Comparison of the pervaporation separation of a water–acetonitrile mixture with zeolite‐filled sodium alginate and poly(vinyl alcohol)–polyaniline semi‐interpenetrating polymer network membranes

Abstract

ABSTRACT:The pervaporation (PV) separation performance of ZSM-5-and Na-Y-type zeolite-filled sodium alginate (NaAlg) membranes were compared with those of pure NaAlg and semi-interpenetrating polymer network (semi-IPN) membranes of poly(vinyl alcohol) (PVA) with polyaniline (PANI) for the dehydration of acetonitrile. The PV separation characteristics of the zeolite-filled membranes showed a dependence on the nature of the zeolites. The variation of the acidity function of the ZSM-5 zeolite had an influence on the flux and selectivity of the membranes when compared to unfilled membranes. The crosslinked membranes were characterized by differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Increasing the PANI content of the semi-IPN network increased the separation selectivity. Among the NaAlg membranes, the plain NaAlg membrane showed the highest selectivity of 414 at 30 mass % water in the feed mixture, whereas the Na-Y-and ZSM-5 (40)-filled NaAlg membranes exhibited much lower values of selectivity, that is, 7.3 and 4.3, respectively for 30 mass % water in the feed. When the flux and selectivity data of ZSM-5 (250)-filled NaAlg membranes were compared with that of Na-Y-or ZSM-5 (40)-filled NaAlg membranes, a noticeable increase in the selectivity for the ZSM-5 (250)-filled NaAlg membrane was observed, but a somewhat comparable flux was observed compared to the plain NaAlg membrane. For the first time, PANI was polymerized with PVA to yield a semi-IPN. The total flux and water flux increased systematically, whereas the selectivity decreased greatly from 251.87 to 5.95 with increasing amounts of water in the feed.

Preparation and characterization of filled matrix membranes of sodium alginate incorporated with aluminum-containing mesoporous silica for pervaporation dehydration of alcohols

“…(3) by considering weights of the wet membrane and sorbed membrane at equilibrium as a function of time [9][10][11]. Pervaporation results are greatly influenced by membrane swelling.…”

“…By far, majority of studies on zeolite-filled membranes have dealt with zeolite A [7,8], FAU-type zeolites (X and Y) [12][13][14], mordenite [15,16], MFI-type zeolite (ZSM-5 and silicalite) [17][18][19], zeolite NaA membranes [20,21], etc. In our previous studies on zeolite/particulate filled PV membranes, we have observed that incorporation of small molecular size zeolite fillers could enhance tremendously the PV performances [9][10][11]. By increasing aluminum (Al) content of the zeolite framework, its hydrophilicity increases, but acid resistivity will decrease because strong acid leaches aluminum from the zeolite to decompose its framework structure [22].…”

“…Generally, distillation employed to purify alcohols requires adding an entrainer liquid such as benzene that makes the process more hazardous, but PV should overcome these drawbacks, since the membrane acts as a third phase to break the azeotrope. Among the various membranes used in PV, zeolite-filled membranes are now being widely used in view of their better advantages over the plain conventional polymeric membranes [9][10][11]. Such filled membranes are chemically and thermally more stable and exhibit better potential than pristine membrane in separating liquids by adsorptive and molecular sieving effects, because the zeolite pores have molecular sizes that can affect the separation more effectively [12].…”

Poly(vinyl alcohol)–zeolite T mixed matrix composite membranes for pervaporation separation of water+1,4-dioxane mixtures

“…It has been earlier reported [9,11,15] that the addition of fillers would improve the PV performance of organic polymeric membranes. In continuation of our ongoing program of research to develop filled matrix composite membranes, we report here the development of mixed matrix composite membranes by incorporating zeolite-T particles in different amounts (5, 10 and 15 wt.%) with respect to weight of PVA.…”

“…PVA is a water-soluble polyhydroxy polymer, which has been widely employed in engineering applications due to its ease of preparation, excellent film forming property, good chemical resistance, physico-chemical properties and its biodegradable nature [15,16]. Even though PVA has good mechanical strength properties in a dry state, its hydrophilicity limits the applications as a PV membrane [17,18].…”