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Showing 2 results for Raveshiyan


Volume 4, Issue 2 (Summer 2020)
Abstract

Abstract
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.
Main Results: 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.
 
Keywords: Oxygen/nitrogen separation; Polysulfone; Neodymium; Magnetic mixed-matrix membranes; Magnetic separation module
 

Volume 6, Issue 2 (Summer 2022)
Abstract

In recent years, air separation using membranes has received much attention as a cost-effective technology for producing relatively pure streams of nitrogen and oxygen. The results of studies show that the design and fabrication of new polymers with the desired structure for the industrialization of polymer membrane technology in the field of oxygen separation from nitrogen is considered very important. The results obtained from various research works show that polymer membranes made on the basis of aromatic polyimides and PIMs due to high selectivity, suitable mechanical, thermal and chemical properties and also benefiting from different structures due to polymer substitutions are a suitable option for separation of oxygen and nitrogen. Moreover, the membrane modification process can greatly increase the mechanical, chemical and selectivity of the membranes and be an effective way to improve the separation of oxygen from nitrogen. The results indicate that the fabrication of blended membranes has increased the selectivity and permeability of the membranes, and the creation of transverse connections in most cases has increased the selectivity of the membranes. Meanwhile, carbon molecular sieve membranes that are made by thermal decomposition of the polymeric raw material under controlled temperature and pressure conditions due to their properties such as high selectivity and permeability, stability in corrosive environments and applicability at high temperatures are suitable options for separation of oxygen and nitrogen. Also, carefully in the results obtained from various research works, it can be seen that the use of driving force and magnetic particles in the polymer simultaneously improves the permeability and selectivity of membranes. As it is predicted, this method is one of the efficient methods in improving the performance of polymer membranes in the field of oxygen and nitrogen separation.

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