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Lehigh team develops new more effective carbon capture sorbent; seawater effective regenerant

A team from Lehigh University has developed a Lewis acid-base interaction–derived hybrid sorbent with polyamine-Cu(II) complex (Polyam-N-Cu2+) enabling more than 5.0 mol of CO2 capture/kg sorbent—nearly two to three times greater capacity than most of the DAC sorbents reported to date.

The sorbent is mechanically strong, chemically stable, and amenable to efficient regeneration by salt solutions at an ambient temperature, including seawater. In addition, similar to other amine-based sorbents, this hybrid sorbent is regenerable with waste heat or thermal energy at <90 °C.

The desorbed CO2 is simultaneously sequestered as innocuous baking soda (sodium bicarbonate, NaHCO3).


Concept of CO2 sorption by polyamine-Cu(II) complex. Schematics of (A) the polymeric LAB interaction derived anion exchanger with carbonate binding, and (B) individual steps of the gradual progression of CO2 sorption (1: CO2 dissolution, 2: transport of non-ionized H2CO3 inside the ion exchanger, and 3: rapid neutralization with OHfollowed by selective binding of HCO3−). Chen et al.

An open-access paper on their work is published in Science Advances.


  • Hao Chen, Hang Dong, Zhongyu Shi and Arup K. Sengupta (2023) “Direct air capture (DAC) and sequestration of CO2: Dramatic effect of coordinated Cu(II) onto a chelating weak base ion exchanger.” Science Advances doi: 10.1126/sciadv.adg1956



We fairly recently had a discussion on atmospheric carbon dioxide capture, and a number of posters here were understandably very skeptical on cost and energy efficiency grounds.

This would appear, at least on the face of it, to answer those objections, and others

1. Ambient temperatures

2. Recyclable sorbent

3. Non toxic

We will have to see how it scales.


Instead of sucking planet-warming carbon dioxide from the atmosphere, some scientists are looking to capture it from the oceans. This makes a lot more sense aa CO2 in the oceans is 100 times as prevalent.


Interesting stuff!

From your link:

' But underground geologic storage areas, such as depleted oil reservoirs, are likely to get most of the ocean-derived CO2, Hatton said.

“You’re not going to be able to use all of it as a feedstock. You’ll run out of markets.” So, as he put it, “a significant amount of the captured CO2 will need to be buried underground.”'

My guess is that bicarbonate of soda would be easier to store in bulk, but that is a guess, not researched.

As another guess. we will use several techniques, not just one.


1 mole of NaOH per mole CO2.
NaOH and CO2 are about the same molecular weight
NaOH = about $500/MT, so cost of CO2--> NaHCO3 = $500/MT
Just for clearing off the beads.



Sorry for being dim, but I am not quite sure what you are saying.

How is the cost of NaOH relevant to the processing costs of producing it by this suggested method?

Great if it costs as little as that, of course, as that is way, way lower than anything I have seen for CO2 capture and sequestration, but I am just not seeing why it should relate?


It's the last step in the reaction in their link:
"Once in chloride form, the CO2 sorbent can be converted to hydroxyl form, Polyam-N-Cu2+(OH−)2, by the stoichiometric passage of equivalent amounts of dilute OH− as NaOH or Ca(OH)2".
$500/ton is about what Direct Air Capture costs; not cheap. Biochar is more reasonable, somewhere around $50-100/MT-CO2.



I was reading MT as megaton, not metric ton! :-0

$500 ton is way too expensive, not sure what they are thinking


Don't put it in the air sequester power plants


This is way above my head.
No way could I puzzle through it to even work out what questions to ask.

I have to assume that the guys who developed this think that there is some potential to make this something like economic, but it is pointless my even asking what the source is for matt's figure of $500 ton since I won't be able to follow any reactions and costs laid out for me.

I am just going to have to wait to see what develops, if anything.

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