Many municipalities use chlorine as disinfectant. Its concentration is maintained at around 2 ppm to ensure anti-bacterial activity while minimizing any undesirable effect on the water user. Free-chlorine monitoring is therefore critically important. Currently free chlorine monitoring instruments are expensive and can only be used by trained operators. This is not always feasible in remote communities. We propose low-cost graphite based sensor to meet this need. Pencil lead was electrochemically modified and used to detect and measure free chlorine concentration in water samples by chronoamperometry. The signal was linear in the pertinent concentration range. The results correlated well with those obtained using a commercial instrument. Performance parameters such as noise, response time, hysteresis, stability after storage, reusability were evaluated. Advantages, disadvantages and prospect for future work are discussed.

Low-cost free-chlorine sensor

251st National Meeting (2016)

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