Mathematical modelling and optimisation of a coulometric sensor-actuator system based on three-dimensional diffusion

Abstract

A mathematical model describing the processes taking place in a measuring cell with a coulometric sensor-actuator system was developed both for the cases of titration of strong and weak protolytes. It takes into consideration the three dimensional diffusion which occurs in the volume of the measuring cell. The boundary conditions express the fact that the walls of the measuring cell are impermeable to the chemical species participating in the protolytic interactions and that a constant current is applied at the actuator electrode. The model was numerically solved by the implicit alternating-direction finite-difference method. Experimental titration of diluted solution of nitric, acetic and b..