Rice University scientists’ method could reduce both emissions and building construction costs
Scientists at Rice University have found a way to process wood to trap carbon dioxide. This is a scalable and energy efficient process that can also strengthen materials enough to be used in construction.
Structural materials like steel and cement have high costs in both dollars and carbon footprint. Building construction and use accounts for an estimated 40% of emissions. Developing sustainable alternatives to existing materials can help mitigate climate change and reduce carbon emissions.
According to a study published in Cell Reports Physical Science, materials scientist Muhammad Rahman and co-workers incorporated molecules of a crystalline, porous material that trap carbon dioxide into wood to address both issues simultaneously. I found a way.
“Timber is a sustainable and renewable structural material that is already in widespread use.”
Rahman said. “Our engineered wood showed higher strength than normal untreated wood.”
To accomplish this feat, the network of cellulose fibers that give wood its strength is first removed by a process known as delignification.
“Wood is made up of three essential components: cellulose, hemicellulose and lignin,” says Rahman. “The lignin gives the wood its color, so when the lignin is removed it becomes colorless. Removal of the lignin is a fairly simple process involving a two-step chemical treatment using environmentally friendly substances. Then use bleach or hydrogen peroxide to remove the hemicellulose.”
The delignified wood is then soaked in a solution containing fine particles of an organometallic framework (MOF) known as Calgary Framework 20 (CALF-20). MOFs are high surface area adsorbent materials used for their ability to adsorb carbon dioxide molecules into their pores. “MOF particles readily fit into cellulose channels and attach to them through favorable surface interactions,” said Soumyabrata Roy, a Rice research scientist and lead author of the study.
MOF is one of several early carbon capture technologies developed to combat man-made climate change. “At the moment, there are no biodegradable and sustainable substrates for deploying carbon dioxide absorbing materials,” said Rahman. “Our MOF-enhanced wood is an adaptable support platform for deploying sorbents for a variety of carbon dioxide applications.”
“Many of the existing MOFs are not very stable in various environmental conditions,” says Roy. “Some are very sensitive to moisture, which is undesirable for structural materials.”
But CALF-20, developed by University of Calgary Professor George Shimizu and his collaborators, stands out for both its level of performance and versatility under a variety of environmental conditions, Roy said.
“The manufacture of structural materials such as metals and cement is a significant source of industrial carbon emissions,” Rahman said. “Our process is simpler and ‘greener’, both in terms of the materials used and the treatment of by-products.
“The next step is to determine the sequestration process and detailed economic analysis to understand the scalability and commercial potential of this material,” he added.
Original: Processed wood becomes stronger while trapping carbon dioxide
Than: Rice University | University of Calgary
