Using Microwave Radiation to Recover Granular Activated Carbon Exposed to Toluene Vapor

This paper describes laboratory scale experiments examining the impact of microwave irradiation on the Granular Activated Carbon (GAC) exposed to toluene, a common organic vapor frequently released into work environment as well as outdoor. A stream containing 300 ppm toluene was supplied and passed through the granular activated carbon. The saturated adsorbent was placed in a quartz glass reactor and treated by microwave irradiation at heating frequency of 2450 MHz at different power levels. After successive recovery cycles the adsorption capacity was evaluated through breakthrough curves and the residue analyzed by gas chromatography. We found that exposing GAC saturated with toluene under microwave irradiation at 900W for 15 minutes can remove the pollutant from the adsorbent effectively. The recovery efficiency was more than 95% after 10 cycles at high power levels. GAC surface area and porosity values were increased slightly over recovery cycles. Our experiments indicate that GAC could be reused after several cycles of treatment and recovery processes while maintaining its original adsorption capacity and physical properties.