Learning about water treatment defoamers? This article is enough!


The problem of foam in water treatment has troubled many people, such as foam, surfactant foam, impact foam, peroxide foam, and foam produced by non oxidizing bactericides in the process of commissioning. Therefore, the use of defoamer in water treatment is quite common. This paper introduces the principle, classification, selection and dosage of defoamer comprehensively.


Defoamer, also known as defoamer, has the following principles:


01


Foam local surface tension decreases, resulting in foam bursting.


The origin of this mechanism is to spread higher alcohols or vegetable oils onto the foam. When they are dissolved in foam, the surface tension will be significantly reduced. Because these substances are generally less soluble in water, the decrease in surface tension is confined to the local part of the foam, and the surface tension around the foam is almost unchanged. The reduced surface tension is strongly pulled around, extended, and finally ruptured.


02


Bubble bursting due to destruction of membrane elasticity






The addition of defoamer to the foam system will diffuse to the gas-liquid interface, making it difficult for the surfactant with stabilizing foam to recover the elasticity of the membrane.


03


Promoting liquid membrane drainage


Defoamer can promote liquid membrane drainage, resulting in bubble burst. The rate of foam drainage can reflect the stability of foam. Adding a substance to accelerate foam drainage can also play a role in defoaming.


04


Bubble bursting can be caused by adding hydrophobic solid particles


The hydrophobic solid particles on the surface of bubbles attract the hydrophobic end of surfactants, which makes the hydrophobic particles hydrophilic and enter the water phase, thus playing the role of defoaming.


05


Solubilizing foam-enhancing surfactants can cause bubble bursting


Some low molecular substances which can mix well with the solution can make the bubble surfactant solubilized and its effective concentration reduced. The low molecular substances such as octanol, ethanol and propyl alcohol can not only reduce the concentration of surfactants in the surface layer, but also dissolve the surfactant adsorption layer to reduce the intermolecular tightness of the surfactant, thus reducing the stability of the foam.


06


Electrolyte Disintegration Surfactant Double Layer


With the interaction of double layer of foam surfactants, a stable foaming solution can be formed. The addition of ordinary electrolytes can dissolve the double layer of the surfactant to defoaming.