A dataset for Surface silanization of Li-LSX: balancing N2/O2 separation performance and hydrothermal stability

After cooling to room temperature, the organosilane-functionalized zeolites were collected via filtration, washing with ethanol and distilled water, and drying in an oven at 80 oC overnight. The as-prepared samples were denoted as Li-LSX-OTMS-x, where x represents the organosilane-to-zeolite mass ratio. X-ray diffraction (XRD) patterns were collected on a Bruker D8 Advance diffractometer equipped with Cu Kα radiation (λ = 0.1541 nm).

The scanning rate was set to 5 °/min over a 2θ range of 5–60°. Fourier-transform infrared (FT-IR) spectra were acquired on a Nicolet 380 spectrometer via the KBr pellet method. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) spectroscopy using a Hitachi FlexSEM1000 microscope was utilized to characterize the surface morphology and elemental composition of the as-prepared samples.

Inductively coupled plasma atomic emission spectroscopy (ICP-AES, Varian 715-ES) was adopted to quantify elemental concentrations of the samples, from which the Si/Al molar ratio and Li/Al molar ratio were calculated. Static contact angle measurement (CAM) was carried out using an SDC-100 contact angle goniometer (Sindin, China) to evaluate the surface hydrophilic-hydrophobic properties of samples. Deionized water was adopted as the probe liquid, with a consistent droplet volume of 5 μL for each test.

Droplets were deposited onto the sample surface via a micro-syringe, and contact angle values were calculated using the angle-measuring method after image capture. The measurable range of the instrument was 0–180°. N₂ adsorption–desorption measurements at 77 K were performed on a Quantachrome Autosorb-1 instrument to analyze the textural properties of the adsorbents.

The Brunauer–Emmett–Teller (BET) model was applied to calculate the specific surface area (SBET) and total pore volume (Vtotal). The t-plot method was used to determine the micropore surface area (Smicro) and micropore volume (Vmicro). Thermal properties of the samples were characterized by thermogravimetric (TG) analysis.

The measurements were carried out on a Perkin-Elmer Pyris1 instrument under an air atmosphere, with a heating ramp of 10 °/min from room temperature to 400 °C to record the weight loss of samples.Figure 1. Nitrogen adsorption-desorption isotherms and intercrystalline mesopore size distributions (inset) of pristine and OTMS-modified Li-LSX zeolites. Figure 2. XRD patterns of pristine and OTMS-modified Li-LSX zeolites. Figure 3.

FT-IR spectra of pristine and OTMS-modified Li-LSX zeolites. Figure 4. SEM images (a-d) and water contact angle measurements (e-h) of pristine and OTMS-modified Li-LSX zeolites. Figure 5. TG analysis for pristine and OTMS-modified Li-LSX zeolites. Figure 6.

Single-component adsorption isotherms of N2 (a) and O2 (b) at 298 K for pristine and OTMS-modified Li-LSX zeolites, with saturated adsorption capacities at P/P0 = 1 listed in the inset table. Figure 7. Evolution of N2/O2 adsorption capacities, IAST selectivity and crystallinity during cyclic hydrothermal-aging tests of Li-LSX and OTMS-modified sample. Scheme 1. Proposed reaction pathways for OTMS grafting on the surface of Li-LSX zeolite. Table 1.

Chemical composition and textural properties of pristine and OTMS-modified Li-LSX zeolites. Table 2. Binary N2/O2 adsorption capacities and IAST selectivity of pristine and OTMS-modified Li-LSX zeolites.