微气泡强化磷酸介质中Fe^(2+)高效氧化研究

Microbubble enhanced Fe^(2+) oxidation in phosphoric acid solution

为实现酸性介质中Fe^(2+)的高效分离,工业中常采用双氧水氧化法将Fe^(2+)转化为溶解度更低的Fe3+而实现铁的析出,该方法双氧水利用率低,经济性差,亟待开发酸性介质中新型的Fe^(2+)低成本高效氧化法。基于微气泡在酸性介质中可爆裂生成活性氧原理,本工作开发了微气泡强化氧化Fe^(2+)技术,研究了曝气头尺寸、反应温度、酸浓度等对微气泡强化氧化Fe^(2+)及羟基自由基生成的影响,确定了反应的最佳条件为90℃、30wt%H_(3)PO_(4)、0.22μm孔径曝气头,在上述条件下,30 min Fe^(2+)氧化率可达约99%,与现行H_(2)O_(2)氧化效果相当,大大降低工艺经济成本。同时,本工作对微气泡强化Fe^(2+)氧化的机理进行了研究,确定了微气泡爆裂生成的主要活性氧为羟基自由基,并研究了曝气头尺寸、反应温度、酸浓度等对羟基自由基生成的影响,获得了酸性介质中羟基自由基生成的调控规律。

In order to realize the efficient separation of Fe^(2+) in acidic media, hydrogen peroxide oxidation method is often used in industry to transform Fe^(2+) into Fe3+ with lower solubility to realize the precipitation of iron.Due to the low utilization rate of hydrogen peroxide and poor economy, it is urgent to develop a new Fe^(2+) low-cost and high-efficiency oxidation method. Based on the principle that reactive oxygen species can be generated during the microbubbles bursting, the microbubble enhanced Fe^(2+) oxidation technology had been developed in this study. The effect of the aeration head aperture, reaction temperature, and acid concentration on the oxidation efficiencies of Fe^(2+) and·OH production were studied. The oxidation efficiency of Fe^(2+) can reach to 99% within 30 min under the optimized conditions(90℃, 30 wt% H_(3)PO_(4), 0.22 μm aeration head aperture). The oxidation effect of microbubble enhanced technology was comparable to the current H_(2)O_(2) oxidation,and greatly reduced the economic cost of the process. Moreover, the mechanism of Fe^(2+) oxidation enhanced by microbubbles was studied in this work, and the main reactive oxygen species generated by microbubbles bursting were determined to be hydroxyl radicals, and the influences of aeration head aperture, reaction temperature and acid concentration on the generation of hydroxyl radicals were studied, so as to obtain the regulation rules of hydroxyl radicals in acidic media.