A process for combined CO2 utilization and treatment of desalination reject brine

Abstract

One of the problems facing the desalination industry is the management of concentrated brine wastes which constitute an environmental pollution when disposed into surface water bodies. This problem is huge in regions where desalination is heavily relied upon for potable water. In this work, a process is proposed for the first time, which could make these brines safer for disposal in combination with CO2 capture and utilization for the production of chemicals like NaHCO3. Revenues from the sale of this product could offset some of the high costs which have hampered the growth of Carbon Capture, Utilization and Storage (CCUS) technology. As such, the process tackles two environmental problems while generating a valuable product. Results of the process evaluation are promising on account of the high CO2 absorption capacity of about, 1.86 mol CO2/kg carbonated solution, NaHCO3 yield of 44 g/kg carbonated solution, and a 70% and 20% overall reduction in the brine chloride and sodium concentration respectively, making it much less saline and safer to dispose into the sea.