Captura, a company affiliated with the California Institute of Technology, is developing a system for extracting CO2 from seawater while returning the filtered water back to the ocean.
The carbon filtration process will utilize Captura’s patented electrolysis process known as Direct Ocean Capture (DOC). The company aims to remove carbon on a large scale at a lower cost compared to older methods. The system also exclusively uses renewable energy and seawater as inputs to minimize environmental impact, as reported by New Atlas on May 11.
Simulation of a large-scale facility by Captura for CO2 extraction from seawater. (Image: Captura)
The DOC technology has the capability to filter billions of tons of carbon from the ocean. In this process, cleaned seawater is brought into the filtering facility, where electrolysis technology is used to produce acid. This acid is then added back to the seawater, initiating a chemical reaction that separates CO2 from the water.
The process is accelerated by using gas-liquid contactors (a type of electrical switch) and vacuum pumps, creating a stream of CO2. This CO2 can then be isolated or reused for other purposes.
The neutralization of the seawater is accomplished by adding an alkaline substance. After this, the carbon-removed water is discharged back into the ocean. According to Captura, this water can continue to interact with the atmosphere to absorb a large amount of CO2 equivalent to the amount that was originally extracted. This remarkable capability makes the seawater filtration system an effective tool for mitigating the impacts of climate change.
In 2022, Captura established its first offshore testing facility in Newport Beach, California. The company uses a continuous flow of seawater to measure the system’s performance and make necessary improvements. Captura plans to continue enhancing the technology in the near future. The company also intends to collaborate with the AltaSea organization at the Port of Los Angeles to build a second DOC system capable of filtering 100 tons of CO2 from the ocean each year.
