Numerical simulation of fluid flow and desalination effects in ceramic membrane channels

Abstract

Ceramic membranes have been used in the pretreatment of seawater desalination, but few studies investigate the desalination by ceramic membranes. In this paper, we establish a hydrodynamic model of a ceramic membrane channel to study the influencing factors of fluid flow and desalination efficiency in membrane nanochannels. A complex model that characterizes the tortuosity and nonuniformity of the membrane channel with pores and throats is established. The effects of pore diameter, pore-to-throat ratio, slip distance, applied potential, ionic charge number and transmembrane pressure (TMP) on the fluid flow and the desalination efficiency are analyzed. Simulation shows that the zeta potential of the membrane material generates an electric potential in the membrane channel, which causes the ceramic membrane to adsorb anions and repel cations, producing a desalination effect. Meanwhile, the application of external potential enhances the desalination effect. Effects of the above six parameters on the desalination are compared quantitatively. The maximum desalination rate of 85.7% is achieved when E = 150 mV, d = 40 nm, and TMP = 40 kPa. The flow model and simulation results demonstrated in this study provide important guidance for the further development and industrialization of desalination technology using ceramic membranes.