Effects of an Alternating Magnetic Field towards Dispersion of α-Fe2O3/TiO2 Magnetic Filler in PPOdm Polymer for CO2/CH4 Gas Separation

Abstract

Magnetic-field-induced dispersion of magnetic fillers has been proven to improve the gas separation performance of mixed matrix membranes (MMMs). However, the magnetic field induced is usually in a horizontal or vertical direction. Limited study has been conducted on the effects of alternating magnetic field (AMF) direction towards the dispersion of particles. Thus, this work focuses on the incorporation and dispersion of ferromagnetic iron oxide–titanium (IV) dioxide (αFe2O3/TiO2) particles in a poly (2,6-dimethyl-1,4-phenylene) oxide (PPOdm) membrane via an AMF to investigate its effect on the magnetic filler dispersion and correlation towards gas separation performance. The fillers were incorporated into PPOdm polymer via a spin-coating method at a 1, 3, and 5 wt% filler loading. The MMM with the 3 wt% loading showed the best performance in terms of particle dispersion and gas separation performance. The three MMMs were refabricated in an alternating magnetic field, and the MMM with the 3 wt% loading presented the best performance. The results display an increment in selectivity by 100% and a decrement in CO2 permeability by 97% to an unmagnetized MMM for the 3 wt% loading. The degree of filler dispersion was quantified and measured using Area Disorder of Delaunay Triangulation mapped onto the filler on binarized MMM images. The results indicate that the magnetized MMM presents a greater degree of dispersion than the unmagnetized MMM.

Characterization of aperiodic surfaces with mesh-based parameters

“…Histograms are also used to give an overview of the distribution of side lengths [9,21,23]. Some papers also calculate the areas and their statistics [23,24]. According to Bakshi et al [6] a higher mean and smaller standard deviation of the side lengths indicate better and more uniform distributions.…”

Influence of alternating magnetic field's frequency and exposure time on distribution of α‐Fe2O3/TiO2 fillers for gas separation membranes: Quantitative approach

“…Magnetized MMMs display a relatively lower agglomeration size, increased degree of dispersion, and higher particle counts, along with higher selectivity than their unmagnetized counterparts. 18 However, there are other parameters such as alternating magnetic field (AMF) strength, magnetic field frequency, and magnetic field exposure time that influenced the dispersion of the nanoparticles. 16, 19 Spencer, Gao, and Yamamoto 19 showed that super paramagnetic iron oxide nanoparticles (SPION) assemble themselves through an oscillating magnetic field.…”

“…The current work is an extension from the previous study and focuses on the mentioned parameters. 18 We fabricate α-Fe 2 O 3 /TiO 2 filler and incorporate it into a polymeric matrix to allow manipulation of its overall distribution via AMF. TiO 2 nanoparticles were used to pair with iron oxide in this study as they possess a high surface area to volume ratio, resulting in agglomeration to minimize their high surface energy.…”

“…In our previous published work, AMF was applied onto MMM at different α‐Fe 2 O 3 /TiO 2 filler weight loadings and proved its contribution toward the enhancement of filler dispersion and CO 2 /CH 4 gas separation performances. Magnetized MMMs display a relatively lower agglomeration size, increased degree of dispersion, and higher particle counts, along with higher selectivity than their unmagnetized counterparts 18 . However, there are other parameters such as alternating magnetic field (AMF) strength, magnetic field frequency, and magnetic field exposure time that influenced the dispersion of the nanoparticles 16,19 .…”

“…To the best of our knowledge, the study of the frequency and exposure time parameters of AMF in MMM has not been carried out despite numerous applications in other fields. The current work is an extension from the previous study and focuses on the mentioned parameters 18 . We fabricate α‐Fe 2 O 3 /TiO 2 filler and incorporate it into a polymeric matrix to allow manipulation of its overall distribution via AMF.…”