Regeneration of granular activated carbon saturated with gaseous toluene by microwave irradiation

This paper describes laboratory-scale experiments examining the impact of microwave irradiation on the regeneration of granular activated carbon (GAC) exposed to toluene vapor. A stream containing 300 ppm of toluene was passed through the GAC. The saturated adsorbent was treated by microwave irradiation at a heating frequency of 2450 MHz at various power levels to evaporate the adsorbate. The adsorption capacity was evaluated through breakthrough curves and the residue was analyzed by gas chromatography. We found that exposing GAC saturated with toluene under microwave irradiation at 900 W for 15 min could remove the pollutant from the adsorbent effectively. The regeneration efficiency was more than 95% after 5 cycles at higher power levels. The GAC surface area was increased from 1150 m2 /g to 1185 m2 /g over regeneration cycles. We concluded that GAC could be reused after repeated regeneration cycles under microwave irradiation while maintaining its original adsorption capacity and physical properties. © TÜBITAK.