Modelling of complex reaction-separation processes in a d.c. electric field in microchannels

The paper deals with specific aspects of modelling effects of an electric field applied on microchannels, where also chemical reactions other than dissociation equilibria can take place, and presents three examples of modelling studies that employ software packages developed, in our group. We present a set of mass, charge, momentum and heat balance equations that describe reaction-transport systems and form the core of the specialized program code (1D-IONS) that allows to simulate the spatial evolution of species concentrations and of a variety of electric variables, such as charge density, electric field intensity, and conductivity, in spatially 1D systems for the mixtures of up to 999 components. The output of the program is illustrated by solving the isotachophoretic separation. Based on the same set of fundamental equations the mathematical model of the spatially 2D reacting ionic system was developed to simulate the propagation of reaction fronts in the applied electric field. Modification of the 2D model excluding the assumption of electroneutrality was also developed and used to simulate axial dispersion and mixing in the channel with electroosmotic flows.