Membrane Contractor for Seawater Purification

Scientists from the University of Pittsburgh, Arizona State University and University of California Irvine have developed a novel membrane contractor for simultaneous desalination and CO2 removal from seawater.

Description

Through chemical modification to the surface of desalination membranes, it is possible to electrochemically lower the pH of water at the membrane surface. This lowering of pH converts dissolved bicarbonate ions (HCO3-) in seawater to gaseous CO2 to be removed through bubbling. This CO2 can be stored elsewhere and provides an alternative carbon capture approach to direct air capture currently used in efforts to manage climate change and changes in ocean pH levels that can impact on sea life.

Applications

1. Removal of CO2 from seawater
2. Simultaneous desalination and carbon capture

Advantages

Current approaches to marine carbon dioxide removal (mCDR) have used an electrochemical cell, and while effective at CO2 removal they are expensive, energy intensive and require all of the seawater to be processed at once.

This novel approach to mCDR is designed to use surface coatings on desalination membranes (reverse osmosis (RO) or nanofiltration (NF)). Surface coatings on the membranes will result in electrochemical reduction of the seawater pH locally, allowing for removal of CO2 as the seawater passes through the desalination membrane.

Invention Readiness

Guanidine-Functionalized Aromatics (GFAs) and Carbonic Anhydrase (CA) have been identified as surface chemicals to locally lower seawater pH and allow for removal of CO2. Research is ongoing to examine the efficacy in terms of CO2 removal and energy consumption of both RO and NF membranes coated with GFAs or CA to determine which approach might be most scalable for mCDR. Current approaches to carbon capture, direct air capture, are of massive commercial interest to companies wishing to achieve net zero CO2 goals. This novel approach allowing capture of CO2 from the oceans is likely to attract attention from companies looking to offset their carbon footprint.

IP Status

https://patents.google.com/patent/WO2024196860A2