Method and device for purifying cadmium in waste water through nano zero-valent iron

The invention relates to a method and a device for purifying cadmium in waste water through nano zero-valent iron, and the cadmium-contained waste water refers to the waste water with severe pollution and needing to be purified in the production and application field of smelting and different cadmium compounds. By adopting the nano technology, a great amount of cadmium elements in the waste water is purified and removed by utilizing nano zero-valent iron through a continuous flow secondary reaction device. Water is discharged in a weir flow way after the waste waster flows by a secondary treatment device consisting of a reaction chamber and a separation chamber, the waste water is adequately contacted and reacted with the nano zero-valent iron particles through the electric blending inside the reaction chamber, the nano zero-valent iron particles are promoted to precipitate by utilizing an oblique plate inside the separation chamber so as to be separated from the waste water, and the precipitated nano zero-valent iron backflows to the reaction chamber to be circulated. A layer of filter membrane is paved on a water outlet of a weir flow water outlet groove so as to filter the nano zero-valent iron particles which are not completely precipitated in the water. The process flow for removing cadmium pollutant in the waste water is simple, the cost is low, convenience in operation is achieved, the treatment effect is good, and no secondary pollution is caused.