Molecular simulation and experimental investigation of temperature effect on chitosan-nanosilica supported mixed matrix membranes for dehydration of ethanol via pervaporation

- 3 different MMMs were synthesized and simulated by MD approach for pervaporation of ethanol.
- SiO2 fillers were used in the chitosan membrane in three operating temperatures.
- Transport and separation properties increased by fillers.
- Simulation results showed good agreements with experimental results.

In this study, novel chitosan/silica mixed matrix membranes were prepared by 10 wt% loading of TEOS and APTEOS into chitosan matrix and simultaneously results were simulated by molecular simulation methods to investigate the reliability of the experiment results. The fabricated membranes were structurally characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and operationally evaluated by ethanol dehydration permeation tests. SEM analysis showed a uniform distribution of silica nanoparticles in the polymer matrix. FTIR analysis indicated that, compared to the neat membrane, the presence of APTEOS and TEOS initiators caused formation of stronger bonds of hydroxyl (OH) and amino (NH) groups. The XRD test was also done by molecular simulation to investigate the crystallinity of the simulated membranes. Results revealed that membrane containing APTEOS was more amorphous than membrane containing TEOS. Also, the glass transition temperatures the membranes containing APTEOS and TEOS was calculated to be 162 and 160.8 °C, respectively. Permeation test results indicated that for both membranes the permeation flux increased and separation factor decreased with temperature. The maximum flux and best separation factor for CS/APTEOS and CS/TEOS were obtained at 70 °C and 30 °C, respectively. Chitosan/TEOS membrane showed the best separation factor of 450 in 30 °C, while for Chitosan/APTEOS membrane this value was less than 400. CS/APTEOS membrane showed better pervaporation separation index (PSI); however, the results showed that separation index of both membranes, which was initially more than 320 in 30 °C, decreased with temperature and reached to less than 130 in 70 °C. Also, the simulation results were in good agreement with experiment results.