a MMM filler with PSF [57], so that the nanometer-like particles produced upon the exfoliation step were observed by TEM into the membrane. Additionally, the presence of some aggregates indicated that, even though the swelling and exfoliation steps affect most of the precursor material, some particles with relatively large sizes would remain.…”