Abstract
The objective of this study is to clarify the effects of coexistent substances in landfill leachate in the following processes: the adsorption of 2,4-dichlorophenol (2,4-DCP) from landfill leachate using different adsorbents, the extraction of 2,4-DCP from adsorbents using acetic acid, and the decomposition of 2,4-DCP by ozonation in acetic acid. The adsorption capacities of all adsorbents for 2,4-DCP in landfill leachate were almost the same as that of 2,4-DCP dissolved in distilled water. The adsorption capacities of granular activated carbon (GAC) and SP207 (bromine-bonded styrene-divinyl benzene-type adsorbent) immersed in landfill leachate for 6 months (immersed adsorbents) were almost the same as those of the new GAC and SP207. On the other hand, the amount of adsorbed 2,4-DCP on immersed SP850 (styrene-divinyl benzene-type adsorbent) at an equilibrium concentration of 1 μg·l-1 2,4-DCP was only 74% of the new SP850. After several adsorption-extraction processes, the adsorption capacities for 2,4-DCP of all immersed adsorbents became constant and 2,4-DCP adsorbed on immersed adsorbents was completely extracted by acetic acid. This suggests that immersed adsorbents regenerated by acetic acid can be used repeatedly. The decomposition rate of 2,4-DCP by ozone in acetic acid after the submersion of immersed GAC was higher than that in the new acetic acid. Organic compounds and Fe3+ present in landfill leachate enhanced the decomposition rate of 2,4-DCP by ozonation in acetic acid.
