埋立地浸出水中に存在する2,4-ジクロロフェノールの吸着剤を介した有機溶媒中への濃縮とオゾン処理における共存物質の影響

抄録

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.