Inhomogeneous thermal effect on ion transport in charged nanochannel

A better understanding of the coupled thermal electrokinetic chemical transport process has significant impact on the microfluidic systems or the electrochemical systems. In the case where the concentration gradient and temperature gradient fields are applied simultaneously, it is difficult to investigate the mechanism of ion electrokinetic transport within the nanopores by experiment. Therefore, in this study, we use the pore-scale simulation by lattice Boltzmann method on GPU to investigate this coupled ion transport process in a nanochannel. The results show that the Soret effect has little contribution to the ionic flux changes in the nanochannel as apply different external temperature gradients. The essential cause to change the ionic flux is the inhomogeneous charged liquid-solid interfaces of the nanochannel induced by the temperature gradient. The inhomogeneous charged interface causes various electrical potential distributions, which also induces the changes of ion concentration distributions. These inhomogeneous distributions of potential and concentration lead the alteration of the diffusion and electromigration. This investigation could improve the understanding of thermal electrokinetic chemical coupled ion transport in the nanochannel.