Yuchi A, Sato T, Morimoto Y, Mizuno H, Wada H
Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466, Japan.
Anal Chem. 1997 Aug 1;69(15):2941-4. doi: 10.1021/ac9612685.
The adsorption equilibria of seven trivalent metal ions (M(3+): Sc(3+), Y(3+), La(3+), Fe(3+), Al(3+), Ga(3+), and In(3+)) on chelating resins containing iminodiacetic acid groups (-LH(2)) were studied. Adsorption curves, measured under the conditions of metal ions in excess against chelating groups, directly indicated the metal-to-ligand ratio of the complexes formed in the resin phase. Iron and group 13 metal ions were adsorbed as (-L)(2)HM, while group 3 metal ions were adsorbed as (-L)(3)H(3)M and (-L)(2)HM. The adsorption constants for (-L)(2)HM found for all the metal ions were well correlated with the formation constants of iminodiacetate complexes in aqueous solutions. The actual adsorption of group 3 metal ions was significantly enhanced beyond that expected from this correlation because of the formation of (-L)(3)H(3)M. This is why the selectivity in the adsorption of trivalent metal ions differs from that in the complexation of iminodiacetate in aqueous solutions. The effects of anions and the number of iminodiacetic acid groups per unit weight of resins were also discussed.
研究了七种三价金属离子（M(3+)：Sc(3+)、Y(3+)、La(3+)、Fe(3+)、Al(3+)、Ga(3+)和In(3+)）在含有亚氨基二乙酸基团（-LH(2)）的螯合树脂上的吸附平衡。在金属离子相对于螯合基团过量的条件下测量的吸附曲线，直接表明了在树脂相中形成的配合物的金属与配体的比例。铁和第13族金属离子以(-L)(2)HM的形式被吸附，而第3族金属离子以(-L)(3)H(3)M和(-L)(2)HM的形式被吸附。所有金属离子的(-L)(2)HM的吸附常数与水溶液中亚氨基二乙酸配合物的形成常数有很好的相关性。由于(-L)(3)H(3)M的形成，第3族金属离子的实际吸附比根据这种相关性预期的显著增强。这就是为什么三价金属离子的吸附选择性与水溶液中亚氨基二乙酸配合物形成的选择性不同。还讨论了阴离子的影响以及每单位重量树脂中亚氨基二乙酸基团的数量。
