Preparation of Chloride Ion Selective Electrode and its Potential Response to Different Chloride Solutions Representing Concrete Environments

Abstract

Ag/AgCl electrode was made from anodized Ag wire and the influence of anodization current density on stability of Ag/AgCl electrode was studied in this paper. Potential response of Ag/AgCl electrode was tested in synthetic concrete pore solutions with different concentrations of chloride ions and influences of sulfate, calcium, potassium and sodium ion on the potential response of Ag/AgCl electrode were also measured. The results show that Ag/AgCl electrode has the best potential stability when it is prepared with 0.4 mA/m2 of current density for 2 hours and there is no measurable potential difference among 20 electrodes prepared with such anodizing condition. The potential of Ag/AgCl electrode develops to a constant value in less than 60 seconds and maintains stable during the test period when immersed into synthetic concrete pore solution with different amount of chlorides. Ag/AgCl electrode shows a good linear potential response to a wide range of chloride concentrations from 0.005 to 1.0 M. Sulfate, calcium and sodium ions show inconsiderable influences on the potential of Ag/AgCl electrode. Therefore, it is suggested that Ag/AgCl electrodes can be used as chloride sensors in concrete exposed to different environments.