The fluorescence staining method and scanning electron microscopy （SEM） were used to study the effect of ozone （O3） inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mec...The fluorescence staining method and scanning electron microscopy （SEM） were used to study the effect of ozone （O3） inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mechanism of inactivation preliminarily. Results indicated that O3 had a stronger inactivating capability. When the concentration of O3 was above 3.0 mg/L and the contact time was up to 7 min, a significant inactivating effect could be achieved. The turbidity on inactivation effects was also found to be statistically significant in artificial water. With increases in turbidity, the inactivating effect decreased. Inactivation rate improved with a temperature increase from 5 to 25℃, but decreased beyond this. The inactivating capability of O3 was found to be stronger under acidic than that under alkalic conditions. When the concentration of organic matter in the reaction system was increased, the competition between Cryptosporidium and organics with O3 probably took place, thereby reducing the inactivation rate. In addition, the cellular morphology of Cryptosporidium varied with different contact times. At zero contact time, cells were rotundity and sphericity, at 60 sec they became folded, underwent emboly, and burst at 480 sec, the cell membrane of Cryptosporidium shrinked and collapsed completely.展开更多
Microcystins, which represents one kind of cancerogenic organic compounds, is abundant in eutro- phication water. The effects of reaction factors on chlorine dioxide （C102） for removal of low-concentration Micro- cy...Microcystins, which represents one kind of cancerogenic organic compounds, is abundant in eutro- phication water. The effects of reaction factors on chlorine dioxide （C102） for removal of low-concentration Micro- cystin-LR, Microcystin-RR, and Microcystin-YR in water as well as the reaction mechanisms was investigated by using enzyme-linked immunosorbent assay （ELISA） kit and gas chromatography-mass spectrometry （GC-MS）. The results showed that MC-LR, MC-RR, and MC-YR could be efficiently decomposed by C102. The degradation efficiency was shown positively correlated to the concen- tration of C102 and reaction time; while the effect of reaction temperature and pH is slight. The kinetic constants and activation energies of the reaction ofMC-LR, MC-RR, and MC-YR with C102 are determined as 459.89, 583.15, 488.43 L.（mol.min）I and 64.78, 53.01, 59.15kJ.mok1, respectively. As indicated by high performance liquid chromatography mass spectrometer （HPLC-MS） analysis, degradation should be accomplished via destruction of Adda group by oxidation, with the formation of dihydroxy substituendums as end products. This study has provided a fundamental demonstration of C102 serving as oxidizing disinfectant to eliminate microcystins from raw water source.展开更多
基金supported by the National High Technology Research and Development Program (863) of China(No. 2006AAZ309)
文摘The fluorescence staining method and scanning electron microscopy （SEM） were used to study the effect of ozone （O3） inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mechanism of inactivation preliminarily. Results indicated that O3 had a stronger inactivating capability. When the concentration of O3 was above 3.0 mg/L and the contact time was up to 7 min, a significant inactivating effect could be achieved. The turbidity on inactivation effects was also found to be statistically significant in artificial water. With increases in turbidity, the inactivating effect decreased. Inactivation rate improved with a temperature increase from 5 to 25℃, but decreased beyond this. The inactivating capability of O3 was found to be stronger under acidic than that under alkalic conditions. When the concentration of organic matter in the reaction system was increased, the competition between Cryptosporidium and organics with O3 probably took place, thereby reducing the inactivation rate. In addition, the cellular morphology of Cryptosporidium varied with different contact times. At zero contact time, cells were rotundity and sphericity, at 60 sec they became folded, underwent emboly, and burst at 480 sec, the cell membrane of Cryptosporidium shrinked and collapsed completely.
文摘Microcystins, which represents one kind of cancerogenic organic compounds, is abundant in eutro- phication water. The effects of reaction factors on chlorine dioxide （C102） for removal of low-concentration Micro- cystin-LR, Microcystin-RR, and Microcystin-YR in water as well as the reaction mechanisms was investigated by using enzyme-linked immunosorbent assay （ELISA） kit and gas chromatography-mass spectrometry （GC-MS）. The results showed that MC-LR, MC-RR, and MC-YR could be efficiently decomposed by C102. The degradation efficiency was shown positively correlated to the concen- tration of C102 and reaction time; while the effect of reaction temperature and pH is slight. The kinetic constants and activation energies of the reaction ofMC-LR, MC-RR, and MC-YR with C102 are determined as 459.89, 583.15, 488.43 L.（mol.min）I and 64.78, 53.01, 59.15kJ.mok1, respectively. As indicated by high performance liquid chromatography mass spectrometer （HPLC-MS） analysis, degradation should be accomplished via destruction of Adda group by oxidation, with the formation of dihydroxy substituendums as end products. This study has provided a fundamental demonstration of C102 serving as oxidizing disinfectant to eliminate microcystins from raw water source.
