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采用萃取法研究了不同ｐＨ值的０．１ｍｏｌ／ｋｇＮａＣｌＯ４溶液中，Ａｍ（Ⅲ）与腐殖酸的配位行为。实验结果表明，Ａｍ（Ⅲ）－腐殖酸配合物的累积稳定常数与溶液ｐＨ值有关，配位比为１∶２。不同ｐＨ值条件下，Ａｍ（Ⅲ）与腐殖酸配合物的累积稳定常数为：ｌｇβ１＝６．５６±０．０５，ｌｇβ２＝１０．７７±０．１３（ｐＨ＝４．０）；ｌｇβ１＝７．９４±０．１１，ｌｇβ２＝１１．８０±０．２１（ｐＨ＝５．０）；ｌｇβ１＝１０．７４±０．２８，ｌｇβ２＝１２．８８±０．４９（ｐＨ＝６．０）；ｌｇβ１＝１２．８５±０．３０，ｌｇβ２＝１４．８０±０．６２（ｐＨ＝７．０）；ｌｇβ１＝１４．８８±０．４８，ｌｇβ２＝１５．６５±０．６９（ｐＨ＝８．０）；ｐＨ值的变化与Ａｍ（Ⅲ）－腐殖酸配合物累积稳定常数间的关系为：ｌｇβ１＝２．１６（±０．９８）ｐＨ－２．３４（±０．９３），ｌｇβ２＝１．２８（±１．０４）ｐＨ＋５．５２（±１．２１）。
The complexation of Am (Ⅲ) with humic acid in 0.1 mol / kg NaCl solution with different pH values was studied by extraction method. The experimental results show that the cumulative stability constant of Am (Ⅲ) - humic acid complex is related to the solution pH, and the coordination ratio is 1: 2. Under different pH conditions, the cumulative stability constants of Am (Ⅲ) and humic acid complexes were: lgβ1 = 6.56 ± 0.05, lgβ2 = 10.77 ± 0.13 (pH = 4.0) = 7.94 ± 0.11, lgβ2 = 11.80 ± 0.21 (pH = 5.0); lgβ1 = 10.74 ± 0.28, lgβ2 = 12.88 ± 0.49 (pH = 6). Lgβ1 = 12.85 ± 0.30, lgβ2 = 14.80 ± 0.62 (pH = 7.0); lgβ1 = 14.88 ± 0.48, lgβ2 = 15.65 ± 0.69 ( pH = 8.0). The relationship between the change of pH value and the cumulative stability constant of Am (Ⅲ) - humic acid complex was: lgβ1 = 2.16 (± 0.98) pH-2.34 (± 0. 93), lgβ2 = 1.28 (± 1.04) pH + 5.52 (± 1.21).