PDF(Pubmed)
Abstract：
The sonochemical oxidation activity was investigated for gas saturation and gas sparging under various liquid levels and volumes in 300 kHz sonoreactors. The liquid levels and volumes ranged from 5λ (25 mm, 0.47 L) to 50λ (250 mm, 4.30 L) and two gas mixtures, Ar:O2 (75:25) and N2:O2 (75:25), were used. Two types of reaction kinetics were observed to quantitatively analyze the sonochemical oxidation reactions: zero-order (KI dosimetry: C0 = 60.2 mM) and first-order (Bisphenol A (BPA) degradation: C0 = 0.043 mM). The masses of the sonochemical oxidation reactions were calculated and compared rather than the concentrations to more accurately compare the sonochemical oxidation activity under different liquid volume conditions. First, as the liquid level or volume increased for the zero-order reactions, the concentration of I3- ions representing the volume-averaged activity decreased substantially for gas saturation owing to the increase in liquid volume. However, gas sparging substantially enhanced sonochemical oxidation activity, and the mass of I3- ions representing the total activity remained constant as the liquid level increased from 20λ because of the improved liquid mixing and a shift in the sonochemical active zone. Second, as evidenced by the zero-order reactions, the concentration of BPA decreased considerably as the liquid level or volume increased in the first-order reactions. When gas sparging was used, higher reaction constants were obtained for both gas mixtures, ranging from 40λ to 50λ. However, a comparison of the sonochemical oxidation activity in terms of the degraded mass of BPA was inapplicable as the concentration of BPA decreased substantially and a lack of reactants occurred for the lower liquid level and volume conditions as the irradiation time elapsed. Instead, using the first-order reaction constant, a comparison of the required reaction times for a specific removal efficiency (30%, 60%, and 90%) was proposed. Gas sparging can substantially reduce the reaction time required for a liquid level of 40λ or higher.
摘要：
在300kHz声反应器中，在各种液位和体积下，研究了气体饱和度和气体喷射的声化学氧化活性。液位和体积范围为5λ(25毫米，0.47L）至50λ（250mm，4.30L)和两种气体混合物，Ar:O2(75:25)和N2:O2(75:25)，被使用。观察到两种类型的反应动力学来定量分析声化学氧化反应：零级（KI剂量测定：C0=60.2mM）和一级（双酚A（BPA）降解：C0=0.043mM）。计算并比较了声化学氧化反应的质量而不是浓度，以更准确地比较不同液体体积条件下的声化学氧化活性。首先,随着零级反应的液位或体积增加，由于液体体积的增加，代表气体饱和的体积平均活性的I3-离子浓度大大降低。然而,气体喷射显著增强了声化学氧化活性，由于液体混合的改善和声化学活性区的位移，随着液位从20λ增加，代表总活性的I3-离子的质量保持恒定。第二,正如零级反应所证明的那样，在一级反应中，随着液位或体积的增加，BPA的浓度显着降低。当使用气体喷射时，两种气体混合物都获得了更高的反应常数，范围从40λ到50λ。然而,就BPA的降解质量而言，声化学氧化活性的比较是不适用的，因为随着辐照时间的流逝，BPA的浓度大大降低，并且在较低的液位和体积条件下缺乏反应物。相反，使用一阶反应常数，特定去除效率所需反应时间的比较(30%，60%,和90%)被提议。气体喷射可以显著减少40λ或更高的液位所需的反应时间。
