A voltammetry procedure with medium exchange for the speciation of heavy metals in wastewater of a sewage treatment plant

摘要

A scheme is proposed for the speciation of heavy metals based on the Nurnberg scheme with two modifications: the application of medium exchange to the anodic stripping voltammetric (ASV) measurement, and the destruction of organic matter and particulate. The protocol is suitable for making operational divisions of four categories for the elements zinc, cadmium, lead and copper in wastewater. Three of these elements can be simultaneously determined by ASV (cadmium is not detected). The parameters of the determination include: electrodeposition potential -1.2 V, time of deaerating 300 s, time of the electrolysis 90 s (with stirring) and the rest time 40 s. Medium exchange is done after the electrodeposition step. We have applied this procedure to the study of metal speciation in effluent from a conventional wastewater treatment plant of the city of Seville (Spain). [References: 14]