Investigation the performance of Polysulfone/Neodymium Magnetic Mixed-Matrix Membranes for O2/N2 Separation

Research subject:

 In recent years, many efforts have been made to improve the performance of polymer membranes in oxygen-nitrogen separation due to the high cost and energy consumption of cryogenic distillation and adsorption methods. Increasing the performance of these types of membranes is still needed for industrial applications.

Research approach: 

In this research, novel magnetic mixed matrix membranes (MMMs) were prepared using polysulfone (PSf) as the main matrix, and also neodymium (Nd) as the magnetic particles for O2/N2 separation. To avoid the particle sedimentation and proper dispersion of particles across the membrane thickness, magnetic particle dispersion in the PSf was controlled by applying an external magnetic field (MF). The effect of Nd magnetic particle content on the microstructure, magnetic properties and thermal stability of the prepared MMMs were investigated using scanning electron microscopy, vibrating sample magnetometer and thermo-gravimetric analysis. In this reseach, a novel magnetic module was designed and constructed to investigate the performance of prepared membranes in the presence of various MFs.

The obtained results indicated that the permeability of O2 and N2 gases was improved by adding Nd magnetic particles into PSf matrix regardless of the amount of MF due to the chain packing of polymers disruption and free volume enhancement. The permeability of O2 and N2 in the MMMs containing 5 wt.% Nd in the absence of MF was about 182 % and 443%, respectively, higher than those of neat PSf membranes. Furthermore, the permeability and selectivity of PSf and PSf-Nd membranes were considerably improved by applying the MF during the permeation experiments. In the MMMs containing 5 wt.% Nd, O2/N2 selectivity was increased from 2.73 to 3.77 upon an increase in the intensity of MF from 0 to 570 mT. Considering the findings, the application of Nd particles and MF during the membrane preparation and separation processes can be facile methods for enhancement of membrane performance.