Development of Halloysite Nanotubes (HNT) Incorporated Crosslinked Sodium Alginate Membranes for Dehydration of Isopropanol Using Pervaporation Separation

ABSTRACT Pervaporation (PV) separation of azeotropic mixtures has shown considerable potential as an alternative to distillation. However, developing high‐performance PV membranes with a high flux and separation factor has been a significant challenge in this process. In this work, we have developed halloysite nanotube (HNT) incorporated sodium alginate (NaAlg) membranes crosslinked with poly(styrene sulfonic acid‐co‐maleic acid) (PSSA‐co‐MA). The developed membranes contained 0, 5, 10, 15, and 20 mass% of HNT with respect to NaAlg. An equilibrium swelling experiment was carried out using various compositions of water and isopropanol mixtures. The separation performance of HNT incorporated NaAlg‐PSSAMA membranes was examined systematically for the separation of isopropanol azeotropic mixtures at various temperatures. The membranes containing 20 mass% of HNT exhibited the maximum separation factor ( α ) of 14,785, with a flux ( J ) of 21.08 × 10 −2 kg m −2 h −1 at 30°C for 10 mass% of water in the feed. These membranes were capable of breaking the azeotropic point of mixtures of water–isopropanol efficiently. The activation energy values obtained for water permeation were much lower than those obtained for isopropanol permeation, indicating that these membranes had good separation capacity for the water–isopropanol system. The activation energy for total permeation ( E P ) for the membranes M‐0 and M‐4 are 20.95 and 23.37 kJ mol −1 , respectively. Similarly, the activation energy for total permeation diffusion ( E D ) for the membranes M‐0 and M‐4 are 21.76 and 25.48 kJ mol −1 , respectively. The enthalpy values of all the membranes are negative, indicating that Langmuir's mechanism of sorption predominated the process.