Spain The Function and Use of Defoaming Agents for Electroplating Wastewater Treatment(4)
Defoaming agents should have the following properties: ① strong defoaming power and low dosage; ② Adding to the foaming system does not affect the basic properties of the system, i.e. does not react with the defoaming system; ③ Low surface tension; ④ Good balance with the surface; ⑤ Good heat resistance; ⑥ Good diffusion and permeability, high positive spreading coefficient; ⑦ Chemical stability, strong oxidation resistance; ⑧ Good gas solubility and permeability; ⑨ Low solubility in foaming solutions; ⑩ No physiological activity, high safety.
Spain Chemical foam in electroplating wastewater treatment is due to the existence of many surfactants such as detergent and colloidal organic matter in the wastewater, which have strong foaming ability. Therefore, under the conditions of water flow speed, fall, aeration, blowing off, etc., a large number of small and light white brown foam will appear on the surface of the wastewater, which is unstable. There are still some differences between biological foam and chemical foam in appearance, usually showing soil brown or grayish brown. There are many reasons for this kind of foam, such as the soil brown foam caused by the low dissolved gas in the biochemical tank. Grey brown foam produced by low MLSS. Foam caused by microbial factors such as microbial abnormalities. Filamentous bacteria grow abnormally, mix and accumulate with foaming and floc particles to form foam that is difficult to eliminate, etc. The defoamer for electroplating wastewater treatment uses modified silicon polyether and modified oxane as the main raw materials to eliminate foam. It can achieve good results for chemical foam and biological foam that may appear in the electroplating wastewater system.