Industrial cleaning commonly used defoamer, how to correctly select and use?
Foam problems in water treatment troubled a lot of people, debugging the initial foam, surfactant foam, impact foam, peroxide foam, circulating water treatment by adding non-oxidizing biocides generated by the foam and so on, so the use of antifoam in water treatment is relatively common, this article comprehensively introduces the principle of antifoam agent, classification, selection and dosage!
Selection of defoamer
1、Defoamer /antifoam is insoluble or insoluble in the foaming liquid
In order to break the foam, the antifoam agent should be concentrated and centralized on the bubble film. In the case of foam-breaking agent, it should be concentrated and centralized in an instant, and in the case of foam-suppressing agent, it should be kept in this state frequently. So the antifoam agent is supersaturated in the foaming liquid, only insoluble or insoluble is easy to reach the supersaturated state. Insoluble or insoluble, it is easy to gather in the gas-liquid interface, it is easy to concentrate in the bubble film, in order to play a role in the lower concentration. Antifoam agent for the water system, the molecules of the active ingredient must be strong hydrophobic and weak hydrophilic, HLB value in the range of 1.5-3, the role of the best.
2、Surface tension of defoamer antifoam is lower than that of foaming liquid.
Only when the intermolecular force of defoamer is small and the surface tension is lower than that of foaming solution, the defoamer particles can be immersed and expanded on the bubble film. It is worth noting that the surface tension of the foaming solution is not the surface tension of the solution, but the surface tension of the foaming solution.
3、Anti-foaming agent and foaming liquid has a certain degree of affinity
As the defoaming process is actually a foam collapse rate and foam generation rate of competition, so the defoamer must be able to quickly dispersed in the foaming liquid, in order to quickly play a role in a wider range of foaming liquid. To make the defoamer diffusion faster, defoamer active ingredient must have a certain degree of affinity with the foaming liquid. Antifoam agent active ingredients and foaming liquid too pro, will dissolve; too sparse and difficult to disperse. Only if the affinity is appropriate, the effectiveness will be good.
4、No chemical reaction between defoamer and foaming liquid.
If the defoamer reacts with the foaming liquid, on one hand, the defoamer will lose its effect, on the other hand, it may produce harmful substances and affect the growth of microorganisms.
5、Small volatility of defoamer, long effect time
First of all, we need to determine the need to use defoamer system, is a water-based system or oil-based system. Such as fermentation industry, we need to use oily defoamer, such as polyether modified silicone or polyether class. Water-based coating industry should use water-based defoamer, silicone defoamer. Select the defoamer, compare the amount of additive, in reference to the price, can come up with the most applicable and economical defoamer products.
