Desalination now supplies the majority of clean drinking water in areas surrounding the Persian Gulf, but it’s no easy task and can actually make the seawater saltier. Meanwhile, as the oil and natural gas industries have grown in the region, so too has the carbon dioxide saturating the atmosphere. A chemical engineer at Qatar University has been working to solve both problems simultaneously, and an efficient solution has emerged that could change everything.
Farid Benyahia is the man with the plan. The chemist and his research team found a way to recycle waste brine from the process used to turn salty seawater into clean drinking water. The team retooled the 150-year-old chemical conversion method widely used to produce sodium carbonate for industrial applications, simplifying it from seven steps down to just two. Benyahia found that pure carbon dioxide, when mixed with the brine byproduct of desalination in the presence of ammonia, results in solid sodium bicarbonate (baking soda) and ammonium chloride solution. Additional steps break the solution down into calcium chloride solution and ammonia gas, enabling the ammonia to be recycled to start the process all over again.
“The goal is to solve two nasty environmental problems with one smart solution and generate useful, marketable products to offset partially the cost of storing CO2,” Benyahia told Scientific American.
The simplified desalination process recycles waste brine and eliminates the need to flush the super salty solution back into the sea. By finding a way to put excess CO2 to use, Benyahia believes his new method could help offset the emissions created by a growing energy industry. On its own, this process is more expensive than other desalination methods, but capturing and utilizing industrial CO2 outputs could help bring the cost down, if the appropriate infrastructure is in place.