Foam problems in water treatment have troubled many people. Foam in the early stage of debugging, surfactant foam, impact foam, peroxide foam, foam produced by adding non-oxidizing bactericides in circulating water treatment, etc., so disinfection in water treatment The use of foaming agents is relatively common. This article comprehensively introduces the principle, classification, selection and dosage of defoaming agents!

Defoaming principle
(1) The local surface tension of the foam decreases, causing the bubble to burst.
(2) Destroy the elasticity of the membrane and cause the bubbles to burst.
(3) Promote liquid membrane drainage
(4) Adding hydrophobic solid particles can cause bubbles to collapse
(5) Solubilizing and foaming surfactants can cause bubbles to burst
(6) The electrolyte disintegrates the surfactant double electrical layer

Defoaming agent classification
Commonly used defoaming agents can be divided into silicone (resin), surfactant, paraffin and mineral oil based on different components.
(1) Silicone (resin) type
Silicone defoamer is also called emulsion defoamer. The method of use is to emulsify and disperse silicone resin in water with an emulsifier (surfactant) and then add it to the wastewater. Silica fine powder is another silicon defoaming agent with good defoaming effect.
(2) Surfactants
This type of defoaming agent is actually an emulsifier, which uses the dispersing effect of surfactants to keep the foam-forming substances dispersed in a stable emulsified state in the water, thereby avoiding the generation of foam.
(3) Alkanes
Paraffinic defoamer is a defoamer made by emulsifying and dispersing paraffin wax or its derivatives with an emulsifier. Its use is similar to that of surfactant emulsified defoamer.
(4) Mineral oils
Mineral oil is the main defoaming ingredient. In order to improve the effect, metal soap, silicone oil, silica and other substances are sometimes mixed together. In addition, in order to make the mineral oil easily spread to the surface of the foaming liquid, or to make the metal soap and the like evenly dispersed in the mineral oil, various surfactants can sometimes be added.


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