天然水体铜络合容量的测定与调查

Determination and Survey of Cu Complex Capacity in Natural Water

天然水体中存在的络合配位体与受纳的重金属污染物能产生一定的络合反应 ,改变重金属的形态 ,可以减低对水生动植物的毒性。通常可以用络合容量 (Complexcapacity)来表示天然水体的这一特性 ,它实际上表示水体中络合配位体 (有机的或无机的 )含量的多少 ,通过测定络合容量 ,可以了解水体对重金属的自净能力 ,对研究重金属在纳污水体中的迁移有实际意义。文章用铜标准溶液滴定待测水样 ,结合在线富集 FAAS测试技术 ,求得天然水体中有机和无机配体的络合容量和条件稳定常数 ,并对常量干扰因素的影响进行了检验。结果表明 ,水体pH 5 0～ 9 0范围内 ,对络合容量测定无显著干扰。Cl-,SO2 -4,HCO-3 以及OH-可与Cu2 + 形成各种无机络合态铜 ,样品回收率为 98 0 % ,测定络合容量的相对标准偏差为 4 9% ,条件稳定常数的相对标准偏差为 8 4 %。此外 ,还调查了济南卧虎山水库络合容量的水平和垂向分布特征 ,并探讨了络合容量与水质指标化学需氧量、叶绿素a的相关关系 ,水样pH太低 ,有机络合态铜解离 ,宜造成结果偏低。

The complex ligand can produce some complex reactions with heavy metal pollutant accepted in the natural water. Changing the morphology can reduce the toxicity of aquatic organisms. Usually, the characteristic can be expressed with the complex capacity. In fact, it expresses the content of the complex ligand (organic or inorganic), and can be used to understand the self-purification capacity of the natural water. There is an actual meaning in studying the heavy metal migration in the pollution water. In this paper, we titrated the water samples for determination with Cu standard solutions. We obtained the complex capacities of organic ligands or inorganic ligands and condition stability constants in the natural water by flame atomic absorption spectrometry coupled with on-line flow. We tested the influences of normal interferon. The result showed that it had no significance influences on the determination of Cu complex capacity with pH 5.0-9.0 in the natural water. The Cl-, SO42-, HCO3- and OH- could form inorganic ligands Cu. The recovery rate was 98.0%. The relative deviation for the determination of complex capacity was 4.9%. The relative deviation of condition stability constants was 8.4%. In addition, we surveyed the level and vertical distribution characteristics of the ligand in Jinan Wohushan reservoir, and studied the correlation of COD and chlorophyll with the complex capacities. If the pH was low, the organic Cu complex ligands could ionize, and the result was low.