Functionalized Graphene Sheets Embedded in Chitosan Nanocomposite Membranes for Ethanol and Isopropanol Dehydration via Pervaporation

Abstract

Pervaporation is an important alternative membrane separation process compared to the distillation technique, and a relatively high separation factor is required to lower the energy demand. Solution processable nanocomposite membranes prepared by incorporating functionalized graphene sheets (FGS) loaded in various concentrations into the chitosan matrix have been employed for the pervaporative dehydration of ethanol and isopropanol. Incorporation of FGS leads to an increase of surface hydrophilicity of the chitosan membranes along with an increase in membrane tortuosity that was favorable to the selective permeation of water molecules. The nanocomposite membrane containing 2.5 wt % FGS gave the highest selectivities of 7781 and 1093 for isopropanol−water and ethanol−water mixtures, respectively, when tested for 10 wt % water-containing feed mixture. Membranes were characterized by wide-angle XRD, SEM, contact angle, and optical profilometry techniques. The Flory−Huggins theory was employed to estimate the polymer−solvent interaction parameter. Diffusion values and Arrhenius activation energy parameters provided quantitative evidence for the observed increase in water selectivity at higher loading of FGS.

Effect of polystyrene stars with fullerene C60cores on pervaporation properties of poly(phenylene oxide) membrane

“…Data for temperature dependence of total flux and separation factor can be used to estimate effective activation energies of permeation through membranes . The permeation of small molecules through a membrane is a temperature‐dependent and thermally activated phenomenon .…”

Synthesis of carbon quantum dots to fabricate ultraviolet‐shielding poly(vinylidene fluoride) films

“…Water contact angles were measured to investigate the surface wettability of the PVDF film before and after modification . As shown in Figure , the contact angle of the pure PVDF film was 100°.…”

“…Water contact angles were measured to investigate the surface wettability of the PVDF film before and after modification. [46][47][48] As shown in Figure 9, the contact angle of the pure PVDF film was 100 . After the film was treated with the alkaline solution, the angle decreased to 66 , indicating the hydrophilic property.…”

Ethanol purification from methanol via pervaporation using polybеnzoхazinonеimidе membrane

“…7 shows the logarithmic dependence of the individual fluxes on the inverse temperature in pervaporation of the three compositions of methanol/ethanol mixtures (5:95), (10:90), and (20:80) wt.%. The linear type of curves gives an opportunity to estimate the activation energies of individual components permeation using the Arrhenius type equation [38][39][40][41]:…”