The treatment of wastewater by electrolysis or electrochemistry is distinguished according to the objects to be removed and the electrochemical effects produced. It can be divided into electrochemical oxidation, electrochemical reduction, electric flotation, and electrocoagulation.
Electrolyzers are equipped with pole plates. The plates are properly spaced to ensure low power consumption and easy installation, operation and maintenance. The electrolytic cell can be divided into unipolar and bipolar according to the way of connecting the power supply of the pole plate. The characteristic of the bipolar electrode electrolyzer is that the middle electrode generates bipolarity by electrostatic induction. Compared with the unipolar electrode electrolyzer, this electrolytic cell has simpler electrode connection, safer operation, and reduced power consumption. The anode is connected with the anode of the rectifier, and the cathode is connected with the cathode of the rectifier. After being energized, under the action of an external electric field, the anode loses electrons to cause an oxidation reaction, and the cathode gains electrons to cause a reduction reaction. The waste water flows through the electrolytic cell and acts as an electrolyte. The oxidation and reduction reactions occur at the anode and cathode respectively, and harmful substances are removed. This oxidation or reduction reaction directly on the electrode is called the primary reaction.
In our country, we mainly use direct electrolytic oxidation. The electrolytic wastewater treatment can also adopt indirect oxidation and indirect reduction methods, that is, the use of electrode oxidation and reduction products to chemically react with harmful substances in the wastewater to form water-insoluble precipitates. Separate and remove harmful substances. It has a good removal effect on COD, ammonia nitrogen and chroma in the degraded water.
Types of industrial wastewater treated by electrolysis:
The electrolysis method is mainly used to treat chromium-containing wastewater and cyanide-containing wastewater. In addition, it is also used to remove heavy metal ions, oil and suspended solids in wastewater; it can also condense and adsorb dye molecules in colloidal or dissolved state in wastewater, and oxidation-reduction can destroy chromogenic groups and achieve decolorization. The application of electrolysis to treat wastewater containing phenol, cadmium, sulfur, and organic phosphorus, as well as wastewater from the food industry, is also underway.