Effect of dodeca‐tungstophosphric acid on morphology and performance of polyvinyl alcohol membrane for gas separation

Abstract

In this article, organic/inorganic membrane was prepared for gas separation by incorporating dodecatungstophosphric acid (PWA) into the base polymer. Flatsheet composite membranes were produced via dry-phase inversion method. In the first stage, the effects of PWA concentration on morphology and performance of polyvinyl alcohol (PVA) membranes were elucidated. For this stage, the preparation of membranes was carried out at constant temperature of 40 C. The porosity of the prepared membrane was slightly increased with addition of PWA. By increasing the PWA concentration up to 6 wt % in the membrane recipe, the permeability of N 2 , O 2 , and air was improved from 50,000 (for no addition of PWA) to around 160,000, 140,000, and 80,000 L m À2 h À1, respectively. For H 2 , this was enhanced from 110,000 to 230,000 L m À2 h À1 . The ideal selectivity of the membrane was slightly improved for N 2 /air (from 1 to 1.2). For N 2 /O 2 pair, the initial drop (from 2.5 to 1.5) was followed by a slight increase (1.5-1.9). Moreover, the selectivity was decreased for H 2 /air (from 2.8 to 1.8) and H 2 /N 2 (from 2.2 to 1.7) by increasing the PWA concentration. The 10 wt % PVA membrane with 6 wt % PWA demonstrated superior performance compared with the other compositions. In summary, the presence of PWA in the casting solution results in lower flux for O 2 and higher selectivity for H 2 /O 2 pair. In the second stage, the effects of solvent evaporation temperature (10, 27, 40, and 80 C) on morphology and performance of the membranes were studied. By increasing the temperature, the number and size of voids were increased.

Protein-Resistant Cross-Linked Poly(vinyl alcohol) Micropatterns via Photolithography Using Removable Polyoxometalate Photocatalyst

“…These findings are in accordance with previous reports claiming the creation of hydrogen bonds between the hydroxyl groups of PVA and POMs in hydrophilic hybrid membranes. 41,42 Thus, as it is shown in Figure 3A, the most efficient developers for the 12-tungstophosphoric acid removal were the 1:1 (v/v) methanol/deionized water solution and the 0.26 N TMAH solution. Deionized water was not able to fully remove from the cross-linked film.…”

The influence of membrane formation parameters on structural morphology and performance of PES/PDMS composite membrane for gas separation

“…Developing and improving membranes for increasing separation efficiency of O 2 from N 2 is one of the interesting fields for researchers. For this purpose, preparation and application capability of hollow fiber,3, 4 flat sheet,5, 6 and carbon molecular sieving (CMS)7, 8 membranes were examined.…”