Abstract
Magnesium-based and calcium based compounds have been expected as adsorbents for arsenic removal from contaminated water. However, the adsorbents which have been used to purify arsenic contaminated water would contain a large amount of arsenic. If the spent adsorbents were dumped into environment without an appropriate treatment, a secondary environmental pollution might be caused by leaching of arsenic from the spent adsorbents. Therefore, it is necessary to evaluate environmental stabilities of the spent adsorbents.
In this study, the soil leaching tests on the spent magnesium-based and calcium-based adsorbents were conducted and the experimental data obtained were examined. From the results, the magnesium-based and calcium-based oxides and hydroxides were found to have higher environmental stability. In addition, in terms of secondary environmental pollution by leaching of arsenic from the spent adsorbents, the risk of the spent MgO-based adsorbent was illustrated to be the lowest among those of the tested adsorbents. On the other hand, the spent MgCO3-based adsorbents showed considerably lower environmental stabilities and higher risks especially when those were dumped in sandy soils.
