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.