Scientists from Geociencias Barcelona del CSIC (GEO3BCN-CSIC) and the Universitat d'Alacant have explored a promising strategy to address one of the most pressing challenges of our time: carbon dioxide removal. The new study, published in the International Journal of Greenhouse Gas Control, identifies which industrial by-products are suitably reactive to remove CO2, either from the atmosphere or as a concentrated gas, and at what reaction rates.
According to this publication, led by Liam Bullock, Marie Curie Fellow at GEO3BCN-CSIC, Industrial by-products associated with the mining of diamonds, nickel, and ilmenite, as well as quarrying of dunite and marble, show favourable chemical indicators for effective CO2 removal.
Minerals that contain calcium and magnesium can react with CO2 in water to form bicarbonate alkalinity and carbonates in nature. When CO2 dissolves in water, it combines with these minerals to create soluble bicarbonate ions and carbonates, effectively storing the CO2 safely and permanently.
This process is crucial in natural systems, influencing water chemistry, pH balance, and the creation of geological features like limestone formations. Wastes such as those associated with diamonds, nickel, ilmenite, dunite and marble contain the necessary minerals for this reaction to occur and are therefore favourable for CO2 removal strategies.
"These materials generally contain high amounts of calcium- and magnesium-bearing minerals, desirable for reactions to convert CO2 into safe and stable bicarbonate solution or carbonate minerals," explains Dr Bullock. According to the researcher, reaction rates are comparable to those of natural rocks used in targeted CO2 removal methods, such as through the enhanced weathering of basalt.
The study explored 21 industrial by-product samples sourced from 12 industries and mining sites from 15 locations worldwide, including materials sourced from Spain, Australia, Canada and the United States. The aim is to assess their potential to react with CO2 when exposed to water. The materials were tested for over 100 hours in the Geosciences Barcelona geochemical laboratories of CSIC.
Apart from the significant reduction of CO2, the article suggests that there may be additional advantages for those using materials often considered unwanted or hazardous. Research experiments targeting the geochemical potential of certain fabrics, locations, and industries for CO2 removal, combined with comprehensive assessments of technology, economics, and lifecycle, could lead to potential future advantages in both environmental and economic aspects.
The article provides the fundamental results of the DETAILS projects, a European initiative led by Dr. Bullock, in partnership with Dr. José Luis Fernández-Turiel, a GEO3BCN-CSIC researcher. "The publication will provide key information to industrial sectors, academic groups, and specialized CO2 removal enterprises, where open and available information such as this can help to steer future decision-making and pilot projects," holds Dr Bullock.
The results will also allow for larger-scale, more targeted studies. Dr. Bullock emphasizes that "there is still a need" to build a comprehensive database of materials to act as potential CO2 removal feedstocks. This research is crucial for expanding our understanding of well-studied and lesser-known materials and their reactivity with CO2 and water.
Bullock, L. A., Fernandez-Turiel, J.-L., & Benavente, D. (2023). Experimental investigation of multiple industrial wastes for carbon dioxide removal strategies. International Journal of Greenhouse Gas Control, 129, 103990. https://doi.org/10.1016/j.ijggc.2023.103990
This work forms part of the EU Horizon 2020 DETAILS Project, Grant Agreement ID: 101018312.