Photoelectrochemical Treatment of Reject Brines from RO Plants

Water scarcity issues have forced nations to find new approaches to meet growing water demands. Most often, this involves harvesting lower quality or impaired water supplies as a source for drinking water.  For example, in sea water desalination along coastal communities and in land-locked urban centers there is growing reliance of wastewater recycling. Desalination techniques, such as Reverse Osmosis, are used to restore municipal and industrial wastewater to a quality suitable for beneficial reuse (including drinking).  This method to produce high quality water is energy intensive and produces large volumes of concentrated brine that challenge the widespread implementation of such technologies.  Here we report a photoelectrochemical process that is built on established chloralkali processes to explore alternative systems. In doing so we address important fundamental questions on water desalination using sunlight while also pointing to near-horizon applications in solar energy conversion.