Researchers are developing a new type of membrane aimed at desalinating seawater and capturing carbon dioxide from the ocean simultaneously. The team, led by Assistant Professor Katherine Hornbostel from the Swanson School of Engineering at the University of Pittsburgh, has received a $1.4 million grant from the National Oceanic and Atmospheric Administration (NOAA) and the Office of Naval Research (ONR) to develop this innovative membrane.
The researchers are exploring the use of specialized chemical groups coated on desalination membranes, which can effectively release carbon dioxide gas, enabling its capture, storage, or reuse. The team, which includes members from Arizona State University, University of California, Irvine, and the National Renewable Energy Laboratory (NREL), aims to demonstrate the feasibility of this approach.
"Removing carbon dioxide from the ocean is challenging, but making use of similar existing technologies for seawater desalination can make it more viable," says Hornbostel. "We are looking for an alternative solution that is both energy-efficient and cost-effective."
Common methods for direct ocean capture rely on electrochemical cells. While effective in removing carbon dioxide, these methods are energy-intensive and expensive. Hornbostel and her team aim to demonstrate that by coating desalination membranes with special chemical groups, carbon dioxide can be efficiently released, captured, stored, or reused, similar to the process of opening a carbonated beverage.
Compared to more traditional methods that involve electrochemically separating incoming seawater into alkaline and acidic streams, the team's approach requires significantly less electrical energy for carbon dioxide removal.
However, the team first needs to determine which membrane is most suitable for the bubbling process. They will study reverse osmosis (RO) and nanofiltration (NF) membranes. Nanofiltration membranes have lower energy requirements but lower carbon dioxide removal rates, while RO membranes have higher carbon dioxide removal rates but higher energy requirements.
"We plan to conduct a techno-economic evaluation that will allow us to compare these two options and determine which one is more scalable beyond the laboratory environment and in actual seawater desalination plants," says Hornbostel.
This two-year project, combining seawater desalination with a new membrane for ocean carbon dioxide removal, is also co-led by Professor Matthew Green from Arizona State University, Professor Jenny Yang from the University of California, Irvine, Dr. Abhishek Roy from NREL, and Dr. Mou Paul from the National Renewable Energy Laboratory.
The goal of this innovative research is to develop an efficient technology that addresses both seawater desalination and carbon dioxide capture, offering a feasible solution for removing salt and carbon from the ocean.
