Partial desalination of hypersaline brine by lab-scale ion concentration polarization device

In this paper, technical and economic feasibility of partial desalination of hypersaline brine by ion concentration polarization (ICP) desalination is examined. We engineered a lab-scale ICP desalination system producing flow rate up to 96 mL/min, which represents the largest scale-up of ICP desalination process so far. With highly saline brine feed water (NaCl, 70,000 mg/L of TDS) and utilizing two different cation exchange membranes, we measured electrical responses of unit fluidic cell, and monitored the product water salinity changes over a wide ranges of flow velocities and electric current densities. Based on these, realistic power consumption and expected cost of brine treatment can be calculated, for the economic validation of partial brine desalination by ICP process. For the salt removal ratio of 50%, the optimal water cost is obtained as $3.08/m3 while the least power consumption is achieved as 5.6 kWh/m3. Our results also show that the partial desalination could be more economically preferable than complete desalination for the brine management. Yet, ICP desalination should be further improved and optimized, with significant potential to be applied in many different desalination applications and hybrid scenarios.