Scientists at Rice University have discovered an environmentally friendly carbon-capture method that could be equally adept at absorbing carbon dioxide emissions from industrial plants and at natural gas wells.
The Rice lab revealed in a proof-of-concept study that amine-rich compounds are highly effective at capturing greenhouse gas when combined with carbon-60 molecules.
Tests from one to 50 atmospheric pressures showed the Rice compound captured a fifth of its weight in carbon dioxide but no measurable amount of methane, and the material did not degrade over many absorption and desorption cycles.
Carbon-60 is a soccer ball-shaped molecule, also known as the “buckyball.” It turns out that the curvature of buckyballs may make them ideally suited to bind amine molecules that capture carbon dioxide but allow desirable methane to pass through.
Using buckyballs as crosslinkers between amines, the lab produced a brown, spongy material in which water-avoiding buckyballs forced the water-seeking amines to the outside, where passing carbon dioxide could bind to the exposed nitrogen.
The Rice compound compared favorably with other carbon-capture candidates based on metal organic frameworks (MOFs), but unlike MOFs, the Rice compound absorbed wet carbon dioxide as well as dry.
Compared to the cost of current amine used for industrial scrubbing, C-60 is expensive, so the researchers are pursuing ways to improve the compound’s capacity and rate of absorption.