Comparison of silica and novel functionalized silica-based cellulose acetate hybrid membranes in gas permeation study

Abstract

Cellulose acetate (CA) is a widely applied glassy polymer in the preparation of gas separation membranes. In the present study, hybrid membranes were prepared by incorporating silica (Si) and silica functionalized with ptetranitrocalix[4]arene (Si-CL) into the CA matrix, and their gas permeation abilities were explored with regard to CO 2 , N 2 and CH 4 gases. The diffusion-induced phase separation (DIPS) method was adopted to make pure CA, CA/Si, and CA/Si-CL hybrid membranes. The concentration of Si-CL was varied as 10 wt%, 20 wt% and 30 wt% in the hybrid membranes. The analytical techniques employed for membrane characterization were Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X ray-diffraction (XRD) analysis. The proper interaction of Si and Si-CL was confirmed by FTIR analysis. However, the homogenous surface textures of CA/Si, and CA/Si-CL hybrid membranes were evaluated through SEM. Furthermore, AFM analysis was performed to examine the surface roughness of these hybrid membranes. The changes in the crystallinity of CA were also examined by XRD analysis after adding Si and Si-CL. Moreover, the tensile strength of the CA/Si hybrid membrane was found to be better than that of CA/Si-CL hybrid membranes. CO 2 , CH 4 and N 2 gases were used for gas permeation experiments at 400 kPa. Among CO 2 and CH 4 gases, the permeability of N 2 was high in CA/Si-CL hybrid membranes, and N 2 /CO 2 selectivity of these membranes was 22.6.

Synthesis and Characterization of Novel Integral Asymmetric Monophasic Cellulose–Acetate/Silica/Titania and Cellulose–Acetate/Titania Membranes

“…The most intense peaks (equal intensity for all membranes in series 1) are the CA peaks found at 1045 and 1232 cm −1 , which are assigned to acetate groups (symmetric (ν s COC) and antisymmetric (ν as COC) modes, respectively [ 39 , 40 ]). The band centered at 1369 cm −1 is assigned to δ s CH 3 , and the band centered at 1741 cm −1 is assigned to the strong carbonyl stretching mode (νC=O) [ 41 , 42 ]. The broad band located at 3000–3700 cm −1 (assigned to the O–H stretching mode, νOH) [ 39 ] contains contributions from water (H–O–H), hydrolyzed silica/titania precursors (≡Si–OH − , ≡Ti–OH − ), and non-esterified cellulose polymer –OH groups.…”

“…Two important bands of CA/SiO 2 hybrid membranes are the ν(Si–O–Si) and ν(Si–O–C), observed at 1065 and 1118 cm −1 , respectively [ 24 ]. Lower intensity peaks are observed at 1433 and 1637 cm −1 (assigned to δCH 2 and δHOH, respectively) [ 41 , 42 ]. The weak band centered at 903 cm −1 confirms the presence of acetate methyl groups [ 39 ].…”

Cellulose acetate nanocomposite ultrafiltration membranes tailored with hydrous manganese dioxide nanoparticles for water treatment applications

“…It obviously shows that the diffused peaks probably due to the amorphous nature of CA and decreases the crystallinity through the hydrogen bonding between acetyl and hydroxyl groups. The diffraction pattern of HMO nanoparticles is not observed is indicated that the amorphous nature of CA is dominated …”

Carbon dioxide separation using α‐alumina ceramic tube supported cellulose triacetate‐tributyl phosphate composite membrane

“…The strong peak around 1754 cm −1 was assigned to the stretching mode of the C = O bond and another peak at 1371 cm −1 showed the bending of the C‐CH 3 group. The characteristic peaks around 1237 and 1052 cm −1 were attributed to the asymmetric stretching of ether C‐O and C‐O‐C vibrations . The incorporation of TBP in the CTA polymer matrix (Fig.…”

“…The characteristic peaks around 1237 and 1052 cm −1 were attributed to the asymmetric stretching of ether C-O and C-O-C vibrations. 23 The incorporation of TBP in the CTA polymer matrix ( Fig. 2c and d) resulted in the improved intensity of the pure CTA spectra.…”