Saline aquifers are considered ideal subsurface sinks for large amounts of CO₂ storage. It is common to have trace levels of uranium-bearing minerals (naturally occurring radioactive material, NORM) in sandstone saline aquifers and CO₂ injection may cause uranium mobilization due to the coupled chemical and physical interactions at mineral-water interfaces. In this study, we developed a TOUGHREACT model to assess the uranium mobilization potential from uraninite (UO₂) dissolution induced by CO₂ injection into a hypothetical CO₂ storage reservoir with Fe(III)-bearing hematite in a time scale of 30 years CO₂ injection and 100 years after CO₂ injection. Numerical simulation results show that injection of CO₂ reduced pH and induced small amounts of hematite dissolution, which released Fe³⁺ into aqueous phase. Fe³⁺ together with dissolved bicarbonate species caused oxidative dissolution of UO₂ (Fe³⁺ serving as an oxidant), resulting in an increase of dissolved uranium concentrations in the CO₂ storage reservoir. However, the released uranium was limited to a small region close to Fe³⁺ supply source and the maximum concentration of released uranium was only 9.00 × 10⁻¹⁰ mol/kg in the CO₂ storage reservoir at t = 30 years. The availability of Fe³⁺ is the main factor that limits mineralized uranium release because the pH drop induced by CO₂ injection is not low enough to cause significant Fe³⁺ release. For sorbed uranium, the main factor that influences sorbed uranium release is pH because uranium sorption is amphoteric. Based on our simulation results, the pH range in the CO₂ storage reservoir does not cause a substantial release of sorbed uranium. Also, the potential for released uranium to migrate through a permeable zone in the caprock to the layer above the caprock and cause groundwater contamination is negligible. In summary, results from this study imply a very low risk of environmental contamination by bicarbonate and Fe(III)-induced uranium mobilization.

盐水层被认为是用于大量CO ₂储存的理想地下水槽。通常在砂岩盐水层中含有微量的含铀矿物质（天然放射性物质，NORM），由于矿泉水界面的化学和物理相互作用，CO ₂注入会引起铀动员。在这项研究中，我们开发了一个TOUGHREACT模型，以评估在30年的CO时间范围内，将CO ₂注入假想的带有Fe（III）的赤铁矿的CO ₂储集层中，注入CO ₂引起的铀尿石（UO ₂）溶出的铀动员潜力_2次注入和CO ₂后100年注射。数值模拟结果表明，注入CO ₂降低pH值并引起少量赤铁矿溶解，从而将Fe ³⁺释放到水相中。Fe ³⁺和溶解的碳酸氢盐类物质引起UO _2的氧化溶解（Fe ³⁺作为氧化剂），导致CO ₂储层中溶解铀的浓度增加。但是，在t = 30年​​时，CO ₂储集层中的释放铀被限制在靠近Fe ³⁺供应源的小区域，并且最大释放铀浓度仅为9.00×10 ^-10 mol / kg 。铁的可用性³⁺是限制矿化铀释放的主要因素，因为注入CO ₂引起的pH下降不足以导致Fe ^3+大量释放。对于吸附铀，影响吸附铀释放的主要因素是pH，因为铀吸附​​是两性的。根据我们的模拟结果，CO ₂储存库中的pH范围不会引起吸附铀的大量释放。而且，释放出来的铀穿过盖层中的可渗透区迁移到盖层上方的层并引起地下水污染的可能性可以忽略不计。总之，这项研究的结果表明，由碳酸氢盐和Fe（III）引起的铀动员对环境造成污染的风险非常低。