Study On The Effectiveness And The Mechanism Of Algal Inactivation By Ti/RuO₂ Electrocatalysis Oxidation

Eutrophication is becoming increasingly prominent in china. The massive propagation of algae is seriously worsening the ecological environment and the water quality, threatening the safety of drinking water. Many kinds of technology to eliminate algae and kill algae are the focus of the current research. The electrocatalysis oxidation technology which is simple, easily automation and compatible with the environment, has received many attention.Two measuring methods of cell viability which are the neutral red dyeing and the TTC- dehydrogenase activity determination are established in this paper. Study on the change of algae viability in the process of the electrocatalysis oxidation by the methods. From the change of algae viability and solution properties, it studies on the effectiveness and influencing factors of algae inactivation in the process of the electrocatalysis oxidation. The mechanism of algae inactivation by the electrocatalysis oxidation includes the current, hydroxyl radical, the pH value and so on. These aspects have been preliminarily explored.The results of research into algae viability detection show that: the method for TTC-dehydrogenase activity can detect the viability of microcystis aeruginosa, and make a quantitative determination well. The optimal conditions of determination is pH=7.5~8.0, Tris-HCl as a buffer solution deploy 0.2% TTC. Cell raise in the slution 8h~16h in 30~35℃, then extract TPF with 50% ethyl alcohol, at last use Hexane as extractant to remove pigment interference. The method of neutral red dyeing is mainly used to detect the integrity of individual algae cells, 0.02% neutral red dyes for 15min is the optimum condition.Studying on the effectiveness of algae inactivation in the electrocatalysis oxidation, we find the Ti/RuO2 electrocatalysis oxidation system has a better effectiveness of algae inactivation. When cell density is approximately 4×109~6×109/L and current density is 4mA/cm2, use Na2SO4 as electrolyte to treat sample for 7min, the dehydrogenase activity has a sharp decline, and the absorption value of TPF drops to 0.365, the dyeing rate of neutral red is 30.1%. At this time algae cell is unable to reproduce the growth even it is raised again in MA culture medium. We think cell is thoroughly inactivation.Studying on factors of algae inactivation in the process of the electrocatalysis oxidation, we find the current density, the reaction time and the cell initial density, play a important role in algae inactivation by the electrocatalysis oxidation. Increasing the current density, extending the reaction time and reducing the density of initial cells, all can make algae activity weak. Electrolyte types for the effectiveness of algae inactivation is not significant, but natural water as the electrolyte, the algae viability in process of the electrocatalysis oxidation rapidly declines and no highly toxic by-product is produced.Studying on the mechanism of algae inactivation by the electrocatalysis oxidation, the results show that: the electrocatalysis oxidation is accomplished by the combined action of the current, electric field and free radical. The hydroxyl radical plays a leading role. The change of pH value has little impact on the algae viability.