Evaluation of electro-osmotic pumping effect on microporous media flow

In this paper, the electro-osmotic flow (EOF) in micro-porous media is investigated regarding to the flow rate caused by the combined effect of electro-osmosis force and the gravitational force. It is noticeable that the actual electro-osmosis pumping force can be achieved at flow rate of 10 μL/min in our designed system. With a constant external DC electric field supplied, in which the external electric field exerts the same effect of voltage density on the whole particle interface, the flow resistance inside the pores deceases when water entering into the electro-osmosis pumping section. Moreover, the mass flow rate by the effect of electro-osmosis pumping can be achieved at 1.49 × 10−4 g/s under 5 V DC supply. To simplify the practical flow pattern in the micro-porous media, a specific micro-channel is assumed with a compact spherical stacking-up model. To simulate this geometrical model, a modified lattice Boltzmann method is set up in order to form the electro-osmotic flow of a practical problem from our experiment. The numerical results are obtained and analysed for fitting the present model with the micro-porous media. Both the experimental and numerical results have provided some useful instructions of electro-osmosis performance for designing micro-porous channels in such as filtering the compounds of drug delivery, particle purification and liquid separation applications etc.