A Pretreatment Method for Detection of Cyanide Ion Concentration in Decontamination Wastewater

Abstract

Three oxidant decontaminants, including NaClO, H2O2 and an organic peroxyl acid, were introduced to destroy the cyanide ion. The residual cyanide ion concentrations in different decontamination water were detected by a cyanide ion selective meter. Before the detection process, the oxidants left in the cyanide decontamination water were pretreated by adding a certain amount of Na2SO3. Results showed that starch-iodide solution indicator method presented a perfect function on determining the dosage of Na2SO3. Values of the relative mean deviations on residual cyanide detection were below 5%. After the decontamination water was deoxidized by Na2SO3, whether the sample distillated or not could not affect the value of CN- quite much. Non-distillation was confirmed alternative in the detection of cyanide ion decontamination water. Too much standing time would lead to a relatively lower CN- concentration, especially in that of non-distillation.