With increasing global climate change, integrated concepts to innovate sustainable structures that can multiaxially address CO2 mitigation are crucial. Building construction and use are estimated to be responsible for 40% of carbon dioxide emissions, making structural elements like steel or cement expensive financially and environmentally.
Creating environmentally friendly substitutes for current materials could help slow global warming and cut carbon dioxide emissions. Scientists at Rice University have developed a method to strengthen Wood for use in the building while also engineering it to trap carbon dioxide through a technique that may be scaled up and uses less energy.
Scientists found a way to incorporate molecules of a carbon dioxide-trapping crystalline porous material into Wood.
Materials scientist Muhammad Rahman said, “Wood is a sustainable, renewable structural material that we already use extensively. Our engineered Wood did exhibit greater strength than normal, untreated Wood.”
“To achieve the feat, the network of cellulose fibers that gives wood its strength is first cleared out through a process known as delignification.”
“Wood comprises three essential components: cellulose, hemicellulose, and lignin. Lignin is what gives Wood its color, so when you take lignin out, the Wood becomes colorless. Removing the lignin is a simple process that involves a two-step chemical treatment using environmentally benign substances. After removing the lignin, we use bleach or hydrogen peroxide to remove the hemicellulose.”
The delignified Wood is then immersed in a solution containing tiny pieces of Calgary Framework 20 (MOF), a metal-organic framework (CALF-20). MOFs are sorbent materials with a large surface area that are employed for their capacity to adsorb carbon dioxide molecules into their pores.
Soumyabrata Roy, a Rice research scientist and lead author of the study, said, “The MOF particles easily fit into the cellulose channels and get attached to them through favorable surface interaction.”
Rahman said, “MOFs are among several nascent carbon capture technologies developed to address anthropogenic climate change. Currently, no biodegradable, sustainable substrate for deploying carbon dioxide-sorbent materials exists. Our MOF-enhanced Wood is an adaptable support platform for deploying sorbent in different carbon dioxide applications.”
Roy said, “Many existing MOFs are unstable in varying environmental conditions. Some are susceptible to moisture, and you don’t want that in structural material.”
“CALF-20, however, stands out in terms of both performance level and versatility under various environmental conditions.”
Rahman said, “Manufacturing structural materials such as metals or cement represents a significant source of industrial carbon emissions. Our process is simpler and ‘greener’ regarding substances used and processing byproducts.”
“The next step would be to determine sequestration processes as well as a detailed economic analysis to understand the scalability and commercial viability of this material.”