R2：結晶構造・結晶化学・物性・結晶成長・応用鉱物

17:45 〜 18:00研究発表優秀賞エントリー

[R2-09] Microbial Carbon Sequestration: Investigating Cyanobacteria-Mediated Alkalinity and Carbonate Precipitation on Fe- and Mg-Bearing Substrates

*Veronica Rosa¹, Sasha Wilson¹, Maija Rausdepp¹, Connor Turvey¹, Arif Hussein¹ (1. University of Alberta)

キーワード：

CDR、Cyanobacteria、Applied mineralogy

Storing CO₂ as alkalinity by dissolving silicate minerals is the most efficient form of carbon storage. Cyanobacteria can enhance alkalinity generation if provided with the correct nutrients to grow. This study investigates the potential for Mg- and Fe-rich minerals found in mine tailings to encourage alkalinity generation and cyanobacterial growth, aiming to quantify how Fe- and Mg-rich minerals can impact the growth of cyanobacterial mats. Eight bench-top experiments were conducted over 24 weeks using phlogopite (a mica), forsterite (olivine) and tailings from two mines containing up to 32% tetraferriphlogopite (a Fe-rich variety of phlogopite) and 22% forsterite respectively. Each substrate was tested under biotic and abiotic conditions. The experiments measured weekly changes in pH and alkalinity. At the end, aqueous samples were analyzed for cations and anions using ICP-MS, while solid samples were analyzed for carbonate content using TOC and TIC methods. Results showed that pH increased with biotic systems, showing a greater total alkalinity compared to abiotic setups and correlating with cyanobacterial photosynthesis. Alkalinity measurements indicated that cyanobacteria enhanced CO₂ sequestration. Tetraferriphlogopite-rich tailings and phlogopite supported higher microbial activity than olivine-rich materials. This could be attributed to the higher availability of Fe as a micronutrient from those mineral substrates. This study demonstrates that the potential of cyanobacteria to remove CO₂ from air can be enhanced in the presence of Fe-rich minerals as a source of micronutrients. These findings could inform strategies for utilizing a greater range of mine tailings that contain common minerals, such as micas, for carbon sequestration.