Adsorption of nickel and mercury from drinking water simulant by activated carbon

The removal of nickel and mercury from drinking water, using powdered activated carbon (PAC) and granular activated carbon (GAC) was studied intensively. The water studied was artificially contaminated by Ni and Hg to yield 2mg/l each. Both batch and continuous systems were tested. The time needed to maintain equilibrium and the adsorption isotherm were determined by the batch system. The results obtained were found to be confirmed with Freundlich’s equation, rather than Langmuir or BET. When the PAC was used, the values 1/n and K were 1.59 and 1.02 for Ni and 1.21 and 1.91 for Hg. Relatively similar results were obtained when the GAC was examined. This indicated the stronger adsorbability of mercury compared to nickel. When investigating the continuous system at different contact times the results indicated that increasing the contact time increased the metal : carbon removal efficiency. The overall results showed that the breakthrough points for either Ni or Hg reflected their adsorption isotherms as indicated by k values. Concludes that the addition of an activated carbon filter is recommended for the treatment of drinking water contaminated by heavy metals.