Mixed matrix membranes of Matrimid 5218 loaded with zeolite 4A for pervaporation separation of water–isopropanol mixtures

Abstract

Mixed matrix membranes were prepared by incorporating zeolite 4A into polyimide of Matrimid 5218 using solution-casting technique. The fabricated membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and thermo gravimetric analysis (TGA). It was found that the higher annealing temperature of 250°C is more favorable to improve adhesion between zeolite and polymer phases. Effects of different parameters such as temperature (30–60°C), water content in feed (10–40wt.%), zeolite loading (0–15wt.%) and polymer content (10 and 15wt.%) on pervaporation dehydration of isopropanol were studied. Sorption studies were carried out to evaluate degree of swelling of the membranes in feed mixtures of water and isopropanol. The experimental results showed that both pervaporation flux and selectivity increase simultaneously with increasing the zeolite content in the membranes. The membrane containing Matrimid 5218 (10wt.%)–zeolite 4A (15wt.%) exhibits the highest separation factor (α) of 29,991 with a substantial permeation flux (J) of 0.021kg/m2h at 30°C for 10wt.% of water in the feed. The PV performance was also studied in term of pervaporation separation index (PSI). Permeation flux was found to follow the Arrhenius trend over the investigated temperature range.