中频超声对硅藻的灭活机制及安全性研究

发布时间：2018-03-07 13:26

本文选题：硅藻　切入点：超声波　出处：《重庆大学》2014年硕士论文　论文类型：学位论文

【摘要】：三峡水库的运行使得三峡大坝上游在汛期保持低水位运行，而在枯水期保持高水位运行，，库区的水文、水环境、水生态等较蓄水前发生了巨大的变化，三峡库区支流河道型的硅藻“水华”现象时有发生，严重影响供水安全。超声波较其他除藻工艺有着无可比拟的优势，而目前关于超声除藻的研究单一且不全面。本文针对三峡库区多以硅藻“水华”为主的特点，选择危害最大的针杆藻属硅藻为研究对象，探讨了超声对硅藻的灭活机制以及在这一过程中的有机物释放和降解规律，并对中频超声除（灭活）硅藻过程中的水质安全进行研究，取得了以下主要结论： 1）通过对中频超声在不同模式（频率、功率及长短期）下的效能、机制（机械效应及自由基氧化效应）以及灭活动力学进行了深入的研究，得出中频超声对硅藻的灭活是空化泡共振效应破坏叶绿体结构与羟基自由基氧化降解叶绿素a共同作用的结果。 2）停止超声处理后，针杆藻的光合参数Y、α以及rETRmax值会立即恢复，而由于超声在处理硅藻过程中抑制了藻细胞的分裂，因此叶绿素a的恢复明显滞后。 3）对超声灭活硅藻过程中有机物的释放与降解规律进行探索，通过测量水样中TOC的浓度以及观察细胞形态随超声时间的变化情况发现，在超声处理前10min，细胞去除率达86%，细胞破碎严重，且具有完整细胞形态的空壳细胞有90%，TOC浓度上升，有机物大量释放；10～15min后，TOC浓度下降，有机物被部分降解。结合1）中超声处理前10min针杆藻的光量子产量Y值降解曲线，分别与TOC浓度变化以及细胞去除率进行相关性分析，得出有机物的释放和细胞去除率随光合活性参数值的降低成比例的增加，在超声处理前10min，大部分细胞的完整性被破坏，胞内有机物也大量释放，因此在后期需进一步研究消毒副产物生成潜能，深入探讨有机物释放对饮用水安全的影响。
[Abstract]:The operation of the three Gorges Reservoir causes the upstream of the three Gorges Dam to maintain a low water level during flood season, while to maintain a high water level during the dry season. The hydrology, water environment, and water ecology of the reservoir area have undergone great changes compared with those before the water storage. The phenomenon of "Shui Hua" of diatoms in tributaries of the three Gorges Reservoir area occurs from time to time, seriously affecting the safety of water supply. Ultrasonic wave has an unparalleled advantage over other algal removal techniques. However, the current research on ultrasonic algal removal is single and incomplete. In view of the characteristics of "Shui Hua" in the three Gorges Reservoir area, the most harmful diatom, Diatom, is chosen as the research object in this paper. The mechanism of ultrasonic inactivation of diatoms and the release and degradation of organic matter in the process were discussed. The safety of water quality in the process of medium frequency ultrasonic removal (inactivation) of diatoms was studied. The main conclusions were as follows:. 1) the efficiency, mechanism (mechanical effect and free radical oxidation effect) and inactivation kinetics of intermediate frequency ultrasound in different modes (frequency, power, and short and long term) were studied. It is concluded that the inactivation of diatoms by intermediate frequency ultrasound is the result of the effect of cavitation bubble resonance effect on the destruction of chloroplast structure and the oxidation of chlorophyll a by hydroxyl radical. 2) the photosynthetic parameters (Y, 伪 and rETRmax) of Acetophyta recovered immediately after the treatment of ultrasound, but the recovery of chlorophyll a was obviously delayed because of the inhibition of cell division during the treatment of diatoms by ultrasound. 3) the rules of organic matter release and degradation in the process of ultrasonic inactivation of diatoms were explored. By measuring the concentration of TOC in water samples and observing the changes of cell morphology with ultrasonic time, it was found that. Ten minutes before ultrasound treatment, the cell removal rate reached 86%, the cell fragmentation was serious, and 90 of the empty shell cells with intact cell morphology increased TOC concentration, and the concentration of TOC decreased after 1015min after a large release of organic matter. Organic matter was partially degraded. In combination with 1) the degradation curve of photoquantum yield Y value of Phellodendron sp. 10 minutes before ultrasonic treatment was analyzed respectively with the change of TOC concentration and the cell removal rate. The results showed that the organic matter release and cell removal rate increased proportionally with the decrease of photosynthetic activity parameters. At 10 min before ultrasound treatment, the integrity of most of the cells was destroyed, and the intracellular organic matter was released in large quantities. Therefore, it is necessary to further study the generation potential of disinfection by-products and the effect of organic matter release on drinking water safety.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X524;TV697

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