Removal of Phthalic Acid Esters from Aqueous Solution by Inclusion and Adsorption on β-Cyclodextrin

Removal of phthalic acid esters (PAEs) by the formation of inclusion complexes with β-cyclodextrin (β-CD) in aqueous solution was studied. According to the measure ments of fluorescence and NMR spectroscopy, it was confirmed that PAEs were included into the β-CD cavity. The stability constants of the β-CDPAE complexes were varied depending on the alkyl chain length of the PAEs. The adsorption isotherms of PAEs and β-CD polymer (β-CDP) were well described by Freundlich isotherm equations, and the adsorption capacity varied according to the stability constant. PAEs were well adsorbed by β-CDP both in batch and in a column system, and the PAEs were also released from β-CDP by shaking with a mixture of methanol and water. The recovery efficiency was varied with the mixture ratio of methanol and water, and the recovered β-CDP was reusable as an adsorbent.