Impacts On Microbially Mediated Geological CO₂ Storage By SO₂ In Saline Aquifers

The burning of fossil fuels have substantially increased the levels of CO₂ in the atmosphere from 280 ppm in the preindustrial age to 400 ppm at present,leading to significant global climate change.In the Paris agreement,China pledged to peak CO₂ emissions by around 2030,and set goals for reducing carbon emissions to contribute its share to limit climate change.Carbon capture and storage in deep saline aquifers is considered as a promising potential technology for reducing carbon emissions of fossil fuels.However,the indigenous microbial community and impurities in the CO₂ steam are still unresolved factors influence the CCS technology apply in the deep saline aquifers.The experiments were performed on a batch of samples subjected to a temperature of 55°C and pressure of 15 MPa to match realistic conditions.The water sample for chemical analysis was collected from the reservoir.The core samples were collected at about 1600 m below surface?m.b.s?,the reservoir.The microbe sample was collected from water sample of Shiqiangfeng reservoir.To match realistic conditions,the microbe sample was cultured in a modified MSM liquid culture medium.The main research results are as follows:?1?The existence of the SO₂ impurity inhibited the growth of the indigenous microbial community.Meanwhile,the underlying trends were relatively impervious to all,the indigenous microbial community were continued to proliferate after the adaptation.The diversity of the indigenous microbial community was increased.The dominant bacteria were inconsistent during the experiments.?2?The existence of the SO₂ impurity changed the microbial community structure.Firmicutes and Proteobacteria were dominant in the experiment.Psueudomonas sp.became the dominant bacteria was later than the previous work.The existence of the SO₂ impurity induced the growth of Exiguobacterium.?3?The existence of the SO₂ impurity reduce the pH value.The change of pH enhanced the dissolution of feldspar and clay minerals.Due to the existence of the SO₂ impurity,the increase of sulfate lead to the mass forming of gypsum.The existence of the SO₂ impurity could weaken the CO₂ solubility-trapping process.?4?The existence of the SO₂ impurity and the growing tendency of Exiguobacterium sp.kept acidic surrounding which against the carbon fixation.The existence of the SO₂ impurity could weaken the microbially mediated geological CO₂ solubility-trapping process.