超声灭活水中隐孢子虫影响因素及机制

Influence Factors and Mechanism of Ultrasonic Inactivating Cryptosporidium in Water

采用超声灭活隐孢子虫卵囊，超声频率为19．8kHz，功率为151w，温度控制在（20±1）℃，探讨了浊度、p（腐殖酸）及无机离子质量浓度对超声灭活隐孢子虫的影响，并通过扫描电镜观察及动力学分析探究了超声灭活隐孢子虫的机制．结果表明：在浊度为0～21．46NTU范围内，隐孢子虫的灭活率先升后降，浊度为1．13NTU时灭活率最高，为94．7％；隐孢子虫灭活率随P（腐殖酸）的增加而降低，当P（腐殖酸）为50．0mg／L时灭活率降至78．4％．Cu2＋、Mn2＋和SO42＋对灭活率影响较小，当p（Cu2＋）为0．5mg／L时，隐孢子虫灭活率（93．2％）比未添加Cu2＋时增加了0．7％；p（CO32＋）增加，隐孢子虫灭活率下降，当P（CO32-）为150mg／L时灭活率降至82．5％．扫描电镜形态学观察表明，超声可破坏隐孢子虫细胞结构；动力学分析表明，自由基氧化作用对灭活率的贡献为15．6％，说明超声灭活隐孢子虫的主要机制为空化作用产生的机械剪切作用．

The effects of turbidity, organic substance and inorganic ions on inactivation of Cryptosporidium with the ultrasonic frequency of 19.8 kHz,power of 151 W and temperature of （20 ± 1 ）℃ were investigated. Additionally, the mechanism of ultrasonic inactivation of Cryptosporidium was investigated by scanning the electron microscopy and dynamic analysis. The results indicated that the inactivation rate increased at first and then decreased in the range of 0-21.46 NTU. During this process, the highest inactivation rate was 94. 7% , when the turbidity was 1.13 NTU; the inactivation rate increased with the increase of the concentration of humic acid; the inactivation rate reduced to 78.4% when the concentration of humic acid was 50. 0 mg/L. The effects of CuE＋ , Mn2＋ and SO42- on the inactivation was negligible, since the inactivation rate merely heighten 0. 7% compared Cu2. concentration of 0. 5 and 0 mg/L; The inactivation rate dropped with the increase of CO32- concentration. It reduced to 82.5% when CO32- concentration was 150 mg/L. Moreover, the morphological observation by scanning electron microscopy showed that ultrasound was able to damage the cell structure of Cryptosporidium. It was suggested that the mechanical shear action produced by cavitation was the main mechanism of inactivating the species via ultrasound due to the free radical oxidation, which contributed to inactivation was 15.6% through kinetic constants analysis.