Experimental study on sodium persulfate denitrification based on hydrodynamic cavitation
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摘要:
目的 为提高过硫酸钠（Na2S2O8）湿法氧化脱硝的效率以及药品利用率， 方法 利用水力空化强化Na2S2O8开展湿法氧化脱硝实验，探究水力空化强化Na2S2O8脱硝的可行性，研究溶液温度、Na2S2O8浓度、氯离子（Cl−）等因素对脱硝效果的影响以及相关机理。 结果 实验结果表明：水力空化产生的特殊环境有利于活化Na2S2O8，提高脱硝效率，但整体脱硝效果不佳；在实验条件下，当温度从30 ℃升到80 ℃时，一氧化氮(NO)去除率从7%提升至43%；提高Na2S2O8的浓度有利于提高NO脱除率；在高温工况下，提高Na2S2O8的浓度对提高整体脱硝率的促进作用更明显；Cl−的存在可以极大地提高NO的脱除率，当Cl−浓度与Na2S2O8浓度配比达到0.15∶0.1时，NO的脱除率高达94%。 结论 水力空化可促进Na2S2O8去除NO的反应速率，Cl−在水力空化创造的特殊反应环境中能产生更多的氧化性物质，提高了脱硝效果。 Abstract:Objectives In order to improve the efficiency of sodium persulfate (Na2S2O8) wet oxidation denitrification and its utilization rate, Methods this paper uses hydrodynamic cavitation to enhance Na2S2O8 for wet oxidation denitrification experiments, explores the feasibility of using hydraulic cavitation to enhance Na2S2O8 denitrification, and studies Na2S2O8 solution temperature and concentration, chloride ions (Cl−) and other factors on denitrification effects and related mechanisms. Results The experimental results show that the special environment created by hydrodynamic cavitation is beneficial for activating Na2S2O8 and improving its denitrification efficiency, but the overall denitrification effect is insufficient. Under the experimental conditions, when the temperature increases from 30°C to 80°C, the nitrigen oxide(NO)removal rate increases from 7% to 43%, showing that increasing the concentration of Na2S2O8 is beneficial for increasing the NO removal rate. Under high-temperature conditions, increasing the concentration of Na2S2O8 has a more obvious promotion effect on improving the overall denitrification rate. The presence of Cl−can greatly increase the NO removal rate. When the ratio of Cl− concentration to Na2S2O8 concentration reaches 0.15:0.1, the NO removal rate reaches 94%. Conclusions Hydrodynamic cavitation promotes the reaction rate of Na2S2O8 to remove NO. Cl− produces more oxidizing substances in the special reaction environment created by hydrodynamic cavitation, thereby improving the denitrification effect. -
Key words:
- hydrodynamic cavitation /
- sodium persulfate /
- denitrification /
- ship exhaust gas
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图 1 水力空化强化过硫酸钠脱硝系统
Figure 1. Hydrodynamic cavitation enhanced sodium persulfate denitrification system
图 2 溶液温度对处理后NO出口体积分数的影响
Figure 2. The influence of solution temperature on the volume fraction of NO outlet
图 3 Na2S2O8浓度对剩余NO体积分数的影响以及不同浓度条件下的气泡状态
Figure 3. The influence of Na2S2O8 concentration on residual NO volume fraction and bubble state under different concentration conditions
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