UCLA's ZIF Carbon Capture Crystals - A Smoke Stack's Best Friend

Chemists at UCLA have developed a synthetic gene that captures carbon emissions up to 400% more effectively.

The discovery could lead to cleaner energy, including technology that factories and cars can use to capture carbon dioxide before it reaches the atmosphere.

How it Works:

"We created three-dimensional, synthetic DNA-like crystals," says UCLA chemistry and biochemistry professor Omar M. Yaghi, who is a member of the California NanoSystems Institute (CNSI) at UCLA and the UCLA–Department of Energy Institute of Genomics and Proteomics.

"We have taken organic and inorganic units and combined them into a synthetic crystal which codes information in a DNA-like manner. It is by no means as sophisticated as DNA, but it is certainly new in chemistry and materials science."

The CO2 is captured using crystals made up of zeolitic imidazolate frameworks, or ZIFs (see photo inset).

"Once they trap it, they let the other gases go through," says Rahul Banerjee, a UCLA postdoctoral research scholar in chemistry on the project, suggesting the crystal structures could be potentially very useful to power plants looking to clean up their emissions.

Currently power plants send their flue gases through an amine solution, which he said is toxic by itself, and requires 20 to 30 percent of a plant's energy output. The amine bonds with the CO2, which can then be removed. The bonded solution then needs to be heated to release the CO2 for subsequent storage.

The new sponge-like ZIF material is a potentially lower-cost system for carbon capture. "It just costs you the zinc nitrate, which is pretty cheap and available in any chemical inventory," Banerjee comments.

He points out that zinc-oxide is a main ingredient in sunscreen, and that imidazoles are active ingredients of histidine, which is a minor acid.

"It's very much non-toxic and very much cost-effective, because here you don't have to do anything significant other than synthesizing the compound."

"You can fill this material into a smokestack, filled with all the ZIF, the zeolitic imidazolate material, and put them into that pipeline, and when the gas bubbles through the pipeline, you can trap the carbon dioxide selectively into the ZIF, and then let the other gases pass through."

Yaghi's History:

In the early 1990s, Yaghi invented a class of materials called metal-organic frameworks (MOFs), sometimes described as crystal sponges, in which he can change the components nearly at will.

MOFs have pores -- openings on the nanoscale in which Yaghi and his colleagues can store gases that are usually difficult to store and transport. Molecules can go in and out of the pores unobstructed. Yaghi and his research team have made thousands of MOFs.

Today:

Yaghi has been collaborating with his former UCLA chemistry colleague and former CNSI director Sir J. Fraser Stoddart on how to take concepts from biology and incorporate them into a synthetic material.

"We hope the materials we are creating will introduce a new class of structures that have controlled complexity," Yaghi said. "Chemists and materials scientists are now able to ask new questions we have never asked before. Also, new tools for characterizing the sequences and deciphering the codes within the crystals will have to be developed."

Sources: Carbon Capture Journal, Science Daily, and Clean Tech