The efficacy of GAC/MgO composite for destructive adsorption of benzene from waste air stream

The new adsorbent was developed from impregnation of granular activated carbon (GAC) with MgO named GAC/MgO composite. The prepared GAC/MgO composite was a microporous material with the BET specific surface area of 1036 m2/g. Several functional groups including hydroxyl, methyl and methylene, aromatic CC, and carboxylic groups were identified on the surface of the GAC/MgO composite. The benzene adsorption potential of the GAC/MgO composite as compared with the GAC was investigated at inlet concentration of 80, 200, and 400 ppm using a bench scale adsorption column. The breakthrough time of the GAC/MgO bed for inlet concentration of 80, 200, and 400 ppm was >450, 44, and 28 h, with the specific adsorption capacity of >5164, 1263, and 1493 mg benzene/g GAC/MgO, respectively. In comparison, the breakthrough time of the GAC bed for inlet concentration of 80, 200, and 400 ppm was 36, 7, and 3 h, with the specific adsorption capacity of 413, 187, and 172 mg benzene/g GAC, respectively. The experimental results of benzene adsorption onto both GAC and GAC/MgO composite well fitted with the Yoon-Nelson model. The mass balance analysis revealed that the GAC/MgO composite had the potential of destructive sorbent, so that around 98% of the adsorbed benzene was destructed. Overall, the finding of this work suggests that the prepared GAC/MgO composite is an efficient and promising material for removal of aromatic hydrocarbons from the waste air stream.