Member Companies


Greentown Alumni

About the Company

Capture6 aims to affordably remove carbon from the atmosphere using renewable energy while increasing clean water supply. Its process takes salt water and makes sodium hydroxide for use as a solvent for capture of CO2 from the atmosphere. This brine is treated and cleaned, returning up to 75 percent back as freshwater. The carbonates can be reused, contributing to the circular economy and industrial decarbonization, or stored, permanently removing ambient CO2.

About the Solution

Capture6’s basic fundamental operating principles focus on affordability, scalability, and rapid deployment of direct air capture solutions while generating climate adaptation and mitigation benefits. The Capture6 process starts with waste brine from desalination and water recycling facilities. The brine is then processed using nanofiltration, ion exchange, reverse osmosis, and electrodialysis with bipolar membranes (EDBM). During EDBM, the brine passes through membranes under a direct current and is separated into NaOH and HCl. The NaOH solvent then reacts with atmospheric CO2 in an air contactor to form Na2CO3. If a source of calcium is available, then calcium carbonate can be produced which can be used or stored. Additionally, the process generates products for industrial decarbonization, such as hydrogen.