Preparation and Properties of Solid-state Chloride Ion Selective Electrode for Detecting Chloride Ions in Concrete

Abstract

An all solid-state and roll-shape Ag/Ag Cl electrode for detecting chloride ions in concrete was prepared by electrochemical oxidation of high purity(99.99%) silver foil. Electrochemical measurement results indicate that in comparison with the conventional powder moulding Ag/Ag Cl electrode, the novel chloride ion selective electrode has a larger exchange current density, higher specific surface area and lower temperature coefficient; by means of the electrode a better linearity is revealed of the potential response slope(-58.2 m V) versus Cl-concentration in an artificial pore solution of concrete, which is close to the theoretical value; besides, the novel electrode also exhibits a rather stable potential for a period of 230 d with fluctuations less than 4 m V. The experimental results in concrete shows that the performance of the all solid-state and roll-shape electrode, such as its linearity of potential response to lg[Cl-] and anti- interfere capability can significantly be improved by wrapping the electrode with a thin film of polyvinyl alcohol gel electrolyte. The mor-phology observation reveals that the novel Ag/Ag Cl electrode has a higher active surface area,which may be beneficial to the stability and the sensitivity of ion selection. In addition, the close stacked and layer by layer structure of the all solid-state and roll-shape Ag Cl/Ag electrode also enhances the adhesion of Ag Cl particulates to the Ag foil, which further improves its reliability on chloride detection and its service life in concrete.