Papers by Keyword: Free Chlorine

Abstract: This paper describes the construction of low cost optical fiber sensor for the measurement of free chlorine and also residuals. The granules of poly (norborene) s bound with Cyanuric acid are synthesized as polymer film and applied on glass surface, which is used as sensing membrane. The prepared sensor membrane has a good photochemical stability and it would not leach out by continuous exposure to sample solution. The film is used to measure the changes in the absorbance intensity as a result of reaction between Cyanuric acid and free chlorine. The chlorine is used for the destruction of microbiological pathogens to protect the public health from water-borne diseases. This experiment was conducted for various chlorine samples. The sensor possess good repeatability with the range from 1.0 mg/l to 9.0 mg/l with minimal response time and also shows the characteristics such as reproducibility and stable results for more than 70 samples with a period of 5 days.

Abstract: The water qualities of 5 waterplants were studied by investigating the total bacterial colony, oxygen consumption, free oxygen, and the turbidity. The results showed that the quality of water from ground water in the Industry North Road waterplant is better than those in Yuqing and Quehua which derived from the Yellow River indicated tipical seasonal chang. The quality of the outlet is mainly affected by the quality of raw water. The correlation analysis indicated that total number of colony did not significantly correlated to other indicators.

Abstract: An thin reagent containing optochemical film sensor for detecting and measuring free chlorine in water is described. The film sensor has been manufactured by immobilisation indicator of 3,5-dimethyl-4-hydroxybenzaldazine in a permeable transparent polymeric membrane. A linear calibration for free available chlorine can be obtained in the range between 0.05 and 3ppm. The limit of quantitation is 0.3 ppm, and the accuracy exceeds 7%. It takes about 150s to measure the relatively low occupational exposure concentration of 0.1ppm. The interference of combined chlorine has been studied. The sensor has no response to combined chlorine. And the stability of the sensors and the effect of external parameters like relative humidity (RH), temperature on the sensor response have been investigated. The sensor response is affected by varying the temperature; however, humidity in the range between 0 and 90% RH does not affect sensor response. The 3,5-dimethyl-4-hydroxybenzaldazine remained stable inside the polymeric film and no chemical reaction, crystallization or leaching occurred during 6 months of observation. Proper choice of indicator dye and polymeric material and successful application of kinetic evaluation method for the exposure experiments determine the desired features of the sensor. Introduction