Separation of perfluorinated electron specialty gases on microporous carbon adsorbents with record selectivity

Abstract

Separation and recovery of SF6 and CF4 from N2 is an urgent task to migrate greenhouse effect and obtain high value-added products in semiconductor industry. Adsorption separation technology based on carbon adsorbents is appealing for SF6/N2 and CF4/N2 separation, while to fabricate microporous carbon adsorbents via facile environmentally friendly method is still in great demand. In this work, a series of poly(vinylidene chloride) resins derived microporous carbon adsorbents by activating reagent-free pyrolysis were reported for selective recognition and capture of SF6 and CF4. Benefit from the ultrahigh BET specific surface areas and large pore volumes, high uptake of SF6 and CF4 were achieved on these carbon adsorbents. Moreover, C-PVDC-800 exhibited a record-high IAST selectivity of SF6/N2 (244.8) at 100 kPa and 298 K among all reported carbon adsorbents. Similarly, the IAST selectivity of CF4/N2 on C-PVDC-700 at 298 K and 100 kPa reached up to 13.2, also outperforming adsorbents reported so far. Kinetic adsorption tests and breakthrough experiments further confirmed the excellent separation performance of SF6/N2 and CF4/N2. Facile preparation process, high adsorption uptake, record-high selectivity, fast adsorption kinetics combined with robust stability make these carbon adsorbents highly promising in practical separation process.