Separation of sulfur hexafluoride (SF6) from ternary gas mixtures using commercial polysulfone (PSf) hollow fiber membranes

The separation of sulfur hexafluoride (SF6), a powerful anthropogenic greenhouse gas, was investigated using membrane technology. Permeation measurements in commercial polysulfone (PSf) hollow fiber membranes were performed using single gases (i.e. N2, O2 and SF6) to investigate the effect of temperature and pressure on separation performance. The permeation experiments of ternary gas mixtures (N2/O2/SF6) were also conducted under various operational conditions, including pressure, temperature, stage cut (permeation flow rate/feed flow rate) and gas compositions. The results showed that the SF6 treatment capacity increased with increase in temperature or pressure, but decreased with increasing stage cut and SF6 content in the feed gas mixture. At higher temperatures, the membrane exhibited higher performance for the separation, recovery and enrichment of SF6. A feed with a higher pressure or a lower stage cut resulted in lower SF6 separation and enrichment efficiency, but a higher recovery. The separation of SF6 from a gas mixture with higher contents of SF6 exhibited lower SF6 recovery and enrichment performance. Our current work demonstrated more realistic performance of the commercial PSf hollow fiber membrane for the separation, enrichment and recovery of SF6.