Effect of pH on Stability Constants of Sr(II)-Humate Complexes
Effect of pH on Stability Constants of Sr(II)-Humate Complexes
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pH 对 Sr(II)-腐植酸盐配合物稳定性常数的影响
DOI：
10.3327/jnst.35.579
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
H. Ohashi
中科院分区：
文献类型：
--
作者：
M. Samadfam;T. Jintoku;Seichi Sato;H. Ohashi
本文用透析法测定了298 K、N_2气氛下，在0.1mol/dm ~ 3（NaClO_4）、pH = 4 ~ 10范围内，Sr（Ⅱ）与腐殖酸（HA）络合的表观稳定常数β。发现log β随pH增加，从pH 4.0时的2.5增加到pH 10.0时的4.1。log β在较高pH值下趋于稳定，表明达到饱和。此外，发现表观配体与金属的比率为1.15±0.10。HA的羧基和酚基随pH的变化可能是引起稳定常数变化的主要因素。
The apparent stability constant, β, for the complexation of Sr(II) with humic acid (HA) was determined by a dialysis method in the pH range horn 4 to 10 at the ionic strength of 0.1mol/dm3 (NaClO4) at 298K under N2 atmosphere. It was found that log β increased with pH from 2.5 at pH 4.0 to 4.1 at pH 10.0. The log β tended to level off at higher pHs, indicating that saturation was being reached. Further, the apparent ligand to metal ratio was found to be 1.15±0.10. Dissociation of carboxylic and phenolic groups of HA with pH is probably the main factor that gives rise to the changes in stability constants.