02/04/2025

Study Explores a Greener Approach to CO₂ Capture using CaO-based sorbents derived from white mud and limestone

Researchers from C5Lab, the CERENA-Centro de Recursos Naturais e Ambiente, and the Centro de Química Estrutural (CQE) have just published a scientific article that explores a more sustainable approach to capturing carbon dioxide (CO₂) through the Calcium Looping (Ca-looping) process using calcium oxide (CaO) based sorbents from white mud (an industrial waste) and limestone.

In the experiments conducted at the laboratory scale, real flue gas from a cement plant was used, which allowed for the creation of laboratory conditions close to reality, enabling future industrial applications.

The study concludes that:

The white mud demonstrated a higher CO₂ capture capacity, showing potential interest for use in the Ca-looping process under real carbonation atmosphere conditions. This approach becomes an economically attractive option while contributing to the reduction of adverse environmental impacts associated with the high volume of Portuguese industrial waste.

Sorbents with a low silica (SiO₂) content capture more CO₂, while a higher content reduces capture.

The addition of steam potentially improves CO₂ capture capacity at a lower calcination temperature.

The study was published in Chemical Engineering and Processing: Process Intensification and represents an important contribution to the decarbonization of the cement industry and the valorization of waste.

Read the full scientific paper here.