Fabrication of a layered hybrid membrane using an organosilica separation layer on a porous polysulfone support, and the application to vapor permeation

Abstract

Using 1,2-bis(triethoxysilyl)ethane (BTESE) as a single precursor, a uniform, defect-free and perm-selective organosilica layer was successfully deposited onto porous polysulfone ultrafiltration (PSF-UF) supports via a simple sol-gel spin-coating and thermal-treatment process. The layered hybrid membranes, where BTESE-derived SiO2 is deposited on polymer supports, were applied to the vapor permeation dehydration of isopropanol-water (90/10 wt%) solutions at 105 ºC, and demonstrated a water flux of 1.6 kg/(m 2 h) and a separation factor of 315 with no selectivity for a PSF-UF support. Long-term stability testing of vapor permeation also confirmed the excellent stability of these BTESE/PSF-UF layered hybrid membranes. Moreover, compared with porous PSF-UF supports, this layered hybrid membrane also showed improved gas separation performance and a moderate (≈10) separation factor for H2/N2.

Reverse osmosis performance of layered-hybrid membranes consisting of an organosilica separation layer on polymer supports

“…However, a sharp decrease in water permeability was seen when the heat-treatment temperature was higher than 150°C. This result agreed with previous reports [23,29]. This happened because the highest heattreatment temperature approximated the glass transition temperature (T g ¼ 185°C) of polysulfone (PSF), which changed the RO performance of the NTR membranes.…”

“…). It is worth noting that the number of spin coating cycles played a crucial role in avoiding the formation of defects in the BTESE layer on the NTR support surface in our previous reports [23,29]. After 2 spin-coating cycles, a thin, uniform and complete BTESE-derived silica separation layer was deposited onto the NTR support (BTESE/NTR layered-hybrid) membrane.…”

“…BTESE polymeric sols were synthesized via the hydrolysis and polymerization reaction of a BTESE precursor with water and HCl in 1-propanol by following a procedure established in our previous report [23]. Briefly, a required amount of BTESE was mixed with 1-propanol.…”

“…The polymer-supported BTESE layered-hybrid membranes were fabricated via a sol-gel spin-coating process, as described elsewhere [23]. Briefly, the NTR support (diameter: 2.5 cm) was placed onto a spin coater.…”

“…More recently, a new type of layered-hybrid membrane composed of a high-performance inorganic separation layer on a polymeric support has been successfully developed and applied to several membrane separation processes [20][21][22][23]. For example, Nair et al attempted to fabricate zeolitic imidazolate framework (ZIF) membranes on polymeric hollow fibers.…”