交流示波极谱滴定法测定废电镀液中的银

Determination of silver in spent electroplating bath by a.c. oscillopolarographic titration

采用交流示波滴定法 ,以二乙基二硫代氨基甲酸钠为滴定剂 ,稀硝酸为解蔽剂 ,乙酸钠和聚乙烯醇为极谱底液测定废电镀液中的银含量。讨论了聚乙烯醇、乙酸钠、滴定剂、pH值和仪器等因素对测定结果的影响。该方法误差小 ,银回收率为97 50 %～ 1 0 1 2 5% 。

Silver in spent cyanide electroplating bath was determined by a.c. oscillopolarographic titration with sodium diethyl dithiocarbamate as titrant, dilute nitric acid as demasking agent, and sodium acetate and polyvinyl alcohol as base solution. The effect of polyvinyl alcohol, sodium acetate, titrant, pH value and measuring instrument on the measured results was discussed. This method has low error, silver recovery is 97 50%～101 25%, which meets the requirements of silver determination in spent electroplating baths.