恒电流库仑法测定工业废水中Cr(Ⅵ)的方法研究

Determination of Cr(Ⅵ) Content in Industrial Waste Water with Constant Current Coulometric Method

报道了以Fe(Ⅱ)-Ce(Ⅳ)为双中间体恒电流库仑滴定法测定废水中Cr(Ⅵ)的方法,以平衡电位法指示终点.对影响电流效率的电化学性能、电解液的电极行为及其它影响测定的因素进行了较系统的研究.实验表明,废水中常见离子对测定结果无明显干扰;测定的相对误差<2.0%,回收率为99%～104%.与光度法相比,该法简便、快速、灵敏、准确,且不受试样颜色、混浊度及沉淀的影响,无需配制任何标准溶液,可在同一电解液中连续测定十个以上试样.本法可用于电镀、制革、印染等行业工艺流程及废水中Cr(Ⅵ)的测定.

A new determination method of the content of Cr（Ⅵ） in waste water through dual-intermediate [Fe （Ⅱ）-Ce （Ⅳ）] coulometric method was studied in this paper. The electrolyte was composed of Ce2（SO4）3 , FeNH4（SO4）2, H2SO4 and H3PO4. Balance potential indicated the titration endpoint. The effect of coexisting materials was studied, and they had no apparent disturbance. This method is simple, fast, sensitive and accurate,which is not affected by the color and turbidity of samples. It can be performed without standards, and used for the determination of a series of samples in one electrolyte continuously. This method has been applied to the determination of Cr （Ⅵ） in waste waters from different sources.