Principle, classification, selection and dosage of defoamer
The foam problem in water treatment has troubled many people, debuting the initial foam, surfactant foam, impact foam, peroxide foam, circulating water treatment with non-oxidizing fungicide generated foam, etc., so the use of defoamer in water treatment is more common, this article comprehensively introduces the principle, classification, selection and dosage of defoamer! Methods of foam elimination 1.Physical methods From a physical point of view, the methods to eliminate foam mainly include the placement of baffles or filters, mechanical agitation, static electricity, freezing, heating, steam, radiation irradiation, high-speed centrifugation, pressure and pressure reduction, high-frequency vibration, instantaneous discharge and ultrasonic (acoustic liquid control), etc. All these methods promote the gas transmission rate at both ends of the liquid film and the liquid discharge of the bubble film to different degrees. The stability factor of the foam is less than the attenuation factor, and the number of bubbles is gradually reduced. However, the common disadvantage of these methods is that the use of environmental factors is strong, the defoaming rate is not high, and the advantages are environmental protection and high reuse rate. 2.Chemical methods The methods of removing foam from the chemical point of view mainly include chemical reaction method and the method of adding defoamer. The chemical reaction method refers to the chemical reaction between the foaming agent and the foaming agent by adding some reagents to produce a substance that is insoluble in water, thereby reducing the concentration of surfactant in the liquid film and promoting the rupture of the foam, but this method has shortcomings such as the uncertainty of the composition of the foaming agent and the harm to the system equipment caused by insoluble substances. Nowadays, the most widely used defoaming method in all walks of life is the method of adding defoaming agent. The biggest advantage of this method is that it has high defoaming efficiency and easy to use, but finding a suitable and efficient defoaming agent is the key. Principles of defoamer Defoamer, also known as defoamer, has the following principles: 1. The local surface tension of the foam is reduced, resulting in the collapse of the foam The origin of this mechanism is that high alcohols or vegetable oils are sprinkled on the foam, and when they dissolve into the foam solution, the surface tension there is significantly reduced. Because these substances are generally less soluble to water, the reduction in surface tension is limited to local areas of the foam, while the surface tension around the foam hardly changes. The portion with reduced surface tension is strongly pulled around, extended, and finally ruptured. 2.Damage the membrane elasticity and cause the bubble to burst When the defoamer is added to the foam system, it diffuses to the gas-liquid interface, which makes it difficult for the surfactant wit...
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