聚(N-羧乙基乙烯亚胺)与重金属离子的配位性能评价

EVALUATION OF CHELATING ABILITY OF POLY(NCARBOXYETHYLETHYLENIMINE) WITH SOME HEAVY METAL IONS

运用两种改良的Ｂｊｅｒｒｕｍ方法对聚（Ｎ－羧乙基乙烯亚胺）（ｐｏｌｙ（Ｎ－ｃａｒｂｏｘｙｅｔｈｙｌｅｔｈｙｌｅｎｉｍｉｎｅ），ＰＣＥＩ）与重金属离子Ｃｏ２＋，Ｎｉ２＋，Ｃｕ２＋，Ｃｄ２＋，Ｚｎ２＋的配位稳定性能进行了评价．通过连续变动法确定了配位物的组成．这几种重金属离子与ＰＣＥＩ的配位逐次稳定常数均为ｌｇｋ１＞ｌｇｋ２＞ｌｇｋ３＞ｌｇｋ４，配位稳定次序为Ｎｉ２＋＞Ｃｏ２＋～Ｚｎ２＋＞Ｃｄ２＋．ＰＣＥＩ与重金属离子的配位在大分子内进行，与Ｃｕ２＋，Ｃｄ２＋，Ｚｎ２＋的配位数为４．

おwo modified Bjerrum methods were used to evaluate chelating properties of poly(Ncarboxyethyl ethylenimine) (PCEI) with heavy metal ions——Co2+, Ni2+, Cd2+, Cu2+, Zn2+. The complex structures of PCEI with these metal ions in aqueous solution were determined by Job′s continuous variation analysis. For every metal ion, the successive stability constants follow this order: lgk1>lgk2>lgk3>lgk4. The chelating ability of metal ions with PCEI was thought to be: Ni2+>Co2+～Zn2+>Cd2+. The chelates of PCEI with metal ions formed intramolecularly and ligand number with Cu2+, Ni2+, Cd2+ was four.