How to choose defoamer?

The selection of defoamer should accord with the following points:

1. Insoluble or insoluble in foaming fluid

To dissolve the foam, defoamer should be concentrated and concentrated on the bubble film. For the case of defoamer, it should be concentrated and concentrated instantaneously, and for the case of foam suppression, it should always be kept in this state. So defoamer is supersaturated in foaming liquid, only insoluble or insoluble can it easily reach supersaturated state. Insoluble or insoluble, it is easy to gather at the gas-liquid interface, it is easy to concentrate on the vesicle membrane, in order to play a role at a lower concentration. The molecule of active ingredient must be strong hydrophobic and weak hydrophilic. The HLB value is in the range of 1.5-3, and the effect is the best.

2. Surface tension is lower than foaming fluid

Only when the intermolecular force of the defoamer is small and the surface tension is lower than that of the foaming liquid, the defoamer particles can be immersed and expanded in the membrane. It is noteworthy that the surface tension of foaming solution is not the surface tension of solution, but the surface tension of foaming solution.

3. A certain degree of affinity with foaming fluid

Since the defoaming process is actually the competition between the rate of bubble collapse and the rate of foam formation, defoamers must be dispersed rapidly in the foaming solution so as to play a role in the wider range of foaming liquid. In order to make the defoamer diffuse quickly, the active ingredients of defoamer must have affinity with the foaming fluid to a certain extent. The active ingredients of defoamers can dissolve when they are related to the foaming fluid; they are too sparse and difficult to disperse. Effectiveness will be better only if it is appropriate to be close and sparse.

4. No chemical reaction with foaming fluid

The defoamer reacts with the foaming fluid. On the one hand, the defoamer will lose its function, on the other hand, it may produce harmful substances, which affect the growth of microorganisms.

5. Low volatility and long action time

First of all, it is necessary to determine the system that needs to use defoamer, which is water-based system or oil-based system. For example, in the fermentation industry, oily defoamers, such as polyether modified silicon or polyether, should be used. Water-borne coatings industry needs water-borne defoamer, organosilicon defoamer. The most suitable and economical defoamer can be obtained by choosing defoamer and comparing the amount of defoamer and the reference price.

--Reprinted from Environmental Protection Home