From 35 g/L to 3.5 g/L NaCl in one cycle of desalination
From 3.5 g/L
to <0.6 g/L NaCl
in one cycle of desalination
The CowaTech technology has demonstrated facile desalination catalyzed by carbon dioxide and promoted by CO2-responsive diamine, which can dynamically self-aggregate and co-precipitate with NaCl from aqueous media, completing desalination.
Scroll down for a simplified schematic illustration of the technology.
The CO2-mediated desalination using diamine is conducted using a general method where alkyl chain-modified diamine is treated with CO2 in saline water or seawater. Upon the spontaneous formation of carbamate or bicarbonate, or carbonate salt of ammonium cation, the CO2-responsive unit is now activated to chelate NaCl (or salt).
These ion-ion interactions can now trigger self-aggregation of the molecular unit by taking advantage of ion alkyl chain induced by Van der Waals forces. The outer sphere of the obtained high molecular weight supramolecular network is presumably hydrophobic, therefore, exhibit low solubility in aqueous solutions.
The spontaneous precipitation occurs within 60-120 seconds, where the separation can be performed to provide salinity-reduced water (from high and low concentrations).
After desalination has taken place and the desalinated water is decanted, the diamine can be regenerated and reused for new cycles of desalination.
The used CO2 can also be collected for storage or used in the next round of desalina-tion. In addition, the precipitated NaCl can be collected and reused for other purposes.
The energy consumption for the entire process is expected to be well below 0.5 kWh/m3 of desalinated water produced and thus considerably more energy-efficient than today’s state-of-the-art technologies.
Currently, the CowaTech technology is at technology readiness level (TRL) 2-3.