研究报告
翟羽佳,王建铎,王思达,王洪杰.腐殖酸与镉离子在水合二氧化锰表面的分配系数研究[J].环境科学学报,2015,35(10):3144-3150
腐殖酸与镉离子在水合二氧化锰表面的分配系数研究
- Study on the distribution coefficients of humic acid and cadmium ions on the surface of hydrous manganese dioxides
- 基金项目：国家水体污染控制与治理科技重大专项(No.2015ZX07204-002);国家自然科学基金(No. 51278051)
- 作者
- 单位
- 翟羽佳
- 北京林业大学环境科学与工程学院, 北京 100083
- 王建铎
- 北京城建设计发展集团股份有限公司, 北京 100037
- 王思达
- 中国科学院生态环境研究中心环境水质学国家重点实验室, 北京 100085
- 王洪杰
- 北京林业大学环境科学与工程学院, 北京 100083
- 摘要：水体中腐殖酸(HA)和金属离子广泛存在,二者的相互作用对其在水中天然矿物颗粒表面的吸附、降解等环境行为具有重要影响.本文采用离子交换平衡法测定了HA和镉离子(Cd(Ⅱ))的配位数(co-ordination number, x)和络合稳定常数(complex stability constant, K),系统考察了pH值和离子强度对x和K的影响,并研究了HA和Cd(Ⅱ)在水合二氧化锰(HMO)表面的分配关系.结果表明:pH值对HA和Cd(Ⅱ)的配位数影响较小(x=1.651~1.752),而对络合稳定常数影响显著(logK=1.652~3.548);在不同pH值条件下,离子强度对HA和Cd(Ⅱ)的络合稳定常数影响均较小,而其配位数均随溶液离子强度的增加而提高;不同温度条件下,HA-Cd(Ⅱ)络合物在HMO表面的分配系数(Kd)均低于HA和Cd(Ⅱ)在HMO表面的分配系数,表明HA-Cd(Ⅱ)络合体系的存在抑制了HMO对Cd(Ⅱ) 和HA的去除作用.
- Abstract：Humic acid (HA) and metal ions are widely distributed in natural water. The environmental behaviors, such as the adsorption or degradation of the pollutants on the surface of the natural mineral particles, are obviously affected by the co-relationship between the pollutants. In the present study, the complex stability constant (K) and co-ordination number (x) of HA and cadmium ions (Cd(Ⅱ)) at different pH and ionic strength are caculated according to the results of cation-exchange equilibrium method. Meanwhile, the distribution relationship between HA and Cd (Ⅱ) on hydrous manganese dioxides (HMO) is also studied. The pH of the solution has little effect on the values of x (x=1.651~1.752), but has significant effect on the values of K (logK=1.652~3.548). The ionic strength of the solution has no clear influence on the values of K, while the values of x increase with the enhancement of the ionic strength. At different temperatures, the values of the distribution coefficient (Kd) of HA-Cd (Ⅱ) complex on the surface of the HMO are obviously lower than that of the HA or Cd (Ⅱ), indicating that the complexation of the HA and Cd (Ⅱ) impedes the removal of HA and Cd (Ⅱ) by HMO.
- Key words：humic acid Cd(Ⅱ) HMO co-ordination number complex stability constant distribution relationship
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