Sensors for Environmental Monitoring

Chlorination of water supplies has been responsible for saving millions of lives previously lost to diseases such as cholera and typhoid since it was introduced in 1908. To maintain safe levels of chlorine, monitoring of water supplies must be carried out.

Currently there are two main methods of measuring chlorine concentrations. A colorimetric method using the DPD reagent can be performed both manually and automatically. Alternatively, electrochemical sensors can be used to continuously monitor chlorine concentrations. Both methods require regular top-ups of reagents and maintenance and hence are costly to keep running.

We propose to study an alternative optical measurement method that does not require reagents and hence will reduce cost. This method will rely on the large change in refractive index that occurs when chlorine reacts reversibly with isocyanuric acid. The project will study methods of immobilising isocyanuric acid in suitable matrices, deposition of these chlorine sensing materials on suitable substrates and the sensitivity, limit of detection and longevity of such sensors.