CO₂ capture and utilization (CCU) is a process that captures CO₂ emissions from sources such as fossil fuel power plants and reuses them so that they will not enter the atmosphere. Among the various ways of recycling CO₂, reduction reactions are extensively studied at lab-scale. However, CO₂ reduction by standard methods is difficult. Sonochemistry may be used in CO₂ gas mixtures bubbled through water subjected to ultrasound waves. Indeed, the sonochemical reduction of CO₂ in water has been already investigated by some authors, showing that fuel species (CO and H₂) are obtained in the final products. The aim of this work is to model, for a single bubble, the close coupling of the mechanisms of bubble dynamics with the kinetics of gas phase reactions in the bubble that can lead to CO₂ reduction. An estimation of time-scales is used to define the controlling steps and consequently to solve a reduced model. The calculation of the concentration of free radicals and gases formed in the bubble is undertaken over many cycles to look at the effects of ultrasound frequency, pressure amplitude, initial bubble radius and bubble composition in CO₂. The strong effect of bubble composition on the CO₂ reduction rate is confirmed in accordance with experimental data from the literature. When the initial fraction of CO₂ in the bubble is low, bubble growth and collapse are slightly modified with respect to simulation without CO₂, and chemical reactions leading to CO₂ reduction are promoted. However, the peak collapse temperature depends on the thermal properties of the CO₂ and greatly decreases as the CO₂ increases in the bubble. The model shows that initial bubble radius, ultrasound frequency and pressure amplitude play a critical role in CO₂ reduction. Hence, in the case of a bubble with an initial radius of around 5 μm, CO₂ reduction appears to be more favorable at a frequency around 300 kHz than at a low frequency of around 20 kHz. Finally, the industrial application of ultrasound to CO₂ reduction in water would be largely dependent on sonochemical efficiency. Under the conditions tested, this process does not seem to be sufficiently efficient.

CO ₂捕获和利用（CCU）是一种过程，用于捕获 化石燃料发电厂等来源的CO ₂排放，并对其进行再利用，以使它们不会进入大气。在各种回收CO _2的方法中，在实验室规模上对还原反应进行了广泛的研究。但是，通过标准方法减少CO ₂是困难的。声化学可用于在经过超声波的水中鼓泡的CO ₂气体混合物中。确实，一些作者已经研究了声化学还原水中的CO _2的方法，表明燃料种类（CO和H ₂）是在最终产品中获得的。这项工作的目的是为单个气泡建模气泡动力学机制与气泡中可以导致CO ₂还原的气相反应动力学的紧密耦合。时间尺度的估计用于定义控制步骤，从而解决简化的模型。气泡中形成的自由基和气体的浓度需要经过多个周期的计算，才能观察超声频率，压力幅度，初始气泡半径和CO _2中气泡组成的影响。根据文献的实验数据证实了气泡组成对CO ₂还原速率的强烈影响。当初始CO ₂分数在气泡低的情况下，相对于没有CO _2的模拟，气泡的生长和破裂被轻微地改变，并且促进了导致CO ₂还原的化学反应。但是，峰值塌陷温度取决于CO ₂的热性质，并且随着气泡中CO _2的增加而大大降低。该模型表明，初始气泡半径，超声频率和压力幅度在减少CO ₂方面起着至关重要的作用。因此，在气泡的初始半径为约5μm的情况下，在约300kHz的频率处的CO ₂还原似乎比在约20kHz的低频下的CO ₂还原更有利。最后，超声波在CO中的工业应用₂水的减少在很大程度上取决于声化学效率。在测试的条件下，此过程似乎效率不高。