pH电位滴定法测定黄芩苷钴(Ⅱ)配合物的稳定常数  

Determination of stability constant of baicalin-cobalt(Ⅱ)complex by pH potentiometric titration

作　　者：张换平[1] 田大勇[1] 申艳红[1] ZHANG Huan-ping;TIAN Da-yong;SHEN Yan-hong(School of Chemical and Environmental Engineering,Anyang Institute of Technology,Anyang 455000,China)

机构地区：[1]安阳工学院化学与环境工程学院,河南安阳455000

出　　处：《冶金分析》2018年第10期46-50,共5页Metallurgical Analysis

基　　金：国家自然科学基金(U1404217);河南省科技攻关项目(182102310686)

摘　　要：为研究植物对土壤重金属污染进行修复时形成的配合物的稳定性,实验以黄芩苷-钴(Ⅱ)配合物为例进行探讨。在常温常压下,采用pH电位滴定的方法,对黄芩苷与钴离子生成配合物的稳定常数进行了测定。通过使用氢氧化钾标准溶液对一定溶液体系中的黄芩苷溶液及其与钴离子的混合溶液分别进行滴定,借助自动电位数据采集软件记录其反应过程中溶液pH值变化,用生成函数截距法计算出了黄芩苷-Co(Ⅱ)配合物的一级和二级稳定常数分别为lgK_(CoA1)=5.89,lgK_(CoA2)=5.07。通过对黄芩苷-Co(Ⅱ)配合物各物种在不同pH值条件下的分布进行分析可知,在pH>8的环境下,有利于配合物的合成,可为被重金属污染的弱碱性土壤进行修复时采用植物修复技术提供理论依据。The heavy metal-polluted soil can be recovered by plant repairing technique.In order to study the stability of complex formed in this process,the baicalin-cobalt(II)complex was used as an example in experiments.The stability constant of complex formed by baicalin and cobalt ion was determined by pH potentiometric titration at room temperature and atmospheric pressure.The mixture of baicalin solution and cobalt ion in certain solution system was titrated using potassium hydroxide standard solution.The pH change of solution in reaction process was recorded using automatic potential data acquisition software.The first-order and second-order stability constant of baicalin-cobalt(II)complex was calculated by generation function intercept method,respectively,i.e.,lg K CoA1=5.89 and lg K CoA2=5.07.The distribution of various species of baicalin-cobalt(II)complex under different pH conditions was analyzed.It could be found that the environment of pH>8 was advantageous to the synthesis of complex.The study provided theoretical basis for the recovery of weakly alkaline heavy metal-polluted soil by plant repairing technique.

关 键 词：黄芩苷 钴离子 配合物 稳定常数 PH电位滴定法 生成函数法 重金属污染土壤 植物修复技术 

分 类 号：O655.2[理学—分析化学]