Experimental Study On Degradation Of Refractory Pollutant By The Combined Reactor Of Hydrodynamic Cavitation Due To Triangular Orifices Plate And Venturi Tube

Hydrodynamic cavitation is a new technology in water treatment in recent years. There’s a large number of hydroxyl radicals produced during hydrodynamic cavitation reaction happens. Many refractory pollutants removed in a lower energy consumable and more efficiency condition by using hydrodynamic cavitation, and it also avoids secondary pollution. It is found that hydrodynamic cavitation technique has broad application and perspective compared with the traditional methods of its simple design, convenient operation and easy for business application.In this article, degradation on refractory wastewater was studied by the triangular orifices plate and Venturi tube as the generating device of hydrodynamic cavitation, which was designed in the Hydraulics Laboratory of Zhejiang University of Technology. At first, the influences of the throat length of Venturi tube on degradation of Nitrobenzene and Pharmaceutical wastewater were explored by using the Venturi hydrodynamic cavitation reactor. We find that the optimum length of the throat is20cm. On this basis, we investigate the influence on the degradation of mixture wastewater of hydrophilic and hydrophobic pollutants by the combined hydrodynamic cavitation reactor of triangular orifices plate and Venturi tube. The result shows that the numbers and size of orifice, initial concentration, cycle time, cavitation number and the sequence between triangular orifices plate and Venturi tube have effect on the degradation of pollutants. Then the impact of pressure characteristics was studied. And in order to explore the cavitation mechanism and find the best element which can enhance the cavitation phenomenon. We used the solution of methylene blue as the medium to capture the production of·OH radicals due to hydrodynamic cavitation and performed quantitative analysis. To verify the results, degradation on Pharmaceutical wastewater was studied. We explored the influences of the numbers, the size and the shape of orifice, initial concentration, cycle time, cavitation number and pH value, and found out the best orifices plate in processing Pharmaceutical wastewater by experiment. This study results could provide a reference for a design of multiple-orifice plate, and laid a foundation for the development and utilization of the cavitation.