Promoting mercury removal in high humidity environments by hydrophobic modified activated carbon with methyl functional group.

The HO content in the flue gas seriously inhibits the application of activated carbon injection adsorption mercury technology. Hydrophobic activated carbon was prepared by hexamethyldisiloxane (HMDSO) vapour deposition, the contact angle of water for hydrophobically modified AC increased from 42° to 143°, and HO adsorption capacity decreased from 17.28 mg/g to 3.05 mg/g when relative humidity was 95%. The simulation results of water channels show that the number of water molecules escaping from the modified AC loaded with hydrophobic functional groups increased by 325%. When the water vapour content was 30%, the mercury removal efficiency of modified AC increased from 58.82% to 89.60% compared with AC, and the adsorption capacity increased by 10.6 μg/g. In high-humidity environments, NO and SO can produce corresponding acids for oxidising Hg, thereby enhancing the adsorption efficiency of Hg, while NH completes with Hg for the active sites on the surface of AC, which has an inhibitory effect.