Achieving High-Quality Freshwater from a Self-Sustainable Integrated Solar Redox-Flow Desalination Device

Solar-assisted electrochemical desalination has offered a new energy–water nexus technology for sustainable development in recent studies. However, only a few reports have demonstrated insufficient photocurrent, a low salt removal rate, and poor stability. In this study, a high-quality freshwater level of 5–10 ppm (from an initial feed of 10 000 ppm), an enhanced salt removal rate (217.8 µg cm −2 min −1 of NaCl), and improved cycling and long-term stability are achieved by integrating dye-sensitized solar cells (DSSCs) and redox-flow desalination (RFD) under light irradiation without additional electrical energy consumption. The DSSC redox electrolyte (I − /I 3 − ) is circulated between the photoanode (N719/TiO 2 ) and intermediate electrode (graphite paper). Two DSSCs in parallel or series connections are directly coupled to the RFD device. Overall, this hybrid system can be used to boost photo electrochemical desalination technology. The energy–water nexus technology will open a new route for dual-role devices with photodesalination functions without energy consumption and solar-to-electricity generation.