Pervaporation dehydration of isopropyl alcohol with NaY zeolite incorporated hybrid membranes

Abstract

With a solution technique, NaY zeolite incorporated, tetraethylorthosilicate-crosslinked poly(vinyl alcohol) membranes were prepared. The resulting membranes were tested for their ability to separate isopropyl alcohol/water mixtures by pervaporation in the temperature range of 30-508C. The effects of the zeolite content and feed composition on the pervaporation performance of the membranes were investigated. The experimental results demonstrated that both flux and selectivity increased simultaneously with increasing zeolite content in the membranes. This was explained on the basis of the enhancement of hydrophilicity, selective adsorption, and establishment of a molecular sieving action attributed to the creation of pores in the membrane matrix. The membrane containing 15 mass % zeolite exhibited the highest separation selectivity of 3991 with a flux of 5.39 3 10 22 kg/m 2 h with 10 mass % water in the feed at 308C. The total flux and flux of water were close to each other for almost all the studied membranes, and this suggested that the membranes could be used effectively to break the azeotropic point of water/isopropyl alcohol mixtures to remove a small amount of water from isopropyl alcohol. From the temperature-dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The activation energy values obtained for water were significantly lower than those for isopropyl alcohol, and this suggested that the developed membranes had a higher separation efficiency for water/isopropyl alcohol systems. The activation energy values for total permeation and water permeation were found to be almost the same for all the membranes, and this signified that coupled transport was minimal because of the highly selective nature of the membranes. Positive heat of sorption values were observed in all the membranes, and this suggested that Henry's mode of sorption was predominant.

Pervaporation separation of water–isopropyl alcohol mixture by PVA/LiBr membrane

“…Pervaporation (PV) separation is an energy-intensive membrane-based process that has been well-recognized in the separation of azeotropic organic-aqueous mixtures that have close boiling points [1][2][3][4][5]. PV has been a widely-used technique in the dehydration of alcohols, especially isopropyl alcohol [6][7][8][9][10][11][12][13][14][15][16][17][18], ethylene glycol [19,20], and ethanol [6,[21][22][23]. In this ecofriendly process, the driving force for molecular transport from the feed mixture on the upstream side to the vapor permeate downstream is the chemical potential gradient, which is created by maintaining the applied pressure lower than the saturation pressure on the downstream [24].…”

Influence of reactant concentration on formation of AgCl particles in PEO–PPO–PEO microemulsion and morphology and performance of AgCl–PMMA membranes

“…With wide application of membrane separation in environment removal and chemical industry, researches on synthesis of membrane have paid more attention in enhancing the separation performance of membranes significantly. Because of excellent separation performance for some organic compounds, inorganic filled organic–inorganic hybrid membranes have attracted much interest 1–4. For instance, membranes filled with AgCl nanoparticles could separate several olefin/alkanes efficiently, due to π‐complexation between Ag ion in membranes and unsaturated hydrocarbons 5, 6…”