The efficacy of the ozonation process in the presence of activated carbon impregnated with magnesium oxide in the removal of benzene from the air stream

Abstract

The main purpose of this study was to investigate the catalytic ozonation process with GAC–MgO in removal of benzene in air streams. The flow diagram of the experimental bench-scale setup included a glass column (internal diameter = 3 cm) packed for 10 cm with granular activated carbon coated with magnesium oxide. Different initial concentrations of benzene (80, 200 and 400 ppm) were used to evaluate the removal efficiency. The synthesized granular activated carbon coated by magnesium oxide was a microporous adsorbent with the BET specific surface area of 1028 m2/g. Hydroxyl, methylene, methyl, carboxylic groups and aromatic C=C bonds were some of the several functional groups identified on the its surface. In the catalytic ozonation process, the breakthrough time for the inlet concentration of 200 ppm increased from 36 h for granular activated carbon to 53 h for granular activated carbon ozonation. In other words, the concomitant use of activated carbon and ozone enhanced (from 36 h to 53 h) the removal efficiency of the system by 17 h in comparison with activated carbon alone. In the ozonation process for the bed, the benzene breakthrough time of the bed, for the inlet concentration of 200 ppm, increased from 44 h in the granular activated carbon coated by magnesium oxide system to 78 h in the granular activated carbon coated by magnesium oxide and ozonation. Eventually, the results showed the ozonation process in combination with the granular activated carbon coated by magnesium oxide catalyst.