Activated Carbon Adsorption of Mercury

At lower pH (pH = 4), the removal of mercury involved physical adsorption or reduction of Hg(II) in addition to the above chemisorption process. The pH of the aqueous solution was also found to have a profound influence on the amount of Hg(II) adsorption by an activated carbon. The adsorption was several times more at 

FIGURE 6.16 Effect of sulfur content in carbon on the removal of mercury vapors from air. (Source Sinha, R.K. and Walker, P.L., Jr., Carbon, 10, 754, 1972. With permission.) 

FIGURE 6.17 Removal of mercury as a function of carbon content at different pH values. (Source Thiem, L., Badorek, D., and O Conner, J.T., 7. Am. Water Works Assoc., 68, 447, 1997. With permission.) 

In the case of the sulfurized carbon samples also, the reduction of Hg(II) into Hg(I) enhances the adsorption of Hg(II) ions. The observations and the postulations made by Lopez-Gonzalez et al. in respect of the decrease in adsorption of Hg(II) ions on oxidation with H2O2 and the increase in adsorption of Hg(II) ions at higher pH values, appear to be contrary to the general behavior of oxidized carbons that 

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