Coral reef-inspired building method turns captured carbon into fire-resistant materials
Original story by Will Kwong
A new method inspired by coral reefs can capture carbon dioxide (CO2) from the atmosphere and transform it into durable, fire-resistant building materials, offering a promising solution for carbon-negative construction.
The approach, developed by USC researchers and detailed in a study published in npj Advanced Manufacturing, draws inspiration from ocean corals’ natural ability to create robust structures by capturing CO2 from the environment and converting it to calcium carbonate. The process developed at USC turns captured CO2 into a mineral-polymer composite that demonstrates extraordinary mechanical strength, including resistance to fractures and fire.
“This is a pivotal step in the evolution of converting carbon dioxide,” said Qiming Wang, associate professor of civil and environmental engineering at the USC Viterbi School of Engineering. “Unlike traditional carbon capture technologies that focus on storing carbon dioxide or converting it into liquid substances, we found this new electrochemical manufacturing process converts the chemical compound into calcium carbonate minerals in 3D-printed polymer scaffolds.”
Wang recently received a two-year Wrigley Institute Faculty Innovation Award to advance his development of the new process. To date, Wang and his collaborators have created proof-of-concept materials in the lab. The award will help fund the creation of real world-scale structures in a natural environment.
Taking inspiration from nature
This new method offers a solution that is less expensive than storing CO2 or converting it into a liquid. It also improves the usefulness of captured carbon by integrating it directly into building materials.
Wang attributed the “magic of ocean coral” as fundamental to the study’s breakthrough. “As an organism, coral can use photosynthesis to capture carbon dioxide from the atmosphere and convert it into a structure,” Wang said.
The method was directly inspired by how coral creates its unique skeletal structures, known as corallites. In nature, coral builds corallites through a process called biomineralization, in which coral combines the CO2 captured from photosynthesis with calcium ions from seawater. The resulting calcium minerals then attach to organic templates formed by the corals, creating the sturdy structures that together make up massive ocean reefs.
The research team replicated this process by creating 3D-printed polymer scaffolds that mimicked coral’s organic templates. They then coated the templates with a thin conductive layer, connected the coated structures to electrochemical circuits, and immersed them in a calcium chloride solution.
When carbon dioxide was added to the solution, it broke down into bicarbonate ions. These ions reacted with calcium in the solution to form calcium carbonate, which gradually filled the 3D-printed pores. This resulted in the final product, a dense mineral-polymer composite.