[SGC41-P02] H2 production and CO2 storage during peridotite serpentinization under CO2-rich hydrothermal conditions: Influence of pyroxene
Keywords:Pyroxene, Olivine, Hydrothermal, H2 production, CO2 storage
In this study, we examined the reactions in H2O-olivine/pyroxene-CO2 systems by performing hydrothermal experiments in 0.5 mol/L NaHCO3 solutions under conditions of 300 oC and 10 MPa. The results show that H2 was produced when olivine and/or pyroxene reacted in NaHCO3 solution, and the presence of pyroxene in starting material suppressed H2 production from per kg of mineral. Pyroxene was converted solely to serpentine, rather than brucite and magnesite even in CO2-contained solutions, which indicates CO2 mineralization was only realized in olivine-contained systems. In addition, the pyroxene serpentinization process is quicker than olivine. In the experiment with olivine/pyroxene weight ratio of 3/2, all of the pyroxene was altered after 72 h reaction, whereas half of the olivine particles have remained. Based on experimental results, we propose that the presence of pyroxene in starting material will suppress the H2 production and CO2 storage during peridotite alteration; however, the inhibition effect will be decreased along the reaction time.