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N,N,N,N-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) is a podand-type ligand with six nitrogen-donors and recognizes the slight difference in the softness between trivalent MA (minor actinides) and Ln (lanthanides).New separating agents, in which TPEN was immobilized chemically in a polymer gel, were synthesized and applied to the separation of MA from Ln.N,N,N,N-tetrakis-(4-propenyloxy-2-pyridylmethyl)ethylenediamine (TPPEN), in which propenyloxy groups were introduced to 4 pyridine rings of TPEN, was used as a crosslinker of acrylic monomers and a copolymer gel with TPPEN and an acrylamide monomer, N-isopropylacrylamide (NIPA), was synthesized.The adsorption of typical trivalent MA, 241Am(Ⅲ) and lanthanide, 152Eu(Ⅲ), into these gels were tested.In a slightly acidic solution at pH5, NIPA-TPPEN gel showed high separation factors of Am(Ⅲ) over Eu(Ⅲ) (SFAm/Eu), which were evaluated to be 26.The adsorbed Am(Ⅲ) was recovered easily in an acidic eluent at pH2.NIPA-TPPEN gel is applicable to the MA/Ln separation process.Thin film of NIPA-TPPEN gel (average thickness : 30-60 nm) was immobilized on the pore surface in porous glass particles and the porous glass particles with NIPA-TPPEN gel were used as a chromatographic agent.The packed column (diameter and height: 1cm) was prepared and the chromatography tests were carried out by a low-acidic solution (pH4) containing Am(Ⅲ) and Eu(Ⅲ).Eu(Ⅲ) was weakly adsorbed and flowed out easily from the column by an eluent of pH4.Am(Ⅲ)was adsorbed selectively at pH4 and recovered completely from the column by changing the pH of the eluent from 4 to 2.In conclusion, the chromatographic agent using NIPA-TPPEN gel is suitable for the extraction chromatographic separation of MA and Ln.Am(Ⅲ) can be recovered from Eu(Ⅲ) by a simple pH swing operation in the pH range of 2 to 4.