Redox Sensors for the Control of Process and Waste Waters

摘要

The state of waste and process water depending on the particular application can be characterised by quantitative analysis of its composition (e.g., heavy metal ions, nitrate or phosphate) but often, at least in a complementary manner, by determinating of non-specific parameters like electrolytic conductivity or redox potential. The latter is usually measured potentiometrically using indicator electrodes of precious metals. However, their application is connected with measurement errors caused by interactions between the media and the noble metal surfaces. Specifically this problem occurs in real media that can be found in process chemistry and in waste water sector, for example. Using electron conducting glass instead of noble metal membranes in potentiometric redox electrodes solves this problem. We present possibilities for their fabrication and results from their use.