Wireless desalination using inductively powered porous carbon electrodes

Abstract

Water desalination by capacitive deionization (CDI) uses electrochemical cell pairs formed of porous carbon electrodes, which are brought in contact with the water that must be desalinated. Upon applying a cell voltage or current between the electrodes, ions are electrosorbed and water is produced of a reduced salinity. Such cells are directly connected to the electrical circuit via current collectors and wires. In this work we demonstrate for the first time wireless desalination by porous carbon electrode cells. Here, the cells are charged, at constant current, by wireless energy transfer via the mechanism of resonant inductive coupling (RIC) by the use of an external transmitting coil that induces a magnetic field which is picked up by an energy receiving circuit which charges the electrodes one relative to the other. We present data for wireless power transfer, for charge transfer between one electrode and the other, and desalination degree, at various levels of the maximum cell voltage in cycles of a typical duration of a few minutes. In the present work, one wireless desalination cell is placed within the transmitting coil, with the two porous electrodes placed parallel. A future design may use optimized spherical desalination capsules, placed in a packed bed or continuous fluidized bed water desalination reactor.