CO₂ utilization with reject brine using hydrotalcites: Process analysis

CO2 utilization has the potential to support the deployment of CO2 capture technologies through the sale of CO2 based products. In this work, a novel process which combines CO2 utilization with the treatment of reject brines is evaluated. This process makes use of a calcined layered double hydroxide (Mg-Al-O) to remove Cl- from the brine producing an alkaline solution which is then bubbled with CO2 to produce sodium bicarbonate. The Mg-Al-O sorbent is re-generated via a calcination step, in which HCl is generated, permitting its re-use over several cycles. This process holds promise as it is able to address two environmental problems while generating valuable chemical products.