Desalination and purification system

摘要

A liquid electrolyte can be desalinated and purified using a system that includes a first electrode and a configuration selected from (a) a second electrode and at least one distinct ion-selective boundary and (b) a second electrode that also serves as the ion-selective boundary. The ion-selective boundary is contained in the liquid conduit adjacent to a porous medium that defines pore channels filled with the liquid and that have a surface charge, and the charge of the ion-selective boundary and the surface charge of the pore channels share the same sign. A liquid including at least one charged species flows through the pore channels, forming a thin diffuse electrochemical double layer at an interface of the liquid and the charged surface of the pore channels. A voltage differential is applied between the electrodes across the porous medium to draw ions in the liquid to the electrodes to produce brine at the electrodes and to create a shock in the dissolved-ion concentration in the bulk volume of the liquid within the pore channels, wherein a depleted zone with a substantially reduced concentration of dissolved ions forms in the liquid bulk volume between the shock and the ion-selective boundary.

主权项

1. A desalination and purification system for a source liquid containing co-ions and counter-ions selected from dissolved ions, charged impurities, charged droplets and combinations thereof, wherein the co-ions and counter-ions have charges of opposite signs, the system comprising:
a conduit for liquid flow including a liquid inlet port, a desalinated/purified liquid outlet port, and a waste liquid outlet port; a first electrode; a second electrode and ion-selective boundary configuration selected from: a) a second electrode and at least one distinct ion-selective boundary, and b) a second electrode that also serves as the ion-selective boundary, wherein the electrodes are configured to drive ionic current in the source liquid when the source liquid fills the conduit and to produce brine/waste liquid from the source liquid, and wherein the ion-selective boundary is configured to conduct the ionic current and selectively transmit or remove the counter-ions and block the co-ions from the source liquid; and at least one porous medium, wherein in configuration “a” the porous medium is on an opposite side of the ion-selective boundary from the second electrode, wherein the porous medium has a surface charge with a sign that is the same as the sign of the co-ions to enable conduction of an additional ionic current via the counter-ions and consequent production of a region of desalinated/purified liquid, wherein the desalinated/purified liquid outlet port is positioned to extract the desalinated/purified liquid from the porous medium, wherein no membrane is positioned in the porous medium to create a separation of liquid flow paths from the liquid inlet port between (i) the desalinated/purified liquid outlet port and (ii) the waste liquid outlet port.