Abstract

Fresh water deficiency caused by climate change calls for employing novel measures to ensure safety of drinking water supply. Wireless sensor networks can be used for monitoring hydrological conditions across wide area, allowing flow forecasting and early detection of pollutants. While there are no fundamental technological obstacles to implementation of large area sensor networks, their feasibility is constrained by unit cost of sensing nodes. This paper describes a low-cost pH sensor, intended for use in fresh water monitoring. The sensor was fabricated in a standard thick film process, and an off-the-shelf resistive paste was used as a sensing material. For the fabrication of sensor, RuO2 resistive paste was screen printed on the alumina substrate with silver conducting layer. Test solutions with pH ranging from 2 to 10 were prepared from HCl or KOH solutions. The potential difference between reference and sensing electrode (electromotive force emf of an electrochemical cell) should be proportional to the pH of a solution according to the Nernst equation. The fabricated sensor exhibits Nernstian response to pH. Influence of storage conditions on sensing performance was also investigated.

Highlights

  • Prevention of water pollution is one of the major issues in global environmental protection system

  • Researchers have been trying for a long time to overcome these problems and develop a new pH measurement system which could be helpful for making a new generation of wireless pH sensors for online monitoring of water quality [1,2,13,14]

  • As compared to other pH sensitive solid state materials, RuO2 exhibits excellent sensitivity, close to the Nernstain response in a wide pH range, high accuracy and lower susceptibility to interferences caused by other ions dissolved in water [2]

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Summary

Introduction

Prevention of water pollution is one of the major issues in global environmental protection system. As compared to other pH sensitive solid state materials, RuO2 exhibits excellent sensitivity, close to the Nernstain response in a wide pH range, high accuracy and lower susceptibility to interferences caused by other ions dissolved in water [2]. It is considered as a promising material for fabricating pH and dissolved oxygen sensors. An insulating layer (polyurethane resin) was painted on the surface of the sensor, except the sensitive area which will be in contact with the solution and the pad for electrical contact. The compositions of the layers were analyzed by Energy Dispersive Spectroscopy (EDS) method (EDAX EDS System Genesis Software)

Results and Discussion
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Conclusion
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