Removal of mercury from water using pottery

Summary

In a previous study, the sorption of radiocobalt by powdered pottery materials was investigated. The use of these materials as immobilization matrix for liquid radioactive waste requires the employment of pottery vessels. Therefore, the present study aims to give detailed investigations of the decontamination of radionuclides and toxic elements using pottery containers. These investigations are equally useful to elucidate how far these vessels can be utilized for water purification through decontamination of toxic and heavy metals.

The radionuclide or heavy metal removal capability using pottery pots, as low cost sorbents, has been investigated for both radioactive (²⁰³Hg) and stable mercury. The results indicated that Hg²⁺ is better removed by pottery from neutral to alkaline solutions. The capacity of the used pottery container (100 ml in volume) for complete removal of mercury was found to reach 3 × 10^-4 mol/l, and the time needed was 8 hours. The sorption process was suggested to occur via adsorption and ion exchange. The effect of presence of humic or fulvic acid, as ligands abundant in water, is also investigated. The results imply that, in absence of humic or fulvic acid the sorption follows the expected behaviour, i.e. sorption sites with similar affinity for mercury. In presence of humic or fulvic acid, additional sorption sites are available by the organic molecule when it is associated to the pottery.